Contract Source Code:

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.23;

/* solhint-disable reason-string */

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/introspection/IERC165.sol";
import "../interfaces/IPaymaster.sol";
import "../interfaces/IEntryPoint.sol";
import "./UserOperationLib.sol";
/**
 * Helper class for creating a paymaster.
 * provides helper methods for staking.
 * Validates that the postOp is called only by the entryPoint.
 */
abstract contract BasePaymaster is IPaymaster, Ownable {
    IEntryPoint public immutable entryPoint;

    uint256 internal constant PAYMASTER_VALIDATION_GAS_OFFSET = UserOperationLib.PAYMASTER_VALIDATION_GAS_OFFSET;
    uint256 internal constant PAYMASTER_POSTOP_GAS_OFFSET = UserOperationLib.PAYMASTER_POSTOP_GAS_OFFSET;
    uint256 internal constant PAYMASTER_DATA_OFFSET = UserOperationLib.PAYMASTER_DATA_OFFSET;

    constructor(IEntryPoint _entryPoint) Ownable(msg.sender) {
        _validateEntryPointInterface(_entryPoint);
        entryPoint = _entryPoint;
    }

    //sanity check: make sure this EntryPoint was compiled against the same
    // IEntryPoint of this paymaster
    function _validateEntryPointInterface(IEntryPoint _entryPoint) internal virtual {
        require(IERC165(address(_entryPoint)).supportsInterface(type(IEntryPoint).interfaceId), "IEntryPoint interface mismatch");
    }

    /// @inheritdoc IPaymaster
    function validatePaymasterUserOp(
        PackedUserOperation calldata userOp,
        bytes32 userOpHash,
        uint256 maxCost
    ) external override returns (bytes memory context, uint256 validationData) {
        _requireFromEntryPoint();
        return _validatePaymasterUserOp(userOp, userOpHash, maxCost);
    }

    /**
     * Validate a user operation.
     * @param userOp     - The user operation.
     * @param userOpHash - The hash of the user operation.
     * @param maxCost    - The maximum cost of the user operation.
     */
    function _validatePaymasterUserOp(
        PackedUserOperation calldata userOp,
        bytes32 userOpHash,
        uint256 maxCost
    ) internal virtual returns (bytes memory context, uint256 validationData);

    /// @inheritdoc IPaymaster
    function postOp(
        PostOpMode mode,
        bytes calldata context,
        uint256 actualGasCost,
        uint256 actualUserOpFeePerGas
    ) external override {
        _requireFromEntryPoint();
        _postOp(mode, context, actualGasCost, actualUserOpFeePerGas);
    }

    /**
     * Post-operation handler.
     * (verified to be called only through the entryPoint)
     * @dev If subclass returns a non-empty context from validatePaymasterUserOp,
     *      it must also implement this method.
     * @param mode          - Enum with the following options:
     *                        opSucceeded - User operation succeeded.
     *                        opReverted  - User op reverted. The paymaster still has to pay for gas.
     *                        postOpReverted - never passed in a call to postOp().
     * @param context       - The context value returned by validatePaymasterUserOp
     * @param actualGasCost - Actual gas used so far (without this postOp call).
     * @param actualUserOpFeePerGas - the gas price this UserOp pays. This value is based on the UserOp's maxFeePerGas
     *                        and maxPriorityFee (and basefee)
     *                        It is not the same as tx.gasprice, which is what the bundler pays.
     */
    function _postOp(
        PostOpMode mode,
        bytes calldata context,
        uint256 actualGasCost,
        uint256 actualUserOpFeePerGas
    ) internal virtual {
        (mode, context, actualGasCost, actualUserOpFeePerGas); // unused params
        // subclass must override this method if validatePaymasterUserOp returns a context
        revert("must override");
    }

    /**
     * Add a deposit for this paymaster, used for paying for transaction fees.
     */
    function deposit() public payable {
        entryPoint.depositTo{value: msg.value}(address(this));
    }

    /**
     * Withdraw value from the deposit.
     * @param withdrawAddress - Target to send to.
     * @param amount          - Amount to withdraw.
     */
    function withdrawTo(
        address payable withdrawAddress,
        uint256 amount
    ) public onlyOwner {
        entryPoint.withdrawTo(withdrawAddress, amount);
    }

    /**
     * Add stake for this paymaster.
     * This method can also carry eth value to add to the current stake.
     * @param unstakeDelaySec - The unstake delay for this paymaster. Can only be increased.
     */
    function addStake(uint32 unstakeDelaySec) external payable onlyOwner {
        entryPoint.addStake{value: msg.value}(unstakeDelaySec);
    }

    /**
     * Return current paymaster's deposit on the entryPoint.
     */
    function getDeposit() public view returns (uint256) {
        return entryPoint.balanceOf(address(this));
    }

    /**
     * Unlock the stake, in order to withdraw it.
     * The paymaster can't serve requests once unlocked, until it calls addStake again
     */
    function unlockStake() external onlyOwner {
        entryPoint.unlockStake();
    }

    /**
     * Withdraw the entire paymaster's stake.
     * stake must be unlocked first (and then wait for the unstakeDelay to be over)
     * @param withdrawAddress - The address to send withdrawn value.
     */
    function withdrawStake(address payable withdrawAddress) external onlyOwner {
        entryPoint.withdrawStake(withdrawAddress);
    }

    /**
     * Validate the call is made from a valid entrypoint
     */
    function _requireFromEntryPoint() internal virtual {
        require(msg.sender == address(entryPoint), "Sender not EntryPoint");
    }
}

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.23;

/* solhint-disable no-inline-assembly */


 /*
  * For simulation purposes, validateUserOp (and validatePaymasterUserOp)
  * must return this value in case of signature failure, instead of revert.
  */
uint256 constant SIG_VALIDATION_FAILED = 1;


/*
 * For simulation purposes, validateUserOp (and validatePaymasterUserOp)
 * return this value on success.
 */
uint256 constant SIG_VALIDATION_SUCCESS = 0;


/**
 * Returned data from validateUserOp.
 * validateUserOp returns a uint256, which is created by `_packedValidationData` and
 * parsed by `_parseValidationData`.
 * @param aggregator  - address(0) - The account validated the signature by itself.
 *                      address(1) - The account failed to validate the signature.
 *                      otherwise - This is an address of a signature aggregator that must
 *                                  be used to validate the signature.
 * @param validAfter  - This UserOp is valid only after this timestamp.
 * @param validaUntil - This UserOp is valid only up to this timestamp.
 */
struct ValidationData {
    address aggregator;
    uint48 validAfter;
    uint48 validUntil;
}

/**
 * Extract sigFailed, validAfter, validUntil.
 * Also convert zero validUntil to type(uint48).max.
 * @param validationData - The packed validation data.
 */
function _parseValidationData(
    uint256 validationData
) pure returns (ValidationData memory data) {
    address aggregator = address(uint160(validationData));
    uint48 validUntil = uint48(validationData >> 160);
    if (validUntil == 0) {
        validUntil = type(uint48).max;
    }
    uint48 validAfter = uint48(validationData >> (48 + 160));
    return ValidationData(aggregator, validAfter, validUntil);
}

/**
 * Helper to pack the return value for validateUserOp.
 * @param data - The ValidationData to pack.
 */
function _packValidationData(
    ValidationData memory data
) pure returns (uint256) {
    return
        uint160(data.aggregator) |
        (uint256(data.validUntil) << 160) |
        (uint256(data.validAfter) << (160 + 48));
}

/**
 * Helper to pack the return value for validateUserOp, when not using an aggregator.
 * @param sigFailed  - True for signature failure, false for success.
 * @param validUntil - Last timestamp this UserOperation is valid (or zero for infinite).
 * @param validAfter - First timestamp this UserOperation is valid.
 */
function _packValidationData(
    bool sigFailed,
    uint48 validUntil,
    uint48 validAfter
) pure returns (uint256) {
    return
        (sigFailed ? 1 : 0) |
        (uint256(validUntil) << 160) |
        (uint256(validAfter) << (160 + 48));
}

/**
 * keccak function over calldata.
 * @dev copy calldata into memory, do keccak and drop allocated memory. Strangely, this is more efficient than letting solidity do it.
 */
    function calldataKeccak(bytes calldata data) pure returns (bytes32 ret) {
        assembly ("memory-safe") {
            let mem := mload(0x40)
            let len := data.length
            calldatacopy(mem, data.offset, len)
            ret := keccak256(mem, len)
        }
    }


/**
 * The minimum of two numbers.
 * @param a - First number.
 * @param b - Second number.
 */
    function min(uint256 a, uint256 b) pure returns (uint256) {
        return a < b ? a : b;
    }

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.23;

/* solhint-disable no-inline-assembly */

import "../interfaces/PackedUserOperation.sol";
import {calldataKeccak, min} from "./Helpers.sol";

/**
 * Utility functions helpful when working with UserOperation structs.
 */
library UserOperationLib {

    uint256 public constant PAYMASTER_VALIDATION_GAS_OFFSET = 20;
    uint256 public constant PAYMASTER_POSTOP_GAS_OFFSET = 36;
    uint256 public constant PAYMASTER_DATA_OFFSET = 52;
    /**
     * Get sender from user operation data.
     * @param userOp - The user operation data.
     */
    function getSender(
        PackedUserOperation calldata userOp
    ) internal pure returns (address) {
        address data;
        //read sender from userOp, which is first userOp member (saves 800 gas...)
        assembly {
            data := calldataload(userOp)
        }
        return address(uint160(data));
    }

    /**
     * Relayer/block builder might submit the TX with higher priorityFee,
     * but the user should not pay above what he signed for.
     * @param userOp - The user operation data.
     */
    function gasPrice(
        PackedUserOperation calldata userOp
    ) internal view returns (uint256) {
        unchecked {
            (uint256 maxPriorityFeePerGas, uint256 maxFeePerGas) = unpackUints(userOp.gasFees);
            if (maxFeePerGas == maxPriorityFeePerGas) {
                //legacy mode (for networks that don't support basefee opcode)
                return maxFeePerGas;
            }
            return min(maxFeePerGas, maxPriorityFeePerGas + block.basefee);
        }
    }

    /**
     * Pack the user operation data into bytes for hashing.
     * @param userOp - The user operation data.
     */
    function encode(
        PackedUserOperation calldata userOp
    ) internal pure returns (bytes memory ret) {
        address sender = getSender(userOp);
        uint256 nonce = userOp.nonce;
        bytes32 hashInitCode = calldataKeccak(userOp.initCode);
        bytes32 hashCallData = calldataKeccak(userOp.callData);
        bytes32 accountGasLimits = userOp.accountGasLimits;
        uint256 preVerificationGas = userOp.preVerificationGas;
        bytes32 gasFees = userOp.gasFees;
        bytes32 hashPaymasterAndData = calldataKeccak(userOp.paymasterAndData);

        return abi.encode(
            sender, nonce,
            hashInitCode, hashCallData,
            accountGasLimits, preVerificationGas, gasFees,
            hashPaymasterAndData
        );
    }

    function unpackUints(
        bytes32 packed
    ) internal pure returns (uint256 high128, uint256 low128) {
        return (uint128(bytes16(packed)), uint128(uint256(packed)));
    }

    //unpack just the high 128-bits from a packed value
    function unpackHigh128(bytes32 packed) internal pure returns (uint256) {
        return uint256(packed) >> 128;
    }

    // unpack just the low 128-bits from a packed value
    function unpackLow128(bytes32 packed) internal pure returns (uint256) {
        return uint128(uint256(packed));
    }

    function unpackMaxPriorityFeePerGas(PackedUserOperation calldata userOp)
    internal pure returns (uint256) {
        return unpackHigh128(userOp.gasFees);
    }

    function unpackMaxFeePerGas(PackedUserOperation calldata userOp)
    internal pure returns (uint256) {
        return unpackLow128(userOp.gasFees);
    }

    function unpackVerificationGasLimit(PackedUserOperation calldata userOp)
    internal pure returns (uint256) {
        return unpackHigh128(userOp.accountGasLimits);
    }

    function unpackCallGasLimit(PackedUserOperation calldata userOp)
    internal pure returns (uint256) {
        return unpackLow128(userOp.accountGasLimits);
    }

    function unpackPaymasterVerificationGasLimit(PackedUserOperation calldata userOp)
    internal pure returns (uint256) {
        return uint128(bytes16(userOp.paymasterAndData[PAYMASTER_VALIDATION_GAS_OFFSET : PAYMASTER_POSTOP_GAS_OFFSET]));
    }

    function unpackPostOpGasLimit(PackedUserOperation calldata userOp)
    internal pure returns (uint256) {
        return uint128(bytes16(userOp.paymasterAndData[PAYMASTER_POSTOP_GAS_OFFSET : PAYMASTER_DATA_OFFSET]));
    }

    function unpackPaymasterStaticFields(
        bytes calldata paymasterAndData
    ) internal pure returns (address paymaster, uint256 validationGasLimit, uint256 postOpGasLimit) {
        return (
            address(bytes20(paymasterAndData[: PAYMASTER_VALIDATION_GAS_OFFSET])),
            uint128(bytes16(paymasterAndData[PAYMASTER_VALIDATION_GAS_OFFSET : PAYMASTER_POSTOP_GAS_OFFSET])),
            uint128(bytes16(paymasterAndData[PAYMASTER_POSTOP_GAS_OFFSET : PAYMASTER_DATA_OFFSET]))
        );
    }

    /**
     * Hash the user operation data.
     * @param userOp - The user operation data.
     */
    function hash(
        PackedUserOperation calldata userOp
    ) internal pure returns (bytes32) {
        return keccak256(encode(userOp));
    }
}

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.5;

import "./PackedUserOperation.sol";

/**
 * Aggregated Signatures validator.
 */
interface IAggregator {
    /**
     * Validate aggregated signature.
     * Revert if the aggregated signature does not match the given list of operations.
     * @param userOps   - Array of UserOperations to validate the signature for.
     * @param signature - The aggregated signature.
     */
    function validateSignatures(
        PackedUserOperation[] calldata userOps,
        bytes calldata signature
    ) external view;

    /**
     * Validate signature of a single userOp.
     * This method should be called by bundler after EntryPointSimulation.simulateValidation() returns
     * the aggregator this account uses.
     * First it validates the signature over the userOp. Then it returns data to be used when creating the handleOps.
     * @param userOp        - The userOperation received from the user.
     * @return sigForUserOp - The value to put into the signature field of the userOp when calling handleOps.
     *                        (usually empty, unless account and aggregator support some kind of "multisig".
     */
    function validateUserOpSignature(
        PackedUserOperation calldata userOp
    ) external view returns (bytes memory sigForUserOp);

    /**
     * Aggregate multiple signatures into a single value.
     * This method is called off-chain to calculate the signature to pass with handleOps()
     * bundler MAY use optimized custom code perform this aggregation.
     * @param userOps              - Array of UserOperations to collect the signatures from.
     * @return aggregatedSignature - The aggregated signature.
     */
    function aggregateSignatures(
        PackedUserOperation[] calldata userOps
    ) external view returns (bytes memory aggregatedSignature);
}

/**
 ** Account-Abstraction (EIP-4337) singleton EntryPoint implementation.
 ** Only one instance required on each chain.
 **/
// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.5;

/* solhint-disable avoid-low-level-calls */
/* solhint-disable no-inline-assembly */
/* solhint-disable reason-string */

import "./PackedUserOperation.sol";
import "./IStakeManager.sol";
import "./IAggregator.sol";
import "./INonceManager.sol";

interface IEntryPoint is IStakeManager, INonceManager {
    /***
     * An event emitted after each successful request.
     * @param userOpHash    - Unique identifier for the request (hash its entire content, except signature).
     * @param sender        - The account that generates this request.
     * @param paymaster     - If non-null, the paymaster that pays for this request.
     * @param nonce         - The nonce value from the request.
     * @param success       - True if the sender transaction succeeded, false if reverted.
     * @param actualGasCost - Actual amount paid (by account or paymaster) for this UserOperation.
     * @param actualGasUsed - Total gas used by this UserOperation (including preVerification, creation,
     *                        validation and execution).
     */
    event UserOperationEvent(
        bytes32 indexed userOpHash,
        address indexed sender,
        address indexed paymaster,
        uint256 nonce,
        bool success,
        uint256 actualGasCost,
        uint256 actualGasUsed
    );

    /**
     * Account "sender" was deployed.
     * @param userOpHash - The userOp that deployed this account. UserOperationEvent will follow.
     * @param sender     - The account that is deployed
     * @param factory    - The factory used to deploy this account (in the initCode)
     * @param paymaster  - The paymaster used by this UserOp
     */
    event AccountDeployed(
        bytes32 indexed userOpHash,
        address indexed sender,
        address factory,
        address paymaster
    );

    /**
     * An event emitted if the UserOperation "callData" reverted with non-zero length.
     * @param userOpHash   - The request unique identifier.
     * @param sender       - The sender of this request.
     * @param nonce        - The nonce used in the request.
     * @param revertReason - The return bytes from the (reverted) call to "callData".
     */
    event UserOperationRevertReason(
        bytes32 indexed userOpHash,
        address indexed sender,
        uint256 nonce,
        bytes revertReason
    );

    /**
     * An event emitted if the UserOperation Paymaster's "postOp" call reverted with non-zero length.
     * @param userOpHash   - The request unique identifier.
     * @param sender       - The sender of this request.
     * @param nonce        - The nonce used in the request.
     * @param revertReason - The return bytes from the (reverted) call to "callData".
     */
    event PostOpRevertReason(
        bytes32 indexed userOpHash,
        address indexed sender,
        uint256 nonce,
        bytes revertReason
    );

    /**
     * UserOp consumed more than prefund. The UserOperation is reverted, and no refund is made.
     * @param userOpHash   - The request unique identifier.
     * @param sender       - The sender of this request.
     * @param nonce        - The nonce used in the request.
     */
    event UserOperationPrefundTooLow(
        bytes32 indexed userOpHash,
        address indexed sender,
        uint256 nonce
    );

    /**
     * An event emitted by handleOps(), before starting the execution loop.
     * Any event emitted before this event, is part of the validation.
     */
    event BeforeExecution();

    /**
     * Signature aggregator used by the following UserOperationEvents within this bundle.
     * @param aggregator - The aggregator used for the following UserOperationEvents.
     */
    event SignatureAggregatorChanged(address indexed aggregator);

    /**
     * A custom revert error of handleOps, to identify the offending op.
     * Should be caught in off-chain handleOps simulation and not happen on-chain.
     * Useful for mitigating DoS attempts against batchers or for troubleshooting of factory/account/paymaster reverts.
     * NOTE: If simulateValidation passes successfully, there should be no reason for handleOps to fail on it.
     * @param opIndex - Index into the array of ops to the failed one (in simulateValidation, this is always zero).
     * @param reason  - Revert reason. The string starts with a unique code "AAmn",
     *                  where "m" is "1" for factory, "2" for account and "3" for paymaster issues,
     *                  so a failure can be attributed to the correct entity.
     */
    error FailedOp(uint256 opIndex, string reason);

    /**
     * A custom revert error of handleOps, to report a revert by account or paymaster.
     * @param opIndex - Index into the array of ops to the failed one (in simulateValidation, this is always zero).
     * @param reason  - Revert reason. see FailedOp(uint256,string), above
     * @param inner   - data from inner cought revert reason
     * @dev note that inner is truncated to 2048 bytes
     */
    error FailedOpWithRevert(uint256 opIndex, string reason, bytes inner);

    error PostOpReverted(bytes returnData);

    /**
     * Error case when a signature aggregator fails to verify the aggregated signature it had created.
     * @param aggregator The aggregator that failed to verify the signature
     */
    error SignatureValidationFailed(address aggregator);

    // Return value of getSenderAddress.
    error SenderAddressResult(address sender);

    // UserOps handled, per aggregator.
    struct UserOpsPerAggregator {
        PackedUserOperation[] userOps;
        // Aggregator address
        IAggregator aggregator;
        // Aggregated signature
        bytes signature;
    }

    /**
     * Execute a batch of UserOperations.
     * No signature aggregator is used.
     * If any account requires an aggregator (that is, it returned an aggregator when
     * performing simulateValidation), then handleAggregatedOps() must be used instead.
     * @param ops         - The operations to execute.
     * @param beneficiary - The address to receive the fees.
     */
    function handleOps(
        PackedUserOperation[] calldata ops,
        address payable beneficiary
    ) external;

    /**
     * Execute a batch of UserOperation with Aggregators
     * @param opsPerAggregator - The operations to execute, grouped by aggregator (or address(0) for no-aggregator accounts).
     * @param beneficiary      - The address to receive the fees.
     */
    function handleAggregatedOps(
        UserOpsPerAggregator[] calldata opsPerAggregator,
        address payable beneficiary
    ) external;

    /**
     * Generate a request Id - unique identifier for this request.
     * The request ID is a hash over the content of the userOp (except the signature), the entrypoint and the chainid.
     * @param userOp - The user operation to generate the request ID for.
     * @return hash the hash of this UserOperation
     */
    function getUserOpHash(
        PackedUserOperation calldata userOp
    ) external view returns (bytes32);

    /**
     * Gas and return values during simulation.
     * @param preOpGas         - The gas used for validation (including preValidationGas)
     * @param prefund          - The required prefund for this operation
     * @param accountValidationData   - returned validationData from account.
     * @param paymasterValidationData - return validationData from paymaster.
     * @param paymasterContext - Returned by validatePaymasterUserOp (to be passed into postOp)
     */
    struct ReturnInfo {
        uint256 preOpGas;
        uint256 prefund;
        uint256 accountValidationData;
        uint256 paymasterValidationData;
        bytes paymasterContext;
    }

    /**
     * Returned aggregated signature info:
     * The aggregator returned by the account, and its current stake.
     */
    struct AggregatorStakeInfo {
        address aggregator;
        StakeInfo stakeInfo;
    }

    /**
     * Get counterfactual sender address.
     * Calculate the sender contract address that will be generated by the initCode and salt in the UserOperation.
     * This method always revert, and returns the address in SenderAddressResult error
     * @param initCode - The constructor code to be passed into the UserOperation.
     */
    function getSenderAddress(bytes memory initCode) external;

    error DelegateAndRevert(bool success, bytes ret);

    /**
     * Helper method for dry-run testing.
     * @dev calling this method, the EntryPoint will make a delegatecall to the given data, and report (via revert) the result.
     *  The method always revert, so is only useful off-chain for dry run calls, in cases where state-override to replace
     *  actual EntryPoint code is less convenient.
     * @param target a target contract to make a delegatecall from entrypoint
     * @param data data to pass to target in a delegatecall
     */
    function delegateAndRevert(address target, bytes calldata data) external;
}

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.5;

interface INonceManager {

    /**
     * Return the next nonce for this sender.
     * Within a given key, the nonce values are sequenced (starting with zero, and incremented by one on each userop)
     * But UserOp with different keys can come with arbitrary order.
     *
     * @param sender the account address
     * @param key the high 192 bit of the nonce
     * @return nonce a full nonce to pass for next UserOp with this sender.
     */
    function getNonce(address sender, uint192 key)
    external view returns (uint256 nonce);

    /**
     * Manually increment the nonce of the sender.
     * This method is exposed just for completeness..
     * Account does NOT need to call it, neither during validation, nor elsewhere,
     * as the EntryPoint will update the nonce regardless.
     * Possible use-case is call it with various keys to "initialize" their nonces to one, so that future
     * UserOperations will not pay extra for the first transaction with a given key.
     */
    function incrementNonce(uint192 key) external;
}

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.5;

import "./PackedUserOperation.sol";

/**
 * The interface exposed by a paymaster contract, who agrees to pay the gas for user's operations.
 * A paymaster must hold a stake to cover the required entrypoint stake and also the gas for the transaction.
 */
interface IPaymaster {
    enum PostOpMode {
        // User op succeeded.
        opSucceeded,
        // User op reverted. Still has to pay for gas.
        opReverted,
        // Only used internally in the EntryPoint (cleanup after postOp reverts). Never calling paymaster with this value
        postOpReverted
    }

    /**
     * Payment validation: check if paymaster agrees to pay.
     * Must verify sender is the entryPoint.
     * Revert to reject this request.
     * Note that bundlers will reject this method if it changes the state, unless the paymaster is trusted (whitelisted).
     * The paymaster pre-pays using its deposit, and receive back a refund after the postOp method returns.
     * @param userOp          - The user operation.
     * @param userOpHash      - Hash of the user's request data.
     * @param maxCost         - The maximum cost of this transaction (based on maximum gas and gas price from userOp).
     * @return context        - Value to send to a postOp. Zero length to signify postOp is not required.
     * @return validationData - Signature and time-range of this operation, encoded the same as the return
     *                          value of validateUserOperation.
     *                          <20-byte> sigAuthorizer - 0 for valid signature, 1 to mark signature failure,
     *                                                    other values are invalid for paymaster.
     *                          <6-byte> validUntil - last timestamp this operation is valid. 0 for "indefinite"
     *                          <6-byte> validAfter - first timestamp this operation is valid
     *                          Note that the validation code cannot use block.timestamp (or block.number) directly.
     */
    function validatePaymasterUserOp(
        PackedUserOperation calldata userOp,
        bytes32 userOpHash,
        uint256 maxCost
    ) external returns (bytes memory context, uint256 validationData);

    /**
     * Post-operation handler.
     * Must verify sender is the entryPoint.
     * @param mode          - Enum with the following options:
     *                        opSucceeded - User operation succeeded.
     *                        opReverted  - User op reverted. The paymaster still has to pay for gas.
     *                        postOpReverted - never passed in a call to postOp().
     * @param context       - The context value returned by validatePaymasterUserOp
     * @param actualGasCost - Actual gas used so far (without this postOp call).
     * @param actualUserOpFeePerGas - the gas price this UserOp pays. This value is based on the UserOp's maxFeePerGas
     *                        and maxPriorityFee (and basefee)
     *                        It is not the same as tx.gasprice, which is what the bundler pays.
     */
    function postOp(
        PostOpMode mode,
        bytes calldata context,
        uint256 actualGasCost,
        uint256 actualUserOpFeePerGas
    ) external;
}

// SPDX-License-Identifier: GPL-3.0-only
pragma solidity >=0.7.5;

/**
 * Manage deposits and stakes.
 * Deposit is just a balance used to pay for UserOperations (either by a paymaster or an account).
 * Stake is value locked for at least "unstakeDelay" by the staked entity.
 */
interface IStakeManager {
    event Deposited(address indexed account, uint256 totalDeposit);

    event Withdrawn(
        address indexed account,
        address withdrawAddress,
        uint256 amount
    );

    // Emitted when stake or unstake delay are modified.
    event StakeLocked(
        address indexed account,
        uint256 totalStaked,
        uint256 unstakeDelaySec
    );

    // Emitted once a stake is scheduled for withdrawal.
    event StakeUnlocked(address indexed account, uint256 withdrawTime);

    event StakeWithdrawn(
        address indexed account,
        address withdrawAddress,
        uint256 amount
    );

    /**
     * @param deposit         - The entity's deposit.
     * @param staked          - True if this entity is staked.
     * @param stake           - Actual amount of ether staked for this entity.
     * @param unstakeDelaySec - Minimum delay to withdraw the stake.
     * @param withdrawTime    - First block timestamp where 'withdrawStake' will be callable, or zero if already locked.
     * @dev Sizes were chosen so that deposit fits into one cell (used during handleOp)
     *      and the rest fit into a 2nd cell (used during stake/unstake)
     *      - 112 bit allows for 10^15 eth
     *      - 48 bit for full timestamp
     *      - 32 bit allows 150 years for unstake delay
     */
    struct DepositInfo {
        uint256 deposit;
        bool staked;
        uint112 stake;
        uint32 unstakeDelaySec;
        uint48 withdrawTime;
    }

    // API struct used by getStakeInfo and simulateValidation.
    struct StakeInfo {
        uint256 stake;
        uint256 unstakeDelaySec;
    }

    /**
     * Get deposit info.
     * @param account - The account to query.
     * @return info   - Full deposit information of given account.
     */
    function getDepositInfo(
        address account
    ) external view returns (DepositInfo memory info);

    /**
     * Get account balance.
     * @param account - The account to query.
     * @return        - The deposit (for gas payment) of the account.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * Add to the deposit of the given account.
     * @param account - The account to add to.
     */
    function depositTo(address account) external payable;

    /**
     * Add to the account's stake - amount and delay
     * any pending unstake is first cancelled.
     * @param _unstakeDelaySec - The new lock duration before the deposit can be withdrawn.
     */
    function addStake(uint32 _unstakeDelaySec) external payable;

    /**
     * Attempt to unlock the stake.
     * The value can be withdrawn (using withdrawStake) after the unstake delay.
     */
    function unlockStake() external;

    /**
     * Withdraw from the (unlocked) stake.
     * Must first call unlockStake and wait for the unstakeDelay to pass.
     * @param withdrawAddress - The address to send withdrawn value.
     */
    function withdrawStake(address payable withdrawAddress) external;

    /**
     * Withdraw from the deposit.
     * @param withdrawAddress - The address to send withdrawn value.
     * @param withdrawAmount  - The amount to withdraw.
     */
    function withdrawTo(
        address payable withdrawAddress,
        uint256 withdrawAmount
    ) external;
}

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.5;

/**
 * User Operation struct
 * @param sender                - The sender account of this request.
 * @param nonce                 - Unique value the sender uses to verify it is not a replay.
 * @param initCode              - If set, the account contract will be created by this constructor/
 * @param callData              - The method call to execute on this account.
 * @param accountGasLimits      - Packed gas limits for validateUserOp and gas limit passed to the callData method call.
 * @param preVerificationGas    - Gas not calculated by the handleOps method, but added to the gas paid.
 *                                Covers batch overhead.
 * @param gasFees               - packed gas fields maxPriorityFeePerGas and maxFeePerGas - Same as EIP-1559 gas parameters.
 * @param paymasterAndData      - If set, this field holds the paymaster address, verification gas limit, postOp gas limit and paymaster-specific extra data
 *                                The paymaster will pay for the transaction instead of the sender.
 * @param signature             - Sender-verified signature over the entire request, the EntryPoint address and the chain ID.
 */
struct PackedUserOperation {
    address sender;
    uint256 nonce;
    bytes initCode;
    bytes callData;
    bytes32 accountGasLimits;
    uint256 preVerificationGas;
    bytes32 gasFees;
    bytes paymasterAndData;
    bytes signature;
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface AggregatorV3Interface {
  function decimals() external view returns (uint8);

  function description() external view returns (string memory);

  function version() external view returns (uint256);

  function getRoundData(uint80 _roundId)
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );

  function latestRoundData()
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (access/Ownable.sol)

pragma solidity ^0.8.20;

import {Context} from "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * The initial owner is set to the address provided by the deployer. This can
 * later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    /**
     * @dev The caller account is not authorized to perform an operation.
     */
    error OwnableUnauthorizedAccount(address account);

    /**
     * @dev The owner is not a valid owner account. (eg. `address(0)`)
     */
    error OwnableInvalidOwner(address owner);

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the address provided by the deployer as the initial owner.
     */
    constructor(address initialOwner) {
        if (initialOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(initialOwner);
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        if (owner() != _msgSender()) {
            revert OwnableUnauthorizedAccount(_msgSender());
        }
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        if (newOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.20;

import {IERC20} from "../IERC20.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/extensions/IERC20Permit.sol)

pragma solidity ^0.8.20;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 *
 * ==== Security Considerations
 *
 * There are two important considerations concerning the use of `permit`. The first is that a valid permit signature
 * expresses an allowance, and it should not be assumed to convey additional meaning. In particular, it should not be
 * considered as an intention to spend the allowance in any specific way. The second is that because permits have
 * built-in replay protection and can be submitted by anyone, they can be frontrun. A protocol that uses permits should
 * take this into consideration and allow a `permit` call to fail. Combining these two aspects, a pattern that may be
 * generally recommended is:
 *
 * ```solidity
 * function doThingWithPermit(..., uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) public {
 *     try token.permit(msg.sender, address(this), value, deadline, v, r, s) {} catch {}
 *     doThing(..., value);
 * }
 *
 * function doThing(..., uint256 value) public {
 *     token.safeTransferFrom(msg.sender, address(this), value);
 *     ...
 * }
 * ```
 *
 * Observe that: 1) `msg.sender` is used as the owner, leaving no ambiguity as to the signer intent, and 2) the use of
 * `try/catch` allows the permit to fail and makes the code tolerant to frontrunning. (See also
 * {SafeERC20-safeTransferFrom}).
 *
 * Additionally, note that smart contract wallets (such as Argent or Safe) are not able to produce permit signatures, so
 * contracts should have entry points that don't rely on permit.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     *
     * CAUTION: See Security Considerations above.
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.20;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the value of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the value of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves a `value` amount of tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 value) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets a `value` amount of tokens as the allowance of `spender` over the
     * caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the
     * allowance mechanism. `value` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 value) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.20;

import {IERC20} from "../IERC20.sol";
import {IERC20Permit} from "../extensions/IERC20Permit.sol";
import {Address} from "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    /**
     * @dev An operation with an ERC20 token failed.
     */
    error SafeERC20FailedOperation(address token);

    /**
     * @dev Indicates a failed `decreaseAllowance` request.
     */
    error SafeERC20FailedDecreaseAllowance(address spender, uint256 currentAllowance, uint256 requestedDecrease);

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeCall(token.transfer, (to, value)));
    }

    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeCall(token.transferFrom, (from, to, value)));
    }

    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        forceApprove(token, spender, oldAllowance + value);
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `requestedDecrease`. If `token` returns no
     * value, non-reverting calls are assumed to be successful.
     */
    function safeDecreaseAllowance(IERC20 token, address spender, uint256 requestedDecrease) internal {
        unchecked {
            uint256 currentAllowance = token.allowance(address(this), spender);
            if (currentAllowance < requestedDecrease) {
                revert SafeERC20FailedDecreaseAllowance(spender, currentAllowance, requestedDecrease);
            }
            forceApprove(token, spender, currentAllowance - requestedDecrease);
        }
    }

    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval
     * to be set to zero before setting it to a non-zero value, such as USDT.
     */
    function forceApprove(IERC20 token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeCall(token.approve, (spender, value));

        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeCall(token.approve, (spender, 0)));
            _callOptionalReturn(token, approvalCall);
        }
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data);
        if (returndata.length != 0 && !abi.decode(returndata, (bool))) {
            revert SafeERC20FailedOperation(address(token));
        }
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     *
     * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We cannot use {Address-functionCall} here since this should return false
        // and not revert is the subcall reverts.

        (bool success, bytes memory returndata) = address(token).call(data);
        return success && (returndata.length == 0 || abi.decode(returndata, (bool))) && address(token).code.length > 0;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/Address.sol)

pragma solidity ^0.8.20;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev The ETH balance of the account is not enough to perform the operation.
     */
    error AddressInsufficientBalance(address account);

    /**
     * @dev There's no code at `target` (it is not a contract).
     */
    error AddressEmptyCode(address target);

    /**
     * @dev A call to an address target failed. The target may have reverted.
     */
    error FailedInnerCall();

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.8.20/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        if (address(this).balance < amount) {
            revert AddressInsufficientBalance(address(this));
        }

        (bool success, ) = recipient.call{value: amount}("");
        if (!success) {
            revert FailedInnerCall();
        }
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason or custom error, it is bubbled
     * up by this function (like regular Solidity function calls). However, if
     * the call reverted with no returned reason, this function reverts with a
     * {FailedInnerCall} error.
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        if (address(this).balance < value) {
            revert AddressInsufficientBalance(address(this));
        }
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and reverts if the target
     * was not a contract or bubbling up the revert reason (falling back to {FailedInnerCall}) in case of an
     * unsuccessful call.
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata
    ) internal view returns (bytes memory) {
        if (!success) {
            _revert(returndata);
        } else {
            // only check if target is a contract if the call was successful and the return data is empty
            // otherwise we already know that it was a contract
            if (returndata.length == 0 && target.code.length == 0) {
                revert AddressEmptyCode(target);
            }
            return returndata;
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and reverts if it wasn't, either by bubbling the
     * revert reason or with a default {FailedInnerCall} error.
     */
    function verifyCallResult(bool success, bytes memory returndata) internal pure returns (bytes memory) {
        if (!success) {
            _revert(returndata);
        } else {
            return returndata;
        }
    }

    /**
     * @dev Reverts with returndata if present. Otherwise reverts with {FailedInnerCall}.
     */
    function _revert(bytes memory returndata) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert FailedInnerCall();
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)

pragma solidity ^0.8.20;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    function _contextSuffixLength() internal view virtual returns (uint256) {
        return 0;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/cryptography/ECDSA.sol)

pragma solidity ^0.8.20;

/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSA {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS
    }

    /**
     * @dev The signature derives the `address(0)`.
     */
    error ECDSAInvalidSignature();

    /**
     * @dev The signature has an invalid length.
     */
    error ECDSAInvalidSignatureLength(uint256 length);

    /**
     * @dev The signature has an S value that is in the upper half order.
     */
    error ECDSAInvalidSignatureS(bytes32 s);

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with `signature` or an error. This will not
     * return address(0) without also returning an error description. Errors are documented using an enum (error type)
     * and a bytes32 providing additional information about the error.
     *
     * If no error is returned, then the address can be used for verification purposes.
     *
     * The `ecrecover` EVM precompile allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {MessageHashUtils-toEthSignedMessageHash} on it.
     *
     * Documentation for signature generation:
     * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
     * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
     */
    function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError, bytes32) {
        if (signature.length == 65) {
            bytes32 r;
            bytes32 s;
            uint8 v;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            /// @solidity memory-safe-assembly
            assembly {
                r := mload(add(signature, 0x20))
                s := mload(add(signature, 0x40))
                v := byte(0, mload(add(signature, 0x60)))
            }
            return tryRecover(hash, v, r, s);
        } else {
            return (address(0), RecoverError.InvalidSignatureLength, bytes32(signature.length));
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM precompile allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {MessageHashUtils-toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        (address recovered, RecoverError error, bytes32 errorArg) = tryRecover(hash, signature);
        _throwError(error, errorArg);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
     *
     * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
     */
    function tryRecover(bytes32 hash, bytes32 r, bytes32 vs) internal pure returns (address, RecoverError, bytes32) {
        unchecked {
            bytes32 s = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
            // We do not check for an overflow here since the shift operation results in 0 or 1.
            uint8 v = uint8((uint256(vs) >> 255) + 27);
            return tryRecover(hash, v, r, s);
        }
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
     */
    function recover(bytes32 hash, bytes32 r, bytes32 vs) internal pure returns (address) {
        (address recovered, RecoverError error, bytes32 errorArg) = tryRecover(hash, r, vs);
        _throwError(error, errorArg);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function tryRecover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address, RecoverError, bytes32) {
        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return (address(0), RecoverError.InvalidSignatureS, s);
        }

        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        if (signer == address(0)) {
            return (address(0), RecoverError.InvalidSignature, bytes32(0));
        }

        return (signer, RecoverError.NoError, bytes32(0));
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function recover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) internal pure returns (address) {
        (address recovered, RecoverError error, bytes32 errorArg) = tryRecover(hash, v, r, s);
        _throwError(error, errorArg);
        return recovered;
    }

    /**
     * @dev Optionally reverts with the corresponding custom error according to the `error` argument provided.
     */
    function _throwError(RecoverError error, bytes32 errorArg) private pure {
        if (error == RecoverError.NoError) {
            return; // no error: do nothing
        } else if (error == RecoverError.InvalidSignature) {
            revert ECDSAInvalidSignature();
        } else if (error == RecoverError.InvalidSignatureLength) {
            revert ECDSAInvalidSignatureLength(uint256(errorArg));
        } else if (error == RecoverError.InvalidSignatureS) {
            revert ECDSAInvalidSignatureS(errorArg);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/cryptography/MessageHashUtils.sol)

pragma solidity ^0.8.20;

import {Strings} from "../Strings.sol";

/**
 * @dev Signature message hash utilities for producing digests to be consumed by {ECDSA} recovery or signing.
 *
 * The library provides methods for generating a hash of a message that conforms to the
 * https://eips.ethereum.org/EIPS/eip-191[EIP 191] and https://eips.ethereum.org/EIPS/eip-712[EIP 712]
 * specifications.
 */
library MessageHashUtils {
    /**
     * @dev Returns the keccak256 digest of an EIP-191 signed data with version
     * `0x45` (`personal_sign` messages).
     *
     * The digest is calculated by prefixing a bytes32 `messageHash` with
     * `"\x19Ethereum Signed Message:\n32"` and hashing the result. It corresponds with the
     * hash signed when using the https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`] JSON-RPC method.
     *
     * NOTE: The `messageHash` parameter is intended to be the result of hashing a raw message with
     * keccak256, although any bytes32 value can be safely used because the final digest will
     * be re-hashed.
     *
     * See {ECDSA-recover}.
     */
    function toEthSignedMessageHash(bytes32 messageHash) internal pure returns (bytes32 digest) {
        /// @solidity memory-safe-assembly
        assembly {
            mstore(0x00, "\x19Ethereum Signed Message:\n32") // 32 is the bytes-length of messageHash
            mstore(0x1c, messageHash) // 0x1c (28) is the length of the prefix
            digest := keccak256(0x00, 0x3c) // 0x3c is the length of the prefix (0x1c) + messageHash (0x20)
        }
    }

    /**
     * @dev Returns the keccak256 digest of an EIP-191 signed data with version
     * `0x45` (`personal_sign` messages).
     *
     * The digest is calculated by prefixing an arbitrary `message` with
     * `"\x19Ethereum Signed Message:\n" + len(message)` and hashing the result. It corresponds with the
     * hash signed when using the https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`] JSON-RPC method.
     *
     * See {ECDSA-recover}.
     */
    function toEthSignedMessageHash(bytes memory message) internal pure returns (bytes32) {
        return
            keccak256(bytes.concat("\x19Ethereum Signed Message:\n", bytes(Strings.toString(message.length)), message));
    }

    /**
     * @dev Returns the keccak256 digest of an EIP-191 signed data with version
     * `0x00` (data with intended validator).
     *
     * The digest is calculated by prefixing an arbitrary `data` with `"\x19\x00"` and the intended
     * `validator` address. Then hashing the result.
     *
     * See {ECDSA-recover}.
     */
    function toDataWithIntendedValidatorHash(address validator, bytes memory data) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked(hex"19_00", validator, data));
    }

    /**
     * @dev Returns the keccak256 digest of an EIP-712 typed data (EIP-191 version `0x01`).
     *
     * The digest is calculated from a `domainSeparator` and a `structHash`, by prefixing them with
     * `\x19\x01` and hashing the result. It corresponds to the hash signed by the
     * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`] JSON-RPC method as part of EIP-712.
     *
     * See {ECDSA-recover}.
     */
    function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32 digest) {
        /// @solidity memory-safe-assembly
        assembly {
            let ptr := mload(0x40)
            mstore(ptr, hex"19_01")
            mstore(add(ptr, 0x02), domainSeparator)
            mstore(add(ptr, 0x22), structHash)
            digest := keccak256(ptr, 0x42)
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/introspection/IERC165.sol)

pragma solidity ^0.8.20;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/math/Math.sol)

pragma solidity ^0.8.20;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Muldiv operation overflow.
     */
    error MathOverflowedMulDiv();

    enum Rounding {
        Floor, // Toward negative infinity
        Ceil, // Toward positive infinity
        Trunc, // Toward zero
        Expand // Away from zero
    }

    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, with an overflow flag.
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
            // benefit is lost if 'b' is also tested.
            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds towards infinity instead
     * of rounding towards zero.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        if (b == 0) {
            // Guarantee the same behavior as in a regular Solidity division.
            return a / b;
        }

        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or
     * denominator == 0.
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv) with further edits by
     * Uniswap Labs also under MIT license.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0 = x * y; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                // The surrounding unchecked block does not change this fact.
                // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            if (denominator <= prod1) {
                revert MathOverflowedMulDiv();
            }

            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator.
            // Always >= 1. See https://cs.stackexchange.com/q/138556/92363.

            uint256 twos = denominator & (0 - denominator);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;

            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;

            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also
            // works in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256

            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (unsignedRoundsUp(rounding) && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded
     * towards zero.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (unsignedRoundsUp(rounding) && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2 of a positive value rounded towards zero.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (unsignedRoundsUp(rounding) && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10 of a positive value rounded towards zero.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10 ** 64) {
                value /= 10 ** 64;
                result += 64;
            }
            if (value >= 10 ** 32) {
                value /= 10 ** 32;
                result += 32;
            }
            if (value >= 10 ** 16) {
                value /= 10 ** 16;
                result += 16;
            }
            if (value >= 10 ** 8) {
                value /= 10 ** 8;
                result += 8;
            }
            if (value >= 10 ** 4) {
                value /= 10 ** 4;
                result += 4;
            }
            if (value >= 10 ** 2) {
                value /= 10 ** 2;
                result += 2;
            }
            if (value >= 10 ** 1) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (unsignedRoundsUp(rounding) && 10 ** result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256 of a positive value rounded towards zero.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (unsignedRoundsUp(rounding) && 1 << (result << 3) < value ? 1 : 0);
        }
    }

    /**
     * @dev Returns whether a provided rounding mode is considered rounding up for unsigned integers.
     */
    function unsignedRoundsUp(Rounding rounding) internal pure returns (bool) {
        return uint8(rounding) % 2 == 1;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/math/SignedMath.sol)

pragma solidity ^0.8.20;

/**
 * @dev Standard signed math utilities missing in the Solidity language.
 */
library SignedMath {
    /**
     * @dev Returns the largest of two signed numbers.
     */
    function max(int256 a, int256 b) internal pure returns (int256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two signed numbers.
     */
    function min(int256 a, int256 b) internal pure returns (int256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two signed numbers without overflow.
     * The result is rounded towards zero.
     */
    function average(int256 a, int256 b) internal pure returns (int256) {
        // Formula from the book "Hacker's Delight"
        int256 x = (a & b) + ((a ^ b) >> 1);
        return x + (int256(uint256(x) >> 255) & (a ^ b));
    }

    /**
     * @dev Returns the absolute unsigned value of a signed value.
     */
    function abs(int256 n) internal pure returns (uint256) {
        unchecked {
            // must be unchecked in order to support `n = type(int256).min`
            return uint256(n >= 0 ? n : -n);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/Strings.sol)

pragma solidity ^0.8.20;

import {Math} from "./math/Math.sol";
import {SignedMath} from "./math/SignedMath.sol";

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant HEX_DIGITS = "0123456789abcdef";
    uint8 private constant ADDRESS_LENGTH = 20;

    /**
     * @dev The `value` string doesn't fit in the specified `length`.
     */
    error StringsInsufficientHexLength(uint256 value, uint256 length);

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        unchecked {
            uint256 length = Math.log10(value) + 1;
            string memory buffer = new string(length);
            uint256 ptr;
            /// @solidity memory-safe-assembly
            assembly {
                ptr := add(buffer, add(32, length))
            }
            while (true) {
                ptr--;
                /// @solidity memory-safe-assembly
                assembly {
                    mstore8(ptr, byte(mod(value, 10), HEX_DIGITS))
                }
                value /= 10;
                if (value == 0) break;
            }
            return buffer;
        }
    }

    /**
     * @dev Converts a `int256` to its ASCII `string` decimal representation.
     */
    function toStringSigned(int256 value) internal pure returns (string memory) {
        return string.concat(value < 0 ? "-" : "", toString(SignedMath.abs(value)));
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        unchecked {
            return toHexString(value, Math.log256(value) + 1);
        }
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        uint256 localValue = value;
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = HEX_DIGITS[localValue & 0xf];
            localValue >>= 4;
        }
        if (localValue != 0) {
            revert StringsInsufficientHexLength(value, length);
        }
        return string(buffer);
    }

    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal
     * representation.
     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), ADDRESS_LENGTH);
    }

    /**
     * @dev Returns true if the two strings are equal.
     */
    function equal(string memory a, string memory b) internal pure returns (bool) {
        return bytes(a).length == bytes(b).length && keccak256(bytes(a)) == keccak256(bytes(b));
    }
}

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.20;

/// @author CandideWallet Team

import {BytesLib} from "./utils/BytesLib.sol";
import "@account-abstraction-07/contracts/core/BasePaymaster.sol";
import "@account-abstraction-07/contracts/core/Helpers.sol";
import "@account-abstraction-07/contracts/interfaces/IEntryPoint.sol";

import "@openzeppelin/contracts/utils/cryptography/MessageHashUtils.sol";
import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import { Math } from "@openzeppelin/contracts/utils/math/Math.sol";

import {AggregatorV3Interface} from "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";

contract CandidePaymaster07 is BasePaymaster {

    using ECDSA for bytes32;
    using UserOperationLib for PackedUserOperation;
    using SafeERC20 for IERC20Metadata;

    enum SponsoringMode {
        TOKEN_WITH_EXCHANGE, // exchange rate is embedded in the paymasterAndData and not using the cachedExchangeRate on-chain
        TOKEN,
        FREE
    }

    enum PriceMarkupMode {
        NO_MARKUP,
        INCLUDE,
        INCLUDE_CUSTOM
    }

    enum OracleType {
        CHAINLINK,
        UNISWAP
    }

    struct PaymasterData {
        SponsoringMode mode;
        PriceMarkupMode priceMarkupMode;
        GasToken gasToken;
        uint256 exchangeRate;
        uint256 priceMarkup;
        uint48 validUntil;
        bytes signature;
    }

    struct GasToken {
        IERC20Metadata token;
        OracleType oracleType;
        bytes oracle;
        uint256 cachedExchangeRate;
        uint256 priceMarkup;
    }

    //
    uint256 private constant PRICE_DENOMINATOR = 100000000000000000000000000;
    uint256 constant public COST_OF_POST = 35000;
    //
    mapping (uint8 => GasToken) internal gasTokens;
    //
    event PostOpReverted(bytes32 indexed userOpHash, address indexed sender, address indexed token);
    event UserOperationSponsored(bytes32 indexed userOpHash, address indexed sender, address indexed token, uint256 cost);

    constructor(IEntryPoint _entryPoint, address _owner) BasePaymaster(_entryPoint) {
        _transferOwnership(_owner);
    }

    /**
     * withdraw tokens.
     * @param token the token deposit to withdraw
     * @param target address to send to
     * @param amount amount to withdraw
     */

    function withdrawTokensTo(IERC20Metadata token, address target, uint256 amount) public {
        require(owner() == msg.sender, "CP00: only owner can withdraw tokens");
        token.safeTransfer(target, amount);
    }

    function addSupportedToken(uint8 slot, GasToken calldata token) public {
        require(owner() == msg.sender, "CP01: only owner can add supported tokens");
        gasTokens[slot] = token;
    }

    function revokeSupportedToken(uint8 slot) public {
        require(owner() == msg.sender, "CP02: only owner can revoke supported tokens");
        delete gasTokens[slot];
    }

    function _getChainlinkDerivedExchangeRate(
        address _base,
        address _quote,
        uint8 _decimals
    ) internal view returns (int256) {
        require(
            _decimals > uint8(0) && _decimals <= uint8(18),
            "Invalid _decimals"
        );
        int256 decimals = int256(10 ** uint256(_decimals));
        (, int256 basePrice, , , ) = AggregatorV3Interface(_base).latestRoundData();
        uint8 baseDecimals = AggregatorV3Interface(_base).decimals();
        basePrice = _scalePrice(basePrice, baseDecimals, _decimals);

        (, int256 quotePrice, , , ) = AggregatorV3Interface(_quote).latestRoundData();
        uint8 quoteDecimals = AggregatorV3Interface(_quote).decimals();
        quotePrice = _scalePrice(quotePrice, quoteDecimals, _decimals);

        return (basePrice * decimals) / quotePrice;
    }

    function _scalePrice(
        int256 _price,
        uint8 _priceDecimals,
        uint8 _decimals
    ) internal pure returns (int256) {
        if (_priceDecimals < _decimals) {
            return _price * int256(10 ** uint256(_decimals - _priceDecimals));
        } else if (_priceDecimals > _decimals) {
            return _price / int256(10 ** uint256(_priceDecimals - _decimals));
        }
        return _price;
    }

    function getTokenExchangeRate(uint8 slot) public view returns (uint256) {
        GasToken memory gasToken = gasTokens[slot];
        if (address(gasToken.token) == address(0)){
            return 0;
        }
        uint256 exchangeRate;
        if (gasToken.oracleType == OracleType.CHAINLINK){
            address baseTokenOracle = address(bytes20(BytesLib.slice(gasToken.oracle, 0, 20)));
            address quoteTokenOracle = address(bytes20(BytesLib.slice(gasToken.oracle, 20, 40)));
            uint8 decimals = gasToken.token.decimals();
            exchangeRate = uint256(_getChainlinkDerivedExchangeRate(baseTokenOracle, quoteTokenOracle, decimals));
        }else{
            address pool = address(bytes20(BytesLib.slice(gasToken.oracle, 0, 20)));
            // todo
        }
        return exchangeRate;
    }

    function getTokens(uint8[] calldata slots) public view returns (GasToken[] memory) {
        GasToken[] memory result = new GasToken[](slots.length);
        for (uint i=0; i<slots.length; i++){
            uint8 slot = slots[i];
            result[i] = gasTokens[slot];
        }
        return result;
    }

    function updateTokensExchangeRates(uint8[] calldata slots) public {
        for (uint i=0; i<slots.length; i++){
            uint8 slot = slots[i];
            uint256 exchangeRate = getTokenExchangeRate(slot);
            if (exchangeRate > 0) {
                GasToken storage gasToken = gasTokens[slot];
                gasToken.cachedExchangeRate = exchangeRate;
            }
        }
    }

    function pack(PackedUserOperation calldata userOp) internal pure returns (bytes32) {
        return keccak256(abi.encode(
            userOp.sender,
            userOp.nonce,
            keccak256(userOp.initCode),
            keccak256(userOp.callData),
            userOp.accountGasLimits,
            userOp.preVerificationGas,
            userOp.gasFees
        ));
    }


    /**
     * return the hash we're going to sign off-chain (and validate on-chain)
     * this method is called by the off-chain service, to sign the request.
     * it is called on-chain from the validatePaymasterUserOp, to validate the signature.
     */
    function getHash(PackedUserOperation calldata userOp, PaymasterData memory paymasterData) public view returns (bytes32) {
        (, uint256 pmValidationGasLimit, uint256 pmPostOpGasLimit) = UserOperationLib.unpackPaymasterStaticFields(userOp.paymasterAndData);
        bytes32 hash = keccak256(abi.encode(
            pack(userOp),
            block.chainid,
            address(this),
            paymasterData.mode,
            paymasterData.priceMarkupMode,
            paymasterData.validUntil,
            pmValidationGasLimit,
            pmPostOpGasLimit
        ));
        if (paymasterData.mode != SponsoringMode.FREE){
            hash = keccak256(abi.encode(hash, address(paymasterData.gasToken.token)));
        }
        if (paymasterData.mode == SponsoringMode.TOKEN_WITH_EXCHANGE){
            hash = keccak256(abi.encode(hash, paymasterData.exchangeRate));
        }
        if (paymasterData.priceMarkupMode == PriceMarkupMode.INCLUDE_CUSTOM){
            hash = keccak256(abi.encode(hash, paymasterData.priceMarkup));
        }
        return hash;
    }

    function _getPriceMarkupAndSignature(PriceMarkupMode priceMarkupMode, GasToken memory gasToken, uint256 startLocation, bytes calldata paymasterAndData) internal pure returns (uint256, bytes memory){
        uint256 priceMarkup = PRICE_DENOMINATOR;
        bytes memory signature;
        if (priceMarkupMode == PriceMarkupMode.INCLUDE){
            priceMarkup = gasToken.priceMarkup;
            signature = bytes(paymasterAndData[startLocation:]);
        }else if (priceMarkupMode == PriceMarkupMode.INCLUDE_CUSTOM){
            priceMarkup = uint256(bytes32(paymasterAndData[startLocation:startLocation+32]));
            signature = bytes(paymasterAndData[startLocation+32:]);
        }else if (priceMarkupMode == PriceMarkupMode.NO_MARKUP){
            signature = bytes(paymasterAndData[startLocation:]);
        }
        return (priceMarkup, signature);
    }

    function parsePaymasterAndData(bytes calldata paymasterAndData) public view returns (PaymasterData memory) {
        SponsoringMode mode = SponsoringMode(uint8(bytes1(paymasterAndData[0:1])));
        PriceMarkupMode priceMarkupMode = PriceMarkupMode(uint8(bytes1(paymasterAndData[1:2])));
        GasToken memory token = gasTokens[0];
        uint256 exchangeRate = 0;
        uint256 priceMarkup = PRICE_DENOMINATOR;
        uint48 validUntil;
        bytes memory signature;
        if (mode == SponsoringMode.TOKEN_WITH_EXCHANGE){
            uint8 gasTokenSlot = uint8(bytes1(paymasterAndData[2:3]));
            validUntil = uint48(bytes6(paymasterAndData[3:9]));
            exchangeRate = uint256(bytes32(paymasterAndData[9:41]));
            token = gasTokens[gasTokenSlot];
            (priceMarkup, signature) = _getPriceMarkupAndSignature(priceMarkupMode, token, 41, paymasterAndData);
        }else if (mode == SponsoringMode.TOKEN){
            uint8 gasTokenSlot = uint8(bytes1(paymasterAndData[2:3]));
            validUntil = uint48(bytes6(paymasterAndData[3:9]));
            token = gasTokens[gasTokenSlot];
            exchangeRate = token.cachedExchangeRate;
            (priceMarkup, signature) = _getPriceMarkupAndSignature(priceMarkupMode, token, 9, paymasterAndData);
        } else if (mode == SponsoringMode.FREE){
            validUntil = uint48(bytes6(paymasterAndData[2:8]));
            signature = bytes(paymasterAndData[8:]);
        }
        return PaymasterData(mode, priceMarkupMode, token, exchangeRate, priceMarkup, validUntil, signature);
    }

    /**
     * Verify our external signer signed this request and decode paymasterData
     * paymasterData contains the following:
     * token address length 20
     * signature length 64 or 65 or empty in case of SponsoringMode == GAS_BACK
     */
    function _validatePaymasterUserOp(PackedUserOperation calldata userOp, bytes32 userOpHash, uint256 maxCost)
    internal virtual override returns (bytes memory context, uint256 validationData){
        PaymasterData memory paymasterData = parsePaymasterAndData(userOp.paymasterAndData[UserOperationLib.PAYMASTER_DATA_OFFSET:]);
        require(paymasterData.signature.length == 64 || paymasterData.signature.length == 65, "CP01: invalid signature length in paymasterAndData");
        address account = userOp.getSender();
        uint256 maxUseropCost = maxCost + (COST_OF_POST * userOp.unpackMaxFeePerGas());
        uint256 tokenExchangeRate = paymasterData.exchangeRate;
        if (paymasterData.mode != SponsoringMode.FREE){
            if (paymasterData.priceMarkup > 0){
                tokenExchangeRate = (paymasterData.exchangeRate * paymasterData.priceMarkup) / PRICE_DENOMINATOR ;
            }
            uint256 accountBalance = paymasterData.gasToken.token.balanceOf(account);
            uint256 maxTokenCost = (maxUseropCost * tokenExchangeRate) / 1e18;
            if (accountBalance < maxTokenCost){
                return ("", _packValidationData(true, paymasterData.validUntil, 0));
            }
        }
        bytes32 _hash = MessageHashUtils.toEthSignedMessageHash(getHash(userOp, paymasterData));
        if (owner() != _hash.recover(paymasterData.signature)) {
            return ("", _packValidationData(true, paymasterData.validUntil, 0));
        }

        bytes memory _context = abi.encode(
            account,
            userOpHash,
            paymasterData.mode,
            paymasterData.gasToken.token,
            tokenExchangeRate
        );

        return (_context, _packValidationData(false, paymasterData.validUntil, 0));
    }


    /**
     * Perform the post-operation to charge the sender for the gas.
     */
    function _postOp(PostOpMode, bytes calldata context, uint256 actualGasCost, uint256 actualUserOpFeePerGas) internal virtual override {
        (
            address account,
            bytes32 userOpHash,
            SponsoringMode sponsoringMode,
            IERC20Metadata token,
            uint256 exchangeRate
        ) = abi.decode(context, (address, bytes32, SponsoringMode, IERC20Metadata, uint256));
        if (sponsoringMode == SponsoringMode.FREE){
            emit UserOperationSponsored(userOpHash, account, address(0), 0);
            return;
        }
        //
        uint256 actualETHCost = actualGasCost + (COST_OF_POST * actualUserOpFeePerGas);
        uint256 actualTokenCost = (actualETHCost * exchangeRate) / 1e18;
        //
        bool success = _callAndReturn(token, abi.encodeCall(token.transferFrom, (account, address(this), actualTokenCost)));
        if (!success){
            emit PostOpReverted(userOpHash, account, address(token));
            return;
        }
        emit UserOperationSponsored(userOpHash, account, address(token), actualTokenCost);
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     *
     */
    function _callAndReturn(IERC20Metadata token, bytes memory data) internal returns (bool) {
        bool success;
        uint256 returnSize;
        uint256 returnValue;
        assembly ("memory-safe") {
            success := call(gas(), token, 0, add(data, 0x20), mload(data), 0, 0x20)
            returnSize := returndatasize()
            returnValue := mload(0)
        }
        return success && (returnSize == 0 ? address(token).code.length > 0 : returnValue == 1);
    }
}

// SPDX-License-Identifier: Unlicense
/*
 * @title Solidity Bytes Arrays Utils
 * @author Gonçalo Sá <goncalo.sa@consensys.net>
 *
 * @dev Bytes tightly packed arrays utility library for ethereum contracts written in Solidity.
 *      The library lets you concatenate, slice and type cast bytes arrays both in memory and storage.
 */
pragma solidity >=0.8.0 <0.9.0;


library BytesLib {
    function concat(
        bytes memory _preBytes,
        bytes memory _postBytes
    )
    internal
    pure
    returns (bytes memory)
    {
        bytes memory tempBytes;

        assembly {
        // Get a location of some free memory and store it in tempBytes as
        // Solidity does for memory variables.
            tempBytes := mload(0x40)

        // Store the length of the first bytes array at the beginning of
        // the memory for tempBytes.
            let length := mload(_preBytes)
            mstore(tempBytes, length)

        // Maintain a memory counter for the current write location in the
        // temp bytes array by adding the 32 bytes for the array length to
        // the starting location.
            let mc := add(tempBytes, 0x20)
        // Stop copying when the memory counter reaches the length of the
        // first bytes array.
            let end := add(mc, length)

            for {
            // Initialize a copy counter to the start of the _preBytes data,
            // 32 bytes into its memory.
                let cc := add(_preBytes, 0x20)
            } lt(mc, end) {
            // Increase both counters by 32 bytes each iteration.
                mc := add(mc, 0x20)
                cc := add(cc, 0x20)
            } {
            // Write the _preBytes data into the tempBytes memory 32 bytes
            // at a time.
                mstore(mc, mload(cc))
            }

        // Add the length of _postBytes to the current length of tempBytes
        // and store it as the new length in the first 32 bytes of the
        // tempBytes memory.
            length := mload(_postBytes)
            mstore(tempBytes, add(length, mload(tempBytes)))

        // Move the memory counter back from a multiple of 0x20 to the
        // actual end of the _preBytes data.
            mc := end
        // Stop copying when the memory counter reaches the new combined
        // length of the arrays.
            end := add(mc, length)

            for {
                let cc := add(_postBytes, 0x20)
            } lt(mc, end) {
                mc := add(mc, 0x20)
                cc := add(cc, 0x20)
            } {
                mstore(mc, mload(cc))
            }

        // Update the free-memory pointer by padding our last write location
        // to 32 bytes: add 31 bytes to the end of tempBytes to move to the
        // next 32 byte block, then round down to the nearest multiple of
        // 32. If the sum of the length of the two arrays is zero then add
        // one before rounding down to leave a blank 32 bytes (the length block with 0).
            mstore(0x40, and(
                add(add(end, iszero(add(length, mload(_preBytes)))), 31),
                not(31) // Round down to the nearest 32 bytes.
            ))
        }

        return tempBytes;
    }

    function concatStorage(bytes storage _preBytes, bytes memory _postBytes) internal {
        assembly {
        // Read the first 32 bytes of _preBytes storage, which is the length
        // of the array. (We don't need to use the offset into the slot
        // because arrays use the entire slot.)
            let fslot := sload(_preBytes.slot)
        // Arrays of 31 bytes or less have an even value in their slot,
        // while longer arrays have an odd value. The actual length is
        // the slot divided by two for odd values, and the lowest order
        // byte divided by two for even values.
        // If the slot is even, bitwise and the slot with 255 and divide by
        // two to get the length. If the slot is odd, bitwise and the slot
        // with -1 and divide by two.
            let slength := div(and(fslot, sub(mul(0x100, iszero(and(fslot, 1))), 1)), 2)
            let mlength := mload(_postBytes)
            let newlength := add(slength, mlength)
        // slength can contain both the length and contents of the array
        // if length < 32 bytes so let's prepare for that
        // v. http://solidity.readthedocs.io/en/latest/miscellaneous.html#layout-of-state-variables-in-storage
            switch add(lt(slength, 32), lt(newlength, 32))
            case 2 {
            // Since the new array still fits in the slot, we just need to
            // update the contents of the slot.
            // uint256(bytes_storage) = uint256(bytes_storage) + uint256(bytes_memory) + new_length
                sstore(
                    _preBytes.slot,
                // all the modifications to the slot are inside this
                // next block
                    add(
                    // we can just add to the slot contents because the
                    // bytes we want to change are the LSBs
                        fslot,
                        add(
                            mul(
                                div(
                                // load the bytes from memory
                                    mload(add(_postBytes, 0x20)),
                                // zero all bytes to the right
                                    exp(0x100, sub(32, mlength))
                                ),
                            // and now shift left the number of bytes to
                            // leave space for the length in the slot
                                exp(0x100, sub(32, newlength))
                            ),
                        // increase length by the double of the memory
                        // bytes length
                            mul(mlength, 2)
                        )
                    )
                )
            }
            case 1 {
            // The stored value fits in the slot, but the combined value
            // will exceed it.
            // get the keccak hash to get the contents of the array
                mstore(0x0, _preBytes.slot)
                let sc := add(keccak256(0x0, 0x20), div(slength, 32))

            // save new length
                sstore(_preBytes.slot, add(mul(newlength, 2), 1))

            // The contents of the _postBytes array start 32 bytes into
            // the structure. Our first read should obtain the `submod`
            // bytes that can fit into the unused space in the last word
            // of the stored array. To get this, we read 32 bytes starting
            // from `submod`, so the data we read overlaps with the array
            // contents by `submod` bytes. Masking the lowest-order
            // `submod` bytes allows us to add that value directly to the
            // stored value.

                let submod := sub(32, slength)
                let mc := add(_postBytes, submod)
                let end := add(_postBytes, mlength)
                let mask := sub(exp(0x100, submod), 1)

                sstore(
                    sc,
                    add(
                        and(
                            fslot,
                            0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff00
                        ),
                        and(mload(mc), mask)
                    )
                )

                for {
                    mc := add(mc, 0x20)
                    sc := add(sc, 1)
                } lt(mc, end) {
                    sc := add(sc, 1)
                    mc := add(mc, 0x20)
                } {
                    sstore(sc, mload(mc))
                }

                mask := exp(0x100, sub(mc, end))

                sstore(sc, mul(div(mload(mc), mask), mask))
            }
            default {
            // get the keccak hash to get the contents of the array
                mstore(0x0, _preBytes.slot)
            // Start copying to the last used word of the stored array.
                let sc := add(keccak256(0x0, 0x20), div(slength, 32))

            // save new length
                sstore(_preBytes.slot, add(mul(newlength, 2), 1))

            // Copy over the first `submod` bytes of the new data as in
            // case 1 above.
                let slengthmod := mod(slength, 32)
                let mlengthmod := mod(mlength, 32)
                let submod := sub(32, slengthmod)
                let mc := add(_postBytes, submod)
                let end := add(_postBytes, mlength)
                let mask := sub(exp(0x100, submod), 1)

                sstore(sc, add(sload(sc), and(mload(mc), mask)))

                for {
                    sc := add(sc, 1)
                    mc := add(mc, 0x20)
                } lt(mc, end) {
                    sc := add(sc, 1)
                    mc := add(mc, 0x20)
                } {
                    sstore(sc, mload(mc))
                }

                mask := exp(0x100, sub(mc, end))

                sstore(sc, mul(div(mload(mc), mask), mask))
            }
        }
    }

    function slice(
        bytes memory _bytes,
        uint256 _start,
        uint256 _length
    )
    internal
    pure
    returns (bytes memory)
    {
        require(_length + 31 >= _length, "slice_overflow");
        require(_bytes.length >= _start + _length, "slice_outOfBounds");

        bytes memory tempBytes;

        assembly {
            switch iszero(_length)
            case 0 {
            // Get a location of some free memory and store it in tempBytes as
            // Solidity does for memory variables.
                tempBytes := mload(0x40)

            // The first word of the slice result is potentially a partial
            // word read from the original array. To read it, we calculate
            // the length of that partial word and start copying that many
            // bytes into the array. The first word we copy will start with
            // data we don't care about, but the last `lengthmod` bytes will
            // land at the beginning of the contents of the new array. When
            // we're done copying, we overwrite the full first word with
            // the actual length of the slice.
                let lengthmod := and(_length, 31)

            // The multiplication in the next line is necessary
            // because when slicing multiples of 32 bytes (lengthmod == 0)
            // the following copy loop was copying the origin's length
            // and then ending prematurely not copying everything it should.
                let mc := add(add(tempBytes, lengthmod), mul(0x20, iszero(lengthmod)))
                let end := add(mc, _length)

                for {
                // The multiplication in the next line has the same exact purpose
                // as the one above.
                    let cc := add(add(add(_bytes, lengthmod), mul(0x20, iszero(lengthmod))), _start)
                } lt(mc, end) {
                    mc := add(mc, 0x20)
                    cc := add(cc, 0x20)
                } {
                    mstore(mc, mload(cc))
                }

                mstore(tempBytes, _length)

            //update free-memory pointer
            //allocating the array padded to 32 bytes like the compiler does now
                mstore(0x40, and(add(mc, 31), not(31)))
            }
            //if we want a zero-length slice let's just return a zero-length array
            default {
                tempBytes := mload(0x40)
            //zero out the 32 bytes slice we are about to return
            //we need to do it because Solidity does not garbage collect
                mstore(tempBytes, 0)

                mstore(0x40, add(tempBytes, 0x20))
            }
        }

        return tempBytes;
    }

    function toAddress(bytes memory _bytes, uint256 _start) internal pure returns (address) {
        require(_bytes.length >= _start + 20, "toAddress_outOfBounds");
        address tempAddress;

        assembly {
            tempAddress := div(mload(add(add(_bytes, 0x20), _start)), 0x1000000000000000000000000)
        }

        return tempAddress;
    }

    function toUint8(bytes memory _bytes, uint256 _start) internal pure returns (uint8) {
        require(_bytes.length >= _start + 1 , "toUint8_outOfBounds");
        uint8 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0x1), _start))
        }

        return tempUint;
    }

    function toUint16(bytes memory _bytes, uint256 _start) internal pure returns (uint16) {
        require(_bytes.length >= _start + 2, "toUint16_outOfBounds");
        uint16 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0x2), _start))
        }

        return tempUint;
    }

    function toUint32(bytes memory _bytes, uint256 _start) internal pure returns (uint32) {
        require(_bytes.length >= _start + 4, "toUint32_outOfBounds");
        uint32 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0x4), _start))
        }

        return tempUint;
    }

    function toUint64(bytes memory _bytes, uint256 _start) internal pure returns (uint64) {
        require(_bytes.length >= _start + 8, "toUint64_outOfBounds");
        uint64 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0x8), _start))
        }

        return tempUint;
    }

    function toUint96(bytes memory _bytes, uint256 _start) internal pure returns (uint96) {
        require(_bytes.length >= _start + 12, "toUint96_outOfBounds");
        uint96 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0xc), _start))
        }

        return tempUint;
    }

    function toUint128(bytes memory _bytes, uint256 _start) internal pure returns (uint128) {
        require(_bytes.length >= _start + 16, "toUint128_outOfBounds");
        uint128 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0x10), _start))
        }

        return tempUint;
    }

    function toUint256(bytes memory _bytes, uint256 _start) internal pure returns (uint256) {
        require(_bytes.length >= _start + 32, "toUint256_outOfBounds");
        uint256 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0x20), _start))
        }

        return tempUint;
    }

    function toBytes32(bytes memory _bytes, uint256 _start) internal pure returns (bytes32) {
        require(_bytes.length >= _start + 32, "toBytes32_outOfBounds");
        bytes32 tempBytes32;

        assembly {
            tempBytes32 := mload(add(add(_bytes, 0x20), _start))
        }

        return tempBytes32;
    }

    function equal(bytes memory _preBytes, bytes memory _postBytes) internal pure returns (bool) {
        bool success = true;

        assembly {
            let length := mload(_preBytes)

        // if lengths don't match the arrays are not equal
            switch eq(length, mload(_postBytes))
            case 1 {
            // cb is a circuit breaker in the for loop since there's
            //  no said feature for inline assembly loops
            // cb = 1 - don't breaker
            // cb = 0 - break
                let cb := 1

                let mc := add(_preBytes, 0x20)
                let end := add(mc, length)

                for {
                    let cc := add(_postBytes, 0x20)
                // the next line is the loop condition:
                // while(uint256(mc < end) + cb == 2)
                } eq(add(lt(mc, end), cb), 2) {
                    mc := add(mc, 0x20)
                    cc := add(cc, 0x20)
                } {
                // if any of these checks fails then arrays are not equal
                    if iszero(eq(mload(mc), mload(cc))) {
                    // unsuccess:
                        success := 0
                        cb := 0
                    }
                }
            }
            default {
            // unsuccess:
                success := 0
            }
        }

        return success;
    }

    function equal_nonAligned(bytes memory _preBytes, bytes memory _postBytes) internal pure returns (bool) {
        bool success = true;

        assembly {
            let length := mload(_preBytes)

        // if lengths don't match the arrays are not equal
            switch eq(length, mload(_postBytes))
            case 1 {
            // cb is a circuit breaker in the for loop since there's
            //  no said feature for inline assembly loops
            // cb = 1 - don't breaker
            // cb = 0 - break
                let cb := 1

                let endMinusWord := add(_preBytes, length)
                let mc := add(_preBytes, 0x20)
                let cc := add(_postBytes, 0x20)

                for {
                // the next line is the loop condition:
                // while(uint256(mc < endWord) + cb == 2)
                } eq(add(lt(mc, endMinusWord), cb), 2) {
                    mc := add(mc, 0x20)
                    cc := add(cc, 0x20)
                } {
                // if any of these checks fails then arrays are not equal
                    if iszero(eq(mload(mc), mload(cc))) {
                    // unsuccess:
                        success := 0
                        cb := 0
                    }
                }

            // Only if still successful
            // For <1 word tail bytes
                if gt(success, 0) {
                // Get the remainder of length/32
                // length % 32 = AND(length, 32 - 1)
                    let numTailBytes := and(length, 0x1f)
                    let mcRem := mload(mc)
                    let ccRem := mload(cc)
                    for {
                        let i := 0
                    // the next line is the loop condition:
                    // while(uint256(i < numTailBytes) + cb == 2)
                    } eq(add(lt(i, numTailBytes), cb), 2) {
                        i := add(i, 1)
                    } {
                        if iszero(eq(byte(i, mcRem), byte(i, ccRem))) {
                        // unsuccess:
                            success := 0
                            cb := 0
                        }
                    }
                }
            }
            default {
            // unsuccess:
                success := 0
            }
        }

        return success;
    }

    function equalStorage(
        bytes storage _preBytes,
        bytes memory _postBytes
    )
    internal
    view
    returns (bool)
    {
        bool success = true;

        assembly {
        // we know _preBytes_offset is 0
            let fslot := sload(_preBytes.slot)
        // Decode the length of the stored array like in concatStorage().
            let slength := div(and(fslot, sub(mul(0x100, iszero(and(fslot, 1))), 1)), 2)
            let mlength := mload(_postBytes)

        // if lengths don't match the arrays are not equal
            switch eq(slength, mlength)
            case 1 {
            // slength can contain both the length and contents of the array
            // if length < 32 bytes so let's prepare for that
            // v. http://solidity.readthedocs.io/en/latest/miscellaneous.html#layout-of-state-variables-in-storage
                if iszero(iszero(slength)) {
                    switch lt(slength, 32)
                    case 1 {
                    // blank the last byte which is the length
                        fslot := mul(div(fslot, 0x100), 0x100)

                        if iszero(eq(fslot, mload(add(_postBytes, 0x20)))) {
                        // unsuccess:
                            success := 0
                        }
                    }
                    default {
                    // cb is a circuit breaker in the for loop since there's
                    //  no said feature for inline assembly loops
                    // cb = 1 - don't breaker
                    // cb = 0 - break
                        let cb := 1

                    // get the keccak hash to get the contents of the array
                        mstore(0x0, _preBytes.slot)
                        let sc := keccak256(0x0, 0x20)

                        let mc := add(_postBytes, 0x20)
                        let end := add(mc, mlength)

                    // the next line is the loop condition:
                    // while(uint256(mc < end) + cb == 2)
                        for {} eq(add(lt(mc, end), cb), 2) {
                            sc := add(sc, 1)
                            mc := add(mc, 0x20)
                        } {
                            if iszero(eq(sload(sc), mload(mc))) {
                            // unsuccess:
                                success := 0
                                cb := 0
                            }
                        }
                    }
                }
            }
            default {
            // unsuccess:
                success := 0
            }
        }

        return success;
    }
}