ETH Price: $1,971.87 (-0.12%)

Transaction Decoder

Block:
13367911 at Oct-06-2021 09:46:45 PM +UTC
Transaction Fee:
0.03153252225737373 ETH $62.18
Gas Used:
199,910 Gas / 157.733591403 Gwei

Emitted Events:

130 TransparentUpgradeableProxy.0x85291dff2161a93c2f12c819d31889c96c63042116f5bc5a205aa701c2c429f5( 0x85291dff2161a93c2f12c819d31889c96c63042116f5bc5a205aa701c2c429f5, 0x000000000000000000000000a0b86991c6218b36c1d19d4a2e9eb0ce3606eb48, 0x000000000000000000000000c8484d4a6baaaa7c31f411b1362145da109f9b50, 0x000000000000000000000000c8484d4a6baaaa7c31f411b1362145da109f9b50, 000000000000000000000000cee284f754e854890e311e3280b767f80797180d )
131 FiatTokenProxy.0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef( 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef, 0x000000000000000000000000c8484d4a6baaaa7c31f411b1362145da109f9b50, 0x000000000000000000000000cee284f754e854890e311e3280b767f80797180d, 0000000000000000000000000000000000000000000000000000000b90d3f1b1 )
132 TransparentUpgradeableProxy.0x23be8e12e420b5da9fb98d8102572f640fb3c11a0085060472dfc0ed194b3cf7( 0x23be8e12e420b5da9fb98d8102572f640fb3c11a0085060472dfc0ed194b3cf7, 0x0000000000000000000000000000000000000000000000000000000000026964, 0xb73592da8e3ccfae1aa9a0916dcbf7d052683f3479bd8aaf635623885c1aab8f, 0000000000000000000000004dbd4fc535ac27206064b68ffcf827b0a60bab3f, 0000000000000000000000000000000000000000000000000000000000000009, 000000000000000000000000cee284f754e854890e311e3280b767f80797180d, 6af20a7156c02af55378963cfe214ed5e129c3345e13a3441ff16ab783125f60 )
133 TransparentUpgradeableProxy.0xff64905f73a67fb594e0f940a8075a860db489ad991e032f48c81123eb52d60b( 0xff64905f73a67fb594e0f940a8075a860db489ad991e032f48c81123eb52d60b, 0x0000000000000000000000000000000000000000000000000000000000026964, 0000000000000000000000000000000000000000000000000000000000000020, 0000000000000000000000000000000000000000000000000000000000000264, 000000000000000000000000096760f208390250649e3e8763348e783aef5562, 0000000000000000000000000000000000000000000000000000000000000000, 000000000000000000000000000000000000000000000000000369d99ecc462d, 000000000000000000000000000000000000000000000000000001a21d4093b1, 000000000000000000000000c8484d4a6baaaa7c31f411b1362145da109f9b50, 000000000000000000000000c8484d4a6baaaa7c31f411b1362145da109f9b50, 000000000000000000000000000000000000000000000000000000000006b757, 0000000000000000000000000000000000000000000000000000000081de3fe4, 0000000000000000000000000000000000000000000000000000000000000144, 2e567b36000000000000000000000000a0b86991c6218b36c1d19d4a2e9eb0ce, 3606eb48000000000000000000000000c8484d4a6baaaa7c31f411b1362145da, 109f9b50000000000000000000000000c8484d4a6baaaa7c31f411b1362145da, 109f9b500000000000000000000000000000000000000000000000000000000b, 90d3f1b100000000000000000000000000000000000000000000000000000000, 000000a000000000000000000000000000000000000000000000000000000000, 0000008000000000000000000000000000000000000000000000000000000000, 0000004000000000000000000000000000000000000000000000000000000000, 0000006000000000000000000000000000000000000000000000000000000000, 0000000000000000000000000000000000000000000000000000000000000000, 0000000000000000000000000000000000000000000000000000000000000000 )
134 TransparentUpgradeableProxy.0xc1d1490cf25c3b40d600dfb27c7680340ed1ab901b7e8f3551280968a3b372b0( 0xc1d1490cf25c3b40d600dfb27c7680340ed1ab901b7e8f3551280968a3b372b0, 0x000000000000000000000000c8484d4a6baaaa7c31f411b1362145da109f9b50, 0x000000000000000000000000096760f208390250649e3e8763348e783aef5562, 0x0000000000000000000000000000000000000000000000000000000000026964, 0000000000000000000000000000000000000000000000000000000000000020, 0000000000000000000000000000000000000000000000000000000000000144, 2e567b36000000000000000000000000a0b86991c6218b36c1d19d4a2e9eb0ce, 3606eb48000000000000000000000000c8484d4a6baaaa7c31f411b1362145da, 109f9b50000000000000000000000000c8484d4a6baaaa7c31f411b1362145da, 109f9b500000000000000000000000000000000000000000000000000000000b, 90d3f1b100000000000000000000000000000000000000000000000000000000, 000000a000000000000000000000000000000000000000000000000000000000, 0000008000000000000000000000000000000000000000000000000000000000, 0000004000000000000000000000000000000000000000000000000000000000, 0000006000000000000000000000000000000000000000000000000000000000, 0000000000000000000000000000000000000000000000000000000000000000, 0000000000000000000000000000000000000000000000000000000000000000 )
135 TransparentUpgradeableProxy.0xb8910b9960c443aac3240b98585384e3a6f109fbf6969e264c3f183d69aba7e1( 0xb8910b9960c443aac3240b98585384e3a6f109fbf6969e264c3f183d69aba7e1, 0x000000000000000000000000c8484d4a6baaaa7c31f411b1362145da109f9b50, 0x000000000000000000000000c8484d4a6baaaa7c31f411b1362145da109f9b50, 0x0000000000000000000000000000000000000000000000000000000000026964, 000000000000000000000000a0b86991c6218b36c1d19d4a2e9eb0ce3606eb48, 0000000000000000000000000000000000000000000000000000000b90d3f1b1 )

Account State Difference:

  Address   Before After State Difference Code
0x011B6E24...BBc96D515
(Arbitrum: Old Bridge)
293,313.972462546023952431 Eth293,313.973423354347091548 Eth0.000960808323139117
(F2Pool Old)
6,185.168189335082174748 Eth6,185.168489200082174748 Eth0.000299865
0xA0b86991...E3606eB48
0xc8484D4A...A109F9B50
0.425002006686365818 Eth
Nonce: 663
0.392508676105852971 Eth
Nonce: 664
0.032493330580512847

Execution Trace

ETH 0.000960808323139117 TransparentUpgradeableProxy.d2ce7d65( )
  • ETH 0.000960808323139117 L1GatewayRouter.outboundTransfer( _token=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48, _to=0xc8484D4A6BaAaA7C31f411b1362145dA109F9B50, _amount=49674449329, _maxGas=440151, _gasPriceBid=2178826212, _data=0x000000000000000000000000000000000000000000000000000001A21D4093B100000000000000000000000000000000000000000000000000000000000000400000000000000000000000000000000000000000000000000000000000000000 ) => ( 0x0000000000000000000000000000000000000000000000000000000000026964 )
    • ETH 0.000960808323139117 TransparentUpgradeableProxy.d2ce7d65( )
      • ETH 0.000960808323139117 L1CustomGateway.outboundTransfer( _l1Token=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48, _to=0xc8484D4A6BaAaA7C31f411b1362145dA109F9B50, _amount=49674449329, _maxGas=440151, _gasPriceBid=2178826212, _data=0x000000000000000000000000C8484D4A6BAAAA7C31F411B1362145DA109F9B5000000000000000000000000000000000000000000000000000000000000000400000000000000000000000000000000000000000000000000000000000000060000000000000000000000000000000000000000000000000000001A21D4093B100000000000000000000000000000000000000000000000000000000000000400000000000000000000000000000000000000000000000000000000000000000 ) => ( res=0x0000000000000000000000000000000000000000000000000000000000026964 )
        • FiatTokenProxy.70a08231( )
          • FiatTokenV2_1.balanceOf( account=0xcEe284F754E854890e311e3280b767F80797180d ) => ( 242844313761590 )
          • FiatTokenProxy.23b872dd( )
            • FiatTokenV2_1.transferFrom( from=0xc8484D4A6BaAaA7C31f411b1362145dA109F9B50, to=0xcEe284F754E854890e311e3280b767F80797180d, value=49674449329 ) => ( True )
            • FiatTokenProxy.70a08231( )
              • FiatTokenV2_1.balanceOf( account=0xcEe284F754E854890e311e3280b767F80797180d ) => ( 242893988210919 )
              • ETH 0.000960808323139117 TransparentUpgradeableProxy.679b6ded( )
                • ETH 0.000960808323139117 Inbox.createRetryableTicket( destAddr=0x096760F208390250649E3e8763348E783AEF5562, l2CallValue=0, maxSubmissionCost=1795787101105, excessFeeRefundAddress=0xc8484D4A6BaAaA7C31f411b1362145dA109F9B50, callValueRefundAddress=0xc8484D4A6BaAaA7C31f411b1362145dA109F9B50, maxGas=440151, gasPriceBid=2178826212, data=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
                  • ETH 0.000960808323139117 TransparentUpgradeableProxy.02bbfad1( )
                    File 1 of 9: TransparentUpgradeableProxy
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "./UpgradeableProxy.sol";
                    /**
                     * @dev This contract implements a proxy that is upgradeable by an admin.
                     *
                     * To avoid https://medium.com/nomic-labs-blog/malicious-backdoors-in-ethereum-proxies-62629adf3357[proxy selector
                     * clashing], which can potentially be used in an attack, this contract uses the
                     * https://blog.openzeppelin.com/the-transparent-proxy-pattern/[transparent proxy pattern]. This pattern implies two
                     * things that go hand in hand:
                     *
                     * 1. If any account other than the admin calls the proxy, the call will be forwarded to the implementation, even if
                     * that call matches one of the admin functions exposed by the proxy itself.
                     * 2. If the admin calls the proxy, it can access the admin functions, but its calls will never be forwarded to the
                     * implementation. If the admin tries to call a function on the implementation it will fail with an error that says
                     * "admin cannot fallback to proxy target".
                     *
                     * These properties mean that the admin account can only be used for admin actions like upgrading the proxy or changing
                     * the admin, so it's best if it's a dedicated account that is not used for anything else. This will avoid headaches due
                     * to sudden errors when trying to call a function from the proxy implementation.
                     *
                     * Our recommendation is for the dedicated account to be an instance of the {ProxyAdmin} contract. If set up this way,
                     * you should think of the `ProxyAdmin` instance as the real administrative interface of your proxy.
                     */
                    contract TransparentUpgradeableProxy is UpgradeableProxy {
                        /**
                         * @dev Initializes an upgradeable proxy managed by `_admin`, backed by the implementation at `_logic`, and
                         * optionally initialized with `_data` as explained in {UpgradeableProxy-constructor}.
                         */
                        constructor(address _logic, address admin_, bytes memory _data) public payable UpgradeableProxy(_logic, _data) {
                            assert(_ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
                            _setAdmin(admin_);
                        }
                        /**
                         * @dev Emitted when the admin account has changed.
                         */
                        event AdminChanged(address previousAdmin, address newAdmin);
                        /**
                         * @dev Storage slot with the admin of the contract.
                         * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
                         * validated in the constructor.
                         */
                        bytes32 private constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
                        /**
                         * @dev Modifier used internally that will delegate the call to the implementation unless the sender is the admin.
                         */
                        modifier ifAdmin() {
                            if (msg.sender == _admin()) {
                                _;
                            } else {
                                _fallback();
                            }
                        }
                        /**
                         * @dev Returns the current admin.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyAdmin}.
                         *
                         * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
                         * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
                         * `0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103`
                         */
                        function admin() external ifAdmin returns (address admin_) {
                            admin_ = _admin();
                        }
                        /**
                         * @dev Returns the current implementation.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyImplementation}.
                         *
                         * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
                         * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
                         * `0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc`
                         */
                        function implementation() external ifAdmin returns (address implementation_) {
                            implementation_ = _implementation();
                        }
                        /**
                         * @dev Changes the admin of the proxy.
                         *
                         * Emits an {AdminChanged} event.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-changeProxyAdmin}.
                         */
                        function changeAdmin(address newAdmin) external virtual ifAdmin {
                            require(newAdmin != address(0), "TransparentUpgradeableProxy: new admin is the zero address");
                            emit AdminChanged(_admin(), newAdmin);
                            _setAdmin(newAdmin);
                        }
                        /**
                         * @dev Upgrade the implementation of the proxy.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-upgrade}.
                         */
                        function upgradeTo(address newImplementation) external virtual ifAdmin {
                            _upgradeTo(newImplementation);
                        }
                        /**
                         * @dev Upgrade the implementation of the proxy, and then call a function from the new implementation as specified
                         * by `data`, which should be an encoded function call. This is useful to initialize new storage variables in the
                         * proxied contract.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-upgradeAndCall}.
                         */
                        function upgradeToAndCall(address newImplementation, bytes calldata data) external payable virtual ifAdmin {
                            _upgradeTo(newImplementation);
                            Address.functionDelegateCall(newImplementation, data);
                        }
                        /**
                         * @dev Returns the current admin.
                         */
                        function _admin() internal view virtual returns (address adm) {
                            bytes32 slot = _ADMIN_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                adm := sload(slot)
                            }
                        }
                        /**
                         * @dev Stores a new address in the EIP1967 admin slot.
                         */
                        function _setAdmin(address newAdmin) private {
                            bytes32 slot = _ADMIN_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                sstore(slot, newAdmin)
                            }
                        }
                        /**
                         * @dev Makes sure the admin cannot access the fallback function. See {Proxy-_beforeFallback}.
                         */
                        function _beforeFallback() internal virtual override {
                            require(msg.sender != _admin(), "TransparentUpgradeableProxy: admin cannot fallback to proxy target");
                            super._beforeFallback();
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "./Proxy.sol";
                    import "../utils/Address.sol";
                    /**
                     * @dev This contract implements an upgradeable proxy. It is upgradeable because calls are delegated to an
                     * implementation address that can be changed. This address is stored in storage in the location specified by
                     * https://eips.ethereum.org/EIPS/eip-1967[EIP1967], so that it doesn't conflict with the storage layout of the
                     * implementation behind the proxy.
                     *
                     * Upgradeability is only provided internally through {_upgradeTo}. For an externally upgradeable proxy see
                     * {TransparentUpgradeableProxy}.
                     */
                    contract UpgradeableProxy is Proxy {
                        /**
                         * @dev Initializes the upgradeable proxy with an initial implementation specified by `_logic`.
                         *
                         * If `_data` is nonempty, it's used as data in a delegate call to `_logic`. This will typically be an encoded
                         * function call, and allows initializating the storage of the proxy like a Solidity constructor.
                         */
                        constructor(address _logic, bytes memory _data) public payable {
                            assert(_IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
                            _setImplementation(_logic);
                            if(_data.length > 0) {
                                Address.functionDelegateCall(_logic, _data);
                            }
                        }
                        /**
                         * @dev Emitted when the implementation is upgraded.
                         */
                        event Upgraded(address indexed implementation);
                        /**
                         * @dev Storage slot with the address of the current implementation.
                         * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
                         * validated in the constructor.
                         */
                        bytes32 private constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
                        /**
                         * @dev Returns the current implementation address.
                         */
                        function _implementation() internal view virtual override returns (address impl) {
                            bytes32 slot = _IMPLEMENTATION_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                impl := sload(slot)
                            }
                        }
                        /**
                         * @dev Upgrades the proxy to a new implementation.
                         *
                         * Emits an {Upgraded} event.
                         */
                        function _upgradeTo(address newImplementation) internal virtual {
                            _setImplementation(newImplementation);
                            emit Upgraded(newImplementation);
                        }
                        /**
                         * @dev Stores a new address in the EIP1967 implementation slot.
                         */
                        function _setImplementation(address newImplementation) private {
                            require(Address.isContract(newImplementation), "UpgradeableProxy: new implementation is not a contract");
                            bytes32 slot = _IMPLEMENTATION_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                sstore(slot, newImplementation)
                            }
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /**
                     * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
                     * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
                     * be specified by overriding the virtual {_implementation} function.
                     *
                     * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
                     * different contract through the {_delegate} function.
                     *
                     * The success and return data of the delegated call will be returned back to the caller of the proxy.
                     */
                    abstract contract Proxy {
                        /**
                         * @dev Delegates the current call to `implementation`.
                         *
                         * This function does not return to its internall call site, it will return directly to the external caller.
                         */
                        function _delegate(address implementation) internal virtual {
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                // Copy msg.data. We take full control of memory in this inline assembly
                                // block because it will not return to Solidity code. We overwrite the
                                // Solidity scratch pad at memory position 0.
                                calldatacopy(0, 0, calldatasize())
                                // Call the implementation.
                                // out and outsize are 0 because we don't know the size yet.
                                let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)
                                // Copy the returned data.
                                returndatacopy(0, 0, returndatasize())
                                switch result
                                // delegatecall returns 0 on error.
                                case 0 { revert(0, returndatasize()) }
                                default { return(0, returndatasize()) }
                            }
                        }
                        /**
                         * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
                         * and {_fallback} should delegate.
                         */
                        function _implementation() internal view virtual returns (address);
                        /**
                         * @dev Delegates the current call to the address returned by `_implementation()`.
                         *
                         * This function does not return to its internall call site, it will return directly to the external caller.
                         */
                        function _fallback() internal virtual {
                            _beforeFallback();
                            _delegate(_implementation());
                        }
                        /**
                         * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
                         * function in the contract matches the call data.
                         */
                        fallback () external payable virtual {
                            _fallback();
                        }
                        /**
                         * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
                         * is empty.
                         */
                        receive () external payable virtual {
                            _fallback();
                        }
                        /**
                         * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
                         * call, or as part of the Solidity `fallback` or `receive` functions.
                         *
                         * If overriden should call `super._beforeFallback()`.
                         */
                        function _beforeFallback() internal virtual {
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.2 <0.8.0;
                    /**
                     * @dev Collection of functions related to the address type
                     */
                    library Address {
                        /**
                         * @dev Returns true if `account` is a contract.
                         *
                         * [IMPORTANT]
                         * ====
                         * It is unsafe to assume that an address for which this function returns
                         * false is an externally-owned account (EOA) and not a contract.
                         *
                         * Among others, `isContract` will return false for the following
                         * types of addresses:
                         *
                         *  - an externally-owned account
                         *  - a contract in construction
                         *  - an address where a contract will be created
                         *  - an address where a contract lived, but was destroyed
                         * ====
                         */
                        function isContract(address account) internal view returns (bool) {
                            // This method relies on extcodesize, which returns 0 for contracts in
                            // construction, since the code is only stored at the end of the
                            // constructor execution.
                            uint256 size;
                            // solhint-disable-next-line no-inline-assembly
                            assembly { size := extcodesize(account) }
                            return size > 0;
                        }
                        /**
                         * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
                         * `recipient`, forwarding all available gas and reverting on errors.
                         *
                         * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
                         * of certain opcodes, possibly making contracts go over the 2300 gas limit
                         * imposed by `transfer`, making them unable to receive funds via
                         * `transfer`. {sendValue} removes this limitation.
                         *
                         * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
                         *
                         * IMPORTANT: because control is transferred to `recipient`, care must be
                         * taken to not create reentrancy vulnerabilities. Consider using
                         * {ReentrancyGuard} or the
                         * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
                         */
                        function sendValue(address payable recipient, uint256 amount) internal {
                            require(address(this).balance >= amount, "Address: insufficient balance");
                            // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
                            (bool success, ) = recipient.call{ value: amount }("");
                            require(success, "Address: unable to send value, recipient may have reverted");
                        }
                        /**
                         * @dev Performs a Solidity function call using a low level `call`. A
                         * plain`call` is an unsafe replacement for a function call: use this
                         * function instead.
                         *
                         * If `target` reverts with a revert reason, it is bubbled up by this
                         * function (like regular Solidity function calls).
                         *
                         * Returns the raw returned data. To convert to the expected return value,
                         * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
                         *
                         * Requirements:
                         *
                         * - `target` must be a contract.
                         * - calling `target` with `data` must not revert.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                          return functionCall(target, data, "Address: low-level call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
                         * `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, 0, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but also transferring `value` wei to `target`.
                         *
                         * Requirements:
                         *
                         * - the calling contract must have an ETH balance of at least `value`.
                         * - the called Solidity function must be `payable`.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
                         * with `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
                            require(address(this).balance >= value, "Address: insufficient balance for call");
                            require(isContract(target), "Address: call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.call{ value: value }(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                            return functionStaticCall(target, data, "Address: low-level static call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
                            require(isContract(target), "Address: static call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.staticcall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                            return functionDelegateCall(target, data, "Address: low-level delegate call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            require(isContract(target), "Address: delegate call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.delegatecall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
                            if (success) {
                                return returndata;
                            } else {
                                // Look for revert reason and bubble it up if present
                                if (returndata.length > 0) {
                                    // The easiest way to bubble the revert reason is using memory via assembly
                                    // solhint-disable-next-line no-inline-assembly
                                    assembly {
                                        let returndata_size := mload(returndata)
                                        revert(add(32, returndata), returndata_size)
                                    }
                                } else {
                                    revert(errorMessage);
                                }
                            }
                        }
                    }
                    

                    File 2 of 9: FiatTokenProxy
                    pragma solidity ^0.4.24;
                    
                    // File: zos-lib/contracts/upgradeability/Proxy.sol
                    
                    /**
                     * @title Proxy
                     * @dev Implements delegation of calls to other contracts, with proper
                     * forwarding of return values and bubbling of failures.
                     * It defines a fallback function that delegates all calls to the address
                     * returned by the abstract _implementation() internal function.
                     */
                    contract Proxy {
                      /**
                       * @dev Fallback function.
                       * Implemented entirely in `_fallback`.
                       */
                      function () payable external {
                        _fallback();
                      }
                    
                      /**
                       * @return The Address of the implementation.
                       */
                      function _implementation() internal view returns (address);
                    
                      /**
                       * @dev Delegates execution to an implementation contract.
                       * This is a low level function that doesn't return to its internal call site.
                       * It will return to the external caller whatever the implementation returns.
                       * @param implementation Address to delegate.
                       */
                      function _delegate(address implementation) internal {
                        assembly {
                          // Copy msg.data. We take full control of memory in this inline assembly
                          // block because it will not return to Solidity code. We overwrite the
                          // Solidity scratch pad at memory position 0.
                          calldatacopy(0, 0, calldatasize)
                    
                          // Call the implementation.
                          // out and outsize are 0 because we don't know the size yet.
                          let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)
                    
                          // Copy the returned data.
                          returndatacopy(0, 0, returndatasize)
                    
                          switch result
                          // delegatecall returns 0 on error.
                          case 0 { revert(0, returndatasize) }
                          default { return(0, returndatasize) }
                        }
                      }
                    
                      /**
                       * @dev Function that is run as the first thing in the fallback function.
                       * Can be redefined in derived contracts to add functionality.
                       * Redefinitions must call super._willFallback().
                       */
                      function _willFallback() internal {
                      }
                    
                      /**
                       * @dev fallback implementation.
                       * Extracted to enable manual triggering.
                       */
                      function _fallback() internal {
                        _willFallback();
                        _delegate(_implementation());
                      }
                    }
                    
                    // File: openzeppelin-solidity/contracts/AddressUtils.sol
                    
                    /**
                     * Utility library of inline functions on addresses
                     */
                    library AddressUtils {
                    
                      /**
                       * Returns whether the target address is a contract
                       * @dev This function will return false if invoked during the constructor of a contract,
                       * as the code is not actually created until after the constructor finishes.
                       * @param addr address to check
                       * @return whether the target address is a contract
                       */
                      function isContract(address addr) internal view returns (bool) {
                        uint256 size;
                        // XXX Currently there is no better way to check if there is a contract in an address
                        // than to check the size of the code at that address.
                        // See https://ethereum.stackexchange.com/a/14016/36603
                        // for more details about how this works.
                        // TODO Check this again before the Serenity release, because all addresses will be
                        // contracts then.
                        // solium-disable-next-line security/no-inline-assembly
                        assembly { size := extcodesize(addr) }
                        return size > 0;
                      }
                    
                    }
                    
                    // File: zos-lib/contracts/upgradeability/UpgradeabilityProxy.sol
                    
                    /**
                     * @title UpgradeabilityProxy
                     * @dev This contract implements a proxy that allows to change the
                     * implementation address to which it will delegate.
                     * Such a change is called an implementation upgrade.
                     */
                    contract UpgradeabilityProxy is Proxy {
                      /**
                       * @dev Emitted when the implementation is upgraded.
                       * @param implementation Address of the new implementation.
                       */
                      event Upgraded(address implementation);
                    
                      /**
                       * @dev Storage slot with the address of the current implementation.
                       * This is the keccak-256 hash of "org.zeppelinos.proxy.implementation", and is
                       * validated in the constructor.
                       */
                      bytes32 private constant IMPLEMENTATION_SLOT = 0x7050c9e0f4ca769c69bd3a8ef740bc37934f8e2c036e5a723fd8ee048ed3f8c3;
                    
                      /**
                       * @dev Contract constructor.
                       * @param _implementation Address of the initial implementation.
                       */
                      constructor(address _implementation) public {
                        assert(IMPLEMENTATION_SLOT == keccak256("org.zeppelinos.proxy.implementation"));
                    
                        _setImplementation(_implementation);
                      }
                    
                      /**
                       * @dev Returns the current implementation.
                       * @return Address of the current implementation
                       */
                      function _implementation() internal view returns (address impl) {
                        bytes32 slot = IMPLEMENTATION_SLOT;
                        assembly {
                          impl := sload(slot)
                        }
                      }
                    
                      /**
                       * @dev Upgrades the proxy to a new implementation.
                       * @param newImplementation Address of the new implementation.
                       */
                      function _upgradeTo(address newImplementation) internal {
                        _setImplementation(newImplementation);
                        emit Upgraded(newImplementation);
                      }
                    
                      /**
                       * @dev Sets the implementation address of the proxy.
                       * @param newImplementation Address of the new implementation.
                       */
                      function _setImplementation(address newImplementation) private {
                        require(AddressUtils.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");
                    
                        bytes32 slot = IMPLEMENTATION_SLOT;
                    
                        assembly {
                          sstore(slot, newImplementation)
                        }
                      }
                    }
                    
                    // File: zos-lib/contracts/upgradeability/AdminUpgradeabilityProxy.sol
                    
                    /**
                     * @title AdminUpgradeabilityProxy
                     * @dev This contract combines an upgradeability proxy with an authorization
                     * mechanism for administrative tasks.
                     * All external functions in this contract must be guarded by the
                     * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
                     * feature proposal that would enable this to be done automatically.
                     */
                    contract AdminUpgradeabilityProxy is UpgradeabilityProxy {
                      /**
                       * @dev Emitted when the administration has been transferred.
                       * @param previousAdmin Address of the previous admin.
                       * @param newAdmin Address of the new admin.
                       */
                      event AdminChanged(address previousAdmin, address newAdmin);
                    
                      /**
                       * @dev Storage slot with the admin of the contract.
                       * This is the keccak-256 hash of "org.zeppelinos.proxy.admin", and is
                       * validated in the constructor.
                       */
                      bytes32 private constant ADMIN_SLOT = 0x10d6a54a4754c8869d6886b5f5d7fbfa5b4522237ea5c60d11bc4e7a1ff9390b;
                    
                      /**
                       * @dev Modifier to check whether the `msg.sender` is the admin.
                       * If it is, it will run the function. Otherwise, it will delegate the call
                       * to the implementation.
                       */
                      modifier ifAdmin() {
                        if (msg.sender == _admin()) {
                          _;
                        } else {
                          _fallback();
                        }
                      }
                    
                      /**
                       * Contract constructor.
                       * It sets the `msg.sender` as the proxy administrator.
                       * @param _implementation address of the initial implementation.
                       */
                      constructor(address _implementation) UpgradeabilityProxy(_implementation) public {
                        assert(ADMIN_SLOT == keccak256("org.zeppelinos.proxy.admin"));
                    
                        _setAdmin(msg.sender);
                      }
                    
                      /**
                       * @return The address of the proxy admin.
                       */
                      function admin() external view ifAdmin returns (address) {
                        return _admin();
                      }
                    
                      /**
                       * @return The address of the implementation.
                       */
                      function implementation() external view ifAdmin returns (address) {
                        return _implementation();
                      }
                    
                      /**
                       * @dev Changes the admin of the proxy.
                       * Only the current admin can call this function.
                       * @param newAdmin Address to transfer proxy administration to.
                       */
                      function changeAdmin(address newAdmin) external ifAdmin {
                        require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
                        emit AdminChanged(_admin(), newAdmin);
                        _setAdmin(newAdmin);
                      }
                    
                      /**
                       * @dev Upgrade the backing implementation of the proxy.
                       * Only the admin can call this function.
                       * @param newImplementation Address of the new implementation.
                       */
                      function upgradeTo(address newImplementation) external ifAdmin {
                        _upgradeTo(newImplementation);
                      }
                    
                      /**
                       * @dev Upgrade the backing implementation of the proxy and call a function
                       * on the new implementation.
                       * This is useful to initialize the proxied contract.
                       * @param newImplementation Address of the new implementation.
                       * @param data Data to send as msg.data in the low level call.
                       * It should include the signature and the parameters of the function to be
                       * called, as described in
                       * https://solidity.readthedocs.io/en/develop/abi-spec.html#function-selector-and-argument-encoding.
                       */
                      function upgradeToAndCall(address newImplementation, bytes data) payable external ifAdmin {
                        _upgradeTo(newImplementation);
                        require(address(this).call.value(msg.value)(data));
                      }
                    
                      /**
                       * @return The admin slot.
                       */
                      function _admin() internal view returns (address adm) {
                        bytes32 slot = ADMIN_SLOT;
                        assembly {
                          adm := sload(slot)
                        }
                      }
                    
                      /**
                       * @dev Sets the address of the proxy admin.
                       * @param newAdmin Address of the new proxy admin.
                       */
                      function _setAdmin(address newAdmin) internal {
                        bytes32 slot = ADMIN_SLOT;
                    
                        assembly {
                          sstore(slot, newAdmin)
                        }
                      }
                    
                      /**
                       * @dev Only fall back when the sender is not the admin.
                       */
                      function _willFallback() internal {
                        require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
                        super._willFallback();
                      }
                    }
                    
                    // File: contracts/FiatTokenProxy.sol
                    
                    /**
                    * Copyright CENTRE SECZ 2018
                    *
                    * Permission is hereby granted, free of charge, to any person obtaining a copy 
                    * of this software and associated documentation files (the "Software"), to deal 
                    * in the Software without restriction, including without limitation the rights 
                    * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
                    * copies of the Software, and to permit persons to whom the Software is furnished to 
                    * do so, subject to the following conditions:
                    *
                    * The above copyright notice and this permission notice shall be included in all 
                    * copies or substantial portions of the Software.
                    *
                    * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
                    * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
                    * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
                    * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
                    * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 
                    * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
                    */
                    
                    pragma solidity ^0.4.24;
                    
                    
                    /**
                     * @title FiatTokenProxy
                     * @dev This contract proxies FiatToken calls and enables FiatToken upgrades
                    */ 
                    contract FiatTokenProxy is AdminUpgradeabilityProxy {
                        constructor(address _implementation) public AdminUpgradeabilityProxy(_implementation) {
                        }
                    }

                    File 3 of 9: TransparentUpgradeableProxy
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /**
                     * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
                     * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
                     * be specified by overriding the virtual {_implementation} function.
                     *
                     * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
                     * different contract through the {_delegate} function.
                     *
                     * The success and return data of the delegated call will be returned back to the caller of the proxy.
                     */
                    abstract contract Proxy {
                        /**
                         * @dev Delegates the current call to `implementation`.
                         *
                         * This function does not return to its internall call site, it will return directly to the external caller.
                         */
                        function _delegate(address implementation) internal virtual {
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                // Copy msg.data. We take full control of memory in this inline assembly
                                // block because it will not return to Solidity code. We overwrite the
                                // Solidity scratch pad at memory position 0.
                                calldatacopy(0, 0, calldatasize())
                                // Call the implementation.
                                // out and outsize are 0 because we don't know the size yet.
                                let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)
                                // Copy the returned data.
                                returndatacopy(0, 0, returndatasize())
                                switch result
                                // delegatecall returns 0 on error.
                                case 0 { revert(0, returndatasize()) }
                                default { return(0, returndatasize()) }
                            }
                        }
                        /**
                         * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
                         * and {_fallback} should delegate.
                         */
                        function _implementation() internal view virtual returns (address);
                        /**
                         * @dev Delegates the current call to the address returned by `_implementation()`.
                         *
                         * This function does not return to its internall call site, it will return directly to the external caller.
                         */
                        function _fallback() internal virtual {
                            _beforeFallback();
                            _delegate(_implementation());
                        }
                        /**
                         * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
                         * function in the contract matches the call data.
                         */
                        fallback () external payable virtual {
                            _fallback();
                        }
                        /**
                         * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
                         * is empty.
                         */
                        receive () external payable virtual {
                            _fallback();
                        }
                        /**
                         * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
                         * call, or as part of the Solidity `fallback` or `receive` functions.
                         *
                         * If overriden should call `super._beforeFallback()`.
                         */
                        function _beforeFallback() internal virtual {
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "./UpgradeableProxy.sol";
                    /**
                     * @dev This contract implements a proxy that is upgradeable by an admin.
                     *
                     * To avoid https://medium.com/nomic-labs-blog/malicious-backdoors-in-ethereum-proxies-62629adf3357[proxy selector
                     * clashing], which can potentially be used in an attack, this contract uses the
                     * https://blog.openzeppelin.com/the-transparent-proxy-pattern/[transparent proxy pattern]. This pattern implies two
                     * things that go hand in hand:
                     *
                     * 1. If any account other than the admin calls the proxy, the call will be forwarded to the implementation, even if
                     * that call matches one of the admin functions exposed by the proxy itself.
                     * 2. If the admin calls the proxy, it can access the admin functions, but its calls will never be forwarded to the
                     * implementation. If the admin tries to call a function on the implementation it will fail with an error that says
                     * "admin cannot fallback to proxy target".
                     *
                     * These properties mean that the admin account can only be used for admin actions like upgrading the proxy or changing
                     * the admin, so it's best if it's a dedicated account that is not used for anything else. This will avoid headaches due
                     * to sudden errors when trying to call a function from the proxy implementation.
                     *
                     * Our recommendation is for the dedicated account to be an instance of the {ProxyAdmin} contract. If set up this way,
                     * you should think of the `ProxyAdmin` instance as the real administrative interface of your proxy.
                     */
                    contract TransparentUpgradeableProxy is UpgradeableProxy {
                        /**
                         * @dev Initializes an upgradeable proxy managed by `_admin`, backed by the implementation at `_logic`, and
                         * optionally initialized with `_data` as explained in {UpgradeableProxy-constructor}.
                         */
                        constructor(address _logic, address admin_, bytes memory _data) public payable UpgradeableProxy(_logic, _data) {
                            assert(_ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
                            _setAdmin(admin_);
                        }
                        /**
                         * @dev Emitted when the admin account has changed.
                         */
                        event AdminChanged(address previousAdmin, address newAdmin);
                        /**
                         * @dev Storage slot with the admin of the contract.
                         * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
                         * validated in the constructor.
                         */
                        bytes32 private constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
                        /**
                         * @dev Modifier used internally that will delegate the call to the implementation unless the sender is the admin.
                         */
                        modifier ifAdmin() {
                            if (msg.sender == _admin()) {
                                _;
                            } else {
                                _fallback();
                            }
                        }
                        /**
                         * @dev Returns the current admin.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyAdmin}.
                         *
                         * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
                         * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
                         * `0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103`
                         */
                        function admin() external ifAdmin returns (address admin_) {
                            admin_ = _admin();
                        }
                        /**
                         * @dev Returns the current implementation.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyImplementation}.
                         *
                         * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
                         * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
                         * `0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc`
                         */
                        function implementation() external ifAdmin returns (address implementation_) {
                            implementation_ = _implementation();
                        }
                        /**
                         * @dev Changes the admin of the proxy.
                         *
                         * Emits an {AdminChanged} event.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-changeProxyAdmin}.
                         */
                        function changeAdmin(address newAdmin) external virtual ifAdmin {
                            require(newAdmin != address(0), "TransparentUpgradeableProxy: new admin is the zero address");
                            emit AdminChanged(_admin(), newAdmin);
                            _setAdmin(newAdmin);
                        }
                        /**
                         * @dev Upgrade the implementation of the proxy.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-upgrade}.
                         */
                        function upgradeTo(address newImplementation) external virtual ifAdmin {
                            _upgradeTo(newImplementation);
                        }
                        /**
                         * @dev Upgrade the implementation of the proxy, and then call a function from the new implementation as specified
                         * by `data`, which should be an encoded function call. This is useful to initialize new storage variables in the
                         * proxied contract.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-upgradeAndCall}.
                         */
                        function upgradeToAndCall(address newImplementation, bytes calldata data) external payable virtual ifAdmin {
                            _upgradeTo(newImplementation);
                            Address.functionDelegateCall(newImplementation, data);
                        }
                        /**
                         * @dev Returns the current admin.
                         */
                        function _admin() internal view virtual returns (address adm) {
                            bytes32 slot = _ADMIN_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                adm := sload(slot)
                            }
                        }
                        /**
                         * @dev Stores a new address in the EIP1967 admin slot.
                         */
                        function _setAdmin(address newAdmin) private {
                            bytes32 slot = _ADMIN_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                sstore(slot, newAdmin)
                            }
                        }
                        /**
                         * @dev Makes sure the admin cannot access the fallback function. See {Proxy-_beforeFallback}.
                         */
                        function _beforeFallback() internal virtual override {
                            require(msg.sender != _admin(), "TransparentUpgradeableProxy: admin cannot fallback to proxy target");
                            super._beforeFallback();
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "./Proxy.sol";
                    import "../utils/Address.sol";
                    /**
                     * @dev This contract implements an upgradeable proxy. It is upgradeable because calls are delegated to an
                     * implementation address that can be changed. This address is stored in storage in the location specified by
                     * https://eips.ethereum.org/EIPS/eip-1967[EIP1967], so that it doesn't conflict with the storage layout of the
                     * implementation behind the proxy.
                     *
                     * Upgradeability is only provided internally through {_upgradeTo}. For an externally upgradeable proxy see
                     * {TransparentUpgradeableProxy}.
                     */
                    contract UpgradeableProxy is Proxy {
                        /**
                         * @dev Initializes the upgradeable proxy with an initial implementation specified by `_logic`.
                         *
                         * If `_data` is nonempty, it's used as data in a delegate call to `_logic`. This will typically be an encoded
                         * function call, and allows initializating the storage of the proxy like a Solidity constructor.
                         */
                        constructor(address _logic, bytes memory _data) public payable {
                            assert(_IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
                            _setImplementation(_logic);
                            if(_data.length > 0) {
                                Address.functionDelegateCall(_logic, _data);
                            }
                        }
                        /**
                         * @dev Emitted when the implementation is upgraded.
                         */
                        event Upgraded(address indexed implementation);
                        /**
                         * @dev Storage slot with the address of the current implementation.
                         * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
                         * validated in the constructor.
                         */
                        bytes32 private constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
                        /**
                         * @dev Returns the current implementation address.
                         */
                        function _implementation() internal view virtual override returns (address impl) {
                            bytes32 slot = _IMPLEMENTATION_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                impl := sload(slot)
                            }
                        }
                        /**
                         * @dev Upgrades the proxy to a new implementation.
                         *
                         * Emits an {Upgraded} event.
                         */
                        function _upgradeTo(address newImplementation) internal virtual {
                            _setImplementation(newImplementation);
                            emit Upgraded(newImplementation);
                        }
                        /**
                         * @dev Stores a new address in the EIP1967 implementation slot.
                         */
                        function _setImplementation(address newImplementation) private {
                            require(Address.isContract(newImplementation), "UpgradeableProxy: new implementation is not a contract");
                            bytes32 slot = _IMPLEMENTATION_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                sstore(slot, newImplementation)
                            }
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.2 <0.8.0;
                    /**
                     * @dev Collection of functions related to the address type
                     */
                    library Address {
                        /**
                         * @dev Returns true if `account` is a contract.
                         *
                         * [IMPORTANT]
                         * ====
                         * It is unsafe to assume that an address for which this function returns
                         * false is an externally-owned account (EOA) and not a contract.
                         *
                         * Among others, `isContract` will return false for the following
                         * types of addresses:
                         *
                         *  - an externally-owned account
                         *  - a contract in construction
                         *  - an address where a contract will be created
                         *  - an address where a contract lived, but was destroyed
                         * ====
                         */
                        function isContract(address account) internal view returns (bool) {
                            // This method relies on extcodesize, which returns 0 for contracts in
                            // construction, since the code is only stored at the end of the
                            // constructor execution.
                            uint256 size;
                            // solhint-disable-next-line no-inline-assembly
                            assembly { size := extcodesize(account) }
                            return size > 0;
                        }
                        /**
                         * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
                         * `recipient`, forwarding all available gas and reverting on errors.
                         *
                         * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
                         * of certain opcodes, possibly making contracts go over the 2300 gas limit
                         * imposed by `transfer`, making them unable to receive funds via
                         * `transfer`. {sendValue} removes this limitation.
                         *
                         * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
                         *
                         * IMPORTANT: because control is transferred to `recipient`, care must be
                         * taken to not create reentrancy vulnerabilities. Consider using
                         * {ReentrancyGuard} or the
                         * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
                         */
                        function sendValue(address payable recipient, uint256 amount) internal {
                            require(address(this).balance >= amount, "Address: insufficient balance");
                            // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
                            (bool success, ) = recipient.call{ value: amount }("");
                            require(success, "Address: unable to send value, recipient may have reverted");
                        }
                        /**
                         * @dev Performs a Solidity function call using a low level `call`. A
                         * plain`call` is an unsafe replacement for a function call: use this
                         * function instead.
                         *
                         * If `target` reverts with a revert reason, it is bubbled up by this
                         * function (like regular Solidity function calls).
                         *
                         * Returns the raw returned data. To convert to the expected return value,
                         * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
                         *
                         * Requirements:
                         *
                         * - `target` must be a contract.
                         * - calling `target` with `data` must not revert.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                          return functionCall(target, data, "Address: low-level call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
                         * `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, 0, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but also transferring `value` wei to `target`.
                         *
                         * Requirements:
                         *
                         * - the calling contract must have an ETH balance of at least `value`.
                         * - the called Solidity function must be `payable`.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
                         * with `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
                            require(address(this).balance >= value, "Address: insufficient balance for call");
                            require(isContract(target), "Address: call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.call{ value: value }(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                            return functionStaticCall(target, data, "Address: low-level static call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
                            require(isContract(target), "Address: static call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.staticcall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                            return functionDelegateCall(target, data, "Address: low-level delegate call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            require(isContract(target), "Address: delegate call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.delegatecall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
                            if (success) {
                                return returndata;
                            } else {
                                // Look for revert reason and bubble it up if present
                                if (returndata.length > 0) {
                                    // The easiest way to bubble the revert reason is using memory via assembly
                                    // solhint-disable-next-line no-inline-assembly
                                    assembly {
                                        let returndata_size := mload(returndata)
                                        revert(add(32, returndata), returndata_size)
                                    }
                                } else {
                                    revert(errorMessage);
                                }
                            }
                        }
                    }
                    

                    File 4 of 9: TransparentUpgradeableProxy
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /**
                     * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
                     * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
                     * be specified by overriding the virtual {_implementation} function.
                     *
                     * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
                     * different contract through the {_delegate} function.
                     *
                     * The success and return data of the delegated call will be returned back to the caller of the proxy.
                     */
                    abstract contract Proxy {
                        /**
                         * @dev Delegates the current call to `implementation`.
                         *
                         * This function does not return to its internall call site, it will return directly to the external caller.
                         */
                        function _delegate(address implementation) internal virtual {
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                // Copy msg.data. We take full control of memory in this inline assembly
                                // block because it will not return to Solidity code. We overwrite the
                                // Solidity scratch pad at memory position 0.
                                calldatacopy(0, 0, calldatasize())
                                // Call the implementation.
                                // out and outsize are 0 because we don't know the size yet.
                                let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)
                                // Copy the returned data.
                                returndatacopy(0, 0, returndatasize())
                                switch result
                                // delegatecall returns 0 on error.
                                case 0 { revert(0, returndatasize()) }
                                default { return(0, returndatasize()) }
                            }
                        }
                        /**
                         * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
                         * and {_fallback} should delegate.
                         */
                        function _implementation() internal view virtual returns (address);
                        /**
                         * @dev Delegates the current call to the address returned by `_implementation()`.
                         *
                         * This function does not return to its internall call site, it will return directly to the external caller.
                         */
                        function _fallback() internal virtual {
                            _beforeFallback();
                            _delegate(_implementation());
                        }
                        /**
                         * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
                         * function in the contract matches the call data.
                         */
                        fallback () external payable virtual {
                            _fallback();
                        }
                        /**
                         * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
                         * is empty.
                         */
                        receive () external payable virtual {
                            _fallback();
                        }
                        /**
                         * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
                         * call, or as part of the Solidity `fallback` or `receive` functions.
                         *
                         * If overriden should call `super._beforeFallback()`.
                         */
                        function _beforeFallback() internal virtual {
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "./UpgradeableProxy.sol";
                    /**
                     * @dev This contract implements a proxy that is upgradeable by an admin.
                     *
                     * To avoid https://medium.com/nomic-labs-blog/malicious-backdoors-in-ethereum-proxies-62629adf3357[proxy selector
                     * clashing], which can potentially be used in an attack, this contract uses the
                     * https://blog.openzeppelin.com/the-transparent-proxy-pattern/[transparent proxy pattern]. This pattern implies two
                     * things that go hand in hand:
                     *
                     * 1. If any account other than the admin calls the proxy, the call will be forwarded to the implementation, even if
                     * that call matches one of the admin functions exposed by the proxy itself.
                     * 2. If the admin calls the proxy, it can access the admin functions, but its calls will never be forwarded to the
                     * implementation. If the admin tries to call a function on the implementation it will fail with an error that says
                     * "admin cannot fallback to proxy target".
                     *
                     * These properties mean that the admin account can only be used for admin actions like upgrading the proxy or changing
                     * the admin, so it's best if it's a dedicated account that is not used for anything else. This will avoid headaches due
                     * to sudden errors when trying to call a function from the proxy implementation.
                     *
                     * Our recommendation is for the dedicated account to be an instance of the {ProxyAdmin} contract. If set up this way,
                     * you should think of the `ProxyAdmin` instance as the real administrative interface of your proxy.
                     */
                    contract TransparentUpgradeableProxy is UpgradeableProxy {
                        /**
                         * @dev Initializes an upgradeable proxy managed by `_admin`, backed by the implementation at `_logic`, and
                         * optionally initialized with `_data` as explained in {UpgradeableProxy-constructor}.
                         */
                        constructor(address _logic, address admin_, bytes memory _data) public payable UpgradeableProxy(_logic, _data) {
                            assert(_ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
                            _setAdmin(admin_);
                        }
                        /**
                         * @dev Emitted when the admin account has changed.
                         */
                        event AdminChanged(address previousAdmin, address newAdmin);
                        /**
                         * @dev Storage slot with the admin of the contract.
                         * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
                         * validated in the constructor.
                         */
                        bytes32 private constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
                        /**
                         * @dev Modifier used internally that will delegate the call to the implementation unless the sender is the admin.
                         */
                        modifier ifAdmin() {
                            if (msg.sender == _admin()) {
                                _;
                            } else {
                                _fallback();
                            }
                        }
                        /**
                         * @dev Returns the current admin.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyAdmin}.
                         *
                         * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
                         * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
                         * `0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103`
                         */
                        function admin() external ifAdmin returns (address admin_) {
                            admin_ = _admin();
                        }
                        /**
                         * @dev Returns the current implementation.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyImplementation}.
                         *
                         * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
                         * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
                         * `0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc`
                         */
                        function implementation() external ifAdmin returns (address implementation_) {
                            implementation_ = _implementation();
                        }
                        /**
                         * @dev Changes the admin of the proxy.
                         *
                         * Emits an {AdminChanged} event.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-changeProxyAdmin}.
                         */
                        function changeAdmin(address newAdmin) external virtual ifAdmin {
                            require(newAdmin != address(0), "TransparentUpgradeableProxy: new admin is the zero address");
                            emit AdminChanged(_admin(), newAdmin);
                            _setAdmin(newAdmin);
                        }
                        /**
                         * @dev Upgrade the implementation of the proxy.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-upgrade}.
                         */
                        function upgradeTo(address newImplementation) external virtual ifAdmin {
                            _upgradeTo(newImplementation);
                        }
                        /**
                         * @dev Upgrade the implementation of the proxy, and then call a function from the new implementation as specified
                         * by `data`, which should be an encoded function call. This is useful to initialize new storage variables in the
                         * proxied contract.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-upgradeAndCall}.
                         */
                        function upgradeToAndCall(address newImplementation, bytes calldata data) external payable virtual ifAdmin {
                            _upgradeTo(newImplementation);
                            Address.functionDelegateCall(newImplementation, data);
                        }
                        /**
                         * @dev Returns the current admin.
                         */
                        function _admin() internal view virtual returns (address adm) {
                            bytes32 slot = _ADMIN_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                adm := sload(slot)
                            }
                        }
                        /**
                         * @dev Stores a new address in the EIP1967 admin slot.
                         */
                        function _setAdmin(address newAdmin) private {
                            bytes32 slot = _ADMIN_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                sstore(slot, newAdmin)
                            }
                        }
                        /**
                         * @dev Makes sure the admin cannot access the fallback function. See {Proxy-_beforeFallback}.
                         */
                        function _beforeFallback() internal virtual override {
                            require(msg.sender != _admin(), "TransparentUpgradeableProxy: admin cannot fallback to proxy target");
                            super._beforeFallback();
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "./Proxy.sol";
                    import "../utils/Address.sol";
                    /**
                     * @dev This contract implements an upgradeable proxy. It is upgradeable because calls are delegated to an
                     * implementation address that can be changed. This address is stored in storage in the location specified by
                     * https://eips.ethereum.org/EIPS/eip-1967[EIP1967], so that it doesn't conflict with the storage layout of the
                     * implementation behind the proxy.
                     *
                     * Upgradeability is only provided internally through {_upgradeTo}. For an externally upgradeable proxy see
                     * {TransparentUpgradeableProxy}.
                     */
                    contract UpgradeableProxy is Proxy {
                        /**
                         * @dev Initializes the upgradeable proxy with an initial implementation specified by `_logic`.
                         *
                         * If `_data` is nonempty, it's used as data in a delegate call to `_logic`. This will typically be an encoded
                         * function call, and allows initializating the storage of the proxy like a Solidity constructor.
                         */
                        constructor(address _logic, bytes memory _data) public payable {
                            assert(_IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
                            _setImplementation(_logic);
                            if(_data.length > 0) {
                                Address.functionDelegateCall(_logic, _data);
                            }
                        }
                        /**
                         * @dev Emitted when the implementation is upgraded.
                         */
                        event Upgraded(address indexed implementation);
                        /**
                         * @dev Storage slot with the address of the current implementation.
                         * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
                         * validated in the constructor.
                         */
                        bytes32 private constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
                        /**
                         * @dev Returns the current implementation address.
                         */
                        function _implementation() internal view virtual override returns (address impl) {
                            bytes32 slot = _IMPLEMENTATION_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                impl := sload(slot)
                            }
                        }
                        /**
                         * @dev Upgrades the proxy to a new implementation.
                         *
                         * Emits an {Upgraded} event.
                         */
                        function _upgradeTo(address newImplementation) internal virtual {
                            _setImplementation(newImplementation);
                            emit Upgraded(newImplementation);
                        }
                        /**
                         * @dev Stores a new address in the EIP1967 implementation slot.
                         */
                        function _setImplementation(address newImplementation) private {
                            require(Address.isContract(newImplementation), "UpgradeableProxy: new implementation is not a contract");
                            bytes32 slot = _IMPLEMENTATION_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                sstore(slot, newImplementation)
                            }
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.2 <0.8.0;
                    /**
                     * @dev Collection of functions related to the address type
                     */
                    library Address {
                        /**
                         * @dev Returns true if `account` is a contract.
                         *
                         * [IMPORTANT]
                         * ====
                         * It is unsafe to assume that an address for which this function returns
                         * false is an externally-owned account (EOA) and not a contract.
                         *
                         * Among others, `isContract` will return false for the following
                         * types of addresses:
                         *
                         *  - an externally-owned account
                         *  - a contract in construction
                         *  - an address where a contract will be created
                         *  - an address where a contract lived, but was destroyed
                         * ====
                         */
                        function isContract(address account) internal view returns (bool) {
                            // This method relies on extcodesize, which returns 0 for contracts in
                            // construction, since the code is only stored at the end of the
                            // constructor execution.
                            uint256 size;
                            // solhint-disable-next-line no-inline-assembly
                            assembly { size := extcodesize(account) }
                            return size > 0;
                        }
                        /**
                         * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
                         * `recipient`, forwarding all available gas and reverting on errors.
                         *
                         * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
                         * of certain opcodes, possibly making contracts go over the 2300 gas limit
                         * imposed by `transfer`, making them unable to receive funds via
                         * `transfer`. {sendValue} removes this limitation.
                         *
                         * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
                         *
                         * IMPORTANT: because control is transferred to `recipient`, care must be
                         * taken to not create reentrancy vulnerabilities. Consider using
                         * {ReentrancyGuard} or the
                         * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
                         */
                        function sendValue(address payable recipient, uint256 amount) internal {
                            require(address(this).balance >= amount, "Address: insufficient balance");
                            // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
                            (bool success, ) = recipient.call{ value: amount }("");
                            require(success, "Address: unable to send value, recipient may have reverted");
                        }
                        /**
                         * @dev Performs a Solidity function call using a low level `call`. A
                         * plain`call` is an unsafe replacement for a function call: use this
                         * function instead.
                         *
                         * If `target` reverts with a revert reason, it is bubbled up by this
                         * function (like regular Solidity function calls).
                         *
                         * Returns the raw returned data. To convert to the expected return value,
                         * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
                         *
                         * Requirements:
                         *
                         * - `target` must be a contract.
                         * - calling `target` with `data` must not revert.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                          return functionCall(target, data, "Address: low-level call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
                         * `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, 0, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but also transferring `value` wei to `target`.
                         *
                         * Requirements:
                         *
                         * - the calling contract must have an ETH balance of at least `value`.
                         * - the called Solidity function must be `payable`.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
                         * with `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
                            require(address(this).balance >= value, "Address: insufficient balance for call");
                            require(isContract(target), "Address: call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.call{ value: value }(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                            return functionStaticCall(target, data, "Address: low-level static call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
                            require(isContract(target), "Address: static call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.staticcall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                            return functionDelegateCall(target, data, "Address: low-level delegate call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            require(isContract(target), "Address: delegate call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.delegatecall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
                            if (success) {
                                return returndata;
                            } else {
                                // Look for revert reason and bubble it up if present
                                if (returndata.length > 0) {
                                    // The easiest way to bubble the revert reason is using memory via assembly
                                    // solhint-disable-next-line no-inline-assembly
                                    assembly {
                                        let returndata_size := mload(returndata)
                                        revert(add(32, returndata), returndata_size)
                                    }
                                } else {
                                    revert(errorMessage);
                                }
                            }
                        }
                    }
                    

                    File 5 of 9: TransparentUpgradeableProxy
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "./UpgradeableProxy.sol";
                    /**
                     * @dev This contract implements a proxy that is upgradeable by an admin.
                     *
                     * To avoid https://medium.com/nomic-labs-blog/malicious-backdoors-in-ethereum-proxies-62629adf3357[proxy selector
                     * clashing], which can potentially be used in an attack, this contract uses the
                     * https://blog.openzeppelin.com/the-transparent-proxy-pattern/[transparent proxy pattern]. This pattern implies two
                     * things that go hand in hand:
                     *
                     * 1. If any account other than the admin calls the proxy, the call will be forwarded to the implementation, even if
                     * that call matches one of the admin functions exposed by the proxy itself.
                     * 2. If the admin calls the proxy, it can access the admin functions, but its calls will never be forwarded to the
                     * implementation. If the admin tries to call a function on the implementation it will fail with an error that says
                     * "admin cannot fallback to proxy target".
                     *
                     * These properties mean that the admin account can only be used for admin actions like upgrading the proxy or changing
                     * the admin, so it's best if it's a dedicated account that is not used for anything else. This will avoid headaches due
                     * to sudden errors when trying to call a function from the proxy implementation.
                     *
                     * Our recommendation is for the dedicated account to be an instance of the {ProxyAdmin} contract. If set up this way,
                     * you should think of the `ProxyAdmin` instance as the real administrative interface of your proxy.
                     */
                    contract TransparentUpgradeableProxy is UpgradeableProxy {
                        /**
                         * @dev Initializes an upgradeable proxy managed by `_admin`, backed by the implementation at `_logic`, and
                         * optionally initialized with `_data` as explained in {UpgradeableProxy-constructor}.
                         */
                        constructor(address _logic, address admin_, bytes memory _data) public payable UpgradeableProxy(_logic, _data) {
                            assert(_ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
                            _setAdmin(admin_);
                        }
                        /**
                         * @dev Emitted when the admin account has changed.
                         */
                        event AdminChanged(address previousAdmin, address newAdmin);
                        /**
                         * @dev Storage slot with the admin of the contract.
                         * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
                         * validated in the constructor.
                         */
                        bytes32 private constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
                        /**
                         * @dev Modifier used internally that will delegate the call to the implementation unless the sender is the admin.
                         */
                        modifier ifAdmin() {
                            if (msg.sender == _admin()) {
                                _;
                            } else {
                                _fallback();
                            }
                        }
                        /**
                         * @dev Returns the current admin.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyAdmin}.
                         *
                         * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
                         * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
                         * `0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103`
                         */
                        function admin() external ifAdmin returns (address admin_) {
                            admin_ = _admin();
                        }
                        /**
                         * @dev Returns the current implementation.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyImplementation}.
                         *
                         * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
                         * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
                         * `0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc`
                         */
                        function implementation() external ifAdmin returns (address implementation_) {
                            implementation_ = _implementation();
                        }
                        /**
                         * @dev Changes the admin of the proxy.
                         *
                         * Emits an {AdminChanged} event.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-changeProxyAdmin}.
                         */
                        function changeAdmin(address newAdmin) external virtual ifAdmin {
                            require(newAdmin != address(0), "TransparentUpgradeableProxy: new admin is the zero address");
                            emit AdminChanged(_admin(), newAdmin);
                            _setAdmin(newAdmin);
                        }
                        /**
                         * @dev Upgrade the implementation of the proxy.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-upgrade}.
                         */
                        function upgradeTo(address newImplementation) external virtual ifAdmin {
                            _upgradeTo(newImplementation);
                        }
                        /**
                         * @dev Upgrade the implementation of the proxy, and then call a function from the new implementation as specified
                         * by `data`, which should be an encoded function call. This is useful to initialize new storage variables in the
                         * proxied contract.
                         *
                         * NOTE: Only the admin can call this function. See {ProxyAdmin-upgradeAndCall}.
                         */
                        function upgradeToAndCall(address newImplementation, bytes calldata data) external payable virtual ifAdmin {
                            _upgradeTo(newImplementation);
                            Address.functionDelegateCall(newImplementation, data);
                        }
                        /**
                         * @dev Returns the current admin.
                         */
                        function _admin() internal view virtual returns (address adm) {
                            bytes32 slot = _ADMIN_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                adm := sload(slot)
                            }
                        }
                        /**
                         * @dev Stores a new address in the EIP1967 admin slot.
                         */
                        function _setAdmin(address newAdmin) private {
                            bytes32 slot = _ADMIN_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                sstore(slot, newAdmin)
                            }
                        }
                        /**
                         * @dev Makes sure the admin cannot access the fallback function. See {Proxy-_beforeFallback}.
                         */
                        function _beforeFallback() internal virtual override {
                            require(msg.sender != _admin(), "TransparentUpgradeableProxy: admin cannot fallback to proxy target");
                            super._beforeFallback();
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "./Proxy.sol";
                    import "../utils/Address.sol";
                    /**
                     * @dev This contract implements an upgradeable proxy. It is upgradeable because calls are delegated to an
                     * implementation address that can be changed. This address is stored in storage in the location specified by
                     * https://eips.ethereum.org/EIPS/eip-1967[EIP1967], so that it doesn't conflict with the storage layout of the
                     * implementation behind the proxy.
                     *
                     * Upgradeability is only provided internally through {_upgradeTo}. For an externally upgradeable proxy see
                     * {TransparentUpgradeableProxy}.
                     */
                    contract UpgradeableProxy is Proxy {
                        /**
                         * @dev Initializes the upgradeable proxy with an initial implementation specified by `_logic`.
                         *
                         * If `_data` is nonempty, it's used as data in a delegate call to `_logic`. This will typically be an encoded
                         * function call, and allows initializating the storage of the proxy like a Solidity constructor.
                         */
                        constructor(address _logic, bytes memory _data) public payable {
                            assert(_IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
                            _setImplementation(_logic);
                            if(_data.length > 0) {
                                Address.functionDelegateCall(_logic, _data);
                            }
                        }
                        /**
                         * @dev Emitted when the implementation is upgraded.
                         */
                        event Upgraded(address indexed implementation);
                        /**
                         * @dev Storage slot with the address of the current implementation.
                         * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
                         * validated in the constructor.
                         */
                        bytes32 private constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
                        /**
                         * @dev Returns the current implementation address.
                         */
                        function _implementation() internal view virtual override returns (address impl) {
                            bytes32 slot = _IMPLEMENTATION_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                impl := sload(slot)
                            }
                        }
                        /**
                         * @dev Upgrades the proxy to a new implementation.
                         *
                         * Emits an {Upgraded} event.
                         */
                        function _upgradeTo(address newImplementation) internal virtual {
                            _setImplementation(newImplementation);
                            emit Upgraded(newImplementation);
                        }
                        /**
                         * @dev Stores a new address in the EIP1967 implementation slot.
                         */
                        function _setImplementation(address newImplementation) private {
                            require(Address.isContract(newImplementation), "UpgradeableProxy: new implementation is not a contract");
                            bytes32 slot = _IMPLEMENTATION_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                sstore(slot, newImplementation)
                            }
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /**
                     * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
                     * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
                     * be specified by overriding the virtual {_implementation} function.
                     *
                     * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
                     * different contract through the {_delegate} function.
                     *
                     * The success and return data of the delegated call will be returned back to the caller of the proxy.
                     */
                    abstract contract Proxy {
                        /**
                         * @dev Delegates the current call to `implementation`.
                         *
                         * This function does not return to its internall call site, it will return directly to the external caller.
                         */
                        function _delegate(address implementation) internal virtual {
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                // Copy msg.data. We take full control of memory in this inline assembly
                                // block because it will not return to Solidity code. We overwrite the
                                // Solidity scratch pad at memory position 0.
                                calldatacopy(0, 0, calldatasize())
                                // Call the implementation.
                                // out and outsize are 0 because we don't know the size yet.
                                let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)
                                // Copy the returned data.
                                returndatacopy(0, 0, returndatasize())
                                switch result
                                // delegatecall returns 0 on error.
                                case 0 { revert(0, returndatasize()) }
                                default { return(0, returndatasize()) }
                            }
                        }
                        /**
                         * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
                         * and {_fallback} should delegate.
                         */
                        function _implementation() internal view virtual returns (address);
                        /**
                         * @dev Delegates the current call to the address returned by `_implementation()`.
                         *
                         * This function does not return to its internall call site, it will return directly to the external caller.
                         */
                        function _fallback() internal virtual {
                            _beforeFallback();
                            _delegate(_implementation());
                        }
                        /**
                         * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
                         * function in the contract matches the call data.
                         */
                        fallback () external payable virtual {
                            _fallback();
                        }
                        /**
                         * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
                         * is empty.
                         */
                        receive () external payable virtual {
                            _fallback();
                        }
                        /**
                         * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
                         * call, or as part of the Solidity `fallback` or `receive` functions.
                         *
                         * If overriden should call `super._beforeFallback()`.
                         */
                        function _beforeFallback() internal virtual {
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.2 <0.8.0;
                    /**
                     * @dev Collection of functions related to the address type
                     */
                    library Address {
                        /**
                         * @dev Returns true if `account` is a contract.
                         *
                         * [IMPORTANT]
                         * ====
                         * It is unsafe to assume that an address for which this function returns
                         * false is an externally-owned account (EOA) and not a contract.
                         *
                         * Among others, `isContract` will return false for the following
                         * types of addresses:
                         *
                         *  - an externally-owned account
                         *  - a contract in construction
                         *  - an address where a contract will be created
                         *  - an address where a contract lived, but was destroyed
                         * ====
                         */
                        function isContract(address account) internal view returns (bool) {
                            // This method relies on extcodesize, which returns 0 for contracts in
                            // construction, since the code is only stored at the end of the
                            // constructor execution.
                            uint256 size;
                            // solhint-disable-next-line no-inline-assembly
                            assembly { size := extcodesize(account) }
                            return size > 0;
                        }
                        /**
                         * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
                         * `recipient`, forwarding all available gas and reverting on errors.
                         *
                         * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
                         * of certain opcodes, possibly making contracts go over the 2300 gas limit
                         * imposed by `transfer`, making them unable to receive funds via
                         * `transfer`. {sendValue} removes this limitation.
                         *
                         * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
                         *
                         * IMPORTANT: because control is transferred to `recipient`, care must be
                         * taken to not create reentrancy vulnerabilities. Consider using
                         * {ReentrancyGuard} or the
                         * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
                         */
                        function sendValue(address payable recipient, uint256 amount) internal {
                            require(address(this).balance >= amount, "Address: insufficient balance");
                            // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
                            (bool success, ) = recipient.call{ value: amount }("");
                            require(success, "Address: unable to send value, recipient may have reverted");
                        }
                        /**
                         * @dev Performs a Solidity function call using a low level `call`. A
                         * plain`call` is an unsafe replacement for a function call: use this
                         * function instead.
                         *
                         * If `target` reverts with a revert reason, it is bubbled up by this
                         * function (like regular Solidity function calls).
                         *
                         * Returns the raw returned data. To convert to the expected return value,
                         * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
                         *
                         * Requirements:
                         *
                         * - `target` must be a contract.
                         * - calling `target` with `data` must not revert.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                          return functionCall(target, data, "Address: low-level call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
                         * `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, 0, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but also transferring `value` wei to `target`.
                         *
                         * Requirements:
                         *
                         * - the calling contract must have an ETH balance of at least `value`.
                         * - the called Solidity function must be `payable`.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
                         * with `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
                            require(address(this).balance >= value, "Address: insufficient balance for call");
                            require(isContract(target), "Address: call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.call{ value: value }(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                            return functionStaticCall(target, data, "Address: low-level static call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
                            require(isContract(target), "Address: static call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.staticcall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                            return functionDelegateCall(target, data, "Address: low-level delegate call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            require(isContract(target), "Address: delegate call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.delegatecall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
                            if (success) {
                                return returndata;
                            } else {
                                // Look for revert reason and bubble it up if present
                                if (returndata.length > 0) {
                                    // The easiest way to bubble the revert reason is using memory via assembly
                                    // solhint-disable-next-line no-inline-assembly
                                    assembly {
                                        let returndata_size := mload(returndata)
                                        revert(add(32, returndata), returndata_size)
                                    }
                                } else {
                                    revert(errorMessage);
                                }
                            }
                        }
                    }
                    

                    File 6 of 9: L1GatewayRouter
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "arb-bridge-eth/contracts/libraries/Whitelist.sol";
                    import { ArbitrumEnabledToken } from "../ICustomToken.sol";
                    import "../L1ArbitrumMessenger.sol";
                    import "../../libraries/gateway/GatewayRouter.sol";
                    import "../../arbitrum/gateway/L2GatewayRouter.sol";
                    /**
                     * @title Handles deposits from Erhereum into Arbitrum. Tokens are routered to their appropriate L1 gateway (Router itself also conforms to the Gateway itnerface).
                     * @notice Router also serves as an L1-L2 token address oracle.
                     */
                    contract L1GatewayRouter is WhitelistConsumer, L1ArbitrumMessenger, GatewayRouter {
                        address public owner;
                        address public inbox;
                        modifier onlyOwner() {
                            require(msg.sender == owner, "ONLY_OWNER");
                            _;
                        }
                        function initialize(
                            address _owner,
                            address _defaultGateway,
                            address _whitelist,
                            address _counterpartGateway,
                            address _inbox
                        ) public {
                            GatewayRouter._initialize(_counterpartGateway, address(0), _defaultGateway);
                            owner = _owner;
                            WhitelistConsumer.whitelist = _whitelist;
                            inbox = _inbox;
                        }
                        function setDefaultGateway(
                            address newL1DefaultGateway,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            uint256 _maxSubmissionCost
                        ) external payable onlyOwner returns (uint256) {
                            defaultGateway = newL1DefaultGateway;
                            emit DefaultGatewayUpdated(newL1DefaultGateway);
                            address l2NewDefaultGateway;
                            if (newL1DefaultGateway != address(0)) {
                                l2NewDefaultGateway = TokenGateway(newL1DefaultGateway).counterpartGateway();
                            }
                            bytes memory data = abi.encodeWithSelector(
                                L2GatewayRouter.setDefaultGateway.selector,
                                l2NewDefaultGateway
                            );
                            return
                                sendTxToL2(
                                    inbox,
                                    counterpartGateway,
                                    msg.sender,
                                    msg.value,
                                    0,
                                    L2GasParams({
                                        _maxSubmissionCost: _maxSubmissionCost,
                                        _maxGas: _maxGas,
                                        _gasPriceBid: _gasPriceBid
                                    }),
                                    data
                                );
                        }
                        function setOwner(address newOwner) external onlyOwner {
                            require(newOwner != address(0), "INVALID_OWNER");
                            // set newOwner to address(1) to disable owner and keep `initialize` safe
                            owner = newOwner;
                        }
                        function _setGateways(
                            address[] memory _token,
                            address[] memory _gateway,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            uint256 _maxSubmissionCost,
                            address _creditBackAddress
                        ) internal returns (uint256) {
                            require(_token.length == _gateway.length, "WRONG_LENGTH");
                            for (uint256 i = 0; i < _token.length; i++) {
                                l1TokenToGateway[_token[i]] = _gateway[i];
                                emit GatewaySet(_token[i], _gateway[i]);
                                // overwrite memory so the L2 router receives the L2 address of each gateway
                                if (_gateway[i] != address(0)) {
                                    // if we are assigning a gateway to the token, the address oracle of the gateway
                                    // must return something other than the 0 address
                                    // this check helps avoid misconfiguring gateways
                                    require(
                                        TokenGateway(_gateway[i]).calculateL2TokenAddress(_token[i]) != address(0),
                                        "TOKEN_NOT_HANDLED_BY_GATEWAY"
                                    );
                                    _gateway[i] = TokenGateway(_gateway[i]).counterpartGateway();
                                }
                            }
                            bytes memory data = abi.encodeWithSelector(
                                L2GatewayRouter.setGateway.selector,
                                _token,
                                _gateway
                            );
                            return
                                sendTxToL2(
                                    inbox,
                                    counterpartGateway,
                                    _creditBackAddress,
                                    msg.value,
                                    0,
                                    L2GasParams({
                                        _maxSubmissionCost: _maxSubmissionCost,
                                        _maxGas: _maxGas,
                                        _gasPriceBid: _gasPriceBid
                                    }),
                                    data
                                );
                        }
                        /**
                         * @notice Allows L1 Token contract to trustlessly register its gateway. (other setGateway method allows excess eth recovery from _maxSubmissionCost and is recommended)
                         * @param _gateway l1 gateway address
                         * @param _maxGas max gas for L2 retryable exrecution 
                         * @param _gasPriceBid gas price for L2 retryable ticket 
                         * @param  _maxSubmissionCost base submission cost  L2 retryable tick3et 
                         * @return Retryable ticket ID
                         */
                        function setGateway(
                            address _gateway,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            uint256 _maxSubmissionCost
                        ) external payable returns (uint256) {
                            return setGateway(_gateway, _maxGas, _gasPriceBid, _maxSubmissionCost, msg.sender);
                        }
                        /**
                         * @notice Allows L1 Token contract to trustlessly register its gateway.
                         * param _gateway l1 gateway address
                         * param _maxGas max gas for L2 retryable exrecution
                         * param _gasPriceBid gas price for L2 retryable ticket
                         * param  _maxSubmissionCost base submission cost  L2 retryable tick3et
                         * param _creditBackAddress address for crediting back overpayment of _maxSubmissionCost
                         * return Retryable ticket ID
                         */
                        function setGateway(
                            address, /* _gateway */
                            uint256, /* _maxGas */
                            uint256, /* _gasPriceBid */
                            uint256, /* _maxSubmissionCost */
                            address /* _creditBackAddress */
                        ) public payable returns (uint256) {
                            revert("SELF_REGISTRATION_DISABLED");
                            /*
                            require(
                                ArbitrumEnabledToken(msg.sender).isArbitrumEnabled() == uint8(0xa4b1),
                                "NOT_ARB_ENABLED"
                            );
                            require(_gateway.isContract(), "NOT_TO_CONTRACT");
                            address currGateway = l1TokenToGateway[msg.sender];
                            if (currGateway != address(0)) {
                                // if gateway is already set, don't allow it to set a different gateway
                                require(currGateway == _gateway, "NO_UPDATE_TO_DIFFERENT_ADDR");
                            }
                            address[] memory _tokenArr = new address[](1);
                            _tokenArr[0] = address(msg.sender);
                            address[] memory _gatewayArr = new address[](1);
                            _gatewayArr[0] = _gateway;
                            return
                                _setGateways(
                                    _tokenArr,
                                    _gatewayArr,
                                    _maxGas,
                                    _gasPriceBid,
                                    _maxSubmissionCost,
                                    _creditBackAddress
                                );
                            */
                        }
                        function setGateways(
                            address[] memory _token,
                            address[] memory _gateway,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            uint256 _maxSubmissionCost
                        ) external payable onlyOwner returns (uint256) {
                            // it is assumed that token and gateway are both contracts
                            // require(_token[i].isContract() && _gateway[i].isContract(), "NOT_CONTRACT");
                            return
                                _setGateways(_token, _gateway, _maxGas, _gasPriceBid, _maxSubmissionCost, msg.sender);
                        }
                        function outboundTransfer(
                            address _token,
                            address _to,
                            uint256 _amount,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            bytes calldata _data
                        ) public payable override onlyWhitelisted returns (bytes memory) {
                            // when sending a L1 to L2 transaction, we expect the user to send
                            // eth in flight in order to pay for L2 gas costs
                            // this check prevents users from misconfiguring the msg.value
                            (uint256 _maxSubmissionCost, ) = abi.decode(_data, (uint256, bytes));
                            // here we don't use SafeMath since this validation is to prevent users
                            // from shooting themselves on the foot.
                            uint256 expectedEth = _maxSubmissionCost + (_maxGas * _gasPriceBid);
                            require(_maxSubmissionCost > 0, "NO_SUBMISSION_COST");
                            require(msg.value == expectedEth, "WRONG_ETH_VALUE");
                            // will revert if msg.sender is not whitelisted
                            return super.outboundTransfer(_token, _to, _amount, _maxGas, _gasPriceBid, _data);
                        }
                        modifier onlyCounterpartGateway() override {
                            // don't expect messages from L2 router
                            revert("ONLY_COUNTERPART_GATEWAY");
                            _;
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    abstract contract WhitelistConsumer {
                        address public whitelist;
                        event WhitelistSourceUpdated(address newSource);
                        modifier onlyWhitelisted() {
                            if (whitelist != address(0)) {
                                require(Whitelist(whitelist).isAllowed(msg.sender), "NOT_WHITELISTED");
                            }
                            _;
                        }
                        function updateWhitelistSource(address newSource) external {
                            require(msg.sender == whitelist, "NOT_FROM_LIST");
                            whitelist = newSource;
                            emit WhitelistSourceUpdated(newSource);
                        }
                    }
                    contract Whitelist {
                        address public owner;
                        mapping(address => bool) public isAllowed;
                        event OwnerUpdated(address newOwner);
                        event WhitelistUpgraded(address newWhitelist, address[] targets);
                        constructor() public {
                            owner = msg.sender;
                        }
                        modifier onlyOwner() {
                            require(msg.sender == owner, "ONLY_OWNER");
                            _;
                        }
                        function setOwner(address newOwner) external onlyOwner {
                            owner = newOwner;
                            emit OwnerUpdated(newOwner);
                        }
                        function setWhitelist(address[] memory user, bool[] memory val) external onlyOwner {
                            require(user.length == val.length, "INVALID_INPUT");
                            for (uint256 i = 0; i < user.length; i++) {
                                isAllowed[user[i]] = val[i];
                            }
                        }
                        // set new whitelist to address(0) to disable whitelist
                        function triggerConsumers(address newWhitelist, address[] memory targets) external onlyOwner {
                            for (uint256 i = 0; i < targets.length; i++) {
                                WhitelistConsumer(targets[i]).updateWhitelistSource(newWhitelist);
                            }
                            emit WhitelistUpgraded(newWhitelist, targets);
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface ArbitrumEnabledToken {
                        /// @notice should return `0xa4b1` if token is enabled for arbitrum gateways
                        function isArbitrumEnabled() external view returns (uint8);
                    }
                    /**
                     * @title Minimum expected interface for L1 custom token (see TestCustomTokenL1.sol for an example implementation)
                     */
                    interface ICustomToken is ArbitrumEnabledToken {
                        /**
                         * @notice Should make an external call to EthERC20Bridge.registerCustomL2Token
                         */
                        function registerTokenOnL2(
                            address l2CustomTokenAddress,
                            uint256 maxSubmissionCost,
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            address creditBackAddress
                        ) external;
                        function transferFrom(
                            address sender,
                            address recipient,
                            uint256 amount
                        ) external returns (bool);
                        function balanceOf(address account) external view returns (uint256);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "arb-bridge-eth/contracts/bridge/interfaces/IInbox.sol";
                    import "arb-bridge-eth/contracts/bridge/interfaces/IOutbox.sol";
                    /// @notice L1 utility contract to assist with L1 <=> L2 interactions
                    /// @dev this is an abstract contract instead of library so the functions can be easily overriden when testing
                    abstract contract L1ArbitrumMessenger {
                        event TxToL2(address indexed _from, address indexed _to, uint256 indexed _seqNum, bytes _data);
                        struct L2GasParams {
                            uint256 _maxSubmissionCost;
                            uint256 _maxGas;
                            uint256 _gasPriceBid;
                        }
                        function sendTxToL2(
                            address _inbox,
                            address _to,
                            address _user,
                            uint256 _l1CallValue,
                            uint256 _l2CallValue,
                            L2GasParams memory _l2GasParams,
                            bytes memory _data
                        ) internal virtual returns (uint256) {
                            // alternative function entry point when struggling with the stack size
                            return
                                sendTxToL2(
                                    _inbox,
                                    _to,
                                    _user,
                                    _l1CallValue,
                                    _l2CallValue,
                                    _l2GasParams._maxSubmissionCost,
                                    _l2GasParams._maxGas,
                                    _l2GasParams._gasPriceBid,
                                    _data
                                );
                        }
                        function sendTxToL2(
                            address _inbox,
                            address _to,
                            address _user,
                            uint256 _l1CallValue,
                            uint256 _l2CallValue,
                            uint256 _maxSubmissionCost,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            bytes memory _data
                        ) internal virtual returns (uint256) {
                            uint256 seqNum = IInbox(_inbox).createRetryableTicket{ value: _l1CallValue }(
                                _to,
                                _l2CallValue,
                                _maxSubmissionCost,
                                _user,
                                _user,
                                _maxGas,
                                _gasPriceBid,
                                _data
                            );
                            emit TxToL2(_user, _to, seqNum, _data);
                            return seqNum;
                        }
                        function getBridge(address _inbox) internal view virtual returns (IBridge) {
                            return IInbox(_inbox).bridge();
                        }
                        /// @dev the l2ToL1Sender behaves as the tx.origin, the msg.sender should be validated to protect against reentrancies
                        function getL2ToL1Sender(address _inbox) internal view virtual returns (address) {
                            IOutbox outbox = IOutbox(getBridge(_inbox).activeOutbox());
                            address l2ToL1Sender = outbox.l2ToL1Sender();
                            require(l2ToL1Sender != address(0), "NO_SENDER");
                            return l2ToL1Sender;
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "arb-bridge-eth/contracts/libraries/ProxyUtil.sol";
                    import "@openzeppelin/contracts/utils/Address.sol";
                    import "./TokenGateway.sol";
                    import "./GatewayMessageHandler.sol";
                    /**
                     * @title Common interface for L1 and L2 Gateway Routers
                     */
                    abstract contract GatewayRouter is TokenGateway {
                        using Address for address;
                        address internal constant ZERO_ADDR = address(0);
                        address internal constant DISABLED = address(1);
                        mapping(address => address) public l1TokenToGateway;
                        address public defaultGateway;
                        event TransferRouted(
                            address indexed token,
                            address indexed _userFrom,
                            address indexed _userTo,
                            address gateway
                        );
                        event GatewaySet(address indexed l1Token, address indexed gateway);
                        event DefaultGatewayUpdated(address newDefaultGateway);
                        function postUpgradeInit() external {
                            // it is assumed the L2 Arbitrum Gateway contract is behind a Proxy controlled by a proxy admin
                            // this function can only be called by the proxy admin contract
                            address proxyAdmin = ProxyUtil.getProxyAdmin();
                            require(msg.sender == proxyAdmin, "NOT_FROM_ADMIN");
                            // this has no other logic since the current upgrade doesn't require this logic
                        }
                        function _initialize(
                            address _counterpartGateway,
                            address _router,
                            address _defaultGateway
                        ) internal {
                            // if you are a router, you can't have a router
                            require(_router == address(0), "BAD_ROUTER");
                            TokenGateway._initialize(_counterpartGateway, _router);
                            // default gateway can have 0 address
                            defaultGateway = _defaultGateway;
                        }
                        function finalizeInboundTransfer(
                            address, /* _token */
                            address, /* _from */
                            address, /* _to */
                            uint256, /* _amount */
                            bytes calldata /* _data */
                        ) external payable virtual override {
                            revert("ONLY_OUTBOUND_ROUTER");
                        }
                        function outboundTransfer(
                            address _token,
                            address _to,
                            uint256 _amount,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            bytes calldata _data
                        ) public payable virtual override returns (bytes memory) {
                            address gateway = getGateway(_token);
                            bytes memory gatewayData = GatewayMessageHandler.encodeFromRouterToGateway(
                                msg.sender,
                                _data
                            );
                            emit TransferRouted(_token, msg.sender, _to, gateway);
                            return
                                ITokenGateway(gateway).outboundTransfer{ value: msg.value }(
                                    _token,
                                    _to,
                                    _amount,
                                    _maxGas,
                                    _gasPriceBid,
                                    gatewayData
                                );
                        }
                        function getOutboundCalldata(
                            address _token,
                            address _from,
                            address _to,
                            uint256 _amount,
                            bytes memory _data
                        ) public view virtual override returns (bytes memory) {
                            address gateway = getGateway(_token);
                            return TokenGateway(gateway).getOutboundCalldata(_token, _from, _to, _amount, _data);
                        }
                        function getGateway(address _token) public view virtual returns (address gateway) {
                            gateway = l1TokenToGateway[_token];
                            if (gateway == ZERO_ADDR) {
                                // if no gateway value set, use default gateway
                                gateway = defaultGateway;
                            }
                            if (gateway == DISABLED || !gateway.isContract()) {
                                // not a valid gateway
                                return ZERO_ADDR;
                            }
                            return gateway;
                        }
                        function calculateL2TokenAddress(address l1ERC20)
                            public
                            view
                            virtual
                            override
                            returns (address)
                        {
                            address gateway = getGateway(l1ERC20);
                            if (gateway == ZERO_ADDR) {
                                return ZERO_ADDR;
                            }
                            return TokenGateway(gateway).calculateL2TokenAddress(l1ERC20);
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "../../libraries/gateway/GatewayRouter.sol";
                    import "../../ethereum/gateway/L1GatewayRouter.sol";
                    import "../L2ArbitrumMessenger.sol";
                    import "arb-bridge-eth/contracts/libraries/AddressAliasHelper.sol";
                    /**
                     * @title Handles withdrawals from Ethereum into Arbitrum. Tokens are routered to their appropriate L2 gateway (Router itself also conforms to the Gateway interface).
                     * @notice Router also serves as an L2-L1 token address oracle.
                     */
                    contract L2GatewayRouter is GatewayRouter, L2ArbitrumMessenger {
                        modifier onlyCounterpartGateway() override {
                            require(
                                msg.sender == counterpartGateway ||
                                    AddressAliasHelper.undoL1ToL2Alias(msg.sender) == counterpartGateway,
                                "ONLY_COUNTERPART_GATEWAY"
                            );
                            _;
                        }
                        function initialize(address _counterpartGateway, address _defaultGateway) public {
                            GatewayRouter._initialize(_counterpartGateway, address(0), _defaultGateway);
                        }
                        function setGateway(address[] memory _l1Token, address[] memory _gateway)
                            external
                            onlyCounterpartGateway
                        {
                            // counterpart gateway (L1 router) should never allow wrong lengths
                            assert(_l1Token.length == _gateway.length);
                            for (uint256 i = 0; i < _l1Token.length; i++) {
                                l1TokenToGateway[_l1Token[i]] = _gateway[i];
                                emit GatewaySet(_l1Token[i], _gateway[i]);
                            }
                        }
                        function outboundTransfer(
                            address _l1Token,
                            address _to,
                            uint256 _amount,
                            bytes calldata _data
                        ) public payable returns (bytes memory) {
                            return outboundTransfer(_l1Token, _to, _amount, 0, 0, _data);
                        }
                        function setDefaultGateway(address newL2DefaultGateway) external onlyCounterpartGateway {
                            defaultGateway = newL2DefaultGateway;
                            emit DefaultGatewayUpdated(newL2DefaultGateway);
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "./IBridge.sol";
                    import "./IMessageProvider.sol";
                    interface IInbox is IMessageProvider {
                        function sendL2Message(bytes calldata messageData) external returns (uint256);
                        function sendUnsignedTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            uint256 nonce,
                            address destAddr,
                            uint256 amount,
                            bytes calldata data
                        ) external returns (uint256);
                        function sendContractTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            address destAddr,
                            uint256 amount,
                            bytes calldata data
                        ) external returns (uint256);
                        function sendL1FundedUnsignedTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            uint256 nonce,
                            address destAddr,
                            bytes calldata data
                        ) external payable returns (uint256);
                        function sendL1FundedContractTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            address destAddr,
                            bytes calldata data
                        ) external payable returns (uint256);
                        function createRetryableTicket(
                            address destAddr,
                            uint256 arbTxCallValue,
                            uint256 maxSubmissionCost,
                            address submissionRefundAddress,
                            address valueRefundAddress,
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            bytes calldata data
                        ) external payable returns (uint256);
                        function depositEth(uint256 maxSubmissionCost) external payable returns (uint256);
                        function bridge() external view returns (IBridge);
                        function pauseCreateRetryables() external;
                        function unpauseCreateRetryables() external;
                        function startRewriteAddress() external;
                        function stopRewriteAddress() external;
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface IOutbox {
                        event OutboxEntryCreated(
                            uint256 indexed batchNum,
                            uint256 outboxEntryIndex,
                            bytes32 outputRoot,
                            uint256 numInBatch
                        );
                        event OutBoxTransactionExecuted(
                            address indexed destAddr,
                            address indexed l2Sender,
                            uint256 indexed outboxEntryIndex,
                            uint256 transactionIndex
                        );
                        function l2ToL1Sender() external view returns (address);
                        function l2ToL1Block() external view returns (uint256);
                        function l2ToL1EthBlock() external view returns (uint256);
                        function l2ToL1Timestamp() external view returns (uint256);
                        function l2ToL1BatchNum() external view returns (uint256);
                        function l2ToL1OutputId() external view returns (bytes32);
                        function processOutgoingMessages(bytes calldata sendsData, uint256[] calldata sendLengths)
                            external;
                        function outboxEntryExists(uint256 batchNum) external view returns (bool);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface IBridge {
                        event MessageDelivered(
                            uint256 indexed messageIndex,
                            bytes32 indexed beforeInboxAcc,
                            address inbox,
                            uint8 kind,
                            address sender,
                            bytes32 messageDataHash
                        );
                        event BridgeCallTriggered(
                            address indexed outbox,
                            address indexed destAddr,
                            uint256 amount,
                            bytes data
                        );
                        event InboxToggle(address indexed inbox, bool enabled);
                        event OutboxToggle(address indexed outbox, bool enabled);
                        function deliverMessageToInbox(
                            uint8 kind,
                            address sender,
                            bytes32 messageDataHash
                        ) external payable returns (uint256);
                        function executeCall(
                            address destAddr,
                            uint256 amount,
                            bytes calldata data
                        ) external returns (bool success, bytes memory returnData);
                        // These are only callable by the admin
                        function setInbox(address inbox, bool enabled) external;
                        function setOutbox(address inbox, bool enabled) external;
                        // View functions
                        function activeOutbox() external view returns (address);
                        function allowedInboxes(address inbox) external view returns (bool);
                        function allowedOutboxes(address outbox) external view returns (bool);
                        function inboxAccs(uint256 index) external view returns (bytes32);
                        function messageCount() external view returns (uint256);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface IMessageProvider {
                        event InboxMessageDelivered(uint256 indexed messageNum, bytes data);
                        event InboxMessageDeliveredFromOrigin(uint256 indexed messageNum);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    library ProxyUtil {
                        function getProxyAdmin() internal view returns (address admin) {
                            // https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v3.4.0/contracts/proxy/TransparentUpgradeableProxy.sol#L48
                            // Storage slot with the admin of the proxy contract.
                            // This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
                            bytes32 slot = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
                            assembly {
                                admin := sload(slot)
                            }
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.2 <0.8.0;
                    /**
                     * @dev Collection of functions related to the address type
                     */
                    library Address {
                        /**
                         * @dev Returns true if `account` is a contract.
                         *
                         * [IMPORTANT]
                         * ====
                         * It is unsafe to assume that an address for which this function returns
                         * false is an externally-owned account (EOA) and not a contract.
                         *
                         * Among others, `isContract` will return false for the following
                         * types of addresses:
                         *
                         *  - an externally-owned account
                         *  - a contract in construction
                         *  - an address where a contract will be created
                         *  - an address where a contract lived, but was destroyed
                         * ====
                         */
                        function isContract(address account) internal view returns (bool) {
                            // This method relies on extcodesize, which returns 0 for contracts in
                            // construction, since the code is only stored at the end of the
                            // constructor execution.
                            uint256 size;
                            // solhint-disable-next-line no-inline-assembly
                            assembly { size := extcodesize(account) }
                            return size > 0;
                        }
                        /**
                         * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
                         * `recipient`, forwarding all available gas and reverting on errors.
                         *
                         * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
                         * of certain opcodes, possibly making contracts go over the 2300 gas limit
                         * imposed by `transfer`, making them unable to receive funds via
                         * `transfer`. {sendValue} removes this limitation.
                         *
                         * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
                         *
                         * IMPORTANT: because control is transferred to `recipient`, care must be
                         * taken to not create reentrancy vulnerabilities. Consider using
                         * {ReentrancyGuard} or the
                         * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
                         */
                        function sendValue(address payable recipient, uint256 amount) internal {
                            require(address(this).balance >= amount, "Address: insufficient balance");
                            // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
                            (bool success, ) = recipient.call{ value: amount }("");
                            require(success, "Address: unable to send value, recipient may have reverted");
                        }
                        /**
                         * @dev Performs a Solidity function call using a low level `call`. A
                         * plain`call` is an unsafe replacement for a function call: use this
                         * function instead.
                         *
                         * If `target` reverts with a revert reason, it is bubbled up by this
                         * function (like regular Solidity function calls).
                         *
                         * Returns the raw returned data. To convert to the expected return value,
                         * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
                         *
                         * Requirements:
                         *
                         * - `target` must be a contract.
                         * - calling `target` with `data` must not revert.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                          return functionCall(target, data, "Address: low-level call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
                         * `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, 0, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but also transferring `value` wei to `target`.
                         *
                         * Requirements:
                         *
                         * - the calling contract must have an ETH balance of at least `value`.
                         * - the called Solidity function must be `payable`.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
                         * with `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
                            require(address(this).balance >= value, "Address: insufficient balance for call");
                            require(isContract(target), "Address: call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.call{ value: value }(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                            return functionStaticCall(target, data, "Address: low-level static call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
                            require(isContract(target), "Address: static call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.staticcall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                            return functionDelegateCall(target, data, "Address: low-level delegate call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            require(isContract(target), "Address: delegate call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.delegatecall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
                            if (success) {
                                return returndata;
                            } else {
                                // Look for revert reason and bubble it up if present
                                if (returndata.length > 0) {
                                    // The easiest way to bubble the revert reason is using memory via assembly
                                    // solhint-disable-next-line no-inline-assembly
                                    assembly {
                                        let returndata_size := mload(returndata)
                                        revert(add(32, returndata), returndata_size)
                                    }
                                } else {
                                    revert(errorMessage);
                                }
                            }
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "./ITokenGateway.sol";
                    import "@openzeppelin/contracts/utils/Address.sol";
                    abstract contract TokenGateway is ITokenGateway {
                        using Address for address;
                        address public counterpartGateway;
                        address public router;
                        modifier onlyCounterpartGateway() virtual {
                            // this method is overriden in gateways that require special logic for validation
                            // ie L2 to L1 messages need to be validated against the outbox
                            require(msg.sender == counterpartGateway, "ONLY_COUNTERPART_GATEWAY");
                            _;
                        }
                        function _initialize(address _counterpartGateway, address _router) internal virtual {
                            // This initializes internal variables of the abstract contract it can be chained together with other functions.
                            // It is virtual so subclasses can override or wrap around this logic.
                            // An example where this is useful is different subclasses that validate the router address differently
                            require(_counterpartGateway != address(0), "INVALID_COUNTERPART");
                            require(counterpartGateway == address(0), "ALREADY_INIT");
                            counterpartGateway = _counterpartGateway;
                            router = _router;
                        }
                        function isRouter(address _target) internal view returns (bool isTargetRouter) {
                            return _target == router;
                        }
                        /**
                         * @notice Calculate the address used when bridging an ERC20 token
                         * @dev the L1 and L2 address oracles may not always be in sync.
                         * For example, a custom token may have been registered but not deploy or the contract self destructed.
                         * @param l1ERC20 address of L1 token
                         * @return L2 address of a bridged ERC20 token
                         */
                        function calculateL2TokenAddress(address l1ERC20)
                            public
                            view
                            virtual
                            override
                            returns (address);
                        function outboundTransfer(
                            address _token,
                            address _to,
                            uint256 _amount,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            bytes calldata _data
                        ) external payable virtual override returns (bytes memory);
                        function getOutboundCalldata(
                            address _token,
                            address _from,
                            address _to,
                            uint256 _amount,
                            bytes memory _data
                        ) public view virtual returns (bytes memory);
                        function finalizeInboundTransfer(
                            address _token,
                            address _from,
                            address _to,
                            uint256 _amount,
                            bytes calldata _data
                        ) external payable virtual override;
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    /// @notice this library manages encoding and decoding of gateway communication
                    library GatewayMessageHandler {
                        // these are for communication from L1 to L2 gateway
                        function encodeToL2GatewayMsg(bytes memory gatewayData, bytes memory callHookData)
                            internal
                            pure
                            returns (bytes memory res)
                        {
                            res = abi.encode(gatewayData, callHookData);
                        }
                        function parseFromL1GatewayMsg(bytes calldata _data)
                            internal
                            pure
                            returns (bytes memory gatewayData, bytes memory callHookData)
                        {
                            // abi decode may revert, but the encoding is done by L1 gateway, so we trust it
                            (gatewayData, callHookData) = abi.decode(_data, (bytes, bytes));
                        }
                        // these are for communication from L2 to L1 gateway
                        function encodeFromL2GatewayMsg(uint256 exitNum, bytes memory callHookData)
                            internal
                            pure
                            returns (bytes memory res)
                        {
                            res = abi.encode(exitNum, callHookData);
                        }
                        function parseToL1GatewayMsg(bytes calldata _data)
                            internal
                            pure
                            returns (uint256 exitNum, bytes memory callHookData)
                        {
                            // abi decode may revert, but the encoding is done by L1 gateway, so we trust it
                            (exitNum, callHookData) = abi.decode(_data, (uint256, bytes));
                        }
                        // these are for communication from router to gateway
                        function encodeFromRouterToGateway(address _from, bytes calldata _data)
                            internal
                            pure
                            returns (bytes memory res)
                        {
                            // abi decode may revert, but the encoding is done by L1 gateway, so we trust it
                            return abi.encode(_from, _data);
                        }
                        function parseFromRouterToGateway(bytes calldata _data)
                            internal
                            pure
                            returns (address, bytes memory res)
                        {
                            // abi decode may revert, but the encoding is done by L1 gateway, so we trust it
                            return abi.decode(_data, (address, bytes));
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface ITokenGateway {
                        /// @notice event deprecated in favor of DepositInitiated and WithdrawalInitiated
                        // event OutboundTransferInitiated(
                        //     address token,
                        //     address indexed _from,
                        //     address indexed _to,
                        //     uint256 indexed _transferId,
                        //     uint256 _amount,
                        //     bytes _data
                        // );
                        /// @notice event deprecated in favor of DepositFinalized and WithdrawalFinalized
                        // event InboundTransferFinalized(
                        //     address token,
                        //     address indexed _from,
                        //     address indexed _to,
                        //     uint256 indexed _transferId,
                        //     uint256 _amount,
                        //     bytes _data
                        // );
                        function outboundTransfer(
                            address _token,
                            address _to,
                            uint256 _amount,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            bytes calldata _data
                        ) external payable returns (bytes memory);
                        function finalizeInboundTransfer(
                            address _token,
                            address _from,
                            address _to,
                            uint256 _amount,
                            bytes calldata _data
                        ) external payable;
                        /**
                         * @notice Calculate the address used when bridging an ERC20 token
                         * @dev the L1 and L2 address oracles may not always be in sync.
                         * For example, a custom token may have been registered but not deploy or the contract self destructed.
                         * @param l1ERC20 address of L1 token
                         * @return L2 address of a bridged ERC20 token
                         */
                        function calculateL2TokenAddress(address l1ERC20) external view returns (address);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "arbos-contracts/arbos/builtin/ArbSys.sol";
                    /// @notice L2 utility contract to assist with L1 <=> L2 interactions
                    /// @dev this is an abstract contract instead of library so the functions can be easily overriden when testing
                    abstract contract L2ArbitrumMessenger {
                        address internal constant ARB_SYS_ADDRESS = address(100);
                        event TxToL1(address indexed _from, address indexed _to, uint256 indexed _id, bytes _data);
                        function sendTxToL1(
                            uint256 _l1CallValue,
                            address _from,
                            address _to,
                            bytes memory _data
                        ) internal virtual returns (uint256) {
                            uint256 _id = ArbSys(ARB_SYS_ADDRESS).sendTxToL1{ value: _l1CallValue }(_to, _data);
                            emit TxToL1(_from, _to, _id, _data);
                            return _id;
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2019-2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    library AddressAliasHelper {
                        uint160 constant offset = uint160(0x1111000000000000000000000000000000001111);
                        /// @notice Utility function that converts the address in the L1 that submitted a tx to
                        /// the inbox to the msg.sender viewed in the L2
                        /// @param l1Address the address in the L1 that triggered the tx to L2
                        /// @return l2Address L2 address as viewed in msg.sender
                        function applyL1ToL2Alias(address l1Address) internal pure returns (address l2Address) {
                            l2Address = address(uint160(l1Address) + offset);
                        }
                        /// @notice Utility function that converts the msg.sender viewed in the L2 to the
                        /// address in the L1 that submitted a tx to the inbox
                        /// @param l2Address L2 address as viewed in msg.sender
                        /// @return l1Address the address in the L1 that triggered the tx to L2
                        function undoL1ToL2Alias(address l2Address) internal pure returns (address l1Address) {
                            l1Address = address(uint160(l2Address) - offset);
                        }
                    }
                    pragma solidity >=0.4.21 <0.7.0;
                    /**
                    * @title Precompiled contract that exists in every Arbitrum chain at address(100), 0x0000000000000000000000000000000000000064. Exposes a variety of system-level functionality.
                     */
                    interface ArbSys {
                        /**
                        * @notice Get internal version number identifying an ArbOS build
                        * @return version number as int
                         */
                        function arbOSVersion() external pure returns (uint);
                        function arbChainID() external view returns(uint);
                        /**
                        * @notice Get Arbitrum block number (distinct from L1 block number; Arbitrum genesis block has block number 0)
                        * @return block number as int
                         */ 
                        function arbBlockNumber() external view returns (uint);
                        /** 
                        * @notice Send given amount of Eth to dest from sender.
                        * This is a convenience function, which is equivalent to calling sendTxToL1 with empty calldataForL1.
                        * @param destination recipient address on L1
                        * @return unique identifier for this L2-to-L1 transaction.
                        */
                        function withdrawEth(address destination) external payable returns(uint);
                        /** 
                        * @notice Send a transaction to L1
                        * @param destination recipient address on L1 
                        * @param calldataForL1 (optional) calldata for L1 contract call
                        * @return a unique identifier for this L2-to-L1 transaction.
                        */
                        function sendTxToL1(address destination, bytes calldata calldataForL1) external payable returns(uint);
                        /** 
                        * @notice get the number of transactions issued by the given external account or the account sequence number of the given contract
                        * @param account target account
                        * @return the number of transactions issued by the given external account or the account sequence number of the given contract
                        */
                        function getTransactionCount(address account) external view returns(uint256);
                        /**  
                        * @notice get the value of target L2 storage slot 
                        * This function is only callable from address 0 to prevent contracts from being able to call it
                        * @param account target account
                        * @param index target index of storage slot 
                        * @return stotage value for the given account at the given index
                        */
                        function getStorageAt(address account, uint256 index) external view returns (uint256);
                        /**
                        * @notice check if current call is coming from l1
                        * @return true if the caller of this was called directly from L1
                        */
                        function isTopLevelCall() external view returns (bool);
                        /**
                         * @notice check if the caller (of this caller of this) is an aliased L1 contract address
                         * @return true iff the caller's address is an alias for an L1 contract address
                         */
                        function wasMyCallersAddressAliased() external view returns (bool);
                        /**
                         * @notice return the address of the caller (of this caller of this), without applying L1 contract address aliasing
                         * @return address of the caller's caller, without applying L1 contract address aliasing
                         */
                        function myCallersAddressWithoutAliasing() external view returns (address);
                        /**
                         * @notice map L1 sender contract address to its L2 alias
                         * @param sender sender address
                         * @param dest destination address
                         * @return aliased sender address
                         */
                        function mapL1SenderContractAddressToL2Alias(address sender, address dest) external pure returns(address);
                        /**
                         * @notice get the caller's amount of available storage gas
                         * @return amount of storage gas available to the caller
                         */
                        function getStorageGasAvailable() external returns(uint);
                        event L2ToL1Transaction(address caller, address indexed destination, uint indexed uniqueId,
                                                uint indexed batchNumber, uint indexInBatch,
                                                uint arbBlockNum, uint ethBlockNum, uint timestamp,
                                                uint callvalue, bytes data);
                    }
                    

                    File 7 of 9: L1CustomGateway
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import { ArbitrumEnabledToken } from "../ICustomToken.sol";
                    import "./L1ArbitrumExtendedGateway.sol";
                    import "../../arbitrum/gateway/L2CustomGateway.sol";
                    import "../../libraries/gateway/ICustomGateway.sol";
                    import "@openzeppelin/contracts/utils/Address.sol";
                    import "arb-bridge-eth/contracts/libraries/Whitelist.sol";
                    /**
                     * @title Gatway for "custom" bridging functionality
                     * @notice Handles some (but not all!) custom Gateway needs.
                     */
                    contract L1CustomGateway is L1ArbitrumExtendedGateway, ICustomGateway {
                        using Address for address;
                        // stores addresses of L2 tokens to be used
                        mapping(address => address) public override l1ToL2Token;
                        // owner is able to force add custom mappings
                        address public owner;
                        // whitelist not used anymore
                        address public whitelist;
                        function initialize(
                            address _l1Counterpart,
                            address _l1Router,
                            address _inbox,
                            address _owner
                        ) public {
                            L1ArbitrumExtendedGateway._initialize(_l1Counterpart, _l1Router, _inbox);
                            owner = _owner;
                            // disable whitelist by default
                            whitelist = address(0);
                        }
                        /**
                         * @notice Calculate the address used when bridging an ERC20 token
                         * @dev the L1 and L2 address oracles may not always be in sync.
                         * For example, a custom token may have been registered but not deploy or the contract self destructed.
                         * @param l1ERC20 address of L1 token
                         * @return L2 address of a bridged ERC20 token
                         */
                        function calculateL2TokenAddress(address l1ERC20) public view override returns (address) {
                            return l1ToL2Token[l1ERC20];
                        }
                        /**
                         * @notice Allows L1 Token contract to trustlessly register its custom L2 counterpart. (other registerTokenToL2 method allows excess eth recovery from _maxSubmissionCost and is recommended)
                         * @param _l2Address counterpart address of L1 token
                         * @param _maxGas max gas for L2 retryable exrecution
                         * @param _gasPriceBid gas price for L2 retryable ticket
                         * @param  _maxSubmissionCost base submission cost  L2 retryable tick3et
                         * @return Retryable ticket ID
                         */
                        function registerTokenToL2(
                            address _l2Address,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            uint256 _maxSubmissionCost
                        ) external payable returns (uint256) {
                            return registerTokenToL2(_l2Address, _maxGas, _gasPriceBid, _maxSubmissionCost, msg.sender);
                        }
                        /**
                         * @notice Allows L1 Token contract to trustlessly register its custom L2 counterpart.
                         * param _l2Address counterpart address of L1 token
                         * param _maxGas max gas for L2 retryable exrecution
                         * param _gasPriceBid gas price for L2 retryable ticket
                         * param  _maxSubmissionCost base submission cost  L2 retryable tick3et
                         * param _creditBackAddress address for crediting back overpayment of _maxSubmissionCost
                         * return Retryable ticket ID
                         */
                        function registerTokenToL2(
                            address, /* _l2Address */
                            uint256, /* _maxGas */
                            uint256, /* _gasPriceBid */
                            uint256, /* _maxSubmissionCost */
                            address /* _creditBackAddress */
                        ) public payable returns (uint256) {
                            revert("SELF_REGISTRATION_DISABLED");
                            /*
                            require(
                                ArbitrumEnabledToken(msg.sender).isArbitrumEnabled() == uint8(0xa4b1),
                                "NOT_ARB_ENABLED"
                            );
                            address currL2Addr = l1ToL2Token[msg.sender];
                            if (currL2Addr != address(0)) {
                                // if token is already set, don't allow it to set a different L2 address
                                require(currL2Addr == _l2Address, "NO_UPDATE_TO_DIFFERENT_ADDR");
                            }
                            l1ToL2Token[msg.sender] = _l2Address;
                            address[] memory l1Addresses = new address[](1);
                            address[] memory l2Addresses = new address[](1);
                            l1Addresses[0] = msg.sender;
                            l2Addresses[0] = _l2Address;
                            emit TokenSet(l1Addresses[0], l2Addresses[0]);
                            bytes memory _data =
                                abi.encodeWithSelector(
                                    L2CustomGateway.registerTokenFromL1.selector,
                                    l1Addresses,
                                    l2Addresses
                                );
                            return
                                sendTxToL2(
                                    inbox,
                                    counterpartGateway,
                                    _creditBackAddress,
                                    msg.value,
                                    0,
                                    _maxSubmissionCost,
                                    _maxGas,
                                    _gasPriceBid,
                                    _data
                                );
                            */
                        }
                        /**
                         * @notice Allows owner to force register a custom L1/L2 token pair.
                         * @dev _l1Addresses[i] counterpart is assumed to be _l2Addresses[i]
                         * @param _l1Addresses array of L1 addresses
                         * @param _l2Addresses array of L2 addresses
                         * @param _maxGas max gas for L2 retryable exrecution
                         * @param _gasPriceBid gas price for L2 retryable ticket
                         * @param  _maxSubmissionCost base submission cost  L2 retryable tick3et
                         * @return Retryable ticket ID
                         */
                        function forceRegisterTokenToL2(
                            address[] calldata _l1Addresses,
                            address[] calldata _l2Addresses,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            uint256 _maxSubmissionCost
                        ) external payable returns (uint256) {
                            require(msg.sender == owner, "ONLY_OWNER");
                            require(_l1Addresses.length == _l2Addresses.length, "INVALID_LENGTHS");
                            for (uint256 i = 0; i < _l1Addresses.length; i++) {
                                // here we assume the owner checked both addresses offchain before force registering
                                // require(address(_l1Addresses[i]).isContract(), "MUST_BE_CONTRACT");
                                l1ToL2Token[_l1Addresses[i]] = _l2Addresses[i];
                                emit TokenSet(_l1Addresses[i], _l2Addresses[i]);
                            }
                            bytes memory _data = abi.encodeWithSelector(
                                L2CustomGateway.registerTokenFromL1.selector,
                                _l1Addresses,
                                _l2Addresses
                            );
                            return
                                sendTxToL2(
                                    inbox,
                                    counterpartGateway,
                                    msg.sender,
                                    msg.value,
                                    0,
                                    _maxSubmissionCost,
                                    _maxGas,
                                    _gasPriceBid,
                                    _data
                                );
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface ArbitrumEnabledToken {
                        /// @notice should return `0xa4b1` if token is enabled for arbitrum gateways
                        function isArbitrumEnabled() external view returns (uint8);
                    }
                    /**
                     * @title Minimum expected interface for L1 custom token (see TestCustomTokenL1.sol for an example implementation)
                     */
                    interface ICustomToken is ArbitrumEnabledToken {
                        /**
                         * @notice Should make an external call to EthERC20Bridge.registerCustomL2Token
                         */
                        function registerTokenOnL2(
                            address l2CustomTokenAddress,
                            uint256 maxSubmissionCost,
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            address creditBackAddress
                        ) external;
                        function transferFrom(
                            address sender,
                            address recipient,
                            uint256 amount
                        ) external returns (bool);
                        function balanceOf(address account) external view returns (uint256);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "../../libraries/ITransferAndCall.sol";
                    import "./L1ArbitrumGateway.sol";
                    interface ITradeableExitReceiver {
                        function onExitTransfer(
                            address sender,
                            uint256 exitNum,
                            bytes calldata data
                        ) external returns (bool);
                    }
                    abstract contract L1ArbitrumExtendedGateway is L1ArbitrumGateway {
                        struct ExitData {
                            bool isExit;
                            address _newTo;
                            bytes _newData;
                        }
                        mapping(bytes32 => ExitData) public redirectedExits;
                        function _initialize(
                            address _l2Counterpart,
                            address _router,
                            address _inbox
                        ) internal virtual override {
                            L1ArbitrumGateway._initialize(_l2Counterpart, _router, _inbox);
                        }
                        event WithdrawRedirected(
                            address indexed from,
                            address indexed to,
                            uint256 indexed exitNum,
                            bytes newData,
                            bytes data,
                            bool madeExternalCall
                        );
                        /**
                         * @notice Allows a user to redirect their right to claim a withdrawal to another address.
                         * @dev This method also allows you to make an arbitrary call after the transfer.
                         * This does not validate if the exit was already triggered. It is assumed the `_exitNum` is
                         * validated off-chain to ensure this was not yet triggered.
                         * @param _exitNum Sequentially increasing exit counter determined by the L2 bridge
                         * @param _initialDestination address the L2 withdrawal call initially set as the destination.
                         * @param _newDestination address the L1 will now call instead of the previously set destination
                         * @param _newData data to be used in inboundEscrowAndCall
                         * @param _data optional data for external call upon transfering the exit
                         */
                        function transferExitAndCall(
                            uint256 _exitNum,
                            address _initialDestination,
                            address _newDestination,
                            bytes calldata _newData,
                            bytes calldata _data
                        ) external {
                            // the initial data doesn't make a difference when transfering you exit
                            // since the L2 bridge gives a unique exit ID to each exit
                            (address expectedSender, ) = getExternalCall(_exitNum, _initialDestination, "");
                            // if you want to transfer your exit, you must be the current destination
                            require(msg.sender == expectedSender, "NOT_EXPECTED_SENDER");
                            // the inboundEscrowAndCall functionality has been disabled, so no data is allowed
                            require(_newData.length == 0, "NO_DATA_ALLOWED");
                            setRedirectedExit(_exitNum, _initialDestination, _newDestination, _newData);
                            if (_data.length > 0) {
                                require(_newDestination.isContract(), "TO_NOT_CONTRACT");
                                bool success =
                                    ITradeableExitReceiver(_newDestination).onExitTransfer(
                                        expectedSender,
                                        _exitNum,
                                        _data
                                    );
                                require(success, "TRANSFER_HOOK_FAIL");
                            }
                            emit WithdrawRedirected(
                                expectedSender,
                                _newDestination,
                                _exitNum,
                                _newData,
                                _data,
                                _data.length > 0
                            );
                        }
                        /// @notice this does not verify if the external call was already done
                        function getExternalCall(
                            uint256 _exitNum,
                            address _initialDestination,
                            bytes memory _initialData
                        ) public view virtual override returns (address target, bytes memory data) {
                            // this function is virtual so that subclasses can override it with custom logic where necessary
                            bytes32 withdrawData = encodeWithdrawal(_exitNum, _initialDestination);
                            ExitData storage exit = redirectedExits[withdrawData];
                            // here we don't authenticate `_initialData`. we could hash it into `withdrawData` but would increase gas costs
                            // this is safe because if the exit isn't overriden, the _initialData coming from L2 is trusted
                            // but if the exit is traded, all we care about is the latest user calldata
                            if (exit.isExit) {
                                return (exit._newTo, exit._newData);
                            } else {
                                return (_initialDestination, _initialData);
                            }
                        }
                        function setRedirectedExit(
                            uint256 _exitNum,
                            address _initialDestination,
                            address _newDestination,
                            bytes memory _newData
                        ) internal {
                            bytes32 withdrawData = encodeWithdrawal(_exitNum, _initialDestination);
                            redirectedExits[withdrawData] = ExitData(true, _newDestination, _newData);
                        }
                        function encodeWithdrawal(uint256 _exitNum, address _initialDestination)
                            public
                            pure
                            returns (bytes32)
                        {
                            // here we assume the L2 bridge gives a unique exitNum to each exit
                            return keccak256(abi.encode(_exitNum, _initialDestination));
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "./L2ArbitrumGateway.sol";
                    import "../../libraries/gateway/ICustomGateway.sol";
                    import "@openzeppelin/contracts/math/SafeMath.sol";
                    import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
                    contract L2CustomGateway is L2ArbitrumGateway, ICustomGateway {
                        // stores addresses of L2 tokens to be used
                        mapping(address => address) public override l1ToL2Token;
                        function initialize(address _l1Counterpart, address _router) public {
                            L2ArbitrumGateway._initialize(_l1Counterpart, _router);
                        }
                        /**
                         * @notice internal utility function used to handle when no contract is deployed at expected address
                         */
                        function handleNoContract(
                            address _l1Token,
                            address, /* expectedL2Address */
                            address _from,
                            address, /* _to */
                            uint256 _amount,
                            bytes memory /* gatewayData */
                        ) internal override returns (bool shouldHalt) {
                            // it is assumed that the custom token is deployed in the L2 before deposits are made
                            // trigger withdrawal
                            // we don't need the return value from triggerWithdrawal since this is forcing a withdrawal back to the L1
                            // instead of composing with a L2 dapp
                            triggerWithdrawal(_l1Token, address(this), _from, _amount, "");
                            return true;
                        }
                        function outboundEscrowTransfer(
                            address _l2Token,
                            address _from,
                            uint256 _amount
                        ) internal override returns (uint256 amountBurnt) {
                            uint256 prevBalance = IERC20(_l2Token).balanceOf(_from);
                            // in the custom gateway, we do the same behaviour as the superclass, but actually check
                            // for the balances of tokens to ensure that inflationary / deflationary changes in the amount
                            // are taken into account
                            // we ignore the return value since we actually query the token before and after to calculate
                            // the amount of tokens that were burnt
                            super.outboundEscrowTransfer(_l2Token, _from, _amount);
                            uint256 postBalance = IERC20(_l2Token).balanceOf(_from);
                            return SafeMath.sub(prevBalance, postBalance);
                        }
                        /**
                         * @notice Calculate the address used when bridging an ERC20 token
                         * @dev the L1 and L2 address oracles may not always be in sync.
                         * For example, a custom token may have been registered but not deploy or the contract self destructed.
                         * @param l1ERC20 address of L1 token
                         * @return L2 address of a bridged ERC20 token
                         */
                        function calculateL2TokenAddress(address l1ERC20) public view override returns (address) {
                            return l1ToL2Token[l1ERC20];
                        }
                        function registerTokenFromL1(address[] calldata l1Address, address[] calldata l2Address)
                            external
                            onlyCounterpartGateway
                        {
                            // we assume both arrays are the same length, safe since its encoded by the L1
                            for (uint256 i = 0; i < l1Address.length; i++) {
                                // here we don't check if l2Address is a contract and instead deal with that behaviour
                                // in `handleNoContract` this way we keep the l1 and l2 address oracles in sync
                                l1ToL2Token[l1Address[i]] = l2Address[i];
                                emit TokenSet(l1Address[i], l2Address[i]);
                            }
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    // import "./ITokenGateway.sol";
                    interface ICustomGateway {
                        function l1ToL2Token(address _l1Token) external view returns (address _l2Token);
                        event TokenSet(address indexed l1Address, address indexed l2Address);
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.2 <0.8.0;
                    /**
                     * @dev Collection of functions related to the address type
                     */
                    library Address {
                        /**
                         * @dev Returns true if `account` is a contract.
                         *
                         * [IMPORTANT]
                         * ====
                         * It is unsafe to assume that an address for which this function returns
                         * false is an externally-owned account (EOA) and not a contract.
                         *
                         * Among others, `isContract` will return false for the following
                         * types of addresses:
                         *
                         *  - an externally-owned account
                         *  - a contract in construction
                         *  - an address where a contract will be created
                         *  - an address where a contract lived, but was destroyed
                         * ====
                         */
                        function isContract(address account) internal view returns (bool) {
                            // This method relies on extcodesize, which returns 0 for contracts in
                            // construction, since the code is only stored at the end of the
                            // constructor execution.
                            uint256 size;
                            // solhint-disable-next-line no-inline-assembly
                            assembly { size := extcodesize(account) }
                            return size > 0;
                        }
                        /**
                         * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
                         * `recipient`, forwarding all available gas and reverting on errors.
                         *
                         * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
                         * of certain opcodes, possibly making contracts go over the 2300 gas limit
                         * imposed by `transfer`, making them unable to receive funds via
                         * `transfer`. {sendValue} removes this limitation.
                         *
                         * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
                         *
                         * IMPORTANT: because control is transferred to `recipient`, care must be
                         * taken to not create reentrancy vulnerabilities. Consider using
                         * {ReentrancyGuard} or the
                         * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
                         */
                        function sendValue(address payable recipient, uint256 amount) internal {
                            require(address(this).balance >= amount, "Address: insufficient balance");
                            // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
                            (bool success, ) = recipient.call{ value: amount }("");
                            require(success, "Address: unable to send value, recipient may have reverted");
                        }
                        /**
                         * @dev Performs a Solidity function call using a low level `call`. A
                         * plain`call` is an unsafe replacement for a function call: use this
                         * function instead.
                         *
                         * If `target` reverts with a revert reason, it is bubbled up by this
                         * function (like regular Solidity function calls).
                         *
                         * Returns the raw returned data. To convert to the expected return value,
                         * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
                         *
                         * Requirements:
                         *
                         * - `target` must be a contract.
                         * - calling `target` with `data` must not revert.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                          return functionCall(target, data, "Address: low-level call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
                         * `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, 0, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but also transferring `value` wei to `target`.
                         *
                         * Requirements:
                         *
                         * - the calling contract must have an ETH balance of at least `value`.
                         * - the called Solidity function must be `payable`.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
                         * with `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
                            require(address(this).balance >= value, "Address: insufficient balance for call");
                            require(isContract(target), "Address: call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.call{ value: value }(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                            return functionStaticCall(target, data, "Address: low-level static call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
                            require(isContract(target), "Address: static call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.staticcall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                            return functionDelegateCall(target, data, "Address: low-level delegate call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            require(isContract(target), "Address: delegate call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.delegatecall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
                            if (success) {
                                return returndata;
                            } else {
                                // Look for revert reason and bubble it up if present
                                if (returndata.length > 0) {
                                    // The easiest way to bubble the revert reason is using memory via assembly
                                    // solhint-disable-next-line no-inline-assembly
                                    assembly {
                                        let returndata_size := mload(returndata)
                                        revert(add(32, returndata), returndata_size)
                                    }
                                } else {
                                    revert(errorMessage);
                                }
                            }
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    abstract contract WhitelistConsumer {
                        address public whitelist;
                        event WhitelistSourceUpdated(address newSource);
                        modifier onlyWhitelisted {
                            if (whitelist != address(0)) {
                                require(Whitelist(whitelist).isAllowed(msg.sender), "NOT_WHITELISTED");
                            }
                            _;
                        }
                        function updateWhitelistSource(address newSource) external {
                            require(msg.sender == whitelist, "NOT_FROM_LIST");
                            whitelist = newSource;
                            emit WhitelistSourceUpdated(newSource);
                        }
                    }
                    contract Whitelist {
                        address public owner;
                        mapping(address => bool) public isAllowed;
                        event OwnerUpdated(address newOwner);
                        event WhitelistUpgraded(address newWhitelist, address[] targets);
                        constructor() public {
                            owner = msg.sender;
                        }
                        modifier onlyOwner {
                            require(msg.sender == owner, "ONLY_OWNER");
                            _;
                        }
                        function setOwner(address newOwner) external onlyOwner {
                            owner = newOwner;
                            emit OwnerUpdated(newOwner);
                        }
                        function setWhitelist(address[] memory user, bool[] memory val) external onlyOwner {
                            require(user.length == val.length, "INVALID_INPUT");
                            for (uint256 i = 0; i < user.length; i++) {
                                isAllowed[user[i]] = val[i];
                            }
                        }
                        // set new whitelist to address(0) to disable whitelist
                        function triggerConsumers(address newWhitelist, address[] memory targets) external onlyOwner {
                            for (uint256 i = 0; i < targets.length; i++) {
                                WhitelistConsumer(targets[i]).updateWhitelistSource(newWhitelist);
                            }
                            emit WhitelistUpgraded(newWhitelist, targets);
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >0.6.0 <0.8.0;
                    import "@openzeppelin/contracts-upgradeable/token/ERC20/IERC20Upgradeable.sol";
                    interface ITransferAndCall is IERC20Upgradeable {
                        function transferAndCall(
                            address to,
                            uint256 value,
                            bytes memory data
                        ) external returns (bool success);
                        event Transfer(address indexed from, address indexed to, uint256 value, bytes data);
                    }
                    /**
                     * @notice note that implementation of ITransferAndCallReceiver is not expected to return a success bool
                     */
                    interface ITransferAndCallReceiver {
                        function onTokenTransfer(
                            address _sender,
                            uint256 _value,
                            bytes memory _data
                        ) external;
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
                    import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
                    import "@openzeppelin/contracts/utils/Create2.sol";
                    import "@openzeppelin/contracts/utils/Address.sol";
                    import "@openzeppelin/contracts/math/SafeMath.sol";
                    import "arb-bridge-eth/contracts/bridge/interfaces/IInbox.sol";
                    import "arb-bridge-eth/contracts/libraries/ProxyUtil.sol";
                    import "../L1ArbitrumMessenger.sol";
                    import "../../libraries/gateway/GatewayMessageHandler.sol";
                    import "../../libraries/gateway/TokenGateway.sol";
                    import "../../libraries/ITransferAndCall.sol";
                    /**
                     * @title Common interface for gatways on L1 messaging to Arbitrum.
                     */
                    abstract contract L1ArbitrumGateway is L1ArbitrumMessenger, TokenGateway {
                        using SafeERC20 for IERC20;
                        using Address for address;
                        address public inbox;
                        event DepositInitiated(
                            address l1Token,
                            address indexed _from,
                            address indexed _to,
                            uint256 indexed _sequenceNumber,
                            uint256 _amount
                        );
                        event WithdrawalFinalized(
                            address l1Token,
                            address indexed _from,
                            address indexed _to,
                            uint256 indexed _exitNum,
                            uint256 _amount
                        );
                        modifier onlyCounterpartGateway() override {
                            address _inbox = inbox;
                            // a message coming from the counterpart gateway was executed by the bridge
                            address bridge = address(super.getBridge(_inbox));
                            require(msg.sender == bridge, "NOT_FROM_BRIDGE");
                            // and the outbox reports that the L2 address of the sender is the counterpart gateway
                            address l2ToL1Sender = super.getL2ToL1Sender(_inbox);
                            require(l2ToL1Sender == counterpartGateway, "ONLY_COUNTERPART_GATEWAY");
                            _;
                        }
                        function postUpgradeInit() external {
                            // it is assumed the L1 Arbitrum Gateway contract is behind a Proxy controlled by a proxy admin
                            // this function can only be called by the proxy admin contract
                            address proxyAdmin = ProxyUtil.getProxyAdmin();
                            require(msg.sender == proxyAdmin, "NOT_FROM_ADMIN");
                            // this has no other logic since the current upgrade doesn't require this logic
                        }
                        function _initialize(
                            address _l2Counterpart,
                            address _router,
                            address _inbox
                        ) internal virtual {
                            TokenGateway._initialize(_l2Counterpart, _router);
                            // L1 gateway must have a router
                            require(_router != address(0), "BAD_ROUTER");
                            require(_inbox != address(0), "BAD_INBOX");
                            inbox = _inbox;
                        }
                        /**
                         * @notice Finalizes a withdrawal via Outbox message; callable only by L2Gateway.outboundTransfer
                         * @param _token L1 address of token being withdrawn from
                         * @param _from initiator of withdrawal
                         * @param _to address the L2 withdrawal call set as the destination.
                         * @param _amount Token amount being withdrawn
                         * @param _data encoded exitNum (Sequentially increasing exit counter determined by the L2Gateway) and additinal hook data
                         */
                        function finalizeInboundTransfer(
                            address _token,
                            address _from,
                            address _to,
                            uint256 _amount,
                            bytes calldata _data
                        ) external payable override onlyCounterpartGateway {
                            (uint256 exitNum, bytes memory callHookData) = GatewayMessageHandler.parseToL1GatewayMsg(
                                _data
                            );
                            if (callHookData.length != 0) {
                                // callHookData should always be 0 since inboundEscrowAndCall is disabled
                                callHookData = bytes("");
                            }
                            // we ignore the returned data since the callHook feature is now disabled
                            (_to, ) = getExternalCall(exitNum, _to, callHookData);
                            inboundEscrowTransfer(_token, _to, _amount);
                            emit WithdrawalFinalized(_token, _from, _to, exitNum, _amount);
                        }
                        function getExternalCall(
                            uint256, /* _exitNum */
                            address _initialDestination,
                            bytes memory _initialData
                        ) public view virtual returns (address target, bytes memory data) {
                            // this method is virtual so the destination of a call can be changed
                            // using tradeable exits in a subclass (L1ArbitrumExtendedGateway)
                            target = _initialDestination;
                            data = _initialData;
                        }
                        function inboundEscrowTransfer(
                            address _l1Token,
                            address _dest,
                            uint256 _amount
                        ) internal virtual {
                            // this method is virtual since different subclasses can handle escrow differently
                            IERC20(_l1Token).safeTransfer(_dest, _amount);
                        }
                        function createOutboundTx(
                            address _from,
                            uint256, /* _tokenAmount */
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            uint256 _maxSubmissionCost,
                            bytes memory _outboundCalldata
                        ) internal virtual returns (uint256) {
                            // We make this function virtual since outboundTransfer logic is the same for many gateways
                            // but sometimes (ie weth) you construct the outgoing message differently.
                            // msg.value is sent, but 0 is set to the L2 call value
                            // the eth sent is used to pay for the tx's gas
                            return
                                sendTxToL2(
                                    inbox,
                                    counterpartGateway,
                                    _from,
                                    msg.value, // we forward the L1 call value to the inbox
                                    0, // l2 call value 0 by default
                                    L2GasParams({
                                        _maxSubmissionCost: _maxSubmissionCost,
                                        _maxGas: _maxGas,
                                        _gasPriceBid: _gasPriceBid
                                    }),
                                    _outboundCalldata
                                );
                        }
                        /**
                         * @notice Deposit ERC20 token from Ethereum into Arbitrum. If L2 side hasn't been deployed yet, includes name/symbol/decimals data for initial L2 deploy. Initiate by GatewayRouter.
                         * @param _l1Token L1 address of ERC20
                         * @param _to account to be credited with the tokens in the L2 (can be the user's L2 account or a contract)
                         * @param _amount Token Amount
                         * @param _maxGas Max gas deducted from user's L2 balance to cover L2 execution
                         * @param _gasPriceBid Gas price for L2 execution
                         * @param _data encoded data from router and user
                         * @return res abi encoded inbox sequence number
                         */
                        //  * @param maxSubmissionCost Max gas deducted from user's L2 balance to cover base submission fee
                        function outboundTransfer(
                            address _l1Token,
                            address _to,
                            uint256 _amount,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            bytes calldata _data
                        ) public payable virtual override returns (bytes memory res) {
                            require(isRouter(msg.sender), "NOT_FROM_ROUTER");
                            // This function is set as public and virtual so that subclasses can override
                            // it and add custom validation for callers (ie only whitelisted users)
                            address _from;
                            uint256 seqNum;
                            bytes memory extraData;
                            {
                                uint256 _maxSubmissionCost;
                                if (super.isRouter(msg.sender)) {
                                    // router encoded
                                    (_from, extraData) = GatewayMessageHandler.parseFromRouterToGateway(_data);
                                } else {
                                    _from = msg.sender;
                                    extraData = _data;
                                }
                                // user encoded
                                (_maxSubmissionCost, extraData) = abi.decode(extraData, (uint256, bytes));
                                // the inboundEscrowAndCall functionality has been disabled, so no data is allowed
                                require(extraData.length == 0, "EXTRA_DATA_DISABLED");
                                require(_l1Token.isContract(), "L1_NOT_CONTRACT");
                                address l2Token = calculateL2TokenAddress(_l1Token);
                                require(l2Token != address(0), "NO_L2_TOKEN_SET");
                                _amount = outboundEscrowTransfer(_l1Token, _from, _amount);
                                // we override the res field to save on the stack
                                res = getOutboundCalldata(_l1Token, _from, _to, _amount, extraData);
                                seqNum = createOutboundTx(
                                    _from,
                                    _amount,
                                    _maxGas,
                                    _gasPriceBid,
                                    _maxSubmissionCost,
                                    res
                                );
                            }
                            emit DepositInitiated(_l1Token, _from, _to, seqNum, _amount);
                            return abi.encode(seqNum);
                        }
                        function outboundEscrowTransfer(
                            address _l1Token,
                            address _from,
                            uint256 _amount
                        ) internal virtual returns (uint256 amountReceived) {
                            // this method is virtual since different subclasses can handle escrow differently
                            // user funds are escrowed on the gateway using this function
                            uint256 prevBalance = IERC20(_l1Token).balanceOf(address(this));
                            IERC20(_l1Token).safeTransferFrom(_from, address(this), _amount);
                            uint256 postBalance = IERC20(_l1Token).balanceOf(address(this));
                            return SafeMath.sub(postBalance, prevBalance);
                        }
                        function getOutboundCalldata(
                            address _l1Token,
                            address _from,
                            address _to,
                            uint256 _amount,
                            bytes memory _data
                        ) public view virtual override returns (bytes memory outboundCalldata) {
                            // this function is public so users can query how much calldata will be sent to the L2
                            // before execution
                            // it is virtual since different gateway subclasses can build this calldata differently
                            // ( ie the standard ERC20 gateway queries for a tokens name/symbol/decimals )
                            bytes memory emptyBytes = "";
                            outboundCalldata = abi.encodeWithSelector(
                                TokenGateway.finalizeInboundTransfer.selector,
                                _l1Token,
                                _from,
                                _to,
                                _amount,
                                GatewayMessageHandler.encodeToL2GatewayMsg(emptyBytes, _data)
                            );
                            return outboundCalldata;
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /**
                     * @dev Interface of the ERC20 standard as defined in the EIP.
                     */
                    interface IERC20Upgradeable {
                        /**
                         * @dev Returns the amount of tokens in existence.
                         */
                        function totalSupply() external view returns (uint256);
                        /**
                         * @dev Returns the amount of tokens owned by `account`.
                         */
                        function balanceOf(address account) external view returns (uint256);
                        /**
                         * @dev Moves `amount` tokens from the caller's account to `recipient`.
                         *
                         * Returns a boolean value indicating whether the operation succeeded.
                         *
                         * Emits a {Transfer} event.
                         */
                        function transfer(address recipient, uint256 amount) external returns (bool);
                        /**
                         * @dev Returns the remaining number of tokens that `spender` will be
                         * allowed to spend on behalf of `owner` through {transferFrom}. This is
                         * zero by default.
                         *
                         * This value changes when {approve} or {transferFrom} are called.
                         */
                        function allowance(address owner, address spender) external view returns (uint256);
                        /**
                         * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
                         *
                         * Returns a boolean value indicating whether the operation succeeded.
                         *
                         * IMPORTANT: Beware that changing an allowance with this method brings the risk
                         * that someone may use both the old and the new allowance by unfortunate
                         * transaction ordering. One possible solution to mitigate this race
                         * condition is to first reduce the spender's allowance to 0 and set the
                         * desired value afterwards:
                         * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
                         *
                         * Emits an {Approval} event.
                         */
                        function approve(address spender, uint256 amount) external returns (bool);
                        /**
                         * @dev Moves `amount` tokens from `sender` to `recipient` using the
                         * allowance mechanism. `amount` is then deducted from the caller's
                         * allowance.
                         *
                         * Returns a boolean value indicating whether the operation succeeded.
                         *
                         * Emits a {Transfer} event.
                         */
                        function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
                        /**
                         * @dev Emitted when `value` tokens are moved from one account (`from`) to
                         * another (`to`).
                         *
                         * Note that `value` may be zero.
                         */
                        event Transfer(address indexed from, address indexed to, uint256 value);
                        /**
                         * @dev Emitted when the allowance of a `spender` for an `owner` is set by
                         * a call to {approve}. `value` is the new allowance.
                         */
                        event Approval(address indexed owner, address indexed spender, uint256 value);
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "../../utils/Context.sol";
                    import "./IERC20.sol";
                    import "../../math/SafeMath.sol";
                    /**
                     * @dev Implementation of the {IERC20} interface.
                     *
                     * This implementation is agnostic to the way tokens are created. This means
                     * that a supply mechanism has to be added in a derived contract using {_mint}.
                     * For a generic mechanism see {ERC20PresetMinterPauser}.
                     *
                     * TIP: For a detailed writeup see our guide
                     * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
                     * to implement supply mechanisms].
                     *
                     * We have followed general OpenZeppelin guidelines: functions revert instead
                     * of returning `false` on failure. This behavior is nonetheless conventional
                     * and does not conflict with the expectations of ERC20 applications.
                     *
                     * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
                     * This allows applications to reconstruct the allowance for all accounts just
                     * by listening to said events. Other implementations of the EIP may not emit
                     * these events, as it isn't required by the specification.
                     *
                     * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
                     * functions have been added to mitigate the well-known issues around setting
                     * allowances. See {IERC20-approve}.
                     */
                    contract ERC20 is Context, IERC20 {
                        using SafeMath for uint256;
                        mapping (address => uint256) private _balances;
                        mapping (address => mapping (address => uint256)) private _allowances;
                        uint256 private _totalSupply;
                        string private _name;
                        string private _symbol;
                        uint8 private _decimals;
                        /**
                         * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
                         * a default value of 18.
                         *
                         * To select a different value for {decimals}, use {_setupDecimals}.
                         *
                         * All three of these values are immutable: they can only be set once during
                         * construction.
                         */
                        constructor (string memory name_, string memory symbol_) public {
                            _name = name_;
                            _symbol = symbol_;
                            _decimals = 18;
                        }
                        /**
                         * @dev Returns the name of the token.
                         */
                        function name() public view virtual returns (string memory) {
                            return _name;
                        }
                        /**
                         * @dev Returns the symbol of the token, usually a shorter version of the
                         * name.
                         */
                        function symbol() public view virtual returns (string memory) {
                            return _symbol;
                        }
                        /**
                         * @dev Returns the number of decimals used to get its user representation.
                         * For example, if `decimals` equals `2`, a balance of `505` tokens should
                         * be displayed to a user as `5,05` (`505 / 10 ** 2`).
                         *
                         * Tokens usually opt for a value of 18, imitating the relationship between
                         * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
                         * called.
                         *
                         * NOTE: This information is only used for _display_ purposes: it in
                         * no way affects any of the arithmetic of the contract, including
                         * {IERC20-balanceOf} and {IERC20-transfer}.
                         */
                        function decimals() public view virtual returns (uint8) {
                            return _decimals;
                        }
                        /**
                         * @dev See {IERC20-totalSupply}.
                         */
                        function totalSupply() public view virtual override returns (uint256) {
                            return _totalSupply;
                        }
                        /**
                         * @dev See {IERC20-balanceOf}.
                         */
                        function balanceOf(address account) public view virtual override returns (uint256) {
                            return _balances[account];
                        }
                        /**
                         * @dev See {IERC20-transfer}.
                         *
                         * Requirements:
                         *
                         * - `recipient` cannot be the zero address.
                         * - the caller must have a balance of at least `amount`.
                         */
                        function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
                            _transfer(_msgSender(), recipient, amount);
                            return true;
                        }
                        /**
                         * @dev See {IERC20-allowance}.
                         */
                        function allowance(address owner, address spender) public view virtual override returns (uint256) {
                            return _allowances[owner][spender];
                        }
                        /**
                         * @dev See {IERC20-approve}.
                         *
                         * Requirements:
                         *
                         * - `spender` cannot be the zero address.
                         */
                        function approve(address spender, uint256 amount) public virtual override returns (bool) {
                            _approve(_msgSender(), spender, amount);
                            return true;
                        }
                        /**
                         * @dev See {IERC20-transferFrom}.
                         *
                         * Emits an {Approval} event indicating the updated allowance. This is not
                         * required by the EIP. See the note at the beginning of {ERC20}.
                         *
                         * Requirements:
                         *
                         * - `sender` and `recipient` cannot be the zero address.
                         * - `sender` must have a balance of at least `amount`.
                         * - the caller must have allowance for ``sender``'s tokens of at least
                         * `amount`.
                         */
                        function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
                            _transfer(sender, recipient, amount);
                            _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
                            return true;
                        }
                        /**
                         * @dev Atomically increases the allowance granted to `spender` by the caller.
                         *
                         * This is an alternative to {approve} that can be used as a mitigation for
                         * problems described in {IERC20-approve}.
                         *
                         * Emits an {Approval} event indicating the updated allowance.
                         *
                         * Requirements:
                         *
                         * - `spender` cannot be the zero address.
                         */
                        function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
                            _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
                            return true;
                        }
                        /**
                         * @dev Atomically decreases the allowance granted to `spender` by the caller.
                         *
                         * This is an alternative to {approve} that can be used as a mitigation for
                         * problems described in {IERC20-approve}.
                         *
                         * Emits an {Approval} event indicating the updated allowance.
                         *
                         * Requirements:
                         *
                         * - `spender` cannot be the zero address.
                         * - `spender` must have allowance for the caller of at least
                         * `subtractedValue`.
                         */
                        function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
                            _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
                            return true;
                        }
                        /**
                         * @dev Moves tokens `amount` from `sender` to `recipient`.
                         *
                         * This is internal function is equivalent to {transfer}, and can be used to
                         * e.g. implement automatic token fees, slashing mechanisms, etc.
                         *
                         * Emits a {Transfer} event.
                         *
                         * Requirements:
                         *
                         * - `sender` cannot be the zero address.
                         * - `recipient` cannot be the zero address.
                         * - `sender` must have a balance of at least `amount`.
                         */
                        function _transfer(address sender, address recipient, uint256 amount) internal virtual {
                            require(sender != address(0), "ERC20: transfer from the zero address");
                            require(recipient != address(0), "ERC20: transfer to the zero address");
                            _beforeTokenTransfer(sender, recipient, amount);
                            _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
                            _balances[recipient] = _balances[recipient].add(amount);
                            emit Transfer(sender, recipient, amount);
                        }
                        /** @dev Creates `amount` tokens and assigns them to `account`, increasing
                         * the total supply.
                         *
                         * Emits a {Transfer} event with `from` set to the zero address.
                         *
                         * Requirements:
                         *
                         * - `to` cannot be the zero address.
                         */
                        function _mint(address account, uint256 amount) internal virtual {
                            require(account != address(0), "ERC20: mint to the zero address");
                            _beforeTokenTransfer(address(0), account, amount);
                            _totalSupply = _totalSupply.add(amount);
                            _balances[account] = _balances[account].add(amount);
                            emit Transfer(address(0), account, amount);
                        }
                        /**
                         * @dev Destroys `amount` tokens from `account`, reducing the
                         * total supply.
                         *
                         * Emits a {Transfer} event with `to` set to the zero address.
                         *
                         * Requirements:
                         *
                         * - `account` cannot be the zero address.
                         * - `account` must have at least `amount` tokens.
                         */
                        function _burn(address account, uint256 amount) internal virtual {
                            require(account != address(0), "ERC20: burn from the zero address");
                            _beforeTokenTransfer(account, address(0), amount);
                            _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
                            _totalSupply = _totalSupply.sub(amount);
                            emit Transfer(account, address(0), amount);
                        }
                        /**
                         * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
                         *
                         * This internal function is equivalent to `approve`, and can be used to
                         * e.g. set automatic allowances for certain subsystems, etc.
                         *
                         * Emits an {Approval} event.
                         *
                         * Requirements:
                         *
                         * - `owner` cannot be the zero address.
                         * - `spender` cannot be the zero address.
                         */
                        function _approve(address owner, address spender, uint256 amount) internal virtual {
                            require(owner != address(0), "ERC20: approve from the zero address");
                            require(spender != address(0), "ERC20: approve to the zero address");
                            _allowances[owner][spender] = amount;
                            emit Approval(owner, spender, amount);
                        }
                        /**
                         * @dev Sets {decimals} to a value other than the default one of 18.
                         *
                         * WARNING: This function should only be called from the constructor. Most
                         * applications that interact with token contracts will not expect
                         * {decimals} to ever change, and may work incorrectly if it does.
                         */
                        function _setupDecimals(uint8 decimals_) internal virtual {
                            _decimals = decimals_;
                        }
                        /**
                         * @dev Hook that is called before any transfer of tokens. This includes
                         * minting and burning.
                         *
                         * Calling conditions:
                         *
                         * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
                         * will be to transferred to `to`.
                         * - when `from` is zero, `amount` tokens will be minted for `to`.
                         * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
                         * - `from` and `to` are never both zero.
                         *
                         * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
                         */
                        function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "./IERC20.sol";
                    import "../../math/SafeMath.sol";
                    import "../../utils/Address.sol";
                    /**
                     * @title SafeERC20
                     * @dev Wrappers around ERC20 operations that throw on failure (when the token
                     * contract returns false). Tokens that return no value (and instead revert or
                     * throw on failure) are also supported, non-reverting calls are assumed to be
                     * successful.
                     * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
                     * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
                     */
                    library SafeERC20 {
                        using SafeMath for uint256;
                        using Address for address;
                        function safeTransfer(IERC20 token, address to, uint256 value) internal {
                            _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
                        }
                        function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
                            _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
                        }
                        /**
                         * @dev Deprecated. This function has issues similar to the ones found in
                         * {IERC20-approve}, and its usage is discouraged.
                         *
                         * Whenever possible, use {safeIncreaseAllowance} and
                         * {safeDecreaseAllowance} instead.
                         */
                        function safeApprove(IERC20 token, address spender, uint256 value) internal {
                            // safeApprove should only be called when setting an initial allowance,
                            // or when resetting it to zero. To increase and decrease it, use
                            // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
                            // solhint-disable-next-line max-line-length
                            require((value == 0) || (token.allowance(address(this), spender) == 0),
                                "SafeERC20: approve from non-zero to non-zero allowance"
                            );
                            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
                        }
                        function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
                            uint256 newAllowance = token.allowance(address(this), spender).add(value);
                            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
                        }
                        function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
                            uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
                            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
                        }
                        /**
                         * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
                         * on the return value: the return value is optional (but if data is returned, it must not be false).
                         * @param token The token targeted by the call.
                         * @param data The call data (encoded using abi.encode or one of its variants).
                         */
                        function _callOptionalReturn(IERC20 token, bytes memory data) private {
                            // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
                            // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
                            // the target address contains contract code and also asserts for success in the low-level call.
                            bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
                            if (returndata.length > 0) { // Return data is optional
                                // solhint-disable-next-line max-line-length
                                require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
                            }
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /**
                     * @dev Helper to make usage of the `CREATE2` EVM opcode easier and safer.
                     * `CREATE2` can be used to compute in advance the address where a smart
                     * contract will be deployed, which allows for interesting new mechanisms known
                     * as 'counterfactual interactions'.
                     *
                     * See the https://eips.ethereum.org/EIPS/eip-1014#motivation[EIP] for more
                     * information.
                     */
                    library Create2 {
                        /**
                         * @dev Deploys a contract using `CREATE2`. The address where the contract
                         * will be deployed can be known in advance via {computeAddress}.
                         *
                         * The bytecode for a contract can be obtained from Solidity with
                         * `type(contractName).creationCode`.
                         *
                         * Requirements:
                         *
                         * - `bytecode` must not be empty.
                         * - `salt` must have not been used for `bytecode` already.
                         * - the factory must have a balance of at least `amount`.
                         * - if `amount` is non-zero, `bytecode` must have a `payable` constructor.
                         */
                        function deploy(uint256 amount, bytes32 salt, bytes memory bytecode) internal returns (address) {
                            address addr;
                            require(address(this).balance >= amount, "Create2: insufficient balance");
                            require(bytecode.length != 0, "Create2: bytecode length is zero");
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                addr := create2(amount, add(bytecode, 0x20), mload(bytecode), salt)
                            }
                            require(addr != address(0), "Create2: Failed on deploy");
                            return addr;
                        }
                        /**
                         * @dev Returns the address where a contract will be stored if deployed via {deploy}. Any change in the
                         * `bytecodeHash` or `salt` will result in a new destination address.
                         */
                        function computeAddress(bytes32 salt, bytes32 bytecodeHash) internal view returns (address) {
                            return computeAddress(salt, bytecodeHash, address(this));
                        }
                        /**
                         * @dev Returns the address where a contract will be stored if deployed via {deploy} from a contract located at
                         * `deployer`. If `deployer` is this contract's address, returns the same value as {computeAddress}.
                         */
                        function computeAddress(bytes32 salt, bytes32 bytecodeHash, address deployer) internal pure returns (address) {
                            bytes32 _data = keccak256(
                                abi.encodePacked(bytes1(0xff), deployer, salt, bytecodeHash)
                            );
                            return address(uint160(uint256(_data)));
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /**
                     * @dev Wrappers over Solidity's arithmetic operations with added overflow
                     * checks.
                     *
                     * Arithmetic operations in Solidity wrap on overflow. This can easily result
                     * in bugs, because programmers usually assume that an overflow raises an
                     * error, which is the standard behavior in high level programming languages.
                     * `SafeMath` restores this intuition by reverting the transaction when an
                     * operation overflows.
                     *
                     * Using this library instead of the unchecked operations eliminates an entire
                     * class of bugs, so it's recommended to use it always.
                     */
                    library SafeMath {
                        /**
                         * @dev Returns the addition of two unsigned integers, with an overflow flag.
                         *
                         * _Available since v3.4._
                         */
                        function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                            uint256 c = a + b;
                            if (c < a) return (false, 0);
                            return (true, c);
                        }
                        /**
                         * @dev Returns the substraction of two unsigned integers, with an overflow flag.
                         *
                         * _Available since v3.4._
                         */
                        function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                            if (b > a) return (false, 0);
                            return (true, a - b);
                        }
                        /**
                         * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
                         *
                         * _Available since v3.4._
                         */
                        function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
                            // benefit is lost if 'b' is also tested.
                            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
                            if (a == 0) return (true, 0);
                            uint256 c = a * b;
                            if (c / a != b) return (false, 0);
                            return (true, c);
                        }
                        /**
                         * @dev Returns the division of two unsigned integers, with a division by zero flag.
                         *
                         * _Available since v3.4._
                         */
                        function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                            if (b == 0) return (false, 0);
                            return (true, a / b);
                        }
                        /**
                         * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
                         *
                         * _Available since v3.4._
                         */
                        function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                            if (b == 0) return (false, 0);
                            return (true, a % b);
                        }
                        /**
                         * @dev Returns the addition of two unsigned integers, reverting on
                         * overflow.
                         *
                         * Counterpart to Solidity's `+` operator.
                         *
                         * Requirements:
                         *
                         * - Addition cannot overflow.
                         */
                        function add(uint256 a, uint256 b) internal pure returns (uint256) {
                            uint256 c = a + b;
                            require(c >= a, "SafeMath: addition overflow");
                            return c;
                        }
                        /**
                         * @dev Returns the subtraction of two unsigned integers, reverting on
                         * overflow (when the result is negative).
                         *
                         * Counterpart to Solidity's `-` operator.
                         *
                         * Requirements:
                         *
                         * - Subtraction cannot overflow.
                         */
                        function sub(uint256 a, uint256 b) internal pure returns (uint256) {
                            require(b <= a, "SafeMath: subtraction overflow");
                            return a - b;
                        }
                        /**
                         * @dev Returns the multiplication of two unsigned integers, reverting on
                         * overflow.
                         *
                         * Counterpart to Solidity's `*` operator.
                         *
                         * Requirements:
                         *
                         * - Multiplication cannot overflow.
                         */
                        function mul(uint256 a, uint256 b) internal pure returns (uint256) {
                            if (a == 0) return 0;
                            uint256 c = a * b;
                            require(c / a == b, "SafeMath: multiplication overflow");
                            return c;
                        }
                        /**
                         * @dev Returns the integer division of two unsigned integers, reverting on
                         * division by zero. The result is rounded towards zero.
                         *
                         * Counterpart to Solidity's `/` operator. Note: this function uses a
                         * `revert` opcode (which leaves remaining gas untouched) while Solidity
                         * uses an invalid opcode to revert (consuming all remaining gas).
                         *
                         * Requirements:
                         *
                         * - The divisor cannot be zero.
                         */
                        function div(uint256 a, uint256 b) internal pure returns (uint256) {
                            require(b > 0, "SafeMath: division by zero");
                            return a / b;
                        }
                        /**
                         * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                         * reverting when dividing by zero.
                         *
                         * Counterpart to Solidity's `%` operator. This function uses a `revert`
                         * opcode (which leaves remaining gas untouched) while Solidity uses an
                         * invalid opcode to revert (consuming all remaining gas).
                         *
                         * Requirements:
                         *
                         * - The divisor cannot be zero.
                         */
                        function mod(uint256 a, uint256 b) internal pure returns (uint256) {
                            require(b > 0, "SafeMath: modulo by zero");
                            return a % b;
                        }
                        /**
                         * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
                         * overflow (when the result is negative).
                         *
                         * CAUTION: This function is deprecated because it requires allocating memory for the error
                         * message unnecessarily. For custom revert reasons use {trySub}.
                         *
                         * Counterpart to Solidity's `-` operator.
                         *
                         * Requirements:
                         *
                         * - Subtraction cannot overflow.
                         */
                        function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                            require(b <= a, errorMessage);
                            return a - b;
                        }
                        /**
                         * @dev Returns the integer division of two unsigned integers, reverting with custom message on
                         * division by zero. The result is rounded towards zero.
                         *
                         * CAUTION: This function is deprecated because it requires allocating memory for the error
                         * message unnecessarily. For custom revert reasons use {tryDiv}.
                         *
                         * Counterpart to Solidity's `/` operator. Note: this function uses a
                         * `revert` opcode (which leaves remaining gas untouched) while Solidity
                         * uses an invalid opcode to revert (consuming all remaining gas).
                         *
                         * Requirements:
                         *
                         * - The divisor cannot be zero.
                         */
                        function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                            require(b > 0, errorMessage);
                            return a / b;
                        }
                        /**
                         * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                         * reverting with custom message when dividing by zero.
                         *
                         * CAUTION: This function is deprecated because it requires allocating memory for the error
                         * message unnecessarily. For custom revert reasons use {tryMod}.
                         *
                         * Counterpart to Solidity's `%` operator. This function uses a `revert`
                         * opcode (which leaves remaining gas untouched) while Solidity uses an
                         * invalid opcode to revert (consuming all remaining gas).
                         *
                         * Requirements:
                         *
                         * - The divisor cannot be zero.
                         */
                        function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                            require(b > 0, errorMessage);
                            return a % b;
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "./IBridge.sol";
                    import "./IMessageProvider.sol";
                    interface IInbox is IMessageProvider {
                        function sendL2Message(bytes calldata messageData) external returns (uint256);
                        function sendUnsignedTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            uint256 nonce,
                            address destAddr,
                            uint256 amount,
                            bytes calldata data
                        ) external returns (uint256);
                        function sendContractTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            address destAddr,
                            uint256 amount,
                            bytes calldata data
                        ) external returns (uint256);
                        function sendL1FundedUnsignedTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            uint256 nonce,
                            address destAddr,
                            bytes calldata data
                        ) external payable returns (uint256);
                        function sendL1FundedContractTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            address destAddr,
                            bytes calldata data
                        ) external payable returns (uint256);
                        function createRetryableTicket(
                            address destAddr,
                            uint256 arbTxCallValue,
                            uint256 maxSubmissionCost,
                            address submissionRefundAddress,
                            address valueRefundAddress,
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            bytes calldata data
                        ) external payable returns (uint256);
                        function depositEth(uint256 maxSubmissionCost) external payable returns (uint256);
                        function bridge() external view returns (IBridge);
                        function pauseEthDeposits() external;
                        function unpauseEthDeposits() external;
                        function startRewriteAddress() external;
                        function stopRewriteAddress() external;
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    library ProxyUtil {
                        function getProxyAdmin() internal view returns (address admin) {
                            // https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v3.4.0/contracts/proxy/TransparentUpgradeableProxy.sol#L48
                            // Storage slot with the admin of the proxy contract.
                            // This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
                            bytes32 slot = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
                            assembly {
                                admin := sload(slot)
                            }
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "arb-bridge-eth/contracts/bridge/interfaces/IInbox.sol";
                    import "arb-bridge-eth/contracts/bridge/interfaces/IOutbox.sol";
                    /// @notice L1 utility contract to assist with L1 <=> L2 interactions
                    /// @dev this is an abstract contract instead of library so the functions can be easily overriden when testing
                    abstract contract L1ArbitrumMessenger {
                        event TxToL2(address indexed _from, address indexed _to, uint256 indexed _seqNum, bytes _data);
                        struct L2GasParams {
                            uint256 _maxSubmissionCost;
                            uint256 _maxGas;
                            uint256 _gasPriceBid;
                        }
                        function sendTxToL2(
                            address _inbox,
                            address _to,
                            address _user,
                            uint256 _l1CallValue,
                            uint256 _l2CallValue,
                            L2GasParams memory _l2GasParams,
                            bytes memory _data
                        ) internal virtual returns (uint256) {
                            // alternative function entry point when struggling with the stack size
                            return
                                sendTxToL2(
                                    _inbox,
                                    _to,
                                    _user,
                                    _l1CallValue,
                                    _l2CallValue,
                                    _l2GasParams._maxSubmissionCost,
                                    _l2GasParams._maxGas,
                                    _l2GasParams._gasPriceBid,
                                    _data
                                );
                        }
                        function sendTxToL2(
                            address _inbox,
                            address _to,
                            address _user,
                            uint256 _l1CallValue,
                            uint256 _l2CallValue,
                            uint256 _maxSubmissionCost,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            bytes memory _data
                        ) internal virtual returns (uint256) {
                            uint256 seqNum = IInbox(_inbox).createRetryableTicket{ value: _l1CallValue }(
                                _to,
                                _l2CallValue,
                                _maxSubmissionCost,
                                _user,
                                _user,
                                _maxGas,
                                _gasPriceBid,
                                _data
                            );
                            emit TxToL2(_user, _to, seqNum, _data);
                            return seqNum;
                        }
                        function getBridge(address _inbox) internal view virtual returns (IBridge) {
                            return IInbox(_inbox).bridge();
                        }
                        /// @dev the l2ToL1Sender behaves as the tx.origin, the msg.sender should be validated to protect against reentrancies
                        function getL2ToL1Sender(address _inbox) internal view virtual returns (address) {
                            IOutbox outbox = IOutbox(getBridge(_inbox).activeOutbox());
                            address l2ToL1Sender = outbox.l2ToL1Sender();
                            require(l2ToL1Sender != address(0), "NO_SENDER");
                            return l2ToL1Sender;
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    /// @notice this library manages encoding and decoding of gateway communication
                    library GatewayMessageHandler {
                        // these are for communication from L1 to L2 gateway
                        function encodeToL2GatewayMsg(bytes memory gatewayData, bytes memory callHookData)
                            internal
                            pure
                            returns (bytes memory res)
                        {
                            res = abi.encode(gatewayData, callHookData);
                        }
                        function parseFromL1GatewayMsg(bytes calldata _data)
                            internal
                            pure
                            returns (bytes memory gatewayData, bytes memory callHookData)
                        {
                            // abi decode may revert, but the encoding is done by L1 gateway, so we trust it
                            (gatewayData, callHookData) = abi.decode(_data, (bytes, bytes));
                        }
                        // these are for communication from L2 to L1 gateway
                        function encodeFromL2GatewayMsg(uint256 exitNum, bytes memory callHookData)
                            internal
                            pure
                            returns (bytes memory res)
                        {
                            res = abi.encode(exitNum, callHookData);
                        }
                        function parseToL1GatewayMsg(bytes calldata _data)
                            internal
                            pure
                            returns (uint256 exitNum, bytes memory callHookData)
                        {
                            // abi decode may revert, but the encoding is done by L1 gateway, so we trust it
                            (exitNum, callHookData) = abi.decode(_data, (uint256, bytes));
                        }
                        // these are for communication from router to gateway
                        function encodeFromRouterToGateway(address _from, bytes calldata _data)
                            internal
                            pure
                            returns (bytes memory res)
                        {
                            // abi decode may revert, but the encoding is done by L1 gateway, so we trust it
                            return abi.encode(_from, _data);
                        }
                        function parseFromRouterToGateway(bytes calldata _data)
                            internal
                            pure
                            returns (address, bytes memory res)
                        {
                            // abi decode may revert, but the encoding is done by L1 gateway, so we trust it
                            return abi.decode(_data, (address, bytes));
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "./ITokenGateway.sol";
                    import "@openzeppelin/contracts/utils/Address.sol";
                    abstract contract TokenGateway is ITokenGateway {
                        using Address for address;
                        address public counterpartGateway;
                        address public router;
                        modifier onlyCounterpartGateway() virtual {
                            // this method is overriden in gateways that require special logic for validation
                            // ie L2 to L1 messages need to be validated against the outbox
                            require(msg.sender == counterpartGateway, "ONLY_COUNTERPART_GATEWAY");
                            _;
                        }
                        function _initialize(address _counterpartGateway, address _router) internal virtual {
                            // This initializes internal variables of the abstract contract it can be chained together with other functions.
                            // It is virtual so subclasses can override or wrap around this logic.
                            // An example where this is useful is different subclasses that validate the router address differently
                            require(_counterpartGateway != address(0), "INVALID_COUNTERPART");
                            require(counterpartGateway == address(0), "ALREADY_INIT");
                            counterpartGateway = _counterpartGateway;
                            router = _router;
                        }
                        function isRouter(address _target) internal view returns (bool isTargetRouter) {
                            return _target == router;
                        }
                        /**
                         * @notice Calculate the address used when bridging an ERC20 token
                         * @dev the L1 and L2 address oracles may not always be in sync.
                         * For example, a custom token may have been registered but not deploy or the contract self destructed.
                         * @param l1ERC20 address of L1 token
                         * @return L2 address of a bridged ERC20 token
                         */
                        function calculateL2TokenAddress(address l1ERC20)
                            public
                            view
                            virtual
                            override
                            returns (address);
                        function outboundTransfer(
                            address _token,
                            address _to,
                            uint256 _amount,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            bytes calldata _data
                        ) external payable virtual override returns (bytes memory);
                        function getOutboundCalldata(
                            address _token,
                            address _from,
                            address _to,
                            uint256 _amount,
                            bytes memory _data
                        ) public view virtual returns (bytes memory);
                        function finalizeInboundTransfer(
                            address _token,
                            address _from,
                            address _to,
                            uint256 _amount,
                            bytes calldata _data
                        ) external payable virtual override;
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /*
                     * @dev Provides information about the current execution context, including the
                     * sender of the transaction and its data. While these are generally available
                     * via msg.sender and msg.data, they should not be accessed in such a direct
                     * manner, since when dealing with GSN meta-transactions the account sending and
                     * paying for execution may not be the actual sender (as far as an application
                     * is concerned).
                     *
                     * This contract is only required for intermediate, library-like contracts.
                     */
                    abstract contract Context {
                        function _msgSender() internal view virtual returns (address payable) {
                            return msg.sender;
                        }
                        function _msgData() internal view virtual returns (bytes memory) {
                            this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
                            return msg.data;
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /**
                     * @dev Interface of the ERC20 standard as defined in the EIP.
                     */
                    interface IERC20 {
                        /**
                         * @dev Returns the amount of tokens in existence.
                         */
                        function totalSupply() external view returns (uint256);
                        /**
                         * @dev Returns the amount of tokens owned by `account`.
                         */
                        function balanceOf(address account) external view returns (uint256);
                        /**
                         * @dev Moves `amount` tokens from the caller's account to `recipient`.
                         *
                         * Returns a boolean value indicating whether the operation succeeded.
                         *
                         * Emits a {Transfer} event.
                         */
                        function transfer(address recipient, uint256 amount) external returns (bool);
                        /**
                         * @dev Returns the remaining number of tokens that `spender` will be
                         * allowed to spend on behalf of `owner` through {transferFrom}. This is
                         * zero by default.
                         *
                         * This value changes when {approve} or {transferFrom} are called.
                         */
                        function allowance(address owner, address spender) external view returns (uint256);
                        /**
                         * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
                         *
                         * Returns a boolean value indicating whether the operation succeeded.
                         *
                         * IMPORTANT: Beware that changing an allowance with this method brings the risk
                         * that someone may use both the old and the new allowance by unfortunate
                         * transaction ordering. One possible solution to mitigate this race
                         * condition is to first reduce the spender's allowance to 0 and set the
                         * desired value afterwards:
                         * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
                         *
                         * Emits an {Approval} event.
                         */
                        function approve(address spender, uint256 amount) external returns (bool);
                        /**
                         * @dev Moves `amount` tokens from `sender` to `recipient` using the
                         * allowance mechanism. `amount` is then deducted from the caller's
                         * allowance.
                         *
                         * Returns a boolean value indicating whether the operation succeeded.
                         *
                         * Emits a {Transfer} event.
                         */
                        function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
                        /**
                         * @dev Emitted when `value` tokens are moved from one account (`from`) to
                         * another (`to`).
                         *
                         * Note that `value` may be zero.
                         */
                        event Transfer(address indexed from, address indexed to, uint256 value);
                        /**
                         * @dev Emitted when the allowance of a `spender` for an `owner` is set by
                         * a call to {approve}. `value` is the new allowance.
                         */
                        event Approval(address indexed owner, address indexed spender, uint256 value);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface IBridge {
                        event MessageDelivered(
                            uint256 indexed messageIndex,
                            bytes32 indexed beforeInboxAcc,
                            address inbox,
                            uint8 kind,
                            address sender,
                            bytes32 messageDataHash
                        );
                        event BridgeCallTriggered(
                            address indexed outbox,
                            address indexed destAddr,
                            uint256 amount,
                            bytes data
                        );
                        event InboxToggle(address indexed inbox, bool enabled);
                        event OutboxToggle(address indexed outbox, bool enabled);
                        function deliverMessageToInbox(
                            uint8 kind,
                            address sender,
                            bytes32 messageDataHash
                        ) external payable returns (uint256);
                        function executeCall(
                            address destAddr,
                            uint256 amount,
                            bytes calldata data
                        ) external returns (bool success, bytes memory returnData);
                        // These are only callable by the admin
                        function setInbox(address inbox, bool enabled) external;
                        function setOutbox(address inbox, bool enabled) external;
                        // View functions
                        function activeOutbox() external view returns (address);
                        function allowedInboxes(address inbox) external view returns (bool);
                        function allowedOutboxes(address outbox) external view returns (bool);
                        function inboxAccs(uint256 index) external view returns (bytes32);
                        function messageCount() external view returns (uint256);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface IMessageProvider {
                        event InboxMessageDelivered(uint256 indexed messageNum, bytes data);
                        event InboxMessageDeliveredFromOrigin(uint256 indexed messageNum);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface IOutbox {
                        event OutboxEntryCreated(
                            uint256 indexed batchNum,
                            uint256 outboxEntryIndex,
                            bytes32 outputRoot,
                            uint256 numInBatch
                        );
                        event OutBoxTransactionExecuted(
                            address indexed destAddr,
                            address indexed l2Sender,
                            uint256 indexed outboxEntryIndex,
                            uint256 transactionIndex
                        );
                        function l2ToL1Sender() external view returns (address);
                        function l2ToL1Block() external view returns (uint256);
                        function l2ToL1EthBlock() external view returns (uint256);
                        function l2ToL1Timestamp() external view returns (uint256);
                        function l2ToL1BatchNum() external view returns (uint256);
                        function l2ToL1OutputId() external view returns (bytes32);
                        function processOutgoingMessages(bytes calldata sendsData, uint256[] calldata sendLengths)
                            external;
                        function outboxEntryExists(uint256 batchNum) external view returns (bool);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface ITokenGateway {
                        /// @notice event deprecated in favor of DepositInitiated and WithdrawalInitiated
                        // event OutboundTransferInitiated(
                        //     address token,
                        //     address indexed _from,
                        //     address indexed _to,
                        //     uint256 indexed _transferId,
                        //     uint256 _amount,
                        //     bytes _data
                        // );
                        /// @notice event deprecated in favor of DepositFinalized and WithdrawalFinalized
                        // event InboundTransferFinalized(
                        //     address token,
                        //     address indexed _from,
                        //     address indexed _to,
                        //     uint256 indexed _transferId,
                        //     uint256 _amount,
                        //     bytes _data
                        // );
                        function outboundTransfer(
                            address _token,
                            address _to,
                            uint256 _amount,
                            uint256 _maxGas,
                            uint256 _gasPriceBid,
                            bytes calldata _data
                        ) external payable returns (bytes memory);
                        function finalizeInboundTransfer(
                            address _token,
                            address _from,
                            address _to,
                            uint256 _amount,
                            bytes calldata _data
                        ) external payable;
                        /**
                         * @notice Calculate the address used when bridging an ERC20 token
                         * @dev the L1 and L2 address oracles may not always be in sync.
                         * For example, a custom token may have been registered but not deploy or the contract self destructed.
                         * @param l1ERC20 address of L1 token
                         * @return L2 address of a bridged ERC20 token
                         */
                        function calculateL2TokenAddress(address l1ERC20) external view returns (address);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "@openzeppelin/contracts/utils/Address.sol";
                    import "arb-bridge-eth/contracts/libraries/BytesLib.sol";
                    import "arb-bridge-eth/contracts/libraries/ProxyUtil.sol";
                    import "arb-bridge-eth/contracts/libraries/AddressAliasHelper.sol";
                    import "../IArbToken.sol";
                    import "../L2ArbitrumMessenger.sol";
                    import "../../libraries/gateway/GatewayMessageHandler.sol";
                    import "../../libraries/gateway/TokenGateway.sol";
                    /**
                     * @title Common interface for gatways on Arbitrum messaging to L1.
                     */
                    abstract contract L2ArbitrumGateway is L2ArbitrumMessenger, TokenGateway {
                        using Address for address;
                        uint256 public exitNum;
                        event DepositFinalized(
                            address indexed l1Token,
                            address indexed _from,
                            address indexed _to,
                            uint256 _amount
                        );
                        event WithdrawalInitiated(
                            address l1Token,
                            address indexed _from,
                            address indexed _to,
                            uint256 indexed _l2ToL1Id,
                            uint256 _exitNum,
                            uint256 _amount
                        );
                        modifier onlyCounterpartGateway() override {
                            require(
                                msg.sender == counterpartGateway ||
                                    AddressAliasHelper.undoL1ToL2Alias(msg.sender) == counterpartGateway,
                                "ONLY_COUNTERPART_GATEWAY"
                            );
                            _;
                        }
                        function postUpgradeInit() external {
                            // it is assumed the L2 Arbitrum Gateway contract is behind a Proxy controlled by a proxy admin
                            // this function can only be called by the proxy admin contract
                            address proxyAdmin = ProxyUtil.getProxyAdmin();
                            require(msg.sender == proxyAdmin, "NOT_FROM_ADMIN");
                            // this has no other logic since the current upgrade doesn't require this logic
                        }
                        function _initialize(address _l1Counterpart, address _router) internal virtual override {
                            TokenGateway._initialize(_l1Counterpart, _router);
                            // L1 gateway must have a router
                            require(_router != address(0), "BAD_ROUTER");
                        }
                        function createOutboundTx(
                            address _from,
                            uint256, /* _tokenAmount */
                            bytes memory _outboundCalldata
                        ) internal virtual returns (uint256) {
                            // We make this function virtual since outboundTransfer logic is the same for many gateways
                            // but sometimes (ie weth) you construct the outgoing message differently.
                            // exitNum incremented after being included in _outboundCalldata
                            exitNum++;
                            return
                                sendTxToL1(
                                    // default to sending no callvalue to the L1
                                    0,
                                    _from,
                                    counterpartGateway,
                                    _outboundCalldata
                                );
                        }
                        function getOutboundCalldata(
                            address _token,
                            address _from,
                            address _to,
                            uint256 _amount,
                            bytes memory _data
                        ) public view override returns (bytes memory outboundCalldata) {
                            outboundCalldata = abi.encodeWithSelector(
                                TokenGateway.finalizeInboundTransfer.selector,
                                _token,
                                _from,
                                _to,
                                _amount,
                                GatewayMessageHandler.encodeFromL2GatewayMsg(exitNum, _data)
                            );
                            return outboundCalldata;
                        }
                        function outboundTransfer(
                            address _l1Token,
                            address _to,
                            uint256 _amount,
                            bytes calldata _data
                        ) public payable virtual returns (bytes memory) {
                            return outboundTransfer(_l1Token, _to, _amount, 0, 0, _data);
                        }
                        /**
                         * @notice Initiates a token withdrawal from Arbitrum to Ethereum
                         * @param _l1Token l1 address of token
                         * @param _to destination address
                         * @param _amount amount of tokens withdrawn
                         * @return res encoded unique identifier for withdrawal
                         */
                        function outboundTransfer(
                            address _l1Token,
                            address _to,
                            uint256 _amount,
                            uint256, /* _maxGas */
                            uint256, /* _gasPriceBid */
                            bytes calldata _data
                        ) public payable virtual override returns (bytes memory res) {
                            // This function is set as public and virtual so that subclasses can override
                            // it and add custom validation for callers (ie only whitelisted users)
                            // the function is marked as payable to conform to the inheritance setup
                            // this particular code path shouldn't have a msg.value > 0
                            // TODO: remove this invariant for execution markets
                            require(msg.value == 0, "NO_VALUE");
                            address _from;
                            bytes memory _extraData;
                            {
                                if (isRouter(msg.sender)) {
                                    (_from, _extraData) = GatewayMessageHandler.parseFromRouterToGateway(_data);
                                } else {
                                    _from = msg.sender;
                                    _extraData = _data;
                                }
                            }
                            // the inboundEscrowAndCall functionality has been disabled, so no data is allowed
                            require(_extraData.length == 0, "EXTRA_DATA_DISABLED");
                            uint256 id;
                            {
                                address l2Token = calculateL2TokenAddress(_l1Token);
                                require(l2Token.isContract(), "TOKEN_NOT_DEPLOYED");
                                require(IArbToken(l2Token).l1Address() == _l1Token, "NOT_EXPECTED_L1_TOKEN");
                                _amount = outboundEscrowTransfer(l2Token, _from, _amount);
                                id = triggerWithdrawal(_l1Token, _from, _to, _amount, _extraData);
                            }
                            return abi.encode(id);
                        }
                        function triggerWithdrawal(
                            address _l1Token,
                            address _from,
                            address _to,
                            uint256 _amount,
                            bytes memory _data
                        ) internal returns (uint256) {
                            // exit number used for tradeable exits
                            uint256 currExitNum = exitNum;
                            // unique id used to identify the L2 to L1 tx
                            uint256 id = createOutboundTx(
                                _from,
                                _amount,
                                getOutboundCalldata(_l1Token, _from, _to, _amount, _data)
                            );
                            emit WithdrawalInitiated(_l1Token, _from, _to, id, currExitNum, _amount);
                            return id;
                        }
                        function outboundEscrowTransfer(
                            address _l2Token,
                            address _from,
                            uint256 _amount
                        ) internal virtual returns (uint256 amountBurnt) {
                            // this method is virtual since different subclasses can handle escrow differently
                            // user funds are escrowed on the gateway using this function
                            // burns L2 tokens in order to release escrowed L1 tokens
                            IArbToken(_l2Token).bridgeBurn(_from, _amount);
                            // by default we assume that the amount we send to bridgeBurn is the amount burnt
                            // this might not be the case for every token
                            return _amount;
                        }
                        function inboundEscrowTransfer(
                            address _l2Address,
                            address _dest,
                            uint256 _amount
                        ) internal virtual {
                            // this method is virtual since different subclasses can handle escrow differently
                            IArbToken(_l2Address).bridgeMint(_dest, _amount);
                        }
                        /**
                         * @notice Mint on L2 upon L1 deposit.
                         * If token not yet deployed and symbol/name/decimal data is included, deploys StandardArbERC20
                         * @dev Callable only by the L1ERC20Gateway.outboundTransfer method. For initial deployments of a token the L1 L1ERC20Gateway
                         * is expected to include the deployData. If not a L1 withdrawal is automatically triggered for the user
                         * @param _token L1 address of ERC20
                         * @param _from account that initiated the deposit in the L1
                         * @param _to account to be credited with the tokens in the L2 (can be the user's L2 account or a contract)
                         * @param _amount token amount to be minted to the user
                         * @param _data encoded symbol/name/decimal data for deploy, in addition to any additional callhook data
                         */
                        function finalizeInboundTransfer(
                            address _token,
                            address _from,
                            address _to,
                            uint256 _amount,
                            bytes calldata _data
                        ) external payable override onlyCounterpartGateway {
                            (bytes memory gatewayData, bytes memory callHookData) = GatewayMessageHandler
                                .parseFromL1GatewayMsg(_data);
                            if (callHookData.length != 0) {
                                // callHookData should always be 0 since inboundEscrowAndCall is disabled
                                callHookData = bytes("");
                            }
                            address expectedAddress = calculateL2TokenAddress(_token);
                            if (!expectedAddress.isContract()) {
                                bool shouldHalt = handleNoContract(
                                    _token,
                                    expectedAddress,
                                    _from,
                                    _to,
                                    _amount,
                                    gatewayData
                                );
                                if (shouldHalt) return;
                            }
                            // ignores gatewayData if token already deployed
                            {
                                // validate if L1 address supplied matches that of the expected L2 address
                                (bool success, bytes memory _l1AddressData) = expectedAddress.staticcall(
                                    abi.encodeWithSelector(IArbToken.l1Address.selector)
                                );
                                bool shouldWithdraw;
                                if (!success || _l1AddressData.length < 32) {
                                    shouldWithdraw = true;
                                } else {
                                    // we do this in the else branch since we want to avoid reverts
                                    // and `toAddress` reverts if _l1AddressData has a short length
                                    // `_l1AddressData` should be 12 bytes of padding then 20 bytes for the address
                                    address expectedL1Address = BytesLib.toAddress(_l1AddressData, 12);
                                    if (expectedL1Address != _token) {
                                        shouldWithdraw = true;
                                    }
                                }
                                if (shouldWithdraw) {
                                    // we don't need the return value from triggerWithdrawal since this is forcing
                                    // a withdrawal back to the L1 instead of composing with a L2 dapp
                                    triggerWithdrawal(_token, address(this), _from, _amount, "");
                                    return;
                                }
                            }
                            inboundEscrowTransfer(expectedAddress, _to, _amount);
                            emit DepositFinalized(_token, _from, _to, _amount);
                            return;
                        }
                        // returns if function should halt after
                        function handleNoContract(
                            address _l1Token,
                            address expectedL2Address,
                            address _from,
                            address _to,
                            uint256 _amount,
                            bytes memory gatewayData
                        ) internal virtual returns (bool shouldHalt);
                    }
                    // SPDX-License-Identifier: MIT
                    /*
                     * @title Solidity Bytes Arrays Utils
                     * @author Gonçalo Sá <goncalo.sa@consensys.net>
                     *
                     * @dev Bytes tightly packed arrays utility library for ethereum contracts written in Solidity.
                     *      The library lets you concatenate, slice and type cast bytes arrays both in memory and storage.
                     */
                    pragma solidity ^0.6.11;
                    /* solhint-disable no-inline-assembly */
                    library BytesLib {
                        function toAddress(bytes memory _bytes, uint256 _start) internal pure returns (address) {
                            require(_bytes.length >= (_start + 20), "Read out of bounds");
                            address tempAddress;
                            assembly {
                                tempAddress := div(mload(add(add(_bytes, 0x20), _start)), 0x1000000000000000000000000)
                            }
                            return tempAddress;
                        }
                        function toUint8(bytes memory _bytes, uint256 _start) internal pure returns (uint8) {
                            require(_bytes.length >= (_start + 1), "Read out of bounds");
                            uint8 tempUint;
                            assembly {
                                tempUint := mload(add(add(_bytes, 0x1), _start))
                            }
                            return tempUint;
                        }
                        function toUint(bytes memory _bytes, uint256 _start) internal pure returns (uint256) {
                            require(_bytes.length >= (_start + 32), "Read out of bounds");
                            uint256 tempUint;
                            assembly {
                                tempUint := mload(add(add(_bytes, 0x20), _start))
                            }
                            return tempUint;
                        }
                        function toBytes32(bytes memory _bytes, uint256 _start) internal pure returns (bytes32) {
                            require(_bytes.length >= (_start + 32), "Read out of bounds");
                            bytes32 tempBytes32;
                            assembly {
                                tempBytes32 := mload(add(add(_bytes, 0x20), _start))
                            }
                            return tempBytes32;
                        }
                    }
                    /* solhint-enable no-inline-assembly */
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2019-2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    library AddressAliasHelper {
                        /// @notice Utility function that converts the msg.sender viewed in the L2 to the
                        /// address in the L1 that submitted a tx to the inbox
                        /// @param l2address L2 address as viewed in msg.sender
                        /// @return l1Address the address in the L1 that triggered the tx to L2
                        function undoL1ToL2Alias(address l2address) internal pure returns (address l1Address) {
                            uint160 offset = uint160(0x1111000000000000000000000000000000001111);
                            l1Address = address(uint160(l2address) - offset);
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    /**
                     * @title Minimum expected interface for L2 token that interacts with the L2 token bridge (this is the interface necessary
                     * for a custom token that interacts with the bridge, see TestArbCustomToken.sol for an example implementation).
                     */
                    pragma solidity ^0.6.11;
                    interface IArbToken {
                        /**
                         * @notice should increase token supply by amount, and should (probably) only be callable by the L1 bridge.
                         */
                        function bridgeMint(address account, uint256 amount) external;
                        /**
                         * @notice should decrease token supply by amount, and should (probably) only be callable by the L1 bridge.
                         */
                        function bridgeBurn(address account, uint256 amount) external;
                        /**
                         * @return address of layer 1 token
                         */
                        function l1Address() external view returns (address);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "arbos-contracts/arbos/builtin/ArbSys.sol";
                    /// @notice L2 utility contract to assist with L1 <=> L2 interactions
                    /// @dev this is an abstract contract instead of library so the functions can be easily overriden when testing
                    abstract contract L2ArbitrumMessenger {
                        address internal constant ARB_SYS_ADDRESS = address(100);
                        event TxToL1(address indexed _from, address indexed _to, uint256 indexed _id, bytes _data);
                        function sendTxToL1(
                            uint256 _l1CallValue,
                            address _from,
                            address _to,
                            bytes memory _data
                        ) internal virtual returns (uint256) {
                            uint256 _id = ArbSys(ARB_SYS_ADDRESS).sendTxToL1{ value: _l1CallValue }(_to, _data);
                            emit TxToL1(_from, _to, _id, _data);
                            return _id;
                        }
                    }
                    pragma solidity >=0.4.21 <0.7.0;
                    /**
                    * @title Precompiled contract that exists in every Arbitrum chain at address(100), 0x0000000000000000000000000000000000000064. Exposes a variety of system-level functionality.
                     */
                    interface ArbSys {
                        /**
                        * @notice Get internal version number identifying an ArbOS build
                        * @return version number as int
                         */
                        function arbOSVersion() external pure returns (uint);
                        function arbChainID() external view returns(uint);
                        /**
                        * @notice Get Arbitrum block number (distinct from L1 block number; Arbitrum genesis block has block number 0)
                        * @return block number as int
                         */ 
                        function arbBlockNumber() external view returns (uint);
                        /** 
                        * @notice Send given amount of Eth to dest from sender.
                        * This is a convenience function, which is equivalent to calling sendTxToL1 with empty calldataForL1.
                        * @param destination recipient address on L1
                        * @return unique identifier for this L2-to-L1 transaction.
                        */
                        function withdrawEth(address destination) external payable returns(uint);
                        /** 
                        * @notice Send a transaction to L1
                        * @param destination recipient address on L1 
                        * @param calldataForL1 (optional) calldata for L1 contract call
                        * @return a unique identifier for this L2-to-L1 transaction.
                        */
                        function sendTxToL1(address destination, bytes calldata calldataForL1) external payable returns(uint);
                        /** 
                        * @notice get the number of transactions issued by the given external account or the account sequence number of the given contract
                        * @param account target account
                        * @return the number of transactions issued by the given external account or the account sequence number of the given contract
                        */
                        function getTransactionCount(address account) external view returns(uint256);
                        /**  
                        * @notice get the value of target L2 storage slot 
                        * This function is only callable from address 0 to prevent contracts from being able to call it
                        * @param account target account
                        * @param index target index of storage slot 
                        * @return stotage value for the given account at the given index
                        */
                        function getStorageAt(address account, uint256 index) external view returns (uint256);
                        /**
                        * @notice check if current call is coming from l1
                        * @return true if the caller of this was called directly from L1
                        */
                        function isTopLevelCall() external view returns (bool);
                        event L2ToL1Transaction(address caller, address indexed destination, uint indexed uniqueId,
                                                uint indexed batchNumber, uint indexInBatch,
                                                uint arbBlockNum, uint ethBlockNum, uint timestamp,
                                                uint callvalue, bytes data);
                    }
                    

                    File 8 of 9: FiatTokenV2_1
                    // File: @openzeppelin/contracts/math/SafeMath.sol
                    
                    // SPDX-License-Identifier: MIT
                    
                    pragma solidity ^0.6.0;
                    
                    /**
                     * @dev Wrappers over Solidity's arithmetic operations with added overflow
                     * checks.
                     *
                     * Arithmetic operations in Solidity wrap on overflow. This can easily result
                     * in bugs, because programmers usually assume that an overflow raises an
                     * error, which is the standard behavior in high level programming languages.
                     * `SafeMath` restores this intuition by reverting the transaction when an
                     * operation overflows.
                     *
                     * Using this library instead of the unchecked operations eliminates an entire
                     * class of bugs, so it's recommended to use it always.
                     */
                    library SafeMath {
                        /**
                         * @dev Returns the addition of two unsigned integers, reverting on
                         * overflow.
                         *
                         * Counterpart to Solidity's `+` operator.
                         *
                         * Requirements:
                         *
                         * - Addition cannot overflow.
                         */
                        function add(uint256 a, uint256 b) internal pure returns (uint256) {
                            uint256 c = a + b;
                            require(c >= a, "SafeMath: addition overflow");
                    
                            return c;
                        }
                    
                        /**
                         * @dev Returns the subtraction of two unsigned integers, reverting on
                         * overflow (when the result is negative).
                         *
                         * Counterpart to Solidity's `-` operator.
                         *
                         * Requirements:
                         *
                         * - Subtraction cannot overflow.
                         */
                        function sub(uint256 a, uint256 b) internal pure returns (uint256) {
                            return sub(a, b, "SafeMath: subtraction overflow");
                        }
                    
                        /**
                         * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
                         * overflow (when the result is negative).
                         *
                         * Counterpart to Solidity's `-` operator.
                         *
                         * Requirements:
                         *
                         * - Subtraction cannot overflow.
                         */
                        function sub(
                            uint256 a,
                            uint256 b,
                            string memory errorMessage
                        ) internal pure returns (uint256) {
                            require(b <= a, errorMessage);
                            uint256 c = a - b;
                    
                            return c;
                        }
                    
                        /**
                         * @dev Returns the multiplication of two unsigned integers, reverting on
                         * overflow.
                         *
                         * Counterpart to Solidity's `*` operator.
                         *
                         * Requirements:
                         *
                         * - Multiplication cannot overflow.
                         */
                        function mul(uint256 a, uint256 b) internal pure returns (uint256) {
                            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
                            // benefit is lost if 'b' is also tested.
                            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
                            if (a == 0) {
                                return 0;
                            }
                    
                            uint256 c = a * b;
                            require(c / a == b, "SafeMath: multiplication overflow");
                    
                            return c;
                        }
                    
                        /**
                         * @dev Returns the integer division of two unsigned integers. Reverts on
                         * division by zero. The result is rounded towards zero.
                         *
                         * Counterpart to Solidity's `/` operator. Note: this function uses a
                         * `revert` opcode (which leaves remaining gas untouched) while Solidity
                         * uses an invalid opcode to revert (consuming all remaining gas).
                         *
                         * Requirements:
                         *
                         * - The divisor cannot be zero.
                         */
                        function div(uint256 a, uint256 b) internal pure returns (uint256) {
                            return div(a, b, "SafeMath: division by zero");
                        }
                    
                        /**
                         * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
                         * division by zero. The result is rounded towards zero.
                         *
                         * Counterpart to Solidity's `/` operator. Note: this function uses a
                         * `revert` opcode (which leaves remaining gas untouched) while Solidity
                         * uses an invalid opcode to revert (consuming all remaining gas).
                         *
                         * Requirements:
                         *
                         * - The divisor cannot be zero.
                         */
                        function div(
                            uint256 a,
                            uint256 b,
                            string memory errorMessage
                        ) internal pure returns (uint256) {
                            require(b > 0, errorMessage);
                            uint256 c = a / b;
                            // assert(a == b * c + a % b); // There is no case in which this doesn't hold
                    
                            return c;
                        }
                    
                        /**
                         * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                         * Reverts when dividing by zero.
                         *
                         * Counterpart to Solidity's `%` operator. This function uses a `revert`
                         * opcode (which leaves remaining gas untouched) while Solidity uses an
                         * invalid opcode to revert (consuming all remaining gas).
                         *
                         * Requirements:
                         *
                         * - The divisor cannot be zero.
                         */
                        function mod(uint256 a, uint256 b) internal pure returns (uint256) {
                            return mod(a, b, "SafeMath: modulo by zero");
                        }
                    
                        /**
                         * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                         * Reverts with custom message when dividing by zero.
                         *
                         * Counterpart to Solidity's `%` operator. This function uses a `revert`
                         * opcode (which leaves remaining gas untouched) while Solidity uses an
                         * invalid opcode to revert (consuming all remaining gas).
                         *
                         * Requirements:
                         *
                         * - The divisor cannot be zero.
                         */
                        function mod(
                            uint256 a,
                            uint256 b,
                            string memory errorMessage
                        ) internal pure returns (uint256) {
                            require(b != 0, errorMessage);
                            return a % b;
                        }
                    }
                    
                    // File: @openzeppelin/contracts/token/ERC20/IERC20.sol
                    
                    pragma solidity ^0.6.0;
                    
                    /**
                     * @dev Interface of the ERC20 standard as defined in the EIP.
                     */
                    interface IERC20 {
                        /**
                         * @dev Returns the amount of tokens in existence.
                         */
                        function totalSupply() external view returns (uint256);
                    
                        /**
                         * @dev Returns the amount of tokens owned by `account`.
                         */
                        function balanceOf(address account) external view returns (uint256);
                    
                        /**
                         * @dev Moves `amount` tokens from the caller's account to `recipient`.
                         *
                         * Returns a boolean value indicating whether the operation succeeded.
                         *
                         * Emits a {Transfer} event.
                         */
                        function transfer(address recipient, uint256 amount)
                            external
                            returns (bool);
                    
                        /**
                         * @dev Returns the remaining number of tokens that `spender` will be
                         * allowed to spend on behalf of `owner` through {transferFrom}. This is
                         * zero by default.
                         *
                         * This value changes when {approve} or {transferFrom} are called.
                         */
                        function allowance(address owner, address spender)
                            external
                            view
                            returns (uint256);
                    
                        /**
                         * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
                         *
                         * Returns a boolean value indicating whether the operation succeeded.
                         *
                         * IMPORTANT: Beware that changing an allowance with this method brings the risk
                         * that someone may use both the old and the new allowance by unfortunate
                         * transaction ordering. One possible solution to mitigate this race
                         * condition is to first reduce the spender's allowance to 0 and set the
                         * desired value afterwards:
                         * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
                         *
                         * Emits an {Approval} event.
                         */
                        function approve(address spender, uint256 amount) external returns (bool);
                    
                        /**
                         * @dev Moves `amount` tokens from `sender` to `recipient` using the
                         * allowance mechanism. `amount` is then deducted from the caller's
                         * allowance.
                         *
                         * Returns a boolean value indicating whether the operation succeeded.
                         *
                         * Emits a {Transfer} event.
                         */
                        function transferFrom(
                            address sender,
                            address recipient,
                            uint256 amount
                        ) external returns (bool);
                    
                        /**
                         * @dev Emitted when `value` tokens are moved from one account (`from`) to
                         * another (`to`).
                         *
                         * Note that `value` may be zero.
                         */
                        event Transfer(address indexed from, address indexed to, uint256 value);
                    
                        /**
                         * @dev Emitted when the allowance of a `spender` for an `owner` is set by
                         * a call to {approve}. `value` is the new allowance.
                         */
                        event Approval(
                            address indexed owner,
                            address indexed spender,
                            uint256 value
                        );
                    }
                    
                    // File: contracts/v1/AbstractFiatTokenV1.sol
                    
                    /**
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    abstract contract AbstractFiatTokenV1 is IERC20 {
                        function _approve(
                            address owner,
                            address spender,
                            uint256 value
                        ) internal virtual;
                    
                        function _transfer(
                            address from,
                            address to,
                            uint256 value
                        ) internal virtual;
                    }
                    
                    // File: contracts/v1/Ownable.sol
                    
                    /**
                     * Copyright (c) 2018 zOS Global Limited.
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    pragma solidity 0.6.12;
                    
                    /**
                     * @notice The Ownable contract has an owner address, and provides basic
                     * authorization control functions
                     * @dev Forked from https://github.com/OpenZeppelin/openzeppelin-labs/blob/3887ab77b8adafba4a26ace002f3a684c1a3388b/upgradeability_ownership/contracts/ownership/Ownable.sol
                     * Modifications:
                     * 1. Consolidate OwnableStorage into this contract (7/13/18)
                     * 2. Reformat, conform to Solidity 0.6 syntax, and add error messages (5/13/20)
                     * 3. Make public functions external (5/27/20)
                     */
                    contract Ownable {
                        // Owner of the contract
                        address private _owner;
                    
                        /**
                         * @dev Event to show ownership has been transferred
                         * @param previousOwner representing the address of the previous owner
                         * @param newOwner representing the address of the new owner
                         */
                        event OwnershipTransferred(address previousOwner, address newOwner);
                    
                        /**
                         * @dev The constructor sets the original owner of the contract to the sender account.
                         */
                        constructor() public {
                            setOwner(msg.sender);
                        }
                    
                        /**
                         * @dev Tells the address of the owner
                         * @return the address of the owner
                         */
                        function owner() external view returns (address) {
                            return _owner;
                        }
                    
                        /**
                         * @dev Sets a new owner address
                         */
                        function setOwner(address newOwner) internal {
                            _owner = newOwner;
                        }
                    
                        /**
                         * @dev Throws if called by any account other than the owner.
                         */
                        modifier onlyOwner() {
                            require(msg.sender == _owner, "Ownable: caller is not the owner");
                            _;
                        }
                    
                        /**
                         * @dev Allows the current owner to transfer control of the contract to a newOwner.
                         * @param newOwner The address to transfer ownership to.
                         */
                        function transferOwnership(address newOwner) external onlyOwner {
                            require(
                                newOwner != address(0),
                                "Ownable: new owner is the zero address"
                            );
                            emit OwnershipTransferred(_owner, newOwner);
                            setOwner(newOwner);
                        }
                    }
                    
                    // File: contracts/v1/Pausable.sol
                    
                    /**
                     * Copyright (c) 2016 Smart Contract Solutions, Inc.
                     * Copyright (c) 2018-2020 CENTRE SECZ0
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    /**
                     * @notice Base contract which allows children to implement an emergency stop
                     * mechanism
                     * @dev Forked from https://github.com/OpenZeppelin/openzeppelin-contracts/blob/feb665136c0dae9912e08397c1a21c4af3651ef3/contracts/lifecycle/Pausable.sol
                     * Modifications:
                     * 1. Added pauser role, switched pause/unpause to be onlyPauser (6/14/2018)
                     * 2. Removed whenNotPause/whenPaused from pause/unpause (6/14/2018)
                     * 3. Removed whenPaused (6/14/2018)
                     * 4. Switches ownable library to use ZeppelinOS (7/12/18)
                     * 5. Remove constructor (7/13/18)
                     * 6. Reformat, conform to Solidity 0.6 syntax and add error messages (5/13/20)
                     * 7. Make public functions external (5/27/20)
                     */
                    contract Pausable is Ownable {
                        event Pause();
                        event Unpause();
                        event PauserChanged(address indexed newAddress);
                    
                        address public pauser;
                        bool public paused = false;
                    
                        /**
                         * @dev Modifier to make a function callable only when the contract is not paused.
                         */
                        modifier whenNotPaused() {
                            require(!paused, "Pausable: paused");
                            _;
                        }
                    
                        /**
                         * @dev throws if called by any account other than the pauser
                         */
                        modifier onlyPauser() {
                            require(msg.sender == pauser, "Pausable: caller is not the pauser");
                            _;
                        }
                    
                        /**
                         * @dev called by the owner to pause, triggers stopped state
                         */
                        function pause() external onlyPauser {
                            paused = true;
                            emit Pause();
                        }
                    
                        /**
                         * @dev called by the owner to unpause, returns to normal state
                         */
                        function unpause() external onlyPauser {
                            paused = false;
                            emit Unpause();
                        }
                    
                        /**
                         * @dev update the pauser role
                         */
                        function updatePauser(address _newPauser) external onlyOwner {
                            require(
                                _newPauser != address(0),
                                "Pausable: new pauser is the zero address"
                            );
                            pauser = _newPauser;
                            emit PauserChanged(pauser);
                        }
                    }
                    
                    // File: contracts/v1/Blacklistable.sol
                    
                    /**
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    /**
                     * @title Blacklistable Token
                     * @dev Allows accounts to be blacklisted by a "blacklister" role
                     */
                    contract Blacklistable is Ownable {
                        address public blacklister;
                        mapping(address => bool) internal blacklisted;
                    
                        event Blacklisted(address indexed _account);
                        event UnBlacklisted(address indexed _account);
                        event BlacklisterChanged(address indexed newBlacklister);
                    
                        /**
                         * @dev Throws if called by any account other than the blacklister
                         */
                        modifier onlyBlacklister() {
                            require(
                                msg.sender == blacklister,
                                "Blacklistable: caller is not the blacklister"
                            );
                            _;
                        }
                    
                        /**
                         * @dev Throws if argument account is blacklisted
                         * @param _account The address to check
                         */
                        modifier notBlacklisted(address _account) {
                            require(
                                !blacklisted[_account],
                                "Blacklistable: account is blacklisted"
                            );
                            _;
                        }
                    
                        /**
                         * @dev Checks if account is blacklisted
                         * @param _account The address to check
                         */
                        function isBlacklisted(address _account) external view returns (bool) {
                            return blacklisted[_account];
                        }
                    
                        /**
                         * @dev Adds account to blacklist
                         * @param _account The address to blacklist
                         */
                        function blacklist(address _account) external onlyBlacklister {
                            blacklisted[_account] = true;
                            emit Blacklisted(_account);
                        }
                    
                        /**
                         * @dev Removes account from blacklist
                         * @param _account The address to remove from the blacklist
                         */
                        function unBlacklist(address _account) external onlyBlacklister {
                            blacklisted[_account] = false;
                            emit UnBlacklisted(_account);
                        }
                    
                        function updateBlacklister(address _newBlacklister) external onlyOwner {
                            require(
                                _newBlacklister != address(0),
                                "Blacklistable: new blacklister is the zero address"
                            );
                            blacklister = _newBlacklister;
                            emit BlacklisterChanged(blacklister);
                        }
                    }
                    
                    // File: contracts/v1/FiatTokenV1.sol
                    
                    /**
                     *
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    /**
                     * @title FiatToken
                     * @dev ERC20 Token backed by fiat reserves
                     */
                    contract FiatTokenV1 is AbstractFiatTokenV1, Ownable, Pausable, Blacklistable {
                        using SafeMath for uint256;
                    
                        string public name;
                        string public symbol;
                        uint8 public decimals;
                        string public currency;
                        address public masterMinter;
                        bool internal initialized;
                    
                        mapping(address => uint256) internal balances;
                        mapping(address => mapping(address => uint256)) internal allowed;
                        uint256 internal totalSupply_ = 0;
                        mapping(address => bool) internal minters;
                        mapping(address => uint256) internal minterAllowed;
                    
                        event Mint(address indexed minter, address indexed to, uint256 amount);
                        event Burn(address indexed burner, uint256 amount);
                        event MinterConfigured(address indexed minter, uint256 minterAllowedAmount);
                        event MinterRemoved(address indexed oldMinter);
                        event MasterMinterChanged(address indexed newMasterMinter);
                    
                        function initialize(
                            string memory tokenName,
                            string memory tokenSymbol,
                            string memory tokenCurrency,
                            uint8 tokenDecimals,
                            address newMasterMinter,
                            address newPauser,
                            address newBlacklister,
                            address newOwner
                        ) public {
                            require(!initialized, "FiatToken: contract is already initialized");
                            require(
                                newMasterMinter != address(0),
                                "FiatToken: new masterMinter is the zero address"
                            );
                            require(
                                newPauser != address(0),
                                "FiatToken: new pauser is the zero address"
                            );
                            require(
                                newBlacklister != address(0),
                                "FiatToken: new blacklister is the zero address"
                            );
                            require(
                                newOwner != address(0),
                                "FiatToken: new owner is the zero address"
                            );
                    
                            name = tokenName;
                            symbol = tokenSymbol;
                            currency = tokenCurrency;
                            decimals = tokenDecimals;
                            masterMinter = newMasterMinter;
                            pauser = newPauser;
                            blacklister = newBlacklister;
                            setOwner(newOwner);
                            initialized = true;
                        }
                    
                        /**
                         * @dev Throws if called by any account other than a minter
                         */
                        modifier onlyMinters() {
                            require(minters[msg.sender], "FiatToken: caller is not a minter");
                            _;
                        }
                    
                        /**
                         * @dev Function to mint tokens
                         * @param _to The address that will receive the minted tokens.
                         * @param _amount The amount of tokens to mint. Must be less than or equal
                         * to the minterAllowance of the caller.
                         * @return A boolean that indicates if the operation was successful.
                         */
                        function mint(address _to, uint256 _amount)
                            external
                            whenNotPaused
                            onlyMinters
                            notBlacklisted(msg.sender)
                            notBlacklisted(_to)
                            returns (bool)
                        {
                            require(_to != address(0), "FiatToken: mint to the zero address");
                            require(_amount > 0, "FiatToken: mint amount not greater than 0");
                    
                            uint256 mintingAllowedAmount = minterAllowed[msg.sender];
                            require(
                                _amount <= mintingAllowedAmount,
                                "FiatToken: mint amount exceeds minterAllowance"
                            );
                    
                            totalSupply_ = totalSupply_.add(_amount);
                            balances[_to] = balances[_to].add(_amount);
                            minterAllowed[msg.sender] = mintingAllowedAmount.sub(_amount);
                            emit Mint(msg.sender, _to, _amount);
                            emit Transfer(address(0), _to, _amount);
                            return true;
                        }
                    
                        /**
                         * @dev Throws if called by any account other than the masterMinter
                         */
                        modifier onlyMasterMinter() {
                            require(
                                msg.sender == masterMinter,
                                "FiatToken: caller is not the masterMinter"
                            );
                            _;
                        }
                    
                        /**
                         * @dev Get minter allowance for an account
                         * @param minter The address of the minter
                         */
                        function minterAllowance(address minter) external view returns (uint256) {
                            return minterAllowed[minter];
                        }
                    
                        /**
                         * @dev Checks if account is a minter
                         * @param account The address to check
                         */
                        function isMinter(address account) external view returns (bool) {
                            return minters[account];
                        }
                    
                        /**
                         * @notice Amount of remaining tokens spender is allowed to transfer on
                         * behalf of the token owner
                         * @param owner     Token owner's address
                         * @param spender   Spender's address
                         * @return Allowance amount
                         */
                        function allowance(address owner, address spender)
                            external
                            override
                            view
                            returns (uint256)
                        {
                            return allowed[owner][spender];
                        }
                    
                        /**
                         * @dev Get totalSupply of token
                         */
                        function totalSupply() external override view returns (uint256) {
                            return totalSupply_;
                        }
                    
                        /**
                         * @dev Get token balance of an account
                         * @param account address The account
                         */
                        function balanceOf(address account)
                            external
                            override
                            view
                            returns (uint256)
                        {
                            return balances[account];
                        }
                    
                        /**
                         * @notice Set spender's allowance over the caller's tokens to be a given
                         * value.
                         * @param spender   Spender's address
                         * @param value     Allowance amount
                         * @return True if successful
                         */
                        function approve(address spender, uint256 value)
                            external
                            override
                            whenNotPaused
                            notBlacklisted(msg.sender)
                            notBlacklisted(spender)
                            returns (bool)
                        {
                            _approve(msg.sender, spender, value);
                            return true;
                        }
                    
                        /**
                         * @dev Internal function to set allowance
                         * @param owner     Token owner's address
                         * @param spender   Spender's address
                         * @param value     Allowance amount
                         */
                        function _approve(
                            address owner,
                            address spender,
                            uint256 value
                        ) internal override {
                            require(owner != address(0), "ERC20: approve from the zero address");
                            require(spender != address(0), "ERC20: approve to the zero address");
                            allowed[owner][spender] = value;
                            emit Approval(owner, spender, value);
                        }
                    
                        /**
                         * @notice Transfer tokens by spending allowance
                         * @param from  Payer's address
                         * @param to    Payee's address
                         * @param value Transfer amount
                         * @return True if successful
                         */
                        function transferFrom(
                            address from,
                            address to,
                            uint256 value
                        )
                            external
                            override
                            whenNotPaused
                            notBlacklisted(msg.sender)
                            notBlacklisted(from)
                            notBlacklisted(to)
                            returns (bool)
                        {
                            require(
                                value <= allowed[from][msg.sender],
                                "ERC20: transfer amount exceeds allowance"
                            );
                            _transfer(from, to, value);
                            allowed[from][msg.sender] = allowed[from][msg.sender].sub(value);
                            return true;
                        }
                    
                        /**
                         * @notice Transfer tokens from the caller
                         * @param to    Payee's address
                         * @param value Transfer amount
                         * @return True if successful
                         */
                        function transfer(address to, uint256 value)
                            external
                            override
                            whenNotPaused
                            notBlacklisted(msg.sender)
                            notBlacklisted(to)
                            returns (bool)
                        {
                            _transfer(msg.sender, to, value);
                            return true;
                        }
                    
                        /**
                         * @notice Internal function to process transfers
                         * @param from  Payer's address
                         * @param to    Payee's address
                         * @param value Transfer amount
                         */
                        function _transfer(
                            address from,
                            address to,
                            uint256 value
                        ) internal override {
                            require(from != address(0), "ERC20: transfer from the zero address");
                            require(to != address(0), "ERC20: transfer to the zero address");
                            require(
                                value <= balances[from],
                                "ERC20: transfer amount exceeds balance"
                            );
                    
                            balances[from] = balances[from].sub(value);
                            balances[to] = balances[to].add(value);
                            emit Transfer(from, to, value);
                        }
                    
                        /**
                         * @dev Function to add/update a new minter
                         * @param minter The address of the minter
                         * @param minterAllowedAmount The minting amount allowed for the minter
                         * @return True if the operation was successful.
                         */
                        function configureMinter(address minter, uint256 minterAllowedAmount)
                            external
                            whenNotPaused
                            onlyMasterMinter
                            returns (bool)
                        {
                            minters[minter] = true;
                            minterAllowed[minter] = minterAllowedAmount;
                            emit MinterConfigured(minter, minterAllowedAmount);
                            return true;
                        }
                    
                        /**
                         * @dev Function to remove a minter
                         * @param minter The address of the minter to remove
                         * @return True if the operation was successful.
                         */
                        function removeMinter(address minter)
                            external
                            onlyMasterMinter
                            returns (bool)
                        {
                            minters[minter] = false;
                            minterAllowed[minter] = 0;
                            emit MinterRemoved(minter);
                            return true;
                        }
                    
                        /**
                         * @dev allows a minter to burn some of its own tokens
                         * Validates that caller is a minter and that sender is not blacklisted
                         * amount is less than or equal to the minter's account balance
                         * @param _amount uint256 the amount of tokens to be burned
                         */
                        function burn(uint256 _amount)
                            external
                            whenNotPaused
                            onlyMinters
                            notBlacklisted(msg.sender)
                        {
                            uint256 balance = balances[msg.sender];
                            require(_amount > 0, "FiatToken: burn amount not greater than 0");
                            require(balance >= _amount, "FiatToken: burn amount exceeds balance");
                    
                            totalSupply_ = totalSupply_.sub(_amount);
                            balances[msg.sender] = balance.sub(_amount);
                            emit Burn(msg.sender, _amount);
                            emit Transfer(msg.sender, address(0), _amount);
                        }
                    
                        function updateMasterMinter(address _newMasterMinter) external onlyOwner {
                            require(
                                _newMasterMinter != address(0),
                                "FiatToken: new masterMinter is the zero address"
                            );
                            masterMinter = _newMasterMinter;
                            emit MasterMinterChanged(masterMinter);
                        }
                    }
                    
                    // File: @openzeppelin/contracts/utils/Address.sol
                    
                    pragma solidity ^0.6.2;
                    
                    /**
                     * @dev Collection of functions related to the address type
                     */
                    library Address {
                        /**
                         * @dev Returns true if `account` is a contract.
                         *
                         * [IMPORTANT]
                         * ====
                         * It is unsafe to assume that an address for which this function returns
                         * false is an externally-owned account (EOA) and not a contract.
                         *
                         * Among others, `isContract` will return false for the following
                         * types of addresses:
                         *
                         *  - an externally-owned account
                         *  - a contract in construction
                         *  - an address where a contract will be created
                         *  - an address where a contract lived, but was destroyed
                         * ====
                         */
                        function isContract(address account) internal view returns (bool) {
                            // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
                            // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
                            // for accounts without code, i.e. `keccak256('')`
                            bytes32 codehash;
                    
                                bytes32 accountHash
                             = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                codehash := extcodehash(account)
                            }
                            return (codehash != accountHash && codehash != 0x0);
                        }
                    
                        /**
                         * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
                         * `recipient`, forwarding all available gas and reverting on errors.
                         *
                         * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
                         * of certain opcodes, possibly making contracts go over the 2300 gas limit
                         * imposed by `transfer`, making them unable to receive funds via
                         * `transfer`. {sendValue} removes this limitation.
                         *
                         * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
                         *
                         * IMPORTANT: because control is transferred to `recipient`, care must be
                         * taken to not create reentrancy vulnerabilities. Consider using
                         * {ReentrancyGuard} or the
                         * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
                         */
                        function sendValue(address payable recipient, uint256 amount) internal {
                            require(
                                address(this).balance >= amount,
                                "Address: insufficient balance"
                            );
                    
                            // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
                            (bool success, ) = recipient.call{ value: amount }("");
                            require(
                                success,
                                "Address: unable to send value, recipient may have reverted"
                            );
                        }
                    
                        /**
                         * @dev Performs a Solidity function call using a low level `call`. A
                         * plain`call` is an unsafe replacement for a function call: use this
                         * function instead.
                         *
                         * If `target` reverts with a revert reason, it is bubbled up by this
                         * function (like regular Solidity function calls).
                         *
                         * Returns the raw returned data. To convert to the expected return value,
                         * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
                         *
                         * Requirements:
                         *
                         * - `target` must be a contract.
                         * - calling `target` with `data` must not revert.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data)
                            internal
                            returns (bytes memory)
                        {
                            return functionCall(target, data, "Address: low-level call failed");
                        }
                    
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
                         * `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(
                            address target,
                            bytes memory data,
                            string memory errorMessage
                        ) internal returns (bytes memory) {
                            return _functionCallWithValue(target, data, 0, errorMessage);
                        }
                    
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but also transferring `value` wei to `target`.
                         *
                         * Requirements:
                         *
                         * - the calling contract must have an ETH balance of at least `value`.
                         * - the called Solidity function must be `payable`.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(
                            address target,
                            bytes memory data,
                            uint256 value
                        ) internal returns (bytes memory) {
                            return
                                functionCallWithValue(
                                    target,
                                    data,
                                    value,
                                    "Address: low-level call with value failed"
                                );
                        }
                    
                        /**
                         * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
                         * with `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(
                            address target,
                            bytes memory data,
                            uint256 value,
                            string memory errorMessage
                        ) internal returns (bytes memory) {
                            require(
                                address(this).balance >= value,
                                "Address: insufficient balance for call"
                            );
                            return _functionCallWithValue(target, data, value, errorMessage);
                        }
                    
                        function _functionCallWithValue(
                            address target,
                            bytes memory data,
                            uint256 weiValue,
                            string memory errorMessage
                        ) private returns (bytes memory) {
                            require(isContract(target), "Address: call to non-contract");
                    
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.call{
                                value: weiValue
                            }(data);
                            if (success) {
                                return returndata;
                            } else {
                                // Look for revert reason and bubble it up if present
                                if (returndata.length > 0) {
                                    // The easiest way to bubble the revert reason is using memory via assembly
                    
                                    // solhint-disable-next-line no-inline-assembly
                                    assembly {
                                        let returndata_size := mload(returndata)
                                        revert(add(32, returndata), returndata_size)
                                    }
                                } else {
                                    revert(errorMessage);
                                }
                            }
                        }
                    }
                    
                    // File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol
                    
                    pragma solidity ^0.6.0;
                    
                    /**
                     * @title SafeERC20
                     * @dev Wrappers around ERC20 operations that throw on failure (when the token
                     * contract returns false). Tokens that return no value (and instead revert or
                     * throw on failure) are also supported, non-reverting calls are assumed to be
                     * successful.
                     * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
                     * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
                     */
                    library SafeERC20 {
                        using SafeMath for uint256;
                        using Address for address;
                    
                        function safeTransfer(
                            IERC20 token,
                            address to,
                            uint256 value
                        ) internal {
                            _callOptionalReturn(
                                token,
                                abi.encodeWithSelector(token.transfer.selector, to, value)
                            );
                        }
                    
                        function safeTransferFrom(
                            IERC20 token,
                            address from,
                            address to,
                            uint256 value
                        ) internal {
                            _callOptionalReturn(
                                token,
                                abi.encodeWithSelector(token.transferFrom.selector, from, to, value)
                            );
                        }
                    
                        /**
                         * @dev Deprecated. This function has issues similar to the ones found in
                         * {IERC20-approve}, and its usage is discouraged.
                         *
                         * Whenever possible, use {safeIncreaseAllowance} and
                         * {safeDecreaseAllowance} instead.
                         */
                        function safeApprove(
                            IERC20 token,
                            address spender,
                            uint256 value
                        ) internal {
                            // safeApprove should only be called when setting an initial allowance,
                            // or when resetting it to zero. To increase and decrease it, use
                            // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
                            // solhint-disable-next-line max-line-length
                            require(
                                (value == 0) || (token.allowance(address(this), spender) == 0),
                                "SafeERC20: approve from non-zero to non-zero allowance"
                            );
                            _callOptionalReturn(
                                token,
                                abi.encodeWithSelector(token.approve.selector, spender, value)
                            );
                        }
                    
                        function safeIncreaseAllowance(
                            IERC20 token,
                            address spender,
                            uint256 value
                        ) internal {
                            uint256 newAllowance = token.allowance(address(this), spender).add(
                                value
                            );
                            _callOptionalReturn(
                                token,
                                abi.encodeWithSelector(
                                    token.approve.selector,
                                    spender,
                                    newAllowance
                                )
                            );
                        }
                    
                        function safeDecreaseAllowance(
                            IERC20 token,
                            address spender,
                            uint256 value
                        ) internal {
                            uint256 newAllowance = token.allowance(address(this), spender).sub(
                                value,
                                "SafeERC20: decreased allowance below zero"
                            );
                            _callOptionalReturn(
                                token,
                                abi.encodeWithSelector(
                                    token.approve.selector,
                                    spender,
                                    newAllowance
                                )
                            );
                        }
                    
                        /**
                         * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
                         * on the return value: the return value is optional (but if data is returned, it must not be false).
                         * @param token The token targeted by the call.
                         * @param data The call data (encoded using abi.encode or one of its variants).
                         */
                        function _callOptionalReturn(IERC20 token, bytes memory data) private {
                            // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
                            // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
                            // the target address contains contract code and also asserts for success in the low-level call.
                    
                            bytes memory returndata = address(token).functionCall(
                                data,
                                "SafeERC20: low-level call failed"
                            );
                            if (returndata.length > 0) {
                                // Return data is optional
                                // solhint-disable-next-line max-line-length
                                require(
                                    abi.decode(returndata, (bool)),
                                    "SafeERC20: ERC20 operation did not succeed"
                                );
                            }
                        }
                    }
                    
                    // File: contracts/v1.1/Rescuable.sol
                    
                    /**
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    contract Rescuable is Ownable {
                        using SafeERC20 for IERC20;
                    
                        address private _rescuer;
                    
                        event RescuerChanged(address indexed newRescuer);
                    
                        /**
                         * @notice Returns current rescuer
                         * @return Rescuer's address
                         */
                        function rescuer() external view returns (address) {
                            return _rescuer;
                        }
                    
                        /**
                         * @notice Revert if called by any account other than the rescuer.
                         */
                        modifier onlyRescuer() {
                            require(msg.sender == _rescuer, "Rescuable: caller is not the rescuer");
                            _;
                        }
                    
                        /**
                         * @notice Rescue ERC20 tokens locked up in this contract.
                         * @param tokenContract ERC20 token contract address
                         * @param to        Recipient address
                         * @param amount    Amount to withdraw
                         */
                        function rescueERC20(
                            IERC20 tokenContract,
                            address to,
                            uint256 amount
                        ) external onlyRescuer {
                            tokenContract.safeTransfer(to, amount);
                        }
                    
                        /**
                         * @notice Assign the rescuer role to a given address.
                         * @param newRescuer New rescuer's address
                         */
                        function updateRescuer(address newRescuer) external onlyOwner {
                            require(
                                newRescuer != address(0),
                                "Rescuable: new rescuer is the zero address"
                            );
                            _rescuer = newRescuer;
                            emit RescuerChanged(newRescuer);
                        }
                    }
                    
                    // File: contracts/v1.1/FiatTokenV1_1.sol
                    
                    /**
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    /**
                     * @title FiatTokenV1_1
                     * @dev ERC20 Token backed by fiat reserves
                     */
                    contract FiatTokenV1_1 is FiatTokenV1, Rescuable {
                    
                    }
                    
                    // File: contracts/v2/AbstractFiatTokenV2.sol
                    
                    /**
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    abstract contract AbstractFiatTokenV2 is AbstractFiatTokenV1 {
                        function _increaseAllowance(
                            address owner,
                            address spender,
                            uint256 increment
                        ) internal virtual;
                    
                        function _decreaseAllowance(
                            address owner,
                            address spender,
                            uint256 decrement
                        ) internal virtual;
                    }
                    
                    // File: contracts/util/ECRecover.sol
                    
                    /**
                     * Copyright (c) 2016-2019 zOS Global Limited
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    /**
                     * @title ECRecover
                     * @notice A library that provides a safe ECDSA recovery function
                     */
                    library ECRecover {
                        /**
                         * @notice Recover signer's address from a signed message
                         * @dev Adapted from: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/65e4ffde586ec89af3b7e9140bdc9235d1254853/contracts/cryptography/ECDSA.sol
                         * Modifications: Accept v, r, and s as separate arguments
                         * @param digest    Keccak-256 hash digest of the signed message
                         * @param v         v of the signature
                         * @param r         r of the signature
                         * @param s         s of the signature
                         * @return Signer address
                         */
                        function recover(
                            bytes32 digest,
                            uint8 v,
                            bytes32 r,
                            bytes32 s
                        ) internal pure returns (address) {
                            // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
                            // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
                            // the valid range for s in (281): 0 < s < secp256k1n ÷ 2 + 1, and for v in (282): v ∈ {27, 28}. Most
                            // signatures from current libraries generate a unique signature with an s-value in the lower half order.
                            //
                            // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
                            // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
                            // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
                            // these malleable signatures as well.
                            if (
                                uint256(s) >
                                0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0
                            ) {
                                revert("ECRecover: invalid signature 's' value");
                            }
                    
                            if (v != 27 && v != 28) {
                                revert("ECRecover: invalid signature 'v' value");
                            }
                    
                            // If the signature is valid (and not malleable), return the signer address
                            address signer = ecrecover(digest, v, r, s);
                            require(signer != address(0), "ECRecover: invalid signature");
                    
                            return signer;
                        }
                    }
                    
                    // File: contracts/util/EIP712.sol
                    
                    /**
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    /**
                     * @title EIP712
                     * @notice A library that provides EIP712 helper functions
                     */
                    library EIP712 {
                        /**
                         * @notice Make EIP712 domain separator
                         * @param name      Contract name
                         * @param version   Contract version
                         * @return Domain separator
                         */
                        function makeDomainSeparator(string memory name, string memory version)
                            internal
                            view
                            returns (bytes32)
                        {
                            uint256 chainId;
                            assembly {
                                chainId := chainid()
                            }
                            return
                                keccak256(
                                    abi.encode(
                                        // keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)")
                                        0x8b73c3c69bb8fe3d512ecc4cf759cc79239f7b179b0ffacaa9a75d522b39400f,
                                        keccak256(bytes(name)),
                                        keccak256(bytes(version)),
                                        chainId,
                                        address(this)
                                    )
                                );
                        }
                    
                        /**
                         * @notice Recover signer's address from a EIP712 signature
                         * @param domainSeparator   Domain separator
                         * @param v                 v of the signature
                         * @param r                 r of the signature
                         * @param s                 s of the signature
                         * @param typeHashAndData   Type hash concatenated with data
                         * @return Signer's address
                         */
                        function recover(
                            bytes32 domainSeparator,
                            uint8 v,
                            bytes32 r,
                            bytes32 s,
                            bytes memory typeHashAndData
                        ) internal pure returns (address) {
                            bytes32 digest = keccak256(
                                abi.encodePacked(
                                    "\x19\x01",
                                    domainSeparator,
                                    keccak256(typeHashAndData)
                                )
                            );
                            return ECRecover.recover(digest, v, r, s);
                        }
                    }
                    
                    // File: contracts/v2/EIP712Domain.sol
                    
                    /**
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    /**
                     * @title EIP712 Domain
                     */
                    contract EIP712Domain {
                        /**
                         * @dev EIP712 Domain Separator
                         */
                        bytes32 public DOMAIN_SEPARATOR;
                    }
                    
                    // File: contracts/v2/EIP3009.sol
                    
                    /**
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    /**
                     * @title EIP-3009
                     * @notice Provide internal implementation for gas-abstracted transfers
                     * @dev Contracts that inherit from this must wrap these with publicly
                     * accessible functions, optionally adding modifiers where necessary
                     */
                    abstract contract EIP3009 is AbstractFiatTokenV2, EIP712Domain {
                        // keccak256("TransferWithAuthorization(address from,address to,uint256 value,uint256 validAfter,uint256 validBefore,bytes32 nonce)")
                        bytes32
                            public constant TRANSFER_WITH_AUTHORIZATION_TYPEHASH = 0x7c7c6cdb67a18743f49ec6fa9b35f50d52ed05cbed4cc592e13b44501c1a2267;
                    
                        // keccak256("ReceiveWithAuthorization(address from,address to,uint256 value,uint256 validAfter,uint256 validBefore,bytes32 nonce)")
                        bytes32
                            public constant RECEIVE_WITH_AUTHORIZATION_TYPEHASH = 0xd099cc98ef71107a616c4f0f941f04c322d8e254fe26b3c6668db87aae413de8;
                    
                        // keccak256("CancelAuthorization(address authorizer,bytes32 nonce)")
                        bytes32
                            public constant CANCEL_AUTHORIZATION_TYPEHASH = 0x158b0a9edf7a828aad02f63cd515c68ef2f50ba807396f6d12842833a1597429;
                    
                        /**
                         * @dev authorizer address => nonce => bool (true if nonce is used)
                         */
                        mapping(address => mapping(bytes32 => bool)) private _authorizationStates;
                    
                        event AuthorizationUsed(address indexed authorizer, bytes32 indexed nonce);
                        event AuthorizationCanceled(
                            address indexed authorizer,
                            bytes32 indexed nonce
                        );
                    
                        /**
                         * @notice Returns the state of an authorization
                         * @dev Nonces are randomly generated 32-byte data unique to the
                         * authorizer's address
                         * @param authorizer    Authorizer's address
                         * @param nonce         Nonce of the authorization
                         * @return True if the nonce is used
                         */
                        function authorizationState(address authorizer, bytes32 nonce)
                            external
                            view
                            returns (bool)
                        {
                            return _authorizationStates[authorizer][nonce];
                        }
                    
                        /**
                         * @notice Execute a transfer with a signed authorization
                         * @param from          Payer's address (Authorizer)
                         * @param to            Payee's address
                         * @param value         Amount to be transferred
                         * @param validAfter    The time after which this is valid (unix time)
                         * @param validBefore   The time before which this is valid (unix time)
                         * @param nonce         Unique nonce
                         * @param v             v of the signature
                         * @param r             r of the signature
                         * @param s             s of the signature
                         */
                        function _transferWithAuthorization(
                            address from,
                            address to,
                            uint256 value,
                            uint256 validAfter,
                            uint256 validBefore,
                            bytes32 nonce,
                            uint8 v,
                            bytes32 r,
                            bytes32 s
                        ) internal {
                            _requireValidAuthorization(from, nonce, validAfter, validBefore);
                    
                            bytes memory data = abi.encode(
                                TRANSFER_WITH_AUTHORIZATION_TYPEHASH,
                                from,
                                to,
                                value,
                                validAfter,
                                validBefore,
                                nonce
                            );
                            require(
                                EIP712.recover(DOMAIN_SEPARATOR, v, r, s, data) == from,
                                "FiatTokenV2: invalid signature"
                            );
                    
                            _markAuthorizationAsUsed(from, nonce);
                            _transfer(from, to, value);
                        }
                    
                        /**
                         * @notice Receive a transfer with a signed authorization from the payer
                         * @dev This has an additional check to ensure that the payee's address
                         * matches the caller of this function to prevent front-running attacks.
                         * @param from          Payer's address (Authorizer)
                         * @param to            Payee's address
                         * @param value         Amount to be transferred
                         * @param validAfter    The time after which this is valid (unix time)
                         * @param validBefore   The time before which this is valid (unix time)
                         * @param nonce         Unique nonce
                         * @param v             v of the signature
                         * @param r             r of the signature
                         * @param s             s of the signature
                         */
                        function _receiveWithAuthorization(
                            address from,
                            address to,
                            uint256 value,
                            uint256 validAfter,
                            uint256 validBefore,
                            bytes32 nonce,
                            uint8 v,
                            bytes32 r,
                            bytes32 s
                        ) internal {
                            require(to == msg.sender, "FiatTokenV2: caller must be the payee");
                            _requireValidAuthorization(from, nonce, validAfter, validBefore);
                    
                            bytes memory data = abi.encode(
                                RECEIVE_WITH_AUTHORIZATION_TYPEHASH,
                                from,
                                to,
                                value,
                                validAfter,
                                validBefore,
                                nonce
                            );
                            require(
                                EIP712.recover(DOMAIN_SEPARATOR, v, r, s, data) == from,
                                "FiatTokenV2: invalid signature"
                            );
                    
                            _markAuthorizationAsUsed(from, nonce);
                            _transfer(from, to, value);
                        }
                    
                        /**
                         * @notice Attempt to cancel an authorization
                         * @param authorizer    Authorizer's address
                         * @param nonce         Nonce of the authorization
                         * @param v             v of the signature
                         * @param r             r of the signature
                         * @param s             s of the signature
                         */
                        function _cancelAuthorization(
                            address authorizer,
                            bytes32 nonce,
                            uint8 v,
                            bytes32 r,
                            bytes32 s
                        ) internal {
                            _requireUnusedAuthorization(authorizer, nonce);
                    
                            bytes memory data = abi.encode(
                                CANCEL_AUTHORIZATION_TYPEHASH,
                                authorizer,
                                nonce
                            );
                            require(
                                EIP712.recover(DOMAIN_SEPARATOR, v, r, s, data) == authorizer,
                                "FiatTokenV2: invalid signature"
                            );
                    
                            _authorizationStates[authorizer][nonce] = true;
                            emit AuthorizationCanceled(authorizer, nonce);
                        }
                    
                        /**
                         * @notice Check that an authorization is unused
                         * @param authorizer    Authorizer's address
                         * @param nonce         Nonce of the authorization
                         */
                        function _requireUnusedAuthorization(address authorizer, bytes32 nonce)
                            private
                            view
                        {
                            require(
                                !_authorizationStates[authorizer][nonce],
                                "FiatTokenV2: authorization is used or canceled"
                            );
                        }
                    
                        /**
                         * @notice Check that authorization is valid
                         * @param authorizer    Authorizer's address
                         * @param nonce         Nonce of the authorization
                         * @param validAfter    The time after which this is valid (unix time)
                         * @param validBefore   The time before which this is valid (unix time)
                         */
                        function _requireValidAuthorization(
                            address authorizer,
                            bytes32 nonce,
                            uint256 validAfter,
                            uint256 validBefore
                        ) private view {
                            require(
                                now > validAfter,
                                "FiatTokenV2: authorization is not yet valid"
                            );
                            require(now < validBefore, "FiatTokenV2: authorization is expired");
                            _requireUnusedAuthorization(authorizer, nonce);
                        }
                    
                        /**
                         * @notice Mark an authorization as used
                         * @param authorizer    Authorizer's address
                         * @param nonce         Nonce of the authorization
                         */
                        function _markAuthorizationAsUsed(address authorizer, bytes32 nonce)
                            private
                        {
                            _authorizationStates[authorizer][nonce] = true;
                            emit AuthorizationUsed(authorizer, nonce);
                        }
                    }
                    
                    // File: contracts/v2/EIP2612.sol
                    
                    /**
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    /**
                     * @title EIP-2612
                     * @notice Provide internal implementation for gas-abstracted approvals
                     */
                    abstract contract EIP2612 is AbstractFiatTokenV2, EIP712Domain {
                        // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)")
                        bytes32
                            public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
                    
                        mapping(address => uint256) private _permitNonces;
                    
                        /**
                         * @notice Nonces for permit
                         * @param owner Token owner's address (Authorizer)
                         * @return Next nonce
                         */
                        function nonces(address owner) external view returns (uint256) {
                            return _permitNonces[owner];
                        }
                    
                        /**
                         * @notice Verify a signed approval permit and execute if valid
                         * @param owner     Token owner's address (Authorizer)
                         * @param spender   Spender's address
                         * @param value     Amount of allowance
                         * @param deadline  The time at which this expires (unix time)
                         * @param v         v of the signature
                         * @param r         r of the signature
                         * @param s         s of the signature
                         */
                        function _permit(
                            address owner,
                            address spender,
                            uint256 value,
                            uint256 deadline,
                            uint8 v,
                            bytes32 r,
                            bytes32 s
                        ) internal {
                            require(deadline >= now, "FiatTokenV2: permit is expired");
                    
                            bytes memory data = abi.encode(
                                PERMIT_TYPEHASH,
                                owner,
                                spender,
                                value,
                                _permitNonces[owner]++,
                                deadline
                            );
                            require(
                                EIP712.recover(DOMAIN_SEPARATOR, v, r, s, data) == owner,
                                "EIP2612: invalid signature"
                            );
                    
                            _approve(owner, spender, value);
                        }
                    }
                    
                    // File: contracts/v2/FiatTokenV2.sol
                    
                    /**
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    /**
                     * @title FiatToken V2
                     * @notice ERC20 Token backed by fiat reserves, version 2
                     */
                    contract FiatTokenV2 is FiatTokenV1_1, EIP3009, EIP2612 {
                        uint8 internal _initializedVersion;
                    
                        /**
                         * @notice Initialize v2
                         * @param newName   New token name
                         */
                        function initializeV2(string calldata newName) external {
                            // solhint-disable-next-line reason-string
                            require(initialized && _initializedVersion == 0);
                            name = newName;
                            DOMAIN_SEPARATOR = EIP712.makeDomainSeparator(newName, "2");
                            _initializedVersion = 1;
                        }
                    
                        /**
                         * @notice Increase the allowance by a given increment
                         * @param spender   Spender's address
                         * @param increment Amount of increase in allowance
                         * @return True if successful
                         */
                        function increaseAllowance(address spender, uint256 increment)
                            external
                            whenNotPaused
                            notBlacklisted(msg.sender)
                            notBlacklisted(spender)
                            returns (bool)
                        {
                            _increaseAllowance(msg.sender, spender, increment);
                            return true;
                        }
                    
                        /**
                         * @notice Decrease the allowance by a given decrement
                         * @param spender   Spender's address
                         * @param decrement Amount of decrease in allowance
                         * @return True if successful
                         */
                        function decreaseAllowance(address spender, uint256 decrement)
                            external
                            whenNotPaused
                            notBlacklisted(msg.sender)
                            notBlacklisted(spender)
                            returns (bool)
                        {
                            _decreaseAllowance(msg.sender, spender, decrement);
                            return true;
                        }
                    
                        /**
                         * @notice Execute a transfer with a signed authorization
                         * @param from          Payer's address (Authorizer)
                         * @param to            Payee's address
                         * @param value         Amount to be transferred
                         * @param validAfter    The time after which this is valid (unix time)
                         * @param validBefore   The time before which this is valid (unix time)
                         * @param nonce         Unique nonce
                         * @param v             v of the signature
                         * @param r             r of the signature
                         * @param s             s of the signature
                         */
                        function transferWithAuthorization(
                            address from,
                            address to,
                            uint256 value,
                            uint256 validAfter,
                            uint256 validBefore,
                            bytes32 nonce,
                            uint8 v,
                            bytes32 r,
                            bytes32 s
                        ) external whenNotPaused notBlacklisted(from) notBlacklisted(to) {
                            _transferWithAuthorization(
                                from,
                                to,
                                value,
                                validAfter,
                                validBefore,
                                nonce,
                                v,
                                r,
                                s
                            );
                        }
                    
                        /**
                         * @notice Receive a transfer with a signed authorization from the payer
                         * @dev This has an additional check to ensure that the payee's address
                         * matches the caller of this function to prevent front-running attacks.
                         * @param from          Payer's address (Authorizer)
                         * @param to            Payee's address
                         * @param value         Amount to be transferred
                         * @param validAfter    The time after which this is valid (unix time)
                         * @param validBefore   The time before which this is valid (unix time)
                         * @param nonce         Unique nonce
                         * @param v             v of the signature
                         * @param r             r of the signature
                         * @param s             s of the signature
                         */
                        function receiveWithAuthorization(
                            address from,
                            address to,
                            uint256 value,
                            uint256 validAfter,
                            uint256 validBefore,
                            bytes32 nonce,
                            uint8 v,
                            bytes32 r,
                            bytes32 s
                        ) external whenNotPaused notBlacklisted(from) notBlacklisted(to) {
                            _receiveWithAuthorization(
                                from,
                                to,
                                value,
                                validAfter,
                                validBefore,
                                nonce,
                                v,
                                r,
                                s
                            );
                        }
                    
                        /**
                         * @notice Attempt to cancel an authorization
                         * @dev Works only if the authorization is not yet used.
                         * @param authorizer    Authorizer's address
                         * @param nonce         Nonce of the authorization
                         * @param v             v of the signature
                         * @param r             r of the signature
                         * @param s             s of the signature
                         */
                        function cancelAuthorization(
                            address authorizer,
                            bytes32 nonce,
                            uint8 v,
                            bytes32 r,
                            bytes32 s
                        ) external whenNotPaused {
                            _cancelAuthorization(authorizer, nonce, v, r, s);
                        }
                    
                        /**
                         * @notice Update allowance with a signed permit
                         * @param owner       Token owner's address (Authorizer)
                         * @param spender     Spender's address
                         * @param value       Amount of allowance
                         * @param deadline    Expiration time, seconds since the epoch
                         * @param v           v of the signature
                         * @param r           r of the signature
                         * @param s           s of the signature
                         */
                        function permit(
                            address owner,
                            address spender,
                            uint256 value,
                            uint256 deadline,
                            uint8 v,
                            bytes32 r,
                            bytes32 s
                        ) external whenNotPaused notBlacklisted(owner) notBlacklisted(spender) {
                            _permit(owner, spender, value, deadline, v, r, s);
                        }
                    
                        /**
                         * @notice Internal function to increase the allowance by a given increment
                         * @param owner     Token owner's address
                         * @param spender   Spender's address
                         * @param increment Amount of increase
                         */
                        function _increaseAllowance(
                            address owner,
                            address spender,
                            uint256 increment
                        ) internal override {
                            _approve(owner, spender, allowed[owner][spender].add(increment));
                        }
                    
                        /**
                         * @notice Internal function to decrease the allowance by a given decrement
                         * @param owner     Token owner's address
                         * @param spender   Spender's address
                         * @param decrement Amount of decrease
                         */
                        function _decreaseAllowance(
                            address owner,
                            address spender,
                            uint256 decrement
                        ) internal override {
                            _approve(
                                owner,
                                spender,
                                allowed[owner][spender].sub(
                                    decrement,
                                    "ERC20: decreased allowance below zero"
                                )
                            );
                        }
                    }
                    
                    // File: contracts/v2/FiatTokenV2_1.sol
                    
                    /**
                     * Copyright (c) 2018-2020 CENTRE SECZ
                     *
                     * Permission is hereby granted, free of charge, to any person obtaining a copy
                     * of this software and associated documentation files (the "Software"), to deal
                     * in the Software without restriction, including without limitation the rights
                     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     * copies of the Software, and to permit persons to whom the Software is
                     * furnished to do so, subject to the following conditions:
                     *
                     * The above copyright notice and this permission notice shall be included in
                     * copies or substantial portions of the Software.
                     *
                     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                     * SOFTWARE.
                     */
                    
                    pragma solidity 0.6.12;
                    
                    // solhint-disable func-name-mixedcase
                    
                    /**
                     * @title FiatToken V2.1
                     * @notice ERC20 Token backed by fiat reserves, version 2.1
                     */
                    contract FiatTokenV2_1 is FiatTokenV2 {
                        /**
                         * @notice Initialize v2.1
                         * @param lostAndFound  The address to which the locked funds are sent
                         */
                        function initializeV2_1(address lostAndFound) external {
                            // solhint-disable-next-line reason-string
                            require(_initializedVersion == 1);
                    
                            uint256 lockedAmount = balances[address(this)];
                            if (lockedAmount > 0) {
                                _transfer(address(this), lostAndFound, lockedAmount);
                            }
                            blacklisted[address(this)] = true;
                    
                            _initializedVersion = 2;
                        }
                    
                        /**
                         * @notice Version string for the EIP712 domain separator
                         * @return Version string
                         */
                        function version() external view returns (string memory) {
                            return "2";
                        }
                    }

                    File 9 of 9: Inbox
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2019-2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "./interfaces/IInbox.sol";
                    import "./interfaces/IBridge.sol";
                    import "../rollup/Rollup.sol";
                    import "./Messages.sol";
                    import "../libraries/Cloneable.sol";
                    import "../libraries/Whitelist.sol";
                    import "../libraries/ProxyUtil.sol";
                    import "../libraries/AddressAliasHelper.sol";
                    import "@openzeppelin/contracts/utils/Address.sol";
                    import "./Bridge.sol";
                    contract Inbox is IInbox, WhitelistConsumer, Cloneable {
                        uint8 internal constant ETH_TRANSFER = 0;
                        uint8 internal constant L2_MSG = 3;
                        uint8 internal constant L1MessageType_L2FundedByL1 = 7;
                        uint8 internal constant L1MessageType_submitRetryableTx = 9;
                        uint8 internal constant L2MessageType_unsignedEOATx = 0;
                        uint8 internal constant L2MessageType_unsignedContractTx = 1;
                        IBridge public override bridge;
                        bool public isCreateRetryablePaused;
                        bool public shouldRewriteSender;
                        function initialize(IBridge _bridge, address _whitelist) external {
                            require(address(bridge) == address(0), "ALREADY_INIT");
                            bridge = _bridge;
                            WhitelistConsumer.whitelist = _whitelist;
                        }
                        /**
                         * @notice Send a generic L2 message to the chain
                         * @dev This method is an optimization to avoid having to emit the entirety of the messageData in a log. Instead validators are expected to be able to parse the data from the transaction's input
                         * @param messageData Data of the message being sent
                         */
                        function sendL2MessageFromOrigin(bytes calldata messageData)
                            external
                            onlyWhitelisted
                            returns (uint256)
                        {
                            // solhint-disable-next-line avoid-tx-origin
                            require(msg.sender == tx.origin, "origin only");
                            uint256 msgNum = deliverToBridge(L2_MSG, msg.sender, keccak256(messageData));
                            emit InboxMessageDeliveredFromOrigin(msgNum);
                            return msgNum;
                        }
                        /**
                         * @notice Send a generic L2 message to the chain
                         * @dev This method can be used to send any type of message that doesn't require L1 validation
                         * @param messageData Data of the message being sent
                         */
                        function sendL2Message(bytes calldata messageData)
                            external
                            override
                            onlyWhitelisted
                            returns (uint256)
                        {
                            uint256 msgNum = deliverToBridge(L2_MSG, msg.sender, keccak256(messageData));
                            emit InboxMessageDelivered(msgNum, messageData);
                            return msgNum;
                        }
                        function sendL1FundedUnsignedTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            uint256 nonce,
                            address destAddr,
                            bytes calldata data
                        ) external payable virtual override onlyWhitelisted returns (uint256) {
                            return
                                _deliverMessage(
                                    L1MessageType_L2FundedByL1,
                                    msg.sender,
                                    abi.encodePacked(
                                        L2MessageType_unsignedEOATx,
                                        maxGas,
                                        gasPriceBid,
                                        nonce,
                                        uint256(uint160(bytes20(destAddr))),
                                        msg.value,
                                        data
                                    )
                                );
                        }
                        function sendL1FundedContractTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            address destAddr,
                            bytes calldata data
                        ) external payable virtual override onlyWhitelisted returns (uint256) {
                            return
                                _deliverMessage(
                                    L1MessageType_L2FundedByL1,
                                    msg.sender,
                                    abi.encodePacked(
                                        L2MessageType_unsignedContractTx,
                                        maxGas,
                                        gasPriceBid,
                                        uint256(uint160(bytes20(destAddr))),
                                        msg.value,
                                        data
                                    )
                                );
                        }
                        function sendUnsignedTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            uint256 nonce,
                            address destAddr,
                            uint256 amount,
                            bytes calldata data
                        ) external virtual override onlyWhitelisted returns (uint256) {
                            return
                                _deliverMessage(
                                    L2_MSG,
                                    msg.sender,
                                    abi.encodePacked(
                                        L2MessageType_unsignedEOATx,
                                        maxGas,
                                        gasPriceBid,
                                        nonce,
                                        uint256(uint160(bytes20(destAddr))),
                                        amount,
                                        data
                                    )
                                );
                        }
                        function sendContractTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            address destAddr,
                            uint256 amount,
                            bytes calldata data
                        ) external virtual override onlyWhitelisted returns (uint256) {
                            return
                                _deliverMessage(
                                    L2_MSG,
                                    msg.sender,
                                    abi.encodePacked(
                                        L2MessageType_unsignedContractTx,
                                        maxGas,
                                        gasPriceBid,
                                        uint256(uint160(bytes20(destAddr))),
                                        amount,
                                        data
                                    )
                                );
                        }
                        modifier onlyOwner() {
                            // the rollup contract owns the bridge
                            address rollup = Bridge(address(bridge)).owner();
                            // we want to validate the owner of the rollup
                            address owner = RollupBase(rollup).owner();
                            require(msg.sender == owner, "NOT_ROLLUP");
                            _;
                        }
                        event PauseToggled(bool enabled);
                        /// @notice pauses creating retryables
                        function pauseCreateRetryables() external override onlyOwner {
                            require(!isCreateRetryablePaused, "ALREADY_PAUSED");
                            isCreateRetryablePaused = true;
                            emit PauseToggled(true);
                        }
                        /// @notice unpauses creating retryables
                        function unpauseCreateRetryables() external override onlyOwner {
                            require(isCreateRetryablePaused, "NOT_PAUSED");
                            isCreateRetryablePaused = false;
                            emit PauseToggled(false);
                        }
                        event RewriteToggled(bool enabled);
                        /// @notice start rewriting addresses in eth deposits
                        function startRewriteAddress() external override onlyOwner {
                            require(!shouldRewriteSender, "ALREADY_REWRITING");
                            shouldRewriteSender = true;
                            emit RewriteToggled(true);
                        }
                        /// @notice stop rewriting addresses in eth deposits
                        function stopRewriteAddress() external override onlyOwner {
                            require(shouldRewriteSender, "NOT_REWRITING");
                            shouldRewriteSender = false;
                            emit RewriteToggled(false);
                        }
                        /// @notice deposit eth from L1 to L2
                        /// @dev this function should not be called inside contract constructors
                        function depositEth(uint256 maxSubmissionCost)
                            external
                            payable
                            virtual
                            override
                            onlyWhitelisted
                            returns (uint256)
                        {
                            require(!isCreateRetryablePaused, "CREATE_RETRYABLES_PAUSED");
                            address sender = msg.sender;
                            address destinationAddress = msg.sender;
                            if (shouldRewriteSender) {
                                if (!Address.isContract(sender) && tx.origin == msg.sender) {
                                    // isContract check fails if this function is called during a contract's constructor.
                                    // We don't adjust the address for calls coming from L1 contracts since their addresses get remapped
                                    // If the caller is an EOA, we adjust the address.
                                    // This is needed because unsigned messages to the L2 (such as retryables)
                                    // have the L1 sender address mapped.
                                    // Here we preemptively reverse the mapping for EOAs so deposits work as expected
                                    sender = AddressAliasHelper.undoL1ToL2Alias(sender);
                                } else {
                                    destinationAddress = AddressAliasHelper.applyL1ToL2Alias(destinationAddress);
                                }
                            }
                            return
                                _deliverMessage(
                                    L1MessageType_submitRetryableTx,
                                    sender,
                                    abi.encodePacked(
                                        // the beneficiary and other refund addresses don't get rewritten by arb-os
                                        // so we use the original msg.sender value
                                        uint256(uint160(bytes20(destinationAddress))),
                                        uint256(0),
                                        msg.value,
                                        maxSubmissionCost,
                                        uint256(uint160(bytes20(destinationAddress))),
                                        uint256(uint160(bytes20(destinationAddress))),
                                        uint256(0),
                                        uint256(0),
                                        uint256(0),
                                        ""
                                    )
                                );
                        }
                        /**
                         * @notice Put a message in the L2 inbox that can be reexecuted for some fixed amount of time if it reverts
                         * @dev Advanced usage only (does not rewrite aliases for excessFeeRefundAddress and callValueRefundAddress). createRetryableTicket method is the recommended standard.
                         * @param destAddr destination L2 contract address
                         * @param l2CallValue call value for retryable L2 message
                         * @param  maxSubmissionCost Max gas deducted from user's L2 balance to cover base submission fee
                         * @param excessFeeRefundAddress maxgas x gasprice - execution cost gets credited here on L2 balance
                         * @param callValueRefundAddress l2Callvalue gets credited here on L2 if retryable txn times out or gets cancelled
                         * @param maxGas Max gas deducted from user's L2 balance to cover L2 execution
                         * @param gasPriceBid price bid for L2 execution
                         * @param data ABI encoded data of L2 message
                         * @return unique id for retryable transaction (keccak256(requestID, uint(0) )
                         */
                        function createRetryableTicketNoRefundAliasRewrite(
                            address destAddr,
                            uint256 l2CallValue,
                            uint256 maxSubmissionCost,
                            address excessFeeRefundAddress,
                            address callValueRefundAddress,
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            bytes calldata data
                        ) public payable virtual onlyWhitelisted returns (uint256) {
                            require(!isCreateRetryablePaused, "CREATE_RETRYABLES_PAUSED");
                            return
                                _deliverMessage(
                                    L1MessageType_submitRetryableTx,
                                    msg.sender,
                                    abi.encodePacked(
                                        uint256(uint160(bytes20(destAddr))),
                                        l2CallValue,
                                        msg.value,
                                        maxSubmissionCost,
                                        uint256(uint160(bytes20(excessFeeRefundAddress))),
                                        uint256(uint160(bytes20(callValueRefundAddress))),
                                        maxGas,
                                        gasPriceBid,
                                        data.length,
                                        data
                                    )
                                );
                        }
                        /**
                         * @notice Put a message in the L2 inbox that can be reexecuted for some fixed amount of time if it reverts
                         * @dev all msg.value will deposited to callValueRefundAddress on L2
                         * @param destAddr destination L2 contract address
                         * @param l2CallValue call value for retryable L2 message
                         * @param  maxSubmissionCost Max gas deducted from user's L2 balance to cover base submission fee
                         * @param excessFeeRefundAddress maxgas x gasprice - execution cost gets credited here on L2 balance
                         * @param callValueRefundAddress l2Callvalue gets credited here on L2 if retryable txn times out or gets cancelled
                         * @param maxGas Max gas deducted from user's L2 balance to cover L2 execution
                         * @param gasPriceBid price bid for L2 execution
                         * @param data ABI encoded data of L2 message
                         * @return unique id for retryable transaction (keccak256(requestID, uint(0) )
                         */
                        function createRetryableTicket(
                            address destAddr,
                            uint256 l2CallValue,
                            uint256 maxSubmissionCost,
                            address excessFeeRefundAddress,
                            address callValueRefundAddress,
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            bytes calldata data
                        ) external payable virtual override onlyWhitelisted returns (uint256) {
                            // if a refund address is a contract, we apply the alias to it
                            // so that it can access its funds on the L2
                            // since the beneficiary and other refund addresses don't get rewritten by arb-os
                            if (shouldRewriteSender && Address.isContract(excessFeeRefundAddress)) {
                                excessFeeRefundAddress = AddressAliasHelper.applyL1ToL2Alias(excessFeeRefundAddress);
                            }
                            if (shouldRewriteSender && Address.isContract(callValueRefundAddress)) {
                                // this is the beneficiary. be careful since this is the address that can cancel the retryable in the L2
                                callValueRefundAddress = AddressAliasHelper.applyL1ToL2Alias(callValueRefundAddress);
                            }
                            return
                                createRetryableTicketNoRefundAliasRewrite(
                                    destAddr,
                                    l2CallValue,
                                    maxSubmissionCost,
                                    excessFeeRefundAddress,
                                    callValueRefundAddress,
                                    maxGas,
                                    gasPriceBid,
                                    data
                                );
                        }
                        function _deliverMessage(
                            uint8 _kind,
                            address _sender,
                            bytes memory _messageData
                        ) internal returns (uint256) {
                            uint256 msgNum = deliverToBridge(_kind, _sender, keccak256(_messageData));
                            emit InboxMessageDelivered(msgNum, _messageData);
                            return msgNum;
                        }
                        function deliverToBridge(
                            uint8 kind,
                            address sender,
                            bytes32 messageDataHash
                        ) internal returns (uint256) {
                            return bridge.deliverMessageToInbox{ value: msg.value }(kind, sender, messageDataHash);
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "./IBridge.sol";
                    import "./IMessageProvider.sol";
                    interface IInbox is IMessageProvider {
                        function sendL2Message(bytes calldata messageData) external returns (uint256);
                        function sendUnsignedTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            uint256 nonce,
                            address destAddr,
                            uint256 amount,
                            bytes calldata data
                        ) external returns (uint256);
                        function sendContractTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            address destAddr,
                            uint256 amount,
                            bytes calldata data
                        ) external returns (uint256);
                        function sendL1FundedUnsignedTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            uint256 nonce,
                            address destAddr,
                            bytes calldata data
                        ) external payable returns (uint256);
                        function sendL1FundedContractTransaction(
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            address destAddr,
                            bytes calldata data
                        ) external payable returns (uint256);
                        function createRetryableTicket(
                            address destAddr,
                            uint256 arbTxCallValue,
                            uint256 maxSubmissionCost,
                            address submissionRefundAddress,
                            address valueRefundAddress,
                            uint256 maxGas,
                            uint256 gasPriceBid,
                            bytes calldata data
                        ) external payable returns (uint256);
                        function depositEth(uint256 maxSubmissionCost) external payable returns (uint256);
                        function bridge() external view returns (IBridge);
                        function pauseCreateRetryables() external;
                        function unpauseCreateRetryables() external;
                        function startRewriteAddress() external;
                        function stopRewriteAddress() external;
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface IBridge {
                        event MessageDelivered(
                            uint256 indexed messageIndex,
                            bytes32 indexed beforeInboxAcc,
                            address inbox,
                            uint8 kind,
                            address sender,
                            bytes32 messageDataHash
                        );
                        event BridgeCallTriggered(
                            address indexed outbox,
                            address indexed destAddr,
                            uint256 amount,
                            bytes data
                        );
                        event InboxToggle(address indexed inbox, bool enabled);
                        event OutboxToggle(address indexed outbox, bool enabled);
                        function deliverMessageToInbox(
                            uint8 kind,
                            address sender,
                            bytes32 messageDataHash
                        ) external payable returns (uint256);
                        function executeCall(
                            address destAddr,
                            uint256 amount,
                            bytes calldata data
                        ) external returns (bool success, bytes memory returnData);
                        // These are only callable by the admin
                        function setInbox(address inbox, bool enabled) external;
                        function setOutbox(address inbox, bool enabled) external;
                        // View functions
                        function activeOutbox() external view returns (address);
                        function allowedInboxes(address inbox) external view returns (bool);
                        function allowedOutboxes(address outbox) external view returns (bool);
                        function inboxAccs(uint256 index) external view returns (bytes32);
                        function messageCount() external view returns (uint256);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "@openzeppelin/contracts/utils/Pausable.sol";
                    import "@openzeppelin/contracts/proxy/Proxy.sol";
                    import "@openzeppelin/contracts/utils/Address.sol";
                    import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
                    import "./RollupEventBridge.sol";
                    import "./RollupCore.sol";
                    import "./RollupLib.sol";
                    import "./INode.sol";
                    import "./INodeFactory.sol";
                    import "../challenge/IChallenge.sol";
                    import "../challenge/IChallengeFactory.sol";
                    import "../bridge/interfaces/IBridge.sol";
                    import "../bridge/interfaces/IOutbox.sol";
                    import "../bridge/Messages.sol";
                    import "../libraries/ProxyUtil.sol";
                    import "../libraries/Cloneable.sol";
                    import "./facets/IRollupFacets.sol";
                    abstract contract RollupBase is Cloneable, RollupCore, Pausable {
                        // Rollup Config
                        uint256 public confirmPeriodBlocks;
                        uint256 public extraChallengeTimeBlocks;
                        uint256 public avmGasSpeedLimitPerBlock;
                        uint256 public baseStake;
                        // Bridge is an IInbox and IOutbox
                        IBridge public delayedBridge;
                        ISequencerInbox public sequencerBridge;
                        IOutbox public outbox;
                        RollupEventBridge public rollupEventBridge;
                        IChallengeFactory public challengeFactory;
                        INodeFactory public nodeFactory;
                        address public owner;
                        address public stakeToken;
                        uint256 public minimumAssertionPeriod;
                        uint256 public STORAGE_GAP_1;
                        uint256 public STORAGE_GAP_2;
                        uint256 public challengeExecutionBisectionDegree;
                        address[] internal facets;
                        mapping(address => bool) isValidator;
                        /// @notice DEPRECATED -- this method is deprecated but still mantained for backward compatibility
                        /// @dev this actually returns the avmGasSpeedLimitPerBlock
                        /// @return this actually returns the avmGasSpeedLimitPerBlock
                        function arbGasSpeedLimitPerBlock() external view returns (uint256) {
                            return avmGasSpeedLimitPerBlock;
                        }
                    }
                    contract Rollup is Proxy, RollupBase {
                        using Address for address;
                        constructor(uint256 _confirmPeriodBlocks) public Cloneable() Pausable() {
                            // constructor is used so logic contract can't be init'ed
                            confirmPeriodBlocks = _confirmPeriodBlocks;
                            require(isInit(), "CONSTRUCTOR_NOT_INIT");
                        }
                        function isInit() internal view returns (bool) {
                            return confirmPeriodBlocks != 0;
                        }
                        // _rollupParams = [ confirmPeriodBlocks, extraChallengeTimeBlocks, avmGasSpeedLimitPerBlock, baseStake ]
                        // connectedContracts = [delayedBridge, sequencerInbox, outbox, rollupEventBridge, challengeFactory, nodeFactory]
                        function initialize(
                            bytes32 _machineHash,
                            uint256[4] calldata _rollupParams,
                            address _stakeToken,
                            address _owner,
                            bytes calldata _extraConfig,
                            address[6] calldata connectedContracts,
                            address[2] calldata _facets,
                            uint256[2] calldata sequencerInboxParams
                        ) public {
                            require(!isInit(), "ALREADY_INIT");
                            // calls initialize method in user facet
                            require(_facets[0].isContract(), "FACET_0_NOT_CONTRACT");
                            require(_facets[1].isContract(), "FACET_1_NOT_CONTRACT");
                            (bool success, ) = _facets[1].delegatecall(
                                abi.encodeWithSelector(IRollupUser.initialize.selector, _stakeToken)
                            );
                            require(success, "FAIL_INIT_FACET");
                            delayedBridge = IBridge(connectedContracts[0]);
                            sequencerBridge = ISequencerInbox(connectedContracts[1]);
                            outbox = IOutbox(connectedContracts[2]);
                            delayedBridge.setOutbox(connectedContracts[2], true);
                            rollupEventBridge = RollupEventBridge(connectedContracts[3]);
                            delayedBridge.setInbox(connectedContracts[3], true);
                            rollupEventBridge.rollupInitialized(
                                _rollupParams[0],
                                _rollupParams[2],
                                _owner,
                                _extraConfig
                            );
                            challengeFactory = IChallengeFactory(connectedContracts[4]);
                            nodeFactory = INodeFactory(connectedContracts[5]);
                            INode node = createInitialNode(_machineHash);
                            initializeCore(node);
                            confirmPeriodBlocks = _rollupParams[0];
                            extraChallengeTimeBlocks = _rollupParams[1];
                            avmGasSpeedLimitPerBlock = _rollupParams[2];
                            baseStake = _rollupParams[3];
                            owner = _owner;
                            // A little over 15 minutes
                            minimumAssertionPeriod = 75;
                            challengeExecutionBisectionDegree = 400;
                            sequencerBridge.setMaxDelay(sequencerInboxParams[0], sequencerInboxParams[1]);
                            // facets[0] == admin, facets[1] == user
                            facets = _facets;
                            emit RollupCreated(_machineHash);
                            require(isInit(), "INITIALIZE_NOT_INIT");
                        }
                        function postUpgradeInit() external {
                            // it is assumed the rollup contract is behind a Proxy controlled by a proxy admin
                            // this function can only be called by the proxy admin contract
                            address proxyAdmin = ProxyUtil.getProxyAdmin();
                            require(msg.sender == proxyAdmin, "NOT_FROM_ADMIN");
                            // this upgrade moves the delay blocks and seconds tracking to the sequencer inbox
                            // because of that we need to update the admin facet logic to allow the owner to set
                            // these values in the sequencer inbox
                            STORAGE_GAP_1 = 0;
                            STORAGE_GAP_2 = 0;
                        }
                        function createInitialNode(bytes32 _machineHash) private returns (INode) {
                            bytes32 state = RollupLib.stateHash(
                                RollupLib.ExecutionState(
                                    0, // total gas used
                                    _machineHash,
                                    0, // inbox count
                                    0, // send count
                                    0, // log count
                                    0, // send acc
                                    0, // log acc
                                    block.number, // block proposed
                                    1 // Initialization message already in inbox
                                )
                            );
                            return
                                INode(
                                    nodeFactory.createNode(
                                        state,
                                        0, // challenge hash (not challengeable)
                                        0, // confirm data
                                        0, // prev node
                                        block.number // deadline block (not challengeable)
                                    )
                                );
                        }
                        /**
                         * This contract uses a dispatch pattern from EIP-2535: Diamonds
                         * together with Open Zeppelin's proxy
                         */
                        function getFacets() external view returns (address, address) {
                            return (getAdminFacet(), getUserFacet());
                        }
                        function getAdminFacet() public view returns (address) {
                            return facets[0];
                        }
                        function getUserFacet() public view returns (address) {
                            return facets[1];
                        }
                        /**
                         * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
                         * and {_fallback} should delegate.
                         */
                        function _implementation() internal view virtual override returns (address) {
                            require(msg.data.length >= 4, "NO_FUNC_SIG");
                            address rollupOwner = owner;
                            // if there is an owner and it is the sender, delegate to admin facet
                            address target = rollupOwner != address(0) && rollupOwner == msg.sender
                                ? getAdminFacet()
                                : getUserFacet();
                            require(target.isContract(), "TARGET_NOT_CONTRACT");
                            return target;
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2019-2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    library Messages {
                        function messageHash(
                            uint8 kind,
                            address sender,
                            uint256 blockNumber,
                            uint256 timestamp,
                            uint256 inboxSeqNum,
                            uint256 gasPriceL1,
                            bytes32 messageDataHash
                        ) internal pure returns (bytes32) {
                            return
                                keccak256(
                                    abi.encodePacked(
                                        kind,
                                        sender,
                                        blockNumber,
                                        timestamp,
                                        inboxSeqNum,
                                        gasPriceL1,
                                        messageDataHash
                                    )
                                );
                        }
                        function addMessageToInbox(bytes32 inbox, bytes32 message) internal pure returns (bytes32) {
                            return keccak256(abi.encodePacked(inbox, message));
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2019-2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "./ICloneable.sol";
                    contract Cloneable is ICloneable {
                        string private constant NOT_CLONE = "NOT_CLONE";
                        bool private isMasterCopy;
                        constructor() public {
                            isMasterCopy = true;
                        }
                        function isMaster() external view override returns (bool) {
                            return isMasterCopy;
                        }
                        function safeSelfDestruct(address payable dest) internal {
                            require(!isMasterCopy, NOT_CLONE);
                            selfdestruct(dest);
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    abstract contract WhitelistConsumer {
                        address public whitelist;
                        event WhitelistSourceUpdated(address newSource);
                        modifier onlyWhitelisted {
                            if (whitelist != address(0)) {
                                require(Whitelist(whitelist).isAllowed(msg.sender), "NOT_WHITELISTED");
                            }
                            _;
                        }
                        function updateWhitelistSource(address newSource) external {
                            require(msg.sender == whitelist, "NOT_FROM_LIST");
                            whitelist = newSource;
                            emit WhitelistSourceUpdated(newSource);
                        }
                    }
                    contract Whitelist {
                        address public owner;
                        mapping(address => bool) public isAllowed;
                        event OwnerUpdated(address newOwner);
                        event WhitelistUpgraded(address newWhitelist, address[] targets);
                        constructor() public {
                            owner = msg.sender;
                        }
                        modifier onlyOwner {
                            require(msg.sender == owner, "ONLY_OWNER");
                            _;
                        }
                        function setOwner(address newOwner) external onlyOwner {
                            owner = newOwner;
                            emit OwnerUpdated(newOwner);
                        }
                        function setWhitelist(address[] memory user, bool[] memory val) external onlyOwner {
                            require(user.length == val.length, "INVALID_INPUT");
                            for (uint256 i = 0; i < user.length; i++) {
                                isAllowed[user[i]] = val[i];
                            }
                        }
                        // set new whitelist to address(0) to disable whitelist
                        function triggerConsumers(address newWhitelist, address[] memory targets) external onlyOwner {
                            for (uint256 i = 0; i < targets.length; i++) {
                                WhitelistConsumer(targets[i]).updateWhitelistSource(newWhitelist);
                            }
                            emit WhitelistUpgraded(newWhitelist, targets);
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    library ProxyUtil {
                        function getProxyAdmin() internal view returns (address admin) {
                            // https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v3.4.0/contracts/proxy/TransparentUpgradeableProxy.sol#L48
                            // Storage slot with the admin of the proxy contract.
                            // This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
                            bytes32 slot = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
                            assembly {
                                admin := sload(slot)
                            }
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2019-2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    library AddressAliasHelper {
                        uint160 constant offset = uint160(0x1111000000000000000000000000000000001111);
                        /// @notice Utility function that converts the msg.sender viewed in the L2 to the
                        /// address in the L1 that submitted a tx to the inbox
                        /// @param l1Address L2 address as viewed in msg.sender
                        /// @return l2Address the address in the L1 that triggered the tx to L2
                        function applyL1ToL2Alias(address l1Address) internal pure returns (address l2Address) {
                            l2Address = address(uint160(l1Address) + offset);
                        }
                        /// @notice Utility function that converts the msg.sender viewed in the L2 to the
                        /// address in the L1 that submitted a tx to the inbox
                        /// @param l2Address L2 address as viewed in msg.sender
                        /// @return l1Address the address in the L1 that triggered the tx to L2
                        function undoL1ToL2Alias(address l2Address) internal pure returns (address l1Address) {
                            l1Address = address(uint160(l2Address) - offset);
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.2 <0.8.0;
                    /**
                     * @dev Collection of functions related to the address type
                     */
                    library Address {
                        /**
                         * @dev Returns true if `account` is a contract.
                         *
                         * [IMPORTANT]
                         * ====
                         * It is unsafe to assume that an address for which this function returns
                         * false is an externally-owned account (EOA) and not a contract.
                         *
                         * Among others, `isContract` will return false for the following
                         * types of addresses:
                         *
                         *  - an externally-owned account
                         *  - a contract in construction
                         *  - an address where a contract will be created
                         *  - an address where a contract lived, but was destroyed
                         * ====
                         */
                        function isContract(address account) internal view returns (bool) {
                            // This method relies on extcodesize, which returns 0 for contracts in
                            // construction, since the code is only stored at the end of the
                            // constructor execution.
                            uint256 size;
                            // solhint-disable-next-line no-inline-assembly
                            assembly { size := extcodesize(account) }
                            return size > 0;
                        }
                        /**
                         * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
                         * `recipient`, forwarding all available gas and reverting on errors.
                         *
                         * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
                         * of certain opcodes, possibly making contracts go over the 2300 gas limit
                         * imposed by `transfer`, making them unable to receive funds via
                         * `transfer`. {sendValue} removes this limitation.
                         *
                         * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
                         *
                         * IMPORTANT: because control is transferred to `recipient`, care must be
                         * taken to not create reentrancy vulnerabilities. Consider using
                         * {ReentrancyGuard} or the
                         * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
                         */
                        function sendValue(address payable recipient, uint256 amount) internal {
                            require(address(this).balance >= amount, "Address: insufficient balance");
                            // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
                            (bool success, ) = recipient.call{ value: amount }("");
                            require(success, "Address: unable to send value, recipient may have reverted");
                        }
                        /**
                         * @dev Performs a Solidity function call using a low level `call`. A
                         * plain`call` is an unsafe replacement for a function call: use this
                         * function instead.
                         *
                         * If `target` reverts with a revert reason, it is bubbled up by this
                         * function (like regular Solidity function calls).
                         *
                         * Returns the raw returned data. To convert to the expected return value,
                         * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
                         *
                         * Requirements:
                         *
                         * - `target` must be a contract.
                         * - calling `target` with `data` must not revert.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                          return functionCall(target, data, "Address: low-level call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
                         * `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, 0, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but also transferring `value` wei to `target`.
                         *
                         * Requirements:
                         *
                         * - the calling contract must have an ETH balance of at least `value`.
                         * - the called Solidity function must be `payable`.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
                         * with `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
                            require(address(this).balance >= value, "Address: insufficient balance for call");
                            require(isContract(target), "Address: call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.call{ value: value }(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                            return functionStaticCall(target, data, "Address: low-level static call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
                            require(isContract(target), "Address: static call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.staticcall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                            return functionDelegateCall(target, data, "Address: low-level delegate call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a delegate call.
                         *
                         * _Available since v3.4._
                         */
                        function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            require(isContract(target), "Address: delegate call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.delegatecall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
                            if (success) {
                                return returndata;
                            } else {
                                // Look for revert reason and bubble it up if present
                                if (returndata.length > 0) {
                                    // The easiest way to bubble the revert reason is using memory via assembly
                                    // solhint-disable-next-line no-inline-assembly
                                    assembly {
                                        let returndata_size := mload(returndata)
                                        revert(add(32, returndata), returndata_size)
                                    }
                                } else {
                                    revert(errorMessage);
                                }
                            }
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "./Inbox.sol";
                    import "./Outbox.sol";
                    import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
                    import "@openzeppelin/contracts/utils/Address.sol";
                    import "./interfaces/IBridge.sol";
                    contract Bridge is OwnableUpgradeable, IBridge {
                        using Address for address;
                        struct InOutInfo {
                            uint256 index;
                            bool allowed;
                        }
                        mapping(address => InOutInfo) private allowedInboxesMap;
                        mapping(address => InOutInfo) private allowedOutboxesMap;
                        address[] public allowedInboxList;
                        address[] public allowedOutboxList;
                        address public override activeOutbox;
                        // Accumulator for delayed inbox; tail represents hash of the current state; each element represents the inclusion of a new message.
                        bytes32[] public override inboxAccs;
                        function initialize() external initializer {
                            __Ownable_init();
                        }
                        function allowedInboxes(address inbox) external view override returns (bool) {
                            return allowedInboxesMap[inbox].allowed;
                        }
                        function allowedOutboxes(address outbox) external view override returns (bool) {
                            return allowedOutboxesMap[outbox].allowed;
                        }
                        function deliverMessageToInbox(
                            uint8 kind,
                            address sender,
                            bytes32 messageDataHash
                        ) external payable override returns (uint256) {
                            require(allowedInboxesMap[msg.sender].allowed, "NOT_FROM_INBOX");
                            uint256 count = inboxAccs.length;
                            bytes32 messageHash =
                                Messages.messageHash(
                                    kind,
                                    sender,
                                    block.number,
                                    block.timestamp, // solhint-disable-line not-rely-on-time
                                    count,
                                    tx.gasprice,
                                    messageDataHash
                                );
                            bytes32 prevAcc = 0;
                            if (count > 0) {
                                prevAcc = inboxAccs[count - 1];
                            }
                            inboxAccs.push(Messages.addMessageToInbox(prevAcc, messageHash));
                            emit MessageDelivered(count, prevAcc, msg.sender, kind, sender, messageDataHash);
                            return count;
                        }
                        function executeCall(
                            address destAddr,
                            uint256 amount,
                            bytes calldata data
                        ) external override returns (bool success, bytes memory returnData) {
                            require(allowedOutboxesMap[msg.sender].allowed, "NOT_FROM_OUTBOX");
                            if (data.length > 0) require(destAddr.isContract(), "NO_CODE_AT_DEST");
                            address currentOutbox = activeOutbox;
                            activeOutbox = msg.sender;
                            // We set and reset active outbox around external call so activeOutbox remains valid during call
                            (success, returnData) = destAddr.call{ value: amount }(data);
                            activeOutbox = currentOutbox;
                            emit BridgeCallTriggered(msg.sender, destAddr, amount, data);
                        }
                        function setInbox(address inbox, bool enabled) external override onlyOwner {
                            InOutInfo storage info = allowedInboxesMap[inbox];
                            bool alreadyEnabled = info.allowed;
                            emit InboxToggle(inbox, enabled);
                            if ((alreadyEnabled && enabled) || (!alreadyEnabled && !enabled)) {
                                return;
                            }
                            if (enabled) {
                                allowedInboxesMap[inbox] = InOutInfo(allowedInboxList.length, true);
                                allowedInboxList.push(inbox);
                            } else {
                                allowedInboxList[info.index] = allowedInboxList[allowedInboxList.length - 1];
                                allowedInboxesMap[allowedInboxList[info.index]].index = info.index;
                                allowedInboxList.pop();
                                delete allowedInboxesMap[inbox];
                            }
                        }
                        function setOutbox(address outbox, bool enabled) external override onlyOwner {
                            InOutInfo storage info = allowedOutboxesMap[outbox];
                            bool alreadyEnabled = info.allowed;
                            emit OutboxToggle(outbox, enabled);
                            if ((alreadyEnabled && enabled) || (!alreadyEnabled && !enabled)) {
                                return;
                            }
                            if (enabled) {
                                allowedOutboxesMap[outbox] = InOutInfo(allowedOutboxList.length, true);
                                allowedOutboxList.push(outbox);
                            } else {
                                allowedOutboxList[info.index] = allowedOutboxList[allowedOutboxList.length - 1];
                                allowedOutboxesMap[allowedOutboxList[info.index]].index = info.index;
                                allowedOutboxList.pop();
                                delete allowedOutboxesMap[outbox];
                            }
                        }
                        function messageCount() external view override returns (uint256) {
                            return inboxAccs.length;
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface IMessageProvider {
                        event InboxMessageDelivered(uint256 indexed messageNum, bytes data);
                        event InboxMessageDeliveredFromOrigin(uint256 indexed messageNum);
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "./Context.sol";
                    /**
                     * @dev Contract module which allows children to implement an emergency stop
                     * mechanism that can be triggered by an authorized account.
                     *
                     * This module is used through inheritance. It will make available the
                     * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
                     * the functions of your contract. Note that they will not be pausable by
                     * simply including this module, only once the modifiers are put in place.
                     */
                    abstract contract Pausable is Context {
                        /**
                         * @dev Emitted when the pause is triggered by `account`.
                         */
                        event Paused(address account);
                        /**
                         * @dev Emitted when the pause is lifted by `account`.
                         */
                        event Unpaused(address account);
                        bool private _paused;
                        /**
                         * @dev Initializes the contract in unpaused state.
                         */
                        constructor () internal {
                            _paused = false;
                        }
                        /**
                         * @dev Returns true if the contract is paused, and false otherwise.
                         */
                        function paused() public view virtual returns (bool) {
                            return _paused;
                        }
                        /**
                         * @dev Modifier to make a function callable only when the contract is not paused.
                         *
                         * Requirements:
                         *
                         * - The contract must not be paused.
                         */
                        modifier whenNotPaused() {
                            require(!paused(), "Pausable: paused");
                            _;
                        }
                        /**
                         * @dev Modifier to make a function callable only when the contract is paused.
                         *
                         * Requirements:
                         *
                         * - The contract must be paused.
                         */
                        modifier whenPaused() {
                            require(paused(), "Pausable: not paused");
                            _;
                        }
                        /**
                         * @dev Triggers stopped state.
                         *
                         * Requirements:
                         *
                         * - The contract must not be paused.
                         */
                        function _pause() internal virtual whenNotPaused {
                            _paused = true;
                            emit Paused(_msgSender());
                        }
                        /**
                         * @dev Returns to normal state.
                         *
                         * Requirements:
                         *
                         * - The contract must be paused.
                         */
                        function _unpause() internal virtual whenPaused {
                            _paused = false;
                            emit Unpaused(_msgSender());
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /**
                     * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
                     * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
                     * be specified by overriding the virtual {_implementation} function.
                     *
                     * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
                     * different contract through the {_delegate} function.
                     *
                     * The success and return data of the delegated call will be returned back to the caller of the proxy.
                     */
                    abstract contract Proxy {
                        /**
                         * @dev Delegates the current call to `implementation`.
                         *
                         * This function does not return to its internall call site, it will return directly to the external caller.
                         */
                        function _delegate(address implementation) internal virtual {
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                // Copy msg.data. We take full control of memory in this inline assembly
                                // block because it will not return to Solidity code. We overwrite the
                                // Solidity scratch pad at memory position 0.
                                calldatacopy(0, 0, calldatasize())
                                // Call the implementation.
                                // out and outsize are 0 because we don't know the size yet.
                                let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)
                                // Copy the returned data.
                                returndatacopy(0, 0, returndatasize())
                                switch result
                                // delegatecall returns 0 on error.
                                case 0 { revert(0, returndatasize()) }
                                default { return(0, returndatasize()) }
                            }
                        }
                        /**
                         * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
                         * and {_fallback} should delegate.
                         */
                        function _implementation() internal view virtual returns (address);
                        /**
                         * @dev Delegates the current call to the address returned by `_implementation()`.
                         *
                         * This function does not return to its internall call site, it will return directly to the external caller.
                         */
                        function _fallback() internal virtual {
                            _beforeFallback();
                            _delegate(_implementation());
                        }
                        /**
                         * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
                         * function in the contract matches the call data.
                         */
                        fallback () external payable virtual {
                            _fallback();
                        }
                        /**
                         * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
                         * is empty.
                         */
                        receive () external payable virtual {
                            _fallback();
                        }
                        /**
                         * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
                         * call, or as part of the Solidity `fallback` or `receive` functions.
                         *
                         * If overriden should call `super._beforeFallback()`.
                         */
                        function _beforeFallback() internal virtual {
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /**
                     * @dev Interface of the ERC20 standard as defined in the EIP.
                     */
                    interface IERC20 {
                        /**
                         * @dev Returns the amount of tokens in existence.
                         */
                        function totalSupply() external view returns (uint256);
                        /**
                         * @dev Returns the amount of tokens owned by `account`.
                         */
                        function balanceOf(address account) external view returns (uint256);
                        /**
                         * @dev Moves `amount` tokens from the caller's account to `recipient`.
                         *
                         * Returns a boolean value indicating whether the operation succeeded.
                         *
                         * Emits a {Transfer} event.
                         */
                        function transfer(address recipient, uint256 amount) external returns (bool);
                        /**
                         * @dev Returns the remaining number of tokens that `spender` will be
                         * allowed to spend on behalf of `owner` through {transferFrom}. This is
                         * zero by default.
                         *
                         * This value changes when {approve} or {transferFrom} are called.
                         */
                        function allowance(address owner, address spender) external view returns (uint256);
                        /**
                         * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
                         *
                         * Returns a boolean value indicating whether the operation succeeded.
                         *
                         * IMPORTANT: Beware that changing an allowance with this method brings the risk
                         * that someone may use both the old and the new allowance by unfortunate
                         * transaction ordering. One possible solution to mitigate this race
                         * condition is to first reduce the spender's allowance to 0 and set the
                         * desired value afterwards:
                         * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
                         *
                         * Emits an {Approval} event.
                         */
                        function approve(address spender, uint256 amount) external returns (bool);
                        /**
                         * @dev Moves `amount` tokens from `sender` to `recipient` using the
                         * allowance mechanism. `amount` is then deducted from the caller's
                         * allowance.
                         *
                         * Returns a boolean value indicating whether the operation succeeded.
                         *
                         * Emits a {Transfer} event.
                         */
                        function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
                        /**
                         * @dev Emitted when `value` tokens are moved from one account (`from`) to
                         * another (`to`).
                         *
                         * Note that `value` may be zero.
                         */
                        event Transfer(address indexed from, address indexed to, uint256 value);
                        /**
                         * @dev Emitted when the allowance of a `spender` for an `owner` is set by
                         * a call to {approve}. `value` is the new allowance.
                         */
                        event Approval(address indexed owner, address indexed spender, uint256 value);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "./Rollup.sol";
                    import "./facets/IRollupFacets.sol";
                    import "../bridge/interfaces/IBridge.sol";
                    import "../bridge/interfaces/IMessageProvider.sol";
                    import "./INode.sol";
                    import "../libraries/Cloneable.sol";
                    contract RollupEventBridge is IMessageProvider, Cloneable {
                        uint8 internal constant INITIALIZATION_MSG_TYPE = 11;
                        uint8 internal constant ROLLUP_PROTOCOL_EVENT_TYPE = 8;
                        uint8 internal constant CREATE_NODE_EVENT = 0;
                        uint8 internal constant CONFIRM_NODE_EVENT = 1;
                        uint8 internal constant REJECT_NODE_EVENT = 2;
                        uint8 internal constant STAKE_CREATED_EVENT = 3;
                        IBridge bridge;
                        address rollup;
                        modifier onlyRollup() {
                            require(msg.sender == rollup, "ONLY_ROLLUP");
                            _;
                        }
                        function initialize(address _bridge, address _rollup) external {
                            require(rollup == address(0), "ALREADY_INIT");
                            bridge = IBridge(_bridge);
                            rollup = _rollup;
                        }
                        function rollupInitialized(
                            uint256 confirmPeriodBlocks,
                            uint256 avmGasSpeedLimitPerBlock,
                            address owner,
                            bytes calldata extraConfig
                        ) external onlyRollup {
                            bytes memory initMsg = abi.encodePacked(
                                keccak256("ChallengePeriodEthBlocks"),
                                confirmPeriodBlocks,
                                keccak256("SpeedLimitPerSecond"),
                                avmGasSpeedLimitPerBlock / 100, // convert avm gas to arbgas
                                keccak256("ChainOwner"),
                                uint256(uint160(bytes20(owner))),
                                extraConfig
                            );
                            uint256 num = bridge.deliverMessageToInbox(
                                INITIALIZATION_MSG_TYPE,
                                address(0),
                                keccak256(initMsg)
                            );
                            emit InboxMessageDelivered(num, initMsg);
                        }
                        function nodeCreated(
                            uint256 nodeNum,
                            uint256 prev,
                            uint256 deadline,
                            address asserter
                        ) external onlyRollup {
                            deliverToBridge(
                                abi.encodePacked(
                                    CREATE_NODE_EVENT,
                                    nodeNum,
                                    prev,
                                    block.number,
                                    deadline,
                                    uint256(uint160(bytes20(asserter)))
                                )
                            );
                        }
                        function nodeConfirmed(uint256 nodeNum) external onlyRollup {
                            deliverToBridge(abi.encodePacked(CONFIRM_NODE_EVENT, nodeNum));
                        }
                        function nodeRejected(uint256 nodeNum) external onlyRollup {
                            deliverToBridge(abi.encodePacked(REJECT_NODE_EVENT, nodeNum));
                        }
                        function stakeCreated(address staker, uint256 nodeNum) external onlyRollup {
                            deliverToBridge(
                                abi.encodePacked(
                                    STAKE_CREATED_EVENT,
                                    uint256(uint160(bytes20(staker))),
                                    nodeNum,
                                    block.number
                                )
                            );
                        }
                        function deliverToBridge(bytes memory message) private {
                            emit InboxMessageDelivered(
                                bridge.deliverMessageToInbox(
                                    ROLLUP_PROTOCOL_EVENT_TYPE,
                                    msg.sender,
                                    keccak256(message)
                                ),
                                message
                            );
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "./INode.sol";
                    import "./IRollupCore.sol";
                    import "./RollupLib.sol";
                    import "./INodeFactory.sol";
                    import "./RollupEventBridge.sol";
                    import "../bridge/interfaces/ISequencerInbox.sol";
                    import "@openzeppelin/contracts/math/SafeMath.sol";
                    contract RollupCore is IRollupCore {
                        using SafeMath for uint256;
                        // Stakers become Zombies after losing a challenge
                        struct Zombie {
                            address stakerAddress;
                            uint256 latestStakedNode;
                        }
                        struct Staker {
                            uint256 index;
                            uint256 latestStakedNode;
                            uint256 amountStaked;
                            // currentChallenge is 0 if staker is not in a challenge
                            address currentChallenge;
                            bool isStaked;
                        }
                        uint256 private _latestConfirmed;
                        uint256 private _firstUnresolvedNode;
                        uint256 private _latestNodeCreated;
                        uint256 private _lastStakeBlock;
                        mapping(uint256 => INode) private _nodes;
                        mapping(uint256 => bytes32) private _nodeHashes;
                        address payable[] private _stakerList;
                        mapping(address => Staker) public override _stakerMap;
                        Zombie[] private _zombies;
                        mapping(address => uint256) private _withdrawableFunds;
                        /**
                         * @notice Get the address of the Node contract for the given node
                         * @param nodeNum Index of the node
                         * @return Address of the Node contract
                         */
                        function getNode(uint256 nodeNum) public view override returns (INode) {
                            return _nodes[nodeNum];
                        }
                        /**
                         * @notice Get the address of the staker at the given index
                         * @param stakerNum Index of the staker
                         * @return Address of the staker
                         */
                        function getStakerAddress(uint256 stakerNum) external view override returns (address) {
                            return _stakerList[stakerNum];
                        }
                        /**
                         * @notice Check whether the given staker is staked
                         * @param staker Staker address to check
                         * @return True or False for whether the staker was staked
                         */
                        function isStaked(address staker) public view override returns (bool) {
                            return _stakerMap[staker].isStaked;
                        }
                        /**
                         * @notice Get the latest staked node of the given staker
                         * @param staker Staker address to lookup
                         * @return Latest node staked of the staker
                         */
                        function latestStakedNode(address staker) public view override returns (uint256) {
                            return _stakerMap[staker].latestStakedNode;
                        }
                        /**
                         * @notice Get the current challenge of the given staker
                         * @param staker Staker address to lookup
                         * @return Current challenge of the staker
                         */
                        function currentChallenge(address staker) public view override returns (address) {
                            return _stakerMap[staker].currentChallenge;
                        }
                        /**
                         * @notice Get the amount staked of the given staker
                         * @param staker Staker address to lookup
                         * @return Amount staked of the staker
                         */
                        function amountStaked(address staker) public view override returns (uint256) {
                            return _stakerMap[staker].amountStaked;
                        }
                        /**
                         * @notice Get the original staker address of the zombie at the given index
                         * @param zombieNum Index of the zombie to lookup
                         * @return Original staker address of the zombie
                         */
                        function zombieAddress(uint256 zombieNum) public view override returns (address) {
                            return _zombies[zombieNum].stakerAddress;
                        }
                        /**
                         * @notice Get Latest node that the given zombie at the given index is staked on
                         * @param zombieNum Index of the zombie to lookup
                         * @return Latest node that the given zombie is staked on
                         */
                        function zombieLatestStakedNode(uint256 zombieNum) public view override returns (uint256) {
                            return _zombies[zombieNum].latestStakedNode;
                        }
                        /// @return Current number of un-removed zombies
                        function zombieCount() public view override returns (uint256) {
                            return _zombies.length;
                        }
                        function isZombie(address staker) public view override returns (bool) {
                            for (uint256 i = 0; i < _zombies.length; i++) {
                                if (staker == _zombies[i].stakerAddress) {
                                    return true;
                                }
                            }
                            return false;
                        }
                        /**
                         * @notice Get the amount of funds withdrawable by the given address
                         * @param owner Address to check the funds of
                         * @return Amount of funds withdrawable by owner
                         */
                        function withdrawableFunds(address owner) external view override returns (uint256) {
                            return _withdrawableFunds[owner];
                        }
                        /**
                         * @return Index of the first unresolved node
                         * @dev If all nodes have been resolved, this will be latestNodeCreated + 1
                         */
                        function firstUnresolvedNode() public view override returns (uint256) {
                            return _firstUnresolvedNode;
                        }
                        /// @return Index of the latest confirmed node
                        function latestConfirmed() public view override returns (uint256) {
                            return _latestConfirmed;
                        }
                        /// @return Index of the latest rollup node created
                        function latestNodeCreated() public view override returns (uint256) {
                            return _latestNodeCreated;
                        }
                        /// @return Ethereum block that the most recent stake was created
                        function lastStakeBlock() external view override returns (uint256) {
                            return _lastStakeBlock;
                        }
                        /// @return Number of active stakers currently staked
                        function stakerCount() public view override returns (uint256) {
                            return _stakerList.length;
                        }
                        /**
                         * @notice Initialize the core with an initial node
                         * @param initialNode Initial node to start the chain with
                         */
                        function initializeCore(INode initialNode) internal {
                            _nodes[0] = initialNode;
                            _firstUnresolvedNode = 1;
                        }
                        /**
                         * @notice React to a new node being created by storing it an incrementing the latest node counter
                         * @param node Node that was newly created
                         * @param nodeHash The hash of said node
                         */
                        function nodeCreated(INode node, bytes32 nodeHash) internal {
                            _latestNodeCreated++;
                            _nodes[_latestNodeCreated] = node;
                            _nodeHashes[_latestNodeCreated] = nodeHash;
                        }
                        /// @return Node hash as of this node number
                        function getNodeHash(uint256 index) public view override returns (bytes32) {
                            return _nodeHashes[index];
                        }
                        /// @notice Reject the next unresolved node
                        function _rejectNextNode() internal {
                            destroyNode(_firstUnresolvedNode);
                            _firstUnresolvedNode++;
                        }
                        /// @notice Confirm the next unresolved node
                        function confirmNextNode(
                            bytes32 beforeSendAcc,
                            bytes calldata sendsData,
                            uint256[] calldata sendLengths,
                            uint256 afterSendCount,
                            bytes32 afterLogAcc,
                            uint256 afterLogCount,
                            IOutbox outbox,
                            RollupEventBridge rollupEventBridge
                        ) internal {
                            confirmNode(
                                _firstUnresolvedNode,
                                beforeSendAcc,
                                sendsData,
                                sendLengths,
                                afterSendCount,
                                afterLogAcc,
                                afterLogCount,
                                outbox,
                                rollupEventBridge
                            );
                        }
                        function confirmNode(
                            uint256 nodeNum,
                            bytes32 beforeSendAcc,
                            bytes calldata sendsData,
                            uint256[] calldata sendLengths,
                            uint256 afterSendCount,
                            bytes32 afterLogAcc,
                            uint256 afterLogCount,
                            IOutbox outbox,
                            RollupEventBridge rollupEventBridge
                        ) internal {
                            bytes32 afterSendAcc = RollupLib.feedAccumulator(sendsData, sendLengths, beforeSendAcc);
                            INode node = getNode(nodeNum);
                            // Authenticate data against node's confirm data pre-image
                            require(
                                node.confirmData() ==
                                    RollupLib.confirmHash(
                                        beforeSendAcc,
                                        afterSendAcc,
                                        afterLogAcc,
                                        afterSendCount,
                                        afterLogCount
                                    ),
                                "CONFIRM_DATA"
                            );
                            // trusted external call to outbox
                            outbox.processOutgoingMessages(sendsData, sendLengths);
                            destroyNode(_latestConfirmed);
                            _latestConfirmed = nodeNum;
                            _firstUnresolvedNode = nodeNum + 1;
                            rollupEventBridge.nodeConfirmed(nodeNum);
                            emit NodeConfirmed(nodeNum, afterSendAcc, afterSendCount, afterLogAcc, afterLogCount);
                        }
                        /**
                         * @notice Create a new stake at latest confirmed node
                         * @param stakerAddress Address of the new staker
                         * @param depositAmount Stake amount of the new staker
                         */
                        function createNewStake(address payable stakerAddress, uint256 depositAmount) internal {
                            uint256 stakerIndex = _stakerList.length;
                            _stakerList.push(stakerAddress);
                            _stakerMap[stakerAddress] = Staker(
                                stakerIndex,
                                _latestConfirmed,
                                depositAmount,
                                address(0), // new staker is not in challenge
                                true
                            );
                            _lastStakeBlock = block.number;
                            emit UserStakeUpdated(stakerAddress, 0, depositAmount);
                        }
                        /**
                         * @notice Check to see whether the two stakers are in the same challenge
                         * @param stakerAddress1 Address of the first staker
                         * @param stakerAddress2 Address of the second staker
                         * @return Address of the challenge that the two stakers are in
                         */
                        function inChallenge(address stakerAddress1, address stakerAddress2)
                            internal
                            view
                            returns (address)
                        {
                            Staker storage staker1 = _stakerMap[stakerAddress1];
                            Staker storage staker2 = _stakerMap[stakerAddress2];
                            address challenge = staker1.currentChallenge;
                            require(challenge != address(0), "NO_CHAL");
                            require(challenge == staker2.currentChallenge, "DIFF_IN_CHAL");
                            return challenge;
                        }
                        /**
                         * @notice Make the given staker as not being in a challenge
                         * @param stakerAddress Address of the staker to remove from a challenge
                         */
                        function clearChallenge(address stakerAddress) internal {
                            Staker storage staker = _stakerMap[stakerAddress];
                            staker.currentChallenge = address(0);
                        }
                        /**
                         * @notice Mark both the given stakers as engaged in the challenge
                         * @param staker1 Address of the first staker
                         * @param staker2 Address of the second staker
                         * @param challenge Address of the challenge both stakers are now in
                         */
                        function challengeStarted(
                            address staker1,
                            address staker2,
                            address challenge
                        ) internal {
                            _stakerMap[staker1].currentChallenge = challenge;
                            _stakerMap[staker2].currentChallenge = challenge;
                        }
                        /**
                         * @notice Add to the stake of the given staker by the given amount
                         * @param stakerAddress Address of the staker to increase the stake of
                         * @param amountAdded Amount of stake to add to the staker
                         */
                        function increaseStakeBy(address stakerAddress, uint256 amountAdded) internal {
                            Staker storage staker = _stakerMap[stakerAddress];
                            uint256 initialStaked = staker.amountStaked;
                            uint256 finalStaked = initialStaked.add(amountAdded);
                            staker.amountStaked = finalStaked;
                            emit UserStakeUpdated(stakerAddress, initialStaked, finalStaked);
                        }
                        /**
                         * @notice Reduce the stake of the given staker to the given target
                         * @param stakerAddress Address of the staker to reduce the stake of
                         * @param target Amount of stake to leave with the staker
                         * @return Amount of value released from the stake
                         */
                        function reduceStakeTo(address stakerAddress, uint256 target) internal returns (uint256) {
                            Staker storage staker = _stakerMap[stakerAddress];
                            uint256 current = staker.amountStaked;
                            require(target <= current, "TOO_LITTLE_STAKE");
                            uint256 amountWithdrawn = current.sub(target);
                            staker.amountStaked = target;
                            increaseWithdrawableFunds(stakerAddress, amountWithdrawn);
                            emit UserStakeUpdated(stakerAddress, current, target);
                            return amountWithdrawn;
                        }
                        /**
                         * @notice Remove the given staker and turn them into a zombie
                         * @param stakerAddress Address of the staker to remove
                         */
                        function turnIntoZombie(address stakerAddress) internal {
                            Staker storage staker = _stakerMap[stakerAddress];
                            _zombies.push(Zombie(stakerAddress, staker.latestStakedNode));
                            deleteStaker(stakerAddress);
                        }
                        /**
                         * @notice Update the latest staked node of the zombie at the given index
                         * @param zombieNum Index of the zombie to move
                         * @param latest New latest node the zombie is staked on
                         */
                        function zombieUpdateLatestStakedNode(uint256 zombieNum, uint256 latest) internal {
                            _zombies[zombieNum].latestStakedNode = latest;
                        }
                        /**
                         * @notice Remove the zombie at the given index
                         * @param zombieNum Index of the zombie to remove
                         */
                        function removeZombie(uint256 zombieNum) internal {
                            _zombies[zombieNum] = _zombies[_zombies.length - 1];
                            _zombies.pop();
                        }
                        /**
                         * @notice Remove the given staker and return their stake
                         * @param stakerAddress Address of the staker withdrawing their stake
                         */
                        function withdrawStaker(address stakerAddress) internal {
                            Staker storage staker = _stakerMap[stakerAddress];
                            uint256 initialStaked = staker.amountStaked;
                            increaseWithdrawableFunds(stakerAddress, initialStaked);
                            deleteStaker(stakerAddress);
                            emit UserStakeUpdated(stakerAddress, initialStaked, 0);
                        }
                        /**
                         * @notice Advance the given staker to the given node
                         * @param stakerAddress Address of the staker adding their stake
                         * @param nodeNum Index of the node to stake on
                         */
                        function stakeOnNode(
                            address stakerAddress,
                            uint256 nodeNum,
                            uint256 confirmPeriodBlocks
                        ) internal {
                            Staker storage staker = _stakerMap[stakerAddress];
                            INode node = _nodes[nodeNum];
                            uint256 newStakerCount = node.addStaker(stakerAddress);
                            staker.latestStakedNode = nodeNum;
                            if (newStakerCount == 1) {
                                INode parent = _nodes[node.prev()];
                                parent.newChildConfirmDeadline(block.number.add(confirmPeriodBlocks));
                            }
                        }
                        /**
                         * @notice Clear the withdrawable funds for the given address
                         * @param owner Address of the account to remove funds from
                         * @return Amount of funds removed from account
                         */
                        function withdrawFunds(address owner) internal returns (uint256) {
                            uint256 amount = _withdrawableFunds[owner];
                            _withdrawableFunds[owner] = 0;
                            emit UserWithdrawableFundsUpdated(owner, amount, 0);
                            return amount;
                        }
                        /**
                         * @notice Increase the withdrawable funds for the given address
                         * @param owner Address of the account to add withdrawable funds to
                         */
                        function increaseWithdrawableFunds(address owner, uint256 amount) internal {
                            uint256 initialWithdrawable = _withdrawableFunds[owner];
                            uint256 finalWithdrawable = initialWithdrawable.add(amount);
                            _withdrawableFunds[owner] = finalWithdrawable;
                            emit UserWithdrawableFundsUpdated(owner, initialWithdrawable, finalWithdrawable);
                        }
                        /**
                         * @notice Remove the given staker
                         * @param stakerAddress Address of the staker to remove
                         */
                        function deleteStaker(address stakerAddress) private {
                            Staker storage staker = _stakerMap[stakerAddress];
                            uint256 stakerIndex = staker.index;
                            _stakerList[stakerIndex] = _stakerList[_stakerList.length - 1];
                            _stakerMap[_stakerList[stakerIndex]].index = stakerIndex;
                            _stakerList.pop();
                            delete _stakerMap[stakerAddress];
                        }
                        /**
                         * @notice Destroy the given node and clear out its address
                         * @param nodeNum Index of the node to remove
                         */
                        function destroyNode(uint256 nodeNum) internal {
                            _nodes[nodeNum].destroy();
                            _nodes[nodeNum] = INode(0);
                        }
                        function nodeDeadline(
                            uint256 avmGasSpeedLimitPerBlock,
                            uint256 gasUsed,
                            uint256 confirmPeriodBlocks,
                            INode prevNode
                        ) internal view returns (uint256 deadlineBlock) {
                            // Set deadline rounding up to the nearest block
                            uint256 checkTime =
                                gasUsed.add(avmGasSpeedLimitPerBlock.sub(1)).div(avmGasSpeedLimitPerBlock);
                            deadlineBlock = max(block.number.add(confirmPeriodBlocks), prevNode.deadlineBlock()).add(
                                checkTime
                            );
                            uint256 olderSibling = prevNode.latestChildNumber();
                            if (olderSibling != 0) {
                                deadlineBlock = max(deadlineBlock, getNode(olderSibling).deadlineBlock());
                            }
                            return deadlineBlock;
                        }
                        function max(uint256 a, uint256 b) internal pure returns (uint256) {
                            return a > b ? a : b;
                        }
                        struct StakeOnNewNodeFrame {
                            uint256 currentInboxSize;
                            INode node;
                            bytes32 executionHash;
                            INode prevNode;
                            bytes32 lastHash;
                            bool hasSibling;
                            uint256 deadlineBlock;
                            uint256 gasUsed;
                            uint256 sequencerBatchEnd;
                            bytes32 sequencerBatchAcc;
                        }
                        struct CreateNodeDataFrame {
                            uint256 prevNode;
                            uint256 confirmPeriodBlocks;
                            uint256 avmGasSpeedLimitPerBlock;
                            ISequencerInbox sequencerInbox;
                            RollupEventBridge rollupEventBridge;
                            INodeFactory nodeFactory;
                        }
                        uint8 internal constant MAX_SEND_COUNT = 100;
                        function createNewNode(
                            RollupLib.Assertion memory assertion,
                            bytes32[3][2] calldata assertionBytes32Fields,
                            uint256[4][2] calldata assertionIntFields,
                            bytes calldata sequencerBatchProof,
                            CreateNodeDataFrame memory inputDataFrame,
                            bytes32 expectedNodeHash
                        ) internal returns (bytes32 newNodeHash) {
                            StakeOnNewNodeFrame memory memoryFrame;
                            {
                                // validate data
                                memoryFrame.gasUsed = RollupLib.assertionGasUsed(assertion);
                                memoryFrame.prevNode = getNode(inputDataFrame.prevNode);
                                memoryFrame.currentInboxSize = inputDataFrame.sequencerInbox.messageCount();
                                // Make sure the previous state is correct against the node being built on
                                require(
                                    RollupLib.stateHash(assertion.beforeState) == memoryFrame.prevNode.stateHash(),
                                    "PREV_STATE_HASH"
                                );
                                // Ensure that the assertion doesn't read past the end of the current inbox
                                require(
                                    assertion.afterState.inboxCount <= memoryFrame.currentInboxSize,
                                    "INBOX_PAST_END"
                                );
                                // Insure inbox tip after assertion is included in a sequencer-inbox batch and return inbox acc; this gives replay protection against the state of the inbox
                                (memoryFrame.sequencerBatchEnd, memoryFrame.sequencerBatchAcc) = inputDataFrame
                                    .sequencerInbox
                                    .proveInboxContainsMessage(sequencerBatchProof, assertion.afterState.inboxCount);
                            }
                            {
                                memoryFrame.executionHash = RollupLib.executionHash(assertion);
                                memoryFrame.deadlineBlock = nodeDeadline(
                                    inputDataFrame.avmGasSpeedLimitPerBlock,
                                    memoryFrame.gasUsed,
                                    inputDataFrame.confirmPeriodBlocks,
                                    memoryFrame.prevNode
                                );
                                memoryFrame.hasSibling = memoryFrame.prevNode.latestChildNumber() > 0;
                                // here we don't use ternacy operator to remain compatible with slither
                                if (memoryFrame.hasSibling) {
                                    memoryFrame.lastHash = getNodeHash(memoryFrame.prevNode.latestChildNumber());
                                } else {
                                    memoryFrame.lastHash = getNodeHash(inputDataFrame.prevNode);
                                }
                                memoryFrame.node = INode(
                                    inputDataFrame.nodeFactory.createNode(
                                        RollupLib.stateHash(assertion.afterState),
                                        RollupLib.challengeRoot(assertion, memoryFrame.executionHash, block.number),
                                        RollupLib.confirmHash(assertion),
                                        inputDataFrame.prevNode,
                                        memoryFrame.deadlineBlock
                                    )
                                );
                            }
                            {
                                uint256 nodeNum = latestNodeCreated() + 1;
                                memoryFrame.prevNode.childCreated(nodeNum);
                                newNodeHash = RollupLib.nodeHash(
                                    memoryFrame.hasSibling,
                                    memoryFrame.lastHash,
                                    memoryFrame.executionHash,
                                    memoryFrame.sequencerBatchAcc
                                );
                                require(newNodeHash == expectedNodeHash, "UNEXPECTED_NODE_HASH");
                                nodeCreated(memoryFrame.node, newNodeHash);
                                inputDataFrame.rollupEventBridge.nodeCreated(
                                    nodeNum,
                                    inputDataFrame.prevNode,
                                    memoryFrame.deadlineBlock,
                                    msg.sender
                                );
                            }
                            emit NodeCreated(
                                latestNodeCreated(),
                                getNodeHash(inputDataFrame.prevNode),
                                newNodeHash,
                                memoryFrame.executionHash,
                                memoryFrame.currentInboxSize,
                                memoryFrame.sequencerBatchEnd,
                                memoryFrame.sequencerBatchAcc,
                                assertionBytes32Fields,
                                assertionIntFields
                            );
                            return newNodeHash;
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "../challenge/ChallengeLib.sol";
                    import "./INode.sol";
                    import "@openzeppelin/contracts/math/SafeMath.sol";
                    library RollupLib {
                        using SafeMath for uint256;
                        struct Config {
                            bytes32 machineHash;
                            uint256 confirmPeriodBlocks;
                            uint256 extraChallengeTimeBlocks;
                            uint256 avmGasSpeedLimitPerBlock;
                            uint256 baseStake;
                            address stakeToken;
                            address owner;
                            address sequencer;
                            uint256 sequencerDelayBlocks;
                            uint256 sequencerDelaySeconds;
                            bytes extraConfig;
                        }
                        struct ExecutionState {
                            uint256 gasUsed;
                            bytes32 machineHash;
                            uint256 inboxCount;
                            uint256 sendCount;
                            uint256 logCount;
                            bytes32 sendAcc;
                            bytes32 logAcc;
                            uint256 proposedBlock;
                            uint256 inboxMaxCount;
                        }
                        function stateHash(ExecutionState memory execState) internal pure returns (bytes32) {
                            return
                                keccak256(
                                    abi.encodePacked(
                                        execState.gasUsed,
                                        execState.machineHash,
                                        execState.inboxCount,
                                        execState.sendCount,
                                        execState.logCount,
                                        execState.sendAcc,
                                        execState.logAcc,
                                        execState.proposedBlock,
                                        execState.inboxMaxCount
                                    )
                                );
                        }
                        struct Assertion {
                            ExecutionState beforeState;
                            ExecutionState afterState;
                        }
                        function decodeExecutionState(
                            bytes32[3] memory bytes32Fields,
                            uint256[4] memory intFields,
                            uint256 proposedBlock,
                            uint256 inboxMaxCount
                        ) internal pure returns (ExecutionState memory) {
                            return
                                ExecutionState(
                                    intFields[0],
                                    bytes32Fields[0],
                                    intFields[1],
                                    intFields[2],
                                    intFields[3],
                                    bytes32Fields[1],
                                    bytes32Fields[2],
                                    proposedBlock,
                                    inboxMaxCount
                                );
                        }
                        function decodeAssertion(
                            bytes32[3][2] memory bytes32Fields,
                            uint256[4][2] memory intFields,
                            uint256 beforeProposedBlock,
                            uint256 beforeInboxMaxCount,
                            uint256 inboxMaxCount
                        ) internal view returns (Assertion memory) {
                            return
                                Assertion(
                                    decodeExecutionState(
                                        bytes32Fields[0],
                                        intFields[0],
                                        beforeProposedBlock,
                                        beforeInboxMaxCount
                                    ),
                                    decodeExecutionState(bytes32Fields[1], intFields[1], block.number, inboxMaxCount)
                                );
                        }
                        function executionStateChallengeHash(ExecutionState memory state)
                            internal
                            pure
                            returns (bytes32)
                        {
                            return
                                ChallengeLib.assertionHash(
                                    state.gasUsed,
                                    ChallengeLib.assertionRestHash(
                                        state.inboxCount,
                                        state.machineHash,
                                        state.sendAcc,
                                        state.sendCount,
                                        state.logAcc,
                                        state.logCount
                                    )
                                );
                        }
                        function executionHash(Assertion memory assertion) internal pure returns (bytes32) {
                            return
                                ChallengeLib.bisectionChunkHash(
                                    assertion.beforeState.gasUsed,
                                    assertion.afterState.gasUsed - assertion.beforeState.gasUsed,
                                    RollupLib.executionStateChallengeHash(assertion.beforeState),
                                    RollupLib.executionStateChallengeHash(assertion.afterState)
                                );
                        }
                        function assertionGasUsed(RollupLib.Assertion memory assertion)
                            internal
                            pure
                            returns (uint256)
                        {
                            return assertion.afterState.gasUsed.sub(assertion.beforeState.gasUsed);
                        }
                        function challengeRoot(
                            Assertion memory assertion,
                            bytes32 assertionExecHash,
                            uint256 blockProposed
                        ) internal pure returns (bytes32) {
                            return challengeRootHash(assertionExecHash, blockProposed, assertion.afterState.inboxCount);
                        }
                        function challengeRootHash(
                            bytes32 execution,
                            uint256 proposedTime,
                            uint256 maxMessageCount
                        ) internal pure returns (bytes32) {
                            return keccak256(abi.encodePacked(execution, proposedTime, maxMessageCount));
                        }
                        function confirmHash(Assertion memory assertion) internal pure returns (bytes32) {
                            return
                                confirmHash(
                                    assertion.beforeState.sendAcc,
                                    assertion.afterState.sendAcc,
                                    assertion.afterState.logAcc,
                                    assertion.afterState.sendCount,
                                    assertion.afterState.logCount
                                );
                        }
                        function confirmHash(
                            bytes32 beforeSendAcc,
                            bytes32 afterSendAcc,
                            bytes32 afterLogAcc,
                            uint256 afterSendCount,
                            uint256 afterLogCount
                        ) internal pure returns (bytes32) {
                            return
                                keccak256(
                                    abi.encodePacked(
                                        beforeSendAcc,
                                        afterSendAcc,
                                        afterSendCount,
                                        afterLogAcc,
                                        afterLogCount
                                    )
                                );
                        }
                        function feedAccumulator(
                            bytes memory messageData,
                            uint256[] memory messageLengths,
                            bytes32 beforeAcc
                        ) internal pure returns (bytes32) {
                            uint256 offset = 0;
                            uint256 messageCount = messageLengths.length;
                            uint256 dataLength = messageData.length;
                            bytes32 messageAcc = beforeAcc;
                            for (uint256 i = 0; i < messageCount; i++) {
                                uint256 messageLength = messageLengths[i];
                                require(offset + messageLength <= dataLength, "DATA_OVERRUN");
                                bytes32 messageHash;
                                assembly {
                                    messageHash := keccak256(add(messageData, add(offset, 32)), messageLength)
                                }
                                messageAcc = keccak256(abi.encodePacked(messageAcc, messageHash));
                                offset += messageLength;
                            }
                            require(offset == dataLength, "DATA_LENGTH");
                            return messageAcc;
                        }
                        function nodeHash(
                            bool hasSibling,
                            bytes32 lastHash,
                            bytes32 assertionExecHash,
                            bytes32 inboxAcc
                        ) internal pure returns (bytes32) {
                            uint8 hasSiblingInt = hasSibling ? 1 : 0;
                            return keccak256(abi.encodePacked(hasSiblingInt, lastHash, assertionExecHash, inboxAcc));
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface INode {
                        function initialize(
                            address _rollup,
                            bytes32 _stateHash,
                            bytes32 _challengeHash,
                            bytes32 _confirmData,
                            uint256 _prev,
                            uint256 _deadlineBlock
                        ) external;
                        function destroy() external;
                        function addStaker(address staker) external returns (uint256);
                        function removeStaker(address staker) external;
                        function childCreated(uint256) external;
                        function newChildConfirmDeadline(uint256 deadline) external;
                        function stateHash() external view returns (bytes32);
                        function challengeHash() external view returns (bytes32);
                        function confirmData() external view returns (bytes32);
                        function prev() external view returns (uint256);
                        function deadlineBlock() external view returns (uint256);
                        function noChildConfirmedBeforeBlock() external view returns (uint256);
                        function stakerCount() external view returns (uint256);
                        function stakers(address staker) external view returns (bool);
                        function firstChildBlock() external view returns (uint256);
                        function latestChildNumber() external view returns (uint256);
                        function requirePastDeadline() external view;
                        function requirePastChildConfirmDeadline() external view;
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface INodeFactory {
                        function createNode(
                            bytes32 _stateHash,
                            bytes32 _challengeHash,
                            bytes32 _confirmData,
                            uint256 _prev,
                            uint256 _deadlineBlock
                        ) external returns (address);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "../bridge/interfaces/IBridge.sol";
                    import "../bridge/interfaces/ISequencerInbox.sol";
                    import "../arch/IOneStepProof.sol";
                    interface IChallenge {
                        function initializeChallenge(
                            IOneStepProof[] calldata _executors,
                            address _resultReceiver,
                            bytes32 _executionHash,
                            uint256 _maxMessageCount,
                            address _asserter,
                            address _challenger,
                            uint256 _asserterTimeLeft,
                            uint256 _challengerTimeLeft,
                            ISequencerInbox _sequencerBridge,
                            IBridge _delayedBridge
                        ) external;
                        function currentResponderTimeLeft() external view returns (uint256);
                        function lastMoveBlock() external view returns (uint256);
                        function timeout() external;
                        function asserter() external view returns (address);
                        function challenger() external view returns (address);
                        function clearChallenge() external;
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2019-2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "../bridge/interfaces/IBridge.sol";
                    import "../bridge/interfaces/ISequencerInbox.sol";
                    interface IChallengeFactory {
                        function createChallenge(
                            address _resultReceiver,
                            bytes32 _executionHash,
                            uint256 _maxMessageCount,
                            address _asserter,
                            address _challenger,
                            uint256 _asserterTimeLeft,
                            uint256 _challengerTimeLeft,
                            ISequencerInbox _sequencerBridge,
                            IBridge _delayedBridge
                        ) external returns (address);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface IOutbox {
                        event OutboxEntryCreated(
                            uint256 indexed batchNum,
                            uint256 outboxEntryIndex,
                            bytes32 outputRoot,
                            uint256 numInBatch
                        );
                        event OutBoxTransactionExecuted(
                            address indexed destAddr,
                            address indexed l2Sender,
                            uint256 indexed outboxEntryIndex,
                            uint256 transactionIndex
                        );
                        function l2ToL1Sender() external view returns (address);
                        function l2ToL1Block() external view returns (uint256);
                        function l2ToL1EthBlock() external view returns (uint256);
                        function l2ToL1Timestamp() external view returns (uint256);
                        function l2ToL1BatchNum() external view returns (uint256);
                        function l2ToL1OutputId() external view returns (bytes32);
                        function processOutgoingMessages(bytes calldata sendsData, uint256[] calldata sendLengths)
                            external;
                        function outboxEntryExists(uint256 batchNum) external view returns (bool);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "../INode.sol";
                    import "../../bridge/interfaces/IOutbox.sol";
                    interface IRollupUser {
                        function initialize(address _stakeToken) external;
                        function completeChallenge(address winningStaker, address losingStaker) external;
                        function returnOldDeposit(address stakerAddress) external;
                        function requireUnresolved(uint256 nodeNum) external view;
                        function requireUnresolvedExists() external view;
                        function countStakedZombies(INode node) external view returns (uint256);
                    }
                    interface IRollupAdmin {
                        event OwnerFunctionCalled(uint256 indexed id);
                        /**
                         * @notice Add a contract authorized to put messages into this rollup's inbox
                         * @param _outbox Outbox contract to add
                         */
                        function setOutbox(IOutbox _outbox) external;
                        /**
                         * @notice Disable an old outbox from interacting with the bridge
                         * @param _outbox Outbox contract to remove
                         */
                        function removeOldOutbox(address _outbox) external;
                        /**
                         * @notice Enable or disable an inbox contract
                         * @param _inbox Inbox contract to add or remove
                         * @param _enabled New status of inbox
                         */
                        function setInbox(address _inbox, bool _enabled) external;
                        /**
                         * @notice Pause interaction with the rollup contract
                         */
                        function pause() external;
                        /**
                         * @notice Resume interaction with the rollup contract
                         */
                        function resume() external;
                        /**
                         * @notice Set the addresses of rollup logic facets called
                         * @param newAdminFacet address of logic that owner of rollup calls
                         * @param newUserFacet ddress of logic that user of rollup calls
                         */
                        function setFacets(address newAdminFacet, address newUserFacet) external;
                        /**
                         * @notice Set the addresses of the validator whitelist
                         * @dev It is expected that both arrays are same length, and validator at
                         * position i corresponds to the value at position i
                         * @param _validator addresses to set in the whitelist
                         * @param _val value to set in the whitelist for corresponding address
                         */
                        function setValidator(address[] memory _validator, bool[] memory _val) external;
                        /**
                         * @notice Set a new owner address for the rollup
                         * @param newOwner address of new rollup owner
                         */
                        function setOwner(address newOwner) external;
                        /**
                         * @notice Set minimum assertion period for the rollup
                         * @param newPeriod new minimum period for assertions
                         */
                        function setMinimumAssertionPeriod(uint256 newPeriod) external;
                        /**
                         * @notice Set number of blocks until a node is considered confirmed
                         * @param newConfirmPeriod new number of blocks until a node is confirmed
                         */
                        function setConfirmPeriodBlocks(uint256 newConfirmPeriod) external;
                        /**
                         * @notice Set number of extra blocks after a challenge
                         * @param newExtraTimeBlocks new number of blocks
                         */
                        function setExtraChallengeTimeBlocks(uint256 newExtraTimeBlocks) external;
                        /**
                         * @notice Set speed limit per block
                         * @param newAvmGasSpeedLimitPerBlock maximum avmgas to be used per block
                         */
                        function setAvmGasSpeedLimitPerBlock(uint256 newAvmGasSpeedLimitPerBlock) external;
                        /**
                         * @notice Set base stake required for an assertion
                         * @param newBaseStake maximum avmgas to be used per block
                         */
                        function setBaseStake(uint256 newBaseStake) external;
                        /**
                         * @notice Set the token used for stake, where address(0) == eth
                         * @dev Before changing the base stake token, you might need to change the
                         * implementation of the Rollup User facet!
                         * @param newStakeToken address of token used for staking
                         */
                        function setStakeToken(address newStakeToken) external;
                        /**
                         * @notice Set max delay for sequencer inbox
                         * @param newSequencerInboxMaxDelayBlocks max number of blocks
                         * @param newSequencerInboxMaxDelaySeconds max number of seconds
                         */
                        function setSequencerInboxMaxDelay(
                            uint256 newSequencerInboxMaxDelayBlocks,
                            uint256 newSequencerInboxMaxDelaySeconds
                        ) external;
                        /**
                         * @notice Set execution bisection degree
                         * @param newChallengeExecutionBisectionDegree execution bisection degree
                         */
                        function setChallengeExecutionBisectionDegree(uint256 newChallengeExecutionBisectionDegree)
                            external;
                        /**
                         * @notice Updates a whitelist address for its consumers
                         * @dev setting the newWhitelist to address(0) disables it for consumers
                         * @param whitelist old whitelist to be deprecated
                         * @param newWhitelist new whitelist to be used
                         * @param targets whitelist consumers to be triggered
                         */
                        function updateWhitelistConsumers(
                            address whitelist,
                            address newWhitelist,
                            address[] memory targets
                        ) external;
                        /**
                         * @notice Updates a whitelist's entries
                         * @dev user at position i will be assigned value i
                         * @param whitelist whitelist to be updated
                         * @param user users to be updated in the whitelist
                         * @param val if user is or not allowed in the whitelist
                         */
                        function setWhitelistEntries(
                            address whitelist,
                            address[] memory user,
                            bool[] memory val
                        ) external;
                        /**
                         * @notice Updates whether an address is a sequencer at the sequencer inbox
                         * @param newSequencer address to be modified
                         * @param isSequencer whether this address should be authorized as a sequencer
                         */
                        function setIsSequencer(address newSequencer, bool isSequencer) external;
                        /**
                         * @notice Upgrades the implementation of a beacon controlled by the rollup
                         * @param beacon address of beacon to be upgraded
                         * @param newImplementation new address of implementation
                         */
                        function upgradeBeacon(address beacon, address newImplementation) external;
                        function forceResolveChallenge(address[] memory stackerA, address[] memory stackerB) external;
                        function forceRefundStaker(address[] memory stacker) external;
                        function forceCreateNode(
                            bytes32 expectedNodeHash,
                            bytes32[3][2] calldata assertionBytes32Fields,
                            uint256[4][2] calldata assertionIntFields,
                            bytes calldata sequencerBatchProof,
                            uint256 beforeProposedBlock,
                            uint256 beforeInboxMaxCount,
                            uint256 prevNode
                        ) external;
                        function forceConfirmNode(
                            uint256 nodeNum,
                            bytes32 beforeSendAcc,
                            bytes calldata sendsData,
                            uint256[] calldata sendLengths,
                            uint256 afterSendCount,
                            bytes32 afterLogAcc,
                            uint256 afterLogCount
                        ) external;
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /*
                     * @dev Provides information about the current execution context, including the
                     * sender of the transaction and its data. While these are generally available
                     * via msg.sender and msg.data, they should not be accessed in such a direct
                     * manner, since when dealing with GSN meta-transactions the account sending and
                     * paying for execution may not be the actual sender (as far as an application
                     * is concerned).
                     *
                     * This contract is only required for intermediate, library-like contracts.
                     */
                    abstract contract Context {
                        function _msgSender() internal view virtual returns (address payable) {
                            return msg.sender;
                        }
                        function _msgData() internal view virtual returns (bytes memory) {
                            this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
                            return msg.data;
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "./INode.sol";
                    interface IRollupCore {
                        function _stakerMap(address stakerAddress)
                            external
                            view
                            returns (
                                uint256,
                                uint256,
                                uint256,
                                address,
                                bool
                            );
                        event RollupCreated(bytes32 machineHash);
                        event NodeCreated(
                            uint256 indexed nodeNum,
                            bytes32 indexed parentNodeHash,
                            bytes32 nodeHash,
                            bytes32 executionHash,
                            uint256 inboxMaxCount,
                            uint256 afterInboxBatchEndCount,
                            bytes32 afterInboxBatchAcc,
                            bytes32[3][2] assertionBytes32Fields,
                            uint256[4][2] assertionIntFields
                        );
                        event NodeConfirmed(
                            uint256 indexed nodeNum,
                            bytes32 afterSendAcc,
                            uint256 afterSendCount,
                            bytes32 afterLogAcc,
                            uint256 afterLogCount
                        );
                        event NodeRejected(uint256 indexed nodeNum);
                        event RollupChallengeStarted(
                            address indexed challengeContract,
                            address asserter,
                            address challenger,
                            uint256 challengedNode
                        );
                        event UserStakeUpdated(address indexed user, uint256 initialBalance, uint256 finalBalance);
                        event UserWithdrawableFundsUpdated(
                            address indexed user,
                            uint256 initialBalance,
                            uint256 finalBalance
                        );
                        function getNode(uint256 nodeNum) external view returns (INode);
                        /**
                         * @notice Get the address of the staker at the given index
                         * @param stakerNum Index of the staker
                         * @return Address of the staker
                         */
                        function getStakerAddress(uint256 stakerNum) external view returns (address);
                        /**
                         * @notice Check whether the given staker is staked
                         * @param staker Staker address to check
                         * @return True or False for whether the staker was staked
                         */
                        function isStaked(address staker) external view returns (bool);
                        /**
                         * @notice Get the latest staked node of the given staker
                         * @param staker Staker address to lookup
                         * @return Latest node staked of the staker
                         */
                        function latestStakedNode(address staker) external view returns (uint256);
                        /**
                         * @notice Get the current challenge of the given staker
                         * @param staker Staker address to lookup
                         * @return Current challenge of the staker
                         */
                        function currentChallenge(address staker) external view returns (address);
                        /**
                         * @notice Get the amount staked of the given staker
                         * @param staker Staker address to lookup
                         * @return Amount staked of the staker
                         */
                        function amountStaked(address staker) external view returns (uint256);
                        /**
                         * @notice Get the original staker address of the zombie at the given index
                         * @param zombieNum Index of the zombie to lookup
                         * @return Original staker address of the zombie
                         */
                        function zombieAddress(uint256 zombieNum) external view returns (address);
                        /**
                         * @notice Get Latest node that the given zombie at the given index is staked on
                         * @param zombieNum Index of the zombie to lookup
                         * @return Latest node that the given zombie is staked on
                         */
                        function zombieLatestStakedNode(uint256 zombieNum) external view returns (uint256);
                        /// @return Current number of un-removed zombies
                        function zombieCount() external view returns (uint256);
                        function isZombie(address staker) external view returns (bool);
                        /**
                         * @notice Get the amount of funds withdrawable by the given address
                         * @param owner Address to check the funds of
                         * @return Amount of funds withdrawable by owner
                         */
                        function withdrawableFunds(address owner) external view returns (uint256);
                        /**
                         * @return Index of the first unresolved node
                         * @dev If all nodes have been resolved, this will be latestNodeCreated + 1
                         */
                        function firstUnresolvedNode() external view returns (uint256);
                        /// @return Index of the latest confirmed node
                        function latestConfirmed() external view returns (uint256);
                        /// @return Index of the latest rollup node created
                        function latestNodeCreated() external view returns (uint256);
                        /// @return Ethereum block that the most recent stake was created
                        function lastStakeBlock() external view returns (uint256);
                        /// @return Number of active stakers currently staked
                        function stakerCount() external view returns (uint256);
                        /// @return Node hash as of this node number
                        function getNodeHash(uint256 index) external view returns (bytes32);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface ISequencerInbox {
                        event SequencerBatchDelivered(
                            uint256 indexed firstMessageNum,
                            bytes32 indexed beforeAcc,
                            uint256 newMessageCount,
                            bytes32 afterAcc,
                            bytes transactions,
                            uint256[] lengths,
                            uint256[] sectionsMetadata,
                            uint256 seqBatchIndex,
                            address sequencer
                        );
                        event SequencerBatchDeliveredFromOrigin(
                            uint256 indexed firstMessageNum,
                            bytes32 indexed beforeAcc,
                            uint256 newMessageCount,
                            bytes32 afterAcc,
                            uint256 seqBatchIndex
                        );
                        event DelayedInboxForced(
                            uint256 indexed firstMessageNum,
                            bytes32 indexed beforeAcc,
                            uint256 newMessageCount,
                            uint256 totalDelayedMessagesRead,
                            bytes32[2] afterAccAndDelayed,
                            uint256 seqBatchIndex
                        );
                        /// @notice DEPRECATED - look at IsSequencerUpdated for new updates
                        // event SequencerAddressUpdated(address newAddress);
                        event IsSequencerUpdated(address addr, bool isSequencer);
                        event MaxDelayUpdated(uint256 newMaxDelayBlocks, uint256 newMaxDelaySeconds);
                        /// @notice DEPRECATED - look at MaxDelayUpdated for new updates
                        // event MaxDelayBlocksUpdated(uint256 newValue);
                        /// @notice DEPRECATED - look at MaxDelayUpdated for new updates
                        // event MaxDelaySecondsUpdated(uint256 newValue);
                        function setMaxDelay(uint256 newMaxDelayBlocks, uint256 newMaxDelaySeconds) external;
                        function setIsSequencer(address addr, bool isSequencer) external;
                        function messageCount() external view returns (uint256);
                        function maxDelayBlocks() external view returns (uint256);
                        function maxDelaySeconds() external view returns (uint256);
                        function inboxAccs(uint256 index) external view returns (bytes32);
                        function getInboxAccsLength() external view returns (uint256);
                        function proveInboxContainsMessage(bytes calldata proof, uint256 inboxCount)
                            external
                            view
                            returns (uint256, bytes32);
                        /// @notice DEPRECATED - use isSequencer instead
                        function sequencer() external view returns (address);
                        function isSequencer(address seq) external view returns (bool);
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /**
                     * @dev Wrappers over Solidity's arithmetic operations with added overflow
                     * checks.
                     *
                     * Arithmetic operations in Solidity wrap on overflow. This can easily result
                     * in bugs, because programmers usually assume that an overflow raises an
                     * error, which is the standard behavior in high level programming languages.
                     * `SafeMath` restores this intuition by reverting the transaction when an
                     * operation overflows.
                     *
                     * Using this library instead of the unchecked operations eliminates an entire
                     * class of bugs, so it's recommended to use it always.
                     */
                    library SafeMath {
                        /**
                         * @dev Returns the addition of two unsigned integers, with an overflow flag.
                         *
                         * _Available since v3.4._
                         */
                        function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                            uint256 c = a + b;
                            if (c < a) return (false, 0);
                            return (true, c);
                        }
                        /**
                         * @dev Returns the substraction of two unsigned integers, with an overflow flag.
                         *
                         * _Available since v3.4._
                         */
                        function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                            if (b > a) return (false, 0);
                            return (true, a - b);
                        }
                        /**
                         * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
                         *
                         * _Available since v3.4._
                         */
                        function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
                            // benefit is lost if 'b' is also tested.
                            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
                            if (a == 0) return (true, 0);
                            uint256 c = a * b;
                            if (c / a != b) return (false, 0);
                            return (true, c);
                        }
                        /**
                         * @dev Returns the division of two unsigned integers, with a division by zero flag.
                         *
                         * _Available since v3.4._
                         */
                        function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                            if (b == 0) return (false, 0);
                            return (true, a / b);
                        }
                        /**
                         * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
                         *
                         * _Available since v3.4._
                         */
                        function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                            if (b == 0) return (false, 0);
                            return (true, a % b);
                        }
                        /**
                         * @dev Returns the addition of two unsigned integers, reverting on
                         * overflow.
                         *
                         * Counterpart to Solidity's `+` operator.
                         *
                         * Requirements:
                         *
                         * - Addition cannot overflow.
                         */
                        function add(uint256 a, uint256 b) internal pure returns (uint256) {
                            uint256 c = a + b;
                            require(c >= a, "SafeMath: addition overflow");
                            return c;
                        }
                        /**
                         * @dev Returns the subtraction of two unsigned integers, reverting on
                         * overflow (when the result is negative).
                         *
                         * Counterpart to Solidity's `-` operator.
                         *
                         * Requirements:
                         *
                         * - Subtraction cannot overflow.
                         */
                        function sub(uint256 a, uint256 b) internal pure returns (uint256) {
                            require(b <= a, "SafeMath: subtraction overflow");
                            return a - b;
                        }
                        /**
                         * @dev Returns the multiplication of two unsigned integers, reverting on
                         * overflow.
                         *
                         * Counterpart to Solidity's `*` operator.
                         *
                         * Requirements:
                         *
                         * - Multiplication cannot overflow.
                         */
                        function mul(uint256 a, uint256 b) internal pure returns (uint256) {
                            if (a == 0) return 0;
                            uint256 c = a * b;
                            require(c / a == b, "SafeMath: multiplication overflow");
                            return c;
                        }
                        /**
                         * @dev Returns the integer division of two unsigned integers, reverting on
                         * division by zero. The result is rounded towards zero.
                         *
                         * Counterpart to Solidity's `/` operator. Note: this function uses a
                         * `revert` opcode (which leaves remaining gas untouched) while Solidity
                         * uses an invalid opcode to revert (consuming all remaining gas).
                         *
                         * Requirements:
                         *
                         * - The divisor cannot be zero.
                         */
                        function div(uint256 a, uint256 b) internal pure returns (uint256) {
                            require(b > 0, "SafeMath: division by zero");
                            return a / b;
                        }
                        /**
                         * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                         * reverting when dividing by zero.
                         *
                         * Counterpart to Solidity's `%` operator. This function uses a `revert`
                         * opcode (which leaves remaining gas untouched) while Solidity uses an
                         * invalid opcode to revert (consuming all remaining gas).
                         *
                         * Requirements:
                         *
                         * - The divisor cannot be zero.
                         */
                        function mod(uint256 a, uint256 b) internal pure returns (uint256) {
                            require(b > 0, "SafeMath: modulo by zero");
                            return a % b;
                        }
                        /**
                         * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
                         * overflow (when the result is negative).
                         *
                         * CAUTION: This function is deprecated because it requires allocating memory for the error
                         * message unnecessarily. For custom revert reasons use {trySub}.
                         *
                         * Counterpart to Solidity's `-` operator.
                         *
                         * Requirements:
                         *
                         * - Subtraction cannot overflow.
                         */
                        function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                            require(b <= a, errorMessage);
                            return a - b;
                        }
                        /**
                         * @dev Returns the integer division of two unsigned integers, reverting with custom message on
                         * division by zero. The result is rounded towards zero.
                         *
                         * CAUTION: This function is deprecated because it requires allocating memory for the error
                         * message unnecessarily. For custom revert reasons use {tryDiv}.
                         *
                         * Counterpart to Solidity's `/` operator. Note: this function uses a
                         * `revert` opcode (which leaves remaining gas untouched) while Solidity
                         * uses an invalid opcode to revert (consuming all remaining gas).
                         *
                         * Requirements:
                         *
                         * - The divisor cannot be zero.
                         */
                        function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                            require(b > 0, errorMessage);
                            return a / b;
                        }
                        /**
                         * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                         * reverting with custom message when dividing by zero.
                         *
                         * CAUTION: This function is deprecated because it requires allocating memory for the error
                         * message unnecessarily. For custom revert reasons use {tryMod}.
                         *
                         * Counterpart to Solidity's `%` operator. This function uses a `revert`
                         * opcode (which leaves remaining gas untouched) while Solidity uses an
                         * invalid opcode to revert (consuming all remaining gas).
                         *
                         * Requirements:
                         *
                         * - The divisor cannot be zero.
                         */
                        function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                            require(b > 0, errorMessage);
                            return a % b;
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2019-2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "../libraries/MerkleLib.sol";
                    import "@openzeppelin/contracts/math/SafeMath.sol";
                    library ChallengeLib {
                        using SafeMath for uint256;
                        function firstSegmentSize(uint256 totalCount, uint256 bisectionCount)
                            internal
                            pure
                            returns (uint256)
                        {
                            return totalCount / bisectionCount + (totalCount % bisectionCount);
                        }
                        function otherSegmentSize(uint256 totalCount, uint256 bisectionCount)
                            internal
                            pure
                            returns (uint256)
                        {
                            return totalCount / bisectionCount;
                        }
                        function bisectionChunkHash(
                            uint256 _segmentStart,
                            uint256 _segmentLength,
                            bytes32 _startHash,
                            bytes32 _endHash
                        ) internal pure returns (bytes32) {
                            return keccak256(abi.encodePacked(_segmentStart, _segmentLength, _startHash, _endHash));
                        }
                        function assertionHash(uint256 _avmGasUsed, bytes32 _restHash) internal pure returns (bytes32) {
                            // Note: make sure this doesn't return Challenge.UNREACHABLE_ASSERTION (currently 0)
                            return keccak256(abi.encodePacked(_avmGasUsed, _restHash));
                        }
                        function assertionRestHash(
                            uint256 _totalMessagesRead,
                            bytes32 _machineState,
                            bytes32 _sendAcc,
                            uint256 _sendCount,
                            bytes32 _logAcc,
                            uint256 _logCount
                        ) internal pure returns (bytes32) {
                            return
                                keccak256(
                                    abi.encodePacked(
                                        _totalMessagesRead,
                                        _machineState,
                                        _sendAcc,
                                        _sendCount,
                                        _logAcc,
                                        _logCount
                                    )
                                );
                        }
                        function updatedBisectionRoot(
                            bytes32[] memory _chainHashes,
                            uint256 _challengedSegmentStart,
                            uint256 _challengedSegmentLength
                        ) internal pure returns (bytes32) {
                            uint256 bisectionCount = _chainHashes.length - 1;
                            bytes32[] memory hashes = new bytes32[](bisectionCount);
                            uint256 chunkSize = ChallengeLib.firstSegmentSize(_challengedSegmentLength, bisectionCount);
                            uint256 segmentStart = _challengedSegmentStart;
                            hashes[0] = ChallengeLib.bisectionChunkHash(
                                segmentStart,
                                chunkSize,
                                _chainHashes[0],
                                _chainHashes[1]
                            );
                            segmentStart = segmentStart.add(chunkSize);
                            chunkSize = ChallengeLib.otherSegmentSize(_challengedSegmentLength, bisectionCount);
                            for (uint256 i = 1; i < bisectionCount; i++) {
                                hashes[i] = ChallengeLib.bisectionChunkHash(
                                    segmentStart,
                                    chunkSize,
                                    _chainHashes[i],
                                    _chainHashes[i + 1]
                                );
                                segmentStart = segmentStart.add(chunkSize);
                            }
                            return MerkleLib.generateRoot(hashes);
                        }
                        function verifySegmentProof(
                            bytes32 challengeState,
                            bytes32 item,
                            bytes32[] calldata _merkleNodes,
                            uint256 _merkleRoute
                        ) internal pure returns (bool) {
                            return challengeState == MerkleLib.calculateRoot(_merkleNodes, _merkleRoute, item);
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2019-2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    library MerkleLib {
                        function generateRoot(bytes32[] memory _hashes) internal pure returns (bytes32) {
                            bytes32[] memory prevLayer = _hashes;
                            while (prevLayer.length > 1) {
                                bytes32[] memory nextLayer = new bytes32[]((prevLayer.length + 1) / 2);
                                for (uint256 i = 0; i < nextLayer.length; i++) {
                                    if (2 * i + 1 < prevLayer.length) {
                                        nextLayer[i] = keccak256(
                                            abi.encodePacked(prevLayer[2 * i], prevLayer[2 * i + 1])
                                        );
                                    } else {
                                        nextLayer[i] = prevLayer[2 * i];
                                    }
                                }
                                prevLayer = nextLayer;
                            }
                            return prevLayer[0];
                        }
                        function calculateRoot(
                            bytes32[] memory nodes,
                            uint256 route,
                            bytes32 item
                        ) internal pure returns (bytes32) {
                            uint256 proofItems = nodes.length;
                            require(proofItems <= 256);
                            bytes32 h = item;
                            for (uint256 i = 0; i < proofItems; i++) {
                                if (route % 2 == 0) {
                                    h = keccak256(abi.encodePacked(nodes[i], h));
                                } else {
                                    h = keccak256(abi.encodePacked(h, nodes[i]));
                                }
                                route /= 2;
                            }
                            return h;
                        }
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2019, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    interface ICloneable {
                        function isMaster() external view returns (bool);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2020, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "../bridge/interfaces/IBridge.sol";
                    import "../bridge/interfaces/ISequencerInbox.sol";
                    interface IOneStepProof {
                        // Bridges is sequencer bridge then delayed bridge
                        function executeStep(
                            address[2] calldata bridges,
                            uint256 initialMessagesRead,
                            bytes32[2] calldata accs,
                            bytes calldata proof,
                            bytes calldata bproof
                        )
                            external
                            view
                            returns (
                                uint64 gas,
                                uint256 afterMessagesRead,
                                bytes32[4] memory fields
                            );
                        function executeStepDebug(
                            address[2] calldata bridges,
                            uint256 initialMessagesRead,
                            bytes32[2] calldata accs,
                            bytes calldata proof,
                            bytes calldata bproof
                        ) external view returns (string memory startMachine, string memory afterMachine);
                    }
                    // SPDX-License-Identifier: Apache-2.0
                    /*
                     * Copyright 2019-2021, Offchain Labs, Inc.
                     *
                     * Licensed under the Apache License, Version 2.0 (the "License");
                     * you may not use this file except in compliance with the License.
                     * You may obtain a copy of the License at
                     *
                     *    http://www.apache.org/licenses/LICENSE-2.0
                     *
                     * Unless required by applicable law or agreed to in writing, software
                     * distributed under the License is distributed on an "AS IS" BASIS,
                     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                     * See the License for the specific language governing permissions and
                     * limitations under the License.
                     */
                    pragma solidity ^0.6.11;
                    import "./interfaces/IOutbox.sol";
                    import "./interfaces/IBridge.sol";
                    import "./Messages.sol";
                    import "../libraries/MerkleLib.sol";
                    import "../libraries/BytesLib.sol";
                    import "../libraries/Cloneable.sol";
                    import "@openzeppelin/contracts/proxy/BeaconProxy.sol";
                    import "@openzeppelin/contracts/proxy/UpgradeableBeacon.sol";
                    contract Outbox is IOutbox, Cloneable {
                        using BytesLib for bytes;
                        struct OutboxEntry {
                            // merkle root of outputs
                            bytes32 root;
                            // mapping from output id => is spent
                            mapping(bytes32 => bool) spentOutput;
                        }
                        bytes1 internal constant MSG_ROOT = 0;
                        uint8 internal constant SendType_sendTxToL1 = 3;
                        address public rollup;
                        IBridge public bridge;
                        mapping(uint256 => OutboxEntry) public outboxEntries;
                        struct L2ToL1Context {
                            uint128 l2Block;
                            uint128 l1Block;
                            uint128 timestamp;
                            uint128 batchNum;
                            bytes32 outputId;
                            address sender;
                        }
                        // Note, these variables are set and then wiped during a single transaction.
                        // Therefore their values don't need to be maintained, and their slots will
                        // be empty outside of transactions
                        L2ToL1Context internal context;
                        uint128 public constant OUTBOX_VERSION = 1;
                        function initialize(address _rollup, IBridge _bridge) external {
                            require(rollup == address(0), "ALREADY_INIT");
                            rollup = _rollup;
                            bridge = _bridge;
                        }
                        /// @notice When l2ToL1Sender returns a nonzero address, the message was originated by an L2 account
                        /// When the return value is zero, that means this is a system message
                        /// @dev the l2ToL1Sender behaves as the tx.origin, the msg.sender should be validated to protect against reentrancies
                        function l2ToL1Sender() external view override returns (address) {
                            return context.sender;
                        }
                        function l2ToL1Block() external view override returns (uint256) {
                            return uint256(context.l2Block);
                        }
                        function l2ToL1EthBlock() external view override returns (uint256) {
                            return uint256(context.l1Block);
                        }
                        function l2ToL1Timestamp() external view override returns (uint256) {
                            return uint256(context.timestamp);
                        }
                        function l2ToL1BatchNum() external view override returns (uint256) {
                            return uint256(context.batchNum);
                        }
                        function l2ToL1OutputId() external view override returns (bytes32) {
                            return context.outputId;
                        }
                        function processOutgoingMessages(bytes calldata sendsData, uint256[] calldata sendLengths)
                            external
                            override
                        {
                            require(msg.sender == rollup, "ONLY_ROLLUP");
                            // If we've reached here, we've already confirmed that sum(sendLengths) == sendsData.length
                            uint256 messageCount = sendLengths.length;
                            uint256 offset = 0;
                            for (uint256 i = 0; i < messageCount; i++) {
                                handleOutgoingMessage(bytes(sendsData[offset:offset + sendLengths[i]]));
                                offset += sendLengths[i];
                            }
                        }
                        function handleOutgoingMessage(bytes memory data) private {
                            // Otherwise we have an unsupported message type and we skip the message
                            if (data[0] == MSG_ROOT) {
                                require(data.length == 97, "BAD_LENGTH");
                                uint256 batchNum = data.toUint(1);
                                // Ensure no outbox entry already exists w/ batch number
                                require(!outboxEntryExists(batchNum), "ENTRY_ALREADY_EXISTS");
                                // This is the total number of msgs included in the root, it can be used to
                                // detect when all msgs were executed against a root.
                                // It currently isn't stored, but instead emitted in an event for utility
                                uint256 numInBatch = data.toUint(33);
                                bytes32 outputRoot = data.toBytes32(65);
                                OutboxEntry memory newOutboxEntry = OutboxEntry(outputRoot);
                                outboxEntries[batchNum] = newOutboxEntry;
                                // keeping redundant batchnum in event (batchnum and old outboxindex field) for outbox version interface compatibility
                                emit OutboxEntryCreated(batchNum, batchNum, outputRoot, numInBatch);
                            }
                        }
                        /**
                         * @notice Executes a messages in an Outbox entry.
                         * @dev Reverts if dispute period hasn't expired, since the outbox entry
                         * is only created once the rollup confirms the respective assertion.
                         * @param batchNum Index of OutboxEntry in outboxEntries array
                         * @param proof Merkle proof of message inclusion in outbox entry
                         * @param index Merkle path to message
                         * @param l2Sender sender if original message (i.e., caller of ArbSys.sendTxToL1)
                         * @param destAddr destination address for L1 contract call
                         * @param l2Block l2 block number at which sendTxToL1 call was made
                         * @param l1Block l1 block number at which sendTxToL1 call was made
                         * @param l2Timestamp l2 Timestamp at which sendTxToL1 call was made
                         * @param amount value in L1 message in wei
                         * @param calldataForL1 abi-encoded L1 message data
                         */
                        function executeTransaction(
                            uint256 batchNum,
                            bytes32[] calldata proof,
                            uint256 index,
                            address l2Sender,
                            address destAddr,
                            uint256 l2Block,
                            uint256 l1Block,
                            uint256 l2Timestamp,
                            uint256 amount,
                            bytes calldata calldataForL1
                        ) external virtual {
                            bytes32 outputId;
                            {
                                bytes32 userTx =
                                    calculateItemHash(
                                        l2Sender,
                                        destAddr,
                                        l2Block,
                                        l1Block,
                                        l2Timestamp,
                                        amount,
                                        calldataForL1
                                    );
                                outputId = recordOutputAsSpent(batchNum, proof, index, userTx);
                                emit OutBoxTransactionExecuted(destAddr, l2Sender, batchNum, index);
                            }
                            // we temporarily store the previous values so the outbox can naturally
                            // unwind itself when there are nested calls to `executeTransaction`
                            L2ToL1Context memory prevContext = context;
                            context = L2ToL1Context({
                                sender: l2Sender,
                                l2Block: uint128(l2Block),
                                l1Block: uint128(l1Block),
                                timestamp: uint128(l2Timestamp),
                                batchNum: uint128(batchNum),
                                outputId: outputId
                            });
                            // set and reset vars around execution so they remain valid during call
                            executeBridgeCall(destAddr, amount, calldataForL1);
                            context = prevContext;
                        }
                        function recordOutputAsSpent(
                            uint256 batchNum,
                            bytes32[] memory proof,
                            uint256 path,
                            bytes32 item
                        ) internal returns (bytes32) {
                            require(proof.length < 256, "PROOF_TOO_LONG");
                            require(path < 2**proof.length, "PATH_NOT_MINIMAL");
                            // Hash the leaf an extra time to prove it's a leaf
                            bytes32 calcRoot = calculateMerkleRoot(proof, path, item);
                            OutboxEntry storage outboxEntry = outboxEntries[batchNum];
                            require(outboxEntry.root != bytes32(0), "NO_OUTBOX_ENTRY");
                            // With a minimal path, the pair of path and proof length should always identify
                            // a unique leaf. The path itself is not enough since the path length to different
                            // leaves could potentially be different
                            bytes32 uniqueKey = keccak256(abi.encodePacked(path, proof.length));
                            require(!outboxEntry.spentOutput[uniqueKey], "ALREADY_SPENT");
                            require(calcRoot == outboxEntry.root, "BAD_ROOT");
                            outboxEntry.spentOutput[uniqueKey] = true;
                            return uniqueKey;
                        }
                        function executeBridgeCall(
                            address destAddr,
                            uint256 amount,
                            bytes memory data
                        ) internal {
                            (bool success, bytes memory returndata) = bridge.executeCall(destAddr, amount, data);
                            if (!success) {
                                if (returndata.length > 0) {
                                    // solhint-disable-next-line no-inline-assembly
                                    assembly {
                                        let returndata_size := mload(returndata)
                                        revert(add(32, returndata), returndata_size)
                                    }
                                } else {
                                    revert("BRIDGE_CALL_FAILED");
                                }
                            }
                        }
                        function calculateItemHash(
                            address l2Sender,
                            address destAddr,
                            uint256 l2Block,
                            uint256 l1Block,
                            uint256 l2Timestamp,
                            uint256 amount,
                            bytes calldata calldataForL1
                        ) public pure returns (bytes32) {
                            return
                                keccak256(
                                    abi.encodePacked(
                                        SendType_sendTxToL1,
                                        uint256(uint160(bytes20(l2Sender))),
                                        uint256(uint160(bytes20(destAddr))),
                                        l2Block,
                                        l1Block,
                                        l2Timestamp,
                                        amount,
                                        calldataForL1
                                    )
                                );
                        }
                        function calculateMerkleRoot(
                            bytes32[] memory proof,
                            uint256 path,
                            bytes32 item
                        ) public pure returns (bytes32) {
                            return MerkleLib.calculateRoot(proof, path, keccak256(abi.encodePacked(item)));
                        }
                        function outboxEntryExists(uint256 batchNum) public view override returns (bool) {
                            return outboxEntries[batchNum].root != bytes32(0);
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "../utils/ContextUpgradeable.sol";
                    import "../proxy/Initializable.sol";
                    /**
                     * @dev Contract module which provides a basic access control mechanism, where
                     * there is an account (an owner) that can be granted exclusive access to
                     * specific functions.
                     *
                     * By default, the owner account will be the one that deploys the contract. This
                     * can later be changed with {transferOwnership}.
                     *
                     * This module is used through inheritance. It will make available the modifier
                     * `onlyOwner`, which can be applied to your functions to restrict their use to
                     * the owner.
                     */
                    abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable {
                        address private _owner;
                        event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
                        /**
                         * @dev Initializes the contract setting the deployer as the initial owner.
                         */
                        function __Ownable_init() internal initializer {
                            __Context_init_unchained();
                            __Ownable_init_unchained();
                        }
                        function __Ownable_init_unchained() internal initializer {
                            address msgSender = _msgSender();
                            _owner = msgSender;
                            emit OwnershipTransferred(address(0), msgSender);
                        }
                        /**
                         * @dev Returns the address of the current owner.
                         */
                        function owner() public view virtual returns (address) {
                            return _owner;
                        }
                        /**
                         * @dev Throws if called by any account other than the owner.
                         */
                        modifier onlyOwner() {
                            require(owner() == _msgSender(), "Ownable: caller is not the owner");
                            _;
                        }
                        /**
                         * @dev Leaves the contract without owner. It will not be possible to call
                         * `onlyOwner` functions anymore. Can only be called by the current owner.
                         *
                         * NOTE: Renouncing ownership will leave the contract without an owner,
                         * thereby removing any functionality that is only available to the owner.
                         */
                        function renounceOwnership() public virtual onlyOwner {
                            emit OwnershipTransferred(_owner, address(0));
                            _owner = address(0);
                        }
                        /**
                         * @dev Transfers ownership of the contract to a new account (`newOwner`).
                         * Can only be called by the current owner.
                         */
                        function transferOwnership(address newOwner) public virtual onlyOwner {
                            require(newOwner != address(0), "Ownable: new owner is the zero address");
                            emit OwnershipTransferred(_owner, newOwner);
                            _owner = newOwner;
                        }
                        uint256[49] private __gap;
                    }
                    // SPDX-License-Identifier: MIT
                    /*
                     * @title Solidity Bytes Arrays Utils
                     * @author Gonçalo Sá <goncalo.sa@consensys.net>
                     *
                     * @dev Bytes tightly packed arrays utility library for ethereum contracts written in Solidity.
                     *      The library lets you concatenate, slice and type cast bytes arrays both in memory and storage.
                     */
                    pragma solidity ^0.6.11;
                    /* solhint-disable no-inline-assembly */
                    library BytesLib {
                        function toAddress(bytes memory _bytes, uint256 _start) internal pure returns (address) {
                            require(_bytes.length >= (_start + 20), "Read out of bounds");
                            address tempAddress;
                            assembly {
                                tempAddress := div(mload(add(add(_bytes, 0x20), _start)), 0x1000000000000000000000000)
                            }
                            return tempAddress;
                        }
                        function toUint8(bytes memory _bytes, uint256 _start) internal pure returns (uint8) {
                            require(_bytes.length >= (_start + 1), "Read out of bounds");
                            uint8 tempUint;
                            assembly {
                                tempUint := mload(add(add(_bytes, 0x1), _start))
                            }
                            return tempUint;
                        }
                        function toUint(bytes memory _bytes, uint256 _start) internal pure returns (uint256) {
                            require(_bytes.length >= (_start + 32), "Read out of bounds");
                            uint256 tempUint;
                            assembly {
                                tempUint := mload(add(add(_bytes, 0x20), _start))
                            }
                            return tempUint;
                        }
                        function toBytes32(bytes memory _bytes, uint256 _start) internal pure returns (bytes32) {
                            require(_bytes.length >= (_start + 32), "Read out of bounds");
                            bytes32 tempBytes32;
                            assembly {
                                tempBytes32 := mload(add(add(_bytes, 0x20), _start))
                            }
                            return tempBytes32;
                        }
                    }
                    /* solhint-enable no-inline-assembly */
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "./Proxy.sol";
                    import "../utils/Address.sol";
                    import "./IBeacon.sol";
                    /**
                     * @dev This contract implements a proxy that gets the implementation address for each call from a {UpgradeableBeacon}.
                     *
                     * The beacon address is stored in storage slot `uint256(keccak256('eip1967.proxy.beacon')) - 1`, so that it doesn't
                     * conflict with the storage layout of the implementation behind the proxy.
                     *
                     * _Available since v3.4._
                     */
                    contract BeaconProxy is Proxy {
                        /**
                         * @dev The storage slot of the UpgradeableBeacon contract which defines the implementation for this proxy.
                         * This is bytes32(uint256(keccak256('eip1967.proxy.beacon')) - 1)) and is validated in the constructor.
                         */
                        bytes32 private constant _BEACON_SLOT = 0xa3f0ad74e5423aebfd80d3ef4346578335a9a72aeaee59ff6cb3582b35133d50;
                        /**
                         * @dev Initializes the proxy with `beacon`.
                         *
                         * If `data` is nonempty, it's used as data in a delegate call to the implementation returned by the beacon. This
                         * will typically be an encoded function call, and allows initializating the storage of the proxy like a Solidity
                         * constructor.
                         *
                         * Requirements:
                         *
                         * - `beacon` must be a contract with the interface {IBeacon}.
                         */
                        constructor(address beacon, bytes memory data) public payable {
                            assert(_BEACON_SLOT == bytes32(uint256(keccak256("eip1967.proxy.beacon")) - 1));
                            _setBeacon(beacon, data);
                        }
                        /**
                         * @dev Returns the current beacon address.
                         */
                        function _beacon() internal view virtual returns (address beacon) {
                            bytes32 slot = _BEACON_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                beacon := sload(slot)
                            }
                        }
                        /**
                         * @dev Returns the current implementation address of the associated beacon.
                         */
                        function _implementation() internal view virtual override returns (address) {
                            return IBeacon(_beacon()).implementation();
                        }
                        /**
                         * @dev Changes the proxy to use a new beacon.
                         *
                         * If `data` is nonempty, it's used as data in a delegate call to the implementation returned by the beacon.
                         *
                         * Requirements:
                         *
                         * - `beacon` must be a contract.
                         * - The implementation returned by `beacon` must be a contract.
                         */
                        function _setBeacon(address beacon, bytes memory data) internal virtual {
                            require(
                                Address.isContract(beacon),
                                "BeaconProxy: beacon is not a contract"
                            );
                            require(
                                Address.isContract(IBeacon(beacon).implementation()),
                                "BeaconProxy: beacon implementation is not a contract"
                            );
                            bytes32 slot = _BEACON_SLOT;
                            // solhint-disable-next-line no-inline-assembly
                            assembly {
                                sstore(slot, beacon)
                            }
                            if (data.length > 0) {
                                Address.functionDelegateCall(_implementation(), data, "BeaconProxy: function call failed");
                            }
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "./IBeacon.sol";
                    import "../access/Ownable.sol";
                    import "../utils/Address.sol";
                    /**
                     * @dev This contract is used in conjunction with one or more instances of {BeaconProxy} to determine their
                     * implementation contract, which is where they will delegate all function calls.
                     *
                     * An owner is able to change the implementation the beacon points to, thus upgrading the proxies that use this beacon.
                     */
                    contract UpgradeableBeacon is IBeacon, Ownable {
                        address private _implementation;
                        /**
                         * @dev Emitted when the implementation returned by the beacon is changed.
                         */
                        event Upgraded(address indexed implementation);
                        /**
                         * @dev Sets the address of the initial implementation, and the deployer account as the owner who can upgrade the
                         * beacon.
                         */
                        constructor(address implementation_) public {
                            _setImplementation(implementation_);
                        }
                        /**
                         * @dev Returns the current implementation address.
                         */
                        function implementation() public view virtual override returns (address) {
                            return _implementation;
                        }
                        /**
                         * @dev Upgrades the beacon to a new implementation.
                         *
                         * Emits an {Upgraded} event.
                         *
                         * Requirements:
                         *
                         * - msg.sender must be the owner of the contract.
                         * - `newImplementation` must be a contract.
                         */
                        function upgradeTo(address newImplementation) public virtual onlyOwner {
                            _setImplementation(newImplementation);
                            emit Upgraded(newImplementation);
                        }
                        /**
                         * @dev Sets the implementation contract address for this beacon
                         *
                         * Requirements:
                         *
                         * - `newImplementation` must be a contract.
                         */
                        function _setImplementation(address newImplementation) private {
                            require(Address.isContract(newImplementation), "UpgradeableBeacon: implementation is not a contract");
                            _implementation = newImplementation;
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    /**
                     * @dev This is the interface that {BeaconProxy} expects of its beacon.
                     */
                    interface IBeacon {
                        /**
                         * @dev Must return an address that can be used as a delegate call target.
                         *
                         * {BeaconProxy} will check that this address is a contract.
                         */
                        function implementation() external view returns (address);
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "../utils/Context.sol";
                    /**
                     * @dev Contract module which provides a basic access control mechanism, where
                     * there is an account (an owner) that can be granted exclusive access to
                     * specific functions.
                     *
                     * By default, the owner account will be the one that deploys the contract. This
                     * can later be changed with {transferOwnership}.
                     *
                     * This module is used through inheritance. It will make available the modifier
                     * `onlyOwner`, which can be applied to your functions to restrict their use to
                     * the owner.
                     */
                    abstract contract Ownable is Context {
                        address private _owner;
                        event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
                        /**
                         * @dev Initializes the contract setting the deployer as the initial owner.
                         */
                        constructor () internal {
                            address msgSender = _msgSender();
                            _owner = msgSender;
                            emit OwnershipTransferred(address(0), msgSender);
                        }
                        /**
                         * @dev Returns the address of the current owner.
                         */
                        function owner() public view virtual returns (address) {
                            return _owner;
                        }
                        /**
                         * @dev Throws if called by any account other than the owner.
                         */
                        modifier onlyOwner() {
                            require(owner() == _msgSender(), "Ownable: caller is not the owner");
                            _;
                        }
                        /**
                         * @dev Leaves the contract without owner. It will not be possible to call
                         * `onlyOwner` functions anymore. Can only be called by the current owner.
                         *
                         * NOTE: Renouncing ownership will leave the contract without an owner,
                         * thereby removing any functionality that is only available to the owner.
                         */
                        function renounceOwnership() public virtual onlyOwner {
                            emit OwnershipTransferred(_owner, address(0));
                            _owner = address(0);
                        }
                        /**
                         * @dev Transfers ownership of the contract to a new account (`newOwner`).
                         * Can only be called by the current owner.
                         */
                        function transferOwnership(address newOwner) public virtual onlyOwner {
                            require(newOwner != address(0), "Ownable: new owner is the zero address");
                            emit OwnershipTransferred(_owner, newOwner);
                            _owner = newOwner;
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.0 <0.8.0;
                    import "../proxy/Initializable.sol";
                    /*
                     * @dev Provides information about the current execution context, including the
                     * sender of the transaction and its data. While these are generally available
                     * via msg.sender and msg.data, they should not be accessed in such a direct
                     * manner, since when dealing with GSN meta-transactions the account sending and
                     * paying for execution may not be the actual sender (as far as an application
                     * is concerned).
                     *
                     * This contract is only required for intermediate, library-like contracts.
                     */
                    abstract contract ContextUpgradeable is Initializable {
                        function __Context_init() internal initializer {
                            __Context_init_unchained();
                        }
                        function __Context_init_unchained() internal initializer {
                        }
                        function _msgSender() internal view virtual returns (address payable) {
                            return msg.sender;
                        }
                        function _msgData() internal view virtual returns (bytes memory) {
                            this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
                            return msg.data;
                        }
                        uint256[50] private __gap;
                    }
                    // SPDX-License-Identifier: MIT
                    // solhint-disable-next-line compiler-version
                    pragma solidity >=0.4.24 <0.8.0;
                    import "../utils/AddressUpgradeable.sol";
                    /**
                     * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
                     * behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
                     * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
                     * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
                     *
                     * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
                     * possible by providing the encoded function call as the `_data` argument to {UpgradeableProxy-constructor}.
                     *
                     * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
                     * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
                     */
                    abstract contract Initializable {
                        /**
                         * @dev Indicates that the contract has been initialized.
                         */
                        bool private _initialized;
                        /**
                         * @dev Indicates that the contract is in the process of being initialized.
                         */
                        bool private _initializing;
                        /**
                         * @dev Modifier to protect an initializer function from being invoked twice.
                         */
                        modifier initializer() {
                            require(_initializing || _isConstructor() || !_initialized, "Initializable: contract is already initialized");
                            bool isTopLevelCall = !_initializing;
                            if (isTopLevelCall) {
                                _initializing = true;
                                _initialized = true;
                            }
                            _;
                            if (isTopLevelCall) {
                                _initializing = false;
                            }
                        }
                        /// @dev Returns true if and only if the function is running in the constructor
                        function _isConstructor() private view returns (bool) {
                            return !AddressUpgradeable.isContract(address(this));
                        }
                    }
                    // SPDX-License-Identifier: MIT
                    pragma solidity >=0.6.2 <0.8.0;
                    /**
                     * @dev Collection of functions related to the address type
                     */
                    library AddressUpgradeable {
                        /**
                         * @dev Returns true if `account` is a contract.
                         *
                         * [IMPORTANT]
                         * ====
                         * It is unsafe to assume that an address for which this function returns
                         * false is an externally-owned account (EOA) and not a contract.
                         *
                         * Among others, `isContract` will return false for the following
                         * types of addresses:
                         *
                         *  - an externally-owned account
                         *  - a contract in construction
                         *  - an address where a contract will be created
                         *  - an address where a contract lived, but was destroyed
                         * ====
                         */
                        function isContract(address account) internal view returns (bool) {
                            // This method relies on extcodesize, which returns 0 for contracts in
                            // construction, since the code is only stored at the end of the
                            // constructor execution.
                            uint256 size;
                            // solhint-disable-next-line no-inline-assembly
                            assembly { size := extcodesize(account) }
                            return size > 0;
                        }
                        /**
                         * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
                         * `recipient`, forwarding all available gas and reverting on errors.
                         *
                         * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
                         * of certain opcodes, possibly making contracts go over the 2300 gas limit
                         * imposed by `transfer`, making them unable to receive funds via
                         * `transfer`. {sendValue} removes this limitation.
                         *
                         * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
                         *
                         * IMPORTANT: because control is transferred to `recipient`, care must be
                         * taken to not create reentrancy vulnerabilities. Consider using
                         * {ReentrancyGuard} or the
                         * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
                         */
                        function sendValue(address payable recipient, uint256 amount) internal {
                            require(address(this).balance >= amount, "Address: insufficient balance");
                            // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
                            (bool success, ) = recipient.call{ value: amount }("");
                            require(success, "Address: unable to send value, recipient may have reverted");
                        }
                        /**
                         * @dev Performs a Solidity function call using a low level `call`. A
                         * plain`call` is an unsafe replacement for a function call: use this
                         * function instead.
                         *
                         * If `target` reverts with a revert reason, it is bubbled up by this
                         * function (like regular Solidity function calls).
                         *
                         * Returns the raw returned data. To convert to the expected return value,
                         * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
                         *
                         * Requirements:
                         *
                         * - `target` must be a contract.
                         * - calling `target` with `data` must not revert.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                          return functionCall(target, data, "Address: low-level call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
                         * `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, 0, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but also transferring `value` wei to `target`.
                         *
                         * Requirements:
                         *
                         * - the calling contract must have an ETH balance of at least `value`.
                         * - the called Solidity function must be `payable`.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                            return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
                         * with `errorMessage` as a fallback revert reason when `target` reverts.
                         *
                         * _Available since v3.1._
                         */
                        function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
                            require(address(this).balance >= value, "Address: insufficient balance for call");
                            require(isContract(target), "Address: call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.call{ value: value }(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                            return functionStaticCall(target, data, "Address: low-level static call failed");
                        }
                        /**
                         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                         * but performing a static call.
                         *
                         * _Available since v3.3._
                         */
                        function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
                            require(isContract(target), "Address: static call to non-contract");
                            // solhint-disable-next-line avoid-low-level-calls
                            (bool success, bytes memory returndata) = target.staticcall(data);
                            return _verifyCallResult(success, returndata, errorMessage);
                        }
                        function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
                            if (success) {
                                return returndata;
                            } else {
                                // Look for revert reason and bubble it up if present
                                if (returndata.length > 0) {
                                    // The easiest way to bubble the revert reason is using memory via assembly
                                    // solhint-disable-next-line no-inline-assembly
                                    assembly {
                                        let returndata_size := mload(returndata)
                                        revert(add(32, returndata), returndata_size)
                                    }
                                } else {
                                    revert(errorMessage);
                                }
                            }
                        }
                    }