// File: contracts/ERC20Interface.sol

pragma solidity 0.4.18;


// https://github.com/ethereum/EIPs/issues/20
interface ERC20 {
    function totalSupply() public view returns (uint supply);
    function balanceOf(address _owner) public view returns (uint balance);
    function transfer(address _to, uint _value) public returns (bool success);
    function transferFrom(address _from, address _to, uint _value) public returns (bool success);
    function approve(address _spender, uint _value) public returns (bool success);
    function allowance(address _owner, address _spender) public view returns (uint remaining);
    function decimals() public view returns(uint digits);
    event Approval(address indexed _owner, address indexed _spender, uint _value);
}

// File: contracts/Utils.sol

pragma solidity 0.4.18;



/// @title Kyber constants contract
contract Utils {

    ERC20 constant internal ETH_TOKEN_ADDRESS = ERC20(0x00eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee);
    uint  constant internal PRECISION = (10**18);
    uint  constant internal MAX_QTY   = (10**28); // 10B tokens
    uint  constant internal MAX_RATE  = (PRECISION * 10**6); // up to 1M tokens per ETH
    uint  constant internal MAX_DECIMALS = 18;
    uint  constant internal ETH_DECIMALS = 18;
    mapping(address=>uint) internal decimals;

    function setDecimals(ERC20 token) internal {
        if (token == ETH_TOKEN_ADDRESS) decimals[token] = ETH_DECIMALS;
        else decimals[token] = token.decimals();
    }

    function getDecimals(ERC20 token) internal view returns(uint) {
        if (token == ETH_TOKEN_ADDRESS) return ETH_DECIMALS; // save storage access
        uint tokenDecimals = decimals[token];
        // technically, there might be token with decimals 0
        // moreover, very possible that old tokens have decimals 0
        // these tokens will just have higher gas fees.
        if(tokenDecimals == 0) return token.decimals();

        return tokenDecimals;
    }

    function calcDstQty(uint srcQty, uint srcDecimals, uint dstDecimals, uint rate) internal pure returns(uint) {
        require(srcQty <= MAX_QTY);
        require(rate <= MAX_RATE);

        if (dstDecimals >= srcDecimals) {
            require((dstDecimals - srcDecimals) <= MAX_DECIMALS);
            return (srcQty * rate * (10**(dstDecimals - srcDecimals))) / PRECISION;
        } else {
            require((srcDecimals - dstDecimals) <= MAX_DECIMALS);
            return (srcQty * rate) / (PRECISION * (10**(srcDecimals - dstDecimals)));
        }
    }

    function calcSrcQty(uint dstQty, uint srcDecimals, uint dstDecimals, uint rate) internal pure returns(uint) {
        require(dstQty <= MAX_QTY);
        require(rate <= MAX_RATE);
        
        //source quantity is rounded up. to avoid dest quantity being too low.
        uint numerator;
        uint denominator;
        if (srcDecimals >= dstDecimals) {
            require((srcDecimals - dstDecimals) <= MAX_DECIMALS);
            numerator = (PRECISION * dstQty * (10**(srcDecimals - dstDecimals)));
            denominator = rate;
        } else {
            require((dstDecimals - srcDecimals) <= MAX_DECIMALS);
            numerator = (PRECISION * dstQty);
            denominator = (rate * (10**(dstDecimals - srcDecimals)));
        }
        return (numerator + denominator - 1) / denominator; //avoid rounding down errors
    }
}

// File: contracts/PermissionGroups.sol

pragma solidity 0.4.18;


contract PermissionGroups {

    address public admin;
    address public pendingAdmin;
    mapping(address=>bool) internal operators;
    mapping(address=>bool) internal alerters;
    address[] internal operatorsGroup;
    address[] internal alertersGroup;
    uint constant internal MAX_GROUP_SIZE = 50;

    function PermissionGroups() public {
        admin = msg.sender;
    }

    modifier onlyAdmin() {
        require(msg.sender == admin);
        _;
    }

    modifier onlyOperator() {
        require(operators[msg.sender]);
        _;
    }

    modifier onlyAlerter() {
        require(alerters[msg.sender]);
        _;
    }

    function getOperators () external view returns(address[]) {
        return operatorsGroup;
    }

    function getAlerters () external view returns(address[]) {
        return alertersGroup;
    }

    event TransferAdminPending(address pendingAdmin);

    /**
     * @dev Allows the current admin to set the pendingAdmin address.
     * @param newAdmin The address to transfer ownership to.
     */
    function transferAdmin(address newAdmin) public onlyAdmin {
        require(newAdmin != address(0));
        TransferAdminPending(pendingAdmin);
        pendingAdmin = newAdmin;
    }

    /**
     * @dev Allows the current admin to set the admin in one tx. Useful initial deployment.
     * @param newAdmin The address to transfer ownership to.
     */
    function transferAdminQuickly(address newAdmin) public onlyAdmin {
        require(newAdmin != address(0));
        TransferAdminPending(newAdmin);
        AdminClaimed(newAdmin, admin);
        admin = newAdmin;
    }

    event AdminClaimed( address newAdmin, address previousAdmin);

    /**
     * @dev Allows the pendingAdmin address to finalize the change admin process.
     */
    function claimAdmin() public {
        require(pendingAdmin == msg.sender);
        AdminClaimed(pendingAdmin, admin);
        admin = pendingAdmin;
        pendingAdmin = address(0);
    }

    event AlerterAdded (address newAlerter, bool isAdd);

    function addAlerter(address newAlerter) public onlyAdmin {
        require(!alerters[newAlerter]); // prevent duplicates.
        require(alertersGroup.length < MAX_GROUP_SIZE);

        AlerterAdded(newAlerter, true);
        alerters[newAlerter] = true;
        alertersGroup.push(newAlerter);
    }

    function removeAlerter (address alerter) public onlyAdmin {
        require(alerters[alerter]);
        alerters[alerter] = false;

        for (uint i = 0; i < alertersGroup.length; ++i) {
            if (alertersGroup[i] == alerter) {
                alertersGroup[i] = alertersGroup[alertersGroup.length - 1];
                alertersGroup.length--;
                AlerterAdded(alerter, false);
                break;
            }
        }
    }

    event OperatorAdded(address newOperator, bool isAdd);

    function addOperator(address newOperator) public onlyAdmin {
        require(!operators[newOperator]); // prevent duplicates.
        require(operatorsGroup.length < MAX_GROUP_SIZE);

        OperatorAdded(newOperator, true);
        operators[newOperator] = true;
        operatorsGroup.push(newOperator);
    }

    function removeOperator (address operator) public onlyAdmin {
        require(operators[operator]);
        operators[operator] = false;

        for (uint i = 0; i < operatorsGroup.length; ++i) {
            if (operatorsGroup[i] == operator) {
                operatorsGroup[i] = operatorsGroup[operatorsGroup.length - 1];
                operatorsGroup.length -= 1;
                OperatorAdded(operator, false);
                break;
            }
        }
    }
}

// File: contracts/Withdrawable.sol

pragma solidity 0.4.18;




/**
 * @title Contracts that should be able to recover tokens or ethers
 * @author Ilan Doron
 * @dev This allows to recover any tokens or Ethers received in a contract.
 * This will prevent any accidental loss of tokens.
 */
contract Withdrawable is PermissionGroups {

    event TokenWithdraw(ERC20 token, uint amount, address sendTo);

    /**
     * @dev Withdraw all ERC20 compatible tokens
     * @param token ERC20 The address of the token contract
     */
    function withdrawToken(ERC20 token, uint amount, address sendTo) external onlyAdmin {
        require(token.transfer(sendTo, amount));
        TokenWithdraw(token, amount, sendTo);
    }

    event EtherWithdraw(uint amount, address sendTo);

    /**
     * @dev Withdraw Ethers
     */
    function withdrawEther(uint amount, address sendTo) external onlyAdmin {
        sendTo.transfer(amount);
        EtherWithdraw(amount, sendTo);
    }
}

// File: contracts/ConversionRatesInterface.sol

pragma solidity 0.4.18;



interface ConversionRatesInterface {

    function recordImbalance(
        ERC20 token,
        int buyAmount,
        uint rateUpdateBlock,
        uint currentBlock
    )
        public;

    function getRate(ERC20 token, uint currentBlockNumber, bool buy, uint qty) public view returns(uint);
}

// File: contracts/SanityRatesInterface.sol

pragma solidity 0.4.18;


interface SanityRatesInterface {
    function getSanityRate(ERC20 src, ERC20 dest) public view returns(uint);
}

// File: contracts/KyberReserveInterface.sol

pragma solidity 0.4.18;


/// @title Kyber Reserve contract
interface KyberReserveInterface {

    function trade(
        ERC20 srcToken,
        uint srcAmount,
        ERC20 destToken,
        address destAddress,
        uint conversionRate,
        bool validate
    )
        public
        payable
        returns(bool);

    function getConversionRate(ERC20 src, ERC20 dest, uint srcQty, uint blockNumber) public view returns(uint);
}

// File: contracts/reserves/KyberReserve.sol

pragma solidity 0.4.18;








/// @title Kyber Reserve contract
contract KyberReserve is KyberReserveInterface, Withdrawable, Utils {

    address public kyberNetwork;
    bool public tradeEnabled;
    ConversionRatesInterface public conversionRatesContract;
    SanityRatesInterface public sanityRatesContract;
    mapping(bytes32=>bool) public approvedWithdrawAddresses; // sha3(token,address)=>bool
    mapping(address=>address) public tokenWallet;

    function KyberReserve(address _kyberNetwork, ConversionRatesInterface _ratesContract, address _admin) public {
        require(_admin != address(0));
        require(_ratesContract != address(0));
        require(_kyberNetwork != address(0));
        kyberNetwork = _kyberNetwork;
        conversionRatesContract = _ratesContract;
        admin = _admin;
        tradeEnabled = true;
    }

    event DepositToken(ERC20 token, uint amount);

    function() public payable {
        DepositToken(ETH_TOKEN_ADDRESS, msg.value);
    }

    event TradeExecute(
        address indexed origin,
        address src,
        uint srcAmount,
        address destToken,
        uint destAmount,
        address destAddress
    );

    function trade(
        ERC20 srcToken,
        uint srcAmount,
        ERC20 destToken,
        address destAddress,
        uint conversionRate,
        bool validate
    )
        public
        payable
        returns(bool)
    {
        require(tradeEnabled);
        require(msg.sender == kyberNetwork);

        require(doTrade(srcToken, srcAmount, destToken, destAddress, conversionRate, validate));

        return true;
    }

    event TradeEnabled(bool enable);

    function enableTrade() public onlyAdmin returns(bool) {
        tradeEnabled = true;
        TradeEnabled(true);

        return true;
    }

    function disableTrade() public onlyAlerter returns(bool) {
        tradeEnabled = false;
        TradeEnabled(false);

        return true;
    }

    event WithdrawAddressApproved(ERC20 token, address addr, bool approve);

    function approveWithdrawAddress(ERC20 token, address addr, bool approve) public onlyAdmin {
        approvedWithdrawAddresses[keccak256(token, addr)] = approve;
        WithdrawAddressApproved(token, addr, approve);

        setDecimals(token);
        if ((tokenWallet[token] == address(0x0)) && (token != ETH_TOKEN_ADDRESS)) {
            tokenWallet[token] = this; // by default
            require(token.approve(this, 2 ** 255));
        }
    }

    event NewTokenWallet(ERC20 token, address wallet);

    function setTokenWallet(ERC20 token, address wallet) public onlyAdmin {
        require(wallet != address(0x0));
        tokenWallet[token] = wallet;
        NewTokenWallet(token, wallet);
    }

    event WithdrawFunds(ERC20 token, uint amount, address destination);

    function withdraw(ERC20 token, uint amount, address destination) public onlyOperator returns(bool) {
        require(approvedWithdrawAddresses[keccak256(token, destination)]);

        if (token == ETH_TOKEN_ADDRESS) {
            destination.transfer(amount);
        } else {
            require(token.transferFrom(tokenWallet[token], destination, amount));
        }

        WithdrawFunds(token, amount, destination);

        return true;
    }

    event SetContractAddresses(address network, address rate, address sanity);

    function setContracts(
        address _kyberNetwork,
        ConversionRatesInterface _conversionRates,
        SanityRatesInterface _sanityRates
    )
        public
        onlyAdmin
    {
        require(_kyberNetwork != address(0));
        require(_conversionRates != address(0));

        kyberNetwork = _kyberNetwork;
        conversionRatesContract = _conversionRates;
        sanityRatesContract = _sanityRates;

        SetContractAddresses(kyberNetwork, conversionRatesContract, sanityRatesContract);
    }

    ////////////////////////////////////////////////////////////////////////////
    /// status functions ///////////////////////////////////////////////////////
    ////////////////////////////////////////////////////////////////////////////
    function getBalance(ERC20 token) public view returns(uint) {
        if (token == ETH_TOKEN_ADDRESS)
            return this.balance;
        else {
            address wallet = tokenWallet[token];
            uint balanceOfWallet = token.balanceOf(wallet);
            uint allowanceOfWallet = token.allowance(wallet, this);

            return (balanceOfWallet < allowanceOfWallet) ? balanceOfWallet : allowanceOfWallet;
        }
    }

    function getDestQty(ERC20 src, ERC20 dest, uint srcQty, uint rate) public view returns(uint) {
        uint dstDecimals = getDecimals(dest);
        uint srcDecimals = getDecimals(src);

        return calcDstQty(srcQty, srcDecimals, dstDecimals, rate);
    }

    function getSrcQty(ERC20 src, ERC20 dest, uint dstQty, uint rate) public view returns(uint) {
        uint dstDecimals = getDecimals(dest);
        uint srcDecimals = getDecimals(src);

        return calcSrcQty(dstQty, srcDecimals, dstDecimals, rate);
    }

    function getConversionRate(ERC20 src, ERC20 dest, uint srcQty, uint blockNumber) public view returns(uint) {
        ERC20 token;
        bool  isBuy;

        if (!tradeEnabled) return 0;

        if (ETH_TOKEN_ADDRESS == src) {
            isBuy = true;
            token = dest;
        } else if (ETH_TOKEN_ADDRESS == dest) {
            isBuy = false;
            token = src;
        } else {
            return 0; // pair is not listed
        }

        uint rate = conversionRatesContract.getRate(token, blockNumber, isBuy, srcQty);
        uint destQty = getDestQty(src, dest, srcQty, rate);

        if (getBalance(dest) < destQty) return 0;

        if (sanityRatesContract != address(0)) {
            uint sanityRate = sanityRatesContract.getSanityRate(src, dest);
            if (rate > sanityRate) return 0;
        }

        return rate;
    }

    /// @dev do a trade
    /// @param srcToken Src token
    /// @param srcAmount Amount of src token
    /// @param destToken Destination token
    /// @param destAddress Destination address to send tokens to
    /// @param validate If true, additional validations are applicable
    /// @return true iff trade is successful
    function doTrade(
        ERC20 srcToken,
        uint srcAmount,
        ERC20 destToken,
        address destAddress,
        uint conversionRate,
        bool validate
    )
        internal
        returns(bool)
    {
        // can skip validation if done at kyber network level
        if (validate) {
            require(conversionRate > 0);
            if (srcToken == ETH_TOKEN_ADDRESS)
                require(msg.value == srcAmount);
            else
                require(msg.value == 0);
        }

        uint destAmount = getDestQty(srcToken, destToken, srcAmount, conversionRate);
        // sanity check
        require(destAmount > 0);

        // add to imbalance
        ERC20 token;
        int tradeAmount;
        if (srcToken == ETH_TOKEN_ADDRESS) {
            tradeAmount = int(destAmount);
            token = destToken;
        } else {
            tradeAmount = -1 * int(srcAmount);
            token = srcToken;
        }

        conversionRatesContract.recordImbalance(
            token,
            tradeAmount,
            0,
            block.number
        );

        // collect src tokens
        if (srcToken != ETH_TOKEN_ADDRESS) {
            require(srcToken.transferFrom(msg.sender, tokenWallet[srcToken], srcAmount));
        }

        // send dest tokens
        if (destToken == ETH_TOKEN_ADDRESS) {
            destAddress.transfer(destAmount);
        } else {
            require(destToken.transferFrom(tokenWallet[destToken], destAddress, destAmount));
        }

        TradeExecute(msg.sender, srcToken, srcAmount, destToken, destAmount, destAddress);

        return true;
    }
}

{"ConversionRatesInterface.sol":{"content":"pragma solidity 0.4.18;\n\n\nimport \"./ERC20Interface.sol\";\n\n\ninterface ConversionRatesInterface {\n\n    function recordImbalance(\n        ERC20 token,\n        int buyAmount,\n        uint rateUpdateBlock,\n        uint currentBlock\n    )\n        public;\n\n    function getRate(ERC20 token, uint currentBlockNumber, bool buy, uint qty) public view returns(uint);\n}\n"},"ERC20Interface.sol":{"content":"pragma solidity 0.4.18;\n\n\n// https://github.com/ethereum/EIPs/issues/20\ninterface ERC20 {\n    function totalSupply() public view returns (uint supply);\n    function balanceOf(address _owner) public view returns (uint balance);\n    function transfer(address _to, uint _value) public returns (bool success);\n    function transferFrom(address _from, address _to, uint _value) public returns (bool success);\n    function approve(address _spender, uint _value) public returns (bool success);\n    function allowance(address _owner, address _spender) public view returns (uint remaining);\n    function decimals() public view returns(uint digits);\n    event Approval(address indexed _owner, address indexed _spender, uint _value);\n}\n"},"LiquidityConversionRates.sol":{"content":"pragma solidity 0.4.18;\n\n\nimport \"../../ConversionRatesInterface.sol\";\nimport \"../../Withdrawable.sol\";\nimport \"../../Utils.sol\";\nimport \"./LiquidityFormula.sol\";\n\n\ncontract LiquidityConversionRates is ConversionRatesInterface, LiquidityFormula, Withdrawable, Utils {\n\n    uint constant FORMULA_PRECISION_BITS = 40;\n\n    ERC20 public token;\n    address public reserveContract;\n\n    uint public numFpBits;\n    uint public formulaPrecision;\n\n    uint public rInFp;\n    uint public pMinInFp;\n\n    uint public maxEthCapBuyInFp;\n    uint public maxEthCapSellInFp;\n    uint public maxQtyInFp;\n\n    uint public feeInBps;\n    uint public collectedFeesInTwei = 0;\n\n    uint public maxBuyRateInPrecision;\n    uint public minBuyRateInPrecision;\n    uint public maxSellRateInPrecision;\n    uint public minSellRateInPrecision;\n\n    function LiquidityConversionRates(address _admin, ERC20 _token) public {\n        transferAdminQuickly(_admin);\n        token = _token;\n        setDecimals(token);\n        require(getDecimals(token) \u003c= MAX_DECIMALS);\n    }\n\n    event ReserveAddressSet(address reserve);\n\n    function setReserveAddress(address reserve) public onlyAdmin {\n        reserveContract = reserve;\n        ReserveAddressSet(reserve);\n    }\n\n    event LiquidityParamsSet(\n        uint rInFp,\n        uint pMinInFp,\n        uint numFpBits,\n        uint maxCapBuyInFp,\n        uint maxEthCapSellInFp,\n        uint feeInBps,\n        uint formulaPrecision,\n        uint maxQtyInFp,\n        uint maxBuyRateInPrecision,\n        uint minBuyRateInPrecision,\n        uint maxSellRateInPrecision,\n        uint minSellRateInPrecision\n    );\n\n    function setLiquidityParams(\n        uint _rInFp,\n        uint _pMinInFp,\n        uint _numFpBits,\n        uint _maxCapBuyInWei,\n        uint _maxCapSellInWei,\n        uint _feeInBps,\n        uint _maxTokenToEthRateInPrecision,\n        uint _minTokenToEthRateInPrecision\n    ) public onlyAdmin {\n        require(_numFpBits == FORMULA_PRECISION_BITS); // only used config, but keep in API\n        formulaPrecision = uint(1)\u003c\u003c_numFpBits; // require(formulaPrecision \u003c= MAX_QTY)\n        require(_feeInBps \u003c 10000);\n        require(_minTokenToEthRateInPrecision \u003c _maxTokenToEthRateInPrecision);\n        require(_minTokenToEthRateInPrecision \u003e 0);\n        require(_rInFp \u003e 0);\n        require(_pMinInFp \u003e 0);\n\n        rInFp = _rInFp;\n        pMinInFp = _pMinInFp;\n        maxQtyInFp = fromWeiToFp(MAX_QTY);\n        numFpBits = _numFpBits;\n        maxEthCapBuyInFp = fromWeiToFp(_maxCapBuyInWei);\n        maxEthCapSellInFp = fromWeiToFp(_maxCapSellInWei);\n        feeInBps = _feeInBps;\n        maxBuyRateInPrecision = PRECISION * PRECISION / _minTokenToEthRateInPrecision;\n        minBuyRateInPrecision = PRECISION * PRECISION / _maxTokenToEthRateInPrecision;\n        maxSellRateInPrecision = _maxTokenToEthRateInPrecision;\n        minSellRateInPrecision = _minTokenToEthRateInPrecision;\n\n        LiquidityParamsSet(\n            rInFp,\n            pMinInFp,\n            numFpBits,\n            maxEthCapBuyInFp,\n            maxEthCapSellInFp,\n            feeInBps,\n            formulaPrecision,\n            maxQtyInFp,\n            maxBuyRateInPrecision,\n            minBuyRateInPrecision,\n            maxSellRateInPrecision,\n            minSellRateInPrecision\n        );\n    }\n\n    function recordImbalance(\n        ERC20 conversionToken,\n        int buyAmountInTwei,\n        uint rateUpdateBlock,\n        uint currentBlock\n    )\n        public\n    {\n        conversionToken;\n        rateUpdateBlock;\n        currentBlock;\n\n        require(msg.sender == reserveContract);\n        if (buyAmountInTwei \u003e 0) {\n            // Buy case\n            collectedFeesInTwei += calcCollectedFee(abs(buyAmountInTwei));\n        } else {\n            // Sell case\n            collectedFeesInTwei += abs(buyAmountInTwei) * feeInBps / 10000;\n        }\n    }\n\n    event CollectedFeesReset(uint resetFeesInTwei);\n\n    function resetCollectedFees() public onlyAdmin {\n        uint resetFeesInTwei = collectedFeesInTwei;\n        collectedFeesInTwei = 0;\n\n        CollectedFeesReset(resetFeesInTwei);\n    }\n\n    function getRate(\n            ERC20 conversionToken,\n            uint currentBlockNumber,\n            bool buy,\n            uint qtyInSrcWei\n    ) public view returns(uint) {\n\n        currentBlockNumber;\n\n        require(qtyInSrcWei \u003c= MAX_QTY);\n        uint eInFp = fromWeiToFp(reserveContract.balance);\n        uint rateInPrecision = getRateWithE(conversionToken, buy, qtyInSrcWei, eInFp);\n        require(rateInPrecision \u003c= MAX_RATE);\n        return rateInPrecision;\n    }\n\n    function getRateWithE(ERC20 conversionToken, bool buy, uint qtyInSrcWei, uint eInFp) public view returns(uint) {\n        uint deltaEInFp;\n        uint sellInputTokenQtyInFp;\n        uint deltaTInFp;\n        uint rateInPrecision;\n\n        require(qtyInSrcWei \u003c= MAX_QTY);\n        require(eInFp \u003c= maxQtyInFp);\n        if (conversionToken != token) return 0;\n\n        if (buy) {\n            // ETH goes in, token goes out\n            deltaEInFp = fromWeiToFp(qtyInSrcWei);\n            if (deltaEInFp \u003e maxEthCapBuyInFp) return 0;\n\n            if (deltaEInFp == 0) {\n                rateInPrecision = buyRateZeroQuantity(eInFp);\n            } else {\n                rateInPrecision = buyRate(eInFp, deltaEInFp);\n            }\n        } else {\n            sellInputTokenQtyInFp = fromTweiToFp(qtyInSrcWei);\n            deltaTInFp = valueAfterReducingFee(sellInputTokenQtyInFp);\n            if (deltaTInFp == 0) {\n                rateInPrecision = sellRateZeroQuantity(eInFp);\n                deltaEInFp = 0;\n            } else {\n                (rateInPrecision, deltaEInFp) = sellRate(eInFp, sellInputTokenQtyInFp, deltaTInFp);\n            }\n\n            if (deltaEInFp \u003e maxEthCapSellInFp) return 0;\n        }\n\n        rateInPrecision = rateAfterValidation(rateInPrecision, buy);\n        return rateInPrecision;\n    }\n\n    function rateAfterValidation(uint rateInPrecision, bool buy) public view returns(uint) {\n        uint minAllowRateInPrecision;\n        uint maxAllowedRateInPrecision;\n\n        if (buy) {\n            minAllowRateInPrecision = minBuyRateInPrecision;\n            maxAllowedRateInPrecision = maxBuyRateInPrecision;\n        } else {\n            minAllowRateInPrecision = minSellRateInPrecision;\n            maxAllowedRateInPrecision = maxSellRateInPrecision;\n        }\n\n        if ((rateInPrecision \u003e maxAllowedRateInPrecision) || (rateInPrecision \u003c minAllowRateInPrecision)) {\n            return 0;\n        } else if (rateInPrecision \u003e MAX_RATE) {\n            return 0;\n        } else {\n            return rateInPrecision;\n        }\n    }\n\n    function buyRate(uint eInFp, uint deltaEInFp) public view returns(uint) {\n        uint deltaTInFp = deltaTFunc(rInFp, pMinInFp, eInFp, deltaEInFp, formulaPrecision);\n        require(deltaTInFp \u003c= maxQtyInFp);\n        deltaTInFp = valueAfterReducingFee(deltaTInFp);\n        return deltaTInFp * PRECISION / deltaEInFp;\n    }\n\n    function buyRateZeroQuantity(uint eInFp) public view returns(uint) {\n        uint ratePreReductionInPrecision = formulaPrecision * PRECISION / pE(rInFp, pMinInFp, eInFp, formulaPrecision);\n        return valueAfterReducingFee(ratePreReductionInPrecision);\n    }\n\n    function sellRate(\n        uint eInFp,\n        uint sellInputTokenQtyInFp,\n        uint deltaTInFp\n    ) public view returns(uint rateInPrecision, uint deltaEInFp) {\n        deltaEInFp = deltaEFunc(rInFp, pMinInFp, eInFp, deltaTInFp, formulaPrecision, numFpBits);\n        require(deltaEInFp \u003c= maxQtyInFp);\n        rateInPrecision = deltaEInFp * PRECISION / sellInputTokenQtyInFp;\n    }\n\n    function sellRateZeroQuantity(uint eInFp) public view returns(uint) {\n        uint ratePreReductionInPrecision = pE(rInFp, pMinInFp, eInFp, formulaPrecision) * PRECISION / formulaPrecision;\n        return valueAfterReducingFee(ratePreReductionInPrecision);\n    }\n\n    function fromTweiToFp(uint qtyInTwei) public view returns(uint) {\n        require(qtyInTwei \u003c= MAX_QTY);\n        return qtyInTwei * formulaPrecision / (10 ** getDecimals(token));\n    }\n\n    function fromWeiToFp(uint qtyInwei) public view returns(uint) {\n        require(qtyInwei \u003c= MAX_QTY);\n        return qtyInwei * formulaPrecision / (10 ** ETH_DECIMALS);\n    }\n\n    function valueAfterReducingFee(uint val) public view returns(uint) {\n        require(val \u003c= BIG_NUMBER);\n        return ((10000 - feeInBps) * val) / 10000;\n    }\n\n    function calcCollectedFee(uint val) public view returns(uint) {\n        require(val \u003c= MAX_QTY);\n        return val * feeInBps / (10000 - feeInBps);\n    }\n\n    function abs(int val) public pure returns(uint) {\n        if (val \u003c 0) {\n            return uint(val * (-1));\n        } else {\n            return uint(val);\n        }\n    }\n}\n"},"LiquidityFormula.sol":{"content":"pragma solidity 0.4.18;\n\n\ncontract UtilMath {\n    uint public constant BIG_NUMBER = (uint(1)\u003c\u003cuint(200));\n\n    function checkMultOverflow(uint x, uint y) public pure returns(bool) {\n        if (y == 0) return false;\n        return (((x*y) / y) != x);\n    }\n\n    function compactFraction(uint p, uint q, uint precision) public pure returns (uint, uint) {\n        if (q \u003c precision * precision) return (p, q);\n        return compactFraction(p/precision, q/precision, precision);\n    }\n\n    /* solhint-disable code-complexity */\n    function exp(uint p, uint q, uint precision) public pure returns (uint) {\n        uint n = 0;\n        uint nFact = 1;\n        uint currentP = 1;\n        uint currentQ = 1;\n\n        uint sum = 0;\n        uint prevSum = 0;\n\n        while (true) {\n            if (checkMultOverflow(currentP, precision)) return sum;\n            if (checkMultOverflow(currentQ, nFact)) return sum;\n\n            sum += (currentP * precision) / (currentQ * nFact);\n\n            if (sum == prevSum) return sum;\n            prevSum = sum;\n\n            n++;\n\n            if (checkMultOverflow(currentP, p)) return sum;\n            if (checkMultOverflow(currentQ, q)) return sum;\n            if (checkMultOverflow(nFact, n)) return sum;\n\n            currentP *= p;\n            currentQ *= q;\n            nFact *= n;\n\n            (currentP, currentQ) = compactFraction(currentP, currentQ, precision);\n        }\n    }\n    /* solhint-enable code-complexity */\n\n    function countLeadingZeros(uint p, uint q) public pure returns (uint) {\n        uint denomator = (uint(1)\u003c\u003c255);\n        for (int i = 255; i \u003e= 0; i--) {\n            if ((q*denomator)/denomator != q) {\n                // overflow\n                denomator = denomator/2;\n                continue;\n            }\n            if (p/(q*denomator) \u003e 0) return uint(i);\n            denomator = denomator/2;\n        }\n\n        return uint(-1);\n    }\n\n    // log2 for a number that it in [1,2)\n    function log2ForSmallNumber(uint x, uint numPrecisionBits) public pure returns (uint) {\n        uint res = 0;\n        uint one = (uint(1)\u003c\u003cnumPrecisionBits);\n        uint two = 2 * one;\n        uint addition = one;\n\n        require((x \u003e= one) \u0026\u0026 (x \u003c= two));\n        require(numPrecisionBits \u003c 125);\n\n        for (uint i = numPrecisionBits; i \u003e 0; i--) {\n            x = (x*x) / one;\n            addition = addition/2;\n            if (x \u003e= two) {\n                x = x/2;\n                res += addition;\n            }\n        }\n\n        return res;\n    }\n\n    function logBase2 (uint p, uint q, uint numPrecisionBits) public pure returns (uint) {\n        uint n = 0;\n        uint precision = (uint(1)\u003c\u003cnumPrecisionBits);\n\n        if (p \u003e q) {\n            n = countLeadingZeros(p, q);\n        }\n\n        require(!checkMultOverflow(p, precision));\n        require(!checkMultOverflow(n, precision));\n        require(!checkMultOverflow(uint(1)\u003c\u003cn, q));\n\n        uint y = p * precision / (q * (uint(1)\u003c\u003cn));\n        uint log2Small = log2ForSmallNumber(y, numPrecisionBits);\n\n        require(n*precision \u003c= BIG_NUMBER);\n        require(log2Small \u003c= BIG_NUMBER);\n\n        return n * precision + log2Small;\n    }\n\n    function ln(uint p, uint q, uint numPrecisionBits) public pure returns (uint) {\n        uint ln2Numerator   = 6931471805599453094172;\n        uint ln2Denomerator = 10000000000000000000000;\n\n        uint log2x = logBase2(p, q, numPrecisionBits);\n\n        require(!checkMultOverflow(ln2Numerator, log2x));\n\n        return ln2Numerator * log2x / ln2Denomerator;\n    }\n}\n\n\ncontract LiquidityFormula is UtilMath {\n    function pE(uint r, uint pMIn, uint e, uint precision) public pure returns (uint) {\n        require(!checkMultOverflow(r, e));\n        uint expRE = exp(r*e, precision*precision, precision);\n        require(!checkMultOverflow(expRE, pMIn));\n        return pMIn*expRE / precision;\n    }\n\n    function deltaTFunc(uint r, uint pMIn, uint e, uint deltaE, uint precision) public pure returns (uint) {\n        uint pe = pE(r, pMIn, e, precision);\n        uint rpe = r * pe;\n\n        require(!checkMultOverflow(r, deltaE));\n        uint erdeltaE = exp(r*deltaE, precision*precision, precision);\n\n        require(erdeltaE \u003e= precision);\n        require(!checkMultOverflow(erdeltaE - precision, precision));\n        require(!checkMultOverflow((erdeltaE - precision)*precision, precision));\n        require(!checkMultOverflow((erdeltaE - precision)*precision*precision, precision));\n        require(!checkMultOverflow(rpe, erdeltaE));\n        require(!checkMultOverflow(r, pe));\n\n        return (erdeltaE - precision) * precision * precision * precision / (rpe*erdeltaE);\n    }\n\n    function deltaEFunc(uint r, uint pMIn, uint e, uint deltaT, uint precision, uint numPrecisionBits)\n        public pure\n        returns (uint)\n    {\n        uint pe = pE(r, pMIn, e, precision);\n        uint rpe = r * pe;\n\n        require(!checkMultOverflow(rpe, deltaT));\n        require(precision * precision + rpe * deltaT/precision \u003e precision * precision);\n        uint lnPart = ln(precision*precision + rpe*deltaT/precision, precision*precision, numPrecisionBits);\n\n        require(!checkMultOverflow(r, pe));\n        require(!checkMultOverflow(precision, precision));\n        require(!checkMultOverflow(rpe, deltaT));\n        require(!checkMultOverflow(lnPart, precision));\n\n        return lnPart * precision / r;\n    }\n}\n"},"PermissionGroups.sol":{"content":"pragma solidity 0.4.18;\n\n\ncontract PermissionGroups {\n\n    address public admin;\n    address public pendingAdmin;\n    mapping(address=\u003ebool) internal operators;\n    mapping(address=\u003ebool) internal alerters;\n    address[] internal operatorsGroup;\n    address[] internal alertersGroup;\n    uint constant internal MAX_GROUP_SIZE = 50;\n\n    function PermissionGroups() public {\n        admin = msg.sender;\n    }\n\n    modifier onlyAdmin() {\n        require(msg.sender == admin);\n        _;\n    }\n\n    modifier onlyOperator() {\n        require(operators[msg.sender]);\n        _;\n    }\n\n    modifier onlyAlerter() {\n        require(alerters[msg.sender]);\n        _;\n    }\n\n    function getOperators () external view returns(address[]) {\n        return operatorsGroup;\n    }\n\n    function getAlerters () external view returns(address[]) {\n        return alertersGroup;\n    }\n\n    event TransferAdminPending(address pendingAdmin);\n\n    /**\n     * @dev Allows the current admin to set the pendingAdmin address.\n     * @param newAdmin The address to transfer ownership to.\n     */\n    function transferAdmin(address newAdmin) public onlyAdmin {\n        require(newAdmin != address(0));\n        TransferAdminPending(pendingAdmin);\n        pendingAdmin = newAdmin;\n    }\n\n    /**\n     * @dev Allows the current admin to set the admin in one tx. Useful initial deployment.\n     * @param newAdmin The address to transfer ownership to.\n     */\n    function transferAdminQuickly(address newAdmin) public onlyAdmin {\n        require(newAdmin != address(0));\n        TransferAdminPending(newAdmin);\n        AdminClaimed(newAdmin, admin);\n        admin = newAdmin;\n    }\n\n    event AdminClaimed( address newAdmin, address previousAdmin);\n\n    /**\n     * @dev Allows the pendingAdmin address to finalize the change admin process.\n     */\n    function claimAdmin() public {\n        require(pendingAdmin == msg.sender);\n        AdminClaimed(pendingAdmin, admin);\n        admin = pendingAdmin;\n        pendingAdmin = address(0);\n    }\n\n    event AlerterAdded (address newAlerter, bool isAdd);\n\n    function addAlerter(address newAlerter) public onlyAdmin {\n        require(!alerters[newAlerter]); // prevent duplicates.\n        require(alertersGroup.length \u003c MAX_GROUP_SIZE);\n\n        AlerterAdded(newAlerter, true);\n        alerters[newAlerter] = true;\n        alertersGroup.push(newAlerter);\n    }\n\n    function removeAlerter (address alerter) public onlyAdmin {\n        require(alerters[alerter]);\n        alerters[alerter] = false;\n\n        for (uint i = 0; i \u003c alertersGroup.length; ++i) {\n            if (alertersGroup[i] == alerter) {\n                alertersGroup[i] = alertersGroup[alertersGroup.length - 1];\n                alertersGroup.length--;\n                AlerterAdded(alerter, false);\n                break;\n            }\n        }\n    }\n\n    event OperatorAdded(address newOperator, bool isAdd);\n\n    function addOperator(address newOperator) public onlyAdmin {\n        require(!operators[newOperator]); // prevent duplicates.\n        require(operatorsGroup.length \u003c MAX_GROUP_SIZE);\n\n        OperatorAdded(newOperator, true);\n        operators[newOperator] = true;\n        operatorsGroup.push(newOperator);\n    }\n\n    function removeOperator (address operator) public onlyAdmin {\n        require(operators[operator]);\n        operators[operator] = false;\n\n        for (uint i = 0; i \u003c operatorsGroup.length; ++i) {\n            if (operatorsGroup[i] == operator) {\n                operatorsGroup[i] = operatorsGroup[operatorsGroup.length - 1];\n                operatorsGroup.length -= 1;\n                OperatorAdded(operator, false);\n                break;\n            }\n        }\n    }\n}\n"},"Utils.sol":{"content":"pragma solidity 0.4.18;\n\n\nimport \"./ERC20Interface.sol\";\n\n\n/// @title Kyber constants contract\ncontract Utils {\n\n    ERC20 constant internal ETH_TOKEN_ADDRESS = ERC20(0x00eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee);\n    uint  constant internal PRECISION = (10**18);\n    uint  constant internal MAX_QTY   = (10**28); // 10B tokens\n    uint  constant internal MAX_RATE  = (PRECISION * 10**6); // up to 1M tokens per ETH\n    uint  constant internal MAX_DECIMALS = 18;\n    uint  constant internal ETH_DECIMALS = 18;\n    mapping(address=\u003euint) internal decimals;\n\n    function setDecimals(ERC20 token) internal {\n        if (token == ETH_TOKEN_ADDRESS) decimals[token] = ETH_DECIMALS;\n        else decimals[token] = token.decimals();\n    }\n\n    function getDecimals(ERC20 token) internal view returns(uint) {\n        if (token == ETH_TOKEN_ADDRESS) return ETH_DECIMALS; // save storage access\n        uint tokenDecimals = decimals[token];\n        // technically, there might be token with decimals 0\n        // moreover, very possible that old tokens have decimals 0\n        // these tokens will just have higher gas fees.\n        if(tokenDecimals == 0) return token.decimals();\n\n        return tokenDecimals;\n    }\n\n    function calcDstQty(uint srcQty, uint srcDecimals, uint dstDecimals, uint rate) internal pure returns(uint) {\n        require(srcQty \u003c= MAX_QTY);\n        require(rate \u003c= MAX_RATE);\n\n        if (dstDecimals \u003e= srcDecimals) {\n            require((dstDecimals - srcDecimals) \u003c= MAX_DECIMALS);\n            return (srcQty * rate * (10**(dstDecimals - srcDecimals))) / PRECISION;\n        } else {\n            require((srcDecimals - dstDecimals) \u003c= MAX_DECIMALS);\n            return (srcQty * rate) / (PRECISION * (10**(srcDecimals - dstDecimals)));\n        }\n    }\n\n    function calcSrcQty(uint dstQty, uint srcDecimals, uint dstDecimals, uint rate) internal pure returns(uint) {\n        require(dstQty \u003c= MAX_QTY);\n        require(rate \u003c= MAX_RATE);\n        \n        //source quantity is rounded up. to avoid dest quantity being too low.\n        uint numerator;\n        uint denominator;\n        if (srcDecimals \u003e= dstDecimals) {\n            require((srcDecimals - dstDecimals) \u003c= MAX_DECIMALS);\n            numerator = (PRECISION * dstQty * (10**(srcDecimals - dstDecimals)));\n            denominator = rate;\n        } else {\n            require((dstDecimals - srcDecimals) \u003c= MAX_DECIMALS);\n            numerator = (PRECISION * dstQty);\n            denominator = (rate * (10**(dstDecimals - srcDecimals)));\n        }\n        return (numerator + denominator - 1) / denominator; //avoid rounding down errors\n    }\n}\n"},"Withdrawable.sol":{"content":"pragma solidity 0.4.18;\n\n\nimport \"./ERC20Interface.sol\";\nimport \"./PermissionGroups.sol\";\n\n\n/**\n * @title Contracts that should be able to recover tokens or ethers\n * @author Ilan Doron\n * @dev This allows to recover any tokens or Ethers received in a contract.\n * This will prevent any accidental loss of tokens.\n */\ncontract Withdrawable is PermissionGroups {\n\n    event TokenWithdraw(ERC20 token, uint amount, address sendTo);\n\n    /**\n     * @dev Withdraw all ERC20 compatible tokens\n     * @param token ERC20 The address of the token contract\n     */\n    function withdrawToken(ERC20 token, uint amount, address sendTo) external onlyAdmin {\n        require(token.transfer(sendTo, amount));\n        TokenWithdraw(token, amount, sendTo);\n    }\n\n    event EtherWithdraw(uint amount, address sendTo);\n\n    /**\n     * @dev Withdraw Ethers\n     */\n    function withdrawEther(uint amount, address sendTo) external onlyAdmin {\n        sendTo.transfer(amount);\n        EtherWithdraw(amount, sendTo);\n    }\n}\n"}}

pragma solidity 0.4.15;

contract RegistryICAPInterface {
    function parse(bytes32 _icap) constant returns(address, bytes32, bool);
    function institutions(bytes32 _institution) constant returns(address);
}

contract EToken2Interface {
    function registryICAP() constant returns(RegistryICAPInterface);
    function baseUnit(bytes32 _symbol) constant returns(uint8);
    function description(bytes32 _symbol) constant returns(string);
    function owner(bytes32 _symbol) constant returns(address);
    function isOwner(address _owner, bytes32 _symbol) constant returns(bool);
    function totalSupply(bytes32 _symbol) constant returns(uint);
    function balanceOf(address _holder, bytes32 _symbol) constant returns(uint);
    function isLocked(bytes32 _symbol) constant returns(bool);
    function issueAsset(bytes32 _symbol, uint _value, string _name, string _description, uint8 _baseUnit, bool _isReissuable) returns(bool);
    function reissueAsset(bytes32 _symbol, uint _value) returns(bool);
    function revokeAsset(bytes32 _symbol, uint _value) returns(bool);
    function setProxy(address _address, bytes32 _symbol) returns(bool);
    function lockAsset(bytes32 _symbol) returns(bool);
    function proxyTransferFromToICAPWithReference(address _from, bytes32 _icap, uint _value, string _reference, address _sender) returns(bool);
    function proxyApprove(address _spender, uint _value, bytes32 _symbol, address _sender) returns(bool);
    function allowance(address _from, address _spender, bytes32 _symbol) constant returns(uint);
    function proxyTransferFromWithReference(address _from, address _to, uint _value, bytes32 _symbol, string _reference, address _sender) returns(bool);
}

contract AssetInterface {
    function _performTransferWithReference(address _to, uint _value, string _reference, address _sender) returns(bool);
    function _performTransferToICAPWithReference(bytes32 _icap, uint _value, string _reference, address _sender) returns(bool);
    function _performApprove(address _spender, uint _value, address _sender) returns(bool);    
    function _performTransferFromWithReference(address _from, address _to, uint _value, string _reference, address _sender) returns(bool);
    function _performTransferFromToICAPWithReference(address _from, bytes32 _icap, uint _value, string _reference, address _sender) returns(bool);
    function _performGeneric(bytes, address) payable {
        revert();
    }
}

contract ERC20Interface {
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed from, address indexed spender, uint256 value);

    function totalSupply() constant returns(uint256 supply);
    function balanceOf(address _owner) constant returns(uint256 balance);
    function transfer(address _to, uint256 _value) returns(bool success);
    function transferFrom(address _from, address _to, uint256 _value) returns(bool success);
    function approve(address _spender, uint256 _value) returns(bool success);
    function allowance(address _owner, address _spender) constant returns(uint256 remaining);

    // function symbol() constant returns(string);
    function decimals() constant returns(uint8);
    // function name() constant returns(string);
}

contract AssetProxyInterface {
    function _forwardApprove(address _spender, uint _value, address _sender) returns(bool);
    function _forwardTransferFromWithReference(address _from, address _to, uint _value, string _reference, address _sender) returns(bool);
    function _forwardTransferFromToICAPWithReference(address _from, bytes32 _icap, uint _value, string _reference, address _sender) returns(bool);
    function balanceOf(address _owner) constant returns(uint);
}

contract Bytes32 {
    function _bytes32(string _input) internal constant returns(bytes32 result) {
        assembly {
            result := mload(add(_input, 32))
        }
    }
}

contract ReturnData {
    function _returnReturnData(bool _success) internal {
        assembly {
            let returndatastart := msize()
            mstore(0x40, add(returndatastart, returndatasize))
            returndatacopy(returndatastart, 0, returndatasize)
            switch _success case 0 { revert(returndatastart, returndatasize) } default { return(returndatastart, returndatasize) }
        }
    }

    function _assemblyCall(address _destination, uint _value, bytes _data) internal returns(bool success) {
        assembly {
            success := call(div(mul(gas, 63), 64), _destination, _value, add(_data, 32), mload(_data), 0, 0)
        }
    }
}

/**
 * @title EToken2 Asset Proxy.
 *
 * Proxy implements ERC20 interface and acts as a gateway to a single EToken2 asset.
 * Proxy adds etoken2Symbol and caller(sender) when forwarding requests to EToken2.
 * Every request that is made by caller first sent to the specific asset implementation
 * contract, which then calls back to be forwarded onto EToken2.
 *
 * Calls flow: Caller ->
 *             Proxy.func(...) ->
 *             Asset._performFunc(..., Caller.address) ->
 *             Proxy._forwardFunc(..., Caller.address) ->
 *             Platform.proxyFunc(..., symbol, Caller.address)
 *
 * Generic call flow: Caller ->
 *             Proxy.unknownFunc(...) ->
 *             Asset._performGeneric(..., Caller.address) ->
 *             Asset.unknownFunc(...)
 *
 * Asset implementation contract is mutable, but each user have an option to stick with
 * old implementation, through explicit decision made in timely manner, if he doesn't agree
 * with new rules.
 * Each user have a possibility to upgrade to latest asset contract implementation, without the
 * possibility to rollback.
 *
 * Note: all the non constant functions return false instead of throwing in case if state change
 * didn't happen yet.
 */
contract AssetProxy is ERC20Interface, AssetProxyInterface, Bytes32, ReturnData {
    // Assigned EToken2, immutable.
    EToken2Interface public etoken2;

    // Assigned symbol, immutable.
    bytes32 public etoken2Symbol;

    // Assigned name, immutable. For UI.
    string public name;
    string public symbol;

    /**
     * Sets EToken2 address, assigns symbol and name.
     *
     * Can be set only once.
     *
     * @param _etoken2 EToken2 contract address.
     * @param _symbol assigned symbol.
     * @param _name assigned name.
     *
     * @return success.
     */
    function init(EToken2Interface _etoken2, string _symbol, string _name) returns(bool) {
        if (address(etoken2) != 0x0) {
            return false;
        }
        etoken2 = _etoken2;
        etoken2Symbol = _bytes32(_symbol);
        name = _name;
        symbol = _symbol;
        return true;
    }

    /**
     * Only EToken2 is allowed to call.
     */
    modifier onlyEToken2() {
        if (msg.sender == address(etoken2)) {
            _;
        }
    }

    /**
     * Only current asset owner is allowed to call.
     */
    modifier onlyAssetOwner() {
        if (etoken2.isOwner(msg.sender, etoken2Symbol)) {
            _;
        }
    }

    /**
     * Returns asset implementation contract for current caller.
     *
     * @return asset implementation contract.
     */
    function _getAsset() internal returns(AssetInterface) {
        return AssetInterface(getVersionFor(msg.sender));
    }

    function recoverTokens(uint _value) onlyAssetOwner() returns(bool) {
        return this.transferWithReference(msg.sender, _value, 'Tokens recovery');
    }

    /**
     * Returns asset total supply.
     *
     * @return asset total supply.
     */
    function totalSupply() constant returns(uint) {
        return etoken2.totalSupply(etoken2Symbol);
    }

    /**
     * Returns asset balance for a particular holder.
     *
     * @param _owner holder address.
     *
     * @return holder balance.
     */
    function balanceOf(address _owner) constant returns(uint) {
        return etoken2.balanceOf(_owner, etoken2Symbol);
    }

    /**
     * Returns asset allowance from one holder to another.
     *
     * @param _from holder that allowed spending.
     * @param _spender holder that is allowed to spend.
     *
     * @return holder to spender allowance.
     */
    function allowance(address _from, address _spender) constant returns(uint) {
        return etoken2.allowance(_from, _spender, etoken2Symbol);
    }

    /**
     * Returns asset decimals.
     *
     * @return asset decimals.
     */
    function decimals() constant returns(uint8) {
        return etoken2.baseUnit(etoken2Symbol);
    }

    /**
     * Transfers asset balance from the caller to specified receiver.
     *
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     *
     * @return success.
     */
    function transfer(address _to, uint _value) returns(bool) {
        return transferWithReference(_to, _value, '');
    }

    /**
     * Transfers asset balance from the caller to specified receiver adding specified comment.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     *
     * @return success.
     */
    function transferWithReference(address _to, uint _value, string _reference) returns(bool) {
        return _getAsset()._performTransferWithReference(_to, _value, _reference, msg.sender);
    }

    /**
     * Transfers asset balance from the caller to specified ICAP.
     *
     * @param _icap recipient ICAP to give to.
     * @param _value amount to transfer.
     *
     * @return success.
     */
    function transferToICAP(bytes32 _icap, uint _value) returns(bool) {
        return transferToICAPWithReference(_icap, _value, '');
    }

    /**
     * Transfers asset balance from the caller to specified ICAP adding specified comment.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _icap recipient ICAP to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     *
     * @return success.
     */
    function transferToICAPWithReference(bytes32 _icap, uint _value, string _reference) returns(bool) {
        return _getAsset()._performTransferToICAPWithReference(_icap, _value, _reference, msg.sender);
    }

    /**
     * Prforms allowance transfer of asset balance between holders.
     *
     * @param _from holder address to take from.
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     *
     * @return success.
     */
    function transferFrom(address _from, address _to, uint _value) returns(bool) {
        return transferFromWithReference(_from, _to, _value, '');
    }

    /**
     * Prforms allowance transfer of asset balance between holders adding specified comment.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _from holder address to take from.
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     *
     * @return success.
     */
    function transferFromWithReference(address _from, address _to, uint _value, string _reference) returns(bool) {
        return _getAsset()._performTransferFromWithReference(_from, _to, _value, _reference, msg.sender);
    }

    /**
     * Performs transfer call on the EToken2 by the name of specified sender.
     *
     * Can only be called by asset implementation contract assigned to sender.
     *
     * @param _from holder address to take from.
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     * @param _sender initial caller.
     *
     * @return success.
     */
    function _forwardTransferFromWithReference(address _from, address _to, uint _value, string _reference, address _sender) onlyImplementationFor(_sender) returns(bool) {
        return etoken2.proxyTransferFromWithReference(_from, _to, _value, etoken2Symbol, _reference, _sender);
    }

    /**
     * Prforms allowance transfer of asset balance between holders.
     *
     * @param _from holder address to take from.
     * @param _icap recipient ICAP address to give to.
     * @param _value amount to transfer.
     *
     * @return success.
     */
    function transferFromToICAP(address _from, bytes32 _icap, uint _value) returns(bool) {
        return transferFromToICAPWithReference(_from, _icap, _value, '');
    }

    /**
     * Prforms allowance transfer of asset balance between holders adding specified comment.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _from holder address to take from.
     * @param _icap recipient ICAP address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     *
     * @return success.
     */
    function transferFromToICAPWithReference(address _from, bytes32 _icap, uint _value, string _reference) returns(bool) {
        return _getAsset()._performTransferFromToICAPWithReference(_from, _icap, _value, _reference, msg.sender);
    }

    /**
     * Performs allowance transfer to ICAP call on the EToken2 by the name of specified sender.
     *
     * Can only be called by asset implementation contract assigned to sender.
     *
     * @param _from holder address to take from.
     * @param _icap recipient ICAP address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     * @param _sender initial caller.
     *
     * @return success.
     */
    function _forwardTransferFromToICAPWithReference(address _from, bytes32 _icap, uint _value, string _reference, address _sender) onlyImplementationFor(_sender) returns(bool) {
        return etoken2.proxyTransferFromToICAPWithReference(_from, _icap, _value, _reference, _sender);
    }

    /**
     * Sets asset spending allowance for a specified spender.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _spender holder address to set allowance to.
     * @param _value amount to allow.
     *
     * @return success.
     */
    function approve(address _spender, uint _value) returns(bool) {
        return _getAsset()._performApprove(_spender, _value, msg.sender);
    }

    /**
     * Performs allowance setting call on the EToken2 by the name of specified sender.
     *
     * Can only be called by asset implementation contract assigned to sender.
     *
     * @param _spender holder address to set allowance to.
     * @param _value amount to allow.
     * @param _sender initial caller.
     *
     * @return success.
     */
    function _forwardApprove(address _spender, uint _value, address _sender) onlyImplementationFor(_sender) returns(bool) {
        return etoken2.proxyApprove(_spender, _value, etoken2Symbol, _sender);
    }

    /**
     * Emits ERC20 Transfer event on this contract.
     *
     * Can only be, and, called by assigned EToken2 when asset transfer happens.
     */
    function emitTransfer(address _from, address _to, uint _value) onlyEToken2() {
        Transfer(_from, _to, _value);
    }

    /**
     * Emits ERC20 Approval event on this contract.
     *
     * Can only be, and, called by assigned EToken2 when asset allowance set happens.
     */
    function emitApprove(address _from, address _spender, uint _value) onlyEToken2() {
        Approval(_from, _spender, _value);
    }

    /**
     * Resolves asset implementation contract for the caller and forwards there transaction data,
     * along with the value. This allows for proxy interface growth.
     */
    function () payable {
        _getAsset()._performGeneric.value(msg.value)(msg.data, msg.sender);
        _returnReturnData(true);
    }

    // Interface functions to allow specifying ICAP addresses as strings.
    function transferToICAP(string _icap, uint _value) returns(bool) {
        return transferToICAPWithReference(_icap, _value, '');
    }

    function transferToICAPWithReference(string _icap, uint _value, string _reference) returns(bool) {
        return transferToICAPWithReference(_bytes32(_icap), _value, _reference);
    }

    function transferFromToICAP(address _from, string _icap, uint _value) returns(bool) {
        return transferFromToICAPWithReference(_from, _icap, _value, '');
    }

    function transferFromToICAPWithReference(address _from, string _icap, uint _value, string _reference) returns(bool) {
        return transferFromToICAPWithReference(_from, _bytes32(_icap), _value, _reference);
    }

    /**
     * Indicates an upgrade freeze-time start, and the next asset implementation contract.
     */
    event UpgradeProposal(address newVersion);

    // Current asset implementation contract address.
    address latestVersion;

    // Proposed next asset implementation contract address.
    address pendingVersion;

    // Upgrade freeze-time start.
    uint pendingVersionTimestamp;

    // Timespan for users to review the new implementation and make decision.
    uint constant UPGRADE_FREEZE_TIME = 3 days;

    // Asset implementation contract address that user decided to stick with.
    // 0x0 means that user uses latest version.
    mapping(address => address) userOptOutVersion;

    /**
     * Only asset implementation contract assigned to sender is allowed to call.
     */
    modifier onlyImplementationFor(address _sender) {
        if (getVersionFor(_sender) == msg.sender) {
            _;
        }
    }

    /**
     * Returns asset implementation contract address assigned to sender.
     *
     * @param _sender sender address.
     *
     * @return asset implementation contract address.
     */
    function getVersionFor(address _sender) constant returns(address) {
        return userOptOutVersion[_sender] == 0 ? latestVersion : userOptOutVersion[_sender];
    }

    /**
     * Returns current asset implementation contract address.
     *
     * @return asset implementation contract address.
     */
    function getLatestVersion() constant returns(address) {
        return latestVersion;
    }

    /**
     * Returns proposed next asset implementation contract address.
     *
     * @return asset implementation contract address.
     */
    function getPendingVersion() constant returns(address) {
        return pendingVersion;
    }

    /**
     * Returns upgrade freeze-time start.
     *
     * @return freeze-time start.
     */
    function getPendingVersionTimestamp() constant returns(uint) {
        return pendingVersionTimestamp;
    }

    /**
     * Propose next asset implementation contract address.
     *
     * Can only be called by current asset owner.
     *
     * Note: freeze-time should not be applied for the initial setup.
     *
     * @param _newVersion asset implementation contract address.
     *
     * @return success.
     */
    function proposeUpgrade(address _newVersion) onlyAssetOwner() returns(bool) {
        // Should not already be in the upgrading process.
        if (pendingVersion != 0x0) {
            return false;
        }
        // New version address should be other than 0x0.
        if (_newVersion == 0x0) {
            return false;
        }
        // Don't apply freeze-time for the initial setup.
        if (latestVersion == 0x0) {
            latestVersion = _newVersion;
            return true;
        }
        pendingVersion = _newVersion;
        pendingVersionTimestamp = now;
        UpgradeProposal(_newVersion);
        return true;
    }

    /**
     * Cancel the pending upgrade process.
     *
     * Can only be called by current asset owner.
     *
     * @return success.
     */
    function purgeUpgrade() onlyAssetOwner() returns(bool) {
        if (pendingVersion == 0x0) {
            return false;
        }
        delete pendingVersion;
        delete pendingVersionTimestamp;
        return true;
    }

    /**
     * Finalize an upgrade process setting new asset implementation contract address.
     *
     * Can only be called after an upgrade freeze-time.
     *
     * @return success.
     */
    function commitUpgrade() returns(bool) {
        if (pendingVersion == 0x0) {
            return false;
        }
        if (pendingVersionTimestamp + UPGRADE_FREEZE_TIME > now) {
            return false;
        }
        latestVersion = pendingVersion;
        delete pendingVersion;
        delete pendingVersionTimestamp;
        return true;
    }

    /**
     * Disagree with proposed upgrade, and stick with current asset implementation
     * until further explicit agreement to upgrade.
     *
     * @return success.
     */
    function optOut() returns(bool) {
        if (userOptOutVersion[msg.sender] != 0x0) {
            return false;
        }
        userOptOutVersion[msg.sender] = latestVersion;
        return true;
    }

    /**
     * Implicitly agree to upgrade to current and future asset implementation upgrades,
     * until further explicit disagreement.
     *
     * @return success.
     */
    function optIn() returns(bool) {
        delete userOptOutVersion[msg.sender];
        return true;
    }

    // Backwards compatibility.
    function multiAsset() constant returns(EToken2Interface) {
        return etoken2;
    }
}

contract UniBrightToken is AssetProxy {
    function change(string _symbol, string _name) onlyAssetOwner() returns(bool) {
        if (etoken2.isLocked(etoken2Symbol)) {
            return false;
        }
        name = _name;
        symbol = _symbol;
        return true;
    }
}

// This software is a subject to Ambisafe License Agreement.
// No use or distribution is allowed without written permission from Ambisafe.
// https://ambisafe.com/terms.pdf

pragma solidity 0.4.8;

contract Ambi2 {
    function claimFor(address _address, address _owner) returns(bool);
    function hasRole(address _from, bytes32 _role, address _to) constant returns(bool);
    function isOwner(address _node, address _owner) constant returns(bool);
}

contract Ambi2Enabled {
    Ambi2 ambi2;

    modifier onlyRole(bytes32 _role) {
        if (address(ambi2) != 0x0 && ambi2.hasRole(this, _role, msg.sender)) {
            _;
        }
    }

    // Perform only after claiming the node, or claim in the same tx.
    function setupAmbi2(Ambi2 _ambi2) returns(bool) {
        if (address(ambi2) != 0x0) {
            return false;
        }

        ambi2 = _ambi2;
        return true;
    }
}

contract Ambi2EnabledFull is Ambi2Enabled {
    // Setup and claim atomically.
    function setupAmbi2(Ambi2 _ambi2) returns(bool) {
        if (address(ambi2) != 0x0) {
            return false;
        }
        if (!_ambi2.claimFor(this, msg.sender) && !_ambi2.isOwner(this, msg.sender)) {
            return false;
        }

        ambi2 = _ambi2;
        return true;
    }
}

contract RegistryICAPInterface {
    function parse(bytes32 _icap) constant returns(address, bytes32, bool);
    function institutions(bytes32 _institution) constant returns(address);
}

contract Cosigner {
    function consumeOperation(bytes32 _opHash, uint _required) returns(bool);
}

contract Emitter {
    function emitTransfer(address _from, address _to, bytes32 _symbol, uint _value, string _reference);
    function emitTransferToICAP(address _from, address _to, bytes32 _icap, uint _value, string _reference);
    function emitIssue(bytes32 _symbol, uint _value, address _by);
    function emitRevoke(bytes32 _symbol, uint _value, address _by);
    function emitOwnershipChange(address _from, address _to, bytes32 _symbol);
    function emitApprove(address _from, address _spender, bytes32 _symbol, uint _value);
    function emitRecovery(address _from, address _to, address _by);
    function emitError(bytes32 _message);
    function emitChange(bytes32 _symbol);
}

contract Proxy {
    function emitTransfer(address _from, address _to, uint _value);
    function emitApprove(address _from, address _spender, uint _value);
}

/**
 * @title EToken2.
 *
 * The official Ambisafe assets platform powering all kinds of tokens.
 * EToken2 uses EventsHistory contract to keep events, so that in case it needs to be redeployed
 * at some point, all the events keep appearing at the same place.
 *
 * Every asset is meant to be used through a proxy contract. Only one proxy contract have access
 * rights for a particular asset.
 *
 * Features: assets issuance, transfers, allowances, supply adjustments, lost wallet access recovery.
 *           cosignature check, ICAP.
 *
 * Note: all the non constant functions return false instead of throwing in case if state change
 * didn't happen yet.
 */
contract EToken2 is Ambi2EnabledFull {
    mapping(bytes32 => bool) switches;

    function isEnabled(bytes32 _switch) constant returns(bool) {
        return switches[_switch];
    }

    function enableSwitch(bytes32 _switch) onlyRole('issuance') returns(bool) {
        switches[_switch] = true;
        return true;
    }

    modifier checkEnabledSwitch(bytes32 _switch) {
        if (!isEnabled(_switch)) {
            _error('Feature is disabled');
        } else {
            _;
        }
    }

    enum Features { Issue, TransferWithReference, Revoke, ChangeOwnership, Allowances, ICAP }

    // Structure of a particular asset.
    struct Asset {
        uint owner;                       // Asset's owner id.
        uint totalSupply;                 // Asset's total supply.
        string name;                      // Asset's name, for information purposes.
        string description;               // Asset's description, for information purposes.
        bool isReissuable;                // Indicates if asset have dynamic of fixed supply.
        uint8 baseUnit;                   // Proposed number of decimals.
        bool isLocked;                    // Are changes still allowed.
        mapping(uint => Wallet) wallets;  // Holders wallets.
    }

    // Structure of an asset holder wallet for particular asset.
    struct Wallet {
        uint balance;
        mapping(uint => uint) allowance;
    }

    // Structure of an asset holder.
    struct Holder {
        address addr;                    // Current address of the holder.
        Cosigner cosigner;               // Cosigner contract for 2FA and recovery.
        mapping(address => bool) trust;  // Addresses that are trusted with recovery proocedure.
    }

    // Iterable mapping pattern is used for holders.
    uint public holdersCount;
    mapping(uint => Holder) public holders;

    // This is an access address mapping. Many addresses may have access to a single holder.
    mapping(address => uint) holderIndex;

    // Asset symbol to asset mapping.
    mapping(bytes32 => Asset) public assets;

    // Asset symbol to asset proxy mapping.
    mapping(bytes32 => address) public proxies;

    // ICAP registry contract.
    RegistryICAPInterface public registryICAP;

    // Should use interface of the emitter, but address of events history.
    Emitter public eventsHistory;

    /**
     * Emits Error event with specified error message.
     *
     * Should only be used if no state changes happened.
     *
     * @param _message error message.
     */
    function _error(bytes32 _message) internal {
        eventsHistory.emitError(_message);
    }

    /**
     * Sets EventsHstory contract address.
     *
     * Can be set only once, and only by contract owner.
     *
     * @param _eventsHistory EventsHistory contract address.
     *
     * @return success.
     */
    function setupEventsHistory(Emitter _eventsHistory) onlyRole('setup') returns(bool) {
        if (address(eventsHistory) != 0) {
            return false;
        }
        eventsHistory = _eventsHistory;
        return true;
    }

    /**
     * Sets RegistryICAP contract address.
     *
     * Can be set only once, and only by contract owner.
     *
     * @param _registryICAP RegistryICAP contract address.
     *
     * @return success.
     */
    function setupRegistryICAP(RegistryICAPInterface _registryICAP) onlyRole('setup') returns(bool) {
        if (address(registryICAP) != 0) {
            return false;
        }
        registryICAP = _registryICAP;
        return true;
    }

    /**
     * Emits Error if called not by asset owner.
     */
    modifier onlyOwner(bytes32 _symbol) {
        if (_isSignedOwner(_symbol)) {
            _;
        } else {
            _error('Only owner: access denied');
        }
    }

    /**
     * Emits Error if called not by asset proxy.
     */
    modifier onlyProxy(bytes32 _symbol) {
        if (_isProxy(_symbol)) {
            _;
        } else {
            _error('Only proxy: access denied');
        }
    }

    /**
     * Emits Error if _from doesn't trust _to.
     */
    modifier checkTrust(address _from, address _to) {
        if (isTrusted(_from, _to)) {
            _;
        } else {
            _error('Only trusted: access denied');
        }
    }

    function _isSignedOwner(bytes32 _symbol) internal checkSigned(getHolderId(msg.sender), 1) returns(bool) {
        return isOwner(msg.sender, _symbol);
    }

    /**
     * Check asset existance.
     *
     * @param _symbol asset symbol.
     *
     * @return asset existance.
     */
    function isCreated(bytes32 _symbol) constant returns(bool) {
        return assets[_symbol].owner != 0;
    }

    function isLocked(bytes32 _symbol) constant returns(bool) {
        return assets[_symbol].isLocked;
    }

    /**
     * Returns asset decimals.
     *
     * @param _symbol asset symbol.
     *
     * @return asset decimals.
     */
    function baseUnit(bytes32 _symbol) constant returns(uint8) {
        return assets[_symbol].baseUnit;
    }

    /**
     * Returns asset name.
     *
     * @param _symbol asset symbol.
     *
     * @return asset name.
     */
    function name(bytes32 _symbol) constant returns(string) {
        return assets[_symbol].name;
    }

    /**
     * Returns asset description.
     *
     * @param _symbol asset symbol.
     *
     * @return asset description.
     */
    function description(bytes32 _symbol) constant returns(string) {
        return assets[_symbol].description;
    }

    /**
     * Returns asset reissuability.
     *
     * @param _symbol asset symbol.
     *
     * @return asset reissuability.
     */
    function isReissuable(bytes32 _symbol) constant returns(bool) {
        return assets[_symbol].isReissuable;
    }

    /**
     * Returns asset owner address.
     *
     * @param _symbol asset symbol.
     *
     * @return asset owner address.
     */
    function owner(bytes32 _symbol) constant returns(address) {
        return holders[assets[_symbol].owner].addr;
    }

    /**
     * Check if specified address has asset owner rights.
     *
     * @param _owner address to check.
     * @param _symbol asset symbol.
     *
     * @return owner rights availability.
     */
    function isOwner(address _owner, bytes32 _symbol) constant returns(bool) {
        return isCreated(_symbol) && (assets[_symbol].owner == getHolderId(_owner));
    }

    /**
     * Returns asset total supply.
     *
     * @param _symbol asset symbol.
     *
     * @return asset total supply.
     */
    function totalSupply(bytes32 _symbol) constant returns(uint) {
        return assets[_symbol].totalSupply;
    }

    /**
     * Returns asset balance for current address of a particular holder.
     *
     * @param _holder holder address.
     * @param _symbol asset symbol.
     *
     * @return holder balance.
     */
    function balanceOf(address _holder, bytes32 _symbol) constant returns(uint) {
        uint holderId = getHolderId(_holder);
        return holders[holderId].addr == _holder ? _balanceOf(holderId, _symbol) : 0;
    }

    /**
     * Returns asset balance for a particular holder id.
     *
     * @param _holderId holder id.
     * @param _symbol asset symbol.
     *
     * @return holder balance.
     */
    function _balanceOf(uint _holderId, bytes32 _symbol) constant internal returns(uint) {
        return assets[_symbol].wallets[_holderId].balance;
    }

    /**
     * Returns current address for a particular holder id.
     *
     * @param _holderId holder id.
     *
     * @return holder address.
     */
    function _address(uint _holderId) constant internal returns(address) {
        return holders[_holderId].addr;
    }

    function _isProxy(bytes32 _symbol) constant internal returns(bool) {
        return proxies[_symbol] == msg.sender;
    }

    /**
     * Sets Proxy contract address for a particular asset.
     *
     * Can be set only once for each asset, and only by contract owner.
     *
     * @param _address Proxy contract address.
     * @param _symbol asset symbol.
     *
     * @return success.
     */
    function setProxy(address _address, bytes32 _symbol) onlyOwner(_symbol) returns(bool) {
        if (proxies[_symbol] != 0x0 && assets[_symbol].isLocked) {
            return false;
        }
        proxies[_symbol] = _address;
        return true;
    }

    /**
     * Transfers asset balance between holders wallets.
     *
     * @param _fromId holder id to take from.
     * @param _toId holder id to give to.
     * @param _value amount to transfer.
     * @param _symbol asset symbol.
     */
    function _transferDirect(uint _fromId, uint _toId, uint _value, bytes32 _symbol) internal {
        assets[_symbol].wallets[_fromId].balance -= _value;
        assets[_symbol].wallets[_toId].balance += _value;
    }

    /**
     * Transfers asset balance between holders wallets.
     *
     * Performs sanity checks and takes care of allowances adjustment.
     *
     * @param _fromId holder id to take from.
     * @param _toId holder id to give to.
     * @param _value amount to transfer.
     * @param _symbol asset symbol.
     * @param _reference transfer comment to be included in a Transfer event.
     * @param _senderId transfer initiator holder id.
     *
     * @return success.
     */
    function _transfer(uint _fromId, uint _toId, uint _value, bytes32 _symbol, string _reference, uint _senderId) internal checkSigned(_senderId, 1) returns(bool) {
        // Should not allow to send to oneself.
        if (_fromId == _toId) {
            _error('Cannot send to oneself');
            return false;
        }
        // Should have positive value.
        if (_value == 0) {
            _error('Cannot send 0 value');
            return false;
        }
        // Should have enough balance.
        if (_balanceOf(_fromId, _symbol) < _value) {
            _error('Insufficient balance');
            return false;
        }
        // Should allow references.
        if (bytes(_reference).length > 0 && !isEnabled(sha3(_symbol, Features.TransferWithReference))) {
            _error('References feature is disabled');
            return false;
        }
        // Should have enough allowance.
        if (_fromId != _senderId && _allowance(_fromId, _senderId, _symbol) < _value) {
            _error('Not enough allowance');
            return false;
        }
        // Adjust allowance.
        if (_fromId != _senderId) {
            assets[_symbol].wallets[_fromId].allowance[_senderId] -= _value;
        }
        _transferDirect(_fromId, _toId, _value, _symbol);
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitTransfer(_address(_fromId), _address(_toId), _symbol, _value, _reference);
        _proxyTransferEvent(_fromId, _toId, _value, _symbol);
        return true;
    }

    // Feature and proxy checks done internally due to unknown symbol when the function is called.
    function _transferToICAP(uint _fromId, bytes32 _icap, uint _value, string _reference, uint _senderId) internal returns(bool) {
        var (to, symbol, success) = registryICAP.parse(_icap);
        if (!success) {
            _error('ICAP is not registered');
            return false;
        }
        if (!isEnabled(sha3(symbol, Features.ICAP))) {
            _error('ICAP feature is disabled');
            return false;
        }
        if (!_isProxy(symbol)) {
            _error('Only proxy: access denied');
            return false;
        }
        uint toId = _createHolderId(to);
        if (!_transfer(_fromId, toId, _value, symbol, _reference, _senderId)) {
            return false;
        }
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitTransferToICAP(_address(_fromId), _address(toId), _icap, _value, _reference);
        return true;
    }

    function proxyTransferFromToICAPWithReference(address _from, bytes32 _icap, uint _value, string _reference, address _sender) returns(bool) {
        return _transferToICAP(getHolderId(_from), _icap, _value, _reference, getHolderId(_sender));
    }

    /**
     * Ask asset Proxy contract to emit ERC20 compliant Transfer event.
     *
     * @param _fromId holder id to take from.
     * @param _toId holder id to give to.
     * @param _value amount to transfer.
     * @param _symbol asset symbol.
     */
    function _proxyTransferEvent(uint _fromId, uint _toId, uint _value, bytes32 _symbol) internal {
        if (proxies[_symbol] != 0x0) {
            // Internal Out Of Gas/Throw: revert this transaction too;
            // Recursive Call: safe, all changes already made.
            Proxy(proxies[_symbol]).emitTransfer(_address(_fromId), _address(_toId), _value);
        }
    }

    /**
     * Returns holder id for the specified address.
     *
     * @param _holder holder address.
     *
     * @return holder id.
     */
    function getHolderId(address _holder) constant returns(uint) {
        return holderIndex[_holder];
    }

    /**
     * Returns holder id for the specified address, creates it if needed.
     *
     * @param _holder holder address.
     *
     * @return holder id.
     */
    function _createHolderId(address _holder) internal returns(uint) {
        uint holderId = holderIndex[_holder];
        if (holderId == 0) {
            holderId = ++holdersCount;
            holders[holderId].addr = _holder;
            holderIndex[_holder] = holderId;
        }
        return holderId;
    }

    /**
     * Issues new asset token on the platform.
     *
     * Tokens issued with this call go straight to contract owner.
     * Each symbol can be issued only once, and only by contract owner.
     *
     * _isReissuable is included in checkEnabledSwitch because it should be
     * explicitly allowed before issuing new asset.
     *
     * @param _symbol asset symbol.
     * @param _value amount of tokens to issue immediately.
     * @param _name name of the asset.
     * @param _description description for the asset.
     * @param _baseUnit number of decimals.
     * @param _isReissuable dynamic or fixed supply.
     *
     * @return success.
     */
    function issueAsset(bytes32 _symbol, uint _value, string _name, string _description, uint8 _baseUnit, bool _isReissuable) checkEnabledSwitch(sha3(_symbol, _isReissuable, Features.Issue)) returns(bool) {
        // Should have positive value if supply is going to be fixed.
        if (_value == 0 && !_isReissuable) {
            _error('Cannot issue 0 value fixed asset');
            return false;
        }
        // Should not be issued yet.
        if (isCreated(_symbol)) {
            _error('Asset already issued');
            return false;
        }
        uint holderId = _createHolderId(msg.sender);

        assets[_symbol] = Asset(holderId, _value, _name, _description, _isReissuable, _baseUnit, false);
        assets[_symbol].wallets[holderId].balance = _value;
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitIssue(_symbol, _value, _address(holderId));
        return true;
    }

    function changeAsset(bytes32 _symbol, string _name, string _description, uint8 _baseUnit) onlyOwner(_symbol) returns(bool) {
        if (isLocked(_symbol)) {
            _error('Asset is locked');
            return false;
        }
        assets[_symbol].name = _name;
        assets[_symbol].description = _description;
        assets[_symbol].baseUnit = _baseUnit;
        eventsHistory.emitChange(_symbol);
        return true;
    }

    function lockAsset(bytes32 _symbol) onlyOwner(_symbol) returns(bool) {
        if (isLocked(_symbol)) {
            _error('Asset is locked');
            return false;
        }
        assets[_symbol].isLocked = true;
        return true;
    }

    /**
     * Issues additional asset tokens if the asset have dynamic supply.
     *
     * Tokens issued with this call go straight to asset owner.
     * Can only be called by asset owner.
     *
     * @param _symbol asset symbol.
     * @param _value amount of additional tokens to issue.
     *
     * @return success.
     */
    function reissueAsset(bytes32 _symbol, uint _value) onlyOwner(_symbol) returns(bool) {
        // Should have positive value.
        if (_value == 0) {
            _error('Cannot reissue 0 value');
            return false;
        }
        Asset asset = assets[_symbol];
        // Should have dynamic supply.
        if (!asset.isReissuable) {
            _error('Cannot reissue fixed asset');
            return false;
        }
        // Resulting total supply should not overflow.
        if (asset.totalSupply + _value < asset.totalSupply) {
            _error('Total supply overflow');
            return false;
        }
        uint holderId = getHolderId(msg.sender);
        asset.wallets[holderId].balance += _value;
        asset.totalSupply += _value;
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitIssue(_symbol, _value, _address(holderId));
        _proxyTransferEvent(0, holderId, _value, _symbol);
        return true;
    }

    /**
     * Destroys specified amount of senders asset tokens.
     *
     * @param _symbol asset symbol.
     * @param _value amount of tokens to destroy.
     *
     * @return success.
     */
    function revokeAsset(bytes32 _symbol, uint _value) checkEnabledSwitch(sha3(_symbol, Features.Revoke)) checkSigned(getHolderId(msg.sender), 1) returns(bool) {
        // Should have positive value.
        if (_value == 0) {
            _error('Cannot revoke 0 value');
            return false;
        }
        Asset asset = assets[_symbol];
        uint holderId = getHolderId(msg.sender);
        // Should have enough tokens.
        if (asset.wallets[holderId].balance < _value) {
            _error('Not enough tokens to revoke');
            return false;
        }
        asset.wallets[holderId].balance -= _value;
        asset.totalSupply -= _value;
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitRevoke(_symbol, _value, _address(holderId));
        _proxyTransferEvent(holderId, 0, _value, _symbol);
        return true;
    }

    /**
     * Passes asset ownership to specified address.
     *
     * Only ownership is changed, balances are not touched.
     * Can only be called by asset owner.
     *
     * @param _symbol asset symbol.
     * @param _newOwner address to become a new owner.
     *
     * @return success.
     */
    function changeOwnership(bytes32 _symbol, address _newOwner) checkEnabledSwitch(sha3(_symbol, Features.ChangeOwnership)) onlyOwner(_symbol) returns(bool) {
        Asset asset = assets[_symbol];
        uint newOwnerId = _createHolderId(_newOwner);
        // Should pass ownership to another holder.
        if (asset.owner == newOwnerId) {
            _error('Cannot pass ownership to oneself');
            return false;
        }
        address oldOwner = _address(asset.owner);
        asset.owner = newOwnerId;
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitOwnershipChange(oldOwner, _address(newOwnerId), _symbol);
        return true;
    }

    function setCosignerAddress(Cosigner _cosigner) checkSigned(_createHolderId(msg.sender), 1) returns(bool) {
        if (!_checkSigned(_cosigner, getHolderId(msg.sender), 1)) {
            _error('Invalid cosigner');
            return false;
        }
        holders[_createHolderId(msg.sender)].cosigner = _cosigner;
        return true;
    }

    function isCosignerSet(uint _holderId) constant returns(bool) {
        return address(holders[_holderId].cosigner) != 0x0;
    }

    function _checkSigned(Cosigner _cosigner, uint _holderId, uint _required) internal returns(bool) {
        return _cosigner.consumeOperation(sha3(msg.data, _holderId), _required);
    }

    modifier checkSigned(uint _holderId, uint _required) {
        if (!isCosignerSet(_holderId) || _checkSigned(holders[_holderId].cosigner, _holderId, _required)) {
            _;
        } else {
            _error('Cosigner: access denied');
        }
    }

    /**
     * Check if specified holder trusts an address with recovery procedure.
     *
     * @param _from truster.
     * @param _to trustee.
     *
     * @return trust existance.
     */
    function isTrusted(address _from, address _to) constant returns(bool) {
        return holders[getHolderId(_from)].trust[_to];
    }

    /**
     * Trust an address to perform recovery procedure for the caller.
     *
     * @param _to trustee.
     *
     * @return success.
     */
    function trust(address _to) returns(bool) {
        uint fromId = _createHolderId(msg.sender);
        // Should trust to another address.
        if (fromId == getHolderId(_to)) {
            _error('Cannot trust to oneself');
            return false;
        }
        // Should trust to yet untrusted.
        if (isTrusted(msg.sender, _to)) {
            _error('Already trusted');
            return false;
        }
        holders[fromId].trust[_to] = true;
        return true;
    }

    /**
     * Revoke trust to perform recovery procedure from an address.
     *
     * @param _to trustee.
     *
     * @return success.
     */
    function distrust(address _to) checkTrust(msg.sender, _to) returns(bool) {
        holders[getHolderId(msg.sender)].trust[_to] = false;
        return true;
    }

    /**
     * Perform recovery procedure.
     *
     * This function logic is actually more of an grantAccess(uint _holderId, address _to).
     * It grants another address access to recovery subject wallets.
     * Can only be called by trustee of recovery subject.
     * If cosigning is enabled, should have atleast 2 confirmations.
     *
     * @dev Deprecated. Backward compatibility.
     *
     * @param _from holder address to recover from.
     * @param _to address to grant access to.
     *
     * @return success.
     */
    function recover(address _from, address _to) checkTrust(_from, msg.sender) returns(bool) {
        return _grantAccess(getHolderId(_from), _to);
    }

    /**
     * Perform recovery procedure.
     *
     * This function logic is actually more of an grantAccess(uint _holderId, address _to).
     * It grants another address access to subject holder wallets.
     * Can only be called if pre-confirmed by atleast 2 cosign oracles.
     *
     * @param _from holder address to recover from.
     * @param _to address to grant access to.
     *
     * @return success.
     */
    function grantAccess(address _from, address _to) returns(bool) {
        if (!isCosignerSet(getHolderId(_from))) {
            _error('Cosigner not set');
            return false;
        }
        return _grantAccess(getHolderId(_from), _to);
    }

    function _grantAccess(uint _fromId, address _to) internal checkSigned(_fromId, 2) returns(bool) {
        // Should recover to previously unused address.
        if (getHolderId(_to) != 0) {
            _error('Should recover to new address');
            return false;
        }
        // We take current holder address because it might not equal _from.
        // It is possible to recover from any old holder address, but event should have the current one.
        address from = holders[_fromId].addr;
        holders[_fromId].addr = _to;
        holderIndex[_to] = _fromId;
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitRecovery(from, _to, msg.sender);
        return true;
    }

    /**
     * Sets asset spending allowance for a specified spender.
     *
     * Note: to revoke allowance, one needs to set allowance to 0.
     *
     * @param _spenderId holder id to set allowance for.
     * @param _value amount to allow.
     * @param _symbol asset symbol.
     * @param _senderId approve initiator holder id.
     *
     * @return success.
     */
    function _approve(uint _spenderId, uint _value, bytes32 _symbol, uint _senderId) internal checkEnabledSwitch(sha3(_symbol, Features.Allowances)) checkSigned(_senderId, 1) returns(bool) {
        // Asset should exist.
        if (!isCreated(_symbol)) {
            _error('Asset is not issued');
            return false;
        }
        // Should allow to another holder.
        if (_senderId == _spenderId) {
            _error('Cannot approve to oneself');
            return false;
        }
        assets[_symbol].wallets[_senderId].allowance[_spenderId] = _value;
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitApprove(_address(_senderId), _address(_spenderId), _symbol, _value);
        if (proxies[_symbol] != 0x0) {
            // Internal Out Of Gas/Throw: revert this transaction too;
            // Recursive Call: safe, all changes already made.
            Proxy(proxies[_symbol]).emitApprove(_address(_senderId), _address(_spenderId), _value);
        }
        return true;
    }

    /**
     * Sets asset spending allowance for a specified spender.
     *
     * Can only be called by asset proxy.
     *
     * @param _spender holder address to set allowance to.
     * @param _value amount to allow.
     * @param _symbol asset symbol.
     * @param _sender approve initiator address.
     *
     * @return success.
     */
    function proxyApprove(address _spender, uint _value, bytes32 _symbol, address _sender) onlyProxy(_symbol) returns(bool) {
        return _approve(_createHolderId(_spender), _value, _symbol, _createHolderId(_sender));
    }

    /**
     * Returns asset allowance from one holder to another.
     *
     * @param _from holder that allowed spending.
     * @param _spender holder that is allowed to spend.
     * @param _symbol asset symbol.
     *
     * @return holder to spender allowance.
     */
    function allowance(address _from, address _spender, bytes32 _symbol) constant returns(uint) {
        return _allowance(getHolderId(_from), getHolderId(_spender), _symbol);
    }

    /**
     * Returns asset allowance from one holder to another.
     *
     * @param _fromId holder id that allowed spending.
     * @param _toId holder id that is allowed to spend.
     * @param _symbol asset symbol.
     *
     * @return holder to spender allowance.
     */
    function _allowance(uint _fromId, uint _toId, bytes32 _symbol) constant internal returns(uint) {
        return assets[_symbol].wallets[_fromId].allowance[_toId];
    }

    /**
     * Prforms allowance transfer of asset balance between holders wallets.
     *
     * Can only be called by asset proxy.
     *
     * @param _from holder address to take from.
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     * @param _symbol asset symbol.
     * @param _reference transfer comment to be included in a Transfer event.
     * @param _sender allowance transfer initiator address.
     *
     * @return success.
     */
    function proxyTransferFromWithReference(address _from, address _to, uint _value, bytes32 _symbol, string _reference, address _sender) onlyProxy(_symbol) returns(bool) {
        return _transfer(getHolderId(_from), _createHolderId(_to), _value, _symbol, _reference, getHolderId(_sender));
    }
}

// File: contracts/interfaces/IUniswapV2Pair.sol

pragma solidity >=0.5.0;

interface IUniswapV2Pair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

// File: contracts/interfaces/IUniswapV2ERC20.sol

pragma solidity >=0.5.0;

interface IUniswapV2ERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
}

// File: contracts/libraries/SafeMath.sol

pragma solidity =0.5.16;

// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)

library SafeMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x, 'ds-math-add-overflow');
    }

    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, 'ds-math-sub-underflow');
    }

    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
    }
}

// File: contracts/UniswapV2ERC20.sol

pragma solidity =0.5.16;



contract UniswapV2ERC20 is IUniswapV2ERC20 {
    using SafeMath for uint;

    string public constant name = 'Uniswap V2';
    string public constant symbol = 'UNI-V2';
    uint8 public constant decimals = 18;
    uint  public totalSupply;
    mapping(address => uint) public balanceOf;
    mapping(address => mapping(address => uint)) public allowance;

    bytes32 public DOMAIN_SEPARATOR;
    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
    mapping(address => uint) public nonces;

    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    constructor() public {
        uint chainId;
        assembly {
            chainId := chainid
        }
        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
                keccak256(bytes(name)),
                keccak256(bytes('1')),
                chainId,
                address(this)
            )
        );
    }

    function _mint(address to, uint value) internal {
        totalSupply = totalSupply.add(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(address(0), to, value);
    }

    function _burn(address from, uint value) internal {
        balanceOf[from] = balanceOf[from].sub(value);
        totalSupply = totalSupply.sub(value);
        emit Transfer(from, address(0), value);
    }

    function _approve(address owner, address spender, uint value) private {
        allowance[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    function _transfer(address from, address to, uint value) private {
        balanceOf[from] = balanceOf[from].sub(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(from, to, value);
    }

    function approve(address spender, uint value) external returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    function transfer(address to, uint value) external returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    function transferFrom(address from, address to, uint value) external returns (bool) {
        if (allowance[from][msg.sender] != uint(-1)) {
            allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
        }
        _transfer(from, to, value);
        return true;
    }

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external {
        require(deadline >= block.timestamp, 'UniswapV2: EXPIRED');
        bytes32 digest = keccak256(
            abi.encodePacked(
                '\x19\x01',
                DOMAIN_SEPARATOR,
                keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
            )
        );
        address recoveredAddress = ecrecover(digest, v, r, s);
        require(recoveredAddress != address(0) && recoveredAddress == owner, 'UniswapV2: INVALID_SIGNATURE');
        _approve(owner, spender, value);
    }
}

// File: contracts/libraries/Math.sol

pragma solidity =0.5.16;

// a library for performing various math operations

library Math {
    function min(uint x, uint y) internal pure returns (uint z) {
        z = x < y ? x : y;
    }

    // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
    function sqrt(uint y) internal pure returns (uint z) {
        if (y > 3) {
            z = y;
            uint x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }
}

// File: contracts/libraries/UQ112x112.sol

pragma solidity =0.5.16;

// a library for handling binary fixed point numbers (https://en.wikipedia.org/wiki/Q_(number_format))

// range: [0, 2**112 - 1]
// resolution: 1 / 2**112

library UQ112x112 {
    uint224 constant Q112 = 2**112;

    // encode a uint112 as a UQ112x112
    function encode(uint112 y) internal pure returns (uint224 z) {
        z = uint224(y) * Q112; // never overflows
    }

    // divide a UQ112x112 by a uint112, returning a UQ112x112
    function uqdiv(uint224 x, uint112 y) internal pure returns (uint224 z) {
        z = x / uint224(y);
    }
}

// File: contracts/interfaces/IERC20.sol

pragma solidity >=0.5.0;

interface IERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
}

// File: contracts/interfaces/IUniswapV2Factory.sol

pragma solidity >=0.5.0;

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

// File: contracts/interfaces/IUniswapV2Callee.sol

pragma solidity >=0.5.0;

interface IUniswapV2Callee {
    function uniswapV2Call(address sender, uint amount0, uint amount1, bytes calldata data) external;
}

// File: contracts/UniswapV2Pair.sol

pragma solidity =0.5.16;








contract UniswapV2Pair is IUniswapV2Pair, UniswapV2ERC20 {
    using SafeMath  for uint;
    using UQ112x112 for uint224;

    uint public constant MINIMUM_LIQUIDITY = 10**3;
    bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));

    address public factory;
    address public token0;
    address public token1;

    uint112 private reserve0;           // uses single storage slot, accessible via getReserves
    uint112 private reserve1;           // uses single storage slot, accessible via getReserves
    uint32  private blockTimestampLast; // uses single storage slot, accessible via getReserves

    uint public price0CumulativeLast;
    uint public price1CumulativeLast;
    uint public kLast; // reserve0 * reserve1, as of immediately after the most recent liquidity event

    uint private unlocked = 1;
    modifier lock() {
        require(unlocked == 1, 'UniswapV2: LOCKED');
        unlocked = 0;
        _;
        unlocked = 1;
    }

    function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {
        _reserve0 = reserve0;
        _reserve1 = reserve1;
        _blockTimestampLast = blockTimestampLast;
    }

    function _safeTransfer(address token, address to, uint value) private {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'UniswapV2: TRANSFER_FAILED');
    }

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    constructor() public {
        factory = msg.sender;
    }

    // called once by the factory at time of deployment
    function initialize(address _token0, address _token1) external {
        require(msg.sender == factory, 'UniswapV2: FORBIDDEN'); // sufficient check
        token0 = _token0;
        token1 = _token1;
    }

    // update reserves and, on the first call per block, price accumulators
    function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {
        require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'UniswapV2: OVERFLOW');
        uint32 blockTimestamp = uint32(block.timestamp % 2**32);
        uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
        if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
            // * never overflows, and + overflow is desired
            price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;
            price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;
        }
        reserve0 = uint112(balance0);
        reserve1 = uint112(balance1);
        blockTimestampLast = blockTimestamp;
        emit Sync(reserve0, reserve1);
    }

    // if fee is on, mint liquidity equivalent to 1/6th of the growth in sqrt(k)
    function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
        address feeTo = IUniswapV2Factory(factory).feeTo();
        feeOn = feeTo != address(0);
        uint _kLast = kLast; // gas savings
        if (feeOn) {
            if (_kLast != 0) {
                uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));
                uint rootKLast = Math.sqrt(_kLast);
                if (rootK > rootKLast) {
                    uint numerator = totalSupply.mul(rootK.sub(rootKLast));
                    uint denominator = rootK.mul(5).add(rootKLast);
                    uint liquidity = numerator / denominator;
                    if (liquidity > 0) _mint(feeTo, liquidity);
                }
            }
        } else if (_kLast != 0) {
            kLast = 0;
        }
    }

    // this low-level function should be called from a contract which performs important safety checks
    function mint(address to) external lock returns (uint liquidity) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        uint balance0 = IERC20(token0).balanceOf(address(this));
        uint balance1 = IERC20(token1).balanceOf(address(this));
        uint amount0 = balance0.sub(_reserve0);
        uint amount1 = balance1.sub(_reserve1);

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        if (_totalSupply == 0) {
            liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
           _mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
        } else {
            liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
        }
        require(liquidity > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_MINTED');
        _mint(to, liquidity);

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Mint(msg.sender, amount0, amount1);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function burn(address to) external lock returns (uint amount0, uint amount1) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        address _token0 = token0;                                // gas savings
        address _token1 = token1;                                // gas savings
        uint balance0 = IERC20(_token0).balanceOf(address(this));
        uint balance1 = IERC20(_token1).balanceOf(address(this));
        uint liquidity = balanceOf[address(this)];

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution
        amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution
        require(amount0 > 0 && amount1 > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_BURNED');
        _burn(address(this), liquidity);
        _safeTransfer(_token0, to, amount0);
        _safeTransfer(_token1, to, amount1);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Burn(msg.sender, amount0, amount1, to);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {
        require(amount0Out > 0 || amount1Out > 0, 'UniswapV2: INSUFFICIENT_OUTPUT_AMOUNT');
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        require(amount0Out < _reserve0 && amount1Out < _reserve1, 'UniswapV2: INSUFFICIENT_LIQUIDITY');

        uint balance0;
        uint balance1;
        { // scope for _token{0,1}, avoids stack too deep errors
        address _token0 = token0;
        address _token1 = token1;
        require(to != _token0 && to != _token1, 'UniswapV2: INVALID_TO');
        if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens
        if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens
        if (data.length > 0) IUniswapV2Callee(to).uniswapV2Call(msg.sender, amount0Out, amount1Out, data);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));
        }
        uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;
        uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;
        require(amount0In > 0 || amount1In > 0, 'UniswapV2: INSUFFICIENT_INPUT_AMOUNT');
        { // scope for reserve{0,1}Adjusted, avoids stack too deep errors
        uint balance0Adjusted = balance0.mul(1000).sub(amount0In.mul(3));
        uint balance1Adjusted = balance1.mul(1000).sub(amount1In.mul(3));
        require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(1000**2), 'UniswapV2: K');
        }

        _update(balance0, balance1, _reserve0, _reserve1);
        emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
    }

    // force balances to match reserves
    function skim(address to) external lock {
        address _token0 = token0; // gas savings
        address _token1 = token1; // gas savings
        _safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));
        _safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));
    }

    // force reserves to match balances
    function sync() external lock {
        _update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);
    }
}