A full decompilation and automatic security analysis of all contracts on the Ethereum and the Fantom blockchains. Updated hourly with new contracts uploaded to both networks. Analysis results by Dedaub.

Contract Library for the Ethereum and Fantom blockchains by Dedaub

offerer

zone

offer

consideration

orderType

startTime

endTime

zoneHash

salt

conduitKey

counter

orders

cancel

cancelled

parameters

numerator

denominator

signature

extraData

advancedOrder

orderIndex

side

index

identifier

criteriaProof

criteriaResolvers

fulfillerConduitKey

recipient

fulfillAdvancedOrder

fulfilled

advancedOrders

itemIndex

offerFulfillments

considerationFulfillments

maximumFulfilled

fulfillAvailableAdvancedOrders

availableOrders

item

executions

fulfillAvailableOrders

considerationToken

considerationIdentifier

considerationAmount

offerToken

offerIdentifier

offerAmount

basicOrderType

offererConduitKey

totalOriginalAdditionalRecipients

additionalRecipients

fulfillBasicOrder

order

fulfillOrder

getCounter

getOrderHash

orderHash

getOrderStatus

isValidated

isCancelled

totalFilled

totalSize

incrementCounter

newCounter

information

version

domainSeparator

conduitController

offerComponents

considerationComponents

fulfillments

matchAdvancedOrders

matchOrders

name

contractName

validate

validated

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

/**
 * @title AmountDerivationErrors
 * @author 0age
 * @notice AmountDerivationErrors contains errors related to amount derivation.
 */
interface AmountDerivationErrors {
    /**
     * @dev Revert with an error when attempting to apply a fraction as part of
     *      a partial fill that does not divide the target amount cleanly.
     */
    error InexactFraction();
}

AmountDerivationErrors.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.13;

// prettier-ignore
import {
    AmountDerivationErrors
} from "AmountDerivationErrors.sol";

import "ConsiderationConstants.sol";

/**
 * @title AmountDeriver
 * @author 0age
 * @notice AmountDeriver contains view and pure functions related to deriving
 *         item amounts based on partial fill quantity and on linear
 *         interpolation based on current time when the start amount and end
 *         amount differ.
 */
contract AmountDeriver is AmountDerivationErrors {
    /**
     * @dev Internal view function to derive the current amount of a given item
     *      based on the current price, the starting price, and the ending
     *      price. If the start and end prices differ, the current price will be
     *      interpolated on a linear basis. Note that this function expects that
     *      the startTime parameter of orderParameters is not greater than the
     *      current block timestamp and that the endTime parameter is greater
     *      than the current block timestamp. If this condition is not upheld,
     *      duration / elapsed / remaining variables will underflow.
     *
     * @param startAmount The starting amount of the item.
     * @param endAmount   The ending amount of the item.
     * @param startTime   The starting time of the order.
     * @param endTime     The end time of the order.
     * @param roundUp     A boolean indicating whether the resultant amount
     *                    should be rounded up or down.
     *
     * @return amount The current amount.
     */
    function _locateCurrentAmount(
        uint256 startAmount,
        uint256 endAmount,
        uint256 startTime,
        uint256 endTime,
        bool roundUp
    ) internal view returns (uint256 amount) {
        // Only modify end amount if it doesn't already equal start amount.
        if (startAmount != endAmount) {
            // Declare variables to derive in the subsequent unchecked scope.
            uint256 duration;
            uint256 elapsed;
            uint256 remaining;

            // Skip underflow checks as startTime <= block.timestamp < endTime.
            unchecked {
                // Derive the duration for the order and place it on the stack.
                duration = endTime - startTime;

                // Derive time elapsed since the order started & place on stack.
                elapsed = block.timestamp - startTime;

                // Derive time remaining until order expires and place on stack.
                remaining = duration - elapsed;
            }

            // Aggregate new amounts weighted by time with rounding factor.
            uint256 totalBeforeDivision = ((startAmount * remaining) +
                (endAmount * elapsed));

            // Use assembly to combine operations and skip divide-by-zero check.
            assembly {
                // Multiply by iszero(iszero(totalBeforeDivision)) to ensure
                // amount is set to zero if totalBeforeDivision is zero,
                // as intermediate overflow can occur if it is zero.
                amount := mul(
                    iszero(iszero(totalBeforeDivision)),
                    // Subtract 1 from the numerator and add 1 to the result if
                    // roundUp is true to get the proper rounding direction.
                    // Division is performed with no zero check as duration
                    // cannot be zero as long as startTime < endTime.
                    add(
                        div(sub(totalBeforeDivision, roundUp), duration),
                        roundUp
                    )
                )
            }

            // Return the current amount.
            return amount;
        }

        // Return the original amount as startAmount == endAmount.
        return endAmount;
    }

    /**
     * @dev Internal pure function to return a fraction of a given value and to
     *      ensure the resultant value does not have any fractional component.
     *      Note that this function assumes that zero will never be supplied as
     *      the denominator parameter; invalid / undefined behavior will result
     *      should a denominator of zero be provided.
     *
     * @param numerator   A value indicating the portion of the order that
     *                    should be filled.
     * @param denominator A value indicating the total size of the order. Note
     *                    that this value cannot be equal to zero.
     * @param value       The value for which to compute the fraction.
     *
     * @return newValue The value after applying the fraction.
     */
    function _getFraction(
        uint256 numerator,
        uint256 denominator,
        uint256 value
    ) internal pure returns (uint256 newValue) {
        // Return value early in cases where the fraction resolves to 1.
        if (numerator == denominator) {
            return value;
        }

        // Ensure fraction can be applied to the value with no remainder. Note
        // that the denominator cannot be zero.
        assembly {
            // Ensure new value contains no remainder via mulmod operator.
            // Credit to @hrkrshnn + @axic for proposing this optimal solution.
            if mulmod(value, numerator, denominator) {
                mstore(0, InexactFraction_error_signature)
                revert(0, InexactFraction_error_len)
            }
        }

        // Multiply the numerator by the value and ensure no overflow occurs.
        uint256 valueTimesNumerator = value * numerator;

        // Divide and check for remainder. Note that denominator cannot be zero.
        assembly {
            // Perform division without zero check.
            newValue := div(valueTimesNumerator, denominator)
        }
    }

    /**
     * @dev Internal view function to apply a fraction to a consideration
     * or offer item.
     *
     * @param startAmount     The starting amount of the item.
     * @param endAmount       The ending amount of the item.
     * @param numerator       A value indicating the portion of the order that
     *                        should be filled.
     * @param denominator     A value indicating the total size of the order.
     * @param startTime       The starting time of the order.
     * @param endTime         The end time of the order.
     * @param roundUp         A boolean indicating whether the resultant
     *                        amount should be rounded up or down.
     *
     * @return amount The received item to transfer with the final amount.
     */
    function _applyFraction(
        uint256 startAmount,
        uint256 endAmount,
        uint256 numerator,
        uint256 denominator,
        uint256 startTime,
        uint256 endTime,
        bool roundUp
    ) internal view returns (uint256 amount) {
        // If start amount equals end amount, apply fraction to end amount.
        if (startAmount == endAmount) {
            // Apply fraction to end amount.
            amount = _getFraction(numerator, denominator, endAmount);
        } else {
            // Otherwise, apply fraction to both and interpolated final amount.
            amount = _locateCurrentAmount(
                _getFraction(numerator, denominator, startAmount),
                _getFraction(numerator, denominator, endAmount),
                startTime,
                endTime,
                roundUp
            );
        }
    }
}

AmountDeriver.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.13;

import { OrderParameters } from "ConsiderationStructs.sol";

import { GettersAndDerivers } from "GettersAndDerivers.sol";

// prettier-ignore
import {
    TokenTransferrerErrors
} from "TokenTransferrerErrors.sol";

import { CounterManager } from "CounterManager.sol";

import "ConsiderationConstants.sol";

/**
 * @title Assertions
 * @author 0age
 * @notice Assertions contains logic for making various assertions that do not
 *         fit neatly within a dedicated semantic scope.
 */
contract Assertions is
    GettersAndDerivers,
    CounterManager,
    TokenTransferrerErrors
{
    /**
     * @dev Derive and set hashes, reference chainId, and associated domain
     *      separator during deployment.
     *
     * @param conduitController A contract that deploys conduits, or proxies
     *                          that may optionally be used to transfer approved
     *                          ERC20/721/1155 tokens.
     */
    constructor(address conduitController)
        GettersAndDerivers(conduitController)
    {}

    /**
     * @dev Internal view function to ensure that the supplied consideration
     *      array length on a given set of order parameters is not less than the
     *      original consideration array length for that order and to retrieve
     *      the current counter for a given order's offerer and zone and use it
     *      to derive the order hash.
     *
     * @param orderParameters The parameters of the order to hash.
     *
     * @return The hash.
     */
    function _assertConsiderationLengthAndGetOrderHash(
        OrderParameters memory orderParameters
    ) internal view returns (bytes32) {
        // Ensure supplied consideration array length is not less than original.
        _assertConsiderationLengthIsNotLessThanOriginalConsiderationLength(
            orderParameters.consideration.length,
            orderParameters.totalOriginalConsiderationItems
        );

        // Derive and return order hash using current counter for the offerer.
        return
            _deriveOrderHash(
                orderParameters,
                _getCounter(orderParameters.offerer)
            );
    }

    /**
     * @dev Internal pure function to ensure that the supplied consideration
     *      array length for an order to be fulfilled is not less than the
     *      original consideration array length for that order.
     *
     * @param suppliedConsiderationItemTotal The number of consideration items
     *                                       supplied when fulfilling the order.
     * @param originalConsiderationItemTotal The number of consideration items
     *                                       supplied on initial order creation.
     */
    function _assertConsiderationLengthIsNotLessThanOriginalConsiderationLength(
        uint256 suppliedConsiderationItemTotal,
        uint256 originalConsiderationItemTotal
    ) internal pure {
        // Ensure supplied consideration array length is not less than original.
        if (suppliedConsiderationItemTotal < originalConsiderationItemTotal) {
            revert MissingOriginalConsiderationItems();
        }
    }

    /**
     * @dev Internal pure function to ensure that a given item amount is not
     *      zero.
     *
     * @param amount The amount to check.
     */
    function _assertNonZeroAmount(uint256 amount) internal pure {
        // Revert if the supplied amount is equal to zero.
        if (amount == 0) {
            revert MissingItemAmount();
        }
    }

    /**
     * @dev Internal pure function to validate calldata offsets for dynamic
     *      types in BasicOrderParameters and other parameters. This ensures
     *      that functions using the calldata object normally will be using the
     *      same data as the assembly functions and that values that are bound
     *      to a given range are within that range. Note that no parameters are
     *      supplied as all basic order functions use the same calldata
     *      encoding.
     */
    function _assertValidBasicOrderParameters() internal pure {
        // Declare a boolean designating basic order parameter offset validity.
        bool validOffsets;

        // Utilize assembly in order to read offset data directly from calldata.
        assembly {
            /*
             * Checks:
             * 1. Order parameters struct offset == 0x20
             * 2. Additional recipients arr offset == 0x240
             * 3. Signature offset == 0x260 + (recipients.length * 0x40)
             * 4. BasicOrderType between 0 and 23 (i.e. < 24)
             */
            validOffsets := and(
                // Order parameters at calldata 0x04 must have offset of 0x20.
                eq(
                    calldataload(BasicOrder_parameters_cdPtr),
                    BasicOrder_parameters_ptr
                ),
                // Additional recipients at cd 0x224 must have offset of 0x240.
                eq(
                    calldataload(BasicOrder_additionalRecipients_head_cdPtr),
                    BasicOrder_additionalRecipients_head_ptr
                )
            )

            validOffsets := and(
                validOffsets,
                eq(
                    // Load signature offset from calldata 0x244.
                    calldataload(BasicOrder_signature_cdPtr),
                    // Derive expected offset as start of recipients + len * 64.
                    add(
                        BasicOrder_signature_ptr,
                        mul(
                            // Additional recipients length at calldata 0x264.
                            calldataload(
                                BasicOrder_additionalRecipients_length_cdPtr
                            ),
                            // Each additional recipient has a length of 0x40.
                            AdditionalRecipients_size
                        )
                    )
                )
            )

            validOffsets := and(
                validOffsets,
                lt(
                    // BasicOrderType parameter at calldata offset 0x124.
                    calldataload(BasicOrder_basicOrderType_cdPtr),
                    // Value should be less than 24.
                    BasicOrder_basicOrderType_range
                )
            )
        }

        // Revert with an error if basic order parameter offsets are invalid.
        if (!validOffsets) {
            revert InvalidBasicOrderParameterEncoding();
        }
    }
}

Assertions.sol

BasicOrderFulfiller.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

import { ConduitInterface } from "ConduitInterface.sol";

import { ConduitItemType } from "ConduitEnums.sol";

import { TokenTransferrer } from "TokenTransferrer.sol";

// prettier-ignore
import {
    ConduitTransfer,
    ConduitBatch1155Transfer
} from "ConduitStructs.sol";

import "ConduitConstants.sol";

/**
 * @title Conduit
 * @author 0age
 * @notice This contract serves as an originator for "proxied" transfers. Each
 *         conduit is deployed and controlled by a "conduit controller" that can
 *         add and remove "channels" or contracts that can instruct the conduit
 *         to transfer approved ERC20/721/1155 tokens. *IMPORTANT NOTE: each
 *         conduit has an owner that can arbitrarily add or remove channels, and
 *         a malicious or negligent owner can add a channel that allows for any
 *         approved ERC20/721/1155 tokens to be taken immediately — be extremely
 *         cautious with what conduits you give token approvals to!*
 */
contract Conduit is ConduitInterface, TokenTransferrer {
    // Set deployer as an immutable controller that can update channel statuses.
    address private immutable _controller;

    // Track the status of each channel.
    mapping(address => bool) private _channels;

    /**
     * @notice Ensure that the caller is currently registered as an open channel
     *         on the conduit.
     */
    modifier onlyOpenChannel() {
        // Utilize assembly to access channel storage mapping directly.
        assembly {
            // Write the caller to scratch space.
            mstore(ChannelKey_channel_ptr, caller())

            // Write the storage slot for _channels to scratch space.
            mstore(ChannelKey_slot_ptr, _channels.slot)

            // Derive the position in storage of _channels[msg.sender]
            // and check if the stored value is zero.
            if iszero(
                sload(keccak256(ChannelKey_channel_ptr, ChannelKey_length))
            ) {
                // The caller is not an open channel; revert with
                // ChannelClosed(caller). First, set error signature in memory.
                mstore(ChannelClosed_error_ptr, ChannelClosed_error_signature)

                // Next, set the caller as the argument.
                mstore(ChannelClosed_channel_ptr, caller())

                // Finally, revert, returning full custom error with argument.
                revert(ChannelClosed_error_ptr, ChannelClosed_error_length)
            }
        }

        // Continue with function execution.
        _;
    }

    /**
     * @notice In the constructor, set the deployer as the controller.
     */
    constructor() {
        // Set the deployer as the controller.
        _controller = msg.sender;
    }

    /**
     * @notice Execute a sequence of ERC20/721/1155 transfers. Only a caller
     *         with an open channel can call this function. Note that channels
     *         are expected to implement reentrancy protection if desired, and
     *         that cross-channel reentrancy may be possible if the conduit has
     *         multiple open channels at once. Also note that channels are
     *         expected to implement checks against transferring any zero-amount
     *         items if that constraint is desired.
     *
     * @param transfers The ERC20/721/1155 transfers to perform.
     *
     * @return magicValue A magic value indicating that the transfers were
     *                    performed successfully.
     */
    function execute(ConduitTransfer[] calldata transfers)
        external
        override
        onlyOpenChannel
        returns (bytes4 magicValue)
    {
        // Retrieve the total number of transfers and place on the stack.
        uint256 totalStandardTransfers = transfers.length;

        // Iterate over each transfer.
        for (uint256 i = 0; i < totalStandardTransfers; ) {
            // Retrieve the transfer in question and perform the transfer.
            _transfer(transfers[i]);

            // Skip overflow check as for loop is indexed starting at zero.
            unchecked {
                ++i;
            }
        }

        // Return a magic value indicating that the transfers were performed.
        magicValue = this.execute.selector;
    }

    /**
     * @notice Execute a sequence of batch 1155 item transfers. Only a caller
     *         with an open channel can call this function. Note that channels
     *         are expected to implement reentrancy protection if desired, and
     *         that cross-channel reentrancy may be possible if the conduit has
     *         multiple open channels at once. Also note that channels are
     *         expected to implement checks against transferring any zero-amount
     *         items if that constraint is desired.
     *
     * @param batchTransfers The 1155 batch item transfers to perform.
     *
     * @return magicValue A magic value indicating that the item transfers were
     *                    performed successfully.
     */
    function executeBatch1155(
        ConduitBatch1155Transfer[] calldata batchTransfers
    ) external override onlyOpenChannel returns (bytes4 magicValue) {
        // Perform 1155 batch transfers. Note that memory should be considered
        // entirely corrupted from this point forward.
        _performERC1155BatchTransfers(batchTransfers);

        // Return a magic value indicating that the transfers were performed.
        magicValue = this.executeBatch1155.selector;
    }

    /**
     * @notice Execute a sequence of transfers, both single ERC20/721/1155 item
     *         transfers as well as batch 1155 item transfers. Only a caller
     *         with an open channel can call this function. Note that channels
     *         are expected to implement reentrancy protection if desired, and
     *         that cross-channel reentrancy may be possible if the conduit has
     *         multiple open channels at once. Also note that channels are
     *         expected to implement checks against transferring any zero-amount
     *         items if that constraint is desired.
     *
     * @param standardTransfers The ERC20/721/1155 item transfers to perform.
     * @param batchTransfers    The 1155 batch item transfers to perform.
     *
     * @return magicValue A magic value indicating that the item transfers were
     *                    performed successfully.
     */
    function executeWithBatch1155(
        ConduitTransfer[] calldata standardTransfers,
        ConduitBatch1155Transfer[] calldata batchTransfers
    ) external override onlyOpenChannel returns (bytes4 magicValue) {
        // Retrieve the total number of transfers and place on the stack.
        uint256 totalStandardTransfers = standardTransfers.length;

        // Iterate over each standard transfer.
        for (uint256 i = 0; i < totalStandardTransfers; ) {
            // Retrieve the transfer in question and perform the transfer.
            _transfer(standardTransfers[i]);

            // Skip overflow check as for loop is indexed starting at zero.
            unchecked {
                ++i;
            }
        }

        // Perform 1155 batch transfers. Note that memory should be considered
        // entirely corrupted from this point forward aside from the free memory
        // pointer having the default value.
        _performERC1155BatchTransfers(batchTransfers);

        // Return a magic value indicating that the transfers were performed.
        magicValue = this.executeWithBatch1155.selector;
    }

    /**
     * @notice Open or close a given channel. Only callable by the controller.
     *
     * @param channel The channel to open or close.
     * @param isOpen  The status of the channel (either open or closed).
     */
    function updateChannel(address channel, bool isOpen) external override {
        // Ensure that the caller is the controller of this contract.
        if (msg.sender != _controller) {
            revert InvalidController();
        }

        // Ensure that the channel does not already have the indicated status.
        if (_channels[channel] == isOpen) {
            revert ChannelStatusAlreadySet(channel, isOpen);
        }

        // Update the status of the channel.
        _channels[channel] = isOpen;

        // Emit a corresponding event.
        emit ChannelUpdated(channel, isOpen);
    }

    /**
     * @dev Internal function to transfer a given ERC20/721/1155 item. Note that
     *      channels are expected to implement checks against transferring any
     *      zero-amount items if that constraint is desired.
     *
     * @param item The ERC20/721/1155 item to transfer.
     */
    function _transfer(ConduitTransfer calldata item) internal {
        // Determine the transfer method based on the respective item type.
        if (item.itemType == ConduitItemType.ERC20) {
            // Transfer ERC20 token. Note that item.identifier is ignored and
            // therefore ERC20 transfer items are potentially malleable — this
            // check should be performed by the calling channel if a constraint
            // on item malleability is desired.
            _performERC20Transfer(item.token, item.from, item.to, item.amount);
        } else if (item.itemType == ConduitItemType.ERC721) {
            // Ensure that exactly one 721 item is being transferred.
            if (item.amount != 1) {
                revert InvalidERC721TransferAmount();
            }

            // Transfer ERC721 token.
            _performERC721Transfer(
                item.token,
                item.from,
                item.to,
                item.identifier
            );
        } else if (item.itemType == ConduitItemType.ERC1155) {
            // Transfer ERC1155 token.
            _performERC1155Transfer(
                item.token,
                item.from,
                item.to,
                item.identifier,
                item.amount
            );
        } else {
            // Throw with an error.
            revert InvalidItemType();
        }
    }
}

Conduit.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

// error ChannelClosed(address channel)
uint256 constant ChannelClosed_error_signature = (
    0x93daadf200000000000000000000000000000000000000000000000000000000
);
uint256 constant ChannelClosed_error_ptr = 0x00;
uint256 constant ChannelClosed_channel_ptr = 0x4;
uint256 constant ChannelClosed_error_length = 0x24;

// For the mapping:
// mapping(address => bool) channels
// The position in storage for a particular account is:
// keccak256(abi.encode(account, channels.slot))
uint256 constant ChannelKey_channel_ptr = 0x00;
uint256 constant ChannelKey_slot_ptr = 0x20;
uint256 constant ChannelKey_length = 0x40;

ConduitConstants.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

/**
 * @title ConduitControllerInterface
 * @author 0age
 * @notice ConduitControllerInterface contains all external function interfaces,
 *         structs, events, and errors for the conduit controller.
 */
interface ConduitControllerInterface {
    /**
     * @dev Track the conduit key, current owner, new potential owner, and open
     *      channels for each deployed conduit.
     */
    struct ConduitProperties {
        bytes32 key;
        address owner;
        address potentialOwner;
        address[] channels;
        mapping(address => uint256) channelIndexesPlusOne;
    }

    /**
     * @dev Emit an event whenever a new conduit is created.
     *
     * @param conduit    The newly created conduit.
     * @param conduitKey The conduit key used to create the new conduit.
     */
    event NewConduit(address conduit, bytes32 conduitKey);

    /**
     * @dev Emit an event whenever conduit ownership is transferred.
     *
     * @param conduit       The conduit for which ownership has been
     *                      transferred.
     * @param previousOwner The previous owner of the conduit.
     * @param newOwner      The new owner of the conduit.
     */
    event OwnershipTransferred(
        address indexed conduit,
        address indexed previousOwner,
        address indexed newOwner
    );

    /**
     * @dev Emit an event whenever a conduit owner registers a new potential
     *      owner for that conduit.
     *
     * @param newPotentialOwner The new potential owner of the conduit.
     */
    event PotentialOwnerUpdated(address indexed newPotentialOwner);

    /**
     * @dev Revert with an error when attempting to create a new conduit using a
     *      conduit key where the first twenty bytes of the key do not match the
     *      address of the caller.
     */
    error InvalidCreator();

    /**
     * @dev Revert with an error when attempting to create a new conduit when no
     *      initial owner address is supplied.
     */
    error InvalidInitialOwner();

    /**
     * @dev Revert with an error when attempting to set a new potential owner
     *      that is already set.
     */
    error NewPotentialOwnerAlreadySet(
        address conduit,
        address newPotentialOwner
    );

    /**
     * @dev Revert with an error when attempting to cancel ownership transfer
     *      when no new potential owner is currently set.
     */
    error NoPotentialOwnerCurrentlySet(address conduit);

    /**
     * @dev Revert with an error when attempting to interact with a conduit that
     *      does not yet exist.
     */
    error NoConduit();

    /**
     * @dev Revert with an error when attempting to create a conduit that
     *      already exists.
     */
    error ConduitAlreadyExists(address conduit);

    /**
     * @dev Revert with an error when attempting to update channels or transfer
     *      ownership of a conduit when the caller is not the owner of the
     *      conduit in question.
     */
    error CallerIsNotOwner(address conduit);

    /**
     * @dev Revert with an error when attempting to register a new potential
     *      owner and supplying the null address.
     */
    error NewPotentialOwnerIsZeroAddress(address conduit);

    /**
     * @dev Revert with an error when attempting to claim ownership of a conduit
     *      with a caller that is not the current potential owner for the
     *      conduit in question.
     */
    error CallerIsNotNewPotentialOwner(address conduit);

    /**
     * @dev Revert with an error when attempting to retrieve a channel using an
     *      index that is out of range.
     */
    error ChannelOutOfRange(address conduit);

    /**
     * @notice Deploy a new conduit using a supplied conduit key and assigning
     *         an initial owner for the deployed conduit. Note that the first
     *         twenty bytes of the supplied conduit key must match the caller
     *         and that a new conduit cannot be created if one has already been
     *         deployed using the same conduit key.
     *
     * @param conduitKey   The conduit key used to deploy the conduit. Note that
     *                     the first twenty bytes of the conduit key must match
     *                     the caller of this contract.
     * @param initialOwner The initial owner to set for the new conduit.
     *
     * @return conduit The address of the newly deployed conduit.
     */
    function createConduit(bytes32 conduitKey, address initialOwner)
        external
        returns (address conduit);

    /**
     * @notice Open or close a channel on a given conduit, thereby allowing the
     *         specified account to execute transfers against that conduit.
     *         Extreme care must be taken when updating channels, as malicious
     *         or vulnerable channels can transfer any ERC20, ERC721 and ERC1155
     *         tokens where the token holder has granted the conduit approval.
     *         Only the owner of the conduit in question may call this function.
     *
     * @param conduit The conduit for which to open or close the channel.
     * @param channel The channel to open or close on the conduit.
     * @param isOpen  A boolean indicating whether to open or close the channel.
     */
    function updateChannel(
        address conduit,
        address channel,
        bool isOpen
    ) external;

    /**
     * @notice Initiate conduit ownership transfer by assigning a new potential
     *         owner for the given conduit. Once set, the new potential owner
     *         may call `acceptOwnership` to claim ownership of the conduit.
     *         Only the owner of the conduit in question may call this function.
     *
     * @param conduit The conduit for which to initiate ownership transfer.
     * @param newPotentialOwner The new potential owner of the conduit.
     */
    function transferOwnership(address conduit, address newPotentialOwner)
        external;

    /**
     * @notice Clear the currently set potential owner, if any, from a conduit.
     *         Only the owner of the conduit in question may call this function.
     *
     * @param conduit The conduit for which to cancel ownership transfer.
     */
    function cancelOwnershipTransfer(address conduit) external;

    /**
     * @notice Accept ownership of a supplied conduit. Only accounts that the
     *         current owner has set as the new potential owner may call this
     *         function.
     *
     * @param conduit The conduit for which to accept ownership.
     */
    function acceptOwnership(address conduit) external;

    /**
     * @notice Retrieve the current owner of a deployed conduit.
     *
     * @param conduit The conduit for which to retrieve the associated owner.
     *
     * @return owner The owner of the supplied conduit.
     */
    function ownerOf(address conduit) external view returns (address owner);

    /**
     * @notice Retrieve the conduit key for a deployed conduit via reverse
     *         lookup.
     *
     * @param conduit The conduit for which to retrieve the associated conduit
     *                key.
     *
     * @return conduitKey The conduit key used to deploy the supplied conduit.
     */
    function getKey(address conduit) external view returns (bytes32 conduitKey);

    /**
     * @notice Derive the conduit associated with a given conduit key and
     *         determine whether that conduit exists (i.e. whether it has been
     *         deployed).
     *
     * @param conduitKey The conduit key used to derive the conduit.
     *
     * @return conduit The derived address of the conduit.
     * @return exists  A boolean indicating whether the derived conduit has been
     *                 deployed or not.
     */
    function getConduit(bytes32 conduitKey)
        external
        view
        returns (address conduit, bool exists);

    /**
     * @notice Retrieve the potential owner, if any, for a given conduit. The
     *         current owner may set a new potential owner via
     *         `transferOwnership` and that owner may then accept ownership of
     *         the conduit in question via `acceptOwnership`.
     *
     * @param conduit The conduit for which to retrieve the potential owner.
     *
     * @return potentialOwner The potential owner, if any, for the conduit.
     */
    function getPotentialOwner(address conduit)
        external
        view
        returns (address potentialOwner);

    /**
     * @notice Retrieve the status (either open or closed) of a given channel on
     *         a conduit.
     *
     * @param conduit The conduit for which to retrieve the channel status.
     * @param channel The channel for which to retrieve the status.
     *
     * @return isOpen The status of the channel on the given conduit.
     */
    function getChannelStatus(address conduit, address channel)
        external
        view
        returns (bool isOpen);

    /**
     * @notice Retrieve the total number of open channels for a given conduit.
     *
     * @param conduit The conduit for which to retrieve the total channel count.
     *
     * @return totalChannels The total number of open channels for the conduit.
     */
    function getTotalChannels(address conduit)
        external
        view
        returns (uint256 totalChannels);

    /**
     * @notice Retrieve an open channel at a specific index for a given conduit.
     *         Note that the index of a channel can change as a result of other
     *         channels being closed on the conduit.
     *
     * @param conduit      The conduit for which to retrieve the open channel.
     * @param channelIndex The index of the channel in question.
     *
     * @return channel The open channel, if any, at the specified channel index.
     */
    function getChannel(address conduit, uint256 channelIndex)
        external
        view
        returns (address channel);

    /**
     * @notice Retrieve all open channels for a given conduit. Note that calling
     *         this function for a conduit with many channels will revert with
     *         an out-of-gas error.
     *
     * @param conduit The conduit for which to retrieve open channels.
     *
     * @return channels An array of open channels on the given conduit.
     */
    function getChannels(address conduit)
        external
        view
        returns (address[] memory channels);

    /**
     * @dev Retrieve the conduit creation code and runtime code hashes.
     */
    function getConduitCodeHashes()
        external
        view
        returns (bytes32 creationCodeHash, bytes32 runtimeCodeHash);
}

ConduitControllerInterface.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

enum ConduitItemType {
    NATIVE, // unused
    ERC20,
    ERC721,
    ERC1155
}

ConduitEnums.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

// prettier-ignore
import {
    ConduitTransfer,
    ConduitBatch1155Transfer
} from "ConduitStructs.sol";

/**
 * @title ConduitInterface
 * @author 0age
 * @notice ConduitInterface contains all external function interfaces, events,
 *         and errors for conduit contracts.
 */
interface ConduitInterface {
    /**
     * @dev Revert with an error when attempting to execute transfers using a
     *      caller that does not have an open channel.
     */
    error ChannelClosed(address channel);

    /**
     * @dev Revert with an error when attempting to update a channel to the
     *      current status of that channel.
     */
    error ChannelStatusAlreadySet(address channel, bool isOpen);

    /**
     * @dev Revert with an error when attempting to execute a transfer for an
     *      item that does not have an ERC20/721/1155 item type.
     */
    error InvalidItemType();

    /**
     * @dev Revert with an error when attempting to update the status of a
     *      channel from a caller that is not the conduit controller.
     */
    error InvalidController();

    /**
     * @dev Emit an event whenever a channel is opened or closed.
     *
     * @param channel The channel that has been updated.
     * @param open    A boolean indicating whether the conduit is open or not.
     */
    event ChannelUpdated(address indexed channel, bool open);

    /**
     * @notice Execute a sequence of ERC20/721/1155 transfers. Only a caller
     *         with an open channel can call this function.
     *
     * @param transfers The ERC20/721/1155 transfers to perform.
     *
     * @return magicValue A magic value indicating that the transfers were
     *                    performed successfully.
     */
    function execute(ConduitTransfer[] calldata transfers)
        external
        returns (bytes4 magicValue);

    /**
     * @notice Execute a sequence of batch 1155 transfers. Only a caller with an
     *         open channel can call this function.
     *
     * @param batch1155Transfers The 1155 batch transfers to perform.
     *
     * @return magicValue A magic value indicating that the transfers were
     *                    performed successfully.
     */
    function executeBatch1155(
        ConduitBatch1155Transfer[] calldata batch1155Transfers
    ) external returns (bytes4 magicValue);

    /**
     * @notice Execute a sequence of transfers, both single and batch 1155. Only
     *         a caller with an open channel can call this function.
     *
     * @param standardTransfers  The ERC20/721/1155 transfers to perform.
     * @param batch1155Transfers The 1155 batch transfers to perform.
     *
     * @return magicValue A magic value indicating that the transfers were
     *                    performed successfully.
     */
    function executeWithBatch1155(
        ConduitTransfer[] calldata standardTransfers,
        ConduitBatch1155Transfer[] calldata batch1155Transfers
    ) external returns (bytes4 magicValue);

    /**
     * @notice Open or close a given channel. Only callable by the controller.
     *
     * @param channel The channel to open or close.
     * @param isOpen  The status of the channel (either open or closed).
     */
    function updateChannel(address channel, bool isOpen) external;
}

ConduitInterface.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

import { ConduitItemType } from "ConduitEnums.sol";

struct ConduitTransfer {
    ConduitItemType itemType;
    address token;
    address from;
    address to;
    uint256 identifier;
    uint256 amount;
}

struct ConduitBatch1155Transfer {
    address token;
    address from;
    address to;
    uint256[] ids;
    uint256[] amounts;
}

ConduitStructs.sol

Consideration.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.13;

// prettier-ignore
import {
    ConduitControllerInterface
} from "ConduitControllerInterface.sol";

// prettier-ignore
import {
    ConsiderationEventsAndErrors
} from "ConsiderationEventsAndErrors.sol";

import "ConsiderationConstants.sol";

/**
 * @title ConsiderationBase
 * @author 0age
 * @notice ConsiderationBase contains immutable constants and constructor logic.
 */
contract ConsiderationBase is ConsiderationEventsAndErrors {
    // Precompute hashes, original chainId, and domain separator on deployment.
    bytes32 internal immutable _NAME_HASH;
    bytes32 internal immutable _VERSION_HASH;
    bytes32 internal immutable _EIP_712_DOMAIN_TYPEHASH;
    bytes32 internal immutable _OFFER_ITEM_TYPEHASH;
    bytes32 internal immutable _CONSIDERATION_ITEM_TYPEHASH;
    bytes32 internal immutable _ORDER_TYPEHASH;
    uint256 internal immutable _CHAIN_ID;
    bytes32 internal immutable _DOMAIN_SEPARATOR;

    // Allow for interaction with the conduit controller.
    ConduitControllerInterface internal immutable _CONDUIT_CONTROLLER;

    // Cache the conduit creation code hash used by the conduit controller.
    bytes32 internal immutable _CONDUIT_CREATION_CODE_HASH;

    /**
     * @dev Derive and set hashes, reference chainId, and associated domain
     *      separator during deployment.
     *
     * @param conduitController A contract that deploys conduits, or proxies
     *                          that may optionally be used to transfer approved
     *                          ERC20/721/1155 tokens.
     */
    constructor(address conduitController) {
        // Derive name and version hashes alongside required EIP-712 typehashes.
        (
            _NAME_HASH,
            _VERSION_HASH,
            _EIP_712_DOMAIN_TYPEHASH,
            _OFFER_ITEM_TYPEHASH,
            _CONSIDERATION_ITEM_TYPEHASH,
            _ORDER_TYPEHASH
        ) = _deriveTypehashes();

        // Store the current chainId and derive the current domain separator.
        _CHAIN_ID = block.chainid;
        _DOMAIN_SEPARATOR = _deriveDomainSeparator();

        // Set the supplied conduit controller.
        _CONDUIT_CONTROLLER = ConduitControllerInterface(conduitController);

        // Retrieve the conduit creation code hash from the supplied controller.
        (_CONDUIT_CREATION_CODE_HASH, ) = (
            _CONDUIT_CONTROLLER.getConduitCodeHashes()
        );
    }

    /**
     * @dev Internal view function to derive the EIP-712 domain separator.
     *
     * @return The derived domain separator.
     */
    function _deriveDomainSeparator() internal view returns (bytes32) {
        // prettier-ignore
        return keccak256(
            abi.encode(
                _EIP_712_DOMAIN_TYPEHASH,
                _NAME_HASH,
                _VERSION_HASH,
                block.chainid,
                address(this)
            )
        );
    }

    /**
     * @dev Internal pure function to retrieve the default name of this
     *      contract and return.
     *
     * @return The name of this contract.
     */
    function _name() internal pure virtual returns (string memory) {
        // Return the name of the contract.
        assembly {
            // First element is the offset for the returned string. Offset the
            // value in memory by one word so that the free memory pointer will
            // be overwritten by the next write.
            mstore(OneWord, OneWord)

            // Name is right padded, so it touches the length which is left
            // padded. This enables writing both values at once. The free memory
            // pointer will be overwritten in the process.
            mstore(NameLengthPtr, NameWithLength)

            // Standard ABI encoding pads returned data to the nearest word. Use
            // the already empty zero slot memory region for this purpose and
            // return the final name string, offset by the original single word.
            return(OneWord, ThreeWords)
        }
    }

    /**
     * @dev Internal pure function to retrieve the default name of this contract
     *      as a string that can be used internally.
     *
     * @return The name of this contract.
     */
    function _nameString() internal pure virtual returns (string memory) {
        // Return the name of the contract.
        return "Consideration";
    }

    /**
     * @dev Internal pure function to derive required EIP-712 typehashes and
     *      other hashes during contract creation.
     *
     * @return nameHash                  The hash of the name of the contract.
     * @return versionHash               The hash of the version string of the
     *                                   contract.
     * @return eip712DomainTypehash      The primary EIP-712 domain typehash.
     * @return offerItemTypehash         The EIP-712 typehash for OfferItem
     *                                   types.
     * @return considerationItemTypehash The EIP-712 typehash for
     *                                   ConsiderationItem types.
     * @return orderTypehash             The EIP-712 typehash for Order types.
     */
    function _deriveTypehashes()
        internal
        pure
        returns (
            bytes32 nameHash,
            bytes32 versionHash,
            bytes32 eip712DomainTypehash,
            bytes32 offerItemTypehash,
            bytes32 considerationItemTypehash,
            bytes32 orderTypehash
        )
    {
        // Derive hash of the name of the contract.
        nameHash = keccak256(bytes(_nameString()));

        // Derive hash of the version string of the contract.
        versionHash = keccak256(bytes("1.1"));

        // Construct the OfferItem type string.
        // prettier-ignore
        bytes memory offerItemTypeString = abi.encodePacked(
            "OfferItem(",
                "uint8 itemType,",
                "address token,",
                "uint256 identifierOrCriteria,",
                "uint256 startAmount,",
                "uint256 endAmount",
            ")"
        );

        // Construct the ConsiderationItem type string.
        // prettier-ignore
        bytes memory considerationItemTypeString = abi.encodePacked(
            "ConsiderationItem(",
                "uint8 itemType,",
                "address token,",
                "uint256 identifierOrCriteria,",
                "uint256 startAmount,",
                "uint256 endAmount,",
                "address recipient",
            ")"
        );

        // Construct the OrderComponents type string, not including the above.
        // prettier-ignore
        bytes memory orderComponentsPartialTypeString = abi.encodePacked(
            "OrderComponents(",
                "address offerer,",
                "address zone,",
                "OfferItem[] offer,",
                "ConsiderationItem[] consideration,",
                "uint8 orderType,",
                "uint256 startTime,",
                "uint256 endTime,",
                "bytes32 zoneHash,",
                "uint256 salt,",
                "bytes32 conduitKey,",
                "uint256 counter",
            ")"
        );

        // Construct the primary EIP-712 domain type string.
        // prettier-ignore
        eip712DomainTypehash = keccak256(
            abi.encodePacked(
                "EIP712Domain(",
                    "string name,",
                    "string version,",
                    "uint256 chainId,",
                    "address verifyingContract",
                ")"
            )
        );

        // Derive the OfferItem type hash using the corresponding type string.
        offerItemTypehash = keccak256(offerItemTypeString);

        // Derive ConsiderationItem type hash using corresponding type string.
        considerationItemTypehash = keccak256(considerationItemTypeString);

        // Derive OrderItem type hash via combination of relevant type strings.
        orderTypehash = keccak256(
            abi.encodePacked(
                orderComponentsPartialTypeString,
                considerationItemTypeString,
                offerItemTypeString
            )
        );
    }
}

ConsiderationBase.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

/*
 * -------------------------- Disambiguation & Other Notes ---------------------
 *    - The term "head" is used as it is in the documentation for ABI encoding,
 *      but only in reference to dynamic types, i.e. it always refers to the
 *      offset or pointer to the body of a dynamic type. In calldata, the head
 *      is always an offset (relative to the parent object), while in memory,
 *      the head is always the pointer to the body. More information found here:
 *      https://docs.soliditylang.org/en/v0.8.14/abi-spec.html#argument-encoding
 *        - Note that the length of an array is separate from and precedes the
 *          head of the array.
 *
 *    - The term "body" is used in place of the term "head" used in the ABI
 *      documentation. It refers to the start of the data for a dynamic type,
 *      e.g. the first word of a struct or the first word of the first element
 *      in an array.
 *
 *    - The term "pointer" is used to describe the absolute position of a value
 *      and never an offset relative to another value.
 *        - The suffix "_ptr" refers to a memory pointer.
 *        - The suffix "_cdPtr" refers to a calldata pointer.
 *
 *    - The term "offset" is used to describe the position of a value relative
 *      to some parent value. For example, OrderParameters_conduit_offset is the
 *      offset to the "conduit" value in the OrderParameters struct relative to
 *      the start of the body.
 *        - Note: Offsets are used to derive pointers.
 *
 *    - Some structs have pointers defined for all of their fields in this file.
 *      Lines which are commented out are fields that are not used in the
 *      codebase but have been left in for readability.
 */

// Declare constants for name, version, and reentrancy sentinel values.

// Name is right padded, so it touches the length which is left padded. This
// enables writing both values at once. Length goes at byte 95 in memory, and
// name fills bytes 96-109, so both values can be written left-padded to 77.
uint256 constant NameLengthPtr = 77;
uint256 constant NameWithLength = 0x0d436F6E73696465726174696F6E;

uint256 constant Version = 0x312e31;
uint256 constant Version_length = 3;
uint256 constant Version_shift = 0xe8;

uint256 constant _NOT_ENTERED = 1;
uint256 constant _ENTERED = 2;

// Common Offsets
// Offsets for identically positioned fields shared by:
// OfferItem, ConsiderationItem, SpentItem, ReceivedItem

uint256 constant Common_token_offset = 0x20;
uint256 constant Common_identifier_offset = 0x40;
uint256 constant Common_amount_offset = 0x60;

uint256 constant ReceivedItem_size = 0xa0;
uint256 constant ReceivedItem_amount_offset = 0x60;
uint256 constant ReceivedItem_recipient_offset = 0x80;

uint256 constant ReceivedItem_CommonParams_size = 0x60;

uint256 constant ConsiderationItem_recipient_offset = 0xa0;
// Store the same constant in an abbreviated format for a line length fix.
uint256 constant ConsiderItem_recipient_offset = 0xa0;

uint256 constant Execution_offerer_offset = 0x20;
uint256 constant Execution_conduit_offset = 0x40;

uint256 constant InvalidFulfillmentComponentData_error_signature = (
    0x7fda727900000000000000000000000000000000000000000000000000000000
);
uint256 constant InvalidFulfillmentComponentData_error_len = 0x04;

uint256 constant Panic_error_signature = (
    0x4e487b7100000000000000000000000000000000000000000000000000000000
);
uint256 constant Panic_error_offset = 0x04;
uint256 constant Panic_error_length = 0x24;
uint256 constant Panic_arithmetic = 0x11;

uint256 constant MissingItemAmount_error_signature = (
    0x91b3e51400000000000000000000000000000000000000000000000000000000
);
uint256 constant MissingItemAmount_error_len = 0x04;

uint256 constant OrderParameters_offer_head_offset = 0x40;
uint256 constant OrderParameters_consideration_head_offset = 0x60;
uint256 constant OrderParameters_conduit_offset = 0x120;
uint256 constant OrderParameters_counter_offset = 0x140;

uint256 constant Fulfillment_itemIndex_offset = 0x20;

uint256 constant AdvancedOrder_numerator_offset = 0x20;

uint256 constant AlmostOneWord = 0x1f;
uint256 constant OneWord = 0x20;
uint256 constant TwoWords = 0x40;
uint256 constant ThreeWords = 0x60;
uint256 constant FourWords = 0x80;
uint256 constant FiveWords = 0xa0;

uint256 constant FreeMemoryPointerSlot = 0x40;
uint256 constant ZeroSlot = 0x60;
uint256 constant DefaultFreeMemoryPointer = 0x80;

uint256 constant Slot0x80 = 0x80;
uint256 constant Slot0xA0 = 0xa0;

uint256 constant BasicOrder_endAmount_cdPtr = 0x104;
uint256 constant BasicOrder_common_params_size = 0xa0;
uint256 constant BasicOrder_considerationHashesArray_ptr = 0x160;

uint256 constant EIP712_Order_size = 0x180;
uint256 constant EIP712_OfferItem_size = 0xc0;
uint256 constant EIP712_ConsiderationItem_size = 0xe0;
uint256 constant AdditionalRecipients_size = 0x40;

uint256 constant EIP712_DomainSeparator_offset = 0x02;
uint256 constant EIP712_OrderHash_offset = 0x22;
uint256 constant EIP712_DigestPayload_size = 0x42;

uint256 constant receivedItemsHash_ptr = 0x60;

/*
 *  Memory layout in _prepareBasicFulfillmentFromCalldata of
 *  data for OrderFulfilled
 *
 *   event OrderFulfilled(
 *     bytes32 orderHash,
 *     address indexed offerer,
 *     address indexed zone,
 *     address fulfiller,
 *     SpentItem[] offer,
 *       > (itemType, token, id, amount)
 *     ReceivedItem[] consideration
 *       > (itemType, token, id, amount, recipient)
 *   )
 *
 *  - 0x00: orderHash
 *  - 0x20: fulfiller
 *  - 0x40: offer offset (0x80)
 *  - 0x60: consideration offset (0x120)
 *  - 0x80: offer.length (1)
 *  - 0xa0: offerItemType
 *  - 0xc0: offerToken
 *  - 0xe0: offerIdentifier
 *  - 0x100: offerAmount
 *  - 0x120: consideration.length (1 + additionalRecipients.length)
 *  - 0x140: considerationItemType
 *  - 0x160: considerationToken
 *  - 0x180: considerationIdentifier
 *  - 0x1a0: considerationAmount
 *  - 0x1c0: considerationRecipient
 *  - ...
 */

// Minimum length of the OrderFulfilled event data.
// Must be added to the size of the ReceivedItem array for additionalRecipients
// (0xa0 * additionalRecipients.length) to calculate full size of the buffer.
uint256 constant OrderFulfilled_baseSize = 0x1e0;
uint256 constant OrderFulfilled_selector = (
    0x9d9af8e38d66c62e2c12f0225249fd9d721c54b83f48d9352c97c6cacdcb6f31
);

// Minimum offset in memory to OrderFulfilled event data.
// Must be added to the size of the EIP712 hash array for additionalRecipients
// (32 * additionalRecipients.length) to calculate the pointer to event data.
uint256 constant OrderFulfilled_baseOffset = 0x180;
uint256 constant OrderFulfilled_consideration_length_baseOffset = 0x2a0;
uint256 constant OrderFulfilled_offer_length_baseOffset = 0x200;

// uint256 constant OrderFulfilled_orderHash_offset = 0x00;
uint256 constant OrderFulfilled_fulfiller_offset = 0x20;
uint256 constant OrderFulfilled_offer_head_offset = 0x40;
uint256 constant OrderFulfilled_offer_body_offset = 0x80;
uint256 constant OrderFulfilled_consideration_head_offset = 0x60;
uint256 constant OrderFulfilled_consideration_body_offset = 0x120;

// BasicOrderParameters
uint256 constant BasicOrder_parameters_cdPtr = 0x04;
uint256 constant BasicOrder_considerationToken_cdPtr = 0x24;
// uint256 constant BasicOrder_considerationIdentifier_cdPtr = 0x44;
uint256 constant BasicOrder_considerationAmount_cdPtr = 0x64;
uint256 constant BasicOrder_offerer_cdPtr = 0x84;
uint256 constant BasicOrder_zone_cdPtr = 0xa4;
uint256 constant BasicOrder_offerToken_cdPtr = 0xc4;
// uint256 constant BasicOrder_offerIdentifier_cdPtr = 0xe4;
uint256 constant BasicOrder_offerAmount_cdPtr = 0x104;
uint256 constant BasicOrder_basicOrderType_cdPtr = 0x124;
uint256 constant BasicOrder_startTime_cdPtr = 0x144;
// uint256 constant BasicOrder_endTime_cdPtr = 0x164;
// uint256 constant BasicOrder_zoneHash_cdPtr = 0x184;
// uint256 constant BasicOrder_salt_cdPtr = 0x1a4;
uint256 constant BasicOrder_offererConduit_cdPtr = 0x1c4;
uint256 constant BasicOrder_fulfillerConduit_cdPtr = 0x1e4;
uint256 constant BasicOrder_totalOriginalAdditionalRecipients_cdPtr = 0x204;
uint256 constant BasicOrder_additionalRecipients_head_cdPtr = 0x224;
uint256 constant BasicOrder_signature_cdPtr = 0x244;
uint256 constant BasicOrder_additionalRecipients_length_cdPtr = 0x264;
uint256 constant BasicOrder_additionalRecipients_data_cdPtr = 0x284;

uint256 constant BasicOrder_parameters_ptr = 0x20;

uint256 constant BasicOrder_basicOrderType_range = 0x18; // 24 values

/*
 *  Memory layout in _prepareBasicFulfillmentFromCalldata of
 *  EIP712 data for ConsiderationItem
 *   - 0x80: ConsiderationItem EIP-712 typehash (constant)
 *   - 0xa0: itemType
 *   - 0xc0: token
 *   - 0xe0: identifier
 *   - 0x100: startAmount
 *   - 0x120: endAmount
 *   - 0x140: recipient
 */
uint256 constant BasicOrder_considerationItem_typeHash_ptr = 0x80; // memoryPtr
uint256 constant BasicOrder_considerationItem_itemType_ptr = 0xa0;
uint256 constant BasicOrder_considerationItem_token_ptr = 0xc0;
uint256 constant BasicOrder_considerationItem_identifier_ptr = 0xe0;
uint256 constant BasicOrder_considerationItem_startAmount_ptr = 0x100;
uint256 constant BasicOrder_considerationItem_endAmount_ptr = 0x120;
// uint256 constant BasicOrder_considerationItem_recipient_ptr = 0x140;

/*
 *  Memory layout in _prepareBasicFulfillmentFromCalldata of
 *  EIP712 data for OfferItem
 *   - 0x80:  OfferItem EIP-712 typehash (constant)
 *   - 0xa0:  itemType
 *   - 0xc0:  token
 *   - 0xe0:  identifier (reused for offeredItemsHash)
 *   - 0x100: startAmount
 *   - 0x120: endAmount
 */
uint256 constant BasicOrder_offerItem_typeHash_ptr = DefaultFreeMemoryPointer;
uint256 constant BasicOrder_offerItem_itemType_ptr = 0xa0;
uint256 constant BasicOrder_offerItem_token_ptr = 0xc0;
// uint256 constant BasicOrder_offerItem_identifier_ptr = 0xe0;
// uint256 constant BasicOrder_offerItem_startAmount_ptr = 0x100;
uint256 constant BasicOrder_offerItem_endAmount_ptr = 0x120;

/*
 *  Memory layout in _prepareBasicFulfillmentFromCalldata of
 *  EIP712 data for Order
 *   - 0x80:   Order EIP-712 typehash (constant)
 *   - 0xa0:   orderParameters.offerer
 *   - 0xc0:   orderParameters.zone
 *   - 0xe0:   keccak256(abi.encodePacked(offerHashes))
 *   - 0x100:  keccak256(abi.encodePacked(considerationHashes))
 *   - 0x120:  orderType
 *   - 0x140:  startTime
 *   - 0x160:  endTime
 *   - 0x180:  zoneHash
 *   - 0x1a0:  salt
 *   - 0x1c0:  conduit
 *   - 0x1e0:  _counters[orderParameters.offerer] (from storage)
 */
uint256 constant BasicOrder_order_typeHash_ptr = 0x80;
uint256 constant BasicOrder_order_offerer_ptr = 0xa0;
// uint256 constant BasicOrder_order_zone_ptr = 0xc0;
uint256 constant BasicOrder_order_offerHashes_ptr = 0xe0;
uint256 constant BasicOrder_order_considerationHashes_ptr = 0x100;
uint256 constant BasicOrder_order_orderType_ptr = 0x120;
uint256 constant BasicOrder_order_startTime_ptr = 0x140;
// uint256 constant BasicOrder_order_endTime_ptr = 0x160;
// uint256 constant BasicOrder_order_zoneHash_ptr = 0x180;
// uint256 constant BasicOrder_order_salt_ptr = 0x1a0;
// uint256 constant BasicOrder_order_conduitKey_ptr = 0x1c0;
uint256 constant BasicOrder_order_counter_ptr = 0x1e0;
uint256 constant BasicOrder_additionalRecipients_head_ptr = 0x240;
uint256 constant BasicOrder_signature_ptr = 0x260;

// Signature-related
bytes32 constant EIP2098_allButHighestBitMask = (
    0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
);
bytes32 constant ECDSA_twentySeventhAndTwentyEighthBytesSet = (
    0x0000000000000000000000000000000000000000000000000000000101000000
);
uint256 constant ECDSA_MaxLength = 65;
uint256 constant ECDSA_signature_s_offset = 0x40;
uint256 constant ECDSA_signature_v_offset = 0x60;

bytes32 constant EIP1271_isValidSignature_selector = (
    0x1626ba7e00000000000000000000000000000000000000000000000000000000
);
uint256 constant EIP1271_isValidSignature_signatureHead_negativeOffset = 0x20;
uint256 constant EIP1271_isValidSignature_digest_negativeOffset = 0x40;
uint256 constant EIP1271_isValidSignature_selector_negativeOffset = 0x44;
uint256 constant EIP1271_isValidSignature_calldata_baseLength = 0x64;

uint256 constant EIP1271_isValidSignature_signature_head_offset = 0x40;

// abi.encodeWithSignature("NoContract(address)")
uint256 constant NoContract_error_signature = (
    0x5f15d67200000000000000000000000000000000000000000000000000000000
);
uint256 constant NoContract_error_sig_ptr = 0x0;
uint256 constant NoContract_error_token_ptr = 0x4;
uint256 constant NoContract_error_length = 0x24; // 4 + 32 == 36

uint256 constant EIP_712_PREFIX = (
    0x1901000000000000000000000000000000000000000000000000000000000000
);

uint256 constant ExtraGasBuffer = 0x20;
uint256 constant CostPerWord = 3;
uint256 constant MemoryExpansionCoefficient = 0x200; // 512

uint256 constant Create2AddressDerivation_ptr = 0x0b;
uint256 constant Create2AddressDerivation_length = 0x55;

uint256 constant MaskOverByteTwelve = (
    0x0000000000000000000000ff0000000000000000000000000000000000000000
);

uint256 constant MaskOverLastTwentyBytes = (
    0x000000000000000000000000ffffffffffffffffffffffffffffffffffffffff
);

uint256 constant MaskOverFirstFourBytes = (
    0xffffffff00000000000000000000000000000000000000000000000000000000
);

uint256 constant Conduit_execute_signature = (
    0x4ce34aa200000000000000000000000000000000000000000000000000000000
);

uint256 constant MaxUint8 = 0xff;
uint256 constant MaxUint120 = 0xffffffffffffffffffffffffffffff;

uint256 constant Conduit_execute_ConduitTransfer_ptr = 0x20;
uint256 constant Conduit_execute_ConduitTransfer_length = 0x01;

uint256 constant Conduit_execute_ConduitTransfer_offset_ptr = 0x04;
uint256 constant Conduit_execute_ConduitTransfer_length_ptr = 0x24;
uint256 constant Conduit_execute_transferItemType_ptr = 0x44;
uint256 constant Conduit_execute_transferToken_ptr = 0x64;
uint256 constant Conduit_execute_transferFrom_ptr = 0x84;
uint256 constant Conduit_execute_transferTo_ptr = 0xa4;
uint256 constant Conduit_execute_transferIdentifier_ptr = 0xc4;
uint256 constant Conduit_execute_transferAmount_ptr = 0xe4;

uint256 constant OneConduitExecute_size = 0x104;

// Sentinel value to indicate that the conduit accumulator is not armed.
uint256 constant AccumulatorDisarmed = 0x20;
uint256 constant AccumulatorArmed = 0x40;
uint256 constant Accumulator_conduitKey_ptr = 0x20;
uint256 constant Accumulator_selector_ptr = 0x40;
uint256 constant Accumulator_array_offset_ptr = 0x44;
uint256 constant Accumulator_array_length_ptr = 0x64;

uint256 constant Accumulator_itemSizeOffsetDifference = 0x3c;

uint256 constant Accumulator_array_offset = 0x20;
uint256 constant Conduit_transferItem_size = 0xc0;
uint256 constant Conduit_transferItem_token_ptr = 0x20;
uint256 constant Conduit_transferItem_from_ptr = 0x40;
uint256 constant Conduit_transferItem_to_ptr = 0x60;
uint256 constant Conduit_transferItem_identifier_ptr = 0x80;
uint256 constant Conduit_transferItem_amount_ptr = 0xa0;

// Declare constant for errors related to amount derivation.
// error InexactFraction() @ AmountDerivationErrors.sol
uint256 constant InexactFraction_error_signature = (
    0xc63cf08900000000000000000000000000000000000000000000000000000000
);
uint256 constant InexactFraction_error_len = 0x04;

// Declare constant for errors related to signature verification.
uint256 constant Ecrecover_precompile = 1;
uint256 constant Ecrecover_args_size = 0x80;
uint256 constant Signature_lower_v = 27;

// error BadSignatureV(uint8) @ SignatureVerificationErrors.sol
uint256 constant BadSignatureV_error_signature = (
    0x1f003d0a00000000000000000000000000000000000000000000000000000000
);
uint256 constant BadSignatureV_error_offset = 0x04;
uint256 constant BadSignatureV_error_length = 0x24;

// error InvalidSigner() @ SignatureVerificationErrors.sol
uint256 constant InvalidSigner_error_signature = (
    0x815e1d6400000000000000000000000000000000000000000000000000000000
);
uint256 constant InvalidSigner_error_length = 0x04;

// error InvalidSignature() @ SignatureVerificationErrors.sol
uint256 constant InvalidSignature_error_signature = (
    0x8baa579f00000000000000000000000000000000000000000000000000000000
);
uint256 constant InvalidSignature_error_length = 0x04;

// error BadContractSignature() @ SignatureVerificationErrors.sol
uint256 constant BadContractSignature_error_signature = (
    0x4f7fb80d00000000000000000000000000000000000000000000000000000000
);
uint256 constant BadContractSignature_error_length = 0x04;

uint256 constant NumBitsAfterSelector = 0xe0;

// 69 is the lowest modulus for which the remainder
// of every selector other than the two match functions
// is greater than those of the match functions.
uint256 constant NonMatchSelector_MagicModulus = 69;
// Of the two match function selectors, the highest
// remainder modulo 69 is 29.
uint256 constant NonMatchSelector_MagicRemainder = 0x1d;

ConsiderationConstants.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

// prettier-ignore
enum OrderType {
    // 0: no partial fills, anyone can execute
    FULL_OPEN,

    // 1: partial fills supported, anyone can execute
    PARTIAL_OPEN,

    // 2: no partial fills, only offerer or zone can execute
    FULL_RESTRICTED,

    // 3: partial fills supported, only offerer or zone can execute
    PARTIAL_RESTRICTED
}

// prettier-ignore
enum BasicOrderType {
    // 0: no partial fills, anyone can execute
    ETH_TO_ERC721_FULL_OPEN,

    // 1: partial fills supported, anyone can execute
    ETH_TO_ERC721_PARTIAL_OPEN,

    // 2: no partial fills, only offerer or zone can execute
    ETH_TO_ERC721_FULL_RESTRICTED,

    // 3: partial fills supported, only offerer or zone can execute
    ETH_TO_ERC721_PARTIAL_RESTRICTED,

    // 4: no partial fills, anyone can execute
    ETH_TO_ERC1155_FULL_OPEN,

    // 5: partial fills supported, anyone can execute
    ETH_TO_ERC1155_PARTIAL_OPEN,

    // 6: no partial fills, only offerer or zone can execute
    ETH_TO_ERC1155_FULL_RESTRICTED,

    // 7: partial fills supported, only offerer or zone can execute
    ETH_TO_ERC1155_PARTIAL_RESTRICTED,

    // 8: no partial fills, anyone can execute
    ERC20_TO_ERC721_FULL_OPEN,

    // 9: partial fills supported, anyone can execute
    ERC20_TO_ERC721_PARTIAL_OPEN,

    // 10: no partial fills, only offerer or zone can execute
    ERC20_TO_ERC721_FULL_RESTRICTED,

    // 11: partial fills supported, only offerer or zone can execute
    ERC20_TO_ERC721_PARTIAL_RESTRICTED,

    // 12: no partial fills, anyone can execute
    ERC20_TO_ERC1155_FULL_OPEN,

    // 13: partial fills supported, anyone can execute
    ERC20_TO_ERC1155_PARTIAL_OPEN,

    // 14: no partial fills, only offerer or zone can execute
    ERC20_TO_ERC1155_FULL_RESTRICTED,

    // 15: partial fills supported, only offerer or zone can execute
    ERC20_TO_ERC1155_PARTIAL_RESTRICTED,

    // 16: no partial fills, anyone can execute
    ERC721_TO_ERC20_FULL_OPEN,

    // 17: partial fills supported, anyone can execute
    ERC721_TO_ERC20_PARTIAL_OPEN,

    // 18: no partial fills, only offerer or zone can execute
    ERC721_TO_ERC20_FULL_RESTRICTED,

    // 19: partial fills supported, only offerer or zone can execute
    ERC721_TO_ERC20_PARTIAL_RESTRICTED,

    // 20: no partial fills, anyone can execute
    ERC1155_TO_ERC20_FULL_OPEN,

    // 21: partial fills supported, anyone can execute
    ERC1155_TO_ERC20_PARTIAL_OPEN,

    // 22: no partial fills, only offerer or zone can execute
    ERC1155_TO_ERC20_FULL_RESTRICTED,

    // 23: partial fills supported, only offerer or zone can execute
    ERC1155_TO_ERC20_PARTIAL_RESTRICTED
}

// prettier-ignore
enum BasicOrderRouteType {
    // 0: provide Ether (or other native token) to receive offered ERC721 item.
    ETH_TO_ERC721,

    // 1: provide Ether (or other native token) to receive offered ERC1155 item.
    ETH_TO_ERC1155,

    // 2: provide ERC20 item to receive offered ERC721 item.
    ERC20_TO_ERC721,

    // 3: provide ERC20 item to receive offered ERC1155 item.
    ERC20_TO_ERC1155,

    // 4: provide ERC721 item to receive offered ERC20 item.
    ERC721_TO_ERC20,

    // 5: provide ERC1155 item to receive offered ERC20 item.
    ERC1155_TO_ERC20
}

// prettier-ignore
enum ItemType {
    // 0: ETH on mainnet, MATIC on polygon, etc.
    NATIVE,

    // 1: ERC20 items (ERC777 and ERC20 analogues could also technically work)
    ERC20,

    // 2: ERC721 items
    ERC721,

    // 3: ERC1155 items
    ERC1155,

    // 4: ERC721 items where a number of tokenIds are supported
    ERC721_WITH_CRITERIA,

    // 5: ERC1155 items where a number of ids are supported
    ERC1155_WITH_CRITERIA
}

// prettier-ignore
enum Side {
    // 0: Items that can be spent
    OFFER,

    // 1: Items that must be received
    CONSIDERATION
}

ConsiderationEnums.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

import { SpentItem, ReceivedItem } from "ConsiderationStructs.sol";

/**
 * @title ConsiderationEventsAndErrors
 * @author 0age
 * @notice ConsiderationEventsAndErrors contains all events and errors.
 */
interface ConsiderationEventsAndErrors {
    /**
     * @dev Emit an event whenever an order is successfully fulfilled.
     *
     * @param orderHash     The hash of the fulfilled order.
     * @param offerer       The offerer of the fulfilled order.
     * @param zone          The zone of the fulfilled order.
     * @param recipient     The recipient of each spent item on the fulfilled
     *                      order, or the null address if there is no specific
     *                      fulfiller (i.e. the order is part of a group of
     *                      orders). Defaults to the caller unless explicitly
     *                      specified otherwise by the fulfiller.
     * @param offer         The offer items spent as part of the order.
     * @param consideration The consideration items received as part of the
     *                      order along with the recipients of each item.
     */
    event OrderFulfilled(
        bytes32 orderHash,
        address indexed offerer,
        address indexed zone,
        address recipient,
        SpentItem[] offer,
        ReceivedItem[] consideration
    );

    /**
     * @dev Emit an event whenever an order is successfully cancelled.
     *
     * @param orderHash The hash of the cancelled order.
     * @param offerer   The offerer of the cancelled order.
     * @param zone      The zone of the cancelled order.
     */
    event OrderCancelled(
        bytes32 orderHash,
        address indexed offerer,
        address indexed zone
    );

    /**
     * @dev Emit an event whenever an order is explicitly validated. Note that
     *      this event will not be emitted on partial fills even though they do
     *      validate the order as part of partial fulfillment.
     *
     * @param orderHash The hash of the validated order.
     * @param offerer   The offerer of the validated order.
     * @param zone      The zone of the validated order.
     */
    event OrderValidated(
        bytes32 orderHash,
        address indexed offerer,
        address indexed zone
    );

    /**
     * @dev Emit an event whenever a counter for a given offerer is incremented.
     *
     * @param newCounter The new counter for the offerer.
     * @param offerer  The offerer in question.
     */
    event CounterIncremented(uint256 newCounter, address indexed offerer);

    /**
     * @dev Revert with an error when attempting to fill an order that has
     *      already been fully filled.
     *
     * @param orderHash The order hash on which a fill was attempted.
     */
    error OrderAlreadyFilled(bytes32 orderHash);

    /**
     * @dev Revert with an error when attempting to fill an order outside the
     *      specified start time and end time.
     */
    error InvalidTime();

    /**
     * @dev Revert with an error when attempting to fill an order referencing an
     *      invalid conduit (i.e. one that has not been deployed).
     */
    error InvalidConduit(bytes32 conduitKey, address conduit);

    /**
     * @dev Revert with an error when an order is supplied for fulfillment with
     *      a consideration array that is shorter than the original array.
     */
    error MissingOriginalConsiderationItems();

    /**
     * @dev Revert with an error when a call to a conduit fails with revert data
     *      that is too expensive to return.
     */
    error InvalidCallToConduit(address conduit);

    /**
     * @dev Revert with an error if a consideration amount has not been fully
     *      zeroed out after applying all fulfillments.
     *
     * @param orderIndex         The index of the order with the consideration
     *                           item with a shortfall.
     * @param considerationIndex The index of the consideration item on the
     *                           order.
     * @param shortfallAmount    The unfulfilled consideration amount.
     */
    error ConsiderationNotMet(
        uint256 orderIndex,
        uint256 considerationIndex,
        uint256 shortfallAmount
    );

    /**
     * @dev Revert with an error when insufficient ether is supplied as part of
     *      msg.value when fulfilling orders.
     */
    error InsufficientEtherSupplied();

    /**
     * @dev Revert with an error when an ether transfer reverts.
     */
    error EtherTransferGenericFailure(address account, uint256 amount);

    /**
     * @dev Revert with an error when a partial fill is attempted on an order
     *      that does not specify partial fill support in its order type.
     */
    error PartialFillsNotEnabledForOrder();

    /**
     * @dev Revert with an error when attempting to fill an order that has been
     *      cancelled.
     *
     * @param orderHash The hash of the cancelled order.
     */
    error OrderIsCancelled(bytes32 orderHash);

    /**
     * @dev Revert with an error when attempting to fill a basic order that has
     *      been partially filled.
     *
     * @param orderHash The hash of the partially used order.
     */
    error OrderPartiallyFilled(bytes32 orderHash);

    /**
     * @dev Revert with an error when attempting to cancel an order as a caller
     *      other than the indicated offerer or zone.
     */
    error InvalidCanceller();

    /**
     * @dev Revert with an error when supplying a fraction with a value of zero
     *      for the numerator or denominator, or one where the numerator exceeds
     *      the denominator.
     */
    error BadFraction();

    /**
     * @dev Revert with an error when a caller attempts to supply callvalue to a
     *      non-payable basic order route or does not supply any callvalue to a
     *      payable basic order route.
     */
    error InvalidMsgValue(uint256 value);

    /**
     * @dev Revert with an error when attempting to fill a basic order using
     *      calldata not produced by default ABI encoding.
     */
    error InvalidBasicOrderParameterEncoding();

    /**
     * @dev Revert with an error when attempting to fulfill any number of
     *      available orders when none are fulfillable.
     */
    error NoSpecifiedOrdersAvailable();

    /**
     * @dev Revert with an error when attempting to fulfill an order with an
     *      offer for ETH outside of matching orders.
     */
    error InvalidNativeOfferItem();
}

ConsiderationEventsAndErrors.sol

ConsiderationInterface.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

// prettier-ignore
import {
    OrderType,
    BasicOrderType,
    ItemType,
    Side
} from "ConsiderationEnums.sol";

/**
 * @dev An order contains eleven components: an offerer, a zone (or account that
 *      can cancel the order or restrict who can fulfill the order depending on
 *      the type), the order type (specifying partial fill support as well as
 *      restricted order status), the start and end time, a hash that will be
 *      provided to the zone when validating restricted orders, a salt, a key
 *      corresponding to a given conduit, a counter, and an arbitrary number of
 *      offer items that can be spent along with consideration items that must
 *      be received by their respective recipient.
 */
struct OrderComponents {
    address offerer;
    address zone;
    OfferItem[] offer;
    ConsiderationItem[] consideration;
    OrderType orderType;
    uint256 startTime;
    uint256 endTime;
    bytes32 zoneHash;
    uint256 salt;
    bytes32 conduitKey;
    uint256 counter;
}

/**
 * @dev An offer item has five components: an item type (ETH or other native
 *      tokens, ERC20, ERC721, and ERC1155, as well as criteria-based ERC721 and
 *      ERC1155), a token address, a dual-purpose "identifierOrCriteria"
 *      component that will either represent a tokenId or a merkle root
 *      depending on the item type, and a start and end amount that support
 *      increasing or decreasing amounts over the duration of the respective
 *      order.
 */
struct OfferItem {
    ItemType itemType;
    address token;
    uint256 identifierOrCriteria;
    uint256 startAmount;
    uint256 endAmount;
}

/**
 * @dev A consideration item has the same five components as an offer item and
 *      an additional sixth component designating the required recipient of the
 *      item.
 */
struct ConsiderationItem {
    ItemType itemType;
    address token;
    uint256 identifierOrCriteria;
    uint256 startAmount;
    uint256 endAmount;
    address payable recipient;
}

/**
 * @dev A spent item is translated from a utilized offer item and has four
 *      components: an item type (ETH or other native tokens, ERC20, ERC721, and
 *      ERC1155), a token address, a tokenId, and an amount.
 */
struct SpentItem {
    ItemType itemType;
    address token;
    uint256 identifier;
    uint256 amount;
}

/**
 * @dev A received item is translated from a utilized consideration item and has
 *      the same four components as a spent item, as well as an additional fifth
 *      component designating the required recipient of the item.
 */
struct ReceivedItem {
    ItemType itemType;
    address token;
    uint256 identifier;
    uint256 amount;
    address payable recipient;
}

/**
 * @dev For basic orders involving ETH / native / ERC20 <=> ERC721 / ERC1155
 *      matching, a group of six functions may be called that only requires a
 *      subset of the usual order arguments. Note the use of a "basicOrderType"
 *      enum; this represents both the usual order type as well as the "route"
 *      of the basic order (a simple derivation function for the basic order
 *      type is `basicOrderType = orderType + (4 * basicOrderRoute)`.)
 */
struct BasicOrderParameters {
    // calldata offset
    address considerationToken; // 0x24
    uint256 considerationIdentifier; // 0x44
    uint256 considerationAmount; // 0x64
    address payable offerer; // 0x84
    address zone; // 0xa4
    address offerToken; // 0xc4
    uint256 offerIdentifier; // 0xe4
    uint256 offerAmount; // 0x104
    BasicOrderType basicOrderType; // 0x124
    uint256 startTime; // 0x144
    uint256 endTime; // 0x164
    bytes32 zoneHash; // 0x184
    uint256 salt; // 0x1a4
    bytes32 offererConduitKey; // 0x1c4
    bytes32 fulfillerConduitKey; // 0x1e4
    uint256 totalOriginalAdditionalRecipients; // 0x204
    AdditionalRecipient[] additionalRecipients; // 0x224
    bytes signature; // 0x244
    // Total length, excluding dynamic array data: 0x264 (580)
}

/**
 * @dev Basic orders can supply any number of additional recipients, with the
 *      implied assumption that they are supplied from the offered ETH (or other
 *      native token) or ERC20 token for the order.
 */
struct AdditionalRecipient {
    uint256 amount;
    address payable recipient;
}

/**
 * @dev The full set of order components, with the exception of the counter,
 *      must be supplied when fulfilling more sophisticated orders or groups of
 *      orders. The total number of original consideration items must also be
 *      supplied, as the caller may specify additional consideration items.
 */
struct OrderParameters {
    address offerer; // 0x00
    address zone; // 0x20
    OfferItem[] offer; // 0x40
    ConsiderationItem[] consideration; // 0x60
    OrderType orderType; // 0x80
    uint256 startTime; // 0xa0
    uint256 endTime; // 0xc0
    bytes32 zoneHash; // 0xe0
    uint256 salt; // 0x100
    bytes32 conduitKey; // 0x120
    uint256 totalOriginalConsiderationItems; // 0x140
    // offer.length                          // 0x160
}

/**
 * @dev Orders require a signature in addition to the other order parameters.
 */
struct Order {
    OrderParameters parameters;
    bytes signature;
}

/**
 * @dev Advanced orders include a numerator (i.e. a fraction to attempt to fill)
 *      and a denominator (the total size of the order) in addition to the
 *      signature and other order parameters. It also supports an optional field
 *      for supplying extra data; this data will be included in a staticcall to
 *      `isValidOrderIncludingExtraData` on the zone for the order if the order
 *      type is restricted and the offerer or zone are not the caller.
 */
struct AdvancedOrder {
    OrderParameters parameters;
    uint120 numerator;
    uint120 denominator;
    bytes signature;
    bytes extraData;
}

/**
 * @dev Orders can be validated (either explicitly via `validate`, or as a
 *      consequence of a full or partial fill), specifically cancelled (they can
 *      also be cancelled in bulk via incrementing a per-zone counter), and
 *      partially or fully filled (with the fraction filled represented by a
 *      numerator and denominator).
 */
struct OrderStatus {
    bool isValidated;
    bool isCancelled;
    uint120 numerator;
    uint120 denominator;
}

/**
 * @dev A criteria resolver specifies an order, side (offer vs. consideration),
 *      and item index. It then provides a chosen identifier (i.e. tokenId)
 *      alongside a merkle proof demonstrating the identifier meets the required
 *      criteria.
 */
struct CriteriaResolver {
    uint256 orderIndex;
    Side side;
    uint256 index;
    uint256 identifier;
    bytes32[] criteriaProof;
}

/**
 * @dev A fulfillment is applied to a group of orders. It decrements a series of
 *      offer and consideration items, then generates a single execution
 *      element. A given fulfillment can be applied to as many offer and
 *      consideration items as desired, but must contain at least one offer and
 *      at least one consideration that match. The fulfillment must also remain
 *      consistent on all key parameters across all offer items (same offerer,
 *      token, type, tokenId, and conduit preference) as well as across all
 *      consideration items (token, type, tokenId, and recipient).
 */
struct Fulfillment {
    FulfillmentComponent[] offerComponents;
    FulfillmentComponent[] considerationComponents;
}

/**
 * @dev Each fulfillment component contains one index referencing a specific
 *      order and another referencing a specific offer or consideration item.
 */
struct FulfillmentComponent {
    uint256 orderIndex;
    uint256 itemIndex;
}

/**
 * @dev An execution is triggered once all consideration items have been zeroed
 *      out. It sends the item in question from the offerer to the item's
 *      recipient, optionally sourcing approvals from either this contract
 *      directly or from the offerer's chosen conduit if one is specified. An
 *      execution is not provided as an argument, but rather is derived via
 *      orders, criteria resolvers, and fulfillments (where the total number of
 *      executions will be less than or equal to the total number of indicated
 *      fulfillments) and returned as part of `matchOrders`.
 */
struct Execution {
    ReceivedItem item;
    address offerer;
    bytes32 conduitKey;
}

ConsiderationStructs.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.13;

// prettier-ignore
import {
    ConsiderationEventsAndErrors
} from "ConsiderationEventsAndErrors.sol";

import { ReentrancyGuard } from "ReentrancyGuard.sol";

/**
 * @title CounterManager
 * @author 0age
 * @notice CounterManager contains a storage mapping and related functionality
 *         for retrieving and incrementing a per-offerer counter.
 */
contract CounterManager is ConsiderationEventsAndErrors, ReentrancyGuard {
    // Only orders signed using an offerer's current counter are fulfillable.
    mapping(address => uint256) private _counters;

    /**
     * @dev Internal function to cancel all orders from a given offerer with a
     *      given zone in bulk by incrementing a counter. Note that only the
     *      offerer may increment the counter.
     *
     * @return newCounter The new counter.
     */
    function _incrementCounter() internal returns (uint256 newCounter) {
        // Ensure that the reentrancy guard is not currently set.
        _assertNonReentrant();

        // Skip overflow check as counter cannot be incremented that far.
        unchecked {
            // Increment current counter for the supplied offerer.
            newCounter = ++_counters[msg.sender];
        }

        // Emit an event containing the new counter.
        emit CounterIncremented(newCounter, msg.sender);
    }

    /**
     * @dev Internal view function to retrieve the current counter for a given
     *      offerer.
     *
     * @param offerer The offerer in question.
     *
     * @return currentCounter The current counter.
     */
    function _getCounter(address offerer)
        internal
        view
        returns (uint256 currentCounter)
    {
        // Return the counter for the supplied offerer.
        currentCounter = _counters[offerer];
    }
}

CounterManager.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.13;

import { ItemType, Side } from "ConsiderationEnums.sol";

// prettier-ignore
import {
    OfferItem,
    ConsiderationItem,
    OrderParameters,
    AdvancedOrder,
    CriteriaResolver
} from "ConsiderationStructs.sol";

import "ConsiderationConstants.sol";

// prettier-ignore
import {
    CriteriaResolutionErrors
} from "CriteriaResolutionErrors.sol";

/**
 * @title CriteriaResolution
 * @author 0age
 * @notice CriteriaResolution contains a collection of pure functions related to
 *         resolving criteria-based items.
 */
contract CriteriaResolution is CriteriaResolutionErrors {
    /**
     * @dev Internal pure function to apply criteria resolvers containing
     *      specific token identifiers and associated proofs to order items.
     *
     * @param advancedOrders     The orders to apply criteria resolvers to.
     * @param criteriaResolvers  An array where each element contains a
     *                           reference to a specific order as well as that
     *                           order's offer or consideration, a token
     *                           identifier, and a proof that the supplied token
     *                           identifier is contained in the order's merkle
     *                           root. Note that a root of zero indicates that
     *                           any transferable token identifier is valid and
     *                           that no proof needs to be supplied.
     */
    function _applyCriteriaResolvers(
        AdvancedOrder[] memory advancedOrders,
        CriteriaResolver[] memory criteriaResolvers
    ) internal pure {
        // Skip overflow checks as all for loops are indexed starting at zero.
        unchecked {
            // Retrieve length of criteria resolvers array and place on stack.
            uint256 totalCriteriaResolvers = criteriaResolvers.length;

            // Retrieve length of orders array and place on stack.
            uint256 totalAdvancedOrders = advancedOrders.length;

            // Iterate over each criteria resolver.
            for (uint256 i = 0; i < totalCriteriaResolvers; ++i) {
                // Retrieve the criteria resolver.
                CriteriaResolver memory criteriaResolver = (
                    criteriaResolvers[i]
                );

                // Read the order index from memory and place it on the stack.
                uint256 orderIndex = criteriaResolver.orderIndex;

                // Ensure that the order index is in range.
                if (orderIndex >= totalAdvancedOrders) {
                    revert OrderCriteriaResolverOutOfRange();
                }

                // Skip criteria resolution for order if not fulfilled.
                if (advancedOrders[orderIndex].numerator == 0) {
                    continue;
                }

                // Retrieve the parameters for the order.
                OrderParameters memory orderParameters = (
                    advancedOrders[orderIndex].parameters
                );

                // Read component index from memory and place it on the stack.
                uint256 componentIndex = criteriaResolver.index;

                // Declare values for item's type and criteria.
                ItemType itemType;
                uint256 identifierOrCriteria;

                // If the criteria resolver refers to an offer item...
                if (criteriaResolver.side == Side.OFFER) {
                    // Retrieve the offer.
                    OfferItem[] memory offer = orderParameters.offer;

                    // Ensure that the component index is in range.
                    if (componentIndex >= offer.length) {
                        revert OfferCriteriaResolverOutOfRange();
                    }

                    // Retrieve relevant item using the component index.
                    OfferItem memory offerItem = offer[componentIndex];

                    // Read item type and criteria from memory & place on stack.
                    itemType = offerItem.itemType;
                    identifierOrCriteria = offerItem.identifierOrCriteria;

                    // Optimistically update item type to remove criteria usage.
                    // Use assembly to operate on ItemType enum as a number.
                    ItemType newItemType;
                    assembly {
                        // Item type 4 becomes 2 and item type 5 becomes 3.
                        newItemType := sub(3, eq(itemType, 4))
                    }
                    offerItem.itemType = newItemType;

                    // Optimistically update identifier w/ supplied identifier.
                    offerItem.identifierOrCriteria = criteriaResolver
                        .identifier;
                } else {
                    // Otherwise, the resolver refers to a consideration item.
                    ConsiderationItem[] memory consideration = (
                        orderParameters.consideration
                    );

                    // Ensure that the component index is in range.
                    if (componentIndex >= consideration.length) {
                        revert ConsiderationCriteriaResolverOutOfRange();
                    }

                    // Retrieve relevant item using order and component index.
                    ConsiderationItem memory considerationItem = (
                        consideration[componentIndex]
                    );

                    // Read item type and criteria from memory & place on stack.
                    itemType = considerationItem.itemType;
                    identifierOrCriteria = (
                        considerationItem.identifierOrCriteria
                    );

                    // Optimistically update item type to remove criteria usage.
                    // Use assembly to operate on ItemType enum as a number.
                    ItemType newItemType;
                    assembly {
                        // Item type 4 becomes 2 and item type 5 becomes 3.
                        newItemType := sub(3, eq(itemType, 4))
                    }
                    considerationItem.itemType = newItemType;

                    // Optimistically update identifier w/ supplied identifier.
                    considerationItem.identifierOrCriteria = (
                        criteriaResolver.identifier
                    );
                }

                // Ensure the specified item type indicates criteria usage.
                if (!_isItemWithCriteria(itemType)) {
                    revert CriteriaNotEnabledForItem();
                }

                // If criteria is not 0 (i.e. a collection-wide offer)...
                if (identifierOrCriteria != uint256(0)) {
                    // Verify identifier inclusion in criteria root using proof.
                    _verifyProof(
                        criteriaResolver.identifier,
                        identifierOrCriteria,
                        criteriaResolver.criteriaProof
                    );
                }
            }

            // Iterate over each advanced order.
            for (uint256 i = 0; i < totalAdvancedOrders; ++i) {
                // Retrieve the advanced order.
                AdvancedOrder memory advancedOrder = advancedOrders[i];

                // Skip criteria resolution for order if not fulfilled.
                if (advancedOrder.numerator == 0) {
                    continue;
                }

                // Retrieve the parameters for the order.
                OrderParameters memory orderParameters = (
                    advancedOrder.parameters
                );

                // Read consideration length from memory and place on stack.
                uint256 totalItems = orderParameters.consideration.length;

                // Iterate over each consideration item on the order.
                for (uint256 j = 0; j < totalItems; ++j) {
                    // Ensure item type no longer indicates criteria usage.
                    if (
                        _isItemWithCriteria(
                            orderParameters.consideration[j].itemType
                        )
                    ) {
                        revert UnresolvedConsiderationCriteria();
                    }
                }

                // Read offer length from memory and place on stack.
                totalItems = orderParameters.offer.length;

                // Iterate over each offer item on the order.
                for (uint256 j = 0; j < totalItems; ++j) {
                    // Ensure item type no longer indicates criteria usage.
                    if (
                        _isItemWithCriteria(orderParameters.offer[j].itemType)
                    ) {
                        revert UnresolvedOfferCriteria();
                    }
                }
            }
        }
    }

    /**
     * @dev Internal pure function to check whether a given item type represents
     *      a criteria-based ERC721 or ERC1155 item (e.g. an item that can be
     *      resolved to one of a number of different identifiers at the time of
     *      order fulfillment).
     *
     * @param itemType The item type in question.
     *
     * @return withCriteria A boolean indicating that the item type in question
     *                      represents a criteria-based item.
     */
    function _isItemWithCriteria(ItemType itemType)
        internal
        pure
        returns (bool withCriteria)
    {
        // ERC721WithCriteria is ItemType 4. ERC1155WithCriteria is ItemType 5.
        assembly {
            withCriteria := gt(itemType, 3)
        }
    }

    /**
     * @dev Internal pure function to ensure that a given element is contained
     *      in a merkle root via a supplied proof.
     *
     * @param leaf  The element for which to prove inclusion.
     * @param root  The merkle root that inclusion will be proved against.
     * @param proof The merkle proof.
     */
    function _verifyProof(
        uint256 leaf,
        uint256 root,
        bytes32[] memory proof
    ) internal pure {
        // Declare a variable that will be used to determine proof validity.
        bool isValid;

        // Utilize assembly to efficiently verify the proof against the root.
        assembly {
            // Store the leaf at the beginning of scratch space.
            mstore(0, leaf)

            // Derive the hash of the leaf to use as the initial proof element.
            let computedHash := keccak256(0, OneWord)

            // Based on: https://github.com/Rari-Capital/solmate/blob/v7/src/utils/MerkleProof.sol
            // Get memory start location of the first element in proof array.
            let data := add(proof, OneWord)

            // Iterate over each proof element to compute the root hash.
            for {
                // Left shift by 5 is equivalent to multiplying by 0x20.
                let end := add(data, shl(5, mload(proof)))
            } lt(data, end) {
                // Increment by one word at a time.
                data := add(data, OneWord)
            } {
                // Get the proof element.
                let loadedData := mload(data)

                // Sort proof elements and place them in scratch space.
                // Slot of `computedHash` in scratch space.
                // If the condition is true: 0x20, otherwise: 0x00.
                let scratch := shl(5, gt(computedHash, loadedData))

                // Store elements to hash contiguously in scratch space. Scratch
                // space is 64 bytes (0x00 - 0x3f) & both elements are 32 bytes.
                mstore(scratch, computedHash)
                mstore(xor(scratch, OneWord), loadedData)

                // Derive the updated hash.
                computedHash := keccak256(0, TwoWords)
            }

            // Compare the final hash to the supplied root.
            isValid := eq(computedHash, root)
        }

        // Revert if computed hash does not equal supplied root.
        if (!isValid) {
            revert InvalidProof();
        }
    }
}

CriteriaResolution.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

/**
 * @title CriteriaResolutionErrors
 * @author 0age
 * @notice CriteriaResolutionErrors contains all errors related to criteria
 *         resolution.
 */
interface CriteriaResolutionErrors {
    /**
     * @dev Revert with an error when providing a criteria resolver that refers
     *      to an order that has not been supplied.
     */
    error OrderCriteriaResolverOutOfRange();

    /**
     * @dev Revert with an error if an offer item still has unresolved criteria
     *      after applying all criteria resolvers.
     */
    error UnresolvedOfferCriteria();

    /**
     * @dev Revert with an error if a consideration item still has unresolved
     *      criteria after applying all criteria resolvers.
     */
    error UnresolvedConsiderationCriteria();

    /**
     * @dev Revert with an error when providing a criteria resolver that refers
     *      to an order with an offer item that has not been supplied.
     */
    error OfferCriteriaResolverOutOfRange();

    /**
     * @dev Revert with an error when providing a criteria resolver that refers
     *      to an order with a consideration item that has not been supplied.
     */
    error ConsiderationCriteriaResolverOutOfRange();

    /**
     * @dev Revert with an error when providing a criteria resolver that refers
     *      to an order with an item that does not expect a criteria to be
     *      resolved.
     */
    error CriteriaNotEnabledForItem();

    /**
     * @dev Revert with an error when providing a criteria resolver that
     *      contains an invalid proof with respect to the given item and
     *      chosen identifier.
     */
    error InvalidProof();
}

CriteriaResolutionErrors.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

interface EIP1271Interface {
    function isValidSignature(bytes32 digest, bytes calldata signature)
        external
        view
        returns (bytes4);
}

EIP1271Interface.sol

Executor.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

import { Side } from "ConsiderationEnums.sol";

/**
 * @title FulfillmentApplicationErrors
 * @author 0age
 * @notice FulfillmentApplicationErrors contains errors related to fulfillment
 *         application and aggregation.
 */
interface FulfillmentApplicationErrors {
    /**
     * @dev Revert with an error when a fulfillment is provided that does not
     *      declare at least one component as part of a call to fulfill
     *      available orders.
     */
    error MissingFulfillmentComponentOnAggregation(Side side);

    /**
     * @dev Revert with an error when a fulfillment is provided that does not
     *      declare at least one offer component and at least one consideration
     *      component.
     */
    error OfferAndConsiderationRequiredOnFulfillment();

    /**
     * @dev Revert with an error when the initial offer item named by a
     *      fulfillment component does not match the type, token, identifier,
     *      or conduit preference of the initial consideration item.
     */
    error MismatchedFulfillmentOfferAndConsiderationComponents();

    /**
     * @dev Revert with an error when an order or item index are out of range
     *      or a fulfillment component does not match the type, token,
     *      identifier, or conduit preference of the initial consideration item.
     */
    error InvalidFulfillmentComponentData();
}

FulfillmentApplicationErrors.sol

FulfillmentApplier.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.13;

import { OrderParameters } from "ConsiderationStructs.sol";

import { ConsiderationBase } from "ConsiderationBase.sol";

import "ConsiderationConstants.sol";

/**
 * @title GettersAndDerivers
 * @author 0age
 * @notice ConsiderationInternal contains pure and internal view functions
 *         related to getting or deriving various values.
 */
contract GettersAndDerivers is ConsiderationBase {
    /**
     * @dev Derive and set hashes, reference chainId, and associated domain
     *      separator during deployment.
     *
     * @param conduitController A contract that deploys conduits, or proxies
     *                          that may optionally be used to transfer approved
     *                          ERC20/721/1155 tokens.
     */
    constructor(address conduitController)
        ConsiderationBase(conduitController)
    {}

    /**
     * @dev Internal view function to derive the order hash for a given order.
     *      Note that only the original consideration items are included in the
     *      order hash, as additional consideration items may be supplied by the
     *      caller.
     *
     * @param orderParameters The parameters of the order to hash.
     * @param counter           The counter of the order to hash.
     *
     * @return orderHash The hash.
     */
    function _deriveOrderHash(
        OrderParameters memory orderParameters,
        uint256 counter
    ) internal view returns (bytes32 orderHash) {
        // Get length of original consideration array and place it on the stack.
        uint256 originalConsiderationLength = (
            orderParameters.totalOriginalConsiderationItems
        );

        /*
         * Memory layout for an array of structs (dynamic or not) is similar
         * to ABI encoding of dynamic types, with a head segment followed by
         * a data segment. The main difference is that the head of an element
         * is a memory pointer rather than an offset.
         */

        // Declare a variable for the derived hash of the offer array.
        bytes32 offerHash;

        // Read offer item EIP-712 typehash from runtime code & place on stack.
        bytes32 typeHash = _OFFER_ITEM_TYPEHASH;

        // Utilize assembly so that memory regions can be reused across hashes.
        assembly {
            // Retrieve the free memory pointer and place on the stack.
            let hashArrPtr := mload(FreeMemoryPointerSlot)

            // Get the pointer to the offers array.
            let offerArrPtr := mload(
                add(orderParameters, OrderParameters_offer_head_offset)
            )

            // Load the length.
            let offerLength := mload(offerArrPtr)

            // Set the pointer to the first offer's head.
            offerArrPtr := add(offerArrPtr, OneWord)

            // Iterate over the offer items.
            // prettier-ignore
            for { let i := 0 } lt(i, offerLength) {
                i := add(i, 1)
            } {
                // Read the pointer to the offer data and subtract one word
                // to get typeHash pointer.
                let ptr := sub(mload(offerArrPtr), OneWord)

                // Read the current value before the offer data.
                let value := mload(ptr)

                // Write the type hash to the previous word.
                mstore(ptr, typeHash)

                // Take the EIP712 hash and store it in the hash array.
                mstore(hashArrPtr, keccak256(ptr, EIP712_OfferItem_size))

                // Restore the previous word.
                mstore(ptr, value)

                // Increment the array pointers by one word.
                offerArrPtr := add(offerArrPtr, OneWord)
                hashArrPtr := add(hashArrPtr, OneWord)
            }

            // Derive the offer hash using the hashes of each item.
            offerHash := keccak256(
                mload(FreeMemoryPointerSlot),
                mul(offerLength, OneWord)
            )
        }

        // Declare a variable for the derived hash of the consideration array.
        bytes32 considerationHash;

        // Read consideration item typehash from runtime code & place on stack.
        typeHash = _CONSIDERATION_ITEM_TYPEHASH;

        // Utilize assembly so that memory regions can be reused across hashes.
        assembly {
            // Retrieve the free memory pointer and place on the stack.
            let hashArrPtr := mload(FreeMemoryPointerSlot)

            // Get the pointer to the consideration array.
            let considerationArrPtr := add(
                mload(
                    add(
                        orderParameters,
                        OrderParameters_consideration_head_offset
                    )
                ),
                OneWord
            )

            // Iterate over the consideration items (not including tips).
            // prettier-ignore
            for { let i := 0 } lt(i, originalConsiderationLength) {
                i := add(i, 1)
            } {
                // Read the pointer to the consideration data and subtract one
                // word to get typeHash pointer.
                let ptr := sub(mload(considerationArrPtr), OneWord)

                // Read the current value before the consideration data.
                let value := mload(ptr)

                // Write the type hash to the previous word.
                mstore(ptr, typeHash)

                // Take the EIP712 hash and store it in the hash array.
                mstore(
                    hashArrPtr,
                    keccak256(ptr, EIP712_ConsiderationItem_size)
                )

                // Restore the previous word.
                mstore(ptr, value)

                // Increment the array pointers by one word.
                considerationArrPtr := add(considerationArrPtr, OneWord)
                hashArrPtr := add(hashArrPtr, OneWord)
            }

            // Derive the consideration hash using the hashes of each item.
            considerationHash := keccak256(
                mload(FreeMemoryPointerSlot),
                mul(originalConsiderationLength, OneWord)
            )
        }

        // Read order item EIP-712 typehash from runtime code & place on stack.
        typeHash = _ORDER_TYPEHASH;

        // Utilize assembly to access derived hashes & other arguments directly.
        assembly {
            // Retrieve pointer to the region located just behind parameters.
            let typeHashPtr := sub(orderParameters, OneWord)

            // Store the value at that pointer location to restore later.
            let previousValue := mload(typeHashPtr)

            // Store the order item EIP-712 typehash at the typehash location.
            mstore(typeHashPtr, typeHash)

            // Retrieve the pointer for the offer array head.
            let offerHeadPtr := add(
                orderParameters,
                OrderParameters_offer_head_offset
            )

            // Retrieve the data pointer referenced by the offer head.
            let offerDataPtr := mload(offerHeadPtr)

            // Store the offer hash at the retrieved memory location.
            mstore(offerHeadPtr, offerHash)

            // Retrieve the pointer for the consideration array head.
            let considerationHeadPtr := add(
                orderParameters,
                OrderParameters_consideration_head_offset
            )

            // Retrieve the data pointer referenced by the consideration head.
            let considerationDataPtr := mload(considerationHeadPtr)

            // Store the consideration hash at the retrieved memory location.
            mstore(considerationHeadPtr, considerationHash)

            // Retrieve the pointer for the counter.
            let counterPtr := add(
                orderParameters,
                OrderParameters_counter_offset
            )

            // Store the counter at the retrieved memory location.
            mstore(counterPtr, counter)

            // Derive the order hash using the full range of order parameters.
            orderHash := keccak256(typeHashPtr, EIP712_Order_size)

            // Restore the value previously held at typehash pointer location.
            mstore(typeHashPtr, previousValue)

            // Restore offer data pointer at the offer head pointer location.
            mstore(offerHeadPtr, offerDataPtr)

            // Restore consideration data pointer at the consideration head ptr.
            mstore(considerationHeadPtr, considerationDataPtr)

            // Restore consideration item length at the counter pointer.
            mstore(counterPtr, originalConsiderationLength)
        }
    }

    /**
     * @dev Internal view function to derive the address of a given conduit
     *      using a corresponding conduit key.
     *
     * @param conduitKey A bytes32 value indicating what corresponding conduit,
     *                   if any, to source token approvals from. This value is
     *                   the "salt" parameter supplied by the deployer (i.e. the
     *                   conduit controller) when deploying the given conduit.
     *
     * @return conduit The address of the conduit associated with the given
     *                 conduit key.
     */
    function _deriveConduit(bytes32 conduitKey)
        internal
        view
        returns (address conduit)
    {
        // Read conduit controller address from runtime and place on the stack.
        address conduitController = address(_CONDUIT_CONTROLLER);

        // Read conduit creation code hash from runtime and place on the stack.
        bytes32 conduitCreationCodeHash = _CONDUIT_CREATION_CODE_HASH;

        // Leverage scratch space to perform an efficient hash.
        assembly {
            // Retrieve the free memory pointer; it will be replaced afterwards.
            let freeMemoryPointer := mload(FreeMemoryPointerSlot)

            // Place the control character and the conduit controller in scratch
            // space; note that eleven bytes at the beginning are left unused.
            mstore(0, or(MaskOverByteTwelve, conduitController))

            // Place the conduit key in the next region of scratch space.
            mstore(OneWord, conduitKey)

            // Place conduit creation code hash in free memory pointer location.
            mstore(TwoWords, conduitCreationCodeHash)

            // Derive conduit by hashing and applying a mask over last 20 bytes.
            conduit := and(
                // Hash the relevant region.
                keccak256(
                    // The region starts at memory pointer 11.
                    Create2AddressDerivation_ptr,
                    // The region is 85 bytes long (1 + 20 + 32 + 32).
                    Create2AddressDerivation_length
                ),
                // The address equals the last twenty bytes of the hash.
                MaskOverLastTwentyBytes
            )

            // Restore the free memory pointer.
            mstore(FreeMemoryPointerSlot, freeMemoryPointer)
        }
    }

    /**
     * @dev Internal view function to get the EIP-712 domain separator. If the
     *      chainId matches the chainId set on deployment, the cached domain
     *      separator will be returned; otherwise, it will be derived from
     *      scratch.
     *
     * @return The domain separator.
     */
    function _domainSeparator() internal view returns (bytes32) {
        // prettier-ignore
        return block.chainid == _CHAIN_ID
            ? _DOMAIN_SEPARATOR
            : _deriveDomainSeparator();
    }

    /**
     * @dev Internal view function to retrieve configuration information for
     *      this contract.
     *
     * @return version           The contract version.
     * @return domainSeparator   The domain separator for this contract.
     * @return conduitController The conduit Controller set for this contract.
     */
    function _information()
        internal
        view
        returns (
            string memory version,
            bytes32 domainSeparator,
            address conduitController
        )
    {
        // Derive the domain separator.
        domainSeparator = _domainSeparator();

        // Declare variable as immutables cannot be accessed within assembly.
        conduitController = address(_CONDUIT_CONTROLLER);

        // Allocate a string with the intended length.
        version = new string(Version_length);

        // Set the version as data on the newly allocated string.
        assembly {
            mstore(add(version, OneWord), shl(Version_shift, Version))
        }
    }

    /**
     * @dev Internal pure function to efficiently derive an digest to sign for
     *      an order in accordance with EIP-712.
     *
     * @param domainSeparator The domain separator.
     * @param orderHash       The order hash.
     *
     * @return value The hash.
     */
    function _deriveEIP712Digest(bytes32 domainSeparator, bytes32 orderHash)
        internal
        pure
        returns (bytes32 value)
    {
        // Leverage scratch space to perform an efficient hash.
        assembly {
            // Place the EIP-712 prefix at the start of scratch space.
            mstore(0, EIP_712_PREFIX)

            // Place the domain separator in the next region of scratch space.
            mstore(EIP712_DomainSeparator_offset, domainSeparator)

            // Place the order hash in scratch space, spilling into the first
            // two bytes of the free memory pointer — this should never be set
            // as memory cannot be expanded to that size, and will be zeroed out
            // after the hash is performed.
            mstore(EIP712_OrderHash_offset, orderHash)

            // Hash the relevant region (65 bytes).
            value := keccak256(0, EIP712_DigestPayload_size)

            // Clear out the dirtied bits in the memory pointer.
            mstore(EIP712_OrderHash_offset, 0)
        }
    }
}

GettersAndDerivers.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.13;

import "ConsiderationConstants.sol";

/**
 * @title LowLevelHelpers
 * @author 0age
 * @notice LowLevelHelpers contains logic for performing various low-level
 *         operations.
 */
contract LowLevelHelpers {
    /**
     * @dev Internal view function to staticcall an arbitrary target with given
     *      calldata. Note that no data is written to memory and no contract
     *      size check is performed.
     *
     * @param target   The account to staticcall.
     * @param callData The calldata to supply when staticcalling the target.
     *
     * @return success The status of the staticcall to the target.
     */
    function _staticcall(address target, bytes memory callData)
        internal
        view
        returns (bool success)
    {
        assembly {
            // Perform the staticcall.
            success := staticcall(
                gas(),
                target,
                add(callData, OneWord),
                mload(callData),
                0,
                0
            )
        }
    }

    /**
     * @dev Internal view function to revert and pass along the revert reason if
     *      data was returned by the last call and that the size of that data
     *      does not exceed the currently allocated memory size.
     */
    function _revertWithReasonIfOneIsReturned() internal view {
        assembly {
            // If it returned a message, bubble it up as long as sufficient gas
            // remains to do so:
            if returndatasize() {
                // Ensure that sufficient gas is available to copy returndata
                // while expanding memory where necessary. Start by computing
                // the word size of returndata and allocated memory.
                let returnDataWords := div(
                    add(returndatasize(), AlmostOneWord),
                    OneWord
                )

                // Note: use the free memory pointer in place of msize() to work
                // around a Yul warning that prevents accessing msize directly
                // when the IR pipeline is activated.
                let msizeWords := div(mload(FreeMemoryPointerSlot), OneWord)

                // Next, compute the cost of the returndatacopy.
                let cost := mul(CostPerWord, returnDataWords)

                // Then, compute cost of new memory allocation.
                if gt(returnDataWords, msizeWords) {
                    cost := add(
                        cost,
                        add(
                            mul(sub(returnDataWords, msizeWords), CostPerWord),
                            div(
                                sub(
                                    mul(returnDataWords, returnDataWords),
                                    mul(msizeWords, msizeWords)
                                ),
                                MemoryExpansionCoefficient
                            )
                        )
                    )
                }

                // Finally, add a small constant and compare to gas remaining;
                // bubble up the revert data if enough gas is still available.
                if lt(add(cost, ExtraGasBuffer), gas()) {
                    // Copy returndata to memory; overwrite existing memory.
                    returndatacopy(0, 0, returndatasize())

                    // Revert, specifying memory region with copied returndata.
                    revert(0, returndatasize())
                }
            }
        }
    }

    /**
     * @dev Internal pure function to determine if the first word of returndata
     *      matches an expected magic value.
     *
     * @param expected The expected magic value.
     *
     * @return A boolean indicating whether the expected value matches the one
     *         located in the first word of returndata.
     */
    function _doesNotMatchMagic(bytes4 expected) internal pure returns (bool) {
        // Declare a variable for the value held by the return data buffer.
        bytes4 result;

        // Utilize assembly in order to read directly from returndata buffer.
        assembly {
            // Only put result on stack if return data is exactly one word.
            if eq(returndatasize(), OneWord) {
                // Copy the word directly from return data into scratch space.
                returndatacopy(0, 0, OneWord)

                // Take value from scratch space and place it on the stack.
                result := mload(0)
            }
        }

        // Return a boolean indicating whether expected and located value match.
        return result != expected;
    }
}

LowLevelHelpers.sol

OrderCombiner.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.13;

import { ItemType } from "ConsiderationEnums.sol";

// prettier-ignore
import {
    OfferItem,
    ConsiderationItem,
    SpentItem,
    ReceivedItem,
    OrderParameters,
    Order,
    AdvancedOrder,
    CriteriaResolver
} from "ConsiderationStructs.sol";

import { BasicOrderFulfiller } from "BasicOrderFulfiller.sol";

import { CriteriaResolution } from "CriteriaResolution.sol";

import { AmountDeriver } from "AmountDeriver.sol";

import "ConsiderationConstants.sol";

/**
 * @title OrderFulfiller
 * @author 0age
 * @notice OrderFulfiller contains logic related to order fulfillment where a
 *         single order is being fulfilled and where basic order fulfillment is
 *         not available as an option.
 */
contract OrderFulfiller is
    BasicOrderFulfiller,
    CriteriaResolution,
    AmountDeriver
{
    /**
     * @dev Derive and set hashes, reference chainId, and associated domain
     *      separator during deployment.
     *
     * @param conduitController A contract that deploys conduits, or proxies
     *                          that may optionally be used to transfer approved
     *                          ERC20/721/1155 tokens.
     */
    constructor(address conduitController)
        BasicOrderFulfiller(conduitController)
    {}

    /**
     * @dev Internal function to validate an order and update its status, adjust
     *      prices based on current time, apply criteria resolvers, determine
     *      what portion to fill, and transfer relevant tokens.
     *
     * @param advancedOrder       The order to fulfill as well as the fraction
     *                            to fill. Note that all offer and consideration
     *                            components must divide with no remainder for
     *                            the partial fill to be valid.
     * @param criteriaResolvers   An array where each element contains a
     *                            reference to a specific offer or
     *                            consideration, a token identifier, and a proof
     *                            that the supplied token identifier is
     *                            contained in the order's merkle root. Note
     *                            that a criteria of zero indicates that any
     *                            (transferable) token identifier is valid and
     *                            that no proof needs to be supplied.
     * @param fulfillerConduitKey A bytes32 value indicating what conduit, if
     *                            any, to source the fulfiller's token approvals
     *                            from. The zero hash signifies that no conduit
     *                            should be used, with direct approvals set on
     *                            Consideration.
     * @param recipient           The intended recipient for all received items.
     *
     * @return A boolean indicating whether the order has been fulfilled.
     */
    function _validateAndFulfillAdvancedOrder(
        AdvancedOrder memory advancedOrder,
        CriteriaResolver[] memory criteriaResolvers,
        bytes32 fulfillerConduitKey,
        address recipient
    ) internal returns (bool) {
        // Ensure this function cannot be triggered during a reentrant call.
        _setReentrancyGuard();

        // Declare empty bytes32 array (unused, will remain empty).
        bytes32[] memory priorOrderHashes;

        // Validate order, update status, and determine fraction to fill.
        (
            bytes32 orderHash,
            uint256 fillNumerator,
            uint256 fillDenominator
        ) = _validateOrderAndUpdateStatus(
                advancedOrder,
                criteriaResolvers,
                true,
                priorOrderHashes
            );

        // Create an array with length 1 containing the order.
        AdvancedOrder[] memory advancedOrders = new AdvancedOrder[](1);

        // Populate the order as the first and only element of the new array.
        advancedOrders[0] = advancedOrder;

        // Apply criteria resolvers using generated orders and details arrays.
        _applyCriteriaResolvers(advancedOrders, criteriaResolvers);

        // Retrieve the order parameters after applying criteria resolvers.
        OrderParameters memory orderParameters = advancedOrders[0].parameters;

        // Perform each item transfer with the appropriate fractional amount.
        _applyFractionsAndTransferEach(
            orderParameters,
            fillNumerator,
            fillDenominator,
            fulfillerConduitKey,
            recipient
        );

        // Emit an event signifying that the order has been fulfilled.
        _emitOrderFulfilledEvent(
            orderHash,
            orderParameters.offerer,
            orderParameters.zone,
            recipient,
            orderParameters.offer,
            orderParameters.consideration
        );

        // Clear the reentrancy guard.
        _clearReentrancyGuard();

        return true;
    }

    /**
     * @dev Internal function to transfer each item contained in a given single
     *      order fulfillment after applying a respective fraction to the amount
     *      being transferred.
     *
     * @param orderParameters     The parameters for the fulfilled order.
     * @param numerator           A value indicating the portion of the order
     *                            that should be filled.
     * @param denominator         A value indicating the total order size.
     * @param fulfillerConduitKey A bytes32 value indicating what conduit, if
     *                            any, to source the fulfiller's token approvals
     *                            from. The zero hash signifies that no conduit
     *                            should be used, with direct approvals set on
     *                            Consideration.
     * @param recipient           The intended recipient for all received items.
     */
    function _applyFractionsAndTransferEach(
        OrderParameters memory orderParameters,
        uint256 numerator,
        uint256 denominator,
        bytes32 fulfillerConduitKey,
        address recipient
    ) internal {
        // Read start time & end time from order parameters and place on stack.
        uint256 startTime = orderParameters.startTime;
        uint256 endTime = orderParameters.endTime;

        // Initialize an accumulator array. From this point forward, no new
        // memory regions can be safely allocated until the accumulator is no
        // longer being utilized, as the accumulator operates in an open-ended
        // fashion from this memory pointer; existing memory may still be
        // accessed and modified, however.
        bytes memory accumulator = new bytes(AccumulatorDisarmed);

        // As of solidity 0.6.0, inline assembly cannot directly access function
        // definitions, but can still access locally scoped function variables.
        // This means that in order to recast the type of a function, we need to
        // create a local variable to reference the internal function definition
        // (using the same type) and a local variable with the desired type,
        // and then cast the original function pointer to the desired type.

        /**
         * Repurpose existing OfferItem memory regions on the offer array for
         * the order by overriding the _transfer function pointer to accept a
         * modified OfferItem argument in place of the usual ReceivedItem:
         *
         *   ========= OfferItem ==========   ====== ReceivedItem ======
         *   ItemType itemType; ------------> ItemType itemType;
         *   address token; ----------------> address token;
         *   uint256 identifierOrCriteria; -> uint256 identifier;
         *   uint256 startAmount; ----------> uint256 amount;
         *   uint256 endAmount; ------------> address recipient;
         */

        // Declare a nested scope to minimize stack depth.
        unchecked {
            // Declare a virtual function pointer taking an OfferItem argument.
            function(OfferItem memory, address, bytes32, bytes memory)
                internal _transferOfferItem;

            {
                // Assign _transfer function to a new function pointer (it takes
                // a ReceivedItem as its initial argument)
                function(ReceivedItem memory, address, bytes32, bytes memory)
                    internal _transferReceivedItem = _transfer;

                // Utilize assembly to override the virtual function pointer.
                assembly {
                    // Cast initial ReceivedItem type to an OfferItem type.
                    _transferOfferItem := _transferReceivedItem
                }
            }

            // Read offer array length from memory and place on stack.
            uint256 totalOfferItems = orderParameters.offer.length;

            // Iterate over each offer on the order.
            // Skip overflow check as for loop is indexed starting at zero.
            for (uint256 i = 0; i < totalOfferItems; ++i) {
                // Retrieve the offer item.
                OfferItem memory offerItem = orderParameters.offer[i];

                // Offer items for the native token can not be received
                // outside of a match order function.
                if (offerItem.itemType == ItemType.NATIVE) {
                    revert InvalidNativeOfferItem();
                }

                // Declare an additional nested scope to minimize stack depth.
                {
                    // Apply fill fraction to get offer item amount to transfer.
                    uint256 amount = _applyFraction(
                        offerItem.startAmount,
                        offerItem.endAmount,
                        numerator,
                        denominator,
                        startTime,
                        endTime,
                        false
                    );

                    // Utilize assembly to set overloaded offerItem arguments.
                    assembly {
                        // Write new fractional amount to startAmount as amount.
                        mstore(
                            add(offerItem, ReceivedItem_amount_offset),
                            amount
                        )

                        // Write recipient to endAmount.
                        mstore(
                            add(offerItem, ReceivedItem_recipient_offset),
                            recipient
                        )
                    }
                }

                // Transfer the item from the offerer to the recipient.
                _transferOfferItem(
                    offerItem,
                    orderParameters.offerer,
                    orderParameters.conduitKey,
                    accumulator
                );
            }
        }

        // Put ether value supplied by the caller on the stack.
        uint256 etherRemaining = msg.value;

        /**
         * Repurpose existing ConsiderationItem memory regions on the
         * consideration array for the order by overriding the _transfer
         * function pointer to accept a modified ConsiderationItem argument in
         * place of the usual ReceivedItem:
         *
         *   ====== ConsiderationItem =====   ====== ReceivedItem ======
         *   ItemType itemType; ------------> ItemType itemType;
         *   address token; ----------------> address token;
         *   uint256 identifierOrCriteria;--> uint256 identifier;
         *   uint256 startAmount; ----------> uint256 amount;
         *   uint256 endAmount;        /----> address recipient;
         *   address recipient; ------/
         */

        // Declare a nested scope to minimize stack depth.
        unchecked {
            // Declare virtual function pointer with ConsiderationItem argument.
            function(ConsiderationItem memory, address, bytes32, bytes memory)
                internal _transferConsiderationItem;
            {
                // Reassign _transfer function to a new function pointer (it
                // takes a ReceivedItem as its initial argument).
                function(ReceivedItem memory, address, bytes32, bytes memory)
                    internal _transferReceivedItem = _transfer;

                // Utilize assembly to override the virtual function pointer.
                assembly {
                    // Cast ReceivedItem type to ConsiderationItem type.
                    _transferConsiderationItem := _transferReceivedItem
                }
            }

            // Read consideration array length from memory and place on stack.
            uint256 totalConsiderationItems = orderParameters
                .consideration
                .length;

            // Iterate over each consideration item on the order.
            // Skip overflow check as for loop is indexed starting at zero.
            for (uint256 i = 0; i < totalConsiderationItems; ++i) {
                // Retrieve the consideration item.
                ConsiderationItem memory considerationItem = (
                    orderParameters.consideration[i]
                );

                // Apply fraction & derive considerationItem amount to transfer.
                uint256 amount = _applyFraction(
                    considerationItem.startAmount,
                    considerationItem.endAmount,
                    numerator,
                    denominator,
                    startTime,
                    endTime,
                    true
                );

                // Use assembly to set overloaded considerationItem arguments.
                assembly {
                    // Write derived fractional amount to startAmount as amount.
                    mstore(
                        add(considerationItem, ReceivedItem_amount_offset),
                        amount
                    )

                    // Write original recipient to endAmount as recipient.
                    mstore(
                        add(considerationItem, ReceivedItem_recipient_offset),
                        mload(
                            add(
                                considerationItem,
                                ConsiderationItem_recipient_offset
                            )
                        )
                    )
                }

                // Reduce available value if offer spent ETH or a native token.
                if (considerationItem.itemType == ItemType.NATIVE) {
                    // Ensure that sufficient native tokens are still available.
                    if (amount > etherRemaining) {
                        revert InsufficientEtherSupplied();
                    }

                    // Skip underflow check as a comparison has just been made.
                    etherRemaining -= amount;
                }

                // Transfer item from caller to recipient specified by the item.
                _transferConsiderationItem(
                    considerationItem,
                    msg.sender,
                    fulfillerConduitKey,
                    accumulator
                );
            }
        }

        // Trigger any remaining accumulated transfers via call to the conduit.
        _triggerIfArmed(accumulator);

        // If any ether remains after fulfillments...
        if (etherRemaining != 0) {
            // return it to the caller.
            _transferEth(payable(msg.sender), etherRemaining);
        }
    }

    /**
     * @dev Internal function to emit an OrderFulfilled event. OfferItems are
     *      translated into SpentItems and ConsiderationItems are translated
     *      into ReceivedItems.
     *
     * @param orderHash     The order hash.
     * @param offerer       The offerer for the order.
     * @param zone          The zone for the order.
     * @param fulfiller     The fulfiller of the order, or the null address if
     *                      the order was fulfilled via order matching.
     * @param offer         The offer items for the order.
     * @param consideration The consideration items for the order.
     */
    function _emitOrderFulfilledEvent(
        bytes32 orderHash,
        address offerer,
        address zone,
        address fulfiller,
        OfferItem[] memory offer,
        ConsiderationItem[] memory consideration
    ) internal {
        // Cast already-modified offer memory region as spent items.
        SpentItem[] memory spentItems;
        assembly {
            spentItems := offer
        }

        // Cast already-modified consideration memory region as received items.
        ReceivedItem[] memory receivedItems;
        assembly {
            receivedItems := consideration
        }

        // Emit an event signifying that the order has been fulfilled.
        emit OrderFulfilled(
            orderHash,
            offerer,
            zone,
            fulfiller,
            spentItems,
            receivedItems
        );
    }

    /**
     * @dev Internal pure function to convert an order to an advanced order with
     *      numerator and denominator of 1 and empty extraData.
     *
     * @param order The order to convert.
     *
     * @return advancedOrder The new advanced order.
     */
    function _convertOrderToAdvanced(Order calldata order)
        internal
        pure
        returns (AdvancedOrder memory advancedOrder)
    {
        // Convert to partial order (1/1 or full fill) and return new value.
        advancedOrder = AdvancedOrder(
            order.parameters,
            1,
            1,
            order.signature,
            ""
        );
    }

    /**
     * @dev Internal pure function to convert an array of orders to an array of
     *      advanced orders with numerator and denominator of 1.
     *
     * @param orders The orders to convert.
     *
     * @return advancedOrders The new array of partial orders.
     */
    function _convertOrdersToAdvanced(Order[] calldata orders)
        internal
        pure
        returns (AdvancedOrder[] memory advancedOrders)
    {
        // Read the number of orders from calldata and place on the stack.
        uint256 totalOrders = orders.length;

        // Allocate new empty array for each partial order in memory.
        advancedOrders = new AdvancedOrder[](totalOrders);

        // Skip overflow check as the index for the loop starts at zero.
        unchecked {
            // Iterate over the given orders.
            for (uint256 i = 0; i < totalOrders; ++i) {
                // Convert to partial order (1/1 or full fill) and update array.
                advancedOrders[i] = _convertOrderToAdvanced(orders[i]);
            }
        }

        // Return the array of advanced orders.
        return advancedOrders;
    }
}

OrderFulfiller.sol

OrderValidator.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

/**
 * @title ReentrancyErrors
 * @author 0age
 * @notice ReentrancyErrors contains errors related to reentrancy.
 */
interface ReentrancyErrors {
    /**
     * @dev Revert with an error when a caller attempts to reenter a protected
     *      function.
     */
    error NoReentrantCalls();
}

ReentrancyErrors.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.13;

import { ReentrancyErrors } from "ReentrancyErrors.sol";

import "ConsiderationConstants.sol";

/**
 * @title ReentrancyGuard
 * @author 0age
 * @notice ReentrancyGuard contains a storage variable and related functionality
 *         for protecting against reentrancy.
 */
contract ReentrancyGuard is ReentrancyErrors {
    // Prevent reentrant calls on protected functions.
    uint256 private _reentrancyGuard;

    /**
     * @dev Initialize the reentrancy guard during deployment.
     */
    constructor() {
        // Initialize the reentrancy guard in a cleared state.
        _reentrancyGuard = _NOT_ENTERED;
    }

    /**
     * @dev Internal function to ensure that the sentinel value for the
     *      reentrancy guard is not currently set and, if not, to set the
     *      sentinel value for the reentrancy guard.
     */
    function _setReentrancyGuard() internal {
        // Ensure that the reentrancy guard is not already set.
        _assertNonReentrant();

        // Set the reentrancy guard.
        _reentrancyGuard = _ENTERED;
    }

    /**
     * @dev Internal function to unset the reentrancy guard sentinel value.
     */
    function _clearReentrancyGuard() internal {
        // Clear the reentrancy guard.
        _reentrancyGuard = _NOT_ENTERED;
    }

    /**
     * @dev Internal view function to ensure that the sentinel value for the
            reentrancy guard is not currently set.
     */
    function _assertNonReentrant() internal view {
        // Ensure that the reentrancy guard is not currently set.
        if (_reentrancyGuard != _NOT_ENTERED) {
            revert NoReentrantCalls();
        }
    }
}

ReentrancyGuard.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.13;

import { Consideration } from "Consideration.sol";

/**
 * @title Seaport
 * @custom:version 1.1
 * @author 0age (0age.eth)
 * @custom:coauthor d1ll0n (d1ll0n.eth)
 * @custom:coauthor transmissions11 (t11s.eth)
 * @custom:contributor Kartik (slokh.eth)
 * @custom:contributor LeFevre (lefevre.eth)
 * @custom:contributor Joseph Schiarizzi (CupOJoseph.eth)
 * @custom:contributor Aspyn Palatnick (stuckinaboot.eth)
 * @custom:contributor James Wenzel (emo.eth)
 * @custom:contributor Stephan Min (stephanm.eth)
 * @custom:contributor Ryan Ghods (ralxz.eth)
 * @custom:contributor hack3r-0m (hack3r-0m.eth)
 * @custom:contributor Diego Estevez (antidiego.eth)
 * @custom:contributor Chomtana (chomtana.eth)
 * @custom:contributor Saw-mon and Natalie (sawmonandnatalie.eth)
 * @custom:contributor 0xBeans (0xBeans.eth)
 * @custom:contributor 0x4non (punkdev.eth)
 * @custom:contributor Laurence E. Day (norsefire.eth)
 * @custom:contributor vectorized.eth (vectorized.eth)
 * @custom:contributor karmacoma (karmacoma.eth)
 * @custom:contributor horsefacts (horsefacts.eth)
 * @custom:contributor UncarvedBlock (uncarvedblock.eth)
 * @custom:contributor Zoraiz Mahmood (zorz.eth)
 * @custom:contributor William Poulin (wpoulin.eth)
 * @custom:contributor Rajiv Patel-O'Connor (rajivpoc.eth)
 * @custom:contributor tserg (tserg.eth)
 * @custom:contributor cygaar (cygaar.eth)
 * @custom:contributor Meta0xNull (meta0xnull.eth)
 * @custom:contributor gpersoon (gpersoon.eth)
 * @custom:contributor Matt Solomon (msolomon.eth)
 * @custom:contributor Weikang Song (weikangs.eth)
 * @custom:contributor zer0dot (zer0dot.eth)
 * @custom:contributor Mudit Gupta (mudit.eth)
 * @custom:contributor leonardoalt (leoalt.eth)
 * @custom:contributor cmichel (cmichel.eth)
 * @custom:contributor PraneshASP (pranesh.eth)
 * @custom:contributor JasperAlexander (jasperalexander.eth)
 * @custom:contributor Ellahi (ellahi.eth)
 * @custom:contributor zaz (1zaz1.eth)
 * @custom:contributor berndartmueller (berndartmueller.eth)
 * @custom:contributor dmfxyz (dmfxyz.eth)
 * @custom:contributor daltoncoder (dontkillrobots.eth)
 * @custom:contributor 0xf4ce (0xf4ce.eth)
 * @custom:contributor phaze (phaze.eth)
 * @custom:contributor hrkrshnn (hrkrshnn.eth)
 * @custom:contributor axic (axic.eth)
 * @custom:contributor leastwood (leastwood.eth)
 * @custom:contributor 0xsanson (sanson.eth)
 * @custom:contributor blockdev (blockd3v.eth)
 * @custom:contributor fiveoutofnine (fiveoutofnine.eth)
 * @custom:contributor shuklaayush (shuklaayush.eth)
 * @custom:contributor 0xPatissier
 * @custom:contributor pcaversaccio
 * @custom:contributor David Eiber
 * @custom:contributor csanuragjain
 * @custom:contributor sach1r0
 * @custom:contributor twojoy0
 * @custom:contributor ori_dabush
 * @custom:contributor Daniel Gelfand
 * @custom:contributor okkothejawa
 * @custom:contributor FlameHorizon
 * @custom:contributor vdrg
 * @custom:contributor dmitriia
 * @custom:contributor bokeh-eth
 * @custom:contributor asutorufos
 * @custom:contributor rfart(rfa)
 * @custom:contributor Riley Holterhus
 * @custom:contributor big-tech-sux
 * @notice Seaport is a generalized ETH/ERC20/ERC721/ERC1155 marketplace. It
 *         minimizes external calls to the greatest extent possible and provides
 *         lightweight methods for common routes as well as more flexible
 *         methods for composing advanced orders or groups of orders. Each order
 *         contains an arbitrary number of items that may be spent (the "offer")
 *         along with an arbitrary number of items that must be received back by
 *         the indicated recipients (the "consideration").
 */
contract Seaport is Consideration {
    /**
     * @notice Derive and set hashes, reference chainId, and associated domain
     *         separator during deployment.
     *
     * @param conduitController A contract that deploys conduits, or proxies
     *                          that may optionally be used to transfer approved
     *                          ERC20/721/1155 tokens.
     */
    constructor(address conduitController) Consideration(conduitController) {}

    /**
     * @dev Internal pure function to retrieve and return the name of this
     *      contract.
     *
     * @return The name of this contract.
     */
    function _name() internal pure override returns (string memory) {
        // Return the name of the contract.
        assembly {
            mstore(0x20, 0x20)
            mstore(0x47, 0x07536561706f7274)
            return(0x20, 0x60)
        }
    }

    /**
     * @dev Internal pure function to retrieve the name of this contract as a
     *      string that will be used to derive the name hash in the constructor.
     *
     * @return The name of this contract as a string.
     */
    function _nameString() internal pure override returns (string memory) {
        // Return the name of the contract.
        return "Seaport";
    }
}

Seaport.sol

SeaportInterface.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.13;

import { EIP1271Interface } from "EIP1271Interface.sol";

// prettier-ignore
import {
    SignatureVerificationErrors
} from "SignatureVerificationErrors.sol";

import { LowLevelHelpers } from "LowLevelHelpers.sol";

import "ConsiderationConstants.sol";

/**
 * @title SignatureVerification
 * @author 0age
 * @notice SignatureVerification contains logic for verifying signatures.
 */
contract SignatureVerification is SignatureVerificationErrors, LowLevelHelpers {
    /**
     * @dev Internal view function to verify the signature of an order. An
     *      ERC-1271 fallback will be attempted if either the signature length
     *      is not 64 or 65 bytes or if the recovered signer does not match the
     *      supplied signer.
     *
     * @param signer    The signer for the order.
     * @param digest    The digest to verify the signature against.
     * @param signature A signature from the signer indicating that the order
     *                  has been approved.
     */
    function _assertValidSignature(
        address signer,
        bytes32 digest,
        bytes memory signature
    ) internal view {
        // Declare value for ecrecover equality or 1271 call success status.
        bool success;

        // Utilize assembly to perform optimized signature verification check.
        assembly {
            // Ensure that first word of scratch space is empty.
            mstore(0, 0)

            // Declare value for v signature parameter.
            let v

            // Get the length of the signature.
            let signatureLength := mload(signature)

            // Get the pointer to the value preceding the signature length.
            // This will be used for temporary memory overrides - either the
            // signature head for isValidSignature or the digest for ecrecover.
            let wordBeforeSignaturePtr := sub(signature, OneWord)

            // Cache the current value behind the signature to restore it later.
            let cachedWordBeforeSignature := mload(wordBeforeSignaturePtr)

            // Declare lenDiff + recoveredSigner scope to manage stack pressure.
            {
                // Take the difference between the max ECDSA signature length
                // and the actual signature length. Overflow desired for any
                // values > 65. If the diff is not 0 or 1, it is not a valid
                // ECDSA signature - move on to EIP1271 check.
                let lenDiff := sub(ECDSA_MaxLength, signatureLength)

                // Declare variable for recovered signer.
                let recoveredSigner

                // If diff is 0 or 1, it may be an ECDSA signature.
                // Try to recover signer.
                if iszero(gt(lenDiff, 1)) {
                    // Read the signature `s` value.
                    let originalSignatureS := mload(
                        add(signature, ECDSA_signature_s_offset)
                    )

                    // Read the first byte of the word after `s`. If the
                    // signature is 65 bytes, this will be the real `v` value.
                    // If not, it will need to be modified - doing it this way
                    // saves an extra condition.
                    v := byte(
                        0,
                        mload(add(signature, ECDSA_signature_v_offset))
                    )

                    // If lenDiff is 1, parse 64-byte signature as ECDSA.
                    if lenDiff {
                        // Extract yParity from highest bit of vs and add 27 to
                        // get v.
                        v := add(
                            shr(MaxUint8, originalSignatureS),
                            Signature_lower_v
                        )

                        // Extract canonical s from vs, all but the highest bit.
                        // Temporarily overwrite the original `s` value in the
                        // signature.
                        mstore(
                            add(signature, ECDSA_signature_s_offset),
                            and(
                                originalSignatureS,
                                EIP2098_allButHighestBitMask
                            )
                        )
                    }
                    // Temporarily overwrite the signature length with `v` to
                    // conform to the expected input for ecrecover.
                    mstore(signature, v)

                    // Temporarily overwrite the word before the length with
                    // `digest` to conform to the expected input for ecrecover.
                    mstore(wordBeforeSignaturePtr, digest)

                    // Attempt to recover the signer for the given signature. Do
                    // not check the call status as ecrecover will return a null
                    // address if the signature is invalid.
                    pop(
                        staticcall(
                            gas(),
                            Ecrecover_precompile, // Call ecrecover precompile.
                            wordBeforeSignaturePtr, // Use data memory location.
                            Ecrecover_args_size, // Size of digest, v, r, and s.
                            0, // Write result to scratch space.
                            OneWord // Provide size of returned result.
                        )
                    )

                    // Restore cached word before signature.
                    mstore(wordBeforeSignaturePtr, cachedWordBeforeSignature)

                    // Restore cached signature length.
                    mstore(signature, signatureLength)

                    // Restore cached signature `s` value.
                    mstore(
                        add(signature, ECDSA_signature_s_offset),
                        originalSignatureS
                    )

                    // Read the recovered signer from the buffer given as return
                    // space for ecrecover.
                    recoveredSigner := mload(0)
                }

                // Set success to true if the signature provided was a valid
                // ECDSA signature and the signer is not the null address. Use
                // gt instead of direct as success is used outside of assembly.
                success := and(eq(signer, recoveredSigner), gt(signer, 0))
            }

            // If the signature was not verified with ecrecover, try EIP1271.
            if iszero(success) {
                // Temporarily overwrite the word before the signature length
                // and use it as the head of the signature input to
                // `isValidSignature`, which has a value of 64.
                mstore(
                    wordBeforeSignaturePtr,
                    EIP1271_isValidSignature_signature_head_offset
                )

                // Get pointer to use for the selector of `isValidSignature`.
                let selectorPtr := sub(
                    signature,
                    EIP1271_isValidSignature_selector_negativeOffset
                )

                // Cache the value currently stored at the selector pointer.
                let cachedWordOverwrittenBySelector := mload(selectorPtr)

                // Get pointer to use for `digest` input to `isValidSignature`.
                let digestPtr := sub(
                    signature,
                    EIP1271_isValidSignature_digest_negativeOffset
                )

                // Cache the value currently stored at the digest pointer.
                let cachedWordOverwrittenByDigest := mload(digestPtr)

                // Write the selector first, since it overlaps the digest.
                mstore(selectorPtr, EIP1271_isValidSignature_selector)

                // Next, write the digest.
                mstore(digestPtr, digest)

                // Call signer with `isValidSignature` to validate signature.
                success := staticcall(
                    gas(),
                    signer,
                    selectorPtr,
                    add(
                        signatureLength,
                        EIP1271_isValidSignature_calldata_baseLength
                    ),
                    0,
                    OneWord
                )

                // Determine if the signature is valid on successful calls.
                if success {
                    // If first word of scratch space does not contain EIP-1271
                    // signature selector, revert.
                    if iszero(eq(mload(0), EIP1271_isValidSignature_selector)) {
                        // Revert with bad 1271 signature if signer has code.
                        if extcodesize(signer) {
                            // Bad contract signature.
                            mstore(0, BadContractSignature_error_signature)
                            revert(0, BadContractSignature_error_length)
                        }

                        // Check if signature length was invalid.
                        if gt(sub(ECDSA_MaxLength, signatureLength), 1) {
                            // Revert with generic invalid signature error.
                            mstore(0, InvalidSignature_error_signature)
                            revert(0, InvalidSignature_error_length)
                        }

                        // Check if v was invalid.
                        if iszero(
                            byte(v, ECDSA_twentySeventhAndTwentyEighthBytesSet)
                        ) {
                            // Revert with invalid v value.
                            mstore(0, BadSignatureV_error_signature)
                            mstore(BadSignatureV_error_offset, v)
                            revert(0, BadSignatureV_error_length)
                        }

                        // Revert with generic invalid signer error message.
                        mstore(0, InvalidSigner_error_signature)
                        revert(0, InvalidSigner_error_length)
                    }
                }

                // Restore the cached values overwritten by selector, digest and
                // signature head.
                mstore(wordBeforeSignaturePtr, cachedWordBeforeSignature)
                mstore(selectorPtr, cachedWordOverwrittenBySelector)
                mstore(digestPtr, cachedWordOverwrittenByDigest)
            }
        }

        // If the call failed...
        if (!success) {
            // Revert and pass reason along if one was returned.
            _revertWithReasonIfOneIsReturned();

            // Otherwise, revert with error indicating bad contract signature.
            assembly {
                mstore(0, BadContractSignature_error_signature)
                revert(0, BadContractSignature_error_length)
            }
        }
    }
}

SignatureVerification.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

/**
 * @title SignatureVerificationErrors
 * @author 0age
 * @notice SignatureVerificationErrors contains all errors related to signature
 *         verification.
 */
interface SignatureVerificationErrors {
    /**
     * @dev Revert with an error when a signature that does not contain a v
     *      value of 27 or 28 has been supplied.
     *
     * @param v The invalid v value.
     */
    error BadSignatureV(uint8 v);

    /**
     * @dev Revert with an error when the signer recovered by the supplied
     *      signature does not match the offerer or an allowed EIP-1271 signer
     *      as specified by the offerer in the event they are a contract.
     */
    error InvalidSigner();

    /**
     * @dev Revert with an error when a signer cannot be recovered from the
     *      supplied signature.
     */
    error InvalidSignature();

    /**
     * @dev Revert with an error when an EIP-1271 call to an account fails.
     */
    error BadContractSignature();
}

SignatureVerificationErrors.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

import { ZoneInterface } from "ZoneInterface.sol";

// prettier-ignore
import {
    AdvancedOrder,
    CriteriaResolver
} from "ConsiderationStructs.sol";

contract TestZone is ZoneInterface {
    function isValidOrder(
        bytes32 orderHash,
        address caller,
        address offerer,
        bytes32 zoneHash
    ) external pure override returns (bytes4 validOrderMagicValue) {
        orderHash;
        caller;
        offerer;

        if (zoneHash == bytes32(uint256(1))) {
            revert("Revert on zone hash 1");
        } else if (zoneHash == bytes32(uint256(2))) {
            assembly {
                revert(0, 0)
            }
        }

        validOrderMagicValue = zoneHash != bytes32(uint256(3))
            ? ZoneInterface.isValidOrder.selector
            : bytes4(0xffffffff);
    }

    function isValidOrderIncludingExtraData(
        bytes32 orderHash,
        address caller,
        AdvancedOrder calldata order,
        bytes32[] calldata priorOrderHashes,
        CriteriaResolver[] calldata criteriaResolvers
    ) external pure override returns (bytes4 validOrderMagicValue) {
        orderHash;
        caller;
        order;
        priorOrderHashes;
        criteriaResolvers;

        if (order.extraData.length == 4) {
            revert("Revert on extraData length 4");
        } else if (order.extraData.length == 5) {
            assembly {
                revert(0, 0)
            }
        }

        validOrderMagicValue = order.parameters.zoneHash != bytes32(uint256(3))
            ? ZoneInterface.isValidOrder.selector
            : bytes4(0xffffffff);
    }
}

TestZone.sol

TokenTransferrer.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

/*
 * -------------------------- Disambiguation & Other Notes ---------------------
 *    - The term "head" is used as it is in the documentation for ABI encoding,
 *      but only in reference to dynamic types, i.e. it always refers to the
 *      offset or pointer to the body of a dynamic type. In calldata, the head
 *      is always an offset (relative to the parent object), while in memory,
 *      the head is always the pointer to the body. More information found here:
 *      https://docs.soliditylang.org/en/v0.8.14/abi-spec.html#argument-encoding
 *        - Note that the length of an array is separate from and precedes the
 *          head of the array.
 *
 *    - The term "body" is used in place of the term "head" used in the ABI
 *      documentation. It refers to the start of the data for a dynamic type,
 *      e.g. the first word of a struct or the first word of the first element
 *      in an array.
 *
 *    - The term "pointer" is used to describe the absolute position of a value
 *      and never an offset relative to another value.
 *        - The suffix "_ptr" refers to a memory pointer.
 *        - The suffix "_cdPtr" refers to a calldata pointer.
 *
 *    - The term "offset" is used to describe the position of a value relative
 *      to some parent value. For example, OrderParameters_conduit_offset is the
 *      offset to the "conduit" value in the OrderParameters struct relative to
 *      the start of the body.
 *        - Note: Offsets are used to derive pointers.
 *
 *    - Some structs have pointers defined for all of their fields in this file.
 *      Lines which are commented out are fields that are not used in the
 *      codebase but have been left in for readability.
 */

uint256 constant AlmostOneWord = 0x1f;
uint256 constant OneWord = 0x20;
uint256 constant TwoWords = 0x40;
uint256 constant ThreeWords = 0x60;

uint256 constant FreeMemoryPointerSlot = 0x40;
uint256 constant ZeroSlot = 0x60;
uint256 constant DefaultFreeMemoryPointer = 0x80;

uint256 constant Slot0x80 = 0x80;
uint256 constant Slot0xA0 = 0xa0;
uint256 constant Slot0xC0 = 0xc0;

// abi.encodeWithSignature("transferFrom(address,address,uint256)")
uint256 constant ERC20_transferFrom_signature = (
    0x23b872dd00000000000000000000000000000000000000000000000000000000
);
uint256 constant ERC20_transferFrom_sig_ptr = 0x0;
uint256 constant ERC20_transferFrom_from_ptr = 0x04;
uint256 constant ERC20_transferFrom_to_ptr = 0x24;
uint256 constant ERC20_transferFrom_amount_ptr = 0x44;
uint256 constant ERC20_transferFrom_length = 0x64; // 4 + 32 * 3 == 100

// abi.encodeWithSignature(
//     "safeTransferFrom(address,address,uint256,uint256,bytes)"
// )
uint256 constant ERC1155_safeTransferFrom_signature = (
    0xf242432a00000000000000000000000000000000000000000000000000000000
);
uint256 constant ERC1155_safeTransferFrom_sig_ptr = 0x0;
uint256 constant ERC1155_safeTransferFrom_from_ptr = 0x04;
uint256 constant ERC1155_safeTransferFrom_to_ptr = 0x24;
uint256 constant ERC1155_safeTransferFrom_id_ptr = 0x44;
uint256 constant ERC1155_safeTransferFrom_amount_ptr = 0x64;
uint256 constant ERC1155_safeTransferFrom_data_offset_ptr = 0x84;
uint256 constant ERC1155_safeTransferFrom_data_length_ptr = 0xa4;
uint256 constant ERC1155_safeTransferFrom_length = 0xc4; // 4 + 32 * 6 == 196
uint256 constant ERC1155_safeTransferFrom_data_length_offset = 0xa0;

// abi.encodeWithSignature(
//     "safeBatchTransferFrom(address,address,uint256[],uint256[],bytes)"
// )
uint256 constant ERC1155_safeBatchTransferFrom_signature = (
    0x2eb2c2d600000000000000000000000000000000000000000000000000000000
);

bytes4 constant ERC1155_safeBatchTransferFrom_selector = bytes4(
    bytes32(ERC1155_safeBatchTransferFrom_signature)
);

uint256 constant ERC721_transferFrom_signature = ERC20_transferFrom_signature;
uint256 constant ERC721_transferFrom_sig_ptr = 0x0;
uint256 constant ERC721_transferFrom_from_ptr = 0x04;
uint256 constant ERC721_transferFrom_to_ptr = 0x24;
uint256 constant ERC721_transferFrom_id_ptr = 0x44;
uint256 constant ERC721_transferFrom_length = 0x64; // 4 + 32 * 3 == 100

// abi.encodeWithSignature("NoContract(address)")
uint256 constant NoContract_error_signature = (
    0x5f15d67200000000000000000000000000000000000000000000000000000000
);
uint256 constant NoContract_error_sig_ptr = 0x0;
uint256 constant NoContract_error_token_ptr = 0x4;
uint256 constant NoContract_error_length = 0x24; // 4 + 32 == 36

// abi.encodeWithSignature(
//     "TokenTransferGenericFailure(address,address,address,uint256,uint256)"
// )
uint256 constant TokenTransferGenericFailure_error_signature = (
    0xf486bc8700000000000000000000000000000000000000000000000000000000
);
uint256 constant TokenTransferGenericFailure_error_sig_ptr = 0x0;
uint256 constant TokenTransferGenericFailure_error_token_ptr = 0x4;
uint256 constant TokenTransferGenericFailure_error_from_ptr = 0x24;
uint256 constant TokenTransferGenericFailure_error_to_ptr = 0x44;
uint256 constant TokenTransferGenericFailure_error_id_ptr = 0x64;
uint256 constant TokenTransferGenericFailure_error_amount_ptr = 0x84;

// 4 + 32 * 5 == 164
uint256 constant TokenTransferGenericFailure_error_length = 0xa4;

// abi.encodeWithSignature(
//     "BadReturnValueFromERC20OnTransfer(address,address,address,uint256)"
// )
uint256 constant BadReturnValueFromERC20OnTransfer_error_signature = (
    0x9889192300000000000000000000000000000000000000000000000000000000
);
uint256 constant BadReturnValueFromERC20OnTransfer_error_sig_ptr = 0x0;
uint256 constant BadReturnValueFromERC20OnTransfer_error_token_ptr = 0x4;
uint256 constant BadReturnValueFromERC20OnTransfer_error_from_ptr = 0x24;
uint256 constant BadReturnValueFromERC20OnTransfer_error_to_ptr = 0x44;
uint256 constant BadReturnValueFromERC20OnTransfer_error_amount_ptr = 0x64;

// 4 + 32 * 4 == 132
uint256 constant BadReturnValueFromERC20OnTransfer_error_length = 0x84;

uint256 constant ExtraGasBuffer = 0x20;
uint256 constant CostPerWord = 3;
uint256 constant MemoryExpansionCoefficient = 0x200;

// Values are offset by 32 bytes in order to write the token to the beginning
// in the event of a revert
uint256 constant BatchTransfer1155Params_ptr = 0x24;
uint256 constant BatchTransfer1155Params_ids_head_ptr = 0x64;
uint256 constant BatchTransfer1155Params_amounts_head_ptr = 0x84;
uint256 constant BatchTransfer1155Params_data_head_ptr = 0xa4;
uint256 constant BatchTransfer1155Params_data_length_basePtr = 0xc4;
uint256 constant BatchTransfer1155Params_calldata_baseSize = 0xc4;

uint256 constant BatchTransfer1155Params_ids_length_ptr = 0xc4;

uint256 constant BatchTransfer1155Params_ids_length_offset = 0xa0;
uint256 constant BatchTransfer1155Params_amounts_length_baseOffset = 0xc0;
uint256 constant BatchTransfer1155Params_data_length_baseOffset = 0xe0;

uint256 constant ConduitBatch1155Transfer_usable_head_size = 0x80;

uint256 constant ConduitBatch1155Transfer_from_offset = 0x20;
uint256 constant ConduitBatch1155Transfer_ids_head_offset = 0x60;
uint256 constant ConduitBatch1155Transfer_amounts_head_offset = 0x80;
uint256 constant ConduitBatch1155Transfer_ids_length_offset = 0xa0;
uint256 constant ConduitBatch1155Transfer_amounts_length_baseOffset = 0xc0;
uint256 constant ConduitBatch1155Transfer_calldata_baseSize = 0xc0;

// Note: abbreviated version of above constant to adhere to line length limit.
uint256 constant ConduitBatchTransfer_amounts_head_offset = 0x80;

uint256 constant Invalid1155BatchTransferEncoding_ptr = 0x00;
uint256 constant Invalid1155BatchTransferEncoding_length = 0x04;
uint256 constant Invalid1155BatchTransferEncoding_selector = (
    0xeba2084c00000000000000000000000000000000000000000000000000000000
);

uint256 constant ERC1155BatchTransferGenericFailure_error_signature = (
    0xafc445e200000000000000000000000000000000000000000000000000000000
);
uint256 constant ERC1155BatchTransferGenericFailure_token_ptr = 0x04;
uint256 constant ERC1155BatchTransferGenericFailure_ids_offset = 0xc0;

TokenTransferrerConstants.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

/**
 * @title TokenTransferrerErrors
 */
interface TokenTransferrerErrors {
    /**
     * @dev Revert with an error when an ERC721 transfer with amount other than
     *      one is attempted.
     */
    error InvalidERC721TransferAmount();

    /**
     * @dev Revert with an error when attempting to fulfill an order where an
     *      item has an amount of zero.
     */
    error MissingItemAmount();

    /**
     * @dev Revert with an error when attempting to fulfill an order where an
     *      item has unused parameters. This includes both the token and the
     *      identifier parameters for native transfers as well as the identifier
     *      parameter for ERC20 transfers. Note that the conduit does not
     *      perform this check, leaving it up to the calling channel to enforce
     *      when desired.
     */
    error UnusedItemParameters();

    /**
     * @dev Revert with an error when an ERC20, ERC721, or ERC1155 token
     *      transfer reverts.
     *
     * @param token      The token for which the transfer was attempted.
     * @param from       The source of the attempted transfer.
     * @param to         The recipient of the attempted transfer.
     * @param identifier The identifier for the attempted transfer.
     * @param amount     The amount for the attempted transfer.
     */
    error TokenTransferGenericFailure(
        address token,
        address from,
        address to,
        uint256 identifier,
        uint256 amount
    );

    /**
     * @dev Revert with an error when a batch ERC1155 token transfer reverts.
     *
     * @param token       The token for which the transfer was attempted.
     * @param from        The source of the attempted transfer.
     * @param to          The recipient of the attempted transfer.
     * @param identifiers The identifiers for the attempted transfer.
     * @param amounts     The amounts for the attempted transfer.
     */
    error ERC1155BatchTransferGenericFailure(
        address token,
        address from,
        address to,
        uint256[] identifiers,
        uint256[] amounts
    );

    /**
     * @dev Revert with an error when an ERC20 token transfer returns a falsey
     *      value.
     *
     * @param token      The token for which the ERC20 transfer was attempted.
     * @param from       The source of the attempted ERC20 transfer.
     * @param to         The recipient of the attempted ERC20 transfer.
     * @param amount     The amount for the attempted ERC20 transfer.
     */
    error BadReturnValueFromERC20OnTransfer(
        address token,
        address from,
        address to,
        uint256 amount
    );

    /**
     * @dev Revert with an error when an account being called as an assumed
     *      contract does not have code and returns no data.
     *
     * @param account The account that should contain code.
     */
    error NoContract(address account);

    /**
     * @dev Revert with an error when attempting to execute an 1155 batch
     *      transfer using calldata not produced by default ABI encoding or with
     *      different lengths for ids and amounts arrays.
     */
    error Invalid1155BatchTransferEncoding();
}

TokenTransferrerErrors.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

import "TransferHelperStructs.sol";

import { TokenTransferrer } from "TokenTransferrer.sol";

import { ConduitInterface } from "ConduitInterface.sol";

// prettier-ignore
import {
    ConduitControllerInterface
} from "ConduitControllerInterface.sol";

import { Conduit } from "Conduit.sol";

import { ConduitTransfer } from "ConduitStructs.sol";

// prettier-ignore
import {
    TransferHelperInterface
} from "TransferHelperInterface.sol";

/**
 * @title TransferHelper
 * @author stuckinaboot, stephankmin
 * @notice TransferHelper is a utility contract for transferring
 *         ERC20/ERC721/ERC1155 items in bulk to a specific recipient.
 */
contract TransferHelper is TransferHelperInterface, TokenTransferrer {
    // Allow for interaction with the conduit controller.
    ConduitControllerInterface internal immutable _CONDUIT_CONTROLLER;

    // Cache the conduit creation hash used by the conduit controller.
    bytes32 internal immutable _CONDUIT_CREATION_CODE_HASH;

    /**
     * @dev Set the supplied conduit controller and retrieve its
     *      conduit creation code hash.
     *
     *
     * @param conduitController A contract that deploys conduits, or proxies
     *                          that may optionally be used to transfer approved
     *                          ERC20/721/1155 tokens.
     */
    constructor(address conduitController) {
        // Get the conduit creation code hash from the supplied conduit
        // controller and set it as an immutable.
        ConduitControllerInterface controller = ConduitControllerInterface(
            conduitController
        );
        (_CONDUIT_CREATION_CODE_HASH, ) = controller.getConduitCodeHashes();

        // Set the supplied conduit controller as an immutable.
        _CONDUIT_CONTROLLER = controller;
    }

    /**
     * @notice Transfer multiple items to a single recipient.
     *
     * @param items      The items to transfer.
     * @param recipient  The address the items should be transferred to.
     * @param conduitKey The key of the conduit through which the bulk transfer
     *                   should occur.
     *
     * @return magicValue A value indicating that the transfers were successful.
     */
    function bulkTransfer(
        TransferHelperItem[] calldata items,
        address recipient,
        bytes32 conduitKey
    ) external override returns (bytes4 magicValue) {
        // Retrieve total number of transfers and place on stack.
        uint256 totalTransfers = items.length;

        // If no conduitKey is given, use TokenTransferrer to perform transfers.
        if (conduitKey == bytes32(0)) {
            // Skip overflow checks: all for loops are indexed starting at zero.
            unchecked {
                // Iterate over each transfer.
                for (uint256 i = 0; i < totalTransfers; ++i) {
                    // Retrieve the transfer in question.
                    TransferHelperItem calldata item = items[i];

                    // Perform a transfer based on the transfer's item type.
                    // Revert if item being transferred is a native token.
                    if (item.itemType == ConduitItemType.NATIVE) {
                        revert InvalidItemType();
                    } else if (item.itemType == ConduitItemType.ERC20) {
                        _performERC20Transfer(
                            item.token,
                            msg.sender,
                            recipient,
                            item.amount
                        );
                    } else if (item.itemType == ConduitItemType.ERC721) {
                        _performERC721Transfer(
                            item.token,
                            msg.sender,
                            recipient,
                            item.identifier
                        );
                    } else {
                        _performERC1155Transfer(
                            item.token,
                            msg.sender,
                            recipient,
                            item.identifier,
                            item.amount
                        );
                    }
                }
            }
        }
        // Otherwise, a conduitKey was provided.
        else {
            // Derive the conduit address from the deployer, conduit key
            // and creation code hash.
            address conduit = address(
                uint160(
                    uint256(
                        keccak256(
                            abi.encodePacked(
                                bytes1(0xff),
                                address(_CONDUIT_CONTROLLER),
                                conduitKey,
                                _CONDUIT_CREATION_CODE_HASH
                            )
                        )
                    )
                )
            );

            // Declare a new array to populate with each token transfer.
            ConduitTransfer[] memory conduitTransfers = new ConduitTransfer[](
                totalTransfers
            );

            // Skip overflow checks: all for loops are indexed starting at zero.
            unchecked {
                // Iterate over each transfer.
                for (uint256 i = 0; i < totalTransfers; ++i) {
                    // Retrieve the transfer in question.
                    TransferHelperItem calldata item = items[i];

                    // Create a ConduitTransfer corresponding to each
                    // TransferHelperItem.
                    conduitTransfers[i] = ConduitTransfer(
                        item.itemType,
                        item.token,
                        msg.sender,
                        recipient,
                        item.identifier,
                        item.amount
                    );
                }
            }

            // Call the conduit and execute bulk transfers.
            ConduitInterface(conduit).execute(conduitTransfers);
        }

        // Return a magic value indicating that the transfers were performed.
        magicValue = this.bulkTransfer.selector;
    }
}

TransferHelper.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

import { TransferHelperItem } from "TransferHelperStructs.sol";

interface TransferHelperInterface {
    /**
     * @dev Revert with an error when attempting to execute transfers with a
     *      NATIVE itemType.
     */
    error InvalidItemType();

    /**
     * @notice Transfer multiple items to a single recipient.
     *
     * @param items The items to transfer.
     * @param recipient  The address the items should be transferred to.
     * @param conduitKey  The key of the conduit performing the bulk transfer.
     */
    function bulkTransfer(
        TransferHelperItem[] calldata items,
        address recipient,
        bytes32 conduitKey
    ) external returns (bytes4);
}

TransferHelperInterface.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

import { ConduitItemType } from "ConduitEnums.sol";

struct TransferHelperItem {
    ConduitItemType itemType;
    address token;
    uint256 identifier;
    uint256 amount;
}

TransferHelperStructs.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.13;

import { OrderStatus } from "ConsiderationStructs.sol";

import { Assertions } from "Assertions.sol";

import { SignatureVerification } from "SignatureVerification.sol";

/**
 * @title Verifiers
 * @author 0age
 * @notice Verifiers contains functions for performing verifications.
 */
contract Verifiers is Assertions, SignatureVerification {
    /**
     * @dev Derive and set hashes, reference chainId, and associated domain
     *      separator during deployment.
     *
     * @param conduitController A contract that deploys conduits, or proxies
     *                          that may optionally be used to transfer approved
     *                          ERC20/721/1155 tokens.
     */
    constructor(address conduitController) Assertions(conduitController) {}

    /**
     * @dev Internal view function to ensure that the current time falls within
     *      an order's valid timespan.
     *
     * @param startTime       The time at which the order becomes active.
     * @param endTime         The time at which the order becomes inactive.
     * @param revertOnInvalid A boolean indicating whether to revert if the
     *                        order is not active.
     *
     * @return valid A boolean indicating whether the order is active.
     */
    function _verifyTime(
        uint256 startTime,
        uint256 endTime,
        bool revertOnInvalid
    ) internal view returns (bool valid) {
        // Revert if order's timespan hasn't started yet or has already ended.
        if (startTime > block.timestamp || endTime <= block.timestamp) {
            // Only revert if revertOnInvalid has been supplied as true.
            if (revertOnInvalid) {
                revert InvalidTime();
            }

            // Return false as the order is invalid.
            return false;
        }

        // Return true as the order time is valid.
        valid = true;
    }

    /**
     * @dev Internal view function to verify the signature of an order. An
     *      ERC-1271 fallback will be attempted if either the signature length
     *      is not 32 or 33 bytes or if the recovered signer does not match the
     *      supplied offerer. Note that in cases where a 32 or 33 byte signature
     *      is supplied, only standard ECDSA signatures that recover to a
     *      non-zero address are supported.
     *
     * @param offerer   The offerer for the order.
     * @param orderHash The order hash.
     * @param signature A signature from the offerer indicating that the order
     *                  has been approved.
     */
    function _verifySignature(
        address offerer,
        bytes32 orderHash,
        bytes memory signature
    ) internal view {
        // Skip signature verification if the offerer is the caller.
        if (offerer == msg.sender) {
            return;
        }

        // Derive EIP-712 digest using the domain separator and the order hash.
        bytes32 digest = _deriveEIP712Digest(_domainSeparator(), orderHash);

        // Ensure that the signature for the digest is valid for the offerer.
        _assertValidSignature(offerer, digest, signature);
    }

    /**
     * @dev Internal view function to validate that a given order is fillable
     *      and not cancelled based on the order status.
     *
     * @param orderHash       The order hash.
     * @param orderStatus     The status of the order, including whether it has
     *                        been cancelled and the fraction filled.
     * @param onlyAllowUnused A boolean flag indicating whether partial fills
     *                        are supported by the calling function.
     * @param revertOnInvalid A boolean indicating whether to revert if the
     *                        order has been cancelled or filled beyond the
     *                        allowable amount.
     *
     * @return valid A boolean indicating whether the order is valid.
     */
    function _verifyOrderStatus(
        bytes32 orderHash,
        OrderStatus storage orderStatus,
        bool onlyAllowUnused,
        bool revertOnInvalid
    ) internal view returns (bool valid) {
        // Ensure that the order has not been cancelled.
        if (orderStatus.isCancelled) {
            // Only revert if revertOnInvalid has been supplied as true.
            if (revertOnInvalid) {
                revert OrderIsCancelled(orderHash);
            }

            // Return false as the order status is invalid.
            return false;
        }

        // Read order status numerator from storage and place on stack.
        uint256 orderStatusNumerator = orderStatus.numerator;

        // If the order is not entirely unused...
        if (orderStatusNumerator != 0) {
            // ensure the order has not been partially filled when not allowed.
            if (onlyAllowUnused) {
                // Always revert on partial fills when onlyAllowUnused is true.
                revert OrderPartiallyFilled(orderHash);
            }
            // Otherwise, ensure that order has not been entirely filled.
            else if (orderStatusNumerator >= orderStatus.denominator) {
                // Only revert if revertOnInvalid has been supplied as true.
                if (revertOnInvalid) {
                    revert OrderAlreadyFilled(orderHash);
                }

                // Return false as the order status is invalid.
                return false;
            }
        }

        // Return true as the order status is valid.
        valid = true;
    }
}

Verifiers.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.13;

import { ZoneInterface } from "ZoneInterface.sol";

import { OrderType } from "ConsiderationEnums.sol";

// prettier-ignore
import { AdvancedOrder, CriteriaResolver } from "ConsiderationStructs.sol";

import "ConsiderationConstants.sol";

// prettier-ignore
import {
    ZoneInteractionErrors
} from "ZoneInteractionErrors.sol";

import { LowLevelHelpers } from "LowLevelHelpers.sol";

/**
 * @title ZoneInteraction
 * @author 0age
 * @notice ZoneInteraction contains logic related to interacting with zones.
 */
contract ZoneInteraction is ZoneInteractionErrors, LowLevelHelpers {
    /**
     * @dev Internal view function to determine if an order has a restricted
     *      order type and, if so, to ensure that either the offerer or the zone
     *      are the fulfiller or that a staticcall to `isValidOrder` on the zone
     *      returns a magic value indicating that the order is currently valid.
     *
     * @param orderHash The hash of the order.
     * @param zoneHash  The hash to provide upon calling the zone.
     * @param orderType The type of the order.
     * @param offerer   The offerer in question.
     * @param zone      The zone in question.
     */
    function _assertRestrictedBasicOrderValidity(
        bytes32 orderHash,
        bytes32 zoneHash,
        OrderType orderType,
        address offerer,
        address zone
    ) internal view {
        // Order type 2-3 require zone or offerer be caller or zone to approve.
        if (
            uint256(orderType) > 1 &&
            msg.sender != zone &&
            msg.sender != offerer
        ) {
            // Perform minimal staticcall to the zone.
            _callIsValidOrder(zone, orderHash, offerer, zoneHash);
        }
    }

    function _callIsValidOrder(
        address zone,
        bytes32 orderHash,
        address offerer,
        bytes32 zoneHash
    ) internal view {
        // Perform minimal staticcall to the zone.
        bool success = _staticcall(
            zone,
            abi.encodeWithSelector(
                ZoneInterface.isValidOrder.selector,
                orderHash,
                msg.sender,
                offerer,
                zoneHash
            )
        );

        // Ensure call was successful and returned the correct magic value.
        _assertIsValidOrderStaticcallSuccess(success, orderHash);
    }

    /**
     * @dev Internal view function to determine whether an order is a restricted
     *      order and, if so, to ensure that it was either submitted by the
     *      offerer or the zone for the order, or that the zone returns the
     *      expected magic value upon performing a staticcall to `isValidOrder`
     *      or `isValidOrderIncludingExtraData` depending on whether the order
     *      fulfillment specifies extra data or criteria resolvers.
     *
     * @param advancedOrder     The advanced order in question.
     * @param criteriaResolvers An array where each element contains a reference
     *                          to a specific offer or consideration, a token
     *                          identifier, and a proof that the supplied token
     *                          identifier is contained in the order's merkle
     *                          root. Note that a criteria of zero indicates
     *                          that any (transferable) token identifier is
     *                          valid and that no proof needs to be supplied.
     * @param priorOrderHashes  The order hashes of each order supplied prior to
     *                          the current order as part of a "match" variety
     *                          of order fulfillment (e.g. this array will be
     *                          empty for single or "fulfill available").
     * @param orderHash         The hash of the order.
     * @param zoneHash          The hash to provide upon calling the zone.
     * @param orderType         The type of the order.
     * @param offerer           The offerer in question.
     * @param zone              The zone in question.
     */
    function _assertRestrictedAdvancedOrderValidity(
        AdvancedOrder memory advancedOrder,
        CriteriaResolver[] memory criteriaResolvers,
        bytes32[] memory priorOrderHashes,
        bytes32 orderHash,
        bytes32 zoneHash,
        OrderType orderType,
        address offerer,
        address zone
    ) internal view {
        // Order type 2-3 require zone or offerer be caller or zone to approve.
        if (
            uint256(orderType) > 1 &&
            msg.sender != zone &&
            msg.sender != offerer
        ) {
            // If no extraData or criteria resolvers are supplied...
            if (
                advancedOrder.extraData.length == 0 &&
                criteriaResolvers.length == 0
            ) {
                // Perform minimal staticcall to the zone.
                _callIsValidOrder(zone, orderHash, offerer, zoneHash);
            } else {
                // Otherwise, extra data or criteria resolvers were supplied; in
                // that event, perform a more verbose staticcall to the zone.
                bool success = _staticcall(
                    zone,
                    abi.encodeWithSelector(
                        ZoneInterface.isValidOrderIncludingExtraData.selector,
                        orderHash,
                        msg.sender,
                        advancedOrder,
                        priorOrderHashes,
                        criteriaResolvers
                    )
                );

                // Ensure call was successful and returned correct magic value.
                _assertIsValidOrderStaticcallSuccess(success, orderHash);
            }
        }
    }

    /**
     * @dev Internal view function to ensure that a staticcall to `isValidOrder`
     *      or `isValidOrderIncludingExtraData` as part of validating a
     *      restricted order that was not submitted by the named offerer or zone
     *      was successful and returned the required magic value.
     *
     * @param success   A boolean indicating the status of the staticcall.
     * @param orderHash The order hash of the order in question.
     */
    function _assertIsValidOrderStaticcallSuccess(
        bool success,
        bytes32 orderHash
    ) internal view {
        // If the call failed...
        if (!success) {
            // Revert and pass reason along if one was returned.
            _revertWithReasonIfOneIsReturned();

            // Otherwise, revert with a generic error message.
            revert InvalidRestrictedOrder(orderHash);
        }

        // Ensure result was extracted and matches isValidOrder magic value.
        if (_doesNotMatchMagic(ZoneInterface.isValidOrder.selector)) {
            revert InvalidRestrictedOrder(orderHash);
        }
    }
}

ZoneInteraction.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

/**
 * @title ZoneInteractionErrors
 * @author 0age
 * @notice ZoneInteractionErrors contains errors related to zone interaction.
 */
interface ZoneInteractionErrors {
    /**
     * @dev Revert with an error when attempting to fill an order that specifies
     *      a restricted submitter as its order type when not submitted by
     *      either the offerer or the order's zone or approved as valid by the
     *      zone in question via a staticcall to `isValidOrder`.
     *
     * @param orderHash The order hash for the invalid restricted order.
     */
    error InvalidRestrictedOrder(bytes32 orderHash);
}

ZoneInteractionErrors.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.7;

// prettier-ignore
import {
    AdvancedOrder,
    CriteriaResolver
} from "ConsiderationStructs.sol";

interface ZoneInterface {
    // Called by Consideration whenever extraData is not provided by the caller.
    function isValidOrder(
        bytes32 orderHash,
        address caller,
        address offerer,
        bytes32 zoneHash
    ) external view returns (bytes4 validOrderMagicValue);

    // Called by Consideration whenever any extraData is provided by the caller.
    function isValidOrderIncludingExtraData(
        bytes32 orderHash,
        address caller,
        AdvancedOrder calldata order,
        bytes32[] calldata priorOrderHashes,
        CriteriaResolver[] calldata criteriaResolvers
    ) external view returns (bytes4 validOrderMagicValue);
}