pragma solidity 0.4.26;

library SafeMath {

  /**
  * @dev Multiplies two numbers, throws on overflow.
  */
  function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
    if (a == 0) {
      return 0;
    }
    c = a * b;
    assert(c / a == b);
    return c;
  }

  /**
  * @dev Integer division of two numbers, truncating the quotient.
  */
  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    // assert(b > 0); // Solidity automatically throws when dividing by 0
    // uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
    return a / b;
  }

  /**
  * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  /**
  * @dev Adds two numbers, throws on overflow.
  */
  function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
    c = a + b;
    assert(c >= a);
    return c;
  }
}

contract Ownable {
  address public owner;


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


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  constructor() public {
    owner = msg.sender;
  }

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

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipRenounced(owner);
    owner = address(0);
  }
}

contract ERC20Basic {
  function totalSupply() public view returns (uint256);
  function balanceOf(address who) public view returns (uint256);
  function transfer(address to, uint256 value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}

contract ERC20 is ERC20Basic {
  function allowance(address owner, address spender)
    public view returns (uint256);

  function transferFrom(address from, address to, uint256 value)
    public returns (bool);

  function approve(address spender, uint256 value) public returns (bool);
  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

library ArrayUtils {

    /**
     * Replace bytes in an array with bytes in another array, guarded by a bitmask
     * Efficiency of this function is a bit unpredictable because of the EVM's word-specific model (arrays under 32 bytes will be slower)
     *
     * @dev Mask must be the size of the byte array. A nonzero byte means the byte array can be changed.
     * @param array The original array
     * @param desired The target array
     * @param mask The mask specifying which bits can be changed
     * @return The updated byte array (the parameter will be modified inplace)
     */
    function guardedArrayReplace(bytes memory array, bytes memory desired, bytes memory mask)
        internal
        pure
    {
        require(array.length == desired.length);
        require(array.length == mask.length);

        uint words = array.length / 0x20;
        uint index = words * 0x20;
        assert(index / 0x20 == words);
        uint i;

        for (i = 0; i < words; i++) {
            /* Conceptually: array[i] = (!mask[i] && array[i]) || (mask[i] && desired[i]), bitwise in word chunks. */
            assembly {
                let commonIndex := mul(0x20, add(1, i))
                let maskValue := mload(add(mask, commonIndex))
                mstore(add(array, commonIndex), or(and(not(maskValue), mload(add(array, commonIndex))), and(maskValue, mload(add(desired, commonIndex)))))
            }
        }

        /* Deal with the last section of the byte array. */
        if (words > 0) {
            /* This overlaps with bytes already set but is still more efficient than iterating through each of the remaining bytes individually. */
            i = words;
            assembly {
                let commonIndex := mul(0x20, add(1, i))
                let maskValue := mload(add(mask, commonIndex))
                mstore(add(array, commonIndex), or(and(not(maskValue), mload(add(array, commonIndex))), and(maskValue, mload(add(desired, commonIndex)))))
            }
        } else {
            /* If the byte array is shorter than a word, we must unfortunately do the whole thing bytewise.
               (bounds checks could still probably be optimized away in assembly, but this is a rare case) */
            for (i = index; i < array.length; i++) {
                array[i] = ((mask[i] ^ 0xff) & array[i]) | (mask[i] & desired[i]);
            }
        }
    }

    /**
     * Test if two arrays are equal
     * @param a First array
     * @param b Second array
     * @return Whether or not all bytes in the arrays are equal
     */
    function arrayEq(bytes memory a, bytes memory b)
        internal
        pure
        returns (bool)
    {
        return keccak256(a) == keccak256(b);
    }

    /**
     * Unsafe write byte array into a memory location
     *
     * @param index Memory location
     * @param source Byte array to write
     * @return End memory index
     */
    function unsafeWriteBytes(uint index, bytes source)
        internal
        pure
        returns (uint)
    {
        if (source.length > 0) {
            assembly {
                let length := mload(source)
                let end := add(source, add(0x20, length))
                let arrIndex := add(source, 0x20)
                let tempIndex := index
                for { } eq(lt(arrIndex, end), 1) {
                    arrIndex := add(arrIndex, 0x20)
                    tempIndex := add(tempIndex, 0x20)
                } {
                    mstore(tempIndex, mload(arrIndex))
                }
                index := add(index, length)
            }
        }
        return index;
    }

    /**
     * Unsafe write address into a memory location
     *
     * @param index Memory location
     * @param source Address to write
     * @return End memory index
     */
    function unsafeWriteAddress(uint index, address source)
        internal
        pure
        returns (uint)
    {
        uint conv = uint(source) << 0x60;
        assembly {
            mstore(index, conv)
            index := add(index, 0x14)
        }
        return index;
    }

    /**
     * Unsafe write address into a memory location using entire word
     *
     * @param index Memory location
     * @param source uint to write
     * @return End memory index
     */
    function unsafeWriteAddressWord(uint index, address source)
        internal
        pure
        returns (uint)
    {
        assembly {
            mstore(index, source)
            index := add(index, 0x20)
        }
        return index;
    }

    /**
     * Unsafe write uint into a memory location
     *
     * @param index Memory location
     * @param source uint to write
     * @return End memory index
     */
    function unsafeWriteUint(uint index, uint source)
        internal
        pure
        returns (uint)
    {
        assembly {
            mstore(index, source)
            index := add(index, 0x20)
        }
        return index;
    }

    /**
     * Unsafe write uint8 into a memory location
     *
     * @param index Memory location
     * @param source uint8 to write
     * @return End memory index
     */
    function unsafeWriteUint8(uint index, uint8 source)
        internal
        pure
        returns (uint)
    {
        assembly {
            mstore8(index, source)
            index := add(index, 0x1)
        }
        return index;
    }

    /**
     * Unsafe write uint8 into a memory location using entire word
     *
     * @param index Memory location
     * @param source uint to write
     * @return End memory index
     */
    function unsafeWriteUint8Word(uint index, uint8 source)
        internal
        pure
        returns (uint)
    {
        assembly {
            mstore(index, source)
            index := add(index, 0x20)
        }
        return index;
    }

    /**
     * Unsafe write bytes32 into a memory location using entire word
     *
     * @param index Memory location
     * @param source uint to write
     * @return End memory index
     */
    function unsafeWriteBytes32(uint index, bytes32 source)
        internal
        pure
        returns (uint)
    {
        assembly {
            mstore(index, source)
            index := add(index, 0x20)
        }
        return index;
    }
}

contract ReentrancyGuarded {

    bool reentrancyLock = false;

    /* Prevent a contract function from being reentrant-called. */
    modifier reentrancyGuard {
        if (reentrancyLock) {
            revert();
        }
        reentrancyLock = true;
        _;
        reentrancyLock = false;
    }

}

contract TokenRecipient {
    event ReceivedEther(address indexed sender, uint amount);
    event ReceivedTokens(address indexed from, uint256 value, address indexed token, bytes extraData);

    /**
     * @dev Receive tokens and generate a log event
     * @param from Address from which to transfer tokens
     * @param value Amount of tokens to transfer
     * @param token Address of token
     * @param extraData Additional data to log
     */
    function receiveApproval(address from, uint256 value, address token, bytes extraData) public {
        ERC20 t = ERC20(token);
        require(t.transferFrom(from, this, value));
        emit ReceivedTokens(from, value, token, extraData);
    }

    /**
     * @dev Receive Ether and generate a log event
     */
    function () payable public {
        emit ReceivedEther(msg.sender, msg.value);
    }
}

contract ExchangeCore is ReentrancyGuarded, Ownable {
    string public constant name = "Wyvern Exchange Contract";
    string public constant version = "2.3";

    // NOTE: these hashes are derived and verified in the constructor.
    bytes32 private constant _EIP_712_DOMAIN_TYPEHASH = 0x8b73c3c69bb8fe3d512ecc4cf759cc79239f7b179b0ffacaa9a75d522b39400f;
    bytes32 private constant _NAME_HASH = 0x9a2ed463836165738cfa54208ff6e7847fd08cbaac309aac057086cb0a144d13;
    bytes32 private constant _VERSION_HASH = 0xe2fd538c762ee69cab09ccd70e2438075b7004dd87577dc3937e9fcc8174bb64;
    bytes32 private constant _ORDER_TYPEHASH = 0xdba08a88a748f356e8faf8578488343eab21b1741728779c9dcfdc782bc800f8;

    bytes4 private constant _EIP_1271_MAGIC_VALUE = 0x1626ba7e;

    //    // NOTE: chainId opcode is not supported in solidiy 0.4.x; here we hardcode as 1.
    // In order to protect against orders that are replayable across forked chains,
    // either the solidity version needs to be bumped up or it needs to be retrieved
    // from another contract.
    uint256 private constant _CHAIN_ID = 1;

    // Note: the domain separator is derived and verified in the constructor. */
    bytes32 public constant DOMAIN_SEPARATOR = 0x72982d92449bfb3d338412ce4738761aff47fb975ceb17a1bc3712ec716a5a68;

    /* The token used to pay exchange fees. */
    ERC20 public exchangeToken;

    /* User registry. */
    ProxyRegistry public registry;

    /* Token transfer proxy. */
    TokenTransferProxy public tokenTransferProxy;

    /* Cancelled / finalized orders, by hash. */
    mapping(bytes32 => bool) public cancelledOrFinalized;

    /* Orders verified by on-chain approval (alternative to ECDSA signatures so that smart contracts can place orders directly). */
    /* Note that the maker's nonce at the time of approval **plus one** is stored in the mapping. */
    mapping(bytes32 => uint256) private _approvedOrdersByNonce;

    /* Track per-maker nonces that can be incremented by the maker to cancel orders in bulk. */
    // The current nonce for the maker represents the only valid nonce that can be signed by the maker
    // If a signature was signed with a nonce that's different from the one stored in nonces, it
    // will fail validation.
    mapping(address => uint256) public nonces;

    /* For split fee orders, minimum required protocol maker fee, in basis points. Paid to owner (who can change it). */
    uint public minimumMakerProtocolFee = 0;

    /* For split fee orders, minimum required protocol taker fee, in basis points. Paid to owner (who can change it). */
    uint public minimumTakerProtocolFee = 0;

    /* Recipient of protocol fees. */
    address public protocolFeeRecipient;

    /* Fee method: protocol fee or split fee. */
    enum FeeMethod { ProtocolFee, SplitFee }

    /* Inverse basis point. */
    uint public constant INVERSE_BASIS_POINT = 10000;

    /* An ECDSA signature. */
    struct Sig {
        /* v parameter */
        uint8 v;
        /* r parameter */
        bytes32 r;
        /* s parameter */
        bytes32 s;
    }

    /* An order on the exchange. */
    struct Order {
        /* Exchange address, intended as a versioning mechanism. */
        address exchange;
        /* Order maker address. */
        address maker;
        /* Order taker address, if specified. */
        address taker;
        /* Maker relayer fee of the order, unused for taker order. */
        uint makerRelayerFee;
        /* Taker relayer fee of the order, or maximum taker fee for a taker order. */
        uint takerRelayerFee;
        /* Maker protocol fee of the order, unused for taker order. */
        uint makerProtocolFee;
        /* Taker protocol fee of the order, or maximum taker fee for a taker order. */
        uint takerProtocolFee;
        /* Order fee recipient or zero address for taker order. */
        address feeRecipient;
        /* Fee method (protocol token or split fee). */
        FeeMethod feeMethod;
        /* Side (buy/sell). */
        SaleKindInterface.Side side;
        /* Kind of sale. */
        SaleKindInterface.SaleKind saleKind;
        /* Target. */
        address target;
        /* HowToCall. */
        AuthenticatedProxy.HowToCall howToCall;
        /* Calldata. */
        bytes calldata;
        /* Calldata replacement pattern, or an empty byte array for no replacement. */
        bytes replacementPattern;
        /* Static call target, zero-address for no static call. */
        address staticTarget;
        /* Static call extra data. */
        bytes staticExtradata;
        /* Token used to pay for the order, or the zero-address as a sentinel value for Ether. */
        address paymentToken;
        /* Base price of the order (in paymentTokens). */
        uint basePrice;
        /* Auction extra parameter - minimum bid increment for English auctions, starting/ending price difference. */
        uint extra;
        /* Listing timestamp. */
        uint listingTime;
        /* Expiration timestamp - 0 for no expiry. */
        uint expirationTime;
        /* Order salt, used to prevent duplicate hashes. */
        uint salt;
        /* NOTE: uint nonce is an additional component of the order but is read from storage */
    }

    event OrderApprovedPartOne    (bytes32 indexed hash, address exchange, address indexed maker, address taker, uint makerRelayerFee, uint takerRelayerFee, uint makerProtocolFee, uint takerProtocolFee, address indexed feeRecipient, FeeMethod feeMethod, SaleKindInterface.Side side, SaleKindInterface.SaleKind saleKind, address target);
    event OrderApprovedPartTwo    (bytes32 indexed hash, AuthenticatedProxy.HowToCall howToCall, bytes calldata, bytes replacementPattern, address staticTarget, bytes staticExtradata, address paymentToken, uint basePrice, uint extra, uint listingTime, uint expirationTime, uint salt, bool orderbookInclusionDesired);
    event OrderCancelled          (bytes32 indexed hash);
    event OrdersMatched           (bytes32 buyHash, bytes32 sellHash, address indexed maker, address indexed taker, uint price, bytes32 indexed metadata);
    event NonceIncremented        (address indexed maker, uint newNonce);

    constructor () public {
        require(keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)") == _EIP_712_DOMAIN_TYPEHASH);
        require(keccak256(bytes(name)) == _NAME_HASH);
        require(keccak256(bytes(version)) == _VERSION_HASH);
        require(keccak256("Order(address exchange,address maker,address taker,uint256 makerRelayerFee,uint256 takerRelayerFee,uint256 makerProtocolFee,uint256 takerProtocolFee,address feeRecipient,uint8 feeMethod,uint8 side,uint8 saleKind,address target,uint8 howToCall,bytes calldata,bytes replacementPattern,address staticTarget,bytes staticExtradata,address paymentToken,uint256 basePrice,uint256 extra,uint256 listingTime,uint256 expirationTime,uint256 salt,uint256 nonce)") == _ORDER_TYPEHASH);
        require(DOMAIN_SEPARATOR == _deriveDomainSeparator());
    }

    /**
     * @dev Derive the domain separator for EIP-712 signatures.
     * @return The domain separator.
     */
    function _deriveDomainSeparator() private view returns (bytes32) {
        return keccak256(
            abi.encode(
                _EIP_712_DOMAIN_TYPEHASH, // keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)")
                _NAME_HASH, // keccak256("Wyvern Exchange Contract")
                _VERSION_HASH, // keccak256(bytes("2.3"))
                _CHAIN_ID, // NOTE: this is fixed, need to use solidity 0.5+ or make external call to support!
                address(this)
            )
        );
    }

    /**
     * Increment a particular maker's nonce, thereby invalidating all orders that were not signed
     * with the original nonce.
     */
    function incrementNonce() external {
        uint newNonce = ++nonces[msg.sender];
        emit NonceIncremented(msg.sender, newNonce);
    }

    /**
     * @dev Change the minimum maker fee paid to the protocol (owner only)
     * @param newMinimumMakerProtocolFee New fee to set in basis points
     */
    function changeMinimumMakerProtocolFee(uint newMinimumMakerProtocolFee)
        public
        onlyOwner
    {
        minimumMakerProtocolFee = newMinimumMakerProtocolFee;
    }

    /**
     * @dev Change the minimum taker fee paid to the protocol (owner only)
     * @param newMinimumTakerProtocolFee New fee to set in basis points
     */
    function changeMinimumTakerProtocolFee(uint newMinimumTakerProtocolFee)
        public
        onlyOwner
    {
        minimumTakerProtocolFee = newMinimumTakerProtocolFee;
    }

    /**
     * @dev Change the protocol fee recipient (owner only)
     * @param newProtocolFeeRecipient New protocol fee recipient address
     */
    function changeProtocolFeeRecipient(address newProtocolFeeRecipient)
        public
        onlyOwner
    {
        protocolFeeRecipient = newProtocolFeeRecipient;
    }

    /**
     * @dev Transfer tokens
     * @param token Token to transfer
     * @param from Address to charge fees
     * @param to Address to receive fees
     * @param amount Amount of protocol tokens to charge
     */
    function transferTokens(address token, address from, address to, uint amount)
        internal
    {
        if (amount > 0) {
            require(tokenTransferProxy.transferFrom(token, from, to, amount));
        }
    }

    /**
     * @dev Charge a fee in protocol tokens
     * @param from Address to charge fees
     * @param to Address to receive fees
     * @param amount Amount of protocol tokens to charge
     */
    function chargeProtocolFee(address from, address to, uint amount)
        internal
    {
        transferTokens(exchangeToken, from, to, amount);
    }

    /**
     * @dev Execute a STATICCALL (introduced with Ethereum Metropolis, non-state-modifying external call)
     * @param target Contract to call
     * @param calldata Calldata (appended to extradata)
     * @param extradata Base data for STATICCALL (probably function selector and argument encoding)
     * @return The result of the call (success or failure)
     */
    function staticCall(address target, bytes memory calldata, bytes memory extradata)
        public
        view
        returns (bool result)
    {
        bytes memory combined = new bytes(calldata.length + extradata.length);
        uint index;
        assembly {
            index := add(combined, 0x20)
        }
        index = ArrayUtils.unsafeWriteBytes(index, extradata);
        ArrayUtils.unsafeWriteBytes(index, calldata);
        assembly {
            result := staticcall(gas, target, add(combined, 0x20), mload(combined), mload(0x40), 0)
        }
        return result;
    }

    /**
     * @dev Hash an order, returning the canonical EIP-712 order hash without the domain separator
     * @param order Order to hash
     * @param nonce maker nonce to hash
     * @return Hash of order
     */
    function hashOrder(Order memory order, uint nonce)
        internal
        pure
        returns (bytes32 hash)
    {
        /* Unfortunately abi.encodePacked doesn't work here, stack size constraints. */
        uint size = 800;
        bytes memory array = new bytes(size);
        uint index;
        assembly {
            index := add(array, 0x20)
        }
        index = ArrayUtils.unsafeWriteBytes32(index, _ORDER_TYPEHASH);
        index = ArrayUtils.unsafeWriteAddressWord(index, order.exchange);
        index = ArrayUtils.unsafeWriteAddressWord(index, order.maker);
        index = ArrayUtils.unsafeWriteAddressWord(index, order.taker);
        index = ArrayUtils.unsafeWriteUint(index, order.makerRelayerFee);
        index = ArrayUtils.unsafeWriteUint(index, order.takerRelayerFee);
        index = ArrayUtils.unsafeWriteUint(index, order.makerProtocolFee);
        index = ArrayUtils.unsafeWriteUint(index, order.takerProtocolFee);
        index = ArrayUtils.unsafeWriteAddressWord(index, order.feeRecipient);
        index = ArrayUtils.unsafeWriteUint8Word(index, uint8(order.feeMethod));
        index = ArrayUtils.unsafeWriteUint8Word(index, uint8(order.side));
        index = ArrayUtils.unsafeWriteUint8Word(index, uint8(order.saleKind));
        index = ArrayUtils.unsafeWriteAddressWord(index, order.target);
        index = ArrayUtils.unsafeWriteUint8Word(index, uint8(order.howToCall));
        index = ArrayUtils.unsafeWriteBytes32(index, keccak256(order.calldata));
        index = ArrayUtils.unsafeWriteBytes32(index, keccak256(order.replacementPattern));
        index = ArrayUtils.unsafeWriteAddressWord(index, order.staticTarget);
        index = ArrayUtils.unsafeWriteBytes32(index, keccak256(order.staticExtradata));
        index = ArrayUtils.unsafeWriteAddressWord(index, order.paymentToken);
        index = ArrayUtils.unsafeWriteUint(index, order.basePrice);
        index = ArrayUtils.unsafeWriteUint(index, order.extra);
        index = ArrayUtils.unsafeWriteUint(index, order.listingTime);
        index = ArrayUtils.unsafeWriteUint(index, order.expirationTime);
        index = ArrayUtils.unsafeWriteUint(index, order.salt);
        index = ArrayUtils.unsafeWriteUint(index, nonce);
        assembly {
            hash := keccak256(add(array, 0x20), size)
        }
        return hash;
    }

    /**
     * @dev Hash an order, returning the hash that a client must sign via EIP-712 including the message prefix
     * @param order Order to hash
     * @param nonce Nonce to hash
     * @return Hash of message prefix and order hash per Ethereum format
     */
    function hashToSign(Order memory order, uint nonce)
        internal
        pure
        returns (bytes32)
    {
        return keccak256(
            abi.encodePacked("\x19\x01", DOMAIN_SEPARATOR, hashOrder(order, nonce))
        );
    }

    /**
     * @dev Assert an order is valid and return its hash
     * @param order Order to validate
     * @param nonce Nonce to validate
     * @param sig ECDSA signature
     */
    function requireValidOrder(Order memory order, Sig memory sig, uint nonce)
        internal
        view
        returns (bytes32)
    {
        bytes32 hash = hashToSign(order, nonce);
        require(validateOrder(hash, order, sig));
        return hash;
    }

    /**
     * @dev Validate order parameters (does *not* check signature validity)
     * @param order Order to validate
     */
    function validateOrderParameters(Order memory order)
        internal
        view
        returns (bool)
    {
        /* Order must be targeted at this protocol version (this Exchange contract). */
        if (order.exchange != address(this)) {
            return false;
        }

        /* Order must have a maker. */
        if (order.maker == address(0)) {
            return false;
        }

        /* Order must possess valid sale kind parameter combination. */
        if (!SaleKindInterface.validateParameters(order.saleKind, order.expirationTime)) {
            return false;
        }

        /* If using the split fee method, order must have sufficient protocol fees. */
        if (order.feeMethod == FeeMethod.SplitFee && (order.makerProtocolFee < minimumMakerProtocolFee || order.takerProtocolFee < minimumTakerProtocolFee)) {
            return false;
        }

        return true;
    }

    /**
     * @dev Validate a provided previously approved / signed order, hash, and signature.
     * @param hash Order hash (already calculated, passed to avoid recalculation)
     * @param order Order to validate
     * @param sig ECDSA signature
     */
    function validateOrder(bytes32 hash, Order memory order, Sig memory sig)
        internal
        view
        returns (bool)
    {
        /* Not done in an if-conditional to prevent unnecessary ecrecover evaluation, which seems to happen even though it should short-circuit. */

        /* Order must have valid parameters. */
        if (!validateOrderParameters(order)) {
            return false;
        }

        /* Order must have not been canceled or already filled. */
        if (cancelledOrFinalized[hash]) {
            return false;
        }

        /* Return true if order has been previously approved with the current nonce */
        uint approvedOrderNoncePlusOne = _approvedOrdersByNonce[hash];
        if (approvedOrderNoncePlusOne != 0) {
            return approvedOrderNoncePlusOne == nonces[order.maker] + 1;
        }

        /* Prevent signature malleability and non-standard v values. */
        if (uint256(sig.s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return false;
        }
        if (sig.v != 27 && sig.v != 28) {
            return false;
        }

        /* recover via ECDSA, signed by maker (already verified as non-zero). */
        if (ecrecover(hash, sig.v, sig.r, sig.s) == order.maker) {
            return true;
        }

        /* fallback — attempt EIP-1271 isValidSignature check. */
        return _tryContractSignature(order.maker, hash, sig);
    }

    function _tryContractSignature(address orderMaker, bytes32 hash, Sig memory sig) internal view returns (bool) {
        bytes memory isValidSignatureData = abi.encodeWithSelector(
            _EIP_1271_MAGIC_VALUE,
            hash,
            abi.encodePacked(sig.r, sig.s, sig.v)
        );

        bytes4 result;

        // NOTE: solidity 0.4.x does not support STATICCALL outside of assembly
        assembly {
            let success := staticcall(           // perform a staticcall
                gas,                             // forward all available gas
                orderMaker,                      // call the order maker
                add(isValidSignatureData, 0x20), // calldata offset comes after length
                mload(isValidSignatureData),     // load calldata length
                0,                               // do not use memory for return data
                0                                // do not use memory for return data
            )

            if iszero(success) {                     // if the call fails
                returndatacopy(0, 0, returndatasize) // copy returndata buffer to memory
                revert(0, returndatasize)            // revert + pass through revert data
            }

            if eq(returndatasize, 0x20) {  // if returndata == 32 (one word)
                returndatacopy(0, 0, 0x20) // copy return data to memory in scratch space
                result := mload(0)         // load return data from memory to the stack
            }
        }

        return result == _EIP_1271_MAGIC_VALUE;
    }

    /**
     * @dev Determine if an order has been approved. Note that the order may not still
     * be valid in cases where the maker's nonce has been incremented.
     * @param hash Hash of the order
     * @return whether or not the order was approved.
     */
    function approvedOrders(bytes32 hash) public view returns (bool approved) {
        return _approvedOrdersByNonce[hash] != 0;
    }

    /**
     * @dev Approve an order and optionally mark it for orderbook inclusion. Must be called by the maker of the order
     * @param order Order to approve
     * @param orderbookInclusionDesired Whether orderbook providers should include the order in their orderbooks
     */
    function approveOrder(Order memory order, bool orderbookInclusionDesired)
        internal
    {
        /* CHECKS */

        /* Assert sender is authorized to approve order. */
        require(msg.sender == order.maker);

        /* Calculate order hash. */
        bytes32 hash = hashToSign(order, nonces[order.maker]);

        /* Assert order has not already been approved. */
        require(_approvedOrdersByNonce[hash] == 0);

        /* EFFECTS */

        /* Mark order as approved. */
        _approvedOrdersByNonce[hash] = nonces[order.maker] + 1;

        /* Log approval event. Must be split in two due to Solidity stack size limitations. */
        {
            emit OrderApprovedPartOne(hash, order.exchange, order.maker, order.taker, order.makerRelayerFee, order.takerRelayerFee, order.makerProtocolFee, order.takerProtocolFee, order.feeRecipient, order.feeMethod, order.side, order.saleKind, order.target);
        }
        {
            emit OrderApprovedPartTwo(hash, order.howToCall, order.calldata, order.replacementPattern, order.staticTarget, order.staticExtradata, order.paymentToken, order.basePrice, order.extra, order.listingTime, order.expirationTime, order.salt, orderbookInclusionDesired);
        }
    }

    /**
     * @dev Cancel an order, preventing it from being matched. Must be called by the maker of the order
     * @param order Order to cancel
     * @param nonce Nonce to cancel
     * @param sig ECDSA signature
     */
    function cancelOrder(Order memory order, Sig memory sig, uint nonce)
        internal
    {
        /* CHECKS */

        /* Calculate order hash. */
        bytes32 hash = requireValidOrder(order, sig, nonce);

        /* Assert sender is authorized to cancel order. */
        require(msg.sender == order.maker);

        /* EFFECTS */

        /* Mark order as cancelled, preventing it from being matched. */
        cancelledOrFinalized[hash] = true;

        /* Log cancel event. */
        emit OrderCancelled(hash);
    }

    /**
     * @dev Calculate the current price of an order (convenience function)
     * @param order Order to calculate the price of
     * @return The current price of the order
     */
    function calculateCurrentPrice (Order memory order)
        internal
        view
        returns (uint)
    {
        return SaleKindInterface.calculateFinalPrice(order.side, order.saleKind, order.basePrice, order.extra, order.listingTime, order.expirationTime);
    }

    /**
     * @dev Calculate the price two orders would match at, if in fact they would match (otherwise fail)
     * @param buy Buy-side order
     * @param sell Sell-side order
     * @return Match price
     */
    function calculateMatchPrice(Order memory buy, Order memory sell)
        view
        internal
        returns (uint)
    {
        /* Calculate sell price. */
        uint sellPrice = SaleKindInterface.calculateFinalPrice(sell.side, sell.saleKind, sell.basePrice, sell.extra, sell.listingTime, sell.expirationTime);

        /* Calculate buy price. */
        uint buyPrice = SaleKindInterface.calculateFinalPrice(buy.side, buy.saleKind, buy.basePrice, buy.extra, buy.listingTime, buy.expirationTime);

        /* Require price cross. */
        require(buyPrice >= sellPrice);

        /* Maker/taker priority. */
        return sell.feeRecipient != address(0) ? sellPrice : buyPrice;
    }

    /**
     * @dev Execute all ERC20 token / Ether transfers associated with an order match (fees and buyer => seller transfer)
     * @param buy Buy-side order
     * @param sell Sell-side order
     */
    function executeFundsTransfer(Order memory buy, Order memory sell)
        internal
        returns (uint)
    {
        /* Only payable in the special case of unwrapped Ether. */
        if (sell.paymentToken != address(0)) {
            require(msg.value == 0);
        }

        /* Calculate match price. */
        uint price = calculateMatchPrice(buy, sell);

        /* If paying using a token (not Ether), transfer tokens. This is done prior to fee payments to that a seller will have tokens before being charged fees. */
        if (price > 0 && sell.paymentToken != address(0)) {
            transferTokens(sell.paymentToken, buy.maker, sell.maker, price);
        }

        /* Amount that will be received by seller (for Ether). */
        uint receiveAmount = price;

        /* Amount that must be sent by buyer (for Ether). */
        uint requiredAmount = price;

        /* Determine maker/taker and charge fees accordingly. */
        if (sell.feeRecipient != address(0)) {
            /* Sell-side order is maker. */

            /* Assert taker fee is less than or equal to maximum fee specified by buyer. */
            require(sell.takerRelayerFee <= buy.takerRelayerFee);

            if (sell.feeMethod == FeeMethod.SplitFee) {
                /* Assert taker fee is less than or equal to maximum fee specified by buyer. */
                require(sell.takerProtocolFee <= buy.takerProtocolFee);

                /* Maker fees are deducted from the token amount that the maker receives. Taker fees are extra tokens that must be paid by the taker. */

                if (sell.makerRelayerFee > 0) {
                    uint makerRelayerFee = SafeMath.div(SafeMath.mul(sell.makerRelayerFee, price), INVERSE_BASIS_POINT);
                    if (sell.paymentToken == address(0)) {
                        receiveAmount = SafeMath.sub(receiveAmount, makerRelayerFee);
                        sell.feeRecipient.transfer(makerRelayerFee);
                    } else {
                        transferTokens(sell.paymentToken, sell.maker, sell.feeRecipient, makerRelayerFee);
                    }
                }

                if (sell.takerRelayerFee > 0) {
                    uint takerRelayerFee = SafeMath.div(SafeMath.mul(sell.takerRelayerFee, price), INVERSE_BASIS_POINT);
                    if (sell.paymentToken == address(0)) {
                        requiredAmount = SafeMath.add(requiredAmount, takerRelayerFee);
                        sell.feeRecipient.transfer(takerRelayerFee);
                    } else {
                        transferTokens(sell.paymentToken, buy.maker, sell.feeRecipient, takerRelayerFee);
                    }
                }

                if (sell.makerProtocolFee > 0) {
                    uint makerProtocolFee = SafeMath.div(SafeMath.mul(sell.makerProtocolFee, price), INVERSE_BASIS_POINT);
                    if (sell.paymentToken == address(0)) {
                        receiveAmount = SafeMath.sub(receiveAmount, makerProtocolFee);
                        protocolFeeRecipient.transfer(makerProtocolFee);
                    } else {
                        transferTokens(sell.paymentToken, sell.maker, protocolFeeRecipient, makerProtocolFee);
                    }
                }

                if (sell.takerProtocolFee > 0) {
                    uint takerProtocolFee = SafeMath.div(SafeMath.mul(sell.takerProtocolFee, price), INVERSE_BASIS_POINT);
                    if (sell.paymentToken == address(0)) {
                        requiredAmount = SafeMath.add(requiredAmount, takerProtocolFee);
                        protocolFeeRecipient.transfer(takerProtocolFee);
                    } else {
                        transferTokens(sell.paymentToken, buy.maker, protocolFeeRecipient, takerProtocolFee);
                    }
                }

            } else {
                /* Charge maker fee to seller. */
                chargeProtocolFee(sell.maker, sell.feeRecipient, sell.makerRelayerFee);

                /* Charge taker fee to buyer. */
                chargeProtocolFee(buy.maker, sell.feeRecipient, sell.takerRelayerFee);
            }
        } else {
            /* Buy-side order is maker. */

            /* Assert taker fee is less than or equal to maximum fee specified by seller. */
            require(buy.takerRelayerFee <= sell.takerRelayerFee);

            if (sell.feeMethod == FeeMethod.SplitFee) {
                /* The Exchange does not escrow Ether, so direct Ether can only be used to with sell-side maker / buy-side taker orders. */
                require(sell.paymentToken != address(0));

                /* Assert taker fee is less than or equal to maximum fee specified by seller. */
                require(buy.takerProtocolFee <= sell.takerProtocolFee);

                if (buy.makerRelayerFee > 0) {
                    makerRelayerFee = SafeMath.div(SafeMath.mul(buy.makerRelayerFee, price), INVERSE_BASIS_POINT);
                    transferTokens(sell.paymentToken, buy.maker, buy.feeRecipient, makerRelayerFee);
                }

                if (buy.takerRelayerFee > 0) {
                    takerRelayerFee = SafeMath.div(SafeMath.mul(buy.takerRelayerFee, price), INVERSE_BASIS_POINT);
                    transferTokens(sell.paymentToken, sell.maker, buy.feeRecipient, takerRelayerFee);
                }

                if (buy.makerProtocolFee > 0) {
                    makerProtocolFee = SafeMath.div(SafeMath.mul(buy.makerProtocolFee, price), INVERSE_BASIS_POINT);
                    transferTokens(sell.paymentToken, buy.maker, protocolFeeRecipient, makerProtocolFee);
                }

                if (buy.takerProtocolFee > 0) {
                    takerProtocolFee = SafeMath.div(SafeMath.mul(buy.takerProtocolFee, price), INVERSE_BASIS_POINT);
                    transferTokens(sell.paymentToken, sell.maker, protocolFeeRecipient, takerProtocolFee);
                }

            } else {
                /* Charge maker fee to buyer. */
                chargeProtocolFee(buy.maker, buy.feeRecipient, buy.makerRelayerFee);

                /* Charge taker fee to seller. */
                chargeProtocolFee(sell.maker, buy.feeRecipient, buy.takerRelayerFee);
            }
        }

        if (sell.paymentToken == address(0)) {
            /* Special-case Ether, order must be matched by buyer. */
            require(msg.value >= requiredAmount);
            sell.maker.transfer(receiveAmount);
            /* Allow overshoot for variable-price auctions, refund difference. */
            uint diff = SafeMath.sub(msg.value, requiredAmount);
            if (diff > 0) {
                buy.maker.transfer(diff);
            }
        }

        /* This contract should never hold Ether, however, we cannot assert this, since it is impossible to prevent anyone from sending Ether e.g. with selfdestruct. */

        return price;
    }

    /**
     * @dev Return whether or not two orders can be matched with each other by basic parameters (does not check order signatures / calldata or perform static calls)
     * @param buy Buy-side order
     * @param sell Sell-side order
     * @return Whether or not the two orders can be matched
     */
    function ordersCanMatch(Order memory buy, Order memory sell)
        internal
        view
        returns (bool)
    {
        return (
            /* Must be opposite-side. */
            (buy.side == SaleKindInterface.Side.Buy && sell.side == SaleKindInterface.Side.Sell) &&
            /* Must use same fee method. */
            (buy.feeMethod == sell.feeMethod) &&
            /* Must use same payment token. */
            (buy.paymentToken == sell.paymentToken) &&
            /* Must match maker/taker addresses. */
            (sell.taker == address(0) || sell.taker == buy.maker) &&
            (buy.taker == address(0) || buy.taker == sell.maker) &&
            /* One must be maker and the other must be taker (no bool XOR in Solidity). */
            ((sell.feeRecipient == address(0) && buy.feeRecipient != address(0)) || (sell.feeRecipient != address(0) && buy.feeRecipient == address(0))) &&
            /* Must match target. */
            (buy.target == sell.target) &&
            /* Must match howToCall. */
            (buy.howToCall == sell.howToCall) &&
            /* Buy-side order must be settleable. */
            SaleKindInterface.canSettleOrder(buy.listingTime, buy.expirationTime) &&
            /* Sell-side order must be settleable. */
            SaleKindInterface.canSettleOrder(sell.listingTime, sell.expirationTime)
        );
    }

    /**
     * @dev Atomically match two orders, ensuring validity of the match, and execute all associated state transitions. Protected against reentrancy by a contract-global lock.
     * @param buy Buy-side order
     * @param buySig Buy-side order signature
     * @param sell Sell-side order
     * @param sellSig Sell-side order signature
     */
    function atomicMatch(Order memory buy, Sig memory buySig, Order memory sell, Sig memory sellSig, bytes32 metadata)
        internal
        reentrancyGuard
    {
        /* CHECKS */

        /* Ensure buy order validity and calculate hash if necessary. */
        bytes32 buyHash;
        if (buy.maker == msg.sender) {
            require(validateOrderParameters(buy));
        } else {
            buyHash = _requireValidOrderWithNonce(buy, buySig);
        }

        /* Ensure sell order validity and calculate hash if necessary. */
        bytes32 sellHash;
        if (sell.maker == msg.sender) {
            require(validateOrderParameters(sell));
        } else {
            sellHash = _requireValidOrderWithNonce(sell, sellSig);
        }

        /* Must be matchable. */
        require(ordersCanMatch(buy, sell));

        /* Target must exist (prevent malicious selfdestructs just prior to order settlement). */
        uint size;
        address target = sell.target;
        assembly {
            size := extcodesize(target)
        }
        require(size > 0);

        /* Must match calldata after replacement, if specified. */
        if (buy.replacementPattern.length > 0) {
          ArrayUtils.guardedArrayReplace(buy.calldata, sell.calldata, buy.replacementPattern);
        }
        if (sell.replacementPattern.length > 0) {
          ArrayUtils.guardedArrayReplace(sell.calldata, buy.calldata, sell.replacementPattern);
        }
        require(ArrayUtils.arrayEq(buy.calldata, sell.calldata));

        /* Retrieve delegateProxy contract. */
        OwnableDelegateProxy delegateProxy = registry.proxies(sell.maker);

        /* Proxy must exist. */
        require(delegateProxy != address(0));

        /* Access the passthrough AuthenticatedProxy. */
        AuthenticatedProxy proxy = AuthenticatedProxy(delegateProxy);

        /* EFFECTS */

        /* Mark previously signed or approved orders as finalized. */
        if (msg.sender != buy.maker) {
            cancelledOrFinalized[buyHash] = true;
        }
        if (msg.sender != sell.maker) {
            cancelledOrFinalized[sellHash] = true;
        }

        /* INTERACTIONS */

        /* Execute funds transfer and pay fees. */
        uint price = executeFundsTransfer(buy, sell);

        /* Assert implementation. */
        require(delegateProxy.implementation() == registry.delegateProxyImplementation());

        /* Execute specified call through proxy. */
        require(proxy.proxy(sell.target, sell.howToCall, sell.calldata));

        /* Static calls are intentionally done after the effectful call so they can check resulting state. */

        /* Handle buy-side static call if specified. */
        if (buy.staticTarget != address(0)) {
            require(staticCall(buy.staticTarget, sell.calldata, buy.staticExtradata));
        }

        /* Handle sell-side static call if specified. */
        if (sell.staticTarget != address(0)) {
            require(staticCall(sell.staticTarget, sell.calldata, sell.staticExtradata));
        }

        /* Log match event. */
        emit OrdersMatched(buyHash, sellHash, sell.feeRecipient != address(0) ? sell.maker : buy.maker, sell.feeRecipient != address(0) ? buy.maker : sell.maker, price, metadata);
    }

    function _requireValidOrderWithNonce(Order memory order, Sig memory sig) internal view returns (bytes32) {
        return requireValidOrder(order, sig, nonces[order.maker]);
    }
}

contract Exchange is ExchangeCore {

    /**
     * @dev Call guardedArrayReplace - library function exposed for testing.
     */
    function guardedArrayReplace(bytes array, bytes desired, bytes mask)
        public
        pure
        returns (bytes)
    {
        ArrayUtils.guardedArrayReplace(array, desired, mask);
        return array;
    }

    /**
     * @dev Call calculateFinalPrice - library function exposed for testing.
     */
    function calculateFinalPrice(SaleKindInterface.Side side, SaleKindInterface.SaleKind saleKind, uint basePrice, uint extra, uint listingTime, uint expirationTime)
        public
        view
        returns (uint)
    {
        return SaleKindInterface.calculateFinalPrice(side, saleKind, basePrice, extra, listingTime, expirationTime);
    }

    /**
     * @dev Call hashOrder - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function hashOrder_(
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata)
        public
        view
        returns (bytes32)
    {
        return hashOrder(
          Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]),
          nonces[addrs[1]]
        );
    }

    /**
     * @dev Call hashToSign - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function hashToSign_(
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata)
        public
        view
        returns (bytes32)
    {
        return hashToSign(
          Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]),
          nonces[addrs[1]]
        );
    }

    /**
     * @dev Call validateOrderParameters - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function validateOrderParameters_ (
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata)
        view
        public
        returns (bool)
    {
        Order memory order = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        return validateOrderParameters(
          order
        );
    }

    /**
     * @dev Call validateOrder - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function validateOrder_ (
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata,
        uint8 v,
        bytes32 r,
        bytes32 s)
        view
        public
        returns (bool)
    {
        Order memory order = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        return validateOrder(
          hashToSign(order, nonces[order.maker]),
          order,
          Sig(v, r, s)
        );
    }

    /**
     * @dev Call approveOrder - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function approveOrder_ (
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata,
        bool orderbookInclusionDesired)
        public
    {
        Order memory order = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        return approveOrder(order, orderbookInclusionDesired);
    }

    /**
     * @dev Call cancelOrder - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function cancelOrder_(
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata,
        uint8 v,
        bytes32 r,
        bytes32 s)
        public
    {
        Order memory order = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        return cancelOrder(
          order,
          Sig(v, r, s),
          nonces[order.maker]
        );
    }

    /**
     * @dev Call cancelOrder, supplying a specific nonce — enables cancelling orders
     that were signed with nonces greater than the current nonce.
     */
    function cancelOrderWithNonce_(
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata,
        uint8 v,
        bytes32 r,
        bytes32 s,
        uint nonce)
        public
    {
        Order memory order = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        return cancelOrder(
          order,
          Sig(v, r, s),
          nonce
        );
    }

    /**
     * @dev Call calculateCurrentPrice - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function calculateCurrentPrice_(
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata)
        public
        view
        returns (uint)
    {
        return calculateCurrentPrice(
          Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8])
        );
    }

    /**
     * @dev Call ordersCanMatch - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function ordersCanMatch_(
        address[14] addrs,
        uint[18] uints,
        uint8[8] feeMethodsSidesKindsHowToCalls,
        bytes calldataBuy,
        bytes calldataSell,
        bytes replacementPatternBuy,
        bytes replacementPatternSell,
        bytes staticExtradataBuy,
        bytes staticExtradataSell)
        public
        view
        returns (bool)
    {
        Order memory buy = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], FeeMethod(feeMethodsSidesKindsHowToCalls[0]), SaleKindInterface.Side(feeMethodsSidesKindsHowToCalls[1]), SaleKindInterface.SaleKind(feeMethodsSidesKindsHowToCalls[2]), addrs[4], AuthenticatedProxy.HowToCall(feeMethodsSidesKindsHowToCalls[3]), calldataBuy, replacementPatternBuy, addrs[5], staticExtradataBuy, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        Order memory sell = Order(addrs[7], addrs[8], addrs[9], uints[9], uints[10], uints[11], uints[12], addrs[10], FeeMethod(feeMethodsSidesKindsHowToCalls[4]), SaleKindInterface.Side(feeMethodsSidesKindsHowToCalls[5]), SaleKindInterface.SaleKind(feeMethodsSidesKindsHowToCalls[6]), addrs[11], AuthenticatedProxy.HowToCall(feeMethodsSidesKindsHowToCalls[7]), calldataSell, replacementPatternSell, addrs[12], staticExtradataSell, ERC20(addrs[13]), uints[13], uints[14], uints[15], uints[16], uints[17]);
        return ordersCanMatch(
          buy,
          sell
        );
    }

    /**
     * @dev Return whether or not two orders' calldata specifications can match
     * @param buyCalldata Buy-side order calldata
     * @param buyReplacementPattern Buy-side order calldata replacement mask
     * @param sellCalldata Sell-side order calldata
     * @param sellReplacementPattern Sell-side order calldata replacement mask
     * @return Whether the orders' calldata can be matched
     */
    function orderCalldataCanMatch(bytes buyCalldata, bytes buyReplacementPattern, bytes sellCalldata, bytes sellReplacementPattern)
        public
        pure
        returns (bool)
    {
        if (buyReplacementPattern.length > 0) {
          ArrayUtils.guardedArrayReplace(buyCalldata, sellCalldata, buyReplacementPattern);
        }
        if (sellReplacementPattern.length > 0) {
          ArrayUtils.guardedArrayReplace(sellCalldata, buyCalldata, sellReplacementPattern);
        }
        return ArrayUtils.arrayEq(buyCalldata, sellCalldata);
    }

    /**
     * @dev Call calculateMatchPrice - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function calculateMatchPrice_(
        address[14] addrs,
        uint[18] uints,
        uint8[8] feeMethodsSidesKindsHowToCalls,
        bytes calldataBuy,
        bytes calldataSell,
        bytes replacementPatternBuy,
        bytes replacementPatternSell,
        bytes staticExtradataBuy,
        bytes staticExtradataSell)
        public
        view
        returns (uint)
    {
        Order memory buy = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], FeeMethod(feeMethodsSidesKindsHowToCalls[0]), SaleKindInterface.Side(feeMethodsSidesKindsHowToCalls[1]), SaleKindInterface.SaleKind(feeMethodsSidesKindsHowToCalls[2]), addrs[4], AuthenticatedProxy.HowToCall(feeMethodsSidesKindsHowToCalls[3]), calldataBuy, replacementPatternBuy, addrs[5], staticExtradataBuy, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        Order memory sell = Order(addrs[7], addrs[8], addrs[9], uints[9], uints[10], uints[11], uints[12], addrs[10], FeeMethod(feeMethodsSidesKindsHowToCalls[4]), SaleKindInterface.Side(feeMethodsSidesKindsHowToCalls[5]), SaleKindInterface.SaleKind(feeMethodsSidesKindsHowToCalls[6]), addrs[11], AuthenticatedProxy.HowToCall(feeMethodsSidesKindsHowToCalls[7]), calldataSell, replacementPatternSell, addrs[12], staticExtradataSell, ERC20(addrs[13]), uints[13], uints[14], uints[15], uints[16], uints[17]);
        return calculateMatchPrice(
          buy,
          sell
        );
    }

    /**
     * @dev Call atomicMatch - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function atomicMatch_(
        address[14] addrs,
        uint[18] uints,
        uint8[8] feeMethodsSidesKindsHowToCalls,
        bytes calldataBuy,
        bytes calldataSell,
        bytes replacementPatternBuy,
        bytes replacementPatternSell,
        bytes staticExtradataBuy,
        bytes staticExtradataSell,
        uint8[2] vs,
        bytes32[5] rssMetadata)
        public
        payable
    {

        return atomicMatch(
          Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], FeeMethod(feeMethodsSidesKindsHowToCalls[0]), SaleKindInterface.Side(feeMethodsSidesKindsHowToCalls[1]), SaleKindInterface.SaleKind(feeMethodsSidesKindsHowToCalls[2]), addrs[4], AuthenticatedProxy.HowToCall(feeMethodsSidesKindsHowToCalls[3]), calldataBuy, replacementPatternBuy, addrs[5], staticExtradataBuy, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]),
          Sig(vs[0], rssMetadata[0], rssMetadata[1]),
          Order(addrs[7], addrs[8], addrs[9], uints[9], uints[10], uints[11], uints[12], addrs[10], FeeMethod(feeMethodsSidesKindsHowToCalls[4]), SaleKindInterface.Side(feeMethodsSidesKindsHowToCalls[5]), SaleKindInterface.SaleKind(feeMethodsSidesKindsHowToCalls[6]), addrs[11], AuthenticatedProxy.HowToCall(feeMethodsSidesKindsHowToCalls[7]), calldataSell, replacementPatternSell, addrs[12], staticExtradataSell, ERC20(addrs[13]), uints[13], uints[14], uints[15], uints[16], uints[17]),
          Sig(vs[1], rssMetadata[2], rssMetadata[3]),
          rssMetadata[4]
        );
    }

}

contract WyvernExchangeWithBulkCancellations is Exchange {
    string public constant codename = "Bulk Smash";

    /**
     * @dev Initialize a WyvernExchange instance
     * @param registryAddress Address of the registry instance which this Exchange instance will use
     * @param tokenAddress Address of the token used for protocol fees
     */
    constructor (ProxyRegistry registryAddress, TokenTransferProxy tokenTransferProxyAddress, ERC20 tokenAddress, address protocolFeeAddress) public {
        registry = registryAddress;
        tokenTransferProxy = tokenTransferProxyAddress;
        exchangeToken = tokenAddress;
        protocolFeeRecipient = protocolFeeAddress;
        owner = msg.sender;
    }
}

library SaleKindInterface {

    /**
     * Side: buy or sell.
     */
    enum Side { Buy, Sell }

    /**
     * Currently supported kinds of sale: fixed price, Dutch auction.
     * English auctions cannot be supported without stronger escrow guarantees.
     * Future interesting options: Vickrey auction, nonlinear Dutch auctions.
     */
    enum SaleKind { FixedPrice, DutchAuction }

    /**
     * @dev Check whether the parameters of a sale are valid
     * @param saleKind Kind of sale
     * @param expirationTime Order expiration time
     * @return Whether the parameters were valid
     */
    function validateParameters(SaleKind saleKind, uint expirationTime)
        pure
        internal
        returns (bool)
    {
        /* Auctions must have a set expiration date. */
        return (saleKind == SaleKind.FixedPrice || expirationTime > 0);
    }

    /**
     * @dev Return whether or not an order can be settled
     * @dev Precondition: parameters have passed validateParameters
     * @param listingTime Order listing time
     * @param expirationTime Order expiration time
     */
    function canSettleOrder(uint listingTime, uint expirationTime)
        view
        internal
        returns (bool)
    {
        return (listingTime < now) && (expirationTime == 0 || now < expirationTime);
    }

    /**
     * @dev Calculate the settlement price of an order
     * @dev Precondition: parameters have passed validateParameters.
     * @param side Order side
     * @param saleKind Method of sale
     * @param basePrice Order base price
     * @param extra Order extra price data
     * @param listingTime Order listing time
     * @param expirationTime Order expiration time
     */
    function calculateFinalPrice(Side side, SaleKind saleKind, uint basePrice, uint extra, uint listingTime, uint expirationTime)
        view
        internal
        returns (uint finalPrice)
    {
        if (saleKind == SaleKind.FixedPrice) {
            return basePrice;
        } else if (saleKind == SaleKind.DutchAuction) {
            uint diff = SafeMath.div(SafeMath.mul(extra, SafeMath.sub(now, listingTime)), SafeMath.sub(expirationTime, listingTime));
            if (side == Side.Sell) {
                /* Sell-side - start price: basePrice. End price: basePrice - extra. */
                return SafeMath.sub(basePrice, diff);
            } else {
                /* Buy-side - start price: basePrice. End price: basePrice + extra. */
                return SafeMath.add(basePrice, diff);
            }
        }
    }

}

contract ProxyRegistry is Ownable {

    /* DelegateProxy implementation contract. Must be initialized. */
    address public delegateProxyImplementation;

    /* Authenticated proxies by user. */
    mapping(address => OwnableDelegateProxy) public proxies;

    /* Contracts pending access. */
    mapping(address => uint) public pending;

    /* Contracts allowed to call those proxies. */
    mapping(address => bool) public contracts;

    /* Delay period for adding an authenticated contract.
       This mitigates a particular class of potential attack on the Wyvern DAO (which owns this registry) - if at any point the value of assets held by proxy contracts exceeded the value of half the WYV supply (votes in the DAO),
       a malicious but rational attacker could buy half the Wyvern and grant themselves access to all the proxy contracts. A delay period renders this attack nonthreatening - given two weeks, if that happened, users would have
       plenty of time to notice and transfer their assets.
    */
    uint public DELAY_PERIOD = 2 weeks;

    /**
     * Start the process to enable access for specified contract. Subject to delay period.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address to which to grant permissions
     */
    function startGrantAuthentication (address addr)
        public
        onlyOwner
    {
        require(!contracts[addr] && pending[addr] == 0);
        pending[addr] = now;
    }

    /**
     * End the process to nable access for specified contract after delay period has passed.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address to which to grant permissions
     */
    function endGrantAuthentication (address addr)
        public
        onlyOwner
    {
        require(!contracts[addr] && pending[addr] != 0 && ((pending[addr] + DELAY_PERIOD) < now));
        pending[addr] = 0;
        contracts[addr] = true;
    }

    /**
     * Revoke access for specified contract. Can be done instantly.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address of which to revoke permissions
     */
    function revokeAuthentication (address addr)
        public
        onlyOwner
    {
        contracts[addr] = false;
    }

    /**
     * Register a proxy contract with this registry
     *
     * @dev Must be called by the user which the proxy is for, creates a new AuthenticatedProxy
     * @return New AuthenticatedProxy contract
     */
    function registerProxy()
        public
        returns (OwnableDelegateProxy proxy)
    {
        require(proxies[msg.sender] == address(0));
        proxy = new OwnableDelegateProxy(msg.sender, delegateProxyImplementation, abi.encodeWithSignature("initialize(address,address)", msg.sender, address(this)));
        proxies[msg.sender] = proxy;
        return proxy;
    }

}

contract TokenTransferProxy {

    /* Authentication registry. */
    ProxyRegistry public registry;

    /**
     * Call ERC20 `transferFrom`
     *
     * @dev Authenticated contract only
     * @param token ERC20 token address
     * @param from From address
     * @param to To address
     * @param amount Transfer amount
     */
    function transferFrom(address token, address from, address to, uint amount)
        public
        returns (bool)
    {
        require(registry.contracts(msg.sender));
        return ERC20(token).transferFrom(from, to, amount);
    }

}

contract OwnedUpgradeabilityStorage {

  // Current implementation
  address internal _implementation;

  // Owner of the contract
  address private _upgradeabilityOwner;

  /**
   * @dev Tells the address of the owner
   * @return the address of the owner
   */
  function upgradeabilityOwner() public view returns (address) {
    return _upgradeabilityOwner;
  }

  /**
   * @dev Sets the address of the owner
   */
  function setUpgradeabilityOwner(address newUpgradeabilityOwner) internal {
    _upgradeabilityOwner = newUpgradeabilityOwner;
  }

  /**
  * @dev Tells the address of the current implementation
  * @return address of the current implementation
  */
  function implementation() public view returns (address) {
    return _implementation;
  }

  /**
  * @dev Tells the proxy type (EIP 897)
  * @return Proxy type, 2 for forwarding proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId) {
    return 2;
  }
}

contract AuthenticatedProxy is TokenRecipient, OwnedUpgradeabilityStorage {

    /* Whether initialized. */
    bool initialized = false;

    /* Address which owns this proxy. */
    address public user;

    /* Associated registry with contract authentication information. */
    ProxyRegistry public registry;

    /* Whether access has been revoked. */
    bool public revoked;

    /* Delegate call could be used to atomically transfer multiple assets owned by the proxy contract with one order. */
    enum HowToCall { Call, DelegateCall }

    /* Event fired when the proxy access is revoked or unrevoked. */
    event Revoked(bool revoked);

    /**
     * Initialize an AuthenticatedProxy
     *
     * @param addrUser Address of user on whose behalf this proxy will act
     * @param addrRegistry Address of ProxyRegistry contract which will manage this proxy
     */
    function initialize (address addrUser, ProxyRegistry addrRegistry)
        public
    {
        require(!initialized);
        initialized = true;
        user = addrUser;
        registry = addrRegistry;
    }

    /**
     * Set the revoked flag (allows a user to revoke ProxyRegistry access)
     *
     * @dev Can be called by the user only
     * @param revoke Whether or not to revoke access
     */
    function setRevoke(bool revoke)
        public
    {
        require(msg.sender == user);
        revoked = revoke;
        emit Revoked(revoke);
    }

    /**
     * Execute a message call from the proxy contract
     *
     * @dev Can be called by the user, or by a contract authorized by the registry as long as the user has not revoked access
     * @param dest Address to which the call will be sent
     * @param howToCall Which kind of call to make
     * @param calldata Calldata to send
     * @return Result of the call (success or failure)
     */
    function proxy(address dest, HowToCall howToCall, bytes calldata)
        public
        returns (bool result)
    {
        require(msg.sender == user || (!revoked && registry.contracts(msg.sender)));
        if (howToCall == HowToCall.Call) {
            result = dest.call(calldata);
        } else if (howToCall == HowToCall.DelegateCall) {
            result = dest.delegatecall(calldata);
        }
        return result;
    }

    /**
     * Execute a message call and assert success
     *
     * @dev Same functionality as `proxy`, just asserts the return value
     * @param dest Address to which the call will be sent
     * @param howToCall What kind of call to make
     * @param calldata Calldata to send
     */
    function proxyAssert(address dest, HowToCall howToCall, bytes calldata)
        public
    {
        require(proxy(dest, howToCall, calldata));
    }

}

contract Proxy {

  /**
  * @dev Tells the address of the implementation where every call will be delegated.
  * @return address of the implementation to which it will be delegated
  */
  function implementation() public view returns (address);

  /**
  * @dev Tells the type of proxy (EIP 897)
  * @return Type of proxy, 2 for upgradeable proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId);

  /**
  * @dev Fallback function allowing to perform a delegatecall to the given implementation.
  * This function will return whatever the implementation call returns
  */
  function () payable public {
    address _impl = implementation();
    require(_impl != address(0));

    assembly {
      let ptr := mload(0x40)
      calldatacopy(ptr, 0, calldatasize)
      let result := delegatecall(gas, _impl, ptr, calldatasize, 0, 0)
      let size := returndatasize
      returndatacopy(ptr, 0, size)

      switch result
      case 0 { revert(ptr, size) }
      default { return(ptr, size) }
    }
  }
}

contract OwnedUpgradeabilityProxy is Proxy, OwnedUpgradeabilityStorage {
  /**
  * @dev Event to show ownership has been transferred
  * @param previousOwner representing the address of the previous owner
  * @param newOwner representing the address of the new owner
  */
  event ProxyOwnershipTransferred(address previousOwner, address newOwner);

  /**
  * @dev This event will be emitted every time the implementation gets upgraded
  * @param implementation representing the address of the upgraded implementation
  */
  event Upgraded(address indexed implementation);

  /**
  * @dev Upgrades the implementation address
  * @param implementation representing the address of the new implementation to be set
  */
  function _upgradeTo(address implementation) internal {
    require(_implementation != implementation);
    _implementation = implementation;
    emit Upgraded(implementation);
  }

  /**
  * @dev Throws if called by any account other than the owner.
  */
  modifier onlyProxyOwner() {
    require(msg.sender == proxyOwner());
    _;
  }

  /**
   * @dev Tells the address of the proxy owner
   * @return the address of the proxy owner
   */
  function proxyOwner() public view returns (address) {
    return upgradeabilityOwner();
  }

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferProxyOwnership(address newOwner) public onlyProxyOwner {
    require(newOwner != address(0));
    emit ProxyOwnershipTransferred(proxyOwner(), newOwner);
    setUpgradeabilityOwner(newOwner);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy.
   * @param implementation representing the address of the new implementation to be set.
   */
  function upgradeTo(address implementation) public onlyProxyOwner {
    _upgradeTo(implementation);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy
   * and delegatecall the new implementation for initialization.
   * @param implementation representing the address of the new implementation to be set.
   * @param data represents the msg.data to bet sent in the low level call. This parameter may include the function
   * signature of the implementation to be called with the needed payload
   */
  function upgradeToAndCall(address implementation, bytes data) payable public onlyProxyOwner {
    upgradeTo(implementation);
    require(address(this).delegatecall(data));
  }
}

contract OwnableDelegateProxy is OwnedUpgradeabilityProxy {

    constructor(address owner, address initialImplementation, bytes calldata)
        public
    {
        setUpgradeabilityOwner(owner);
        _upgradeTo(initialImplementation);
        require(initialImplementation.delegatecall(calldata));
    }

}

// SPDX-License-Identifier: MIT

// File: @openzeppelin/contracts/utils/cryptography/MerkleProof.sol

// OpenZeppelin Contracts (last updated v4.5.0) (utils/cryptography/MerkleProof.sol)

pragma solidity ^0.8.0;

/**
 * @dev These functions deal with verification of Merkle Trees proofs.
 *
 * The proofs can be generated using the JavaScript library
 * https://github.com/miguelmota/merkletreejs[merkletreejs].
 * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
 *
 * See `test/utils/cryptography/MerkleProof.test.js` for some examples.
 */
library MerkleProof {
    /**
     * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
     * defined by `root`. For this, a `proof` must be provided, containing
     * sibling hashes on the branch from the leaf to the root of the tree. Each
     * pair of leaves and each pair of pre-images are assumed to be sorted.
     */
    function verify(
        bytes32[] memory proof,
        bytes32 root,
        bytes32 leaf
    ) internal pure returns (bool) {
        return processProof(proof, leaf) == root;
    }

    /**
     * @dev Returns the rebuilt hash obtained by traversing a Merklee tree up
     * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
     * hash matches the root of the tree. When processing the proof, the pairs
     * of leafs & pre-images are assumed to be sorted.
     *
     * _Available since v4.4._
     */
    function processProof(bytes32[] memory proof, bytes32 leaf)
        internal
        pure
        returns (bytes32)
    {
        bytes32 computedHash = leaf;
        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];
            if (computedHash <= proofElement) {
                // Hash(current computed hash + current element of the proof)
                computedHash = _efficientHash(computedHash, proofElement);
            } else {
                // Hash(current element of the proof + current computed hash)
                computedHash = _efficientHash(proofElement, computedHash);
            }
        }
        return computedHash;
    }

    function _efficientHash(bytes32 a, bytes32 b)
        private
        pure
        returns (bytes32 value)
    {
        assembly {
            mstore(0x00, a)
            mstore(0x20, b)
            value := keccak256(0x00, 0x40)
        }
    }
}

// File: @openzeppelin/contracts/utils/Strings.sol

// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length)
        internal
        pure
        returns (string memory)
    {
        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_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}

// File: @openzeppelin/contracts/utils/Context.sol

// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with 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;
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol

// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)

pragma solidity ^0.8.0;

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

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

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

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _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 {
        require(
            newOwner != address(0),
            "Ownable: new owner is the zero address"
        );
        _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);
    }
}

// File: @openzeppelin/contracts/utils/Address.sol

// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(
            address(this).balance >= amount,
            "Address: insufficient balance"
        );

        (bool success, ) = recipient.call{value: amount}("");
        require(
            success,
            "Address: unable to send value, recipient may have reverted"
        );
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data)
        internal
        returns (bytes memory)
    {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return
            functionCallWithValue(
                target,
                data,
                value,
                "Address: low-level call with value failed"
            );
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(
            address(this).balance >= value,
            "Address: insufficient balance for call"
        );
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(
            data
        );
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data)
        internal
        view
        returns (bytes memory)
    {
        return
            functionStaticCall(
                target,
                data,
                "Address: low-level static call failed"
            );
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data)
        internal
        returns (bytes memory)
    {
        return
            functionDelegateCall(
                target,
                data,
                "Address: low-level delegate call failed"
            );
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol

// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// File: @openzeppelin/contracts/utils/introspection/IERC165.sol

// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @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);
}

// File: @openzeppelin/contracts/utils/introspection/ERC165.sol

// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override
        returns (bool)
    {
        return interfaceId == type(IERC165).interfaceId;
    }
}

// File: @openzeppelin/contracts/token/ERC721/IERC721.sol

// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(
        address indexed from,
        address indexed to,
        uint256 indexed tokenId
    );

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(
        address indexed owner,
        address indexed approved,
        uint256 indexed tokenId
    );

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(
        address indexed owner,
        address indexed operator,
        bool approved
    );

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId)
        external
        view
        returns (address operator);

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator)
        external
        view
        returns (bool);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol

// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC721/extensions/IERC721Enumerable.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {
    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index)
        external
        view
        returns (uint256);

    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256);
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol

// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {
    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);

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

    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}

// File: contracts/ERC721A.sol

// Creator: Chiru Labs
// v3.0.0

pragma solidity ^0.8.4;

error ApprovalCallerNotOwnerNorApproved();
error ApprovalQueryForNonexistentToken();
error ApproveToCaller();
error ApprovalToCurrentOwner();
error BalanceQueryForZeroAddress();
error MintedQueryForZeroAddress();
error BurnedQueryForZeroAddress();
error AuxQueryForZeroAddress();
error MintToZeroAddress();
error MintZeroQuantity();
error OwnerIndexOutOfBounds();
error OwnerQueryForNonexistentToken();
error TokenIndexOutOfBounds();
error TransferCallerNotOwnerNorApproved();
error TransferFromIncorrectOwner();
error TransferToNonERC721ReceiverImplementer();
error TransferToZeroAddress();
error URIQueryForNonexistentToken();

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension. Built to optimize for lower gas during batch mints.
 *
 * Assumes serials are sequentially minted starting at _startTokenId() (defaults to 0, e.g. 0, 1, 2, 3..).
 *
 * Assumes that an owner cannot have more than 2**64 - 1 (max value of uint64) of supply.
 *
 * Assumes that the maximum token id cannot exceed 2**256 - 1 (max value of uint256).
 */
contract ERC721A is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;

    // Compiler will pack this into a single 256bit word.
    struct TokenOwnership {
        // The address of the owner.
        address addr;
        // Keeps track of the start time of ownership with minimal overhead for tokenomics.
        uint64 startTimestamp;
        // Whether the token has been burned.
        bool burned;
    }

    // Compiler will pack this into a single 256bit word.
    struct AddressData {
        // Realistically, 2**64-1 is more than enough.
        uint64 balance;
        // Keeps track of mint count with minimal overhead for tokenomics.
        uint64 numberMinted;
        // Keeps track of burn count with minimal overhead for tokenomics.
        uint64 numberBurned;
        // For miscellaneous variable(s) pertaining to the address
        // (e.g. number of whitelist mint slots used).
        // If there are multiple variables, please pack them into a uint64.
        uint64 aux;
    }

    // The tokenId of the next token to be minted.
    uint256 internal _currentIndex;

    // The number of tokens burned.
    uint256 internal _burnCounter;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Mapping from token ID to ownership details
    // An empty struct value does not necessarily mean the token is unowned. See ownershipOf implementation for details.
    mapping(uint256 => TokenOwnership) internal _ownerships;

    // Mapping owner address to address data
    mapping(address => AddressData) private _addressData;

    // Mapping from token ID to approved address
    mapping(uint256 => address) private _tokenApprovals;

    // Mapping from owner to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
        _currentIndex = _startTokenId();
    }

    /**
     * To change the starting tokenId, please override this function.
     */
    function _startTokenId() internal view virtual returns (uint256) {
        return 0;
    }

    /**
     * @dev See {IERC721Enumerable-totalSupply}.
     * @dev Burned tokens are calculated here, use _totalMinted() if you want to count just minted tokens.
     */
    function totalSupply() public view returns (uint256) {
        // Counter underflow is impossible as _burnCounter cannot be incremented
        // more than _currentIndex - _startTokenId() times
        unchecked {
            return _currentIndex - _burnCounter - _startTokenId();
        }
    }

    /**
     * Returns the total amount of tokens minted in the contract.
     */
    function _totalMinted() internal view returns (uint256) {
        // Counter underflow is impossible as _currentIndex does not decrement,
        // and it is initialized to _startTokenId()
        unchecked {
            return _currentIndex - _startTokenId();
        }
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override(ERC165, IERC165)
        returns (bool)
    {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view override returns (uint256) {
        if (owner == address(0)) revert BalanceQueryForZeroAddress();
        return uint256(_addressData[owner].balance);
    }

    /**
     * Returns the number of tokens minted by `owner`.
     */
    function _numberMinted(address owner) internal view returns (uint256) {
        if (owner == address(0)) revert MintedQueryForZeroAddress();
        return uint256(_addressData[owner].numberMinted);
    }

    /**
     * Returns the number of tokens burned by or on behalf of `owner`.
     */
    function _numberBurned(address owner) internal view returns (uint256) {
        if (owner == address(0)) revert BurnedQueryForZeroAddress();
        return uint256(_addressData[owner].numberBurned);
    }

    /**
     * Returns the auxillary data for `owner`. (e.g. number of whitelist mint slots used).
     */
    function _getAux(address owner) internal view returns (uint64) {
        if (owner == address(0)) revert AuxQueryForZeroAddress();
        return _addressData[owner].aux;
    }

    /**
     * Sets the auxillary data for `owner`. (e.g. number of whitelist mint slots used).
     * If there are multiple variables, please pack them into a uint64.
     */
    function _setAux(address owner, uint64 aux) internal {
        if (owner == address(0)) revert AuxQueryForZeroAddress();
        _addressData[owner].aux = aux;
    }

    /**
     * Gas spent here starts off proportional to the maximum mint batch size.
     * It gradually moves to O(1) as tokens get transferred around in the collection over time.
     */
    function ownershipOf(uint256 tokenId)
        internal
        view
        returns (TokenOwnership memory)
    {
        uint256 curr = tokenId;

        unchecked {
            if (_startTokenId() <= curr && curr < _currentIndex) {
                TokenOwnership memory ownership = _ownerships[curr];
                if (!ownership.burned) {
                    if (ownership.addr != address(0)) {
                        return ownership;
                    }
                    // Invariant:
                    // There will always be an ownership that has an address and is not burned
                    // before an ownership that does not have an address and is not burned.
                    // Hence, curr will not underflow.
                    while (true) {
                        curr--;
                        ownership = _ownerships[curr];
                        if (ownership.addr != address(0)) {
                            return ownership;
                        }
                    }
                }
            }
        }
        revert OwnerQueryForNonexistentToken();
    }

    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view override returns (address) {
        return ownershipOf(tokenId).addr;
    }

    /**
     * @dev See {IERC721Metadata-name}.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev See {IERC721Metadata-symbol}.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId)
        public
        view
        virtual
        override
        returns (string memory)
    {
        if (!_exists(tokenId)) revert URIQueryForNonexistentToken();

        string memory baseURI = _baseURI();
        return
            bytes(baseURI).length != 0
                ? string(abi.encodePacked(baseURI, tokenId.toString()))
                : "";
    }

    /**
     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
     * by default, can be overriden in child contracts.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return "";
    }

    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public override {
        address owner = ERC721A.ownerOf(tokenId);
        if (to == owner) revert ApprovalToCurrentOwner();

        if (_msgSender() != owner && !isApprovedForAll(owner, _msgSender())) {
            revert ApprovalCallerNotOwnerNorApproved();
        }

        _approve(to, tokenId, owner);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId)
        public
        view
        override
        returns (address)
    {
        if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();

        return _tokenApprovals[tokenId];
    }

    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved)
        public
        override
    {
        if (operator == _msgSender()) revert ApproveToCaller();

        _operatorApprovals[_msgSender()][operator] = approved;
        emit ApprovalForAll(_msgSender(), operator, approved);
    }

    /**
     * @dev See {IERC721-isApprovedForAll}.
     */
    function isApprovedForAll(address owner, address operator)
        public
        view
        virtual
        override
        returns (bool)
    {
        return _operatorApprovals[owner][operator];
    }

    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        _transfer(from, to, tokenId);
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        safeTransferFrom(from, to, tokenId, "");
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) public virtual override {
        _transfer(from, to, tokenId);
        if (
            to.isContract() &&
            !_checkContractOnERC721Received(from, to, tokenId, _data)
        ) {
            revert TransferToNonERC721ReceiverImplementer();
        }
    }

    /**
     * @dev Returns whether `tokenId` exists.
     *
     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
     *
     * Tokens start existing when they are minted (`_mint`),
     */
    function _exists(uint256 tokenId) internal view returns (bool) {
        return
            _startTokenId() <= tokenId &&
            tokenId < _currentIndex &&
            !_ownerships[tokenId].burned;
    }

    function _safeMint(address to, uint256 quantity) internal {
        _safeMint(to, quantity, "");
    }

    /**
     * @dev Safely mints `quantity` tokens and transfers them to `to`.
     *
     * Requirements:
     *
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called for each safe transfer.
     * - `quantity` must be greater than 0.
     *
     * Emits a {Transfer} event.
     */
    function _safeMint(
        address to,
        uint256 quantity,
        bytes memory _data
    ) internal {
        _mint(to, quantity, _data, true);
    }

    /**
     * @dev Mints `quantity` tokens and transfers them to `to`.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `quantity` must be greater than 0.
     *
     * Emits a {Transfer} event.
     */
    function _mint(
        address to,
        uint256 quantity,
        bytes memory _data,
        bool safe
    ) internal {
        uint256 startTokenId = _currentIndex;
        if (to == address(0)) revert MintToZeroAddress();
        if (quantity == 0) revert MintZeroQuantity();

        _beforeTokenTransfers(address(0), to, startTokenId, quantity);

        // Overflows are incredibly unrealistic.
        // balance or numberMinted overflow if current value of either + quantity > 1.8e19 (2**64) - 1
        // updatedIndex overflows if _currentIndex + quantity > 1.2e77 (2**256) - 1
        unchecked {
            _addressData[to].balance += uint64(quantity);
            _addressData[to].numberMinted += uint64(quantity);

            _ownerships[startTokenId].addr = to;
            _ownerships[startTokenId].startTimestamp = uint64(block.timestamp);

            uint256 updatedIndex = startTokenId;
            uint256 end = updatedIndex + quantity;

            if (safe && to.isContract()) {
                do {
                    emit Transfer(address(0), to, updatedIndex);
                    if (
                        !_checkContractOnERC721Received(
                            address(0),
                            to,
                            updatedIndex++,
                            _data
                        )
                    ) {
                        revert TransferToNonERC721ReceiverImplementer();
                    }
                } while (updatedIndex != end);
                // Reentrancy protection
                if (_currentIndex != startTokenId) revert();
            } else {
                do {
                    emit Transfer(address(0), to, updatedIndex++);
                } while (updatedIndex != end);
            }
            _currentIndex = updatedIndex;
        }
        _afterTokenTransfers(address(0), to, startTokenId, quantity);
    }

    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     *
     * Emits a {Transfer} event.
     */
    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) private {
        TokenOwnership memory prevOwnership = ownershipOf(tokenId);

        bool isApprovedOrOwner = (_msgSender() == prevOwnership.addr ||
            isApprovedForAll(prevOwnership.addr, _msgSender()) ||
            getApproved(tokenId) == _msgSender());

        if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
        if (prevOwnership.addr != from) revert TransferFromIncorrectOwner();
        if (to == address(0)) revert TransferToZeroAddress();

        _beforeTokenTransfers(from, to, tokenId, 1);

        // Clear approvals from the previous owner
        _approve(address(0), tokenId, prevOwnership.addr);

        // Underflow of the sender's balance is impossible because we check for
        // ownership above and the recipient's balance can't realistically overflow.
        // Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
        unchecked {
            _addressData[from].balance -= 1;
            _addressData[to].balance += 1;

            _ownerships[tokenId].addr = to;
            _ownerships[tokenId].startTimestamp = uint64(block.timestamp);

            // If the ownership slot of tokenId+1 is not explicitly set, that means the transfer initiator owns it.
            // Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
            uint256 nextTokenId = tokenId + 1;
            if (_ownerships[nextTokenId].addr == address(0)) {
                // This will suffice for checking _exists(nextTokenId),
                // as a burned slot cannot contain the zero address.
                if (nextTokenId < _currentIndex) {
                    _ownerships[nextTokenId].addr = prevOwnership.addr;
                    _ownerships[nextTokenId].startTimestamp = prevOwnership
                        .startTimestamp;
                }
            }
        }

        emit Transfer(from, to, tokenId);
        _afterTokenTransfers(from, to, tokenId, 1);
    }

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual {
        TokenOwnership memory prevOwnership = ownershipOf(tokenId);

        _beforeTokenTransfers(prevOwnership.addr, address(0), tokenId, 1);

        // Clear approvals from the previous owner
        _approve(address(0), tokenId, prevOwnership.addr);

        // Underflow of the sender's balance is impossible because we check for
        // ownership above and the recipient's balance can't realistically overflow.
        // Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
        unchecked {
            _addressData[prevOwnership.addr].balance -= 1;
            _addressData[prevOwnership.addr].numberBurned += 1;

            // Keep track of who burned the token, and the timestamp of burning.
            _ownerships[tokenId].addr = prevOwnership.addr;
            _ownerships[tokenId].startTimestamp = uint64(block.timestamp);
            _ownerships[tokenId].burned = true;

            // If the ownership slot of tokenId+1 is not explicitly set, that means the burn initiator owns it.
            // Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
            uint256 nextTokenId = tokenId + 1;
            if (_ownerships[nextTokenId].addr == address(0)) {
                // This will suffice for checking _exists(nextTokenId),
                // as a burned slot cannot contain the zero address.
                if (nextTokenId < _currentIndex) {
                    _ownerships[nextTokenId].addr = prevOwnership.addr;
                    _ownerships[nextTokenId].startTimestamp = prevOwnership
                        .startTimestamp;
                }
            }
        }

        emit Transfer(prevOwnership.addr, address(0), tokenId);
        _afterTokenTransfers(prevOwnership.addr, address(0), tokenId, 1);

        // Overflow not possible, as _burnCounter cannot be exceed _currentIndex times.
        unchecked {
            _burnCounter++;
        }
    }

    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * Emits a {Approval} event.
     */
    function _approve(
        address to,
        uint256 tokenId,
        address owner
    ) private {
        _tokenApprovals[tokenId] = to;
        emit Approval(owner, to, tokenId);
    }

    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param _data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    function _checkContractOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) private returns (bool) {
        try
            IERC721Receiver(to).onERC721Received(
                _msgSender(),
                from,
                tokenId,
                _data
            )
        returns (bytes4 retval) {
            return retval == IERC721Receiver(to).onERC721Received.selector;
        } catch (bytes memory reason) {
            if (reason.length == 0) {
                revert TransferToNonERC721ReceiverImplementer();
            } else {
                assembly {
                    revert(add(32, reason), mload(reason))
                }
            }
        }
    }

    /**
     * @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.
     * And also called before burning one token.
     *
     * startTokenId - the first token id to be transferred
     * quantity - the amount to be transferred
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, `from`'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, `tokenId` will be burned by `from`.
     * - `from` and `to` are never both zero.
     */
    function _beforeTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual {}

    /**
     * @dev Hook that is called after a set of serially-ordered token ids have been transferred. This includes
     * minting.
     * And also called after one token has been burned.
     *
     * startTokenId - the first token id to be transferred
     * quantity - the amount to be transferred
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, `from`'s `tokenId` has been
     * transferred to `to`.
     * - When `from` is zero, `tokenId` has been minted for `to`.
     * - When `to` is zero, `tokenId` has been burned by `from`.
     * - `from` and `to` are never both zero.
     */
    function _afterTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual {}
}

// File: contracts/SpaceRiders.sol

pragma solidity >=0.8.0 <0.9.0;

interface StarToken {
    function updateRewardOnMint(address _to, uint256 _amount) external;

    function updateReward(address _from, address _to) external;

    function getReward(address _to) external;

    function spend(address _from, uint256 _amount) external;
}

contract SpaceRiders is ERC721A, Ownable {
    using Strings for uint256;
    using MerkleProof for bytes32[];

    bytes32 merkleRoot;

    string public baseURI;
    string public notRevealedUri;

    bool public isPaused = true;
    bool public isRevealed = false;
    bool public isOnlyWhitelisted = true;

    uint256 public constant MAX_SUPPLY = 8888;
    uint256 public constant WHITELIST_MAX_MINT_AMOUNT = 2;
    uint256 public constant WHITELIST_MAX_TX_MINT_AMOUNT = 2;
    uint256 public constant MAX_TX_MINT_AMOUNT = 2;
    uint256 public maxMintAmount = 4;
    uint256 public cost = 0.05 ether;
    uint256 public marketingSupply = 100;

    StarToken public starToken;

    event NewSpaceRiderMinted(address sender, uint256 mintAmount);

    constructor(
        string memory _name,
        string memory _symbol,
        string memory _initNotRevealedUri
    ) ERC721A(_name, _symbol) {
        setNotRevealedURI(_initNotRevealedUri);
    }

    modifier mustPassChecks(uint256 _mintAmount) {
        require(
            (!isPaused || msg.sender == owner()) &&
                _mintAmount > 0 &&
                (_mintAmount <= MAX_TX_MINT_AMOUNT) &&
                totalSupply() + _mintAmount <= MAX_SUPPLY - marketingSupply,
            isPaused
                ? "Sale is paused"
                : (
                    _mintAmount == 0
                        ? "You need to mint at least 1"
                        : (
                            _mintAmount > MAX_TX_MINT_AMOUNT
                                ? "Max transaction mint amount exceed"
                                : "Supply limit exceeded"
                        )
                )
        );
        if (isOnlyWhitelisted == true) {
            require(
                _mintAmount <= WHITELIST_MAX_TX_MINT_AMOUNT &&
                    _numberMinted(msg.sender) + _mintAmount <=
                    WHITELIST_MAX_MINT_AMOUNT,
                _mintAmount > WHITELIST_MAX_TX_MINT_AMOUNT
                    ? "Whitelist max transaction mint amount exceed"
                    : "Whitelist max mint amount exceed"
            );
        } else {
            require(
                _numberMinted(msg.sender) + _mintAmount <= maxMintAmount,
                "Max mint amount exceed"
            );
        }
        require(
            msg.value >= cost * _mintAmount || msg.sender == owner(),
            "Insufficient funds"
        );
        _;
    }

    function _startTokenId() internal view virtual override returns (uint256) {
        return 1;
    }

    function _baseURI() internal view virtual override returns (string memory) {
        return baseURI;
    }

    function tokenURI(uint256 tokenId)
        public
        view
        virtual
        override
        returns (string memory)
    {
        require(_exists(tokenId));
        if (isRevealed == false) {
            return notRevealedUri;
        }
        string memory currentBaseURI = _baseURI();
        return
            bytes(currentBaseURI).length > 0
                ? string(
                    abi.encodePacked(
                        currentBaseURI,
                        tokenId.toString(),
                        ".json"
                    )
                )
                : "";
    }

    function _processMint(uint256 _mintAmount) internal {
        _safeMint(msg.sender, _mintAmount);
        emit NewSpaceRiderMinted(msg.sender, _mintAmount);
        starToken.updateRewardOnMint(msg.sender, _mintAmount);
    }

    function mint(uint256 _mintAmount)
        public
        payable
        mustPassChecks(_mintAmount)
    {
        require(
            isOnlyWhitelisted == false || msg.sender == owner(),
            "Whitelist only"
        );
        _processMint(_mintAmount);
    }

    function presaleMint(uint256 _mintAmount, bytes32[] memory proof)
        public
        payable
        mustPassChecks(_mintAmount)
    {
        require(
            (isOnlyWhitelisted == true &&
                proof.verify(
                    merkleRoot,
                    keccak256(abi.encodePacked(msg.sender))
                )) || msg.sender == owner(),
            !isOnlyWhitelisted ? "Whitelist sale ended" : "Not whitelisted"
        );
        _processMint(_mintAmount);
    }

    function walletOfOwner(address _owner)
        public
        view
        returns (uint256[] memory)
    {
        uint256 ownerTokenCount = balanceOf(_owner);
        uint256[] memory ownedTokenIds = new uint256[](ownerTokenCount);
        uint256 currentTokenId = _startTokenId();
        uint256 ownedTokenIndex = 0;
        address latestOwnerAddress;

        while (
            ownedTokenIndex < ownerTokenCount && currentTokenId <= MAX_SUPPLY
        ) {
            TokenOwnership memory ownership = _ownerships[currentTokenId];

            if (!ownership.burned && ownership.addr != address(0)) {
                latestOwnerAddress = ownership.addr;
            }

            if (latestOwnerAddress == _owner) {
                ownedTokenIds[ownedTokenIndex] = currentTokenId;

                ownedTokenIndex++;
            }

            currentTokenId++;
        }
        return ownedTokenIds;
    }

    function mintedTotalOf(address _owner) public view returns (uint256) {
        return _numberMinted(_owner);
    }

    function toggleIsPaused() public onlyOwner {
        isPaused = !isPaused;
    }

    function toggleIsOnlyWhitelisted() public onlyOwner {
        isOnlyWhitelisted = !isOnlyWhitelisted;
    }

    function toggleIsRevealed() public onlyOwner {
        if (!isRevealed) require(bytes(baseURI).length > 0, "BaseURI not set");
        isRevealed = !isRevealed;
    }

    function setToken(address _contract) external onlyOwner {
        starToken = StarToken(_contract);
    }

    function setCost(uint256 _newCost) public onlyOwner {
        cost = _newCost;
    }

    function setMaxMintAmount(uint256 _newMaxMintAmount) public onlyOwner {
        maxMintAmount = _newMaxMintAmount;
    }

    function setMarketingSupply(uint256 _newMarketingSupply) public onlyOwner {
        require(
            _newMarketingSupply <= MAX_SUPPLY - totalSupply(),
            "Must be less than remaining supply"
        );
        marketingSupply = _newMarketingSupply;
    }

    function setMerkleRoot(bytes32 root) public onlyOwner {
        merkleRoot = root;
    }

    function setNotRevealedURI(string memory _notRevealedURI) public onlyOwner {
        notRevealedUri = _notRevealedURI;
    }

    function setBaseURI(string memory _newBaseURI) public onlyOwner {
        baseURI = _newBaseURI;
    }

    function airdrop(address[] calldata _users) public payable onlyOwner {
        require(
            marketingSupply > 0 &&
                _users.length <= marketingSupply &&
                _users.length > 0 &&
                (totalSupply() + _users.length < MAX_SUPPLY - marketingSupply),
            marketingSupply <= 0
                ? "Marketing supply empty"
                : (
                    _users.length > marketingSupply
                        ? "Addresses exceed marketing supply"
                        : (
                            _users.length == 0
                                ? "At least 1 address required"
                                : "Supply limit exceeded"
                        )
                )
        );

        for (uint256 i = 0; i < _users.length; i++) {
            _safeMint(_users[i], 1);
            emit NewSpaceRiderMinted(_users[i], 1);
            --marketingSupply;
            starToken.updateReward(address(0), _users[i]);
        }
    }

    function withdraw() public payable onlyOwner {
        uint256 balance = address(this).balance;
        require(balance > 0, "No balance to withdraw");
        (bool successA, ) = payable(0x077aC19FF94d46F7155Ea660C92ab53bf8868763)
            .call{value: (balance / 100) * 20}("");
        (bool successB, ) = payable(0xCaD5307601377933A39cBd364581C57c7B7e6799)
            .call{value: (balance / 100) * 20}("");
        (bool successC, ) = payable(0x51D8f89Fae2e82c4bAcF6Ec270f36624bc9C6D1E)
            .call{value: (balance / 100) * 15}("");
        (bool successD, ) = payable(0x47aE9C38436D895529054A253CF55F5fCe03C369)
            .call{value: (balance / 100) * 5}("");
        (bool successE, ) = payable(0x2A76bAA2F2cFB1b17aE672C995B3C41398e86cCD)
            .call{value: (balance / 100) * 40}("");
        require(
            successA && successB && successC && successD && successE,
            "Withdraw failed"
        );
        assert(address(this).balance == 0);
    }

    function claimTokens() external {
        starToken.updateReward(msg.sender, address(0));
        starToken.getReward(msg.sender);
    }

    function spendTokens(uint256 _amount) external {
        starToken.spend(msg.sender, _amount);
    }

    function _beforeTokenTransfers(
        address from,
        address to,
        uint256 tokenId,
        uint256 quantity
    ) internal virtual override {
        super._beforeTokenTransfers(from, to, tokenId, quantity);
        if (from != address(0)) {
            starToken.updateReward(from, to);
        }
    }
}

pragma solidity ^0.4.13;

contract Ownable {
  address public owner;


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


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  constructor() public {
    owner = msg.sender;
  }

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

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipRenounced(owner);
    owner = address(0);
  }
}

contract ERC20Basic {
  function totalSupply() public view returns (uint256);
  function balanceOf(address who) public view returns (uint256);
  function transfer(address to, uint256 value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}

contract ERC20 is ERC20Basic {
  function allowance(address owner, address spender)
    public view returns (uint256);

  function transferFrom(address from, address to, uint256 value)
    public returns (bool);

  function approve(address spender, uint256 value) public returns (bool);
  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

contract TokenRecipient {
    event ReceivedEther(address indexed sender, uint amount);
    event ReceivedTokens(address indexed from, uint256 value, address indexed token, bytes extraData);

    /**
     * @dev Receive tokens and generate a log event
     * @param from Address from which to transfer tokens
     * @param value Amount of tokens to transfer
     * @param token Address of token
     * @param extraData Additional data to log
     */
    function receiveApproval(address from, uint256 value, address token, bytes extraData) public {
        ERC20 t = ERC20(token);
        require(t.transferFrom(from, this, value));
        emit ReceivedTokens(from, value, token, extraData);
    }

    /**
     * @dev Receive Ether and generate a log event
     */
    function () payable public {
        emit ReceivedEther(msg.sender, msg.value);
    }
}

contract ProxyRegistry is Ownable {

    /* DelegateProxy implementation contract. Must be initialized. */
    address public delegateProxyImplementation;

    /* Authenticated proxies by user. */
    mapping(address => OwnableDelegateProxy) public proxies;

    /* Contracts pending access. */
    mapping(address => uint) public pending;

    /* Contracts allowed to call those proxies. */
    mapping(address => bool) public contracts;

    /* Delay period for adding an authenticated contract.
       This mitigates a particular class of potential attack on the Wyvern DAO (which owns this registry) - if at any point the value of assets held by proxy contracts exceeded the value of half the WYV supply (votes in the DAO),
       a malicious but rational attacker could buy half the Wyvern and grant themselves access to all the proxy contracts. A delay period renders this attack nonthreatening - given two weeks, if that happened, users would have
       plenty of time to notice and transfer their assets.
    */
    uint public DELAY_PERIOD = 2 weeks;

    /**
     * Start the process to enable access for specified contract. Subject to delay period.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address to which to grant permissions
     */
    function startGrantAuthentication (address addr)
        public
        onlyOwner
    {
        require(!contracts[addr] && pending[addr] == 0);
        pending[addr] = now;
    }

    /**
     * End the process to nable access for specified contract after delay period has passed.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address to which to grant permissions
     */
    function endGrantAuthentication (address addr)
        public
        onlyOwner
    {
        require(!contracts[addr] && pending[addr] != 0 && ((pending[addr] + DELAY_PERIOD) < now));
        pending[addr] = 0;
        contracts[addr] = true;
    }

    /**
     * Revoke access for specified contract. Can be done instantly.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address of which to revoke permissions
     */    
    function revokeAuthentication (address addr)
        public
        onlyOwner
    {
        contracts[addr] = false;
    }

    /**
     * Register a proxy contract with this registry
     *
     * @dev Must be called by the user which the proxy is for, creates a new AuthenticatedProxy
     * @return New AuthenticatedProxy contract
     */
    function registerProxy()
        public
        returns (OwnableDelegateProxy proxy)
    {
        require(proxies[msg.sender] == address(0));
        proxy = new OwnableDelegateProxy(msg.sender, delegateProxyImplementation, abi.encodeWithSignature("initialize(address,address)", msg.sender, address(this)));
        proxies[msg.sender] = proxy;
        return proxy;
    }

}

contract WyvernProxyRegistry is ProxyRegistry {

    string public constant name = "Project Wyvern Proxy Registry";

    /* Whether the initial auth address has been set. */
    bool public initialAddressSet = false;

    constructor ()
        public
    {
        delegateProxyImplementation = new AuthenticatedProxy();
    }

    /** 
     * Grant authentication to the initial Exchange protocol contract
     *
     * @dev No delay, can only be called once - after that the standard registry process with a delay must be used
     * @param authAddress Address of the contract to grant authentication
     */
    function grantInitialAuthentication (address authAddress)
        onlyOwner
        public
    {
        require(!initialAddressSet);
        initialAddressSet = true;
        contracts[authAddress] = true;
    }

}

contract OwnedUpgradeabilityStorage {

  // Current implementation
  address internal _implementation;

  // Owner of the contract
  address private _upgradeabilityOwner;

  /**
   * @dev Tells the address of the owner
   * @return the address of the owner
   */
  function upgradeabilityOwner() public view returns (address) {
    return _upgradeabilityOwner;
  }

  /**
   * @dev Sets the address of the owner
   */
  function setUpgradeabilityOwner(address newUpgradeabilityOwner) internal {
    _upgradeabilityOwner = newUpgradeabilityOwner;
  }

  /**
  * @dev Tells the address of the current implementation
  * @return address of the current implementation
  */
  function implementation() public view returns (address) {
    return _implementation;
  }

  /**
  * @dev Tells the proxy type (EIP 897)
  * @return Proxy type, 2 for forwarding proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId) {
    return 2;
  }
}

contract AuthenticatedProxy is TokenRecipient, OwnedUpgradeabilityStorage {

    /* Whether initialized. */
    bool initialized = false;

    /* Address which owns this proxy. */
    address public user;

    /* Associated registry with contract authentication information. */
    ProxyRegistry public registry;

    /* Whether access has been revoked. */
    bool public revoked;

    /* Delegate call could be used to atomically transfer multiple assets owned by the proxy contract with one order. */
    enum HowToCall { Call, DelegateCall }

    /* Event fired when the proxy access is revoked or unrevoked. */
    event Revoked(bool revoked);

    /**
     * Initialize an AuthenticatedProxy
     *
     * @param addrUser Address of user on whose behalf this proxy will act
     * @param addrRegistry Address of ProxyRegistry contract which will manage this proxy
     */
    function initialize (address addrUser, ProxyRegistry addrRegistry)
        public
    {
        require(!initialized);
        initialized = true;
        user = addrUser;
        registry = addrRegistry;
    }

    /**
     * Set the revoked flag (allows a user to revoke ProxyRegistry access)
     *
     * @dev Can be called by the user only
     * @param revoke Whether or not to revoke access
     */
    function setRevoke(bool revoke)
        public
    {
        require(msg.sender == user);
        revoked = revoke;
        emit Revoked(revoke);
    }

    /**
     * Execute a message call from the proxy contract
     *
     * @dev Can be called by the user, or by a contract authorized by the registry as long as the user has not revoked access
     * @param dest Address to which the call will be sent
     * @param howToCall Which kind of call to make
     * @param calldata Calldata to send
     * @return Result of the call (success or failure)
     */
    function proxy(address dest, HowToCall howToCall, bytes calldata)
        public
        returns (bool result)
    {
        require(msg.sender == user || (!revoked && registry.contracts(msg.sender)));
        if (howToCall == HowToCall.Call) {
            result = dest.call(calldata);
        } else if (howToCall == HowToCall.DelegateCall) {
            result = dest.delegatecall(calldata);
        }
        return result;
    }

    /**
     * Execute a message call and assert success
     * 
     * @dev Same functionality as `proxy`, just asserts the return value
     * @param dest Address to which the call will be sent
     * @param howToCall What kind of call to make
     * @param calldata Calldata to send
     */
    function proxyAssert(address dest, HowToCall howToCall, bytes calldata)
        public
    {
        require(proxy(dest, howToCall, calldata));
    }

}

contract Proxy {

  /**
  * @dev Tells the address of the implementation where every call will be delegated.
  * @return address of the implementation to which it will be delegated
  */
  function implementation() public view returns (address);

  /**
  * @dev Tells the type of proxy (EIP 897)
  * @return Type of proxy, 2 for upgradeable proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId);

  /**
  * @dev Fallback function allowing to perform a delegatecall to the given implementation.
  * This function will return whatever the implementation call returns
  */
  function () payable public {
    address _impl = implementation();
    require(_impl != address(0));

    assembly {
      let ptr := mload(0x40)
      calldatacopy(ptr, 0, calldatasize)
      let result := delegatecall(gas, _impl, ptr, calldatasize, 0, 0)
      let size := returndatasize
      returndatacopy(ptr, 0, size)

      switch result
      case 0 { revert(ptr, size) }
      default { return(ptr, size) }
    }
  }
}

contract OwnedUpgradeabilityProxy is Proxy, OwnedUpgradeabilityStorage {
  /**
  * @dev Event to show ownership has been transferred
  * @param previousOwner representing the address of the previous owner
  * @param newOwner representing the address of the new owner
  */
  event ProxyOwnershipTransferred(address previousOwner, address newOwner);

  /**
  * @dev This event will be emitted every time the implementation gets upgraded
  * @param implementation representing the address of the upgraded implementation
  */
  event Upgraded(address indexed implementation);

  /**
  * @dev Upgrades the implementation address
  * @param implementation representing the address of the new implementation to be set
  */
  function _upgradeTo(address implementation) internal {
    require(_implementation != implementation);
    _implementation = implementation;
    emit Upgraded(implementation);
  }

  /**
  * @dev Throws if called by any account other than the owner.
  */
  modifier onlyProxyOwner() {
    require(msg.sender == proxyOwner());
    _;
  }

  /**
   * @dev Tells the address of the proxy owner
   * @return the address of the proxy owner
   */
  function proxyOwner() public view returns (address) {
    return upgradeabilityOwner();
  }

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferProxyOwnership(address newOwner) public onlyProxyOwner {
    require(newOwner != address(0));
    emit ProxyOwnershipTransferred(proxyOwner(), newOwner);
    setUpgradeabilityOwner(newOwner);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy.
   * @param implementation representing the address of the new implementation to be set.
   */
  function upgradeTo(address implementation) public onlyProxyOwner {
    _upgradeTo(implementation);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy
   * and delegatecall the new implementation for initialization.
   * @param implementation representing the address of the new implementation to be set.
   * @param data represents the msg.data to bet sent in the low level call. This parameter may include the function
   * signature of the implementation to be called with the needed payload
   */
  function upgradeToAndCall(address implementation, bytes data) payable public onlyProxyOwner {
    upgradeTo(implementation);
    require(address(this).delegatecall(data));
  }
}

contract OwnableDelegateProxy is OwnedUpgradeabilityProxy {

    constructor(address owner, address initialImplementation, bytes calldata)
        public
    {
        setUpgradeabilityOwner(owner);
        _upgradeTo(initialImplementation);
        require(initialImplementation.delegatecall(calldata));
    }

}

contract OwnedUpgradeabilityStorage {

  // Current implementation
  address internal _implementation;

  // Owner of the contract
  address private _upgradeabilityOwner;

  /**
   * @dev Tells the address of the owner
   * @return the address of the owner
   */
  function upgradeabilityOwner() public view returns (address) {
    return _upgradeabilityOwner;
  }

  /**
   * @dev Sets the address of the owner
   */
  function setUpgradeabilityOwner(address newUpgradeabilityOwner) internal {
    _upgradeabilityOwner = newUpgradeabilityOwner;
  }

  /**
  * @dev Tells the address of the current implementation
  * @return address of the current implementation
  */
  function implementation() public view returns (address) {
    return _implementation;
  }

  /**
  * @dev Tells the proxy type (EIP 897)
  * @return Proxy type, 2 for forwarding proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId) {
    return 2;
  }
}



contract Proxy {

  /**
  * @dev Tells the address of the implementation where every call will be delegated.
  * @return address of the implementation to which it will be delegated
  */
  function implementation() public view returns (address);

  /**
  * @dev Tells the type of proxy (EIP 897)
  * @return Type of proxy, 2 for upgradeable proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId);

  /**
  * @dev Fallback function allowing to perform a delegatecall to the given implementation.
  * This function will return whatever the implementation call returns
  */
  function () payable public {
    address _impl = implementation();
    require(_impl != address(0));

    assembly {
      let ptr := mload(0x40)
      calldatacopy(ptr, 0, calldatasize)
      let result := delegatecall(gas, _impl, ptr, calldatasize, 0, 0)
      let size := returndatasize
      returndatacopy(ptr, 0, size)

      switch result
      case 0 { revert(ptr, size) }
      default { return(ptr, size) }
    }
  }
}

contract OwnedUpgradeabilityProxy is Proxy, OwnedUpgradeabilityStorage {
  /**
  * @dev Event to show ownership has been transferred
  * @param previousOwner representing the address of the previous owner
  * @param newOwner representing the address of the new owner
  */
  event ProxyOwnershipTransferred(address previousOwner, address newOwner);

  /**
  * @dev This event will be emitted every time the implementation gets upgraded
  * @param implementation representing the address of the upgraded implementation
  */
  event Upgraded(address indexed implementation);

  /**
  * @dev Upgrades the implementation address
  * @param implementation representing the address of the new implementation to be set
  */
  function _upgradeTo(address implementation) internal {
    require(_implementation != implementation);
    _implementation = implementation;
    emit Upgraded(implementation);
  }

  /**
  * @dev Throws if called by any account other than the owner.
  */
  modifier onlyProxyOwner() {
    require(msg.sender == proxyOwner());
    _;
  }

  /**
   * @dev Tells the address of the proxy owner
   * @return the address of the proxy owner
   */
  function proxyOwner() public view returns (address) {
    return upgradeabilityOwner();
  }

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferProxyOwnership(address newOwner) public onlyProxyOwner {
    require(newOwner != address(0));
    emit ProxyOwnershipTransferred(proxyOwner(), newOwner);
    setUpgradeabilityOwner(newOwner);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy.
   * @param implementation representing the address of the new implementation to be set.
   */
  function upgradeTo(address implementation) public onlyProxyOwner {
    _upgradeTo(implementation);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy
   * and delegatecall the new implementation for initialization.
   * @param implementation representing the address of the new implementation to be set.
   * @param data represents the msg.data to bet sent in the low level call. This parameter may include the function
   * signature of the implementation to be called with the needed payload
   */
  function upgradeToAndCall(address implementation, bytes data) payable public onlyProxyOwner {
    upgradeTo(implementation);
    require(address(this).delegatecall(data));
  }
}


contract OwnableDelegateProxy is OwnedUpgradeabilityProxy {

    constructor(address owner, address initialImplementation, bytes calldata)
        public
    {
        setUpgradeabilityOwner(owner);
        _upgradeTo(initialImplementation);
        require(initialImplementation.delegatecall(calldata));
    }

}

pragma solidity ^0.4.13;

contract Ownable {
  address public owner;


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


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  constructor() public {
    owner = msg.sender;
  }

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

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipRenounced(owner);
    owner = address(0);
  }
}

contract ERC20Basic {
  function totalSupply() public view returns (uint256);
  function balanceOf(address who) public view returns (uint256);
  function transfer(address to, uint256 value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}

contract ERC20 is ERC20Basic {
  function allowance(address owner, address spender)
    public view returns (uint256);

  function transferFrom(address from, address to, uint256 value)
    public returns (bool);

  function approve(address spender, uint256 value) public returns (bool);
  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

contract ProxyRegistry is Ownable {

    /* DelegateProxy implementation contract. Must be initialized. */
    address public delegateProxyImplementation;

    /* Authenticated proxies by user. */
    mapping(address => OwnableDelegateProxy) public proxies;

    /* Contracts pending access. */
    mapping(address => uint) public pending;

    /* Contracts allowed to call those proxies. */
    mapping(address => bool) public contracts;

    /* Delay period for adding an authenticated contract.
       This mitigates a particular class of potential attack on the Wyvern DAO (which owns this registry) - if at any point the value of assets held by proxy contracts exceeded the value of half the WYV supply (votes in the DAO),
       a malicious but rational attacker could buy half the Wyvern and grant themselves access to all the proxy contracts. A delay period renders this attack nonthreatening - given two weeks, if that happened, users would have
       plenty of time to notice and transfer their assets.
    */
    uint public DELAY_PERIOD = 2 weeks;

    /**
     * Start the process to enable access for specified contract. Subject to delay period.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address to which to grant permissions
     */
    function startGrantAuthentication (address addr)
        public
        onlyOwner
    {
        require(!contracts[addr] && pending[addr] == 0);
        pending[addr] = now;
    }

    /**
     * End the process to nable access for specified contract after delay period has passed.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address to which to grant permissions
     */
    function endGrantAuthentication (address addr)
        public
        onlyOwner
    {
        require(!contracts[addr] && pending[addr] != 0 && ((pending[addr] + DELAY_PERIOD) < now));
        pending[addr] = 0;
        contracts[addr] = true;
    }

    /**
     * Revoke access for specified contract. Can be done instantly.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address of which to revoke permissions
     */    
    function revokeAuthentication (address addr)
        public
        onlyOwner
    {
        contracts[addr] = false;
    }

    /**
     * Register a proxy contract with this registry
     *
     * @dev Must be called by the user which the proxy is for, creates a new AuthenticatedProxy
     * @return New AuthenticatedProxy contract
     */
    function registerProxy()
        public
        returns (OwnableDelegateProxy proxy)
    {
        require(proxies[msg.sender] == address(0));
        proxy = new OwnableDelegateProxy(msg.sender, delegateProxyImplementation, abi.encodeWithSignature("initialize(address,address)", msg.sender, address(this)));
        proxies[msg.sender] = proxy;
        return proxy;
    }

}

contract TokenRecipient {
    event ReceivedEther(address indexed sender, uint amount);
    event ReceivedTokens(address indexed from, uint256 value, address indexed token, bytes extraData);

    /**
     * @dev Receive tokens and generate a log event
     * @param from Address from which to transfer tokens
     * @param value Amount of tokens to transfer
     * @param token Address of token
     * @param extraData Additional data to log
     */
    function receiveApproval(address from, uint256 value, address token, bytes extraData) public {
        ERC20 t = ERC20(token);
        require(t.transferFrom(from, this, value));
        emit ReceivedTokens(from, value, token, extraData);
    }

    /**
     * @dev Receive Ether and generate a log event
     */
    function () payable public {
        emit ReceivedEther(msg.sender, msg.value);
    }
}

contract OwnedUpgradeabilityStorage {

  // Current implementation
  address internal _implementation;

  // Owner of the contract
  address private _upgradeabilityOwner;

  /**
   * @dev Tells the address of the owner
   * @return the address of the owner
   */
  function upgradeabilityOwner() public view returns (address) {
    return _upgradeabilityOwner;
  }

  /**
   * @dev Sets the address of the owner
   */
  function setUpgradeabilityOwner(address newUpgradeabilityOwner) internal {
    _upgradeabilityOwner = newUpgradeabilityOwner;
  }

  /**
  * @dev Tells the address of the current implementation
  * @return address of the current implementation
  */
  function implementation() public view returns (address) {
    return _implementation;
  }

  /**
  * @dev Tells the proxy type (EIP 897)
  * @return Proxy type, 2 for forwarding proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId) {
    return 2;
  }
}

contract AuthenticatedProxy is TokenRecipient, OwnedUpgradeabilityStorage {

    /* Whether initialized. */
    bool initialized = false;

    /* Address which owns this proxy. */
    address public user;

    /* Associated registry with contract authentication information. */
    ProxyRegistry public registry;

    /* Whether access has been revoked. */
    bool public revoked;

    /* Delegate call could be used to atomically transfer multiple assets owned by the proxy contract with one order. */
    enum HowToCall { Call, DelegateCall }

    /* Event fired when the proxy access is revoked or unrevoked. */
    event Revoked(bool revoked);

    /**
     * Initialize an AuthenticatedProxy
     *
     * @param addrUser Address of user on whose behalf this proxy will act
     * @param addrRegistry Address of ProxyRegistry contract which will manage this proxy
     */
    function initialize (address addrUser, ProxyRegistry addrRegistry)
        public
    {
        require(!initialized);
        initialized = true;
        user = addrUser;
        registry = addrRegistry;
    }

    /**
     * Set the revoked flag (allows a user to revoke ProxyRegistry access)
     *
     * @dev Can be called by the user only
     * @param revoke Whether or not to revoke access
     */
    function setRevoke(bool revoke)
        public
    {
        require(msg.sender == user);
        revoked = revoke;
        emit Revoked(revoke);
    }

    /**
     * Execute a message call from the proxy contract
     *
     * @dev Can be called by the user, or by a contract authorized by the registry as long as the user has not revoked access
     * @param dest Address to which the call will be sent
     * @param howToCall Which kind of call to make
     * @param calldata Calldata to send
     * @return Result of the call (success or failure)
     */
    function proxy(address dest, HowToCall howToCall, bytes calldata)
        public
        returns (bool result)
    {
        require(msg.sender == user || (!revoked && registry.contracts(msg.sender)));
        if (howToCall == HowToCall.Call) {
            result = dest.call(calldata);
        } else if (howToCall == HowToCall.DelegateCall) {
            result = dest.delegatecall(calldata);
        }
        return result;
    }

    /**
     * Execute a message call and assert success
     * 
     * @dev Same functionality as `proxy`, just asserts the return value
     * @param dest Address to which the call will be sent
     * @param howToCall What kind of call to make
     * @param calldata Calldata to send
     */
    function proxyAssert(address dest, HowToCall howToCall, bytes calldata)
        public
    {
        require(proxy(dest, howToCall, calldata));
    }

}

contract Proxy {

  /**
  * @dev Tells the address of the implementation where every call will be delegated.
  * @return address of the implementation to which it will be delegated
  */
  function implementation() public view returns (address);

  /**
  * @dev Tells the type of proxy (EIP 897)
  * @return Type of proxy, 2 for upgradeable proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId);

  /**
  * @dev Fallback function allowing to perform a delegatecall to the given implementation.
  * This function will return whatever the implementation call returns
  */
  function () payable public {
    address _impl = implementation();
    require(_impl != address(0));

    assembly {
      let ptr := mload(0x40)
      calldatacopy(ptr, 0, calldatasize)
      let result := delegatecall(gas, _impl, ptr, calldatasize, 0, 0)
      let size := returndatasize
      returndatacopy(ptr, 0, size)

      switch result
      case 0 { revert(ptr, size) }
      default { return(ptr, size) }
    }
  }
}

contract OwnedUpgradeabilityProxy is Proxy, OwnedUpgradeabilityStorage {
  /**
  * @dev Event to show ownership has been transferred
  * @param previousOwner representing the address of the previous owner
  * @param newOwner representing the address of the new owner
  */
  event ProxyOwnershipTransferred(address previousOwner, address newOwner);

  /**
  * @dev This event will be emitted every time the implementation gets upgraded
  * @param implementation representing the address of the upgraded implementation
  */
  event Upgraded(address indexed implementation);

  /**
  * @dev Upgrades the implementation address
  * @param implementation representing the address of the new implementation to be set
  */
  function _upgradeTo(address implementation) internal {
    require(_implementation != implementation);
    _implementation = implementation;
    emit Upgraded(implementation);
  }

  /**
  * @dev Throws if called by any account other than the owner.
  */
  modifier onlyProxyOwner() {
    require(msg.sender == proxyOwner());
    _;
  }

  /**
   * @dev Tells the address of the proxy owner
   * @return the address of the proxy owner
   */
  function proxyOwner() public view returns (address) {
    return upgradeabilityOwner();
  }

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferProxyOwnership(address newOwner) public onlyProxyOwner {
    require(newOwner != address(0));
    emit ProxyOwnershipTransferred(proxyOwner(), newOwner);
    setUpgradeabilityOwner(newOwner);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy.
   * @param implementation representing the address of the new implementation to be set.
   */
  function upgradeTo(address implementation) public onlyProxyOwner {
    _upgradeTo(implementation);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy
   * and delegatecall the new implementation for initialization.
   * @param implementation representing the address of the new implementation to be set.
   * @param data represents the msg.data to bet sent in the low level call. This parameter may include the function
   * signature of the implementation to be called with the needed payload
   */
  function upgradeToAndCall(address implementation, bytes data) payable public onlyProxyOwner {
    upgradeTo(implementation);
    require(address(this).delegatecall(data));
  }
}

contract OwnableDelegateProxy is OwnedUpgradeabilityProxy {

    constructor(address owner, address initialImplementation, bytes calldata)
        public
    {
        setUpgradeabilityOwner(owner);
        _upgradeTo(initialImplementation);
        require(initialImplementation.delegatecall(calldata));
    }

}

pragma solidity 0.8.11;

interface IERC721 {
    function safeTransferFrom(address from, address to, uint256 tokenId) external;
    function transferFrom(address from, address to, uint256 tokenId) external;
}

interface IERC1155 {
    function safeTransferFrom(address from, address to, uint256 tokenId, uint256 amount, bytes calldata data) external;
}

/// @title MerkleValidator enables matching trait-based and collection-based orders for ERC721 and ERC1155 tokens.
/// @author 0age
/// @dev This contract is intended to be called during atomicMatch_ via DELEGATECALL.
contract MerkleValidator {
    /// @dev InvalidProof is thrown on invalid proofs.
    error InvalidProof();

    /// @dev UnnecessaryProof is thrown in cases where a proof is supplied without a valid root to match against (root = 0)
    error UnnecessaryProof();

    /// @dev Match an ERC721 order, ensuring that the supplied proof demonstrates inclusion of the tokenId in the associated merkle root.
    /// @param from The account to transfer the ERC721 token from — this token must first be approved on the seller's AuthenticatedProxy contract.
    /// @param to The account to transfer the ERC721 token to.
    /// @param token The ERC721 token to transfer.
    /// @param tokenId The ERC721 tokenId to transfer.
    /// @param root A merkle root derived from each valid tokenId — set to 0 to indicate a collection-level or tokenId-specific order.
    /// @param proof A proof that the supplied tokenId is contained within the associated merkle root. Must be length 0 if root is not set.
    /// @return A boolean indicating a successful match and transfer.
    function matchERC721UsingCriteria(
        address from,
        address to,
        IERC721 token,
        uint256 tokenId,
        bytes32 root,
        bytes32[] calldata proof
    ) external returns (bool) {
    	// Proof verification is performed when there's a non-zero root.
    	if (root != bytes32(0)) {
    		_verifyProof(tokenId, root, proof);
    	} else if (proof.length != 0) {
    		// A root of zero should never have a proof.
    		revert UnnecessaryProof();
    	}

    	// Transfer the token.
        token.transferFrom(from, to, tokenId);

        return true;
    }

    /// @dev Match an ERC721 order using `safeTransferFrom`, ensuring that the supplied proof demonstrates inclusion of the tokenId in the associated merkle root.
    /// @param from The account to transfer the ERC721 token from — this token must first be approved on the seller's AuthenticatedProxy contract.
    /// @param to The account to transfer the ERC721 token to.
    /// @param token The ERC721 token to transfer.
    /// @param tokenId The ERC721 tokenId to transfer.
    /// @param root A merkle root derived from each valid tokenId — set to 0 to indicate a collection-level or tokenId-specific order.
    /// @param proof A proof that the supplied tokenId is contained within the associated merkle root. Must be length 0 if root is not set.
    /// @return A boolean indicating a successful match and transfer.
    function matchERC721WithSafeTransferUsingCriteria(
        address from,
        address to,
        IERC721 token,
        uint256 tokenId,
        bytes32 root,
        bytes32[] calldata proof
    ) external returns (bool) {
        // Proof verification is performed when there's a non-zero root.
        if (root != bytes32(0)) {
            _verifyProof(tokenId, root, proof);
        } else if (proof.length != 0) {
            // A root of zero should never have a proof.
            revert UnnecessaryProof();
        }

        // Transfer the token.
        token.safeTransferFrom(from, to, tokenId);

        return true;
    }

    /// @dev Match an ERC1155 order, ensuring that the supplied proof demonstrates inclusion of the tokenId in the associated merkle root.
    /// @param from The account to transfer the ERC1155 token from — this token must first be approved on the seller's AuthenticatedProxy contract.
    /// @param to The account to transfer the ERC1155 token to.
    /// @param token The ERC1155 token to transfer.
    /// @param tokenId The ERC1155 tokenId to transfer.
    /// @param amount The amount of ERC1155 tokens with the given tokenId to transfer.
    /// @param root A merkle root derived from each valid tokenId — set to 0 to indicate a collection-level or tokenId-specific order.
    /// @param proof A proof that the supplied tokenId is contained within the associated merkle root. Must be length 0 if root is not set.
    /// @return A boolean indicating a successful match and transfer.
    function matchERC1155UsingCriteria(
        address from,
        address to,
        IERC1155 token,
        uint256 tokenId,
        uint256 amount,
        bytes32 root,
        bytes32[] calldata proof
    ) external returns (bool) {
        // Proof verification is performed when there's a non-zero root.
        if (root != bytes32(0)) {
            _verifyProof(tokenId, root, proof);
        } else if (proof.length != 0) {
            // A root of zero should never have a proof.
            revert UnnecessaryProof();
        }

        // Transfer the token.
        token.safeTransferFrom(from, to, tokenId, amount, "");

        return true;
    }

    /// @dev Ensure that a given tokenId is contained within a supplied merkle root using a supplied proof.
    /// @param leaf The tokenId.
    /// @param root A merkle root derived from each valid tokenId.
    /// @param proof A proof that the supplied tokenId is contained within the associated merkle root.
    function _verifyProof(
        uint256 leaf,
        bytes32 root,
        bytes32[] memory proof
    ) private pure {
        bytes32 computedHash = bytes32(leaf);
        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];
            if (computedHash <= proofElement) {
                // Hash(current computed hash + current element of the proof)
                computedHash = _efficientHash(computedHash, proofElement);
            } else {
                // Hash(current element of the proof + current computed hash)
                computedHash = _efficientHash(proofElement, computedHash);
            }
        }
        if (computedHash != root) {
            revert InvalidProof();
        }
    }

    /// @dev Efficiently hash two bytes32 elements using memory scratch space.
    /// @param a The first element included in the hash.
    /// @param b The second element included in the hash.
    /// @return value The resultant hash of the two bytes32 elements.
    function _efficientHash(
        bytes32 a,
        bytes32 b
    ) private pure returns (bytes32 value) {
        assembly {
            mstore(0x00, a)
            mstore(0x20, b)
            value := keccak256(0x00, 0x40)
        }
    }
}

// SPDX-License-Identifier: MIT

// File: @openzeppelin/contracts/utils/math/SafeMath.sol

// OpenZeppelin Contracts v4.4.1 (utils/math/SafeMath.sol)

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b)
        internal
        pure
        returns (bool, uint256)
    {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b)
        internal
        pure
        returns (bool, uint256)
    {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b)
        internal
        pure
        returns (bool, uint256)
    {
        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.
     *
     * _Available since v3.4._
     */
    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.
     *
     * _Available since v3.4._
     */
    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 addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

// File: @openzeppelin/contracts/utils/structs/EnumerableSet.sol

// OpenZeppelin Contracts v4.4.1 (utils/structs/EnumerableSet.sol)

pragma solidity ^0.8.0;

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping(bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) {
            // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            if (lastIndex != toDeleteIndex) {
                bytes32 lastvalue = set._values[lastIndex];

                // Move the last value to the index where the value to delete is
                set._values[toDeleteIndex] = lastvalue;
                // Update the index for the moved value
                set._indexes[lastvalue] = valueIndex; // Replace lastvalue's index to valueIndex
            }

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value)
        private
        view
        returns (bool)
    {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function _at(Set storage set, uint256 index)
        private
        view
        returns (bytes32)
    {
        return set._values[index];
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function _values(Set storage set) private view returns (bytes32[] memory) {
        return set._values;
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value)
        internal
        returns (bool)
    {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value)
        internal
        returns (bool)
    {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value)
        internal
        view
        returns (bool)
    {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(Bytes32Set storage set, uint256 index)
        internal
        view
        returns (bytes32)
    {
        return _at(set._inner, index);
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(Bytes32Set storage set)
        internal
        view
        returns (bytes32[] memory)
    {
        return _values(set._inner);
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value)
        internal
        returns (bool)
    {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value)
        internal
        returns (bool)
    {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value)
        internal
        view
        returns (bool)
    {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(AddressSet storage set, uint256 index)
        internal
        view
        returns (address)
    {
        return address(uint160(uint256(_at(set._inner, index))));
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(AddressSet storage set)
        internal
        view
        returns (address[] memory)
    {
        bytes32[] memory store = _values(set._inner);
        address[] memory result;

        assembly {
            result := store
        }

        return result;
    }

    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value)
        internal
        returns (bool)
    {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value)
        internal
        view
        returns (bool)
    {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(UintSet storage set, uint256 index)
        internal
        view
        returns (uint256)
    {
        return uint256(_at(set._inner, index));
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(UintSet storage set)
        internal
        view
        returns (uint256[] memory)
    {
        bytes32[] memory store = _values(set._inner);
        uint256[] memory result;

        assembly {
            result := store
        }

        return result;
    }
}

// File: @openzeppelin/contracts/utils/introspection/IERC165.sol

// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @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);
}

// File: @openzeppelin/contracts/utils/introspection/ERC165.sol

// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override
        returns (bool)
    {
        return interfaceId == type(IERC165).interfaceId;
    }
}

// File: @openzeppelin/contracts/utils/Strings.sol

// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length)
        internal
        pure
        returns (string memory)
    {
        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_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}

// File: @openzeppelin/contracts/access/IAccessControl.sol

// OpenZeppelin Contracts v4.4.1 (access/IAccessControl.sol)

pragma solidity ^0.8.0;

/**
 * @dev External interface of AccessControl declared to support ERC165 detection.
 */
interface IAccessControl {
    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(
        bytes32 indexed role,
        bytes32 indexed previousAdminRole,
        bytes32 indexed newAdminRole
    );

    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {AccessControl-_setupRole}.
     */
    event RoleGranted(
        bytes32 indexed role,
        address indexed account,
        address indexed sender
    );

    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(
        bytes32 indexed role,
        address indexed account,
        address indexed sender
    );

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account)
        external
        view
        returns (bool);

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {AccessControl-_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) external view returns (bytes32);

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) external;

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) external;

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) external;
}

// File: @openzeppelin/contracts/access/IAccessControlEnumerable.sol

// OpenZeppelin Contracts v4.4.1 (access/IAccessControlEnumerable.sol)

pragma solidity ^0.8.0;

/**
 * @dev External interface of AccessControlEnumerable declared to support ERC165 detection.
 */
interface IAccessControlEnumerable is IAccessControl {
    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index)
        external
        view
        returns (address);

    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) external view returns (uint256);
}

// File: @openzeppelin/contracts/utils/Context.sol

// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with 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;
    }
}

// File: @openzeppelin/contracts/access/AccessControl.sol

// OpenZeppelin Contracts (last updated v4.5.0) (access/AccessControl.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms. This is a lightweight version that doesn't allow enumerating role
 * members except through off-chain means by accessing the contract event logs. Some
 * applications may benefit from on-chain enumerability, for those cases see
 * {AccessControlEnumerable}.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context, IAccessControl, ERC165 {
    struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
    }

    mapping(bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /**
     * @dev Modifier that checks that an account has a specific role. Reverts
     * with a standardized message including the required role.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     *
     * _Available since v4.1._
     */
    modifier onlyRole(bytes32 role) {
        _checkRole(role, _msgSender());
        _;
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override
        returns (bool)
    {
        return
            interfaceId == type(IAccessControl).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account)
        public
        view
        virtual
        override
        returns (bool)
    {
        return _roles[role].members[account];
    }

    /**
     * @dev Revert with a standard message if `account` is missing `role`.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     */
    function _checkRole(bytes32 role, address account) internal view virtual {
        if (!hasRole(role, account)) {
            revert(
                string(
                    abi.encodePacked(
                        "AccessControl: account ",
                        Strings.toHexString(uint160(account), 20),
                        " is missing role ",
                        Strings.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role)
        public
        view
        virtual
        override
        returns (bytes32)
    {
        return _roles[role].adminRole;
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account)
        public
        virtual
        override
        onlyRole(getRoleAdmin(role))
    {
        _grantRole(role, account);
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account)
        public
        virtual
        override
        onlyRole(getRoleAdmin(role))
    {
        _revokeRole(role, account);
    }

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been revoked `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account)
        public
        virtual
        override
    {
        require(
            account == _msgSender(),
            "AccessControl: can only renounce roles for self"
        );

        _revokeRole(role, account);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     *
     * NOTE: This function is deprecated in favor of {_grantRole}.
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }

    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        bytes32 previousAdminRole = getRoleAdmin(role);
        _roles[role].adminRole = adminRole;
        emit RoleAdminChanged(role, previousAdminRole, adminRole);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * Internal function without access restriction.
     */
    function _grantRole(bytes32 role, address account) internal virtual {
        if (!hasRole(role, account)) {
            _roles[role].members[account] = true;
            emit RoleGranted(role, account, _msgSender());
        }
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * Internal function without access restriction.
     */
    function _revokeRole(bytes32 role, address account) internal virtual {
        if (hasRole(role, account)) {
            _roles[role].members[account] = false;
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}

// File: @openzeppelin/contracts/access/AccessControlEnumerable.sol

// OpenZeppelin Contracts (last updated v4.5.0) (access/AccessControlEnumerable.sol)

pragma solidity ^0.8.0;

/**
 * @dev Extension of {AccessControl} that allows enumerating the members of each role.
 */
abstract contract AccessControlEnumerable is
    IAccessControlEnumerable,
    AccessControl
{
    using EnumerableSet for EnumerableSet.AddressSet;

    mapping(bytes32 => EnumerableSet.AddressSet) private _roleMembers;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override
        returns (bool)
    {
        return
            interfaceId == type(IAccessControlEnumerable).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index)
        public
        view
        virtual
        override
        returns (address)
    {
        return _roleMembers[role].at(index);
    }

    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role)
        public
        view
        virtual
        override
        returns (uint256)
    {
        return _roleMembers[role].length();
    }

    /**
     * @dev Overload {_grantRole} to track enumerable memberships
     */
    function _grantRole(bytes32 role, address account)
        internal
        virtual
        override
    {
        super._grantRole(role, account);
        _roleMembers[role].add(account);
    }

    /**
     * @dev Overload {_revokeRole} to track enumerable memberships
     */
    function _revokeRole(bytes32 role, address account)
        internal
        virtual
        override
    {
        super._revokeRole(role, account);
        _roleMembers[role].remove(account);
    }
}

// File: @openzeppelin/contracts/security/Pausable.sol

// OpenZeppelin Contracts v4.4.1 (security/Pausable.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract Pausable is Context {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    constructor() {
        _paused = false;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        require(!paused(), "Pausable: paused");
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        require(paused(), "Pausable: not paused");
        _;
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol

// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

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

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

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

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

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

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

// File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol

// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
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);
}

// File: @openzeppelin/contracts/token/ERC20/ERC20.sol

// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * The default value of {decimals} is 18. To select a different value for
     * {decimals} you should overload it.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless this function is
     * overridden;
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account)
        public
        view
        virtual
        override
        returns (uint256)
    {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address to, uint256 amount)
        public
        virtual
        override
        returns (bool)
    {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender)
        public
        view
        virtual
        override
        returns (uint256)
    {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount)
        public
        virtual
        override
        returns (bool)
    {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue)
        public
        virtual
        returns (bool)
    {
        address owner = _msgSender();
        _approve(owner, spender, _allowances[owner][spender] + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue)
        public
        virtual
        returns (bool)
    {
        address owner = _msgSender();
        uint256 currentAllowance = _allowances[owner][spender];
        require(
            currentAllowance >= subtractedValue,
            "ERC20: decreased allowance below zero"
        );
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `sender` to `recipient`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     */
    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(
            fromBalance >= amount,
            "ERC20: transfer amount exceeds balance"
        );
        unchecked {
            _balances[from] = fromBalance - amount;
        }
        _balances[to] += amount;

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
        }
        _totalSupply -= amount;

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Spend `amount` form the allowance of `owner` toward `spender`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    function _spendAllowance(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(
                currentAllowance >= amount,
                "ERC20: insufficient allowance"
            );
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

// File: @openzeppelin/contracts/token/ERC20/extensions/ERC20Pausable.sol

// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/ERC20Pausable.sol)

pragma solidity ^0.8.0;

/**
 * @dev ERC20 token with pausable token transfers, minting and burning.
 *
 * Useful for scenarios such as preventing trades until the end of an evaluation
 * period, or having an emergency switch for freezing all token transfers in the
 * event of a large bug.
 */
abstract contract ERC20Pausable is ERC20, Pausable {
    /**
     * @dev See {ERC20-_beforeTokenTransfer}.
     *
     * Requirements:
     *
     * - the contract must not be paused.
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual override {
        super._beforeTokenTransfer(from, to, amount);

        require(!paused(), "ERC20Pausable: token transfer while paused");
    }
}

// File: @openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol

// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/extensions/ERC20Burnable.sol)

pragma solidity ^0.8.0;

/**
 * @dev Extension of {ERC20} that allows token holders to destroy both their own
 * tokens and those that they have an allowance for, in a way that can be
 * recognized off-chain (via event analysis).
 */
abstract contract ERC20Burnable is Context, ERC20 {
    /**
     * @dev Destroys `amount` tokens from the caller.
     *
     * See {ERC20-_burn}.
     */
    function burn(uint256 amount) public virtual {
        _burn(_msgSender(), amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, deducting from the caller's
     * allowance.
     *
     * See {ERC20-_burn} and {ERC20-allowance}.
     *
     * Requirements:
     *
     * - the caller must have allowance for ``accounts``'s tokens of at least
     * `amount`.
     */
    function burnFrom(address account, uint256 amount) public virtual {
        _spendAllowance(account, _msgSender(), amount);
        _burn(account, amount);
    }
}

// File: @openzeppelin/contracts/token/ERC20/presets/ERC20PresetMinterPauser.sol

// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/presets/ERC20PresetMinterPauser.sol)

pragma solidity ^0.8.0;

/**
 * @dev {ERC20} token, including:
 *
 *  - ability for holders to burn (destroy) their tokens
 *  - a minter role that allows for token minting (creation)
 *  - a pauser role that allows to stop all token transfers
 *
 * This contract uses {AccessControl} to lock permissioned functions using the
 * different roles - head to its documentation for details.
 *
 * The account that deploys the contract will be granted the minter and pauser
 * roles, as well as the default admin role, which will let it grant both minter
 * and pauser roles to other accounts.
 *
 * _Deprecated in favor of https://wizard.openzeppelin.com/[Contracts Wizard]._
 */
contract ERC20PresetMinterPauser is
    Context,
    AccessControlEnumerable,
    ERC20Burnable,
    ERC20Pausable
{
    bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
    bytes32 public constant PAUSER_ROLE = keccak256("PAUSER_ROLE");

    /**
     * @dev Grants `DEFAULT_ADMIN_ROLE`, `MINTER_ROLE` and `PAUSER_ROLE` to the
     * account that deploys the contract.
     *
     * See {ERC20-constructor}.
     */
    constructor(string memory name, string memory symbol) ERC20(name, symbol) {
        _setupRole(DEFAULT_ADMIN_ROLE, _msgSender());

        _setupRole(MINTER_ROLE, _msgSender());
        _setupRole(PAUSER_ROLE, _msgSender());
    }

    /**
     * @dev Creates `amount` new tokens for `to`.
     *
     * See {ERC20-_mint}.
     *
     * Requirements:
     *
     * - the caller must have the `MINTER_ROLE`.
     */
    function mint(address to, uint256 amount) public virtual {
        require(
            hasRole(MINTER_ROLE, _msgSender()),
            "ERC20PresetMinterPauser: must have minter role to mint"
        );
        _mint(to, amount);
    }

    /**
     * @dev Pauses all token transfers.
     *
     * See {ERC20Pausable} and {Pausable-_pause}.
     *
     * Requirements:
     *
     * - the caller must have the `PAUSER_ROLE`.
     */
    function pause() public virtual {
        require(
            hasRole(PAUSER_ROLE, _msgSender()),
            "ERC20PresetMinterPauser: must have pauser role to pause"
        );
        _pause();
    }

    /**
     * @dev Unpauses all token transfers.
     *
     * See {ERC20Pausable} and {Pausable-_unpause}.
     *
     * Requirements:
     *
     * - the caller must have the `PAUSER_ROLE`.
     */
    function unpause() public virtual {
        require(
            hasRole(PAUSER_ROLE, _msgSender()),
            "ERC20PresetMinterPauser: must have pauser role to unpause"
        );
        _unpause();
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual override(ERC20, ERC20Pausable) {
        super._beforeTokenTransfer(from, to, amount);
    }
}

// File: contracts/StarToken.sol

pragma solidity >=0.8.0 <0.9.0;

interface INFTContract {
    function balanceOf(address _user) external view returns (uint256);
}

contract StarToken is ERC20PresetMinterPauser {
    using SafeMath for uint256;

    INFTContract public nftContract;

    uint256 public constant INITIAL_REWARD = 100 ether;
    uint256 public constant REWARD_RATE = 10 ether;
    uint256 public constant SECONDARY_REWARD_RATE = 5 ether;
    // Monday, April 1, 2032 0:00:00
    uint256 public constant REWARD_END = 1964390400;

    mapping(address => uint256) public rewards;
    mapping(address => uint256) public lastUpdate;
    mapping(address => INFTContract) public secondaryContracts;
    address[] public secondaryContractsAddresses;

    event StarClaimed(address indexed account, uint256 reward);
    event StarSpent(address indexed account, uint256 amount);

    bytes32 public constant BURNER_ROLE = keccak256("BURNER_ROLE");

    constructor(address _nftContract)
        ERC20PresetMinterPauser("Star Token", "STAR")
    {
        grantRole(BURNER_ROLE, msg.sender);
        setContract(_nftContract);
    }

    function setContract(address _contract) public {
        require(hasRole(DEFAULT_ADMIN_ROLE, _msgSender()), "Admin only");
        nftContract = INFTContract(_contract);
        grantRole(BURNER_ROLE, _contract);
    }

    function addSecondaryContract(address _contract) public {
        require(hasRole(DEFAULT_ADMIN_ROLE, _msgSender()), "Admin only");
        secondaryContracts[_contract] = INFTContract(_contract);
        secondaryContractsAddresses.push(_contract);
        grantRole(BURNER_ROLE, _contract);
    }

    function removeSecondaryContract(address _contract) public {
        require(hasRole(DEFAULT_ADMIN_ROLE, _msgSender()), "Admin only");
        delete secondaryContracts[_contract];
        uint256 index = 0;
        while (secondaryContractsAddresses[index] != _contract) {
            index++;
        }
        secondaryContractsAddresses[index] = secondaryContractsAddresses[
            secondaryContractsAddresses.length - 1
        ];
        secondaryContractsAddresses.pop();
        revokeRole(BURNER_ROLE, _contract);
    }

    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    function updateRewardOnMint(address _to, uint256 _amount) external {
        require(msg.sender == address(nftContract), "Not allowed");
        uint256 time = min(block.timestamp, REWARD_END);
        uint256 timerUser = lastUpdate[_to];
        if (timerUser > 0)
            rewards[_to] = rewards[_to].add(
                nftContract
                    .balanceOf(_to)
                    .mul(REWARD_RATE.mul((time.sub(timerUser))))
                    .div(86400)
                    .add(_amount.mul(INITIAL_REWARD))
            );
        else rewards[_to] = rewards[_to].add(_amount.mul(INITIAL_REWARD));
        lastUpdate[_to] = time;
    }

    function updateReward(address _from, address _to) external {
        require(
            msg.sender == address(nftContract) ||
                abi.encodePacked(secondaryContracts[msg.sender]).length > 0,
            "Invalid Contract"
        );
        uint256 time = min(block.timestamp, REWARD_END);
        if (_from != address(0)) {
            uint256 timerFrom = lastUpdate[_from];
            if (timerFrom > 0) {
                rewards[_from] += getPendingReward(_from);
            }
            lastUpdate[_from] = lastUpdate[_from] < REWARD_END
                ? time
                : REWARD_END;
        }

        if (_to != address(0)) {
            uint256 timerTo = lastUpdate[_to];
            if (timerTo > 0) {
                rewards[_to] += getPendingReward(_to);
            }
            lastUpdate[_to] = lastUpdate[_to] < REWARD_END ? time : REWARD_END;
        }
    }

    function getReward(address _to) external {
        require(msg.sender == address(nftContract), "Not allowed");
        uint256 reward = rewards[_to];
        if (reward > 0) {
            rewards[_to] = 0;
            _mint(_to, reward);
            emit StarClaimed(_to, reward);
        }
    }

    function getTotalClaimable(address _account)
        external
        view
        returns (uint256)
    {
        return rewards[_account] + getPendingReward(_account);
    }

    function getPendingReward(address _account)
        internal
        view
        returns (uint256)
    {
        uint256 time = min(block.timestamp, REWARD_END);
        uint256 secondary = 0;
        if (secondaryContractsAddresses.length > 0) {
            for (uint256 i = 0; i < secondaryContractsAddresses.length; i++) {
                secondary = secondaryContracts[secondaryContractsAddresses[i]]
                    .balanceOf(_account)
                    .mul(
                        SECONDARY_REWARD_RATE.mul(
                            (time.sub(lastUpdate[_account]))
                        )
                    )
                    .div(86400)
                    .add(secondary);
            }
        }

        return
            nftContract
                .balanceOf(_account)
                .mul(REWARD_RATE.mul((time.sub(lastUpdate[_account]))))
                .div(86400)
                .add(secondary);
    }

    function burn(uint256 value) public override {
        require(
            hasRole(BURNER_ROLE, msg.sender),
            "Must have burner role to burn"
        );
        super._burn(msg.sender, value);
    }

    function spend(address _from, uint256 _amount) external {
        require(
            hasRole(BURNER_ROLE, msg.sender),
            "Must have burner role to spend"
        );
        super._burn(_from, _amount);
        emit StarSpent(_from, _amount);
    }
}