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
pragma solidity ^0.8.0;
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC1155/ERC1155.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/token/ERC1155/extensions/ERC1155Supply.sol";
import "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
struct ProducerPass {
    uint256 price;
    uint256 episodeId;
    uint256 maxSupply;
    uint256 maxPerWallet;
    uint256 openMintTimestamp; // unix timestamp in seconds
    bytes32 merkleRoot;
}
contract WhiteRabbitProducerPass is ERC1155, ERC1155Supply, Ownable {
    using Strings for uint256;
    // The name of the token ("White Rabbit Producer Pass")
    string public name;
    // The token symbol ("WRPP")
    string public symbol;
    // The wallet addresses of the two artists creating the film
    address payable private artistAddress1;
    address payable private artistAddress2;
    // The wallet addresses of the three developers managing the film
    address payable private devAddress1;
    address payable private devAddress2;
    address payable private devAddress3;
    // The royalty percentages for the artists and developers
    uint256 private constant ARTIST_ROYALTY_PERCENTAGE = 60;
    uint256 private constant DEV_ROYALTY_PERCENTAGE = 40;
    // A mapping of the number of Producer Passes minted per episodeId per user
    // userPassesMintedPerTokenId[msg.sender][episodeId] => number of minted passes
    mapping(address => mapping(uint256 => uint256))
        private userPassesMintedPerTokenId;
    // A mapping from episodeId to its Producer Pass
    mapping(uint256 => ProducerPass) private episodeToProducerPass;
    // Event emitted when a Producer Pass is bought
    event ProducerPassBought(
        uint256 episodeId,
        address indexed account,
        uint256 amount
    );
    /**
     * @dev Initializes the contract by setting the name and the token symbol
     */
    constructor(string memory baseURI) ERC1155(baseURI) {
        name = "White Rabbit Producer Pass";
        symbol = "WRPP";
    }
    /**
     * @dev Checks if the provided Merkle Proof is valid for the given root hash.
     */
    function isValidMerkleProof(bytes32[] calldata merkleProof, bytes32 root)
        internal
        view
        returns (bool)
    {
        return
            MerkleProof.verify(
                merkleProof,
                root,
                keccak256(abi.encodePacked(msg.sender))
            );
    }
    /**
     * @dev Retrieves the Producer Pass for a given episode.
     */
    function getEpisodeToProducerPass(uint256 episodeId)
        external
        view
        returns (ProducerPass memory)
    {
        return episodeToProducerPass[episodeId];
    }
    /**
     * @dev Contracts the metadata URI for the Producer Pass of the given episodeId.
     *
     * Requirements:
     *
     * - The Producer Pass exists for the given episode
     */
    function uri(uint256 episodeId)
        public
        view
        override
        returns (string memory)
    {
        require(
            episodeToProducerPass[episodeId].episodeId != 0,
            "Invalid episode"
        );
        return
            string(
                abi.encodePacked(
                    super.uri(episodeId),
                    episodeId.toString(),
                    ".json"
                )
            );
    }
    /**
     * Owner-only methods
     */
    /**
     * @dev Sets the base URI for the Producer Pass metadata.
     */
    function setBaseURI(string memory baseURI) external onlyOwner {
        _setURI(baseURI);
    }
    /**
     * @dev Sets the parameters on the Producer Pass struct for the given episode.
     */
    function setProducerPass(
        uint256 price,
        uint256 episodeId,
        uint256 maxSupply,
        uint256 maxPerWallet,
        uint256 openMintTimestamp,
        bytes32 merkleRoot
    ) external onlyOwner {
        episodeToProducerPass[episodeId] = ProducerPass(
            price,
            episodeId,
            maxSupply,
            maxPerWallet,
            openMintTimestamp,
            merkleRoot
        );
    }
    /**
     * @dev Withdraws the balance and distributes it to the artists and developers
     * based on the `ARTIST_ROYALTY_PERCENTAGE` and `DEV_ROYALTY_PERCENTAGE`.
     */
    function withdraw() external onlyOwner {
        uint256 balance = address(this).balance;
        uint256 artistBalance = (balance * ARTIST_ROYALTY_PERCENTAGE) / 100;
        uint256 balancePerArtist = artistBalance / 2;
        uint256 devBalance = (balance * DEV_ROYALTY_PERCENTAGE) / 100;
        uint256 balancePerDev = devBalance / 3;
        bool success;
        // Transfer artist balances
        (success, ) = artistAddress1.call{value: balancePerArtist}("");
        require(success, "Withdraw unsuccessful");
        (success, ) = artistAddress2.call{value: balancePerArtist}("");
        require(success, "Withdraw unsuccessful");
        // Transfer dev balances
        (success, ) = devAddress1.call{value: balancePerDev}("");
        require(success, "Withdraw unsuccessful");
        (success, ) = devAddress2.call{value: balancePerDev}("");
        require(success, "Withdraw unsuccessful");
        (success, ) = devAddress3.call{value: balancePerDev}("");
        require(success, "Withdraw unsuccessful");
    }
    /**
     * @dev Sets the royalty addresses for the two artists and three developers.
     */
    function setRoyaltyAddresses(
        address _a1,
        address _a2,
        address _d1,
        address _d2,
        address _d3
    ) external onlyOwner {
        artistAddress1 = payable(_a1);
        artistAddress2 = payable(_a2);
        devAddress1 = payable(_d1);
        devAddress2 = payable(_d2);
        devAddress3 = payable(_d3);
    }
    /**
     * @dev Creates a reserve of Producer Passes to set aside for gifting.
     *
     * Requirements:
     *
     * - There are enough Producer Passes to mint for the given episode
     * - The supply for the given episode does not exceed the maxSupply of the Producer Pass
     */
    function reserveProducerPassesForGifting(
        uint256 episodeId,
        uint256 amountEachAddress,
        address[] calldata addresses
    ) public onlyOwner {
        ProducerPass memory pass = episodeToProducerPass[episodeId];
        require(amountEachAddress > 0, "Amount cannot be 0");
        require(totalSupply(episodeId) < pass.maxSupply, "No passes to mint");
        require(
            totalSupply(episodeId) + amountEachAddress * addresses.length <=
                pass.maxSupply,
            "Cannot mint that many"
        );
        require(addresses.length > 0, "Need addresses");
        for (uint256 i = 0; i < addresses.length; i++) {
            address add = addresses[i];
            _mint(add, episodeId, amountEachAddress, "");
        }
    }
    /**
     * @dev Mints a set number of Producer Passes for a given episode.
     *
     * Emits a `ProducerPassBought` event indicating the Producer Pass was minted successfully.
     *
     * Requirements:
     *
     * - The current time is within the minting window for the given episode
     * - There are Producer Passes available to mint for the given episode
     * - The user is not trying to mint more than the maxSupply
     * - The user is not trying to mint more than the maxPerWallet
     * - The user has enough ETH for the transaction
     */
    function mintProducerPass(uint256 episodeId, uint256 amount)
        external
        payable
    {
        ProducerPass memory pass = episodeToProducerPass[episodeId];
        require(
            block.timestamp >= pass.openMintTimestamp,
            "Mint is not available"
        );
        require(totalSupply(episodeId) < pass.maxSupply, "Sold out");
        require(
            totalSupply(episodeId) + amount <= pass.maxSupply,
            "Cannot mint that many"
        );
        uint256 totalMintedPasses = userPassesMintedPerTokenId[msg.sender][
            episodeId
        ];
        require(
            totalMintedPasses + amount <= pass.maxPerWallet,
            "Exceeding maximum per wallet"
        );
        require(msg.value == pass.price * amount, "Not enough eth");
        userPassesMintedPerTokenId[msg.sender][episodeId] =
            totalMintedPasses +
            amount;
        _mint(msg.sender, episodeId, amount, "");
        emit ProducerPassBought(episodeId, msg.sender, amount);
    }
    /**
     * @dev For those on with early access (on the whitelist),
     * mints a set number of Producer Passes for a given episode.
     *
     * Emits a `ProducerPassBought` event indicating the Producer Pass was minted successfully.
     *
     * Requirements:
     *
     * - Provides a valid Merkle proof, indicating the user is on the whitelist
     * - There are Producer Passes available to mint for the given episode
     * - The user is not trying to mint more than the maxSupply
     * - The user is not trying to mint more than the maxPerWallet
     * - The user has enough ETH for the transaction
     */
    function earlyMintProducerPass(
        uint256 episodeId,
        uint256 amount,
        bytes32[] calldata merkleProof
    ) external payable {
        ProducerPass memory pass = episodeToProducerPass[episodeId];
        require(
            isValidMerkleProof(merkleProof, pass.merkleRoot),
            "Not authorized to mint"
        );
        require(totalSupply(episodeId) < pass.maxSupply, "Sold out");
        require(
            totalSupply(episodeId) + amount <= pass.maxSupply,
            "Cannot mint that many"
        );
        uint256 totalMintedPasses = userPassesMintedPerTokenId[msg.sender][
            episodeId
        ];
        require(
            totalMintedPasses + amount <= pass.maxPerWallet,
            "Exceeding maximum per wallet"
        );
        require(msg.value == pass.price * amount, "Not enough eth");
        userPassesMintedPerTokenId[msg.sender][episodeId] =
            totalMintedPasses +
            amount;
        _mint(msg.sender, episodeId, amount, "");
        emit ProducerPassBought(episodeId, msg.sender, amount);
    }
    /**
     * @dev Retrieves the number of Producer Passes a user has minted by episodeId.
     */
    function userPassesMintedByEpisodeId(uint256 episodeId)
        external
        view
        returns (uint256)
    {
        return userPassesMintedPerTokenId[msg.sender][episodeId];
    }
    /**
     * @dev Boilerplate override for `_beforeTokenTransfer`
     */
    function _beforeTokenTransfer(
        address operator,
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) internal virtual override(ERC1155, ERC1155Supply) {
        super._beforeTokenTransfer(operator, from, to, ids, amounts, data);
    }
}
// SPDX-License-Identifier: MIT
// 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);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _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);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC1155/ERC1155.sol)
pragma solidity ^0.8.0;
import "./IERC1155.sol";
import "./IERC1155Receiver.sol";
import "./extensions/IERC1155MetadataURI.sol";
import "../../utils/Address.sol";
import "../../utils/Context.sol";
import "../../utils/introspection/ERC165.sol";
/**
 * @dev Implementation of the basic standard multi-token.
 * See https://eips.ethereum.org/EIPS/eip-1155
 * Originally based on code by Enjin: https://github.com/enjin/erc-1155
 *
 * _Available since v3.1._
 */
contract ERC1155 is Context, ERC165, IERC1155, IERC1155MetadataURI {
    using Address for address;
    // Mapping from token ID to account balances
    mapping(uint256 => mapping(address => uint256)) private _balances;
    // Mapping from account to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;
    // Used as the URI for all token types by relying on ID substitution, e.g. https://token-cdn-domain/{id}.json
    string private _uri;
    /**
     * @dev See {_setURI}.
     */
    constructor(string memory uri_) {
        _setURI(uri_);
    }
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC1155).interfaceId ||
            interfaceId == type(IERC1155MetadataURI).interfaceId ||
            super.supportsInterface(interfaceId);
    }
    /**
     * @dev See {IERC1155MetadataURI-uri}.
     *
     * This implementation returns the same URI for *all* token types. It relies
     * on the token type ID substitution mechanism
     * https://eips.ethereum.org/EIPS/eip-1155#metadata[defined in the EIP].
     *
     * Clients calling this function must replace the `\\{id\\}` substring with the
     * actual token type ID.
     */
    function uri(uint256) public view virtual override returns (string memory) {
        return _uri;
    }
    /**
     * @dev See {IERC1155-balanceOf}.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function balanceOf(address account, uint256 id) public view virtual override returns (uint256) {
        require(account != address(0), "ERC1155: balance query for the zero address");
        return _balances[id][account];
    }
    /**
     * @dev See {IERC1155-balanceOfBatch}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(address[] memory accounts, uint256[] memory ids)
        public
        view
        virtual
        override
        returns (uint256[] memory)
    {
        require(accounts.length == ids.length, "ERC1155: accounts and ids length mismatch");
        uint256[] memory batchBalances = new uint256[](accounts.length);
        for (uint256 i = 0; i < accounts.length; ++i) {
            batchBalances[i] = balanceOf(accounts[i], ids[i]);
        }
        return batchBalances;
    }
    /**
     * @dev See {IERC1155-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        _setApprovalForAll(_msgSender(), operator, approved);
    }
    /**
     * @dev See {IERC1155-isApprovedForAll}.
     */
    function isApprovedForAll(address account, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[account][operator];
    }
    /**
     * @dev See {IERC1155-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes memory data
    ) public virtual override {
        require(
            from == _msgSender() || isApprovedForAll(from, _msgSender()),
            "ERC1155: caller is not owner nor approved"
        );
        _safeTransferFrom(from, to, id, amount, data);
    }
    /**
     * @dev See {IERC1155-safeBatchTransferFrom}.
     */
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) public virtual override {
        require(
            from == _msgSender() || isApprovedForAll(from, _msgSender()),
            "ERC1155: transfer caller is not owner nor approved"
        );
        _safeBatchTransferFrom(from, to, ids, amounts, data);
    }
    /**
     * @dev Transfers `amount` tokens of token type `id` from `from` to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `from` must have a balance of tokens of type `id` of at least `amount`.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function _safeTransferFrom(
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes memory data
    ) internal virtual {
        require(to != address(0), "ERC1155: transfer to the zero address");
        address operator = _msgSender();
        _beforeTokenTransfer(operator, from, to, _asSingletonArray(id), _asSingletonArray(amount), data);
        uint256 fromBalance = _balances[id][from];
        require(fromBalance >= amount, "ERC1155: insufficient balance for transfer");
        unchecked {
            _balances[id][from] = fromBalance - amount;
        }
        _balances[id][to] += amount;
        emit TransferSingle(operator, from, to, id, amount);
        _doSafeTransferAcceptanceCheck(operator, from, to, id, amount, data);
    }
    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {_safeTransferFrom}.
     *
     * Emits a {TransferBatch} event.
     *
     * Requirements:
     *
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function _safeBatchTransferFrom(
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) internal virtual {
        require(ids.length == amounts.length, "ERC1155: ids and amounts length mismatch");
        require(to != address(0), "ERC1155: transfer to the zero address");
        address operator = _msgSender();
        _beforeTokenTransfer(operator, from, to, ids, amounts, data);
        for (uint256 i = 0; i < ids.length; ++i) {
            uint256 id = ids[i];
            uint256 amount = amounts[i];
            uint256 fromBalance = _balances[id][from];
            require(fromBalance >= amount, "ERC1155: insufficient balance for transfer");
            unchecked {
                _balances[id][from] = fromBalance - amount;
            }
            _balances[id][to] += amount;
        }
        emit TransferBatch(operator, from, to, ids, amounts);
        _doSafeBatchTransferAcceptanceCheck(operator, from, to, ids, amounts, data);
    }
    /**
     * @dev Sets a new URI for all token types, by relying on the token type ID
     * substitution mechanism
     * https://eips.ethereum.org/EIPS/eip-1155#metadata[defined in the EIP].
     *
     * By this mechanism, any occurrence of the `\\{id\\}` substring in either the
     * URI or any of the amounts in the JSON file at said URI will be replaced by
     * clients with the token type ID.
     *
     * For example, the `https://token-cdn-domain/\\{id\\}.json` URI would be
     * interpreted by clients as
     * `https://token-cdn-domain/000000000000000000000000000000000000000000000000000000000004cce0.json`
     * for token type ID 0x4cce0.
     *
     * See {uri}.
     *
     * Because these URIs cannot be meaningfully represented by the {URI} event,
     * this function emits no events.
     */
    function _setURI(string memory newuri) internal virtual {
        _uri = newuri;
    }
    /**
     * @dev Creates `amount` tokens of token type `id`, and assigns them to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function _mint(
        address to,
        uint256 id,
        uint256 amount,
        bytes memory data
    ) internal virtual {
        require(to != address(0), "ERC1155: mint to the zero address");
        address operator = _msgSender();
        _beforeTokenTransfer(operator, address(0), to, _asSingletonArray(id), _asSingletonArray(amount), data);
        _balances[id][to] += amount;
        emit TransferSingle(operator, address(0), to, id, amount);
        _doSafeTransferAcceptanceCheck(operator, address(0), to, id, amount, data);
    }
    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {_mint}.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function _mintBatch(
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) internal virtual {
        require(to != address(0), "ERC1155: mint to the zero address");
        require(ids.length == amounts.length, "ERC1155: ids and amounts length mismatch");
        address operator = _msgSender();
        _beforeTokenTransfer(operator, address(0), to, ids, amounts, data);
        for (uint256 i = 0; i < ids.length; i++) {
            _balances[ids[i]][to] += amounts[i];
        }
        emit TransferBatch(operator, address(0), to, ids, amounts);
        _doSafeBatchTransferAcceptanceCheck(operator, address(0), to, ids, amounts, data);
    }
    /**
     * @dev Destroys `amount` tokens of token type `id` from `from`
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `from` must have at least `amount` tokens of token type `id`.
     */
    function _burn(
        address from,
        uint256 id,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "ERC1155: burn from the zero address");
        address operator = _msgSender();
        _beforeTokenTransfer(operator, from, address(0), _asSingletonArray(id), _asSingletonArray(amount), "");
        uint256 fromBalance = _balances[id][from];
        require(fromBalance >= amount, "ERC1155: burn amount exceeds balance");
        unchecked {
            _balances[id][from] = fromBalance - amount;
        }
        emit TransferSingle(operator, from, address(0), id, amount);
    }
    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {_burn}.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     */
    function _burnBatch(
        address from,
        uint256[] memory ids,
        uint256[] memory amounts
    ) internal virtual {
        require(from != address(0), "ERC1155: burn from the zero address");
        require(ids.length == amounts.length, "ERC1155: ids and amounts length mismatch");
        address operator = _msgSender();
        _beforeTokenTransfer(operator, from, address(0), ids, amounts, "");
        for (uint256 i = 0; i < ids.length; i++) {
            uint256 id = ids[i];
            uint256 amount = amounts[i];
            uint256 fromBalance = _balances[id][from];
            require(fromBalance >= amount, "ERC1155: burn amount exceeds balance");
            unchecked {
                _balances[id][from] = fromBalance - amount;
            }
        }
        emit TransferBatch(operator, from, address(0), ids, amounts);
    }
    /**
     * @dev Approve `operator` to operate on all of `owner` tokens
     *
     * Emits a {ApprovalForAll} event.
     */
    function _setApprovalForAll(
        address owner,
        address operator,
        bool approved
    ) internal virtual {
        require(owner != operator, "ERC1155: setting approval status for self");
        _operatorApprovals[owner][operator] = approved;
        emit ApprovalForAll(owner, operator, approved);
    }
    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning, as well as batched variants.
     *
     * The same hook is called on both single and batched variants. For single
     * transfers, the length of the `id` and `amount` arrays will be 1.
     *
     * Calling conditions (for each `id` and `amount` pair):
     *
     * - When `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * of token type `id` will be  transferred to `to`.
     * - When `from` is zero, `amount` tokens of token type `id` will be minted
     * for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens of token type `id`
     * will be burned.
     * - `from` and `to` are never both zero.
     * - `ids` and `amounts` have the same, non-zero length.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address operator,
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) internal virtual {}
    function _doSafeTransferAcceptanceCheck(
        address operator,
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes memory data
    ) private {
        if (to.isContract()) {
            try IERC1155Receiver(to).onERC1155Received(operator, from, id, amount, data) returns (bytes4 response) {
                if (response != IERC1155Receiver.onERC1155Received.selector) {
                    revert("ERC1155: ERC1155Receiver rejected tokens");
                }
            } catch Error(string memory reason) {
                revert(reason);
            } catch {
                revert("ERC1155: transfer to non ERC1155Receiver implementer");
            }
        }
    }
    function _doSafeBatchTransferAcceptanceCheck(
        address operator,
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) private {
        if (to.isContract()) {
            try IERC1155Receiver(to).onERC1155BatchReceived(operator, from, ids, amounts, data) returns (
                bytes4 response
            ) {
                if (response != IERC1155Receiver.onERC1155BatchReceived.selector) {
                    revert("ERC1155: ERC1155Receiver rejected tokens");
                }
            } catch Error(string memory reason) {
                revert(reason);
            } catch {
                revert("ERC1155: transfer to non ERC1155Receiver implementer");
            }
        }
    }
    function _asSingletonArray(uint256 element) private pure returns (uint256[] memory) {
        uint256[] memory array = new uint256[](1);
        array[0] = element;
        return array;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)
pragma solidity ^0.8.0;
/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.
        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }
    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");
        (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);
            }
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC1155/extensions/ERC1155Supply.sol)
pragma solidity ^0.8.0;
import "../ERC1155.sol";
/**
 * @dev Extension of ERC1155 that adds tracking of total supply per id.
 *
 * Useful for scenarios where Fungible and Non-fungible tokens have to be
 * clearly identified. Note: While a totalSupply of 1 might mean the
 * corresponding is an NFT, there is no guarantees that no other token with the
 * same id are not going to be minted.
 */
abstract contract ERC1155Supply is ERC1155 {
    mapping(uint256 => uint256) private _totalSupply;
    /**
     * @dev Total amount of tokens in with a given id.
     */
    function totalSupply(uint256 id) public view virtual returns (uint256) {
        return _totalSupply[id];
    }
    /**
     * @dev Indicates whether any token exist with a given id, or not.
     */
    function exists(uint256 id) public view virtual returns (bool) {
        return ERC1155Supply.totalSupply(id) > 0;
    }
    /**
     * @dev See {ERC1155-_beforeTokenTransfer}.
     */
    function _beforeTokenTransfer(
        address operator,
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) internal virtual override {
        super._beforeTokenTransfer(operator, from, to, ids, amounts, data);
        if (from == address(0)) {
            for (uint256 i = 0; i < ids.length; ++i) {
                _totalSupply[ids[i]] += amounts[i];
            }
        }
        if (to == address(0)) {
            for (uint256 i = 0; i < ids.length; ++i) {
                _totalSupply[ids[i]] -= amounts[i];
            }
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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 = keccak256(abi.encodePacked(computedHash, proofElement));
            } else {
                // Hash(current element of the proof + current computed hash)
                computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
            }
        }
        return computedHash;
    }
}
// SPDX-License-Identifier: MIT
// 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;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC1155/IERC1155.sol)
pragma solidity ^0.8.0;
import "../../utils/introspection/IERC165.sol";
/**
 * @dev Required interface of an ERC1155 compliant contract, as defined in the
 * https://eips.ethereum.org/EIPS/eip-1155[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155 is IERC165 {
    /**
     * @dev Emitted when `value` tokens of token type `id` are transferred from `from` to `to` by `operator`.
     */
    event TransferSingle(address indexed operator, address indexed from, address indexed to, uint256 id, uint256 value);
    /**
     * @dev Equivalent to multiple {TransferSingle} events, where `operator`, `from` and `to` are the same for all
     * transfers.
     */
    event TransferBatch(
        address indexed operator,
        address indexed from,
        address indexed to,
        uint256[] ids,
        uint256[] values
    );
    /**
     * @dev Emitted when `account` grants or revokes permission to `operator` to transfer their tokens, according to
     * `approved`.
     */
    event ApprovalForAll(address indexed account, address indexed operator, bool approved);
    /**
     * @dev Emitted when the URI for token type `id` changes to `value`, if it is a non-programmatic URI.
     *
     * If an {URI} event was emitted for `id`, the standard
     * https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[guarantees] that `value` will equal the value
     * returned by {IERC1155MetadataURI-uri}.
     */
    event URI(string value, uint256 indexed id);
    /**
     * @dev Returns the amount of tokens of token type `id` owned by `account`.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function balanceOf(address account, uint256 id) external view returns (uint256);
    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {balanceOf}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(address[] calldata accounts, uint256[] calldata ids)
        external
        view
        returns (uint256[] memory);
    /**
     * @dev Grants or revokes permission to `operator` to transfer the caller's tokens, according to `approved`,
     *
     * Emits an {ApprovalForAll} event.
     *
     * Requirements:
     *
     * - `operator` cannot be the caller.
     */
    function setApprovalForAll(address operator, bool approved) external;
    /**
     * @dev Returns true if `operator` is approved to transfer ``account``'s tokens.
     *
     * See {setApprovalForAll}.
     */
    function isApprovedForAll(address account, address operator) external view returns (bool);
    /**
     * @dev Transfers `amount` tokens of token type `id` from `from` to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - If the caller is not `from`, it must be have been approved to spend ``from``'s tokens via {setApprovalForAll}.
     * - `from` must have a balance of tokens of type `id` of at least `amount`.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes calldata data
    ) external;
    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {safeTransferFrom}.
     *
     * Emits a {TransferBatch} event.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] calldata ids,
        uint256[] calldata amounts,
        bytes calldata data
    ) external;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC1155/IERC1155Receiver.sol)
pragma solidity ^0.8.0;
import "../../utils/introspection/IERC165.sol";
/**
 * @dev _Available since v3.1._
 */
interface IERC1155Receiver is IERC165 {
    /**
        @dev Handles the receipt of a single ERC1155 token type. This function is
        called at the end of a `safeTransferFrom` after the balance has been updated.
        To accept the transfer, this must return
        `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))`
        (i.e. 0xf23a6e61, or its own function selector).
        @param operator The address which initiated the transfer (i.e. msg.sender)
        @param from The address which previously owned the token
        @param id The ID of the token being transferred
        @param value The amount of tokens being transferred
        @param data Additional data with no specified format
        @return `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))` if transfer is allowed
    */
    function onERC1155Received(
        address operator,
        address from,
        uint256 id,
        uint256 value,
        bytes calldata data
    ) external returns (bytes4);
    /**
        @dev Handles the receipt of a multiple ERC1155 token types. This function
        is called at the end of a `safeBatchTransferFrom` after the balances have
        been updated. To accept the transfer(s), this must return
        `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))`
        (i.e. 0xbc197c81, or its own function selector).
        @param operator The address which initiated the batch transfer (i.e. msg.sender)
        @param from The address which previously owned the token
        @param ids An array containing ids of each token being transferred (order and length must match values array)
        @param values An array containing amounts of each token being transferred (order and length must match ids array)
        @param data Additional data with no specified format
        @return `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))` if transfer is allowed
    */
    function onERC1155BatchReceived(
        address operator,
        address from,
        uint256[] calldata ids,
        uint256[] calldata values,
        bytes calldata data
    ) external returns (bytes4);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC1155/extensions/IERC1155MetadataURI.sol)
pragma solidity ^0.8.0;
import "../IERC1155.sol";
/**
 * @dev Interface of the optional ERC1155MetadataExtension interface, as defined
 * in the https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155MetadataURI is IERC1155 {
    /**
     * @dev Returns the URI for token type `id`.
     *
     * If the `\\{id\\}` substring is present in the URI, it must be replaced by
     * clients with the actual token type ID.
     */
    function uri(uint256 id) external view returns (string memory);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)
pragma solidity ^0.8.0;
import "./IERC165.sol";
/**
 * @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;
    }
}
// SPDX-License-Identifier: MIT
// 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);
}

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)
        }
    }
}