// File: contract-utils/Zerox/IExchange.sol

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity ^0.5.0;
pragma experimental ABIEncoderV2;

contract IExchange {
  function executeTransaction(
        uint256 salt,
        address signerAddress,
        bytes calldata data,
        bytes calldata signature
  ) external;
}

// File: contract-utils/Zerox/LibEIP712.sol

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/




contract LibEIP712 {

    // EIP191 header for EIP712 prefix
    string constant internal EIP191_HEADER = "\x19\x01";

    // EIP712 Domain Name value
    string constant internal EIP712_DOMAIN_NAME = "0x Protocol";

    // EIP712 Domain Version value
    string constant internal EIP712_DOMAIN_VERSION = "2";

    // Hash of the EIP712 Domain Separator Schema
    bytes32 constant internal EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH = keccak256(abi.encodePacked(
        "EIP712Domain(",
        "string name,",
        "string version,",
        "address verifyingContract",
        ")"
    ));

    // Hash of the EIP712 Domain Separator data
    // solhint-disable-next-line var-name-mixedcase
    bytes32 public EIP712_DOMAIN_HASH;

    constructor ()
        public
    {
        EIP712_DOMAIN_HASH = keccak256(abi.encodePacked(
            EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH,
            keccak256(bytes(EIP712_DOMAIN_NAME)),
            keccak256(bytes(EIP712_DOMAIN_VERSION)),
            bytes12(0),
            address(this)
        ));
    }

    /// @dev Calculates EIP712 encoding for a hash struct in this EIP712 Domain.
    /// @param hashStruct The EIP712 hash struct.
    /// @return EIP712 hash applied to this EIP712 Domain.
    function hashEIP712Message(bytes32 hashStruct)
        internal
        view
        returns (bytes32 result)
    {
        bytes32 eip712DomainHash = EIP712_DOMAIN_HASH;

        // Assembly for more efficient computing:
        // keccak256(abi.encodePacked(
        //     EIP191_HEADER,
        //     EIP712_DOMAIN_HASH,
        //     hashStruct    
        // ));

        assembly {
            // Load free memory pointer
            let memPtr := mload(64)

            mstore(memPtr, 0x1901000000000000000000000000000000000000000000000000000000000000)  // EIP191 header
            mstore(add(memPtr, 2), eip712DomainHash)                                            // EIP712 domain hash
            mstore(add(memPtr, 34), hashStruct)                                                 // Hash of struct

            // Compute hash
            result := keccak256(memPtr, 66)
        }
        return result;
    }
}

// File: contract-utils/Zerox/LibOrder.sol

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/





contract LibOrder is
    LibEIP712
{
    // Hash for the EIP712 Order Schema
    bytes32 constant internal EIP712_ORDER_SCHEMA_HASH = keccak256(abi.encodePacked(
        "Order(",
        "address makerAddress,",
        "address takerAddress,",
        "address feeRecipientAddress,",
        "address senderAddress,",
        "uint256 makerAssetAmount,",
        "uint256 takerAssetAmount,",
        "uint256 makerFee,",
        "uint256 takerFee,",
        "uint256 expirationTimeSeconds,",
        "uint256 salt,",
        "bytes makerAssetData,",
        "bytes takerAssetData",
        ")"
    ));

    // A valid order remains fillable until it is expired, fully filled, or cancelled.
    // An order's state is unaffected by external factors, like account balances.
    enum OrderStatus {
        INVALID,                     // Default value
        INVALID_MAKER_ASSET_AMOUNT,  // Order does not have a valid maker asset amount
        INVALID_TAKER_ASSET_AMOUNT,  // Order does not have a valid taker asset amount
        FILLABLE,                    // Order is fillable
        EXPIRED,                     // Order has already expired
        FULLY_FILLED,                // Order is fully filled
        CANCELLED                    // Order has been cancelled
    }

    // solhint-disable max-line-length
    struct Order {
        address makerAddress;           // Address that created the order.      
        address takerAddress;           // Address that is allowed to fill the order. If set to 0, any address is allowed to fill the order.          
        address feeRecipientAddress;    // Address that will recieve fees when order is filled.      
        address senderAddress;          // Address that is allowed to call Exchange contract methods that affect this order. If set to 0, any address is allowed to call these methods.
        uint256 makerAssetAmount;       // Amount of makerAsset being offered by maker. Must be greater than 0.        
        uint256 takerAssetAmount;       // Amount of takerAsset being bid on by maker. Must be greater than 0.        
        uint256 makerFee;               // Amount of ZRX paid to feeRecipient by maker when order is filled. If set to 0, no transfer of ZRX from maker to feeRecipient will be attempted.
        uint256 takerFee;               // Amount of ZRX paid to feeRecipient by taker when order is filled. If set to 0, no transfer of ZRX from taker to feeRecipient will be attempted.
        uint256 expirationTimeSeconds;  // Timestamp in seconds at which order expires.          
        uint256 salt;                   // Arbitrary number to facilitate uniqueness of the order's hash.     
        bytes makerAssetData;           // Encoded data that can be decoded by a specified proxy contract when transferring makerAsset. The last byte references the id of this proxy.
        bytes takerAssetData;           // Encoded data that can be decoded by a specified proxy contract when transferring takerAsset. The last byte references the id of this proxy.
    }
    // solhint-enable max-line-length

    struct OrderInfo {
        uint8 orderStatus;                    // Status that describes order's validity and fillability.
        bytes32 orderHash;                    // EIP712 hash of the order (see LibOrder.getOrderHash).
        uint256 orderTakerAssetFilledAmount;  // Amount of order that has already been filled.
    }

    /// @dev Calculates Keccak-256 hash of the order.
    /// @param order The order structure.
    /// @return Keccak-256 EIP712 hash of the order.
    function getOrderHash(Order memory order)
        internal
        view
        returns (bytes32 orderHash)
    {
        orderHash = hashEIP712Message(hashOrder(order));
        return orderHash;
    }

    /// @dev Calculates EIP712 hash of the order.
    /// @param order The order structure.
    /// @return EIP712 hash of the order.
    function hashOrder(Order memory order)
        internal
        pure
        returns (bytes32 result)
    {
        bytes32 schemaHash = EIP712_ORDER_SCHEMA_HASH;
        bytes32 makerAssetDataHash = keccak256(order.makerAssetData);
        bytes32 takerAssetDataHash = keccak256(order.takerAssetData);

        // Assembly for more efficiently computing:
        // keccak256(abi.encodePacked(
        //     EIP712_ORDER_SCHEMA_HASH,
        //     bytes32(order.makerAddress),
        //     bytes32(order.takerAddress),
        //     bytes32(order.feeRecipientAddress),
        //     bytes32(order.senderAddress),
        //     order.makerAssetAmount,
        //     order.takerAssetAmount,
        //     order.makerFee,
        //     order.takerFee,
        //     order.expirationTimeSeconds,
        //     order.salt,
        //     keccak256(order.makerAssetData),
        //     keccak256(order.takerAssetData)
        // ));

        assembly {
            // Calculate memory addresses that will be swapped out before hashing
            let pos1 := sub(order, 32)
            let pos2 := add(order, 320)
            let pos3 := add(order, 352)

            // Backup
            let temp1 := mload(pos1)
            let temp2 := mload(pos2)
            let temp3 := mload(pos3)
            
            // Hash in place
            mstore(pos1, schemaHash)
            mstore(pos2, makerAssetDataHash)
            mstore(pos3, takerAssetDataHash)
            result := keccak256(pos1, 416)
            
            // Restore
            mstore(pos1, temp1)
            mstore(pos2, temp2)
            mstore(pos3, temp3)
        }
        return result;
    }
}

// File: contract-utils/Zerox/LibBytes.sol

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/




library LibBytes {

    using LibBytes for bytes;

    /// @dev Gets the memory address for a byte array.
    /// @param input Byte array to lookup.
    /// @return memoryAddress Memory address of byte array. This
    ///         points to the header of the byte array which contains
    ///         the length.
    function rawAddress(bytes memory input)
        internal
        pure
        returns (uint256 memoryAddress)
    {
        assembly {
            memoryAddress := input
        }
        return memoryAddress;
    }
    
    /// @dev Gets the memory address for the contents of a byte array.
    /// @param input Byte array to lookup.
    /// @return memoryAddress Memory address of the contents of the byte array.
    function contentAddress(bytes memory input)
        internal
        pure
        returns (uint256 memoryAddress)
    {
        assembly {
            memoryAddress := add(input, 32)
        }
        return memoryAddress;
    }

    /// @dev Copies `length` bytes from memory location `source` to `dest`.
    /// @param dest memory address to copy bytes to.
    /// @param source memory address to copy bytes from.
    /// @param length number of bytes to copy.
    function memCopy(
        uint256 dest,
        uint256 source,
        uint256 length
    )
        internal
        pure
    {
        if (length < 32) {
            // Handle a partial word by reading destination and masking
            // off the bits we are interested in.
            // This correctly handles overlap, zero lengths and source == dest
            assembly {
                let mask := sub(exp(256, sub(32, length)), 1)
                let s := and(mload(source), not(mask))
                let d := and(mload(dest), mask)
                mstore(dest, or(s, d))
            }
        } else {
            // Skip the O(length) loop when source == dest.
            if (source == dest) {
                return;
            }

            // For large copies we copy whole words at a time. The final
            // word is aligned to the end of the range (instead of after the
            // previous) to handle partial words. So a copy will look like this:
            //
            //  ####
            //      ####
            //          ####
            //            ####
            //
            // We handle overlap in the source and destination range by
            // changing the copying direction. This prevents us from
            // overwriting parts of source that we still need to copy.
            //
            // This correctly handles source == dest
            //
            if (source > dest) {
                assembly {
                    // We subtract 32 from `sEnd` and `dEnd` because it
                    // is easier to compare with in the loop, and these
                    // are also the addresses we need for copying the
                    // last bytes.
                    length := sub(length, 32)
                    let sEnd := add(source, length)
                    let dEnd := add(dest, length)

                    // Remember the last 32 bytes of source
                    // This needs to be done here and not after the loop
                    // because we may have overwritten the last bytes in
                    // source already due to overlap.
                    let last := mload(sEnd)

                    // Copy whole words front to back
                    // Note: the first check is always true,
                    // this could have been a do-while loop.
                    // solhint-disable-next-line no-empty-blocks
                    for {} lt(source, sEnd) {} {
                        mstore(dest, mload(source))
                        source := add(source, 32)
                        dest := add(dest, 32)
                    }
                    
                    // Write the last 32 bytes
                    mstore(dEnd, last)
                }
            } else {
                assembly {
                    // We subtract 32 from `sEnd` and `dEnd` because those
                    // are the starting points when copying a word at the end.
                    length := sub(length, 32)
                    let sEnd := add(source, length)
                    let dEnd := add(dest, length)

                    // Remember the first 32 bytes of source
                    // This needs to be done here and not after the loop
                    // because we may have overwritten the first bytes in
                    // source already due to overlap.
                    let first := mload(source)

                    // Copy whole words back to front
                    // We use a signed comparisson here to allow dEnd to become
                    // negative (happens when source and dest < 32). Valid
                    // addresses in local memory will never be larger than
                    // 2**255, so they can be safely re-interpreted as signed.
                    // Note: the first check is always true,
                    // this could have been a do-while loop.
                    // solhint-disable-next-line no-empty-blocks
                    for {} slt(dest, dEnd) {} {
                        mstore(dEnd, mload(sEnd))
                        sEnd := sub(sEnd, 32)
                        dEnd := sub(dEnd, 32)
                    }
                    
                    // Write the first 32 bytes
                    mstore(dest, first)
                }
            }
        }
    }

    /// @dev Returns a slices from a byte array.
    /// @param b The byte array to take a slice from.
    /// @param from The starting index for the slice (inclusive).
    /// @param to The final index for the slice (exclusive).
    /// @return result The slice containing bytes at indices [from, to)
    function slice(
        bytes memory b,
        uint256 from,
        uint256 to
    )
        internal
        pure
        returns (bytes memory result)
    {
        require(
            from <= to,
            "FROM_LESS_THAN_TO_REQUIRED"
        );
        require(
            to < b.length,
            "TO_LESS_THAN_LENGTH_REQUIRED"
        );
        
        // Create a new bytes structure and copy contents
        result = new bytes(to - from);
        memCopy(
            result.contentAddress(),
            b.contentAddress() + from,
            result.length
        );
        return result;
    }
    
    /// @dev Returns a slice from a byte array without preserving the input.
    /// @param b The byte array to take a slice from. Will be destroyed in the process.
    /// @param from The starting index for the slice (inclusive).
    /// @param to The final index for the slice (exclusive).
    /// @return result The slice containing bytes at indices [from, to)
    /// @dev When `from == 0`, the original array will match the slice. In other cases its state will be corrupted.
    function sliceDestructive(
        bytes memory b,
        uint256 from,
        uint256 to
    )
        internal
        pure
        returns (bytes memory result)
    {
        require(
            from <= to,
            "FROM_LESS_THAN_TO_REQUIRED"
        );
        require(
            to < b.length,
            "TO_LESS_THAN_LENGTH_REQUIRED"
        );
        
        // Create a new bytes structure around [from, to) in-place.
        assembly {
            result := add(b, from)
            mstore(result, sub(to, from))
        }
        return result;
    }

    /// @dev Pops the last byte off of a byte array by modifying its length.
    /// @param b Byte array that will be modified.
    /// @return The byte that was popped off.
    function popLastByte(bytes memory b)
        internal
        pure
        returns (bytes1 result)
    {
        require(
            b.length > 0,
            "GREATER_THAN_ZERO_LENGTH_REQUIRED"
        );

        // Store last byte.
        result = b[b.length - 1];

        assembly {
            // Decrement length of byte array.
            let newLen := sub(mload(b), 1)
            mstore(b, newLen)
        }
        return result;
    }

    /// @dev Pops the last 20 bytes off of a byte array by modifying its length.
    /// @param b Byte array that will be modified.
    /// @return The 20 byte address that was popped off.
    function popLast20Bytes(bytes memory b)
        internal
        pure
        returns (address result)
    {
        require(
            b.length >= 20,
            "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED"
        );

        // Store last 20 bytes.
        result = readAddress(b, b.length - 20);

        assembly {
            // Subtract 20 from byte array length.
            let newLen := sub(mload(b), 20)
            mstore(b, newLen)
        }
        return result;
    }

    /// @dev Tests equality of two byte arrays.
    /// @param lhs First byte array to compare.
    /// @param rhs Second byte array to compare.
    /// @return True if arrays are the same. False otherwise.
    function equals(
        bytes memory lhs,
        bytes memory rhs
    )
        internal
        pure
        returns (bool equal)
    {
        // Keccak gas cost is 30 + numWords * 6. This is a cheap way to compare.
        // We early exit on unequal lengths, but keccak would also correctly
        // handle this.
        return lhs.length == rhs.length && keccak256(lhs) == keccak256(rhs);
    }

    /// @dev Reads an address from a position in a byte array.
    /// @param b Byte array containing an address.
    /// @param index Index in byte array of address.
    /// @return address from byte array.
    function readAddress(
        bytes memory b,
        uint256 index
    )
        internal
        pure
        returns (address result)
    {
        require(
            b.length >= index + 20,  // 20 is length of address
            "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED"
        );

        // Add offset to index:
        // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
        // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)
        index += 20;

        // Read address from array memory
        assembly {
            // 1. Add index to address of bytes array
            // 2. Load 32-byte word from memory
            // 3. Apply 20-byte mask to obtain address
            result := and(mload(add(b, index)), 0xffffffffffffffffffffffffffffffffffffffff)
        }
        return result;
    }

    /// @dev Writes an address into a specific position in a byte array.
    /// @param b Byte array to insert address into.
    /// @param index Index in byte array of address.
    /// @param input Address to put into byte array.
    function writeAddress(
        bytes memory b,
        uint256 index,
        address input
    )
        internal
        pure
    {
        require(
            b.length >= index + 20,  // 20 is length of address
            "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED"
        );

        // Add offset to index:
        // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
        // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)
        index += 20;

        // Store address into array memory
        assembly {
            // The address occupies 20 bytes and mstore stores 32 bytes.
            // First fetch the 32-byte word where we'll be storing the address, then
            // apply a mask so we have only the bytes in the word that the address will not occupy.
            // Then combine these bytes with the address and store the 32 bytes back to memory with mstore.

            // 1. Add index to address of bytes array
            // 2. Load 32-byte word from memory
            // 3. Apply 12-byte mask to obtain extra bytes occupying word of memory where we'll store the address
            let neighbors := and(
                mload(add(b, index)),
                0xffffffffffffffffffffffff0000000000000000000000000000000000000000
            )
            
            // Make sure input address is clean.
            // (Solidity does not guarantee this)
            input := and(input, 0xffffffffffffffffffffffffffffffffffffffff)

            // Store the neighbors and address into memory
            mstore(add(b, index), xor(input, neighbors))
        }
    }

    /// @dev Reads a bytes32 value from a position in a byte array.
    /// @param b Byte array containing a bytes32 value.
    /// @param index Index in byte array of bytes32 value.
    /// @return bytes32 value from byte array.
    function readBytes32(
        bytes memory b,
        uint256 index
    )
        internal
        pure
        returns (bytes32 result)
    {
        require(
            b.length >= index + 32,
            "GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED"
        );

        // Arrays are prefixed by a 256 bit length parameter
        index += 32;

        // Read the bytes32 from array memory
        assembly {
            result := mload(add(b, index))
        }
        return result;
    }

    /// @dev Writes a bytes32 into a specific position in a byte array.
    /// @param b Byte array to insert <input> into.
    /// @param index Index in byte array of <input>.
    /// @param input bytes32 to put into byte array.
    function writeBytes32(
        bytes memory b,
        uint256 index,
        bytes32 input
    )
        internal
        pure
    {
        require(
            b.length >= index + 32,
            "GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED"
        );

        // Arrays are prefixed by a 256 bit length parameter
        index += 32;

        // Read the bytes32 from array memory
        assembly {
            mstore(add(b, index), input)
        }
    }

    /// @dev Reads a uint256 value from a position in a byte array.
    /// @param b Byte array containing a uint256 value.
    /// @param index Index in byte array of uint256 value.
    /// @return uint256 value from byte array.
    function readUint256(
        bytes memory b,
        uint256 index
    )
        internal
        pure
        returns (uint256 result)
    {
        result = uint256(readBytes32(b, index));
        return result;
    }

    /// @dev Writes a uint256 into a specific position in a byte array.
    /// @param b Byte array to insert <input> into.
    /// @param index Index in byte array of <input>.
    /// @param input uint256 to put into byte array.
    function writeUint256(
        bytes memory b,
        uint256 index,
        uint256 input
    )
        internal
        pure
    {
        writeBytes32(b, index, bytes32(input));
    }

    /// @dev Reads an unpadded bytes4 value from a position in a byte array.
    /// @param b Byte array containing a bytes4 value.
    /// @param index Index in byte array of bytes4 value.
    /// @return bytes4 value from byte array.
    function readBytes4(
        bytes memory b,
        uint256 index
    )
        internal
        pure
        returns (bytes4 result)
    {
        require(
            b.length >= index + 4,
            "GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED"
        );

        // Arrays are prefixed by a 32 byte length field
        index += 32;

        // Read the bytes4 from array memory
        assembly {
            result := mload(add(b, index))
            // Solidity does not require us to clean the trailing bytes.
            // We do it anyway
            result := and(result, 0xFFFFFFFF00000000000000000000000000000000000000000000000000000000)
        }
        return result;
    }

    function readBytes2(
        bytes memory b,
        uint256 index
    )
        internal
        pure
        returns (bytes2 result)
    {
        require(
            b.length >= index + 2,
            "GREATER_OR_EQUAL_TO_2_LENGTH_REQUIRED"
        );

        // Arrays are prefixed by a 32 byte length field
        index += 32;

        // Read the bytes4 from array memory
        assembly {
            result := mload(add(b, index))
            // Solidity does not require us to clean the trailing bytes.
            // We do it anyway
            result := and(result, 0xFFFF000000000000000000000000000000000000000000000000000000000000)
        }
        return result;
    }

    /// @dev Reads nested bytes from a specific position.
    /// @dev NOTE: the returned value overlaps with the input value.
    ///            Both should be treated as immutable.
    /// @param b Byte array containing nested bytes.
    /// @param index Index of nested bytes.
    /// @return result Nested bytes.
    function readBytesWithLength(
        bytes memory b,
        uint256 index
    )
        internal
        pure
        returns (bytes memory result)
    {
        // Read length of nested bytes
        uint256 nestedBytesLength = readUint256(b, index);
        index += 32;

        // Assert length of <b> is valid, given
        // length of nested bytes
        require(
            b.length >= index + nestedBytesLength,
            "GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED"
        );
        
        // Return a pointer to the byte array as it exists inside `b`
        assembly {
            result := add(b, index)
        }
        return result;
    }

    /// @dev Inserts bytes at a specific position in a byte array.
    /// @param b Byte array to insert <input> into.
    /// @param index Index in byte array of <input>.
    /// @param input bytes to insert.
    function writeBytesWithLength(
        bytes memory b,
        uint256 index,
        bytes memory input
    )
        internal
        pure
    {
        // Assert length of <b> is valid, given
        // length of input
        require(
            b.length >= index + 32 + input.length,  // 32 bytes to store length
            "GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED"
        );

        // Copy <input> into <b>
        memCopy(
            b.contentAddress() + index,
            input.rawAddress(), // includes length of <input>
            input.length + 32   // +32 bytes to store <input> length
        );
    }

    /// @dev Performs a deep copy of a byte array onto another byte array of greater than or equal length.
    /// @param dest Byte array that will be overwritten with source bytes.
    /// @param source Byte array to copy onto dest bytes.
    function deepCopyBytes(
        bytes memory dest,
        bytes memory source
    )
        internal
        pure
    {
        uint256 sourceLen = source.length;
        // Dest length must be >= source length, or some bytes would not be copied.
        require(
            dest.length >= sourceLen,
            "GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED"
        );
        memCopy(
            dest.contentAddress(),
            source.contentAddress(),
            sourceLen
        );
    }
}

// File: contract-utils/Zerox/LibDecoder.sol




contract LibDecoder {
    using LibBytes for bytes;

    function decodeFillOrder(bytes memory data) internal pure returns(LibOrder.Order memory order, uint256 takerFillAmount, bytes memory mmSignature) {
        require(
            data.length > 800,
            "LENGTH_LESS_800"
        );

        // compare method_id
        // 0x64a3bc15 is fillOrKillOrder's method id.
        require(
            data.readBytes4(0) == 0x64a3bc15,
            "WRONG_METHOD_ID"
        );
        
        bytes memory dataSlice;
        assembly {
            dataSlice := add(data, 4)
        }
        //return (order, takerFillAmount, data);
        return abi.decode(dataSlice, (LibOrder.Order, uint256, bytes));

    }

    function decodeMmSignatureWithoutSign(bytes memory signature) internal pure returns(address user, uint16 feeFactor) {
        require(
            signature.length == 87 || signature.length == 88,
            "LENGTH_87_REQUIRED"
        );

        user = signature.readAddress(65);
        feeFactor = uint16(signature.readBytes2(85));
        
        require(
            feeFactor < 10000,
            "FEE_FACTOR_MORE_THEN_10000"
        );

        return (user, feeFactor);
    }

    function decodeMmSignature(bytes memory signature) internal pure returns(uint8 v, bytes32 r, bytes32 s, address user, uint16 feeFactor) {
        (user, feeFactor) = decodeMmSignatureWithoutSign(signature);

        v = uint8(signature[0]);
        r = signature.readBytes32(1);
        s = signature.readBytes32(33);

        return (v, r, s, user, feeFactor);
    }

    function decodeUserSignatureWithoutSign(bytes memory signature) internal pure returns(address receiver) {
        require(
            signature.length == 85 || signature.length == 86,
            "LENGTH_85_REQUIRED"
        );
        receiver = signature.readAddress(65);

        return receiver;
    }

    function decodeUserSignature(bytes memory signature) internal pure returns(uint8 v, bytes32 r, bytes32 s, address receiver) {
        receiver = decodeUserSignatureWithoutSign(signature);

        v = uint8(signature[0]);
        r = signature.readBytes32(1);
        s = signature.readBytes32(33);

        return (v, r, s, receiver);
    }

    function decodeERC20Asset(bytes memory assetData) internal pure returns(address) {
        require(
            assetData.length == 36,
            "LENGTH_65_REQUIRED"
        );

        return assetData.readAddress(16);
    }
}

// File: contract-utils/Zerox/LibEncoder.sol




contract LibEncoder is
    LibEIP712
{
    // Hash for the EIP712 ZeroEx Transaction Schema
    bytes32 constant internal EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH = keccak256(
        abi.encodePacked(
        "ZeroExTransaction(",
        "uint256 salt,",
        "address signerAddress,",
        "bytes data",
        ")"
    ));

    function encodeTransactionHash(
        uint256 salt,
        address signerAddress,
        bytes memory data
    )
        internal
        view 
        returns (bytes32 result)
    {
        bytes32 schemaHash = EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH;
        bytes32 dataHash = keccak256(data);

        // Assembly for more efficiently computing:
        // keccak256(abi.encodePacked(
        //     EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH,
        //     salt,
        //     bytes32(signerAddress),
        //     keccak256(data)
        // ));

        assembly {
            // Load free memory pointer
            let memPtr := mload(64)

            mstore(memPtr, schemaHash)                                                               // hash of schema
            mstore(add(memPtr, 32), salt)                                                            // salt
            mstore(add(memPtr, 64), and(signerAddress, 0xffffffffffffffffffffffffffffffffffffffff))  // signerAddress
            mstore(add(memPtr, 96), dataHash)                                                        // hash of data

            // Compute hash
            result := keccak256(memPtr, 128)
        }
        result = hashEIP712Message(result);
        return result;
    }
}

// File: contract-utils/Ownable/IOwnable.sol



contract IOwnable {
  function transferOwnership(address newOwner) public;

  function setOperator(address newOwner) public;
}

// File: contract-utils/Ownable/Ownable.sol





contract Ownable is
  IOwnable
{
  address public owner;
  address public operator;

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

  modifier onlyOwner() {
    require(
      msg.sender == owner,
      "ONLY_CONTRACT_OWNER"
    );
    _;
  }

  modifier onlyOperator() {
    require(
      msg.sender == operator,
      "ONLY_CONTRACT_OPERATOR"
    );
    _;
  }

  function transferOwnership(address newOwner)
    public
    onlyOwner
  {
    if (newOwner != address(0)) {
      owner = newOwner;
    }
  }

  function setOperator(address newOperator)
    public
    onlyOwner 
  {
    operator = newOperator;
  }
}

// File: contract-utils/Interface/IUserProxy.sol



contract IUserProxy {
    function receiveToken(address tokenAddr, address userAddr, uint256 amount) external;

    function sendToken(address tokenAddr, address userAddr, uint256 amount) external;

    function receiveETH(address wethAddr) payable external;

    function sendETH(address wethAddr, address payable userAddr, uint256 amount) external;
}

// File: openzeppelin-solidity/contracts/math/SafeMath.sol



/**
 * @title SafeMath
 * @dev Unsigned math operations with safety checks that revert on error
 */
library SafeMath {
    /**
    * @dev Multiplies two unsigned integers, reverts on overflow.
    */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b);

        return c;
    }

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

        return c;
    }

    /**
    * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
    */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

    /**
    * @dev Adds two unsigned integers, reverts on overflow.
    */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    /**
    * @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
    * reverts when dividing by zero.
    */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }
}

// File: contracts/TokenlonExchange.sol



contract TokenlonExchange is 
    Ownable,
    LibDecoder,
    LibEncoder
{
    string public version = "0.0.3";

    IExchange internal ZX_EXCHANGE;
    IUserProxy internal USER_PROXY; 
    address internal WETH_ADDR;

    // exchange is enabled
    bool public isEnabled = false;

    // marketMakerProxy white list:
    mapping(address=>bool) public isMarketMakerProxy;

    // executeTxHash => user
    mapping(bytes32=>address) public transactions;

    constructor () public {
        owner = msg.sender;
        operator = msg.sender;
    }

    // events
    event FillOrder(
        bytes32 indexed executeTxHash,
        address indexed userAddr,
        address receiverAddr,
        uint256 filledAmount, 
        uint256 acutalMakerAssetAmount
    );

    // fillOrder with token
    // sender is any external accounts
    // 0x order successed send eth to user
    function fillOrderWithToken(
        uint256 userSalt,
        bytes memory data,
        bytes memory userSignature
    )
        public
    {
        require(isEnabled, "EXCHANGE_DISABLED");

        // decode & assert
        (LibOrder.Order memory order,
        address user,
        address receiver,
        uint16 feeFactor,
        address makerAssetAddr,
        address takerAssetAddr,
        bytes32 transactionHash) = assertTransaction(userSalt, data, userSignature);

        // saved transaction
        transactions[transactionHash] = user;

        // USER_PROXY transfer user's token
        USER_PROXY.receiveToken(takerAssetAddr, user, order.takerAssetAmount);

        // send tx to 0x
        ZX_EXCHANGE.executeTransaction(
            userSalt,
            address(USER_PROXY),
            data,
            userSignature
        );

        // settle token/ETH to user
        uint256 acutalMakerAssetAmount = settle(receiver, makerAssetAddr, order.makerAssetAmount, feeFactor);

        emit FillOrder(transactionHash, user, receiver, order.takerAssetAmount, acutalMakerAssetAmount);
    }

    function fillOrderWithETH(
        uint256 userSalt,
        bytes memory data,
        bytes memory userSignature
    )
        public
        payable
    {
        require(isEnabled, "EXCHANGE_DISABLED");

        // decode & assert
        (LibOrder.Order memory order,
        address user,
        address receiver,
        uint16 feeFactor,
        address makerAssetAddr,
        address takerAssetAddr,
        bytes32 transactionHash) = assertTransaction(userSalt, data, userSignature);

        require(
            msg.sender == user,
            "SENDER_IS_NOT_USER"
        );

        require(
            WETH_ADDR == takerAssetAddr,
            "USER_ASSET_NOT_WETH"
        );

        require(
            msg.value == order.takerAssetAmount,
            "ETH_NOT_ENOUGH"
        );

        // saved transaction
        transactions[transactionHash] = user;

        // USER_PROXY receive eth from TokenlonExchange
        USER_PROXY.receiveETH.value(msg.value)(WETH_ADDR);

        // send tx to 0x
        ZX_EXCHANGE.executeTransaction(
            userSalt,
            address(USER_PROXY),
            data,
            userSignature
        );

        // settle token/ETH to user
        uint256 acutalMakerAssetAmount = settle(receiver, makerAssetAddr, order.makerAssetAmount, feeFactor);

        emit FillOrder(transactionHash, user, receiver, order.takerAssetAmount, acutalMakerAssetAmount);
    }

    // assert & decode transaction
    function assertTransaction(uint256 userSalt, bytes memory data, bytes memory userSignature)
    public view returns(
        LibOrder.Order memory order,
        address user,
        address receiver,
        uint16 feeFactor,
        address makerAssetAddr,
        address takerAssetAddr,
        bytes32 transactionHash
    ){
        // decode fillOrder data
        uint256 takerFillAmount;
        bytes memory mmSignature;
        (order, takerFillAmount, mmSignature) = decodeFillOrder(data);

        require(
            this.isMarketMakerProxy(order.makerAddress),
            "MAKER_ADDRESS_ERROR"
        );

        require(
            order.takerAddress == address(USER_PROXY),
            "TAKER_ADDRESS_ERROR"
        );
        require(
            order.takerAssetAmount == takerFillAmount,
            "FIll_AMOUNT_ERROR"
        );

        // generate transactionHash
        transactionHash = encodeTransactionHash(
            userSalt,
            address(USER_PROXY),
            data
        );

        require(
            transactions[transactionHash] == address(0),
            "EXECUTED_TX_HASH"
        );

        // decode mmSignature
        (user, feeFactor) = decodeMmSignatureWithoutSign(mmSignature);

        require(
            feeFactor < 10000,
            "FEE_FACTOR_MORE_THEN_10000"
        );

        // decode userSignature
        receiver = decodeUserSignatureWithoutSign(userSignature);

        require(
            receiver != address(0),
            "INVALID_RECIVER"
        );

        // decode asset
        // just support ERC20
        makerAssetAddr = decodeERC20Asset(order.makerAssetData);
        takerAssetAddr = decodeERC20Asset(order.takerAssetData);

        return (
            order,
            user,
            receiver,
            feeFactor,
            makerAssetAddr,
            takerAssetAddr,
            transactionHash
        );        
    }

    // settle
    function settle(address receiver, address makerAssetAddr, uint256 makerAssetAmount, uint16 feeFactor) internal returns(uint256) {
        uint256 settleAmount = deductFee(makerAssetAmount, feeFactor);

        if (makerAssetAddr == WETH_ADDR){
            USER_PROXY.sendETH(WETH_ADDR, address(uint160(receiver)), settleAmount);
        } else {
            USER_PROXY.sendToken(makerAssetAddr, receiver, settleAmount);
        }

        return settleAmount;
    }

    // deduct fee
    function deductFee(uint256 makerAssetAmount, uint16 feeFactor) internal pure returns (uint256) {
        if(feeFactor == 0) {
            return makerAssetAmount;
        }

        uint256 fee = SafeMath.div(SafeMath.mul(makerAssetAmount, feeFactor), 10000);
        return SafeMath.sub(makerAssetAmount, fee);
    }

    // manage 
    function registerMMP(address _marketMakerProxy, bool _add) public onlyOperator {
        isMarketMakerProxy[_marketMakerProxy] = _add;
    }

    function setProxy(IExchange _exchange, IUserProxy _userProxy, address _weth) public onlyOperator {
        ZX_EXCHANGE = _exchange;
        USER_PROXY = _userProxy;
        WETH_ADDR = _weth;

        // this const follow ZX_EXCHANGE address
        // encodeTransactionHash depend ZX_EXCHANGE address
        EIP712_DOMAIN_HASH = keccak256(
            abi.encodePacked(
                EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH,
                keccak256(bytes(EIP712_DOMAIN_NAME)),
                keccak256(bytes(EIP712_DOMAIN_VERSION)),
                bytes12(0),
                address(ZX_EXCHANGE)
            )
        );
    }

    function setEnabled(bool _enable) public onlyOperator {
        isEnabled = _enable;
    }

}

pragma solidity ^0.4.24;

// File: contracts/zeppelin/Proxy.sol

/**
 * @title Proxy
 * @dev Implements delegation of calls to other contracts, with proper
 * forwarding of return values and bubbling of failures.
 * It defines a fallback function that delegates all calls to the address
 * returned by the abstract _implementation() internal function.
 */
contract Proxy {
    /**
     * @dev Fallback function.
     * Implemented entirely in `_fallback`.
     */
    function () payable external {
        _fallback();
    }

    /**
     * @return The Address of the implementation.
     */
    function _implementation() internal view returns (address);

    /**
     * @dev Delegates execution to an implementation contract.
     * This is a low level function that doesn't return to its internal call site.
     * It will return to the external caller whatever the implementation returns.
     * @param implementation Address to delegate.
     */
    function _delegate(address implementation) internal {
        assembly {
        // Copy msg.data. We take full control of memory in this inline assembly
        // block because it will not return to Solidity code. We overwrite the
        // Solidity scratch pad at memory position 0.
            calldatacopy(0, 0, calldatasize)

        // Call the implementation.
        // out and outsize are 0 because we don't know the size yet.
            let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)

        // Copy the returned data.
            returndatacopy(0, 0, returndatasize)

            switch result
            // delegatecall returns 0 on error.
            case 0 { revert(0, returndatasize) }
            default { return(0, returndatasize) }
        }
    }

    /**
     * @dev Function that is run as the first thing in the fallback function.
     * Can be redefined in derived contracts to add functionality.
     * Redefinitions must call super._willFallback().
     */
    function _willFallback() internal {
    }

    /**
     * @dev fallback implementation.
     * Extracted to enable manual triggering.
     */
    function _fallback() internal {
        _willFallback();
        _delegate(_implementation());
    }
}

// File: contracts/zeppelin/AddressUtils.sol

/**
 * Utility library of inline functions on addresses
 */
library AddressUtils {

    /**
     * Returns whether the target address is a contract
     * @dev This function will return false if invoked during the constructor of a contract,
     * as the code is not actually created until after the constructor finishes.
     * @param addr address to check
     * @return whether the target address is a contract
     */
    function isContract(address addr) internal view returns (bool) {
        uint256 size;
        // XXX Currently there is no better way to check if there is a contract in an address
        // than to check the size of the code at that address.
        // See https://ethereum.stackexchange.com/a/14016/36603
        // for more details about how this works.
        // TODO Check this again before the Serenity release, because all addresses will be
        // contracts then.
        // solium-disable-next-line security/no-inline-assembly
        assembly { size := extcodesize(addr) }
        return size > 0;
    }

}

// File: contracts/zeppelin/UpgradeabilityProxy.sol

/**
 * @title UpgradeabilityProxy
 * @dev This contract implements a proxy that allows to change the
 * implementation address to which it will delegate.
 * Such a change is called an implementation upgrade.
 */
contract UpgradeabilityProxy is Proxy {
    /**
     * @dev Emitted when the implementation is upgraded.
     * @param implementation Address of the new implementation.
     */
    event Upgraded(address implementation);

    /**
     * @dev Storage slot with the address of the current implementation.
     * This is the keccak-256 hash of "org.zeppelinos.proxy.implementation", and is
     * validated in the constructor.
     */
    bytes32 private constant IMPLEMENTATION_SLOT = 0x7050c9e0f4ca769c69bd3a8ef740bc37934f8e2c036e5a723fd8ee048ed3f8c3;

    /**
     * @dev Contract constructor.
     * @param _implementation Address of the initial implementation.
     */
    constructor(address _implementation) public {
        assert(IMPLEMENTATION_SLOT == keccak256("org.zeppelinos.proxy.implementation"));

        _setImplementation(_implementation);
    }

    /**
     * @dev Returns the current implementation.
     * @return Address of the current implementation
     */
    function _implementation() internal view returns (address impl) {
        bytes32 slot = IMPLEMENTATION_SLOT;
        assembly {
            impl := sload(slot)
        }
    }

    /**
     * @dev Upgrades the proxy to a new implementation.
     * @param newImplementation Address of the new implementation.
     */
    function _upgradeTo(address newImplementation) internal {
        _setImplementation(newImplementation);
        emit Upgraded(newImplementation);
    }

    /**
     * @dev Sets the implementation address of the proxy.
     * @param newImplementation Address of the new implementation.
     */
    function _setImplementation(address newImplementation) private {
        require(AddressUtils.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");

        bytes32 slot = IMPLEMENTATION_SLOT;

        assembly {
            sstore(slot, newImplementation)
        }
    }
}

// File: contracts/zeppelin/AdminUpgradeabilityProxy.sol

/**
 * @title AdminUpgradeabilityProxy
 * @dev This contract combines an upgradeability proxy with an authorization
 * mechanism for administrative tasks.
 * All external functions in this contract must be guarded by the
 * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
 * feature proposal that would enable this to be done automatically.
 */
contract AdminUpgradeabilityProxy is UpgradeabilityProxy {
    /**
     * @dev Emitted when the administration has been transferred.
     * @param previousAdmin Address of the previous admin.
     * @param newAdmin Address of the new admin.
     */
    event AdminChanged(address previousAdmin, address newAdmin);

    /**
     * @dev Storage slot with the admin of the contract.
     * This is the keccak-256 hash of "org.zeppelinos.proxy.admin", and is
     * validated in the constructor.
     */
    bytes32 private constant ADMIN_SLOT = 0x10d6a54a4754c8869d6886b5f5d7fbfa5b4522237ea5c60d11bc4e7a1ff9390b;

    /**
     * @dev Modifier to check whether the `msg.sender` is the admin.
     * If it is, it will run the function. Otherwise, it will delegate the call
     * to the implementation.
     */
    modifier ifAdmin() {
        if (msg.sender == _admin()) {
            _;
        } else {
            _fallback();
        }
    }

    /**
     * Contract constructor.
     * It sets the `msg.sender` as the proxy administrator.
     * @param _implementation address of the initial implementation.
     */
    constructor(address _implementation) UpgradeabilityProxy(_implementation) public {
        assert(ADMIN_SLOT == keccak256("org.zeppelinos.proxy.admin"));

        _setAdmin(msg.sender);
    }

    /**
     * @return The address of the proxy admin.
     */
    function admin() external view ifAdmin returns (address) {
        return _admin();
    }

    /**
     * @return The address of the implementation.
     */
    function implementation() external view ifAdmin returns (address) {
        return _implementation();
    }

    /**
     * @dev Changes the admin of the proxy.
     * Only the current admin can call this function.
     * @param newAdmin Address to transfer proxy administration to.
     */
    function changeAdmin(address newAdmin) external ifAdmin {
        require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
        emit AdminChanged(_admin(), newAdmin);
        _setAdmin(newAdmin);
    }

    /**
     * @dev Upgrade the backing implementation of the proxy.
     * Only the admin can call this function.
     * @param newImplementation Address of the new implementation.
     */
    function upgradeTo(address newImplementation) external ifAdmin {
        _upgradeTo(newImplementation);
    }

    /**
     * @dev Upgrade the backing implementation of the proxy and call a function
     * on the new implementation.
     * This is useful to initialize the proxied contract.
     * @param newImplementation Address of the new implementation.
     * @param data Data to send as msg.data in the low level call.
     * It should include the signature and the parameters of the function to be
     * called, as described in
     * https://solidity.readthedocs.io/en/develop/abi-spec.html#function-selector-and-argument-encoding.
     */
    function upgradeToAndCall(address newImplementation, bytes data) payable external ifAdmin {
        _upgradeTo(newImplementation);
        require(address(this).call.value(msg.value)(data));
    }

    /**
     * @return The admin slot.
     */
    function _admin() internal view returns (address adm) {
        bytes32 slot = ADMIN_SLOT;
        assembly {
            adm := sload(slot)
        }
    }

    /**
     * @dev Sets the address of the proxy admin.
     * @param newAdmin Address of the new proxy admin.
     */
    function _setAdmin(address newAdmin) internal {
        bytes32 slot = ADMIN_SLOT;

        assembly {
            sstore(slot, newAdmin)
        }
    }

    /**
     * @dev Only fall back when the sender is not the admin.
     */
    function _willFallback() internal {
        require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
        super._willFallback();
    }
}

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;
pragma experimental ABIEncoderV2;

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;


// solhint-disable max-line-length
contract LibConstants {
   
    // Asset data for ZRX token. Used for fee transfers.
    // @TODO: Hardcode constant when we deploy. Currently 
    //        not constant to make testing easier.

    // The proxyId for ZRX_ASSET_DATA is bytes4(keccak256("ERC20Token(address)")) = 0xf47261b0
    
    // Kovan ZRX address is 0x6ff6c0ff1d68b964901f986d4c9fa3ac68346570.
    // The ABI encoded proxyId and address is 0xf47261b00000000000000000000000006ff6c0ff1d68b964901f986d4c9fa3ac68346570
    // bytes constant public ZRX_ASSET_DATA = "\xf4\x72\x61\xb0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x6f\xf6\xc0\xff\x1d\x68\xb9\x64\x90\x1f\x98\x6d\x4c\x9f\xa3\xac\x68\x34\x65\x70";
    
    // Mainnet ZRX address is 0xe41d2489571d322189246dafa5ebde1f4699f498.
    // The ABI encoded proxyId and address is 0xf47261b0000000000000000000000000e41d2489571d322189246dafa5ebde1f4699f498
    // bytes constant public ZRX_ASSET_DATA = "\xf4\x72\x61\xb0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xe4\x1d\x24\x89\x57\x1d\x32\x21\x89\x24\x6d\xaf\xa5\xeb\xde\x1f\x46\x99\xf4\x98";
    
    // solhint-disable-next-line var-name-mixedcase
    bytes public ZRX_ASSET_DATA;

    // @TODO: Remove when we deploy.
    constructor (bytes memory zrxAssetData)
        public
    {
        ZRX_ASSET_DATA = zrxAssetData;
    }
}
// solhint-enable max-line-length

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;


contract ReentrancyGuard {

    // Locked state of mutex
    bool private locked = false;

    /// @dev Functions with this modifer cannot be reentered. The mutex will be locked
    ///      before function execution and unlocked after.
    modifier nonReentrant() {
        // Ensure mutex is unlocked
        require(
            !locked,
            "REENTRANCY_ILLEGAL"
        );

        // Lock mutex before function call
        locked = true;

        // Perform function call
        _;

        // Unlock mutex after function call
        locked = false;
    }
}


/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;

pragma solidity 0.4.24;


contract SafeMath {

    function safeMul(uint256 a, uint256 b)
        internal
        pure
        returns (uint256)
    {
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        require(
            c / a == b,
            "UINT256_OVERFLOW"
        );
        return c;
    }

    function safeDiv(uint256 a, uint256 b)
        internal
        pure
        returns (uint256)
    {
        uint256 c = a / b;
        return c;
    }

    function safeSub(uint256 a, uint256 b)
        internal
        pure
        returns (uint256)
    {
        require(
            b <= a,
            "UINT256_UNDERFLOW"
        );
        return a - b;
    }

    function safeAdd(uint256 a, uint256 b)
        internal
        pure
        returns (uint256)
    {
        uint256 c = a + b;
        require(
            c >= a,
            "UINT256_OVERFLOW"
        );
        return c;
    }

    function max64(uint64 a, uint64 b)
        internal
        pure
        returns (uint256)
    {
        return a >= b ? a : b;
    }

    function min64(uint64 a, uint64 b)
        internal
        pure
        returns (uint256)
    {
        return a < b ? a : b;
    }

    function max256(uint256 a, uint256 b)
        internal
        pure
        returns (uint256)
    {
        return a >= b ? a : b;
    }

    function min256(uint256 a, uint256 b)
        internal
        pure
        returns (uint256)
    {
        return a < b ? a : b;
    }
}



contract LibFillResults is
    SafeMath
{
    struct FillResults {
        uint256 makerAssetFilledAmount;  // Total amount of makerAsset(s) filled.
        uint256 takerAssetFilledAmount;  // Total amount of takerAsset(s) filled.
        uint256 makerFeePaid;            // Total amount of ZRX paid by maker(s) to feeRecipient(s).
        uint256 takerFeePaid;            // Total amount of ZRX paid by taker to feeRecipients(s).
    }

    struct MatchedFillResults {
        FillResults left;                    // Amounts filled and fees paid of left order.
        FillResults right;                   // Amounts filled and fees paid of right order.
        uint256 leftMakerAssetSpreadAmount;  // Spread between price of left and right order, denominated in the left order's makerAsset, paid to taker.
    }

    /// @dev Adds properties of both FillResults instances.
    ///      Modifies the first FillResults instance specified.
    /// @param totalFillResults Fill results instance that will be added onto.
    /// @param singleFillResults Fill results instance that will be added to totalFillResults.
    function addFillResults(FillResults memory totalFillResults, FillResults memory singleFillResults)
        internal
        pure
    {
        totalFillResults.makerAssetFilledAmount = safeAdd(totalFillResults.makerAssetFilledAmount, singleFillResults.makerAssetFilledAmount);
        totalFillResults.takerAssetFilledAmount = safeAdd(totalFillResults.takerAssetFilledAmount, singleFillResults.takerAssetFilledAmount);
        totalFillResults.makerFeePaid = safeAdd(totalFillResults.makerFeePaid, singleFillResults.makerFeePaid);
        totalFillResults.takerFeePaid = safeAdd(totalFillResults.takerFeePaid, singleFillResults.takerFeePaid);
    }
}

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;


contract LibEIP712 {

    // EIP191 header for EIP712 prefix
    string constant internal EIP191_HEADER = "\x19\x01";

    // EIP712 Domain Name value
    string constant internal EIP712_DOMAIN_NAME = "0x Protocol";

    // EIP712 Domain Version value
    string constant internal EIP712_DOMAIN_VERSION = "2";

    // Hash of the EIP712 Domain Separator Schema
    bytes32 constant internal EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH = keccak256(abi.encodePacked(
        "EIP712Domain(",
        "string name,",
        "string version,",
        "address verifyingContract",
        ")"
    ));

    // Hash of the EIP712 Domain Separator data
    // solhint-disable-next-line var-name-mixedcase
    bytes32 public EIP712_DOMAIN_HASH;

    constructor ()
        public
    {
        EIP712_DOMAIN_HASH = keccak256(abi.encodePacked(
            EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH,
            keccak256(bytes(EIP712_DOMAIN_NAME)),
            keccak256(bytes(EIP712_DOMAIN_VERSION)),
            bytes32(address(this))
        ));
    }

    /// @dev Calculates EIP712 encoding for a hash struct in this EIP712 Domain.
    /// @param hashStruct The EIP712 hash struct.
    /// @return EIP712 hash applied to this EIP712 Domain.
    function hashEIP712Message(bytes32 hashStruct)
        internal
        view
        returns (bytes32 result)
    {
        bytes32 eip712DomainHash = EIP712_DOMAIN_HASH;

        // Assembly for more efficient computing:
        // keccak256(abi.encodePacked(
        //     EIP191_HEADER,
        //     EIP712_DOMAIN_HASH,
        //     hashStruct    
        // ));

        assembly {
            // Load free memory pointer
            let memPtr := mload(64)

            mstore(memPtr, 0x1901000000000000000000000000000000000000000000000000000000000000)  // EIP191 header
            mstore(add(memPtr, 2), eip712DomainHash)                                            // EIP712 domain hash
            mstore(add(memPtr, 34), hashStruct)                                                 // Hash of struct

            // Compute hash
            result := keccak256(memPtr, 66)
        }
        return result;
    }
}



contract LibOrder is
    LibEIP712
{
    // Hash for the EIP712 Order Schema
    bytes32 constant internal EIP712_ORDER_SCHEMA_HASH = keccak256(abi.encodePacked(
        "Order(",
        "address makerAddress,",
        "address takerAddress,",
        "address feeRecipientAddress,",
        "address senderAddress,",
        "uint256 makerAssetAmount,",
        "uint256 takerAssetAmount,",
        "uint256 makerFee,",
        "uint256 takerFee,",
        "uint256 expirationTimeSeconds,",
        "uint256 salt,",
        "bytes makerAssetData,",
        "bytes takerAssetData",
        ")"
    ));

    // A valid order remains fillable until it is expired, fully filled, or cancelled.
    // An order's state is unaffected by external factors, like account balances.
    enum OrderStatus {
        INVALID,                     // Default value
        INVALID_MAKER_ASSET_AMOUNT,  // Order does not have a valid maker asset amount
        INVALID_TAKER_ASSET_AMOUNT,  // Order does not have a valid taker asset amount
        FILLABLE,                    // Order is fillable
        EXPIRED,                     // Order has already expired
        FULLY_FILLED,                // Order is fully filled
        CANCELLED                    // Order has been cancelled
    }

    // solhint-disable max-line-length
    struct Order {
        address makerAddress;           // Address that created the order.      
        address takerAddress;           // Address that is allowed to fill the order. If set to 0, any address is allowed to fill the order.          
        address feeRecipientAddress;    // Address that will recieve fees when order is filled.      
        address senderAddress;          // Address that is allowed to call Exchange contract methods that affect this order. If set to 0, any address is allowed to call these methods.
        uint256 makerAssetAmount;       // Amount of makerAsset being offered by maker. Must be greater than 0.        
        uint256 takerAssetAmount;       // Amount of takerAsset being bid on by maker. Must be greater than 0.        
        uint256 makerFee;               // Amount of ZRX paid to feeRecipient by maker when order is filled. If set to 0, no transfer of ZRX from maker to feeRecipient will be attempted.
        uint256 takerFee;               // Amount of ZRX paid to feeRecipient by taker when order is filled. If set to 0, no transfer of ZRX from taker to feeRecipient will be attempted.
        uint256 expirationTimeSeconds;  // Timestamp in seconds at which order expires.          
        uint256 salt;                   // Arbitrary number to facilitate uniqueness of the order's hash.     
        bytes makerAssetData;           // Encoded data that can be decoded by a specified proxy contract when transferring makerAsset. The last byte references the id of this proxy.
        bytes takerAssetData;           // Encoded data that can be decoded by a specified proxy contract when transferring takerAsset. The last byte references the id of this proxy.
    }
    // solhint-enable max-line-length

    struct OrderInfo {
        uint8 orderStatus;                    // Status that describes order's validity and fillability.
        bytes32 orderHash;                    // EIP712 hash of the order (see LibOrder.getOrderHash).
        uint256 orderTakerAssetFilledAmount;  // Amount of order that has already been filled.
    }

    /// @dev Calculates Keccak-256 hash of the order.
    /// @param order The order structure.
    /// @return Keccak-256 EIP712 hash of the order.
    function getOrderHash(Order memory order)
        internal
        view
        returns (bytes32 orderHash)
    {
        orderHash = hashEIP712Message(hashOrder(order));
        return orderHash;
    }

    /// @dev Calculates EIP712 hash of the order.
    /// @param order The order structure.
    /// @return EIP712 hash of the order.
    function hashOrder(Order memory order)
        internal
        pure
        returns (bytes32 result)
    {
        bytes32 schemaHash = EIP712_ORDER_SCHEMA_HASH;
        bytes32 makerAssetDataHash = keccak256(order.makerAssetData);
        bytes32 takerAssetDataHash = keccak256(order.takerAssetData);

        // Assembly for more efficiently computing:
        // keccak256(abi.encodePacked(
        //     EIP712_ORDER_SCHEMA_HASH,
        //     bytes32(order.makerAddress),
        //     bytes32(order.takerAddress),
        //     bytes32(order.feeRecipientAddress),
        //     bytes32(order.senderAddress),
        //     order.makerAssetAmount,
        //     order.takerAssetAmount,
        //     order.makerFee,
        //     order.takerFee,
        //     order.expirationTimeSeconds,
        //     order.salt,
        //     keccak256(order.makerAssetData),
        //     keccak256(order.takerAssetData)
        // ));

        assembly {
            // Calculate memory addresses that will be swapped out before hashing
            let pos1 := sub(order, 32)
            let pos2 := add(order, 320)
            let pos3 := add(order, 352)

            // Backup
            let temp1 := mload(pos1)
            let temp2 := mload(pos2)
            let temp3 := mload(pos3)
            
            // Hash in place
            mstore(pos1, schemaHash)
            mstore(pos2, makerAssetDataHash)
            mstore(pos3, takerAssetDataHash)
            result := keccak256(pos1, 416)
            
            // Restore
            mstore(pos1, temp1)
            mstore(pos2, temp2)
            mstore(pos3, temp3)
        }
        return result;
    }
}

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;




contract LibMath is
    SafeMath
{
    /// @dev Calculates partial value given a numerator and denominator rounded down.
    ///      Reverts if rounding error is >= 0.1%
    /// @param numerator Numerator.
    /// @param denominator Denominator.
    /// @param target Value to calculate partial of.
    /// @return Partial value of target rounded down.
    function safeGetPartialAmountFloor(
        uint256 numerator,
        uint256 denominator,
        uint256 target
    )
        internal
        pure
        returns (uint256 partialAmount)
    {
        require(
            denominator > 0,
            "DIVISION_BY_ZERO"
        );

        require(
            !isRoundingErrorFloor(
                numerator,
                denominator,
                target
            ),
            "ROUNDING_ERROR"
        );
        
        partialAmount = safeDiv(
            safeMul(numerator, target),
            denominator
        );
        return partialAmount;
    }

    /// @dev Calculates partial value given a numerator and denominator rounded down.
    ///      Reverts if rounding error is >= 0.1%
    /// @param numerator Numerator.
    /// @param denominator Denominator.
    /// @param target Value to calculate partial of.
    /// @return Partial value of target rounded up.
    function safeGetPartialAmountCeil(
        uint256 numerator,
        uint256 denominator,
        uint256 target
    )
        internal
        pure
        returns (uint256 partialAmount)
    {
        require(
            denominator > 0,
            "DIVISION_BY_ZERO"
        );

        require(
            !isRoundingErrorCeil(
                numerator,
                denominator,
                target
            ),
            "ROUNDING_ERROR"
        );
        
        // safeDiv computes `floor(a / b)`. We use the identity (a, b integer):
        //       ceil(a / b) = floor((a + b - 1) / b)
        // To implement `ceil(a / b)` using safeDiv.
        partialAmount = safeDiv(
            safeAdd(
                safeMul(numerator, target),
                safeSub(denominator, 1)
            ),
            denominator
        );
        return partialAmount;
    }

    /// @dev Calculates partial value given a numerator and denominator rounded down.
    /// @param numerator Numerator.
    /// @param denominator Denominator.
    /// @param target Value to calculate partial of.
    /// @return Partial value of target rounded down.
    function getPartialAmountFloor(
        uint256 numerator,
        uint256 denominator,
        uint256 target
    )
        internal
        pure
        returns (uint256 partialAmount)
    {
        require(
            denominator > 0,
            "DIVISION_BY_ZERO"
        );

        partialAmount = safeDiv(
            safeMul(numerator, target),
            denominator
        );
        return partialAmount;
    }
    
    /// @dev Calculates partial value given a numerator and denominator rounded down.
    /// @param numerator Numerator.
    /// @param denominator Denominator.
    /// @param target Value to calculate partial of.
    /// @return Partial value of target rounded up.
    function getPartialAmountCeil(
        uint256 numerator,
        uint256 denominator,
        uint256 target
    )
        internal
        pure
        returns (uint256 partialAmount)
    {
        require(
            denominator > 0,
            "DIVISION_BY_ZERO"
        );

        // safeDiv computes `floor(a / b)`. We use the identity (a, b integer):
        //       ceil(a / b) = floor((a + b - 1) / b)
        // To implement `ceil(a / b)` using safeDiv.
        partialAmount = safeDiv(
            safeAdd(
                safeMul(numerator, target),
                safeSub(denominator, 1)
            ),
            denominator
        );
        return partialAmount;
    }
    
    /// @dev Checks if rounding error >= 0.1% when rounding down.
    /// @param numerator Numerator.
    /// @param denominator Denominator.
    /// @param target Value to multiply with numerator/denominator.
    /// @return Rounding error is present.
    function isRoundingErrorFloor(
        uint256 numerator,
        uint256 denominator,
        uint256 target
    )
        internal
        pure
        returns (bool isError)
    {
        require(
            denominator > 0,
            "DIVISION_BY_ZERO"
        );
        
        // The absolute rounding error is the difference between the rounded
        // value and the ideal value. The relative rounding error is the
        // absolute rounding error divided by the absolute value of the
        // ideal value. This is undefined when the ideal value is zero.
        //
        // The ideal value is `numerator * target / denominator`.
        // Let's call `numerator * target % denominator` the remainder.
        // The absolute error is `remainder / denominator`.
        //
        // When the ideal value is zero, we require the absolute error to
        // be zero. Fortunately, this is always the case. The ideal value is
        // zero iff `numerator == 0` and/or `target == 0`. In this case the
        // remainder and absolute error are also zero. 
        if (target == 0 || numerator == 0) {
            return false;
        }
        
        // Otherwise, we want the relative rounding error to be strictly
        // less than 0.1%.
        // The relative error is `remainder / (numerator * target)`.
        // We want the relative error less than 1 / 1000:
        //        remainder / (numerator * denominator)  <  1 / 1000
        // or equivalently:
        //        1000 * remainder  <  numerator * target
        // so we have a rounding error iff:
        //        1000 * remainder  >=  numerator * target
        uint256 remainder = mulmod(
            target,
            numerator,
            denominator
        );
        isError = safeMul(1000, remainder) >= safeMul(numerator, target);
        return isError;
    }
    
    /// @dev Checks if rounding error >= 0.1% when rounding up.
    /// @param numerator Numerator.
    /// @param denominator Denominator.
    /// @param target Value to multiply with numerator/denominator.
    /// @return Rounding error is present.
    function isRoundingErrorCeil(
        uint256 numerator,
        uint256 denominator,
        uint256 target
    )
        internal
        pure
        returns (bool isError)
    {
        require(
            denominator > 0,
            "DIVISION_BY_ZERO"
        );
        
        // See the comments in `isRoundingError`.
        if (target == 0 || numerator == 0) {
            // When either is zero, the ideal value and rounded value are zero
            // and there is no rounding error. (Although the relative error
            // is undefined.)
            return false;
        }
        // Compute remainder as before
        uint256 remainder = mulmod(
            target,
            numerator,
            denominator
        );
        remainder = safeSub(denominator, remainder) % denominator;
        isError = safeMul(1000, remainder) >= safeMul(numerator, target);
        return isError;
    }
}

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;



/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;





contract IExchangeCore {

    /// @dev Cancels all orders created by makerAddress with a salt less than or equal to the targetOrderEpoch
    ///      and senderAddress equal to msg.sender (or null address if msg.sender == makerAddress).
    /// @param targetOrderEpoch Orders created with a salt less or equal to this value will be cancelled.
    function cancelOrdersUpTo(uint256 targetOrderEpoch)
        external;

    /// @dev Fills the input order.
    /// @param order Order struct containing order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signature Proof that order has been created by maker.
    /// @return Amounts filled and fees paid by maker and taker.
    function fillOrder(
        LibOrder.Order memory order,
        uint256 takerAssetFillAmount,
        bytes memory signature
    )
        public
        returns (LibFillResults.FillResults memory fillResults);

    /// @dev After calling, the order can not be filled anymore.
    /// @param order Order struct containing order specifications.
    function cancelOrder(LibOrder.Order memory order)
        public;

    /// @dev Gets information about an order: status, hash, and amount filled.
    /// @param order Order to gather information on.
    /// @return OrderInfo Information about the order and its state.
    ///                   See LibOrder.OrderInfo for a complete description.
    function getOrderInfo(LibOrder.Order memory order)
        public
        view
        returns (LibOrder.OrderInfo memory orderInfo);
}



contract MExchangeCore is
    IExchangeCore
{
    // Fill event is emitted whenever an order is filled.
    event Fill(
        address indexed makerAddress,         // Address that created the order.      
        address indexed feeRecipientAddress,  // Address that received fees.
        address takerAddress,                 // Address that filled the order.
        address senderAddress,                // Address that called the Exchange contract (msg.sender).
        uint256 makerAssetFilledAmount,       // Amount of makerAsset sold by maker and bought by taker. 
        uint256 takerAssetFilledAmount,       // Amount of takerAsset sold by taker and bought by maker.
        uint256 makerFeePaid,                 // Amount of ZRX paid to feeRecipient by maker.
        uint256 takerFeePaid,                 // Amount of ZRX paid to feeRecipient by taker.
        bytes32 indexed orderHash,            // EIP712 hash of order (see LibOrder.getOrderHash).
        bytes makerAssetData,                 // Encoded data specific to makerAsset. 
        bytes takerAssetData                  // Encoded data specific to takerAsset.
    );

    // Cancel event is emitted whenever an individual order is cancelled.
    event Cancel(
        address indexed makerAddress,         // Address that created the order.      
        address indexed feeRecipientAddress,  // Address that would have recieved fees if order was filled.   
        address senderAddress,                // Address that called the Exchange contract (msg.sender).
        bytes32 indexed orderHash,            // EIP712 hash of order (see LibOrder.getOrderHash).
        bytes makerAssetData,                 // Encoded data specific to makerAsset. 
        bytes takerAssetData                  // Encoded data specific to takerAsset.
    );

    // CancelUpTo event is emitted whenever `cancelOrdersUpTo` is executed succesfully.
    event CancelUpTo(
        address indexed makerAddress,         // Orders cancelled must have been created by this address.
        address indexed senderAddress,        // Orders cancelled must have a `senderAddress` equal to this address.
        uint256 orderEpoch                    // Orders with specified makerAddress and senderAddress with a salt less than this value are considered cancelled.
    );

    /// @dev Fills the input order.
    /// @param order Order struct containing order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signature Proof that order has been created by maker.
    /// @return Amounts filled and fees paid by maker and taker.
    function fillOrderInternal(
        LibOrder.Order memory order,
        uint256 takerAssetFillAmount,
        bytes memory signature
    )
        internal
        returns (LibFillResults.FillResults memory fillResults);

    /// @dev After calling, the order can not be filled anymore.
    /// @param order Order struct containing order specifications.
    function cancelOrderInternal(LibOrder.Order memory order)
        internal;

    /// @dev Updates state with results of a fill order.
    /// @param order that was filled.
    /// @param takerAddress Address of taker who filled the order.
    /// @param orderTakerAssetFilledAmount Amount of order already filled.
    /// @return fillResults Amounts filled and fees paid by maker and taker.
    function updateFilledState(
        LibOrder.Order memory order,
        address takerAddress,
        bytes32 orderHash,
        uint256 orderTakerAssetFilledAmount,
        LibFillResults.FillResults memory fillResults
    )
        internal;

    /// @dev Updates state with results of cancelling an order.
    ///      State is only updated if the order is currently fillable.
    ///      Otherwise, updating state would have no effect.
    /// @param order that was cancelled.
    /// @param orderHash Hash of order that was cancelled.
    function updateCancelledState(
        LibOrder.Order memory order,
        bytes32 orderHash
    )
        internal;
    
    /// @dev Validates context for fillOrder. Succeeds or throws.
    /// @param order to be filled.
    /// @param orderInfo OrderStatus, orderHash, and amount already filled of order.
    /// @param takerAddress Address of order taker.
    /// @param signature Proof that the orders was created by its maker.
    function assertFillableOrder(
        LibOrder.Order memory order,
        LibOrder.OrderInfo memory orderInfo,
        address takerAddress,
        bytes memory signature
    )
        internal
        view;
    
    /// @dev Validates context for fillOrder. Succeeds or throws.
    /// @param order to be filled.
    /// @param orderInfo Status, orderHash, and amount already filled of order.
    /// @param takerAssetFillAmount Desired amount of order to fill by taker.
    /// @param takerAssetFilledAmount Amount of takerAsset that will be filled.
    /// @param makerAssetFilledAmount Amount of makerAsset that will be transfered.
    function assertValidFill(
        LibOrder.Order memory order,
        LibOrder.OrderInfo memory orderInfo,
        uint256 takerAssetFillAmount,
        uint256 takerAssetFilledAmount,
        uint256 makerAssetFilledAmount
    )
        internal
        view;

    /// @dev Validates context for cancelOrder. Succeeds or throws.
    /// @param order to be cancelled.
    /// @param orderInfo OrderStatus, orderHash, and amount already filled of order.
    function assertValidCancel(
        LibOrder.Order memory order,
        LibOrder.OrderInfo memory orderInfo
    )
        internal
        view;

    /// @dev Calculates amounts filled and fees paid by maker and taker.
    /// @param order to be filled.
    /// @param takerAssetFilledAmount Amount of takerAsset that will be filled.
    /// @return fillResults Amounts filled and fees paid by maker and taker.
    function calculateFillResults(
        LibOrder.Order memory order,
        uint256 takerAssetFilledAmount
    )
        internal
        pure
        returns (LibFillResults.FillResults memory fillResults);

}

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;


contract ISignatureValidator {

    /// @dev Approves a hash on-chain using any valid signature type.
    ///      After presigning a hash, the preSign signature type will become valid for that hash and signer.
    /// @param signerAddress Address that should have signed the given hash.
    /// @param signature Proof that the hash has been signed by signer.
    function preSign(
        bytes32 hash,
        address signerAddress,
        bytes signature
    )
        external;
    
    /// @dev Approves/unnapproves a Validator contract to verify signatures on signer's behalf.
    /// @param validatorAddress Address of Validator contract.
    /// @param approval Approval or disapproval of  Validator contract.
    function setSignatureValidatorApproval(
        address validatorAddress,
        bool approval
    )
        external;

    /// @dev Verifies that a signature is valid.
    /// @param hash Message hash that is signed.
    /// @param signerAddress Address of signer.
    /// @param signature Proof of signing.
    /// @return Validity of order signature.
    function isValidSignature(
        bytes32 hash,
        address signerAddress,
        bytes memory signature
    )
        public
        view
        returns (bool isValid);
}



contract MSignatureValidator is
    ISignatureValidator
{
    event SignatureValidatorApproval(
        address indexed signerAddress,     // Address that approves or disapproves a contract to verify signatures.
        address indexed validatorAddress,  // Address of signature validator contract.
        bool approved                      // Approval or disapproval of validator contract.
    );

    // Allowed signature types.
    enum SignatureType {
        Illegal,         // 0x00, default value
        Invalid,         // 0x01
        EIP712,          // 0x02
        EthSign,         // 0x03
        Wallet,          // 0x04
        Validator,       // 0x05
        PreSigned,       // 0x06
        NSignatureTypes  // 0x07, number of signature types. Always leave at end.
    }

    /// @dev Verifies signature using logic defined by Wallet contract.
    /// @param hash Any 32 byte hash.
    /// @param walletAddress Address that should have signed the given hash
    ///                      and defines its own signature verification method.
    /// @param signature Proof that the hash has been signed by signer.
    /// @return True if the address recovered from the provided signature matches the input signer address.
    function isValidWalletSignature(
        bytes32 hash,
        address walletAddress,
        bytes signature
    )
        internal
        view
        returns (bool isValid);

    /// @dev Verifies signature using logic defined by Validator contract.
    /// @param validatorAddress Address of validator contract.
    /// @param hash Any 32 byte hash.
    /// @param signerAddress Address that should have signed the given hash.
    /// @param signature Proof that the hash has been signed by signer.
    /// @return True if the address recovered from the provided signature matches the input signer address.
    function isValidValidatorSignature(
        address validatorAddress,
        bytes32 hash,
        address signerAddress,
        bytes signature
    )
        internal
        view
        returns (bool isValid);
}

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/
pragma solidity 0.4.24;

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/
pragma solidity 0.4.24;


contract ITransactions {

    /// @dev Executes an exchange method call in the context of signer.
    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
    /// @param signerAddress Address of transaction signer.
    /// @param data AbiV2 encoded calldata.
    /// @param signature Proof of signer transaction by signer.
    function executeTransaction(
        uint256 salt,
        address signerAddress,
        bytes data,
        bytes signature
    )
        external;
}



contract MTransactions is
    ITransactions
{
    // Hash for the EIP712 ZeroEx Transaction Schema
    bytes32 constant internal EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH = keccak256(abi.encodePacked(
        "ZeroExTransaction(",
        "uint256 salt,",
        "address signerAddress,",
        "bytes data",
        ")"
    ));

    /// @dev Calculates EIP712 hash of the Transaction.
    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
    /// @param signerAddress Address of transaction signer.
    /// @param data AbiV2 encoded calldata.
    /// @return EIP712 hash of the Transaction.
    function hashZeroExTransaction(
        uint256 salt,
        address signerAddress,
        bytes memory data
    )
        internal
        pure
        returns (bytes32 result);

    /// @dev The current function will be called in the context of this address (either 0x transaction signer or `msg.sender`).
    ///      If calling a fill function, this address will represent the taker.
    ///      If calling a cancel function, this address will represent the maker.
    /// @return Signer of 0x transaction if entry point is `executeTransaction`.
    ///         `msg.sender` if entry point is any other function.
    function getCurrentContextAddress()
        internal
        view
        returns (address);
}

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;


contract IAssetProxyDispatcher {

    /// @dev Registers an asset proxy to its asset proxy id.
    ///      Once an asset proxy is registered, it cannot be unregistered.
    /// @param assetProxy Address of new asset proxy to register.
    function registerAssetProxy(address assetProxy)
        external;

    /// @dev Gets an asset proxy.
    /// @param assetProxyId Id of the asset proxy.
    /// @return The asset proxy registered to assetProxyId. Returns 0x0 if no proxy is registered.
    function getAssetProxy(bytes4 assetProxyId)
        external
        view
        returns (address);
}



contract MAssetProxyDispatcher is
    IAssetProxyDispatcher
{
    // Logs registration of new asset proxy
    event AssetProxyRegistered(
        bytes4 id,              // Id of new registered AssetProxy.
        address assetProxy      // Address of new registered AssetProxy.
    );

    /// @dev Forwards arguments to assetProxy and calls `transferFrom`. Either succeeds or throws.
    /// @param assetData Byte array encoded for the asset.
    /// @param from Address to transfer token from.
    /// @param to Address to transfer token to.
    /// @param amount Amount of token to transfer.
    function dispatchTransferFrom(
        bytes memory assetData,
        address from,
        address to,
        uint256 amount
    )
        internal;
}



contract MixinExchangeCore is
    ReentrancyGuard,
    LibConstants,
    LibMath,
    LibOrder,
    LibFillResults,
    MAssetProxyDispatcher,
    MExchangeCore,
    MSignatureValidator,
    MTransactions
{
    // Mapping of orderHash => amount of takerAsset already bought by maker
    mapping (bytes32 => uint256) public filled;

    // Mapping of orderHash => cancelled
    mapping (bytes32 => bool) public cancelled;

    // Mapping of makerAddress => senderAddress => lowest salt an order can have in order to be fillable
    // Orders with specified senderAddress and with a salt less than their epoch are considered cancelled
    mapping (address => mapping (address => uint256)) public orderEpoch;

    /// @dev Cancels all orders created by makerAddress with a salt less than or equal to the targetOrderEpoch
    ///      and senderAddress equal to msg.sender (or null address if msg.sender == makerAddress).
    /// @param targetOrderEpoch Orders created with a salt less or equal to this value will be cancelled.
    function cancelOrdersUpTo(uint256 targetOrderEpoch)
        external
        nonReentrant
    {
        address makerAddress = getCurrentContextAddress();
        // If this function is called via `executeTransaction`, we only update the orderEpoch for the makerAddress/msg.sender combination.
        // This allows external filter contracts to add rules to how orders are cancelled via this function.
        address senderAddress = makerAddress == msg.sender ? address(0) : msg.sender;

        // orderEpoch is initialized to 0, so to cancelUpTo we need salt + 1
        uint256 newOrderEpoch = targetOrderEpoch + 1;
        uint256 oldOrderEpoch = orderEpoch[makerAddress][senderAddress];

        // Ensure orderEpoch is monotonically increasing
        require(
            newOrderEpoch > oldOrderEpoch,
            "INVALID_NEW_ORDER_EPOCH"
        );

        // Update orderEpoch
        orderEpoch[makerAddress][senderAddress] = newOrderEpoch;
        emit CancelUpTo(
            makerAddress,
            senderAddress,
            newOrderEpoch
        );
    }

    /// @dev Fills the input order.
    /// @param order Order struct containing order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signature Proof that order has been created by maker.
    /// @return Amounts filled and fees paid by maker and taker.
    function fillOrder(
        Order memory order,
        uint256 takerAssetFillAmount,
        bytes memory signature
    )
        public
        nonReentrant
        returns (FillResults memory fillResults)
    {
        fillResults = fillOrderInternal(
            order,
            takerAssetFillAmount,
            signature
        );
        return fillResults;
    }

    /// @dev After calling, the order can not be filled anymore.
    ///      Throws if order is invalid or sender does not have permission to cancel.
    /// @param order Order to cancel. Order must be OrderStatus.FILLABLE.
    function cancelOrder(Order memory order)
        public
        nonReentrant
    {
        cancelOrderInternal(order);
    }

    /// @dev Gets information about an order: status, hash, and amount filled.
    /// @param order Order to gather information on.
    /// @return OrderInfo Information about the order and its state.
    ///         See LibOrder.OrderInfo for a complete description.
    function getOrderInfo(Order memory order)
        public
        view
        returns (OrderInfo memory orderInfo)
    {
        // Compute the order hash
        orderInfo.orderHash = getOrderHash(order);

        // Fetch filled amount
        orderInfo.orderTakerAssetFilledAmount = filled[orderInfo.orderHash];

        // If order.makerAssetAmount is zero, we also reject the order.
        // While the Exchange contract handles them correctly, they create
        // edge cases in the supporting infrastructure because they have
        // an 'infinite' price when computed by a simple division.
        if (order.makerAssetAmount == 0) {
            orderInfo.orderStatus = uint8(OrderStatus.INVALID_MAKER_ASSET_AMOUNT);
            return orderInfo;
        }

        // If order.takerAssetAmount is zero, then the order will always
        // be considered filled because 0 == takerAssetAmount == orderTakerAssetFilledAmount
        // Instead of distinguishing between unfilled and filled zero taker
        // amount orders, we choose not to support them.
        if (order.takerAssetAmount == 0) {
            orderInfo.orderStatus = uint8(OrderStatus.INVALID_TAKER_ASSET_AMOUNT);
            return orderInfo;
        }

        // Validate order availability
        if (orderInfo.orderTakerAssetFilledAmount >= order.takerAssetAmount) {
            orderInfo.orderStatus = uint8(OrderStatus.FULLY_FILLED);
            return orderInfo;
        }

        // Validate order expiration
        // solhint-disable-next-line not-rely-on-time
        if (block.timestamp >= order.expirationTimeSeconds) {
            orderInfo.orderStatus = uint8(OrderStatus.EXPIRED);
            return orderInfo;
        }

        // Check if order has been cancelled
        if (cancelled[orderInfo.orderHash]) {
            orderInfo.orderStatus = uint8(OrderStatus.CANCELLED);
            return orderInfo;
        }
        if (orderEpoch[order.makerAddress][order.senderAddress] > order.salt) {
            orderInfo.orderStatus = uint8(OrderStatus.CANCELLED);
            return orderInfo;
        }

        // All other statuses are ruled out: order is Fillable
        orderInfo.orderStatus = uint8(OrderStatus.FILLABLE);
        return orderInfo;
    }

    /// @dev Fills the input order.
    /// @param order Order struct containing order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signature Proof that order has been created by maker.
    /// @return Amounts filled and fees paid by maker and taker.
    function fillOrderInternal(
        Order memory order,
        uint256 takerAssetFillAmount,
        bytes memory signature
    )
        internal
        returns (FillResults memory fillResults)
    {
        // Fetch order info
        OrderInfo memory orderInfo = getOrderInfo(order);

        // Fetch taker address
        address takerAddress = getCurrentContextAddress();

        // Assert that the order is fillable by taker
        assertFillableOrder(
            order,
            orderInfo,
            takerAddress,
            signature
        );

        // Get amount of takerAsset to fill
        uint256 remainingTakerAssetAmount = safeSub(order.takerAssetAmount, orderInfo.orderTakerAssetFilledAmount);
        uint256 takerAssetFilledAmount = min256(takerAssetFillAmount, remainingTakerAssetAmount);

        // Validate context
        assertValidFill(
            order,
            orderInfo,
            takerAssetFillAmount,
            takerAssetFilledAmount,
            fillResults.makerAssetFilledAmount
        );

        // Compute proportional fill amounts
        fillResults = calculateFillResults(order, takerAssetFilledAmount);

        // Update exchange internal state
        updateFilledState(
            order,
            takerAddress,
            orderInfo.orderHash,
            orderInfo.orderTakerAssetFilledAmount,
            fillResults
        );

        // Settle order
        settleOrder(
            order,
            takerAddress,
            fillResults
        );

        return fillResults;
    }

    /// @dev After calling, the order can not be filled anymore.
    ///      Throws if order is invalid or sender does not have permission to cancel.
    /// @param order Order to cancel. Order must be OrderStatus.FILLABLE.
    function cancelOrderInternal(Order memory order)
        internal
    {
        // Fetch current order status
        OrderInfo memory orderInfo = getOrderInfo(order);

        // Validate context
        assertValidCancel(order, orderInfo);

        // Perform cancel
        updateCancelledState(order, orderInfo.orderHash);
    }

    /// @dev Updates state with results of a fill order.
    /// @param order that was filled.
    /// @param takerAddress Address of taker who filled the order.
    /// @param orderTakerAssetFilledAmount Amount of order already filled.
    function updateFilledState(
        Order memory order,
        address takerAddress,
        bytes32 orderHash,
        uint256 orderTakerAssetFilledAmount,
        FillResults memory fillResults
    )
        internal
    {
        // Update state
        filled[orderHash] = safeAdd(orderTakerAssetFilledAmount, fillResults.takerAssetFilledAmount);

        // Log order
        emit Fill(
            order.makerAddress,
            order.feeRecipientAddress,
            takerAddress,
            msg.sender,
            fillResults.makerAssetFilledAmount,
            fillResults.takerAssetFilledAmount,
            fillResults.makerFeePaid,
            fillResults.takerFeePaid,
            orderHash,
            order.makerAssetData,
            order.takerAssetData
        );
    }

    /// @dev Updates state with results of cancelling an order.
    ///      State is only updated if the order is currently fillable.
    ///      Otherwise, updating state would have no effect.
    /// @param order that was cancelled.
    /// @param orderHash Hash of order that was cancelled.
    function updateCancelledState(
        Order memory order,
        bytes32 orderHash
    )
        internal
    {
        // Perform cancel
        cancelled[orderHash] = true;

        // Log cancel
        emit Cancel(
            order.makerAddress,
            order.feeRecipientAddress,
            msg.sender,
            orderHash,
            order.makerAssetData,
            order.takerAssetData
        );
    }

    /// @dev Validates context for fillOrder. Succeeds or throws.
    /// @param order to be filled.
    /// @param orderInfo OrderStatus, orderHash, and amount already filled of order.
    /// @param takerAddress Address of order taker.
    /// @param signature Proof that the orders was created by its maker.
    function assertFillableOrder(
        Order memory order,
        OrderInfo memory orderInfo,
        address takerAddress,
        bytes memory signature
    )
        internal
        view
    {
        // An order can only be filled if its status is FILLABLE.
        require(
            orderInfo.orderStatus == uint8(OrderStatus.FILLABLE),
            "ORDER_UNFILLABLE"
        );

        // Validate sender is allowed to fill this order
        if (order.senderAddress != address(0)) {
            require(
                order.senderAddress == msg.sender,
                "INVALID_SENDER"
            );
        }

        // Validate taker is allowed to fill this order
        if (order.takerAddress != address(0)) {
            require(
                order.takerAddress == takerAddress,
                "INVALID_TAKER"
            );
        }

        // Validate Maker signature (check only if first time seen)
        if (orderInfo.orderTakerAssetFilledAmount == 0) {
            require(
                isValidSignature(
                    orderInfo.orderHash,
                    order.makerAddress,
                    signature
                ),
                "INVALID_ORDER_SIGNATURE"
            );
        }
    }

    /// @dev Validates context for fillOrder. Succeeds or throws.
    /// @param order to be filled.
    /// @param orderInfo OrderStatus, orderHash, and amount already filled of order.
    /// @param takerAssetFillAmount Desired amount of order to fill by taker.
    /// @param takerAssetFilledAmount Amount of takerAsset that will be filled.
    /// @param makerAssetFilledAmount Amount of makerAsset that will be transfered.
    function assertValidFill(
        Order memory order,
        OrderInfo memory orderInfo,
        uint256 takerAssetFillAmount,  // TODO: use FillResults
        uint256 takerAssetFilledAmount,
        uint256 makerAssetFilledAmount
    )
        internal
        view
    {
        // Revert if fill amount is invalid
        // TODO: reconsider necessity for v2.1
        require(
            takerAssetFillAmount != 0,
            "INVALID_TAKER_AMOUNT"
        );

        // Make sure taker does not pay more than desired amount
        // NOTE: This assertion should never fail, it is here
        //       as an extra defence against potential bugs.
        require(
            takerAssetFilledAmount <= takerAssetFillAmount,
            "TAKER_OVERPAY"
        );

        // Make sure order is not overfilled
        // NOTE: This assertion should never fail, it is here
        //       as an extra defence against potential bugs.
        require(
            safeAdd(orderInfo.orderTakerAssetFilledAmount, takerAssetFilledAmount) <= order.takerAssetAmount,
            "ORDER_OVERFILL"
        );

        // Make sure order is filled at acceptable price.
        // The order has an implied price from the makers perspective:
        //    order price = order.makerAssetAmount / order.takerAssetAmount
        // i.e. the number of makerAsset maker is paying per takerAsset. The
        // maker is guaranteed to get this price or a better (lower) one. The
        // actual price maker is getting in this fill is:
        //    fill price = makerAssetFilledAmount / takerAssetFilledAmount
        // We need `fill price <= order price` for the fill to be fair to maker.
        // This amounts to:
        //     makerAssetFilledAmount        order.makerAssetAmount
        //    ------------------------  <=  -----------------------
        //     takerAssetFilledAmount        order.takerAssetAmount
        // or, equivalently:
        //     makerAssetFilledAmount * order.takerAssetAmount <=
        //     order.makerAssetAmount * takerAssetFilledAmount
        // NOTE: This assertion should never fail, it is here
        //       as an extra defence against potential bugs.
        require(
            safeMul(makerAssetFilledAmount, order.takerAssetAmount)
            <=
            safeMul(order.makerAssetAmount, takerAssetFilledAmount),
            "INVALID_FILL_PRICE"
        );
    }

    /// @dev Validates context for cancelOrder. Succeeds or throws.
    /// @param order to be cancelled.
    /// @param orderInfo OrderStatus, orderHash, and amount already filled of order.
    function assertValidCancel(
        Order memory order,
        OrderInfo memory orderInfo
    )
        internal
        view
    {
        // Ensure order is valid
        // An order can only be cancelled if its status is FILLABLE.
        require(
            orderInfo.orderStatus == uint8(OrderStatus.FILLABLE),
            "ORDER_UNFILLABLE"
        );

        // Validate sender is allowed to cancel this order
        if (order.senderAddress != address(0)) {
            require(
                order.senderAddress == msg.sender,
                "INVALID_SENDER"
            );
        }

        // Validate transaction signed by maker
        address makerAddress = getCurrentContextAddress();
        require(
            order.makerAddress == makerAddress,
            "INVALID_MAKER"
        );
    }

    /// @dev Calculates amounts filled and fees paid by maker and taker.
    /// @param order to be filled.
    /// @param takerAssetFilledAmount Amount of takerAsset that will be filled.
    /// @return fillResults Amounts filled and fees paid by maker and taker.
    function calculateFillResults(
        Order memory order,
        uint256 takerAssetFilledAmount
    )
        internal
        pure
        returns (FillResults memory fillResults)
    {
        // Compute proportional transfer amounts
        fillResults.takerAssetFilledAmount = takerAssetFilledAmount;
        fillResults.makerAssetFilledAmount = safeGetPartialAmountFloor(
            takerAssetFilledAmount,
            order.takerAssetAmount,
            order.makerAssetAmount
        );
        fillResults.makerFeePaid = safeGetPartialAmountFloor(
            fillResults.makerAssetFilledAmount,
            order.makerAssetAmount,
            order.makerFee
        );
        fillResults.takerFeePaid = safeGetPartialAmountFloor(
            takerAssetFilledAmount,
            order.takerAssetAmount,
            order.takerFee
        );

        return fillResults;
    }

    /// @dev Settles an order by transferring assets between counterparties.
    /// @param order Order struct containing order specifications.
    /// @param takerAddress Address selling takerAsset and buying makerAsset.
    /// @param fillResults Amounts to be filled and fees paid by maker and taker.
    function settleOrder(
        LibOrder.Order memory order,
        address takerAddress,
        LibFillResults.FillResults memory fillResults
    )
        private
    {
        bytes memory zrxAssetData = ZRX_ASSET_DATA;
        dispatchTransferFrom(
            order.makerAssetData,
            order.makerAddress,
            takerAddress,
            fillResults.makerAssetFilledAmount
        );
        dispatchTransferFrom(
            order.takerAssetData,
            takerAddress,
            order.makerAddress,
            fillResults.takerAssetFilledAmount
        );
        dispatchTransferFrom(
            zrxAssetData,
            order.makerAddress,
            order.feeRecipientAddress,
            fillResults.makerFeePaid
        );
        dispatchTransferFrom(
            zrxAssetData,
            takerAddress,
            order.feeRecipientAddress,
            fillResults.takerFeePaid
        );
    }
}

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;


library LibBytes {

    using LibBytes for bytes;

    /// @dev Gets the memory address for a byte array.
    /// @param input Byte array to lookup.
    /// @return memoryAddress Memory address of byte array. This
    ///         points to the header of the byte array which contains
    ///         the length.
    function rawAddress(bytes memory input)
        internal
        pure
        returns (uint256 memoryAddress)
    {
        assembly {
            memoryAddress := input
        }
        return memoryAddress;
    }
    
    /// @dev Gets the memory address for the contents of a byte array.
    /// @param input Byte array to lookup.
    /// @return memoryAddress Memory address of the contents of the byte array.
    function contentAddress(bytes memory input)
        internal
        pure
        returns (uint256 memoryAddress)
    {
        assembly {
            memoryAddress := add(input, 32)
        }
        return memoryAddress;
    }

    /// @dev Copies `length` bytes from memory location `source` to `dest`.
    /// @param dest memory address to copy bytes to.
    /// @param source memory address to copy bytes from.
    /// @param length number of bytes to copy.
    function memCopy(
        uint256 dest,
        uint256 source,
        uint256 length
    )
        internal
        pure
    {
        if (length < 32) {
            // Handle a partial word by reading destination and masking
            // off the bits we are interested in.
            // This correctly handles overlap, zero lengths and source == dest
            assembly {
                let mask := sub(exp(256, sub(32, length)), 1)
                let s := and(mload(source), not(mask))
                let d := and(mload(dest), mask)
                mstore(dest, or(s, d))
            }
        } else {
            // Skip the O(length) loop when source == dest.
            if (source == dest) {
                return;
            }

            // For large copies we copy whole words at a time. The final
            // word is aligned to the end of the range (instead of after the
            // previous) to handle partial words. So a copy will look like this:
            //
            //  ####
            //      ####
            //          ####
            //            ####
            //
            // We handle overlap in the source and destination range by
            // changing the copying direction. This prevents us from
            // overwriting parts of source that we still need to copy.
            //
            // This correctly handles source == dest
            //
            if (source > dest) {
                assembly {
                    // We subtract 32 from `sEnd` and `dEnd` because it
                    // is easier to compare with in the loop, and these
                    // are also the addresses we need for copying the
                    // last bytes.
                    length := sub(length, 32)
                    let sEnd := add(source, length)
                    let dEnd := add(dest, length)

                    // Remember the last 32 bytes of source
                    // This needs to be done here and not after the loop
                    // because we may have overwritten the last bytes in
                    // source already due to overlap.
                    let last := mload(sEnd)

                    // Copy whole words front to back
                    // Note: the first check is always true,
                    // this could have been a do-while loop.
                    // solhint-disable-next-line no-empty-blocks
                    for {} lt(source, sEnd) {} {
                        mstore(dest, mload(source))
                        source := add(source, 32)
                        dest := add(dest, 32)
                    }
                    
                    // Write the last 32 bytes
                    mstore(dEnd, last)
                }
            } else {
                assembly {
                    // We subtract 32 from `sEnd` and `dEnd` because those
                    // are the starting points when copying a word at the end.
                    length := sub(length, 32)
                    let sEnd := add(source, length)
                    let dEnd := add(dest, length)

                    // Remember the first 32 bytes of source
                    // This needs to be done here and not after the loop
                    // because we may have overwritten the first bytes in
                    // source already due to overlap.
                    let first := mload(source)

                    // Copy whole words back to front
                    // We use a signed comparisson here to allow dEnd to become
                    // negative (happens when source and dest < 32). Valid
                    // addresses in local memory will never be larger than
                    // 2**255, so they can be safely re-interpreted as signed.
                    // Note: the first check is always true,
                    // this could have been a do-while loop.
                    // solhint-disable-next-line no-empty-blocks
                    for {} slt(dest, dEnd) {} {
                        mstore(dEnd, mload(sEnd))
                        sEnd := sub(sEnd, 32)
                        dEnd := sub(dEnd, 32)
                    }
                    
                    // Write the first 32 bytes
                    mstore(dest, first)
                }
            }
        }
    }

    /// @dev Returns a slices from a byte array.
    /// @param b The byte array to take a slice from.
    /// @param from The starting index for the slice (inclusive).
    /// @param to The final index for the slice (exclusive).
    /// @return result The slice containing bytes at indices [from, to)
    function slice(
        bytes memory b,
        uint256 from,
        uint256 to
    )
        internal
        pure
        returns (bytes memory result)
    {
        require(
            from <= to,
            "FROM_LESS_THAN_TO_REQUIRED"
        );
        require(
            to < b.length,
            "TO_LESS_THAN_LENGTH_REQUIRED"
        );
        
        // Create a new bytes structure and copy contents
        result = new bytes(to - from);
        memCopy(
            result.contentAddress(),
            b.contentAddress() + from,
            result.length
        );
        return result;
    }
    
    /// @dev Returns a slice from a byte array without preserving the input.
    /// @param b The byte array to take a slice from. Will be destroyed in the process.
    /// @param from The starting index for the slice (inclusive).
    /// @param to The final index for the slice (exclusive).
    /// @return result The slice containing bytes at indices [from, to)
    /// @dev When `from == 0`, the original array will match the slice. In other cases its state will be corrupted.
    function sliceDestructive(
        bytes memory b,
        uint256 from,
        uint256 to
    )
        internal
        pure
        returns (bytes memory result)
    {
        require(
            from <= to,
            "FROM_LESS_THAN_TO_REQUIRED"
        );
        require(
            to < b.length,
            "TO_LESS_THAN_LENGTH_REQUIRED"
        );
        
        // Create a new bytes structure around [from, to) in-place.
        assembly {
            result := add(b, from)
            mstore(result, sub(to, from))
        }
        return result;
    }

    /// @dev Pops the last byte off of a byte array by modifying its length.
    /// @param b Byte array that will be modified.
    /// @return The byte that was popped off.
    function popLastByte(bytes memory b)
        internal
        pure
        returns (bytes1 result)
    {
        require(
            b.length > 0,
            "GREATER_THAN_ZERO_LENGTH_REQUIRED"
        );

        // Store last byte.
        result = b[b.length - 1];

        assembly {
            // Decrement length of byte array.
            let newLen := sub(mload(b), 1)
            mstore(b, newLen)
        }
        return result;
    }

    /// @dev Pops the last 20 bytes off of a byte array by modifying its length.
    /// @param b Byte array that will be modified.
    /// @return The 20 byte address that was popped off.
    function popLast20Bytes(bytes memory b)
        internal
        pure
        returns (address result)
    {
        require(
            b.length >= 20,
            "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED"
        );

        // Store last 20 bytes.
        result = readAddress(b, b.length - 20);

        assembly {
            // Subtract 20 from byte array length.
            let newLen := sub(mload(b), 20)
            mstore(b, newLen)
        }
        return result;
    }

    /// @dev Tests equality of two byte arrays.
    /// @param lhs First byte array to compare.
    /// @param rhs Second byte array to compare.
    /// @return True if arrays are the same. False otherwise.
    function equals(
        bytes memory lhs,
        bytes memory rhs
    )
        internal
        pure
        returns (bool equal)
    {
        // Keccak gas cost is 30 + numWords * 6. This is a cheap way to compare.
        // We early exit on unequal lengths, but keccak would also correctly
        // handle this.
        return lhs.length == rhs.length && keccak256(lhs) == keccak256(rhs);
    }

    /// @dev Reads an address from a position in a byte array.
    /// @param b Byte array containing an address.
    /// @param index Index in byte array of address.
    /// @return address from byte array.
    function readAddress(
        bytes memory b,
        uint256 index
    )
        internal
        pure
        returns (address result)
    {
        require(
            b.length >= index + 20,  // 20 is length of address
            "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED"
        );

        // Add offset to index:
        // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
        // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)
        index += 20;

        // Read address from array memory
        assembly {
            // 1. Add index to address of bytes array
            // 2. Load 32-byte word from memory
            // 3. Apply 20-byte mask to obtain address
            result := and(mload(add(b, index)), 0xffffffffffffffffffffffffffffffffffffffff)
        }
        return result;
    }

    /// @dev Writes an address into a specific position in a byte array.
    /// @param b Byte array to insert address into.
    /// @param index Index in byte array of address.
    /// @param input Address to put into byte array.
    function writeAddress(
        bytes memory b,
        uint256 index,
        address input
    )
        internal
        pure
    {
        require(
            b.length >= index + 20,  // 20 is length of address
            "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED"
        );

        // Add offset to index:
        // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
        // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)
        index += 20;

        // Store address into array memory
        assembly {
            // The address occupies 20 bytes and mstore stores 32 bytes.
            // First fetch the 32-byte word where we'll be storing the address, then
            // apply a mask so we have only the bytes in the word that the address will not occupy.
            // Then combine these bytes with the address and store the 32 bytes back to memory with mstore.

            // 1. Add index to address of bytes array
            // 2. Load 32-byte word from memory
            // 3. Apply 12-byte mask to obtain extra bytes occupying word of memory where we'll store the address
            let neighbors := and(
                mload(add(b, index)),
                0xffffffffffffffffffffffff0000000000000000000000000000000000000000
            )
            
            // Make sure input address is clean.
            // (Solidity does not guarantee this)
            input := and(input, 0xffffffffffffffffffffffffffffffffffffffff)

            // Store the neighbors and address into memory
            mstore(add(b, index), xor(input, neighbors))
        }
    }

    /// @dev Reads a bytes32 value from a position in a byte array.
    /// @param b Byte array containing a bytes32 value.
    /// @param index Index in byte array of bytes32 value.
    /// @return bytes32 value from byte array.
    function readBytes32(
        bytes memory b,
        uint256 index
    )
        internal
        pure
        returns (bytes32 result)
    {
        require(
            b.length >= index + 32,
            "GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED"
        );

        // Arrays are prefixed by a 256 bit length parameter
        index += 32;

        // Read the bytes32 from array memory
        assembly {
            result := mload(add(b, index))
        }
        return result;
    }

    /// @dev Writes a bytes32 into a specific position in a byte array.
    /// @param b Byte array to insert <input> into.
    /// @param index Index in byte array of <input>.
    /// @param input bytes32 to put into byte array.
    function writeBytes32(
        bytes memory b,
        uint256 index,
        bytes32 input
    )
        internal
        pure
    {
        require(
            b.length >= index + 32,
            "GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED"
        );

        // Arrays are prefixed by a 256 bit length parameter
        index += 32;

        // Read the bytes32 from array memory
        assembly {
            mstore(add(b, index), input)
        }
    }

    /// @dev Reads a uint256 value from a position in a byte array.
    /// @param b Byte array containing a uint256 value.
    /// @param index Index in byte array of uint256 value.
    /// @return uint256 value from byte array.
    function readUint256(
        bytes memory b,
        uint256 index
    )
        internal
        pure
        returns (uint256 result)
    {
        result = uint256(readBytes32(b, index));
        return result;
    }

    /// @dev Writes a uint256 into a specific position in a byte array.
    /// @param b Byte array to insert <input> into.
    /// @param index Index in byte array of <input>.
    /// @param input uint256 to put into byte array.
    function writeUint256(
        bytes memory b,
        uint256 index,
        uint256 input
    )
        internal
        pure
    {
        writeBytes32(b, index, bytes32(input));
    }

    /// @dev Reads an unpadded bytes4 value from a position in a byte array.
    /// @param b Byte array containing a bytes4 value.
    /// @param index Index in byte array of bytes4 value.
    /// @return bytes4 value from byte array.
    function readBytes4(
        bytes memory b,
        uint256 index
    )
        internal
        pure
        returns (bytes4 result)
    {
        require(
            b.length >= index + 4,
            "GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED"
        );

        // Arrays are prefixed by a 32 byte length field
        index += 32;

        // Read the bytes4 from array memory
        assembly {
            result := mload(add(b, index))
            // Solidity does not require us to clean the trailing bytes.
            // We do it anyway
            result := and(result, 0xFFFFFFFF00000000000000000000000000000000000000000000000000000000)
        }
        return result;
    }

    /// @dev Reads nested bytes from a specific position.
    /// @dev NOTE: the returned value overlaps with the input value.
    ///            Both should be treated as immutable.
    /// @param b Byte array containing nested bytes.
    /// @param index Index of nested bytes.
    /// @return result Nested bytes.
    function readBytesWithLength(
        bytes memory b,
        uint256 index
    )
        internal
        pure
        returns (bytes memory result)
    {
        // Read length of nested bytes
        uint256 nestedBytesLength = readUint256(b, index);
        index += 32;

        // Assert length of <b> is valid, given
        // length of nested bytes
        require(
            b.length >= index + nestedBytesLength,
            "GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED"
        );
        
        // Return a pointer to the byte array as it exists inside `b`
        assembly {
            result := add(b, index)
        }
        return result;
    }

    /// @dev Inserts bytes at a specific position in a byte array.
    /// @param b Byte array to insert <input> into.
    /// @param index Index in byte array of <input>.
    /// @param input bytes to insert.
    function writeBytesWithLength(
        bytes memory b,
        uint256 index,
        bytes memory input
    )
        internal
        pure
    {
        // Assert length of <b> is valid, given
        // length of input
        require(
            b.length >= index + 32 + input.length,  // 32 bytes to store length
            "GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED"
        );

        // Copy <input> into <b>
        memCopy(
            b.contentAddress() + index,
            input.rawAddress(), // includes length of <input>
            input.length + 32   // +32 bytes to store <input> length
        );
    }

    /// @dev Performs a deep copy of a byte array onto another byte array of greater than or equal length.
    /// @param dest Byte array that will be overwritten with source bytes.
    /// @param source Byte array to copy onto dest bytes.
    function deepCopyBytes(
        bytes memory dest,
        bytes memory source
    )
        internal
        pure
    {
        uint256 sourceLen = source.length;
        // Dest length must be >= source length, or some bytes would not be copied.
        require(
            dest.length >= sourceLen,
            "GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED"
        );
        memCopy(
            dest.contentAddress(),
            source.contentAddress(),
            sourceLen
        );
    }
}




/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;


contract IWallet {

    /// @dev Verifies that a signature is valid.
    /// @param hash Message hash that is signed.
    /// @param signature Proof of signing.
    /// @return Validity of order signature.
    function isValidSignature(
        bytes32 hash,
        bytes signature
    )
        external
        view
        returns (bool isValid);
}

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;


contract IValidator {

    /// @dev Verifies that a signature is valid.
    /// @param hash Message hash that is signed.
    /// @param signerAddress Address that should have signed the given hash.
    /// @param signature Proof of signing.
    /// @return Validity of order signature.
    function isValidSignature(
        bytes32 hash,
        address signerAddress,
        bytes signature
    )
        external
        view
        returns (bool isValid);
}



contract MixinSignatureValidator is
    ReentrancyGuard,
    MSignatureValidator,
    MTransactions
{
    using LibBytes for bytes;

    // Mapping of hash => signer => signed
    mapping (bytes32 => mapping (address => bool)) public preSigned;

    // Mapping of signer => validator => approved
    mapping (address => mapping (address => bool)) public allowedValidators;

    /// @dev Approves a hash on-chain using any valid signature type.
    ///      After presigning a hash, the preSign signature type will become valid for that hash and signer.
    /// @param signerAddress Address that should have signed the given hash.
    /// @param signature Proof that the hash has been signed by signer.
    function preSign(
        bytes32 hash,
        address signerAddress,
        bytes signature
    )
        external
    {
        if (signerAddress != msg.sender) {
            require(
                isValidSignature(
                    hash,
                    signerAddress,
                    signature
                ),
                "INVALID_SIGNATURE"
            );
        }
        preSigned[hash][signerAddress] = true;
    }

    /// @dev Approves/unnapproves a Validator contract to verify signatures on signer's behalf.
    /// @param validatorAddress Address of Validator contract.
    /// @param approval Approval or disapproval of  Validator contract.
    function setSignatureValidatorApproval(
        address validatorAddress,
        bool approval
    )
        external
        nonReentrant
    {
        address signerAddress = getCurrentContextAddress();
        allowedValidators[signerAddress][validatorAddress] = approval;
        emit SignatureValidatorApproval(
            signerAddress,
            validatorAddress,
            approval
        );
    }

    /// @dev Verifies that a hash has been signed by the given signer.
    /// @param hash Any 32 byte hash.
    /// @param signerAddress Address that should have signed the given hash.
    /// @param signature Proof that the hash has been signed by signer.
    /// @return True if the address recovered from the provided signature matches the input signer address.
    function isValidSignature(
        bytes32 hash,
        address signerAddress,
        bytes memory signature
    )
        public
        view
        returns (bool isValid)
    {
        require(
            signature.length > 0,
            "LENGTH_GREATER_THAN_0_REQUIRED"
        );

        // Pop last byte off of signature byte array.
        uint8 signatureTypeRaw = uint8(signature.popLastByte());

        // Ensure signature is supported
        require(
            signatureTypeRaw < uint8(SignatureType.NSignatureTypes),
            "SIGNATURE_UNSUPPORTED"
        );

        SignatureType signatureType = SignatureType(signatureTypeRaw);

        // Variables are not scoped in Solidity.
        uint8 v;
        bytes32 r;
        bytes32 s;
        address recovered;

        // Always illegal signature.
        // This is always an implicit option since a signer can create a
        // signature array with invalid type or length. We may as well make
        // it an explicit option. This aids testing and analysis. It is
        // also the initialization value for the enum type.
        if (signatureType == SignatureType.Illegal) {
            revert("SIGNATURE_ILLEGAL");

        // Always invalid signature.
        // Like Illegal, this is always implicitly available and therefore
        // offered explicitly. It can be implicitly created by providing
        // a correctly formatted but incorrect signature.
        } else if (signatureType == SignatureType.Invalid) {
            require(
                signature.length == 0,
                "LENGTH_0_REQUIRED"
            );
            isValid = false;
            return isValid;

        // Signature using EIP712
        } else if (signatureType == SignatureType.EIP712) {
            require(
                signature.length == 65,
                "LENGTH_65_REQUIRED"
            );
            v = uint8(signature[0]);
            r = signature.readBytes32(1);
            s = signature.readBytes32(33);
            recovered = ecrecover(
                hash,
                v,
                r,
                s
            );
            isValid = signerAddress == recovered;
            return isValid;

        // Signed using web3.eth_sign
        } else if (signatureType == SignatureType.EthSign) {
            require(
                signature.length == 65,
                "LENGTH_65_REQUIRED"
            );
            v = uint8(signature[0]);
            r = signature.readBytes32(1);
            s = signature.readBytes32(33);
            recovered = ecrecover(
                keccak256(abi.encodePacked(
                    "\x19Ethereum Signed Message:\n32",
                    hash
                )),
                v,
                r,
                s
            );
            isValid = signerAddress == recovered;
            return isValid;

        // Signature verified by wallet contract.
        // If used with an order, the maker of the order is the wallet contract.
        } else if (signatureType == SignatureType.Wallet) {
            isValid = isValidWalletSignature(
                hash,
                signerAddress,
                signature
            );
            return isValid;

        // Signature verified by validator contract.
        // If used with an order, the maker of the order can still be an EOA.
        // A signature using this type should be encoded as:
        // | Offset   | Length | Contents                        |
        // | 0x00     | x      | Signature to validate           |
        // | 0x00 + x | 20     | Address of validator contract   |
        // | 0x14 + x | 1      | Signature type is always "\x06" |
        } else if (signatureType == SignatureType.Validator) {
            // Pop last 20 bytes off of signature byte array.
            address validatorAddress = signature.popLast20Bytes();

            // Ensure signer has approved validator.
            if (!allowedValidators[signerAddress][validatorAddress]) {
                return false;
            }
            isValid = isValidValidatorSignature(
                validatorAddress,
                hash,
                signerAddress,
                signature
            );
            return isValid;

        // Signer signed hash previously using the preSign function.
        } else if (signatureType == SignatureType.PreSigned) {
            isValid = preSigned[hash][signerAddress];
            return isValid;
        }

        // Anything else is illegal (We do not return false because
        // the signature may actually be valid, just not in a format
        // that we currently support. In this case returning false
        // may lead the caller to incorrectly believe that the
        // signature was invalid.)
        revert("SIGNATURE_UNSUPPORTED");
    }

    /// @dev Verifies signature using logic defined by Wallet contract.
    /// @param hash Any 32 byte hash.
    /// @param walletAddress Address that should have signed the given hash
    ///                      and defines its own signature verification method.
    /// @param signature Proof that the hash has been signed by signer.
    /// @return True if signature is valid for given wallet..
    function isValidWalletSignature(
        bytes32 hash,
        address walletAddress,
        bytes signature
    )
        internal
        view
        returns (bool isValid)
    {
        bytes memory calldata = abi.encodeWithSelector(
            IWallet(walletAddress).isValidSignature.selector,
            hash,
            signature
        );
        bytes32 magic_salt = bytes32(bytes4(keccak256("isValidWalletSignature(bytes32,address,bytes)")));
        assembly {
            if iszero(extcodesize(walletAddress)) {
                // Revert with `Error("WALLET_ERROR")`
                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
                mstore(64, 0x0000000c57414c4c45545f4552524f5200000000000000000000000000000000)
                mstore(96, 0)
                revert(0, 100)
            }

            let cdStart := add(calldata, 32)
            let success := staticcall(
                gas,              // forward all gas
                walletAddress,    // address of Wallet contract
                cdStart,          // pointer to start of input
                mload(calldata),  // length of input
                cdStart,          // write output over input
                32                // output size is 32 bytes
            )

            if iszero(eq(returndatasize(), 32)) {
                // Revert with `Error("WALLET_ERROR")`
                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
                mstore(64, 0x0000000c57414c4c45545f4552524f5200000000000000000000000000000000)
                mstore(96, 0)
                revert(0, 100)
            }

            switch success
            case 0 {
                // Revert with `Error("WALLET_ERROR")`
                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
                mstore(64, 0x0000000c57414c4c45545f4552524f5200000000000000000000000000000000)
                mstore(96, 0)
                revert(0, 100)
            }
            case 1 {
                // Signature is valid if call did not revert and returned true
                isValid := eq(
                    and(mload(cdStart), 0xffffffff00000000000000000000000000000000000000000000000000000000),
                    and(magic_salt, 0xffffffff00000000000000000000000000000000000000000000000000000000)
                )
            }
        }
        return isValid;
    }

    /// @dev Verifies signature using logic defined by Validator contract.
    /// @param validatorAddress Address of validator contract.
    /// @param hash Any 32 byte hash.
    /// @param signerAddress Address that should have signed the given hash.
    /// @param signature Proof that the hash has been signed by signer.
    /// @return True if the address recovered from the provided signature matches the input signer address.
    function isValidValidatorSignature(
        address validatorAddress,
        bytes32 hash,
        address signerAddress,
        bytes signature
    )
        internal
        view
        returns (bool isValid)
    {
        bytes memory calldata = abi.encodeWithSelector(
            IValidator(signerAddress).isValidSignature.selector,
            hash,
            signerAddress,
            signature
        );
        bytes32 magic_salt = bytes32(bytes4(keccak256("isValidValidatorSignature(address,bytes32,address,bytes)")));
        assembly {
            if iszero(extcodesize(validatorAddress)) {
                // Revert with `Error("VALIDATOR_ERROR")`
                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
                mstore(64, 0x0000000f56414c494441544f525f4552524f5200000000000000000000000000)
                mstore(96, 0)
                revert(0, 100)
            }

            let cdStart := add(calldata, 32)
            let success := staticcall(
                gas,               // forward all gas
                validatorAddress,  // address of Validator contract
                cdStart,           // pointer to start of input
                mload(calldata),   // length of input
                cdStart,           // write output over input
                32                 // output size is 32 bytes
            )

            if iszero(eq(returndatasize(), 32)) {
                // Revert with `Error("VALIDATOR_ERROR")`
                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
                mstore(64, 0x0000000f56414c494441544f525f4552524f5200000000000000000000000000)
                mstore(96, 0)
                revert(0, 100)
            }

            switch success
            case 0 {
                // Revert with `Error("VALIDATOR_ERROR")`
                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
                mstore(64, 0x0000000f56414c494441544f525f4552524f5200000000000000000000000000)
                mstore(96, 0)
                revert(0, 100)
            }
            case 1 {
                // Signature is valid if call did not revert and returned true
                isValid := eq(
                    and(mload(cdStart), 0xffffffff00000000000000000000000000000000000000000000000000000000),
                    and(magic_salt, 0xffffffff00000000000000000000000000000000000000000000000000000000)
                )
            }
        }
        return isValid;
    }
}

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;





/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;




contract LibAbiEncoder {

    /// @dev ABI encodes calldata for `fillOrder`.
    /// @param order Order struct containing order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signature Proof that order has been created by maker.
    /// @return ABI encoded calldata for `fillOrder`.
    function abiEncodeFillOrder(
        LibOrder.Order memory order,
        uint256 takerAssetFillAmount,
        bytes memory signature
    )
        internal
        pure
        returns (bytes memory fillOrderCalldata)
    {
        // We need to call MExchangeCore.fillOrder using a delegatecall in
        // assembly so that we can intercept a call that throws. For this, we
        // need the input encoded in memory in the Ethereum ABIv2 format [1].

        // | Area     | Offset | Length  | Contents                                    |
        // | -------- |--------|---------|-------------------------------------------- |
        // | Header   | 0x00   | 4       | function selector                           |
        // | Params   |        | 3 * 32  | function parameters:                        |
        // |          | 0x00   |         |   1. offset to order (*)                    |
        // |          | 0x20   |         |   2. takerAssetFillAmount                   |
        // |          | 0x40   |         |   3. offset to signature (*)                |
        // | Data     |        | 12 * 32 | order:                                      |
        // |          | 0x000  |         |   1.  senderAddress                         |
        // |          | 0x020  |         |   2.  makerAddress                          |
        // |          | 0x040  |         |   3.  takerAddress                          |
        // |          | 0x060  |         |   4.  feeRecipientAddress                   |
        // |          | 0x080  |         |   5.  makerAssetAmount                      |
        // |          | 0x0A0  |         |   6.  takerAssetAmount                      |
        // |          | 0x0C0  |         |   7.  makerFeeAmount                        |
        // |          | 0x0E0  |         |   8.  takerFeeAmount                        |
        // |          | 0x100  |         |   9.  expirationTimeSeconds                 |
        // |          | 0x120  |         |   10. salt                                  |
        // |          | 0x140  |         |   11. Offset to makerAssetData (*)          |
        // |          | 0x160  |         |   12. Offset to takerAssetData (*)          |
        // |          | 0x180  | 32      | makerAssetData Length                       |
        // |          | 0x1A0  | **      | makerAssetData Contents                     |
        // |          | 0x1C0  | 32      | takerAssetData Length                       |
        // |          | 0x1E0  | **      | takerAssetData Contents                     |
        // |          | 0x200  | 32      | signature Length                            |
        // |          | 0x220  | **      | signature Contents                          |

        // * Offsets are calculated from the beginning of the current area: Header, Params, Data:
        //     An offset stored in the Params area is calculated from the beginning of the Params section.
        //     An offset stored in the Data area is calculated from the beginning of the Data section.

        // ** The length of dynamic array contents are stored in the field immediately preceeding the contents.

        // [1]: https://solidity.readthedocs.io/en/develop/abi-spec.html

        assembly {

            // Areas below may use the following variables:
            //   1. <area>Start   -- Start of this area in memory
            //   2. <area>End     -- End of this area in memory. This value may
            //                       be precomputed (before writing contents),
            //                       or it may be computed as contents are written.
            //   3. <area>Offset  -- Current offset into area. If an area's End
            //                       is precomputed, this variable tracks the
            //                       offsets of contents as they are written.

            /////// Setup Header Area ///////
            // Load free memory pointer
            fillOrderCalldata := mload(0x40)
            // bytes4(keccak256("fillOrder((address,address,address,address,uint256,uint256,uint256,uint256,uint256,uint256,bytes,bytes),uint256,bytes)"))
            // = 0xb4be83d5
            // Leave 0x20 bytes to store the length
            mstore(add(fillOrderCalldata, 0x20), 0xb4be83d500000000000000000000000000000000000000000000000000000000)
            let headerAreaEnd := add(fillOrderCalldata, 0x24)

            /////// Setup Params Area ///////
            // This area is preallocated and written to later.
            // This is because we need to fill in offsets that have not yet been calculated.
            let paramsAreaStart := headerAreaEnd
            let paramsAreaEnd := add(paramsAreaStart, 0x60)
            let paramsAreaOffset := paramsAreaStart

            /////// Setup Data Area ///////
            let dataAreaStart := paramsAreaEnd
            let dataAreaEnd := dataAreaStart

            // Offset from the source data we're reading from
            let sourceOffset := order
            // arrayLenBytes and arrayLenWords track the length of a dynamically-allocated bytes array.
            let arrayLenBytes := 0
            let arrayLenWords := 0

            /////// Write order Struct ///////
            // Write memory location of Order, relative to the start of the
            // parameter list, then increment the paramsAreaOffset respectively.
            mstore(paramsAreaOffset, sub(dataAreaEnd, paramsAreaStart))
            paramsAreaOffset := add(paramsAreaOffset, 0x20)

            // Write values for each field in the order
            // It would be nice to use a loop, but we save on gas by writing
            // the stores sequentially.
            mstore(dataAreaEnd, mload(sourceOffset))                            // makerAddress
            mstore(add(dataAreaEnd, 0x20), mload(add(sourceOffset, 0x20)))      // takerAddress
            mstore(add(dataAreaEnd, 0x40), mload(add(sourceOffset, 0x40)))      // feeRecipientAddress
            mstore(add(dataAreaEnd, 0x60), mload(add(sourceOffset, 0x60)))      // senderAddress
            mstore(add(dataAreaEnd, 0x80), mload(add(sourceOffset, 0x80)))      // makerAssetAmount
            mstore(add(dataAreaEnd, 0xA0), mload(add(sourceOffset, 0xA0)))      // takerAssetAmount
            mstore(add(dataAreaEnd, 0xC0), mload(add(sourceOffset, 0xC0)))      // makerFeeAmount
            mstore(add(dataAreaEnd, 0xE0), mload(add(sourceOffset, 0xE0)))      // takerFeeAmount
            mstore(add(dataAreaEnd, 0x100), mload(add(sourceOffset, 0x100)))    // expirationTimeSeconds
            mstore(add(dataAreaEnd, 0x120), mload(add(sourceOffset, 0x120)))    // salt
            mstore(add(dataAreaEnd, 0x140), mload(add(sourceOffset, 0x140)))    // Offset to makerAssetData
            mstore(add(dataAreaEnd, 0x160), mload(add(sourceOffset, 0x160)))    // Offset to takerAssetData
            dataAreaEnd := add(dataAreaEnd, 0x180)
            sourceOffset := add(sourceOffset, 0x180)

            // Write offset to <order.makerAssetData>
            mstore(add(dataAreaStart, mul(10, 0x20)), sub(dataAreaEnd, dataAreaStart))

            // Calculate length of <order.makerAssetData>
            sourceOffset := mload(add(order, 0x140)) // makerAssetData
            arrayLenBytes := mload(sourceOffset)
            sourceOffset := add(sourceOffset, 0x20)
            arrayLenWords := div(add(arrayLenBytes, 0x1F), 0x20)

            // Write length of <order.makerAssetData>
            mstore(dataAreaEnd, arrayLenBytes)
            dataAreaEnd := add(dataAreaEnd, 0x20)

            // Write contents of <order.makerAssetData>
            for {let i := 0} lt(i, arrayLenWords) {i := add(i, 1)} {
                mstore(dataAreaEnd, mload(sourceOffset))
                dataAreaEnd := add(dataAreaEnd, 0x20)
                sourceOffset := add(sourceOffset, 0x20)
            }

            // Write offset to <order.takerAssetData>
            mstore(add(dataAreaStart, mul(11, 0x20)), sub(dataAreaEnd, dataAreaStart))

            // Calculate length of <order.takerAssetData>
            sourceOffset := mload(add(order, 0x160)) // takerAssetData
            arrayLenBytes := mload(sourceOffset)
            sourceOffset := add(sourceOffset, 0x20)
            arrayLenWords := div(add(arrayLenBytes, 0x1F), 0x20)

            // Write length of <order.takerAssetData>
            mstore(dataAreaEnd, arrayLenBytes)
            dataAreaEnd := add(dataAreaEnd, 0x20)

            // Write contents of  <order.takerAssetData>
            for {let i := 0} lt(i, arrayLenWords) {i := add(i, 1)} {
                mstore(dataAreaEnd, mload(sourceOffset))
                dataAreaEnd := add(dataAreaEnd, 0x20)
                sourceOffset := add(sourceOffset, 0x20)
            }

            /////// Write takerAssetFillAmount ///////
            mstore(paramsAreaOffset, takerAssetFillAmount)
            paramsAreaOffset := add(paramsAreaOffset, 0x20)

            /////// Write signature ///////
            // Write offset to paramsArea
            mstore(paramsAreaOffset, sub(dataAreaEnd, paramsAreaStart))

            // Calculate length of signature
            sourceOffset := signature
            arrayLenBytes := mload(sourceOffset)
            sourceOffset := add(sourceOffset, 0x20)
            arrayLenWords := div(add(arrayLenBytes, 0x1F), 0x20)

            // Write length of signature
            mstore(dataAreaEnd, arrayLenBytes)
            dataAreaEnd := add(dataAreaEnd, 0x20)

            // Write contents of signature
            for {let i := 0} lt(i, arrayLenWords) {i := add(i, 1)} {
                mstore(dataAreaEnd, mload(sourceOffset))
                dataAreaEnd := add(dataAreaEnd, 0x20)
                sourceOffset := add(sourceOffset, 0x20)
            }

            // Set length of calldata
            mstore(fillOrderCalldata, sub(dataAreaEnd, add(fillOrderCalldata, 0x20)))

            // Increment free memory pointer
            mstore(0x40, dataAreaEnd)
        }

        return fillOrderCalldata;
    }
}


/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;



/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;





contract IWrapperFunctions {

    /// @dev Fills the input order. Reverts if exact takerAssetFillAmount not filled.
    /// @param order LibOrder.Order struct containing order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signature Proof that order has been created by maker.
    function fillOrKillOrder(
        LibOrder.Order memory order,
        uint256 takerAssetFillAmount,
        bytes memory signature
    )
        public
        returns (LibFillResults.FillResults memory fillResults);

    /// @dev Fills an order with specified parameters and ECDSA signature.
    ///      Returns false if the transaction would otherwise revert.
    /// @param order LibOrder.Order struct containing order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signature Proof that order has been created by maker.
    /// @return Amounts filled and fees paid by maker and taker.
    function fillOrderNoThrow(
        LibOrder.Order memory order,
        uint256 takerAssetFillAmount,
        bytes memory signature
    )
        public
        returns (LibFillResults.FillResults memory fillResults);

    /// @dev Synchronously executes multiple calls of fillOrder.
    /// @param orders Array of order specifications.
    /// @param takerAssetFillAmounts Array of desired amounts of takerAsset to sell in orders.
    /// @param signatures Proofs that orders have been created by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    function batchFillOrders(
        LibOrder.Order[] memory orders,
        uint256[] memory takerAssetFillAmounts,
        bytes[] memory signatures
    )
        public
        returns (LibFillResults.FillResults memory totalFillResults);

    /// @dev Synchronously executes multiple calls of fillOrKill.
    /// @param orders Array of order specifications.
    /// @param takerAssetFillAmounts Array of desired amounts of takerAsset to sell in orders.
    /// @param signatures Proofs that orders have been created by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    function batchFillOrKillOrders(
        LibOrder.Order[] memory orders,
        uint256[] memory takerAssetFillAmounts,
        bytes[] memory signatures
    )
        public
        returns (LibFillResults.FillResults memory totalFillResults);

    /// @dev Fills an order with specified parameters and ECDSA signature.
    ///      Returns false if the transaction would otherwise revert.
    /// @param orders Array of order specifications.
    /// @param takerAssetFillAmounts Array of desired amounts of takerAsset to sell in orders.
    /// @param signatures Proofs that orders have been created by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    function batchFillOrdersNoThrow(
        LibOrder.Order[] memory orders,
        uint256[] memory takerAssetFillAmounts,
        bytes[] memory signatures
    )
        public
        returns (LibFillResults.FillResults memory totalFillResults);

    /// @dev Synchronously executes multiple calls of fillOrder until total amount of takerAsset is sold by taker.
    /// @param orders Array of order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signatures Proofs that orders have been created by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    function marketSellOrders(
        LibOrder.Order[] memory orders,
        uint256 takerAssetFillAmount,
        bytes[] memory signatures
    )
        public
        returns (LibFillResults.FillResults memory totalFillResults);

    /// @dev Synchronously executes multiple calls of fillOrder until total amount of takerAsset is sold by taker.
    ///      Returns false if the transaction would otherwise revert.
    /// @param orders Array of order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signatures Proofs that orders have been signed by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    function marketSellOrdersNoThrow(
        LibOrder.Order[] memory orders,
        uint256 takerAssetFillAmount,
        bytes[] memory signatures
    )
        public
        returns (LibFillResults.FillResults memory totalFillResults);

    /// @dev Synchronously executes multiple calls of fillOrder until total amount of makerAsset is bought by taker.
    /// @param orders Array of order specifications.
    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
    /// @param signatures Proofs that orders have been signed by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    function marketBuyOrders(
        LibOrder.Order[] memory orders,
        uint256 makerAssetFillAmount,
        bytes[] memory signatures
    )
        public
        returns (LibFillResults.FillResults memory totalFillResults);

    /// @dev Synchronously executes multiple fill orders in a single transaction until total amount is bought by taker.
    ///      Returns false if the transaction would otherwise revert.
    /// @param orders Array of order specifications.
    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
    /// @param signatures Proofs that orders have been signed by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    function marketBuyOrdersNoThrow(
        LibOrder.Order[] memory orders,
        uint256 makerAssetFillAmount,
        bytes[] memory signatures
    )
        public
        returns (LibFillResults.FillResults memory totalFillResults);

    /// @dev Synchronously cancels multiple orders in a single transaction.
    /// @param orders Array of order specifications.
    function batchCancelOrders(LibOrder.Order[] memory orders)
        public;

    /// @dev Fetches information for all passed in orders
    /// @param orders Array of order specifications.
    /// @return Array of OrderInfo instances that correspond to each order.
    function getOrdersInfo(LibOrder.Order[] memory orders)
        public
        view
        returns (LibOrder.OrderInfo[] memory);
}



contract MWrapperFunctions is 
    IWrapperFunctions
{
    /// @dev Fills the input order. Reverts if exact takerAssetFillAmount not filled.
    /// @param order LibOrder.Order struct containing order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signature Proof that order has been created by maker.
    function fillOrKillOrderInternal(
        LibOrder.Order memory order,
        uint256 takerAssetFillAmount,
        bytes memory signature
    )
        internal
        returns (LibFillResults.FillResults memory fillResults);
}



contract MixinWrapperFunctions is
    ReentrancyGuard,
    LibMath,
    LibFillResults,
    LibAbiEncoder,
    MExchangeCore,
    MWrapperFunctions
{
    /// @dev Fills the input order. Reverts if exact takerAssetFillAmount not filled.
    /// @param order Order struct containing order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signature Proof that order has been created by maker.
    function fillOrKillOrder(
        LibOrder.Order memory order,
        uint256 takerAssetFillAmount,
        bytes memory signature
    )
        public
        nonReentrant
        returns (FillResults memory fillResults)
    {
        fillResults = fillOrKillOrderInternal(
            order,
            takerAssetFillAmount,
            signature
        );
        return fillResults;
    }

    /// @dev Fills the input order.
    ///      Returns false if the transaction would otherwise revert.
    /// @param order Order struct containing order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signature Proof that order has been created by maker.
    /// @return Amounts filled and fees paid by maker and taker.
    function fillOrderNoThrow(
        LibOrder.Order memory order,
        uint256 takerAssetFillAmount,
        bytes memory signature
    )
        public
        returns (FillResults memory fillResults)
    {
        // ABI encode calldata for `fillOrder`
        bytes memory fillOrderCalldata = abiEncodeFillOrder(
            order,
            takerAssetFillAmount,
            signature
        );

        // Delegate to `fillOrder` and handle any exceptions gracefully
        assembly {
            let success := delegatecall(
                gas,                                // forward all gas
                address,                            // call address of this contract
                add(fillOrderCalldata, 32),         // pointer to start of input (skip array length in first 32 bytes)
                mload(fillOrderCalldata),           // length of input
                fillOrderCalldata,                  // write output over input
                128                                 // output size is 128 bytes
            )
            if success {
                mstore(fillResults, mload(fillOrderCalldata))
                mstore(add(fillResults, 32), mload(add(fillOrderCalldata, 32)))
                mstore(add(fillResults, 64), mload(add(fillOrderCalldata, 64)))
                mstore(add(fillResults, 96), mload(add(fillOrderCalldata, 96)))
            }
        }
        // fillResults values will be 0 by default if call was unsuccessful
        return fillResults;
    }

    /// @dev Synchronously executes multiple calls of fillOrder.
    /// @param orders Array of order specifications.
    /// @param takerAssetFillAmounts Array of desired amounts of takerAsset to sell in orders.
    /// @param signatures Proofs that orders have been created by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    ///         NOTE: makerAssetFilledAmount and takerAssetFilledAmount may include amounts filled of different assets.
    function batchFillOrders(
        LibOrder.Order[] memory orders,
        uint256[] memory takerAssetFillAmounts,
        bytes[] memory signatures
    )
        public
        nonReentrant
        returns (FillResults memory totalFillResults)
    {
        uint256 ordersLength = orders.length;
        for (uint256 i = 0; i != ordersLength; i++) {
            FillResults memory singleFillResults = fillOrderInternal(
                orders[i],
                takerAssetFillAmounts[i],
                signatures[i]
            );
            addFillResults(totalFillResults, singleFillResults);
        }
        return totalFillResults;
    }

    /// @dev Synchronously executes multiple calls of fillOrKill.
    /// @param orders Array of order specifications.
    /// @param takerAssetFillAmounts Array of desired amounts of takerAsset to sell in orders.
    /// @param signatures Proofs that orders have been created by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    ///         NOTE: makerAssetFilledAmount and takerAssetFilledAmount may include amounts filled of different assets.
    function batchFillOrKillOrders(
        LibOrder.Order[] memory orders,
        uint256[] memory takerAssetFillAmounts,
        bytes[] memory signatures
    )
        public
        nonReentrant
        returns (FillResults memory totalFillResults)
    {
        uint256 ordersLength = orders.length;
        for (uint256 i = 0; i != ordersLength; i++) {
            FillResults memory singleFillResults = fillOrKillOrderInternal(
                orders[i],
                takerAssetFillAmounts[i],
                signatures[i]
            );
            addFillResults(totalFillResults, singleFillResults);
        }
        return totalFillResults;
    }

    /// @dev Fills an order with specified parameters and ECDSA signature.
    ///      Returns false if the transaction would otherwise revert.
    /// @param orders Array of order specifications.
    /// @param takerAssetFillAmounts Array of desired amounts of takerAsset to sell in orders.
    /// @param signatures Proofs that orders have been created by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    ///         NOTE: makerAssetFilledAmount and takerAssetFilledAmount may include amounts filled of different assets.
    function batchFillOrdersNoThrow(
        LibOrder.Order[] memory orders,
        uint256[] memory takerAssetFillAmounts,
        bytes[] memory signatures
    )
        public
        returns (FillResults memory totalFillResults)
    {
        uint256 ordersLength = orders.length;
        for (uint256 i = 0; i != ordersLength; i++) {
            FillResults memory singleFillResults = fillOrderNoThrow(
                orders[i],
                takerAssetFillAmounts[i],
                signatures[i]
            );
            addFillResults(totalFillResults, singleFillResults);
        }
        return totalFillResults;
    }

    /// @dev Synchronously executes multiple calls of fillOrder until total amount of takerAsset is sold by taker.
    /// @param orders Array of order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signatures Proofs that orders have been created by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    function marketSellOrders(
        LibOrder.Order[] memory orders,
        uint256 takerAssetFillAmount,
        bytes[] memory signatures
    )
        public
        nonReentrant
        returns (FillResults memory totalFillResults)
    {
        bytes memory takerAssetData = orders[0].takerAssetData;
    
        uint256 ordersLength = orders.length;
        for (uint256 i = 0; i != ordersLength; i++) {

            // We assume that asset being sold by taker is the same for each order.
            // Rather than passing this in as calldata, we use the takerAssetData from the first order in all later orders.
            orders[i].takerAssetData = takerAssetData;

            // Calculate the remaining amount of takerAsset to sell
            uint256 remainingTakerAssetFillAmount = safeSub(takerAssetFillAmount, totalFillResults.takerAssetFilledAmount);

            // Attempt to sell the remaining amount of takerAsset
            FillResults memory singleFillResults = fillOrderInternal(
                orders[i],
                remainingTakerAssetFillAmount,
                signatures[i]
            );

            // Update amounts filled and fees paid by maker and taker
            addFillResults(totalFillResults, singleFillResults);

            // Stop execution if the entire amount of takerAsset has been sold
            if (totalFillResults.takerAssetFilledAmount >= takerAssetFillAmount) {
                break;
            }
        }
        return totalFillResults;
    }

    /// @dev Synchronously executes multiple calls of fillOrder until total amount of takerAsset is sold by taker.
    ///      Returns false if the transaction would otherwise revert.
    /// @param orders Array of order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signatures Proofs that orders have been signed by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    function marketSellOrdersNoThrow(
        LibOrder.Order[] memory orders,
        uint256 takerAssetFillAmount,
        bytes[] memory signatures
    )
        public
        returns (FillResults memory totalFillResults)
    {
        bytes memory takerAssetData = orders[0].takerAssetData;

        uint256 ordersLength = orders.length;
        for (uint256 i = 0; i != ordersLength; i++) {

            // We assume that asset being sold by taker is the same for each order.
            // Rather than passing this in as calldata, we use the takerAssetData from the first order in all later orders.
            orders[i].takerAssetData = takerAssetData;

            // Calculate the remaining amount of takerAsset to sell
            uint256 remainingTakerAssetFillAmount = safeSub(takerAssetFillAmount, totalFillResults.takerAssetFilledAmount);

            // Attempt to sell the remaining amount of takerAsset
            FillResults memory singleFillResults = fillOrderNoThrow(
                orders[i],
                remainingTakerAssetFillAmount,
                signatures[i]
            );

            // Update amounts filled and fees paid by maker and taker
            addFillResults(totalFillResults, singleFillResults);

            // Stop execution if the entire amount of takerAsset has been sold
            if (totalFillResults.takerAssetFilledAmount >= takerAssetFillAmount) {
                break;
            }
        }
        return totalFillResults;
    }

    /// @dev Synchronously executes multiple calls of fillOrder until total amount of makerAsset is bought by taker.
    /// @param orders Array of order specifications.
    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
    /// @param signatures Proofs that orders have been signed by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    function marketBuyOrders(
        LibOrder.Order[] memory orders,
        uint256 makerAssetFillAmount,
        bytes[] memory signatures
    )
        public
        nonReentrant
        returns (FillResults memory totalFillResults)
    {
        bytes memory makerAssetData = orders[0].makerAssetData;

        uint256 ordersLength = orders.length;
        for (uint256 i = 0; i != ordersLength; i++) {

            // We assume that asset being bought by taker is the same for each order.
            // Rather than passing this in as calldata, we copy the makerAssetData from the first order onto all later orders.
            orders[i].makerAssetData = makerAssetData;

            // Calculate the remaining amount of makerAsset to buy
            uint256 remainingMakerAssetFillAmount = safeSub(makerAssetFillAmount, totalFillResults.makerAssetFilledAmount);

            // Convert the remaining amount of makerAsset to buy into remaining amount
            // of takerAsset to sell, assuming entire amount can be sold in the current order
            uint256 remainingTakerAssetFillAmount = getPartialAmountFloor(
                orders[i].takerAssetAmount,
                orders[i].makerAssetAmount,
                remainingMakerAssetFillAmount
            );

            // Attempt to sell the remaining amount of takerAsset
            FillResults memory singleFillResults = fillOrderInternal(
                orders[i],
                remainingTakerAssetFillAmount,
                signatures[i]
            );

            // Update amounts filled and fees paid by maker and taker
            addFillResults(totalFillResults, singleFillResults);

            // Stop execution if the entire amount of makerAsset has been bought
            if (totalFillResults.makerAssetFilledAmount >= makerAssetFillAmount) {
                break;
            }
        }
        return totalFillResults;
    }

    /// @dev Synchronously executes multiple fill orders in a single transaction until total amount is bought by taker.
    ///      Returns false if the transaction would otherwise revert.
    /// @param orders Array of order specifications.
    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
    /// @param signatures Proofs that orders have been signed by makers.
    /// @return Amounts filled and fees paid by makers and taker.
    function marketBuyOrdersNoThrow(
        LibOrder.Order[] memory orders,
        uint256 makerAssetFillAmount,
        bytes[] memory signatures
    )
        public
        returns (FillResults memory totalFillResults)
    {
        bytes memory makerAssetData = orders[0].makerAssetData;

        uint256 ordersLength = orders.length;
        for (uint256 i = 0; i != ordersLength; i++) {

            // We assume that asset being bought by taker is the same for each order.
            // Rather than passing this in as calldata, we copy the makerAssetData from the first order onto all later orders.
            orders[i].makerAssetData = makerAssetData;

            // Calculate the remaining amount of makerAsset to buy
            uint256 remainingMakerAssetFillAmount = safeSub(makerAssetFillAmount, totalFillResults.makerAssetFilledAmount);

            // Convert the remaining amount of makerAsset to buy into remaining amount
            // of takerAsset to sell, assuming entire amount can be sold in the current order
            uint256 remainingTakerAssetFillAmount = getPartialAmountFloor(
                orders[i].takerAssetAmount,
                orders[i].makerAssetAmount,
                remainingMakerAssetFillAmount
            );

            // Attempt to sell the remaining amount of takerAsset
            FillResults memory singleFillResults = fillOrderNoThrow(
                orders[i],
                remainingTakerAssetFillAmount,
                signatures[i]
            );

            // Update amounts filled and fees paid by maker and taker
            addFillResults(totalFillResults, singleFillResults);

            // Stop execution if the entire amount of makerAsset has been bought
            if (totalFillResults.makerAssetFilledAmount >= makerAssetFillAmount) {
                break;
            }
        }
        return totalFillResults;
    }

    /// @dev Synchronously cancels multiple orders in a single transaction.
    /// @param orders Array of order specifications.
    function batchCancelOrders(LibOrder.Order[] memory orders)
        public
        nonReentrant
    {
        uint256 ordersLength = orders.length;
        for (uint256 i = 0; i != ordersLength; i++) {
            cancelOrderInternal(orders[i]);
        }
    }

    /// @dev Fetches information for all passed in orders.
    /// @param orders Array of order specifications.
    /// @return Array of OrderInfo instances that correspond to each order.
    function getOrdersInfo(LibOrder.Order[] memory orders)
        public
        view
        returns (LibOrder.OrderInfo[] memory)
    {
        uint256 ordersLength = orders.length;
        LibOrder.OrderInfo[] memory ordersInfo = new LibOrder.OrderInfo[](ordersLength);
        for (uint256 i = 0; i != ordersLength; i++) {
            ordersInfo[i] = getOrderInfo(orders[i]);
        }
        return ordersInfo;
    }

    /// @dev Fills the input order. Reverts if exact takerAssetFillAmount not filled.
    /// @param order Order struct containing order specifications.
    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
    /// @param signature Proof that order has been created by maker.
    function fillOrKillOrderInternal(
        LibOrder.Order memory order,
        uint256 takerAssetFillAmount,
        bytes memory signature
    )
        internal
        returns (FillResults memory fillResults)
    {
        fillResults = fillOrderInternal(
            order,
            takerAssetFillAmount,
            signature
        );
        require(
            fillResults.takerAssetFilledAmount == takerAssetFillAmount,
            "COMPLETE_FILL_FAILED"
        );
        return fillResults;
    }
}

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;

pragma solidity 0.4.24;

pragma solidity 0.4.24;


contract IOwnable {

    function transferOwnership(address newOwner)
        public;
}



contract Ownable is
    IOwnable
{
    address public owner;

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

    modifier onlyOwner() {
        require(
            msg.sender == owner,
            "ONLY_CONTRACT_OWNER"
        );
        _;
    }

    function transferOwnership(address newOwner)
        public
        onlyOwner
    {
        if (newOwner != address(0)) {
            owner = newOwner;
        }
    }
}


/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;




contract IAuthorizable is
    IOwnable
{
    /// @dev Authorizes an address.
    /// @param target Address to authorize.
    function addAuthorizedAddress(address target)
        external;

    /// @dev Removes authorizion of an address.
    /// @param target Address to remove authorization from.
    function removeAuthorizedAddress(address target)
        external;

    /// @dev Removes authorizion of an address.
    /// @param target Address to remove authorization from.
    /// @param index Index of target in authorities array.
    function removeAuthorizedAddressAtIndex(
        address target,
        uint256 index
    )
        external;
    
    /// @dev Gets all authorized addresses.
    /// @return Array of authorized addresses.
    function getAuthorizedAddresses()
        external
        view
        returns (address[] memory);
}



contract IAssetProxy is
    IAuthorizable
{
    /// @dev Transfers assets. Either succeeds or throws.
    /// @param assetData Byte array encoded for the respective asset proxy.
    /// @param from Address to transfer asset from.
    /// @param to Address to transfer asset to.
    /// @param amount Amount of asset to transfer.
    function transferFrom(
        bytes assetData,
        address from,
        address to,
        uint256 amount
    )
        external;
    
    /// @dev Gets the proxy id associated with the proxy address.
    /// @return Proxy id.
    function getProxyId()
        external
        pure
        returns (bytes4);
}



contract MixinAssetProxyDispatcher is
    Ownable,
    MAssetProxyDispatcher
{
    // Mapping from Asset Proxy Id's to their respective Asset Proxy
    mapping (bytes4 => IAssetProxy) public assetProxies;

    /// @dev Registers an asset proxy to its asset proxy id.
    ///      Once an asset proxy is registered, it cannot be unregistered.
    /// @param assetProxy Address of new asset proxy to register.
    function registerAssetProxy(address assetProxy)
        external
        onlyOwner
    {
        IAssetProxy assetProxyContract = IAssetProxy(assetProxy);

        // Ensure that no asset proxy exists with current id.
        bytes4 assetProxyId = assetProxyContract.getProxyId();
        address currentAssetProxy = assetProxies[assetProxyId];
        require(
            currentAssetProxy == address(0),
            "ASSET_PROXY_ALREADY_EXISTS"
        );

        // Add asset proxy and log registration.
        assetProxies[assetProxyId] = assetProxyContract;
        emit AssetProxyRegistered(
            assetProxyId,
            assetProxy
        );
    }

    /// @dev Gets an asset proxy.
    /// @param assetProxyId Id of the asset proxy.
    /// @return The asset proxy registered to assetProxyId. Returns 0x0 if no proxy is registered.
    function getAssetProxy(bytes4 assetProxyId)
        external
        view
        returns (address)
    {
        return assetProxies[assetProxyId];
    }

    /// @dev Forwards arguments to assetProxy and calls `transferFrom`. Either succeeds or throws.
    /// @param assetData Byte array encoded for the asset.
    /// @param from Address to transfer token from.
    /// @param to Address to transfer token to.
    /// @param amount Amount of token to transfer.
    function dispatchTransferFrom(
        bytes memory assetData,
        address from,
        address to,
        uint256 amount
    )
        internal
    {
        // Do nothing if no amount should be transferred.
        if (amount > 0 && from != to) {
            // Ensure assetData length is valid
            require(
                assetData.length > 3,
                "LENGTH_GREATER_THAN_3_REQUIRED"
            );
            
            // Lookup assetProxy. We do not use `LibBytes.readBytes4` for gas efficiency reasons.
            bytes4 assetProxyId;
            assembly {
                assetProxyId := and(mload(
                    add(assetData, 32)),
                    0xFFFFFFFF00000000000000000000000000000000000000000000000000000000
                )
            }
            address assetProxy = assetProxies[assetProxyId];

            // Ensure that assetProxy exists
            require(
                assetProxy != address(0),
                "ASSET_PROXY_DOES_NOT_EXIST"
            );
            
            // We construct calldata for the `assetProxy.transferFrom` ABI.
            // The layout of this calldata is in the table below.
            // 
            // | Area     | Offset | Length  | Contents                                    |
            // | -------- |--------|---------|-------------------------------------------- |
            // | Header   | 0      | 4       | function selector                           |
            // | Params   |        | 4 * 32  | function parameters:                        |
            // |          | 4      |         |   1. offset to assetData (*)                |
            // |          | 36     |         |   2. from                                   |
            // |          | 68     |         |   3. to                                     |
            // |          | 100    |         |   4. amount                                 |
            // | Data     |        |         | assetData:                                  |
            // |          | 132    | 32      | assetData Length                            |
            // |          | 164    | **      | assetData Contents                          |

            assembly {
                /////// Setup State ///////
                // `cdStart` is the start of the calldata for `assetProxy.transferFrom` (equal to free memory ptr).
                let cdStart := mload(64)
                // `dataAreaLength` is the total number of words needed to store `assetData`
                //  As-per the ABI spec, this value is padded up to the nearest multiple of 32,
                //  and includes 32-bytes for length.
                let dataAreaLength := and(add(mload(assetData), 63), 0xFFFFFFFFFFFE0)
                // `cdEnd` is the end of the calldata for `assetProxy.transferFrom`.
                let cdEnd := add(cdStart, add(132, dataAreaLength))

                
                /////// Setup Header Area ///////
                // This area holds the 4-byte `transferFromSelector`.
                // bytes4(keccak256("transferFrom(bytes,address,address,uint256)")) = 0xa85e59e4
                mstore(cdStart, 0xa85e59e400000000000000000000000000000000000000000000000000000000)
                
                /////// Setup Params Area ///////
                // Each parameter is padded to 32-bytes. The entire Params Area is 128 bytes.
                // Notes:
                //   1. The offset to `assetData` is the length of the Params Area (128 bytes).
                //   2. A 20-byte mask is applied to addresses to zero-out the unused bytes.
                mstore(add(cdStart, 4), 128)
                mstore(add(cdStart, 36), and(from, 0xffffffffffffffffffffffffffffffffffffffff))
                mstore(add(cdStart, 68), and(to, 0xffffffffffffffffffffffffffffffffffffffff))
                mstore(add(cdStart, 100), amount)
                
                /////// Setup Data Area ///////
                // This area holds `assetData`.
                let dataArea := add(cdStart, 132)
                // solhint-disable-next-line no-empty-blocks
                for {} lt(dataArea, cdEnd) {} {
                    mstore(dataArea, mload(assetData))
                    dataArea := add(dataArea, 32)
                    assetData := add(assetData, 32)
                }

                /////// Call `assetProxy.transferFrom` using the constructed calldata ///////
                let success := call(
                    gas,                    // forward all gas
                    assetProxy,             // call address of asset proxy
                    0,                      // don't send any ETH
                    cdStart,                // pointer to start of input
                    sub(cdEnd, cdStart),    // length of input  
                    cdStart,                // write output over input
                    512                     // reserve 512 bytes for output
                )
                if iszero(success) {
                    revert(cdStart, returndatasize())
                }
            }
        }
    }
}

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/
pragma solidity 0.4.24;

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

// solhint-disable
pragma solidity 0.4.24;


/// @dev This contract documents the revert reasons used in the Exchange contract.
/// This contract is intended to serve as a reference, but is not actually used for efficiency reasons.
contract LibExchangeErrors {

    /// Order validation errors ///
    string constant ORDER_UNFILLABLE = "ORDER_UNFILLABLE";                              // Order cannot be filled.
    string constant INVALID_MAKER = "INVALID_MAKER";                                    // Invalid makerAddress.
    string constant INVALID_TAKER = "INVALID_TAKER";                                    // Invalid takerAddress.
    string constant INVALID_SENDER = "INVALID_SENDER";                                  // Invalid `msg.sender`.
    string constant INVALID_ORDER_SIGNATURE = "INVALID_ORDER_SIGNATURE";                // Signature validation failed. 
    
    /// fillOrder validation errors ///
    string constant INVALID_TAKER_AMOUNT = "INVALID_TAKER_AMOUNT";                      // takerAssetFillAmount cannot equal 0.
    string constant ROUNDING_ERROR = "ROUNDING_ERROR";                                  // Rounding error greater than 0.1% of takerAssetFillAmount. 
    
    /// Signature validation errors ///
    string constant INVALID_SIGNATURE = "INVALID_SIGNATURE";                            // Signature validation failed. 
    string constant SIGNATURE_ILLEGAL = "SIGNATURE_ILLEGAL";                            // Signature type is illegal.
    string constant SIGNATURE_UNSUPPORTED = "SIGNATURE_UNSUPPORTED";                    // Signature type unsupported.
    
    /// cancelOrdersUptTo errors ///
    string constant INVALID_NEW_ORDER_EPOCH = "INVALID_NEW_ORDER_EPOCH";                // Specified salt must be greater than or equal to existing orderEpoch.

    /// fillOrKillOrder errors ///
    string constant COMPLETE_FILL_FAILED = "COMPLETE_FILL_FAILED";                      // Desired takerAssetFillAmount could not be completely filled. 

    /// matchOrders errors ///
    string constant NEGATIVE_SPREAD_REQUIRED = "NEGATIVE_SPREAD_REQUIRED";              // Matched orders must have a negative spread.

    /// Transaction errors ///
    string constant REENTRANCY_ILLEGAL = "REENTRANCY_ILLEGAL";                          // Recursive reentrancy is not allowed. 
    string constant INVALID_TX_HASH = "INVALID_TX_HASH";                                // Transaction has already been executed. 
    string constant INVALID_TX_SIGNATURE = "INVALID_TX_SIGNATURE";                      // Signature validation failed. 
    string constant FAILED_EXECUTION = "FAILED_EXECUTION";                              // Transaction execution failed. 
    
    /// registerAssetProxy errors ///
    string constant ASSET_PROXY_ALREADY_EXISTS = "ASSET_PROXY_ALREADY_EXISTS";          // AssetProxy with same id already exists.

    /// dispatchTransferFrom errors ///
    string constant ASSET_PROXY_DOES_NOT_EXIST = "ASSET_PROXY_DOES_NOT_EXIST";          // No assetProxy registered at given id.
    string constant TRANSFER_FAILED = "TRANSFER_FAILED";                                // Asset transfer unsuccesful.

    /// Length validation errors ///
    string constant LENGTH_GREATER_THAN_0_REQUIRED = "LENGTH_GREATER_THAN_0_REQUIRED";  // Byte array must have a length greater than 0.
    string constant LENGTH_GREATER_THAN_3_REQUIRED = "LENGTH_GREATER_THAN_3_REQUIRED";  // Byte array must have a length greater than 3.
    string constant LENGTH_0_REQUIRED = "LENGTH_0_REQUIRED";                            // Byte array must have a length of 0.
    string constant LENGTH_65_REQUIRED = "LENGTH_65_REQUIRED";                          // Byte array must have a length of 65.
}






contract MixinTransactions is
    LibEIP712,
    MSignatureValidator,
    MTransactions
{
    // Mapping of transaction hash => executed
    // This prevents transactions from being executed more than once.
    mapping (bytes32 => bool) public transactions;

    // Address of current transaction signer
    address public currentContextAddress;

    /// @dev Executes an exchange method call in the context of signer.
    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
    /// @param signerAddress Address of transaction signer.
    /// @param data AbiV2 encoded calldata.
    /// @param signature Proof of signer transaction by signer.
    function executeTransaction(
        uint256 salt,
        address signerAddress,
        bytes data,
        bytes signature
    )
        external
    {
        // Prevent reentrancy
        require(
            currentContextAddress == address(0),
            "REENTRANCY_ILLEGAL"
        );

        bytes32 transactionHash = hashEIP712Message(hashZeroExTransaction(
            salt,
            signerAddress,
            data
        ));

        // Validate transaction has not been executed
        require(
            !transactions[transactionHash],
            "INVALID_TX_HASH"
        );

        // Transaction always valid if signer is sender of transaction
        if (signerAddress != msg.sender) {
            // Validate signature
            require(
                isValidSignature(
                    transactionHash,
                    signerAddress,
                    signature
                ),
                "INVALID_TX_SIGNATURE"
            );

            // Set the current transaction signer
            currentContextAddress = signerAddress;
        }

        // Execute transaction
        transactions[transactionHash] = true;
        require(
            address(this).delegatecall(data),
            "FAILED_EXECUTION"
        );

        // Reset current transaction signer if it was previously updated
        if (signerAddress != msg.sender) {
            currentContextAddress = address(0);
        }
    }

    /// @dev Calculates EIP712 hash of the Transaction.
    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
    /// @param signerAddress Address of transaction signer.
    /// @param data AbiV2 encoded calldata.
    /// @return EIP712 hash of the Transaction.
    function hashZeroExTransaction(
        uint256 salt,
        address signerAddress,
        bytes memory data
    )
        internal
        pure
        returns (bytes32 result)
    {
        bytes32 schemaHash = EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH;
        bytes32 dataHash = keccak256(data);

        // Assembly for more efficiently computing:
        // keccak256(abi.encodePacked(
        //     EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH,
        //     salt,
        //     bytes32(signerAddress),
        //     keccak256(data)
        // ));

        assembly {
            // Load free memory pointer
            let memPtr := mload(64)

            mstore(memPtr, schemaHash)                                                               // hash of schema
            mstore(add(memPtr, 32), salt)                                                            // salt
            mstore(add(memPtr, 64), and(signerAddress, 0xffffffffffffffffffffffffffffffffffffffff))  // signerAddress
            mstore(add(memPtr, 96), dataHash)                                                        // hash of data

            // Compute hash
            result := keccak256(memPtr, 128)
        }
        return result;
    }

    /// @dev The current function will be called in the context of this address (either 0x transaction signer or `msg.sender`).
    ///      If calling a fill function, this address will represent the taker.
    ///      If calling a cancel function, this address will represent the maker.
    /// @return Signer of 0x transaction if entry point is `executeTransaction`.
    ///         `msg.sender` if entry point is any other function.
    function getCurrentContextAddress()
        internal
        view
        returns (address)
    {
        address currentContextAddress_ = currentContextAddress;
        address contextAddress = currentContextAddress_ == address(0) ? msg.sender : currentContextAddress_;
        return contextAddress;
    }
}

/*
  Copyright 2018 ZeroEx Intl.
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
    http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
*/

pragma solidity 0.4.24;







/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/
pragma solidity 0.4.24;



/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/
pragma solidity 0.4.24;





contract IMatchOrders {

    /// @dev Match two complementary orders that have a profitable spread.
    ///      Each order is filled at their respective price point. However, the calculations are
    ///      carried out as though the orders are both being filled at the right order's price point.
    ///      The profit made by the left order goes to the taker (who matched the two orders).
    /// @param leftOrder First order to match.
    /// @param rightOrder Second order to match.
    /// @param leftSignature Proof that order was created by the left maker.
    /// @param rightSignature Proof that order was created by the right maker.
    /// @return matchedFillResults Amounts filled and fees paid by maker and taker of matched orders.
    function matchOrders(
        LibOrder.Order memory leftOrder,
        LibOrder.Order memory rightOrder,
        bytes memory leftSignature,
        bytes memory rightSignature
    )
        public
        returns (LibFillResults.MatchedFillResults memory matchedFillResults);
}



contract MMatchOrders is
    IMatchOrders
{
    /// @dev Validates context for matchOrders. Succeeds or throws.
    /// @param leftOrder First order to match.
    /// @param rightOrder Second order to match.
    function assertValidMatch(
        LibOrder.Order memory leftOrder,
        LibOrder.Order memory rightOrder
    )
        internal
        pure;

    /// @dev Calculates fill amounts for the matched orders.
    ///      Each order is filled at their respective price point. However, the calculations are
    ///      carried out as though the orders are both being filled at the right order's price point.
    ///      The profit made by the leftOrder order goes to the taker (who matched the two orders).
    /// @param leftOrder First order to match.
    /// @param rightOrder Second order to match.
    /// @param leftOrderTakerAssetFilledAmount Amount of left order already filled.
    /// @param rightOrderTakerAssetFilledAmount Amount of right order already filled.
    /// @param matchedFillResults Amounts to fill and fees to pay by maker and taker of matched orders.
    function calculateMatchedFillResults(
        LibOrder.Order memory leftOrder,
        LibOrder.Order memory rightOrder,
        uint256 leftOrderTakerAssetFilledAmount,
        uint256 rightOrderTakerAssetFilledAmount
    )
        internal
        pure
        returns (LibFillResults.MatchedFillResults memory matchedFillResults);

}





contract MixinMatchOrders is
    ReentrancyGuard,
    LibConstants,
    LibMath,
    MAssetProxyDispatcher,
    MExchangeCore,
    MMatchOrders,
    MTransactions
{
    /// @dev Match two complementary orders that have a profitable spread.
    ///      Each order is filled at their respective price point. However, the calculations are
    ///      carried out as though the orders are both being filled at the right order's price point.
    ///      The profit made by the left order goes to the taker (who matched the two orders).
    /// @param leftOrder First order to match.
    /// @param rightOrder Second order to match.
    /// @param leftSignature Proof that order was created by the left maker.
    /// @param rightSignature Proof that order was created by the right maker.
    /// @return matchedFillResults Amounts filled and fees paid by maker and taker of matched orders.
    function matchOrders(
        LibOrder.Order memory leftOrder,
        LibOrder.Order memory rightOrder,
        bytes memory leftSignature,
        bytes memory rightSignature
    )
        public
        nonReentrant
        returns (LibFillResults.MatchedFillResults memory matchedFillResults)
    {
        // We assume that rightOrder.takerAssetData == leftOrder.makerAssetData and rightOrder.makerAssetData == leftOrder.takerAssetData.
        // If this assumption isn't true, the match will fail at signature validation.
        rightOrder.makerAssetData = leftOrder.takerAssetData;
        rightOrder.takerAssetData = leftOrder.makerAssetData;

        // Get left & right order info
        LibOrder.OrderInfo memory leftOrderInfo = getOrderInfo(leftOrder);
        LibOrder.OrderInfo memory rightOrderInfo = getOrderInfo(rightOrder);

        // Fetch taker address
        address takerAddress = getCurrentContextAddress();
        
        // Either our context is valid or we revert
        assertFillableOrder(
            leftOrder,
            leftOrderInfo,
            takerAddress,
            leftSignature
        );
        assertFillableOrder(
            rightOrder,
            rightOrderInfo,
            takerAddress,
            rightSignature
        );
        assertValidMatch(leftOrder, rightOrder);

        // Compute proportional fill amounts
        matchedFillResults = calculateMatchedFillResults(
            leftOrder,
            rightOrder,
            leftOrderInfo.orderTakerAssetFilledAmount,
            rightOrderInfo.orderTakerAssetFilledAmount
        );

        // Validate fill contexts
        assertValidFill(
            leftOrder,
            leftOrderInfo,
            matchedFillResults.left.takerAssetFilledAmount,
            matchedFillResults.left.takerAssetFilledAmount,
            matchedFillResults.left.makerAssetFilledAmount
        );
        assertValidFill(
            rightOrder,
            rightOrderInfo,
            matchedFillResults.right.takerAssetFilledAmount,
            matchedFillResults.right.takerAssetFilledAmount,
            matchedFillResults.right.makerAssetFilledAmount
        );
        
        // Update exchange state
        updateFilledState(
            leftOrder,
            takerAddress,
            leftOrderInfo.orderHash,
            leftOrderInfo.orderTakerAssetFilledAmount,
            matchedFillResults.left
        );
        updateFilledState(
            rightOrder,
            takerAddress,
            rightOrderInfo.orderHash,
            rightOrderInfo.orderTakerAssetFilledAmount,
            matchedFillResults.right
        );

        // Settle matched orders. Succeeds or throws.
        settleMatchedOrders(
            leftOrder,
            rightOrder,
            takerAddress,
            matchedFillResults
        );

        return matchedFillResults;
    }

    /// @dev Validates context for matchOrders. Succeeds or throws.
    /// @param leftOrder First order to match.
    /// @param rightOrder Second order to match.
    function assertValidMatch(
        LibOrder.Order memory leftOrder,
        LibOrder.Order memory rightOrder
    )
        internal
        pure
    {
        // Make sure there is a profitable spread.
        // There is a profitable spread iff the cost per unit bought (OrderA.MakerAmount/OrderA.TakerAmount) for each order is greater
        // than the profit per unit sold of the matched order (OrderB.TakerAmount/OrderB.MakerAmount).
        // This is satisfied by the equations below:
        // <leftOrder.makerAssetAmount> / <leftOrder.takerAssetAmount> >= <rightOrder.takerAssetAmount> / <rightOrder.makerAssetAmount>
        // AND
        // <rightOrder.makerAssetAmount> / <rightOrder.takerAssetAmount> >= <leftOrder.takerAssetAmount> / <leftOrder.makerAssetAmount>
        // These equations can be combined to get the following:
        require(
            safeMul(leftOrder.makerAssetAmount, rightOrder.makerAssetAmount) >=
            safeMul(leftOrder.takerAssetAmount, rightOrder.takerAssetAmount),
            "NEGATIVE_SPREAD_REQUIRED"
        );
    }

    /// @dev Calculates fill amounts for the matched orders.
    ///      Each order is filled at their respective price point. However, the calculations are
    ///      carried out as though the orders are both being filled at the right order's price point.
    ///      The profit made by the leftOrder order goes to the taker (who matched the two orders).
    /// @param leftOrder First order to match.
    /// @param rightOrder Second order to match.
    /// @param leftOrderTakerAssetFilledAmount Amount of left order already filled.
    /// @param rightOrderTakerAssetFilledAmount Amount of right order already filled.
    /// @param matchedFillResults Amounts to fill and fees to pay by maker and taker of matched orders.
    function calculateMatchedFillResults(
        LibOrder.Order memory leftOrder,
        LibOrder.Order memory rightOrder,
        uint256 leftOrderTakerAssetFilledAmount,
        uint256 rightOrderTakerAssetFilledAmount
    )
        internal
        pure
        returns (LibFillResults.MatchedFillResults memory matchedFillResults)
    {
        // Derive maker asset amounts for left & right orders, given store taker assert amounts
        uint256 leftTakerAssetAmountRemaining = safeSub(leftOrder.takerAssetAmount, leftOrderTakerAssetFilledAmount);
        uint256 leftMakerAssetAmountRemaining = safeGetPartialAmountFloor(
            leftOrder.makerAssetAmount,
            leftOrder.takerAssetAmount,
            leftTakerAssetAmountRemaining
        );
        uint256 rightTakerAssetAmountRemaining = safeSub(rightOrder.takerAssetAmount, rightOrderTakerAssetFilledAmount);
        uint256 rightMakerAssetAmountRemaining = safeGetPartialAmountFloor(
            rightOrder.makerAssetAmount,
            rightOrder.takerAssetAmount,
            rightTakerAssetAmountRemaining
        );

        // Calculate fill results for maker and taker assets: at least one order will be fully filled.
        // The maximum amount the left maker can buy is `leftTakerAssetAmountRemaining`
        // The maximum amount the right maker can sell is `rightMakerAssetAmountRemaining`
        // We have two distinct cases for calculating the fill results:
        // Case 1.
        //   If the left maker can buy more than the right maker can sell, then only the right order is fully filled.
        //   If the left maker can buy exactly what the right maker can sell, then both orders are fully filled.
        // Case 2.
        //   If the left maker cannot buy more than the right maker can sell, then only the left order is fully filled.
        if (leftTakerAssetAmountRemaining >= rightMakerAssetAmountRemaining) {
            // Case 1: Right order is fully filled
            matchedFillResults.right.makerAssetFilledAmount = rightMakerAssetAmountRemaining;
            matchedFillResults.right.takerAssetFilledAmount = rightTakerAssetAmountRemaining;
            matchedFillResults.left.takerAssetFilledAmount = matchedFillResults.right.makerAssetFilledAmount;
            // Round down to ensure the maker's exchange rate does not exceed the price specified by the order. 
            // We favor the maker when the exchange rate must be rounded.
            matchedFillResults.left.makerAssetFilledAmount = safeGetPartialAmountFloor(
                leftOrder.makerAssetAmount,
                leftOrder.takerAssetAmount,
                matchedFillResults.left.takerAssetFilledAmount
            );
        } else {
            // Case 2: Left order is fully filled
            matchedFillResults.left.makerAssetFilledAmount = leftMakerAssetAmountRemaining;
            matchedFillResults.left.takerAssetFilledAmount = leftTakerAssetAmountRemaining;
            matchedFillResults.right.makerAssetFilledAmount = matchedFillResults.left.takerAssetFilledAmount;
            // Round up to ensure the maker's exchange rate does not exceed the price specified by the order.
            // We favor the maker when the exchange rate must be rounded.
            matchedFillResults.right.takerAssetFilledAmount = safeGetPartialAmountCeil(
                rightOrder.takerAssetAmount,
                rightOrder.makerAssetAmount,
                matchedFillResults.right.makerAssetFilledAmount
            );
        }

        // Calculate amount given to taker
        matchedFillResults.leftMakerAssetSpreadAmount = safeSub(
            matchedFillResults.left.makerAssetFilledAmount,
            matchedFillResults.right.takerAssetFilledAmount
        );

        // Compute fees for left order
        matchedFillResults.left.makerFeePaid = safeGetPartialAmountFloor(
            matchedFillResults.left.makerAssetFilledAmount,
            leftOrder.makerAssetAmount,
            leftOrder.makerFee
        );
        matchedFillResults.left.takerFeePaid = safeGetPartialAmountFloor(
            matchedFillResults.left.takerAssetFilledAmount,
            leftOrder.takerAssetAmount,
            leftOrder.takerFee
        );

        // Compute fees for right order
        matchedFillResults.right.makerFeePaid = safeGetPartialAmountFloor(
            matchedFillResults.right.makerAssetFilledAmount,
            rightOrder.makerAssetAmount,
            rightOrder.makerFee
        );
        matchedFillResults.right.takerFeePaid = safeGetPartialAmountFloor(
            matchedFillResults.right.takerAssetFilledAmount,
            rightOrder.takerAssetAmount,
            rightOrder.takerFee
        );

        // Return fill results
        return matchedFillResults;
    }

    /// @dev Settles matched order by transferring appropriate funds between order makers, taker, and fee recipient.
    /// @param leftOrder First matched order.
    /// @param rightOrder Second matched order.
    /// @param takerAddress Address that matched the orders. The taker receives the spread between orders as profit.
    /// @param matchedFillResults Struct holding amounts to transfer between makers, taker, and fee recipients.
    function settleMatchedOrders(
        LibOrder.Order memory leftOrder,
        LibOrder.Order memory rightOrder,
        address takerAddress,
        LibFillResults.MatchedFillResults memory matchedFillResults
    )
        private
    {
        bytes memory zrxAssetData = ZRX_ASSET_DATA;
        // Order makers and taker
        dispatchTransferFrom(
            leftOrder.makerAssetData,
            leftOrder.makerAddress,
            rightOrder.makerAddress,
            matchedFillResults.right.takerAssetFilledAmount
        );
        dispatchTransferFrom(
            rightOrder.makerAssetData,
            rightOrder.makerAddress,
            leftOrder.makerAddress,
            matchedFillResults.left.takerAssetFilledAmount
        );
        dispatchTransferFrom(
            leftOrder.makerAssetData,
            leftOrder.makerAddress,
            takerAddress,
            matchedFillResults.leftMakerAssetSpreadAmount
        );

        // Maker fees
        dispatchTransferFrom(
            zrxAssetData,
            leftOrder.makerAddress,
            leftOrder.feeRecipientAddress,
            matchedFillResults.left.makerFeePaid
        );
        dispatchTransferFrom(
            zrxAssetData,
            rightOrder.makerAddress,
            rightOrder.feeRecipientAddress,
            matchedFillResults.right.makerFeePaid
        );

        // Taker fees
        if (leftOrder.feeRecipientAddress == rightOrder.feeRecipientAddress) {
            dispatchTransferFrom(
                zrxAssetData,
                takerAddress,
                leftOrder.feeRecipientAddress,
                safeAdd(
                    matchedFillResults.left.takerFeePaid,
                    matchedFillResults.right.takerFeePaid
                )
            );
        } else {
            dispatchTransferFrom(
                zrxAssetData,
                takerAddress,
                leftOrder.feeRecipientAddress,
                matchedFillResults.left.takerFeePaid
            );
            dispatchTransferFrom(
                zrxAssetData,
                takerAddress,
                rightOrder.feeRecipientAddress,
                matchedFillResults.right.takerFeePaid
            );
        }
    }
}



// solhint-disable no-empty-blocks
contract Exchange is
    MixinExchangeCore,
    MixinMatchOrders,
    MixinSignatureValidator,
    MixinTransactions,
    MixinAssetProxyDispatcher,
    MixinWrapperFunctions
{
    string constant public VERSION = "2.0.1-alpha";

    // Mixins are instantiated in the order they are inherited
    constructor (bytes memory _zrxAssetData)
        public
        LibConstants(_zrxAssetData) // @TODO: Remove when we deploy.
        MixinExchangeCore()
        MixinMatchOrders()
        MixinSignatureValidator()
        MixinTransactions()
        MixinAssetProxyDispatcher()
        MixinWrapperFunctions()
    {}
}

// Copyright (C) 2015, 2016, 2017 Dapphub

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.4.18;

contract WETH9 {
    string public name     = "Wrapped Ether";
    string public symbol   = "WETH";
    uint8  public decimals = 18;

    event  Approval(address indexed src, address indexed guy, uint wad);
    event  Transfer(address indexed src, address indexed dst, uint wad);
    event  Deposit(address indexed dst, uint wad);
    event  Withdrawal(address indexed src, uint wad);

    mapping (address => uint)                       public  balanceOf;
    mapping (address => mapping (address => uint))  public  allowance;

    function() public payable {
        deposit();
    }
    function deposit() public payable {
        balanceOf[msg.sender] += msg.value;
        Deposit(msg.sender, msg.value);
    }
    function withdraw(uint wad) public {
        require(balanceOf[msg.sender] >= wad);
        balanceOf[msg.sender] -= wad;
        msg.sender.transfer(wad);
        Withdrawal(msg.sender, wad);
    }

    function totalSupply() public view returns (uint) {
        return this.balance;
    }

    function approve(address guy, uint wad) public returns (bool) {
        allowance[msg.sender][guy] = wad;
        Approval(msg.sender, guy, wad);
        return true;
    }

    function transfer(address dst, uint wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        returns (bool)
    {
        require(balanceOf[src] >= wad);

        if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
            require(allowance[src][msg.sender] >= wad);
            allowance[src][msg.sender] -= wad;
        }

        balanceOf[src] -= wad;
        balanceOf[dst] += wad;

        Transfer(src, dst, wad);

        return true;
    }
}


/*
                    GNU GENERAL PUBLIC LICENSE
                       Version 3, 29 June 2007

 Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

                            Preamble

  The GNU General Public License is a free, copyleft license for
software and other kinds of works.

  The licenses for most software and other practical works are designed
to take away your freedom to share and change the works.  By contrast,
the GNU General Public License is intended to guarantee your freedom to
share and change all versions of a program--to make sure it remains free
software for all its users.  We, the Free Software Foundation, use the
GNU General Public License for most of our software; it applies also to
any other work released this way by its authors.  You can apply it to
your programs, too.

  When we speak of free software, we are referring to freedom, not
price.  Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
them if you wish), that you receive source code or can get it if you
want it, that you can change the software or use pieces of it in new
free programs, and that you know you can do these things.

  To protect your rights, we need to prevent others from denying you
these rights or asking you to surrender the rights.  Therefore, you have
certain responsibilities if you distribute copies of the software, or if
you modify it: responsibilities to respect the freedom of others.

  For example, if you distribute copies of such a program, whether
gratis or for a fee, you must pass on to the recipients the same
freedoms that you received.  You must make sure that they, too, receive
or can get the source code.  And you must show them these terms so they
know their rights.

  Developers that use the GNU GPL protect your rights with two steps:
(1) assert copyright on the software, and (2) offer you this License
giving you legal permission to copy, distribute and/or modify it.

  For the developers' and authors' protection, the GPL clearly explains
that there is no warranty for this free software.  For both users' and
authors' sake, the GPL requires that modified versions be marked as
changed, so that their problems will not be attributed erroneously to
authors of previous versions.

  Some devices are designed to deny users access to install or run
modified versions of the software inside them, although the manufacturer
can do so.  This is fundamentally incompatible with the aim of
protecting users' freedom to change the software.  The systematic
pattern of such abuse occurs in the area of products for individuals to
use, which is precisely where it is most unacceptable.  Therefore, we
have designed this version of the GPL to prohibit the practice for those
products.  If such problems arise substantially in other domains, we
stand ready to extend this provision to those domains in future versions
of the GPL, as needed to protect the freedom of users.

  Finally, every program is threatened constantly by software patents.
States should not allow patents to restrict development and use of
software on general-purpose computers, but in those that do, we wish to
avoid the special danger that patents applied to a free program could
make it effectively proprietary.  To prevent this, the GPL assures that
patents cannot be used to render the program non-free.

  The precise terms and conditions for copying, distribution and
modification follow.

                       TERMS AND CONDITIONS

  0. Definitions.

  "This License" refers to version 3 of the GNU General Public License.

  "Copyright" also means copyright-like laws that apply to other kinds of
works, such as semiconductor masks.

  "The Program" refers to any copyrightable work licensed under this
License.  Each licensee is addressed as "you".  "Licensees" and
"recipients" may be individuals or organizations.

  To "modify" a work means to copy from or adapt all or part of the work
in a fashion requiring copyright permission, other than the making of an
exact copy.  The resulting work is called a "modified version" of the
earlier work or a work "based on" the earlier work.

  A "covered work" means either the unmodified Program or a work based
on the Program.

  To "propagate" a work means to do anything with it that, without
permission, would make you directly or secondarily liable for
infringement under applicable copyright law, except executing it on a
computer or modifying a private copy.  Propagation includes copying,
distribution (with or without modification), making available to the
public, and in some countries other activities as well.

  To "convey" a work means any kind of propagation that enables other
parties to make or receive copies.  Mere interaction with a user through
a computer network, with no transfer of a copy, is not conveying.

  An interactive user interface displays "Appropriate Legal Notices"
to the extent that it includes a convenient and prominently visible
feature that (1) displays an appropriate copyright notice, and (2)
tells the user that there is no warranty for the work (except to the
extent that warranties are provided), that licensees may convey the
work under this License, and how to view a copy of this License.  If
the interface presents a list of user commands or options, such as a
menu, a prominent item in the list meets this criterion.

  1. Source Code.

  The "source code" for a work means the preferred form of the work
for making modifications to it.  "Object code" means any non-source
form of a work.

  A "Standard Interface" means an interface that either is an official
standard defined by a recognized standards body, or, in the case of
interfaces specified for a particular programming language, one that
is widely used among developers working in that language.

  The "System Libraries" of an executable work include anything, other
than the work as a whole, that (a) is included in the normal form of
packaging a Major Component, but which is not part of that Major
Component, and (b) serves only to enable use of the work with that
Major Component, or to implement a Standard Interface for which an
implementation is available to the public in source code form.  A
"Major Component", in this context, means a major essential component
(kernel, window system, and so on) of the specific operating system
(if any) on which the executable work runs, or a compiler used to
produce the work, or an object code interpreter used to run it.

  The "Corresponding Source" for a work in object code form means all
the source code needed to generate, install, and (for an executable
work) run the object code and to modify the work, including scripts to
control those activities.  However, it does not include the work's
System Libraries, or general-purpose tools or generally available free
programs which are used unmodified in performing those activities but
which are not part of the work.  For example, Corresponding Source
includes interface definition files associated with source files for
the work, and the source code for shared libraries and dynamically
linked subprograms that the work is specifically designed to require,
such as by intimate data communication or control flow between those
subprograms and other parts of the work.

  The Corresponding Source need not include anything that users
can regenerate automatically from other parts of the Corresponding
Source.

  The Corresponding Source for a work in source code form is that
same work.

  2. Basic Permissions.

  All rights granted under this License are granted for the term of
copyright on the Program, and are irrevocable provided the stated
conditions are met.  This License explicitly affirms your unlimited
permission to run the unmodified Program.  The output from running a
covered work is covered by this License only if the output, given its
content, constitutes a covered work.  This License acknowledges your
rights of fair use or other equivalent, as provided by copyright law.

  You may make, run and propagate covered works that you do not
convey, without conditions so long as your license otherwise remains
in force.  You may convey covered works to others for the sole purpose
of having them make modifications exclusively for you, or provide you
with facilities for running those works, provided that you comply with
the terms of this License in conveying all material for which you do
not control copyright.  Those thus making or running the covered works
for you must do so exclusively on your behalf, under your direction
and control, on terms that prohibit them from making any copies of
your copyrighted material outside their relationship with you.

  Conveying under any other circumstances is permitted solely under
the conditions stated below.  Sublicensing is not allowed; section 10
makes it unnecessary.

  3. Protecting Users' Legal Rights From Anti-Circumvention Law.

  No covered work shall be deemed part of an effective technological
measure under any applicable law fulfilling obligations under article
11 of the WIPO copyright treaty adopted on 20 December 1996, or
similar laws prohibiting or restricting circumvention of such
measures.

  When you convey a covered work, you waive any legal power to forbid
circumvention of technological measures to the extent such circumvention
is effected by exercising rights under this License with respect to
the covered work, and you disclaim any intention to limit operation or
modification of the work as a means of enforcing, against the work's
users, your or third parties' legal rights to forbid circumvention of
technological measures.

  4. Conveying Verbatim Copies.

  You may convey verbatim copies of the Program's source code as you
receive it, in any medium, provided that you conspicuously and
appropriately publish on each copy an appropriate copyright notice;
keep intact all notices stating that this License and any
non-permissive terms added in accord with section 7 apply to the code;
keep intact all notices of the absence of any warranty; and give all
recipients a copy of this License along with the Program.

  You may charge any price or no price for each copy that you convey,
and you may offer support or warranty protection for a fee.

  5. Conveying Modified Source Versions.

  You may convey a work based on the Program, or the modifications to
produce it from the Program, in the form of source code under the
terms of section 4, provided that you also meet all of these conditions:

    a) The work must carry prominent notices stating that you modified
    it, and giving a relevant date.

    b) The work must carry prominent notices stating that it is
    released under this License and any conditions added under section
    7.  This requirement modifies the requirement in section 4 to
    "keep intact all notices".

    c) You must license the entire work, as a whole, under this
    License to anyone who comes into possession of a copy.  This
    License will therefore apply, along with any applicable section 7
    additional terms, to the whole of the work, and all its parts,
    regardless of how they are packaged.  This License gives no
    permission to license the work in any other way, but it does not
    invalidate such permission if you have separately received it.

    d) If the work has interactive user interfaces, each must display
    Appropriate Legal Notices; however, if the Program has interactive
    interfaces that do not display Appropriate Legal Notices, your
    work need not make them do so.

  A compilation of a covered work with other separate and independent
works, which are not by their nature extensions of the covered work,
and which are not combined with it such as to form a larger program,
in or on a volume of a storage or distribution medium, is called an
"aggregate" if the compilation and its resulting copyright are not
used to limit the access or legal rights of the compilation's users
beyond what the individual works permit.  Inclusion of a covered work
in an aggregate does not cause this License to apply to the other
parts of the aggregate.

  6. Conveying Non-Source Forms.

  You may convey a covered work in object code form under the terms
of sections 4 and 5, provided that you also convey the
machine-readable Corresponding Source under the terms of this License,
in one of these ways:

    a) Convey the object code in, or embodied in, a physical product
    (including a physical distribution medium), accompanied by the
    Corresponding Source fixed on a durable physical medium
    customarily used for software interchange.

    b) Convey the object code in, or embodied in, a physical product
    (including a physical distribution medium), accompanied by a
    written offer, valid for at least three years and valid for as
    long as you offer spare parts or customer support for that product
    model, to give anyone who possesses the object code either (1) a
    copy of the Corresponding Source for all the software in the
    product that is covered by this License, on a durable physical
    medium customarily used for software interchange, for a price no
    more than your reasonable cost of physically performing this
    conveying of source, or (2) access to copy the
    Corresponding Source from a network server at no charge.

    c) Convey individual copies of the object code with a copy of the
    written offer to provide the Corresponding Source.  This
    alternative is allowed only occasionally and noncommercially, and
    only if you received the object code with such an offer, in accord
    with subsection 6b.

    d) Convey the object code by offering access from a designated
    place (gratis or for a charge), and offer equivalent access to the
    Corresponding Source in the same way through the same place at no
    further charge.  You need not require recipients to copy the
    Corresponding Source along with the object code.  If the place to
    copy the object code is a network server, the Corresponding Source
    may be on a different server (operated by you or a third party)
    that supports equivalent copying facilities, provided you maintain
    clear directions next to the object code saying where to find the
    Corresponding Source.  Regardless of what server hosts the
    Corresponding Source, you remain obligated to ensure that it is
    available for as long as needed to satisfy these requirements.

    e) Convey the object code using peer-to-peer transmission, provided
    you inform other peers where the object code and Corresponding
    Source of the work are being offered to the general public at no
    charge under subsection 6d.

  A separable portion of the object code, whose source code is excluded
from the Corresponding Source as a System Library, need not be
included in conveying the object code work.

  A "User Product" is either (1) a "consumer product", which means any
tangible personal property which is normally used for personal, family,
or household purposes, or (2) anything designed or sold for incorporation
into a dwelling.  In determining whether a product is a consumer product,
doubtful cases shall be resolved in favor of coverage.  For a particular
product received by a particular user, "normally used" refers to a
typical or common use of that class of product, regardless of the status
of the particular user or of the way in which the particular user
actually uses, or expects or is expected to use, the product.  A product
is a consumer product regardless of whether the product has substantial
commercial, industrial or non-consumer uses, unless such uses represent
the only significant mode of use of the product.

  "Installation Information" for a User Product means any methods,
procedures, authorization keys, or other information required to install
and execute modified versions of a covered work in that User Product from
a modified version of its Corresponding Source.  The information must
suffice to ensure that the continued functioning of the modified object
code is in no case prevented or interfered with solely because
modification has been made.

  If you convey an object code work under this section in, or with, or
specifically for use in, a User Product, and the conveying occurs as
part of a transaction in which the right of possession and use of the
User Product is transferred to the recipient in perpetuity or for a
fixed term (regardless of how the transaction is characterized), the
Corresponding Source conveyed under this section must be accompanied
by the Installation Information.  But this requirement does not apply
if neither you nor any third party retains the ability to install
modified object code on the User Product (for example, the work has
been installed in ROM).

  The requirement to provide Installation Information does not include a
requirement to continue to provide support service, warranty, or updates
for a work that has been modified or installed by the recipient, or for
the User Product in which it has been modified or installed.  Access to a
network may be denied when the modification itself materially and
adversely affects the operation of the network or violates the rules and
protocols for communication across the network.

  Corresponding Source conveyed, and Installation Information provided,
in accord with this section must be in a format that is publicly
documented (and with an implementation available to the public in
source code form), and must require no special password or key for
unpacking, reading or copying.

  7. Additional Terms.

  "Additional permissions" are terms that supplement the terms of this
License by making exceptions from one or more of its conditions.
Additional permissions that are applicable to the entire Program shall
be treated as though they were included in this License, to the extent
that they are valid under applicable law.  If additional permissions
apply only to part of the Program, that part may be used separately
under those permissions, but the entire Program remains governed by
this License without regard to the additional permissions.

  When you convey a copy of a covered work, you may at your option
remove any additional permissions from that copy, or from any part of
it.  (Additional permissions may be written to require their own
removal in certain cases when you modify the work.)  You may place
additional permissions on material, added by you to a covered work,
for which you have or can give appropriate copyright permission.

  Notwithstanding any other provision of this License, for material you
add to a covered work, you may (if authorized by the copyright holders of
that material) supplement the terms of this License with terms:

    a) Disclaiming warranty or limiting liability differently from the
    terms of sections 15 and 16 of this License; or

    b) Requiring preservation of specified reasonable legal notices or
    author attributions in that material or in the Appropriate Legal
    Notices displayed by works containing it; or

    c) Prohibiting misrepresentation of the origin of that material, or
    requiring that modified versions of such material be marked in
    reasonable ways as different from the original version; or

    d) Limiting the use for publicity purposes of names of licensors or
    authors of the material; or

    e) Declining to grant rights under trademark law for use of some
    trade names, trademarks, or service marks; or

    f) Requiring indemnification of licensors and authors of that
    material by anyone who conveys the material (or modified versions of
    it) with contractual assumptions of liability to the recipient, for
    any liability that these contractual assumptions directly impose on
    those licensors and authors.

  All other non-permissive additional terms are considered "further
restrictions" within the meaning of section 10.  If the Program as you
received it, or any part of it, contains a notice stating that it is
governed by this License along with a term that is a further
restriction, you may remove that term.  If a license document contains
a further restriction but permits relicensing or conveying under this
License, you may add to a covered work material governed by the terms
of that license document, provided that the further restriction does
not survive such relicensing or conveying.

  If you add terms to a covered work in accord with this section, you
must place, in the relevant source files, a statement of the
additional terms that apply to those files, or a notice indicating
where to find the applicable terms.

  Additional terms, permissive or non-permissive, may be stated in the
form of a separately written license, or stated as exceptions;
the above requirements apply either way.

  8. Termination.

  You may not propagate or modify a covered work except as expressly
provided under this License.  Any attempt otherwise to propagate or
modify it is void, and will automatically terminate your rights under
this License (including any patent licenses granted under the third
paragraph of section 11).

  However, if you cease all violation of this License, then your
license from a particular copyright holder is reinstated (a)
provisionally, unless and until the copyright holder explicitly and
finally terminates your license, and (b) permanently, if the copyright
holder fails to notify you of the violation by some reasonable means
prior to 60 days after the cessation.

  Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from that
copyright holder, and you cure the violation prior to 30 days after
your receipt of the notice.

  Termination of your rights under this section does not terminate the
licenses of parties who have received copies or rights from you under
this License.  If your rights have been terminated and not permanently
reinstated, you do not qualify to receive new licenses for the same
material under section 10.

  9. Acceptance Not Required for Having Copies.

  You are not required to accept this License in order to receive or
run a copy of the Program.  Ancillary propagation of a covered work
occurring solely as a consequence of using peer-to-peer transmission
to receive a copy likewise does not require acceptance.  However,
nothing other than this License grants you permission to propagate or
modify any covered work.  These actions infringe copyright if you do
not accept this License.  Therefore, by modifying or propagating a
covered work, you indicate your acceptance of this License to do so.

  10. Automatic Licensing of Downstream Recipients.

  Each time you convey a covered work, the recipient automatically
receives a license from the original licensors, to run, modify and
propagate that work, subject to this License.  You are not responsible
for enforcing compliance by third parties with this License.

  An "entity transaction" is a transaction transferring control of an
organization, or substantially all assets of one, or subdividing an
organization, or merging organizations.  If propagation of a covered
work results from an entity transaction, each party to that
transaction who receives a copy of the work also receives whatever
licenses to the work the party's predecessor in interest had or could
give under the previous paragraph, plus a right to possession of the
Corresponding Source of the work from the predecessor in interest, if
the predecessor has it or can get it with reasonable efforts.

  You may not impose any further restrictions on the exercise of the
rights granted or affirmed under this License.  For example, you may
not impose a license fee, royalty, or other charge for exercise of
rights granted under this License, and you may not initiate litigation
(including a cross-claim or counterclaim in a lawsuit) alleging that
any patent claim is infringed by making, using, selling, offering for
sale, or importing the Program or any portion of it.

  11. Patents.

  A "contributor" is a copyright holder who authorizes use under this
License of the Program or a work on which the Program is based.  The
work thus licensed is called the contributor's "contributor version".

  A contributor's "essential patent claims" are all patent claims
owned or controlled by the contributor, whether already acquired or
hereafter acquired, that would be infringed by some manner, permitted
by this License, of making, using, or selling its contributor version,
but do not include claims that would be infringed only as a
consequence of further modification of the contributor version.  For
purposes of this definition, "control" includes the right to grant
patent sublicenses in a manner consistent with the requirements of
this License.

  Each contributor grants you a non-exclusive, worldwide, royalty-free
patent license under the contributor's essential patent claims, to
make, use, sell, offer for sale, import and otherwise run, modify and
propagate the contents of its contributor version.

  In the following three paragraphs, a "patent license" is any express
agreement or commitment, however denominated, not to enforce a patent
(such as an express permission to practice a patent or covenant not to
sue for patent infringement).  To "grant" such a patent license to a
party means to make such an agreement or commitment not to enforce a
patent against the party.

  If you convey a covered work, knowingly relying on a patent license,
and the Corresponding Source of the work is not available for anyone
to copy, free of charge and under the terms of this License, through a
publicly available network server or other readily accessible means,
then you must either (1) cause the Corresponding Source to be so
available, or (2) arrange to deprive yourself of the benefit of the
patent license for this particular work, or (3) arrange, in a manner
consistent with the requirements of this License, to extend the patent
license to downstream recipients.  "Knowingly relying" means you have
actual knowledge that, but for the patent license, your conveying the
covered work in a country, or your recipient's use of the covered work
in a country, would infringe one or more identifiable patents in that
country that you have reason to believe are valid.

  If, pursuant to or in connection with a single transaction or
arrangement, you convey, or propagate by procuring conveyance of, a
covered work, and grant a patent license to some of the parties
receiving the covered work authorizing them to use, propagate, modify
or convey a specific copy of the covered work, then the patent license
you grant is automatically extended to all recipients of the covered
work and works based on it.

  A patent license is "discriminatory" if it does not include within
the scope of its coverage, prohibits the exercise of, or is
conditioned on the non-exercise of one or more of the rights that are
specifically granted under this License.  You may not convey a covered
work if you are a party to an arrangement with a third party that is
in the business of distributing software, under which you make payment
to the third party based on the extent of your activity of conveying
the work, and under which the third party grants, to any of the
parties who would receive the covered work from you, a discriminatory
patent license (a) in connection with copies of the covered work
conveyed by you (or copies made from those copies), or (b) primarily
for and in connection with specific products or compilations that
contain the covered work, unless you entered into that arrangement,
or that patent license was granted, prior to 28 March 2007.

  Nothing in this License shall be construed as excluding or limiting
any implied license or other defenses to infringement that may
otherwise be available to you under applicable patent law.

  12. No Surrender of Others' Freedom.

  If conditions are imposed on you (whether by court order, agreement or
otherwise) that contradict the conditions of this License, they do not
excuse you from the conditions of this License.  If you cannot convey a
covered work so as to satisfy simultaneously your obligations under this
License and any other pertinent obligations, then as a consequence you may
not convey it at all.  For example, if you agree to terms that obligate you
to collect a royalty for further conveying from those to whom you convey
the Program, the only way you could satisfy both those terms and this
License would be to refrain entirely from conveying the Program.

  13. Use with the GNU Affero General Public License.

  Notwithstanding any other provision of this License, you have
permission to link or combine any covered work with a work licensed
under version 3 of the GNU Affero General Public License into a single
combined work, and to convey the resulting work.  The terms of this
License will continue to apply to the part which is the covered work,
but the special requirements of the GNU Affero General Public License,
section 13, concerning interaction through a network will apply to the
combination as such.

  14. Revised Versions of this License.

  The Free Software Foundation may publish revised and/or new versions of
the GNU General Public License from time to time.  Such new versions will
be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.

  Each version is given a distinguishing version number.  If the
Program specifies that a certain numbered version of the GNU General
Public License "or any later version" applies to it, you have the
option of following the terms and conditions either of that numbered
version or of any later version published by the Free Software
Foundation.  If the Program does not specify a version number of the
GNU General Public License, you may choose any version ever published
by the Free Software Foundation.

  If the Program specifies that a proxy can decide which future
versions of the GNU General Public License can be used, that proxy's
public statement of acceptance of a version permanently authorizes you
to choose that version for the Program.

  Later license versions may give you additional or different
permissions.  However, no additional obligations are imposed on any
author or copyright holder as a result of your choosing to follow a
later version.

  15. Disclaimer of Warranty.

  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

  16. Limitation of Liability.

  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES.

  17. Interpretation of Sections 15 and 16.

  If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely approximates
an absolute waiver of all civil liability in connection with the
Program, unless a warranty or assumption of liability accompanies a
copy of the Program in return for a fee.

                     END OF TERMS AND CONDITIONS

            How to Apply These Terms to Your New Programs

  If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

  To do so, attach the following notices to the program.  It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.

    <one line to give the program's name and a brief idea of what it does.>
    Copyright (C) <year>  <name of author>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

Also add information on how to contact you by electronic and paper mail.

  If the program does terminal interaction, make it output a short
notice like this when it starts in an interactive mode:

    <program>  Copyright (C) <year>  <name of author>
    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
    This is free software, and you are welcome to redistribute it
    under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License.  Of course, your program's commands
might be different; for a GUI interface, you would use an "about box".

  You should also get your employer (if you work as a programmer) or school,
if any, to sign a "copyright disclaimer" for the program, if necessary.
For more information on this, and how to apply and follow the GNU GPL, see
<http://www.gnu.org/licenses/>.

  The GNU General Public License does not permit incorporating your program
into proprietary programs.  If your program is a subroutine library, you
may consider it more useful to permit linking proprietary applications with
the library.  If this is what you want to do, use the GNU Lesser General
Public License instead of this License.  But first, please read
<http://www.gnu.org/philosophy/why-not-lgpl.html>.

*/

/**
 *Submitted for verification at Etherscan.io on 2020-02-03
*/

// File: contracts/zeppelin/SafeMath.sol

pragma solidity ^0.4.24;


/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
    /**
    * @dev Subtracts two numbers, reverts on overflow (i.e. if subtrahend is greater than minuend).
    */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

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

        return c;
    }
}

// File: contracts/PAXImplementationV2.sol

pragma solidity ^0.4.24;
pragma experimental "v0.5.0";



/**
 * @title PAXImplementationV2
 * @dev this contract is a Pausable ERC20 token with Burn and Mint
 * controlled by a central SupplyController. By implementing PaxosImplementation
 * this contract also includes external methods for setting
 * a new implementation contract for the Proxy.
 * NOTE: The storage defined here will actually be held in the Proxy
 * contract and all calls to this contract should be made through
 * the proxy, including admin actions done as owner or supplyController.
 * Any call to transfer against this contract should fail
 * with insufficient funds since no tokens will be issued there.
 */
contract PAXImplementationV2 {

    /**
     * MATH
     */

    using SafeMath for uint256;

    /**
     * DATA
     */

    // INITIALIZATION DATA
    bool private initialized = false;

    // ERC20 BASIC DATA
    mapping(address => uint256) internal balances;
    uint256 internal totalSupply_;
    string public constant name = "Paxos Standard"; // solium-disable-line
    string public constant symbol = "PAX"; // solium-disable-line uppercase
    uint8 public constant decimals = 18; // solium-disable-line uppercase

    // ERC20 DATA
    mapping(address => mapping(address => uint256)) internal allowed;

    // OWNER DATA PART 1
    address public owner;

    // PAUSABILITY DATA
    bool public paused = false;

    // ASSET PROTECTION DATA
    address public assetProtectionRole;
    mapping(address => bool) internal frozen;

    // SUPPLY CONTROL DATA
    address public supplyController;

    // OWNER DATA PART 2
    address public proposedOwner;

    // DELEGATED TRANSFER DATA
    address public betaDelegateWhitelister;
    mapping(address => bool) internal betaDelegateWhitelist;
    mapping(address => uint256) internal nextSeqs;
    // EIP191 header for EIP712 prefix
    string constant internal EIP191_HEADER = "\x19\x01";
    // Hash of the EIP712 Domain Separator Schema
    bytes32 constant internal EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH = keccak256(
        "EIP712Domain(string name,address verifyingContract)"
    );
    bytes32 constant internal EIP712_DELEGATED_TRANSFER_SCHEMA_HASH = keccak256(
        "BetaDelegatedTransfer(address to,uint256 value,uint256 fee,uint256 seq,uint256 deadline)"
    );
    // Hash of the EIP712 Domain Separator data
    // solhint-disable-next-line var-name-mixedcase
    bytes32 public EIP712_DOMAIN_HASH;

    /**
     * EVENTS
     */

    // ERC20 BASIC EVENTS
    event Transfer(address indexed from, address indexed to, uint256 value);

    // ERC20 EVENTS
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );

    // OWNABLE EVENTS
    event OwnershipTransferProposed(
        address indexed currentOwner,
        address indexed proposedOwner
    );
    event OwnershipTransferDisregarded(
        address indexed oldProposedOwner
    );
    event OwnershipTransferred(
        address indexed oldOwner,
        address indexed newOwner
    );

    // PAUSABLE EVENTS
    event Pause();
    event Unpause();

    // ASSET PROTECTION EVENTS
    event AddressFrozen(address indexed addr);
    event AddressUnfrozen(address indexed addr);
    event FrozenAddressWiped(address indexed addr);
    event AssetProtectionRoleSet (
        address indexed oldAssetProtectionRole,
        address indexed newAssetProtectionRole
    );

    // SUPPLY CONTROL EVENTS
    event SupplyIncreased(address indexed to, uint256 value);
    event SupplyDecreased(address indexed from, uint256 value);
    event SupplyControllerSet(
        address indexed oldSupplyController,
        address indexed newSupplyController
    );

    // DELEGATED TRANSFER EVENTS
    event BetaDelegatedTransfer(
        address indexed from, address indexed to, uint256 value, uint256 seq, uint256 fee
    );
    event BetaDelegateWhitelisterSet(
        address indexed oldWhitelister,
        address indexed newWhitelister
    );
    event BetaDelegateWhitelisted(address indexed newDelegate);
    event BetaDelegateUnwhitelisted(address indexed oldDelegate);

    /**
     * FUNCTIONALITY
     */

    // INITIALIZATION FUNCTIONALITY

    /**
     * @dev sets 0 initials tokens, the owner, and the supplyController.
     * this serves as the constructor for the proxy but compiles to the
     * memory model of the Implementation contract.
     */
    function initialize() public {
        require(!initialized, "already initialized");
        owner = msg.sender;
        assetProtectionRole = address(0);
        totalSupply_ = 0;
        supplyController = msg.sender;
        initialized = true;
    }

    /**
     * The constructor is used here to ensure that the implementation
     * contract is initialized. An uncontrolled implementation
     * contract might lead to misleading state
     * for users who accidentally interact with it.
     */
    constructor() public {
        initialize();
        pause();
        // Added in V2
        initializeDomainSeparator();
    }

    /**
     * @dev To be called when upgrading the contract using upgradeAndCall to add delegated transfers
     */
    function initializeDomainSeparator() public {
        // hash the name context with the contract address
        EIP712_DOMAIN_HASH = keccak256(abi.encodePacked(// solium-disable-line
                EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH,
                keccak256(bytes(name)),
                bytes32(address(this))
            ));
        proposedOwner = address(0);
    }

    // ERC20 BASIC FUNCTIONALITY

    /**
    * @dev Total number of tokens in existence
    */
    function totalSupply() public view returns (uint256) {
        return totalSupply_;
    }

    /**
    * @dev Transfer token to a specified address from msg.sender
    * Note: the use of Safemath ensures that _value is nonnegative.
    * @param _to The address to transfer to.
    * @param _value The amount to be transferred.
    */
    function transfer(address _to, uint256 _value) public whenNotPaused returns (bool) {
        require(_to != address(0), "cannot transfer to address zero");
        require(!frozen[_to] && !frozen[msg.sender], "address frozen");
        require(_value <= balances[msg.sender], "insufficient funds");

        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        emit Transfer(msg.sender, _to, _value);
        return true;
    }

    /**
    * @dev Gets the balance of the specified address.
    * @param _addr The address to query the the balance of.
    * @return An uint256 representing the amount owned by the passed address.
    */
    function balanceOf(address _addr) public view returns (uint256) {
        return balances[_addr];
    }

    // ERC20 FUNCTIONALITY

    /**
     * @dev Transfer tokens from one address to another
     * @param _from address The address which you want to send tokens from
     * @param _to address The address which you want to transfer to
     * @param _value uint256 the amount of tokens to be transferred
     */
    function transferFrom(
        address _from,
        address _to,
        uint256 _value
    )
    public
    whenNotPaused
    returns (bool)
    {
        require(_to != address(0), "cannot transfer to address zero");
        require(!frozen[_to] && !frozen[_from] && !frozen[msg.sender], "address frozen");
        require(_value <= balances[_from], "insufficient funds");
        require(_value <= allowed[_from][msg.sender], "insufficient allowance");

        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(_value);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
        emit Transfer(_from, _to, _value);
        return true;
    }

    /**
     * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
     * Beware that changing an allowance with this method brings the risk that someone may use both the old
     * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
     * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     * @param _spender The address which will spend the funds.
     * @param _value The amount of tokens to be spent.
     */
    function approve(address _spender, uint256 _value) public whenNotPaused returns (bool) {
        require(!frozen[_spender] && !frozen[msg.sender], "address frozen");
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    /**
     * @dev Function to check the amount of tokens that an owner allowed to a spender.
     * @param _owner address The address which owns the funds.
     * @param _spender address The address which will spend the funds.
     * @return A uint256 specifying the amount of tokens still available for the spender.
     */
    function allowance(
        address _owner,
        address _spender
    )
    public
    view
    returns (uint256)
    {
        return allowed[_owner][_spender];
    }

    // OWNER FUNCTIONALITY

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

    /**
         * @dev Allows the current owner to begin transferring control of the contract to a proposedOwner
         * @param _proposedOwner The address to transfer ownership to.
         */
    function proposeOwner(address _proposedOwner) public onlyOwner {
        require(_proposedOwner != address(0), "cannot transfer ownership to address zero");
        require(msg.sender != _proposedOwner, "caller already is owner");
        proposedOwner = _proposedOwner;
        emit OwnershipTransferProposed(owner, proposedOwner);
    }
    /**
     * @dev Allows the current owner or proposed owner to cancel transferring control of the contract to a proposedOwner
     */
    function disregardProposeOwner() public {
        require(msg.sender == proposedOwner || msg.sender == owner, "only proposedOwner or owner");
        require(proposedOwner != address(0), "can only disregard a proposed owner that was previously set");
        address _oldProposedOwner = proposedOwner;
        proposedOwner = address(0);
        emit OwnershipTransferDisregarded(_oldProposedOwner);
    }
    /**
     * @dev Allows the proposed owner to complete transferring control of the contract to the proposedOwner.
     */
    function claimOwnership() public {
        require(msg.sender == proposedOwner, "onlyProposedOwner");
        address _oldOwner = owner;
        owner = proposedOwner;
        proposedOwner = address(0);
        emit OwnershipTransferred(_oldOwner, owner);
    }

    /**
     * @dev Reclaim all PAX at the contract address.
     * This sends the PAX tokens that this contract add holding to the owner.
     * Note: this is not affected by freeze constraints.
     */
    function reclaimPAX() external onlyOwner {
        uint256 _balance = balances[this];
        balances[this] = 0;
        balances[owner] = balances[owner].add(_balance);
        emit Transfer(this, owner, _balance);
    }

    // PAUSABILITY FUNCTIONALITY

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

    /**
     * @dev called by the owner to pause, triggers stopped state
     */
    function pause() public onlyOwner {
        require(!paused, "already paused");
        paused = true;
        emit Pause();
    }

    /**
     * @dev called by the owner to unpause, returns to normal state
     */
    function unpause() public onlyOwner {
        require(paused, "already unpaused");
        paused = false;
        emit Unpause();
    }

    // ASSET PROTECTION FUNCTIONALITY

    /**
     * @dev Sets a new asset protection role address.
     * @param _newAssetProtectionRole The new address allowed to freeze/unfreeze addresses and seize their tokens.
     */
    function setAssetProtectionRole(address _newAssetProtectionRole) public {
        require(msg.sender == assetProtectionRole || msg.sender == owner, "only assetProtectionRole or Owner");
        emit AssetProtectionRoleSet(assetProtectionRole, _newAssetProtectionRole);
        assetProtectionRole = _newAssetProtectionRole;
    }

    modifier onlyAssetProtectionRole() {
        require(msg.sender == assetProtectionRole, "onlyAssetProtectionRole");
        _;
    }

    /**
     * @dev Freezes an address balance from being transferred.
     * @param _addr The new address to freeze.
     */
    function freeze(address _addr) public onlyAssetProtectionRole {
        require(!frozen[_addr], "address already frozen");
        frozen[_addr] = true;
        emit AddressFrozen(_addr);
    }

    /**
     * @dev Unfreezes an address balance allowing transfer.
     * @param _addr The new address to unfreeze.
     */
    function unfreeze(address _addr) public onlyAssetProtectionRole {
        require(frozen[_addr], "address already unfrozen");
        frozen[_addr] = false;
        emit AddressUnfrozen(_addr);
    }

    /**
     * @dev Wipes the balance of a frozen address, burning the tokens
     * and setting the approval to zero.
     * @param _addr The new frozen address to wipe.
     */
    function wipeFrozenAddress(address _addr) public onlyAssetProtectionRole {
        require(frozen[_addr], "address is not frozen");
        uint256 _balance = balances[_addr];
        balances[_addr] = 0;
        totalSupply_ = totalSupply_.sub(_balance);
        emit FrozenAddressWiped(_addr);
        emit SupplyDecreased(_addr, _balance);
        emit Transfer(_addr, address(0), _balance);
    }

    /**
    * @dev Gets whether the address is currently frozen.
    * @param _addr The address to check if frozen.
    * @return A bool representing whether the given address is frozen.
    */
    function isFrozen(address _addr) public view returns (bool) {
        return frozen[_addr];
    }

    // SUPPLY CONTROL FUNCTIONALITY

    /**
     * @dev Sets a new supply controller address.
     * @param _newSupplyController The address allowed to burn/mint tokens to control supply.
     */
    function setSupplyController(address _newSupplyController) public {
        require(msg.sender == supplyController || msg.sender == owner, "only SupplyController or Owner");
        require(_newSupplyController != address(0), "cannot set supply controller to address zero");
        emit SupplyControllerSet(supplyController, _newSupplyController);
        supplyController = _newSupplyController;
    }

    modifier onlySupplyController() {
        require(msg.sender == supplyController, "onlySupplyController");
        _;
    }

    /**
     * @dev Increases the total supply by minting the specified number of tokens to the supply controller account.
     * @param _value The number of tokens to add.
     * @return A boolean that indicates if the operation was successful.
     */
    function increaseSupply(uint256 _value) public onlySupplyController returns (bool success) {
        totalSupply_ = totalSupply_.add(_value);
        balances[supplyController] = balances[supplyController].add(_value);
        emit SupplyIncreased(supplyController, _value);
        emit Transfer(address(0), supplyController, _value);
        return true;
    }

    /**
     * @dev Decreases the total supply by burning the specified number of tokens from the supply controller account.
     * @param _value The number of tokens to remove.
     * @return A boolean that indicates if the operation was successful.
     */
    function decreaseSupply(uint256 _value) public onlySupplyController returns (bool success) {
        require(_value <= balances[supplyController], "not enough supply");
        balances[supplyController] = balances[supplyController].sub(_value);
        totalSupply_ = totalSupply_.sub(_value);
        emit SupplyDecreased(supplyController, _value);
        emit Transfer(supplyController, address(0), _value);
        return true;
    }

    // DELEGATED TRANSFER FUNCTIONALITY

    /**
     * @dev returns the next seq for a target address.
     * The transactor must submit nextSeqOf(transactor) in the next transaction for it to be valid.
     * Note: that the seq context is specific to this smart contract.
     * @param target The target address.
     * @return the seq.
     */
    //
    function nextSeqOf(address target) public view returns (uint256) {
        return nextSeqs[target];
    }

    /**
     * @dev Performs a transfer on behalf of the from address, identified by its signature on the delegatedTransfer msg.
     * Splits a signature byte array into r,s,v for convenience.
     * @param sig the signature of the delgatedTransfer msg.
     * @param to The address to transfer to.
     * @param value The amount to be transferred.
     * @param fee an optional ERC20 fee paid to the executor of betaDelegatedTransfer by the from address.
     * @param seq a sequencing number included by the from address specific to this contract to protect from replays.
     * @param deadline a block number after which the pre-signed transaction has expired.
     * @return A boolean that indicates if the operation was successful.
     */
    function betaDelegatedTransfer(
        bytes sig, address to, uint256 value, uint256 fee, uint256 seq, uint256 deadline
    ) public returns (bool) {
        require(sig.length == 65, "signature should have length 65");
        bytes32 r;
        bytes32 s;
        uint8 v;
        assembly {
            r := mload(add(sig, 32))
            s := mload(add(sig, 64))
            v := byte(0, mload(add(sig, 96)))
        }
        require(_betaDelegatedTransfer(r, s, v, to, value, fee, seq, deadline), "failed transfer");
        return true;
    }

    /**
     * @dev Performs a transfer on behalf of the from address, identified by its signature on the betaDelegatedTransfer msg.
     * Note: both the delegate and transactor sign in the fees. The transactor, however,
     * has no control over the gas price, and therefore no control over the transaction time.
     * Beta prefix chosen to avoid a name clash with an emerging standard in ERC865 or elsewhere.
     * Internal to the contract - see betaDelegatedTransfer and betaDelegatedTransferBatch.
     * @param r the r signature of the delgatedTransfer msg.
     * @param s the s signature of the delgatedTransfer msg.
     * @param v the v signature of the delgatedTransfer msg.
     * @param to The address to transfer to.
     * @param value The amount to be transferred.
     * @param fee an optional ERC20 fee paid to the delegate of betaDelegatedTransfer by the from address.
     * @param seq a sequencing number included by the from address specific to this contract to protect from replays.
     * @param deadline a block number after which the pre-signed transaction has expired.
     * @return A boolean that indicates if the operation was successful.
     */
    function _betaDelegatedTransfer(
        bytes32 r, bytes32 s, uint8 v, address to, uint256 value, uint256 fee, uint256 seq, uint256 deadline
    ) internal whenNotPaused returns (bool) {
        require(betaDelegateWhitelist[msg.sender], "Beta feature only accepts whitelisted delegates");
        require(value > 0 || fee > 0, "cannot transfer zero tokens with zero fee");
        require(block.number <= deadline, "transaction expired");
        // prevent sig malleability from ecrecover()
        require(uint256(s) <= 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0, "signature incorrect");
        require(v == 27 || v == 28, "signature incorrect");

        // EIP712 scheme: https://github.com/ethereum/EIPs/blob/master/EIPS/eip-712.md
        bytes32 delegatedTransferHash = keccak256(abi.encodePacked(// solium-disable-line
                EIP712_DELEGATED_TRANSFER_SCHEMA_HASH, bytes32(to), value, fee, seq, deadline
            ));
        bytes32 hash = keccak256(abi.encodePacked(EIP191_HEADER, EIP712_DOMAIN_HASH, delegatedTransferHash));
        address _from = ecrecover(hash, v, r, s);

        require(_from != address(0), "error determining from address from signature");
        require(to != address(0), "canno use address zero");
        require(!frozen[to] && !frozen[_from] && !frozen[msg.sender], "address frozen");
        require(value.add(fee) <= balances[_from], "insufficient fund");
        require(nextSeqs[_from] == seq, "incorrect seq");

        nextSeqs[_from] = nextSeqs[_from].add(1);
        balances[_from] = balances[_from].sub(value.add(fee));
        if (fee != 0) {
            balances[msg.sender] = balances[msg.sender].add(fee);
            emit Transfer(_from, msg.sender, fee);
        }
        balances[to] = balances[to].add(value);
        emit Transfer(_from, to, value);

        emit BetaDelegatedTransfer(_from, to, value, seq, fee);
        return true;
    }

    /**
     * @dev Performs an atomic batch of transfers on behalf of the from addresses, identified by their signatures.
     * Lack of nested array support in arguments requires all arguments to be passed as equal size arrays where
     * delegated transfer number i is the combination of all arguments at index i
     * @param r the r signatures of the delgatedTransfer msg.
     * @param s the s signatures of the delgatedTransfer msg.
     * @param v the v signatures of the delgatedTransfer msg.
     * @param to The addresses to transfer to.
     * @param value The amounts to be transferred.
     * @param fee optional ERC20 fees paid to the delegate of betaDelegatedTransfer by the from address.
     * @param seq sequencing numbers included by the from address specific to this contract to protect from replays.
     * @param deadline block numbers after which the pre-signed transactions have expired.
     * @return A boolean that indicates if the operation was successful.
     */
    function betaDelegatedTransferBatch(
        bytes32[] r, bytes32[] s, uint8[] v, address[] to, uint256[] value, uint256[] fee, uint256[] seq, uint256[] deadline
    ) public returns (bool) {
        require(r.length == s.length && r.length == v.length && r.length == to.length && r.length == value.length, "length mismatch");
        require(r.length == fee.length && r.length == seq.length && r.length == deadline.length, "length mismatch");

        for (uint i = 0; i < r.length; i++) {
            require(
                _betaDelegatedTransfer(r[i], s[i], v[i], to[i], value[i], fee[i], seq[i], deadline[i]),
                "failed transfer"
            );
        }
        return true;
    }

    /**
    * @dev Gets whether the address is currently whitelisted for betaDelegateTransfer.
    * @param _addr The address to check if whitelisted.
    * @return A bool representing whether the given address is whitelisted.
    */
    function isWhitelistedBetaDelegate(address _addr) public view returns (bool) {
        return betaDelegateWhitelist[_addr];
    }

    /**
     * @dev Sets a new betaDelegate whitelister.
     * @param _newWhitelister The address allowed to whitelist betaDelegates.
     */
    function setBetaDelegateWhitelister(address _newWhitelister) public {
        require(msg.sender == betaDelegateWhitelister || msg.sender == owner, "only Whitelister or Owner");
        betaDelegateWhitelister = _newWhitelister;
        emit BetaDelegateWhitelisterSet(betaDelegateWhitelister, _newWhitelister);
    }

    modifier onlyBetaDelegateWhitelister() {
        require(msg.sender == betaDelegateWhitelister, "onlyBetaDelegateWhitelister");
        _;
    }

    /**
     * @dev Whitelists an address to allow calling BetaDelegatedTransfer.
     * @param _addr The new address to whitelist.
     */
    function whitelistBetaDelegate(address _addr) public onlyBetaDelegateWhitelister {
        require(!betaDelegateWhitelist[_addr], "delegate already whitelisted");
        betaDelegateWhitelist[_addr] = true;
        emit BetaDelegateWhitelisted(_addr);
    }

    /**
     * @dev Unwhitelists an address to disallow calling BetaDelegatedTransfer.
     * @param _addr The new address to whitelist.
     */
    function unwhitelistBetaDelegate(address _addr) public onlyBetaDelegateWhitelister {
        require(betaDelegateWhitelist[_addr], "delegate not whitelisted");
        betaDelegateWhitelist[_addr] = false;
        emit BetaDelegateUnwhitelisted(_addr);
    }
}

/*

  Copyright 2018 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity 0.4.24;

contract IOwnable {

    function transferOwnership(address newOwner)
        public;
}

contract Ownable is
    IOwnable
{
    address public owner;

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

    modifier onlyOwner() {
        require(
            msg.sender == owner,
            "ONLY_CONTRACT_OWNER"
        );
        _;
    }

    function transferOwnership(address newOwner)
        public
        onlyOwner
    {
        if (newOwner != address(0)) {
            owner = newOwner;
        }
    }
}

contract IAuthorizable is
    IOwnable
{
    /// @dev Authorizes an address.
    /// @param target Address to authorize.
    function addAuthorizedAddress(address target)
        external;

    /// @dev Removes authorizion of an address.
    /// @param target Address to remove authorization from.
    function removeAuthorizedAddress(address target)
        external;

    /// @dev Removes authorizion of an address.
    /// @param target Address to remove authorization from.
    /// @param index Index of target in authorities array.
    function removeAuthorizedAddressAtIndex(
        address target,
        uint256 index
    )
        external;
    
    /// @dev Gets all authorized addresses.
    /// @return Array of authorized addresses.
    function getAuthorizedAddresses()
        external
        view
        returns (address[] memory);
}

contract MAuthorizable is
    IAuthorizable
{
    // Event logged when a new address is authorized.
    event AuthorizedAddressAdded(
        address indexed target,
        address indexed caller
    );

    // Event logged when a currently authorized address is unauthorized.
    event AuthorizedAddressRemoved(
        address indexed target,
        address indexed caller
    );

    /// @dev Only authorized addresses can invoke functions with this modifier.
    modifier onlyAuthorized { revert(); _; }
}

contract MixinAuthorizable is
    Ownable,
    MAuthorizable
{
    /// @dev Only authorized addresses can invoke functions with this modifier.
    modifier onlyAuthorized {
        require(
            authorized[msg.sender],
            "SENDER_NOT_AUTHORIZED"
        );
        _;
    }

    mapping (address => bool) public authorized;
    address[] public authorities;

    /// @dev Authorizes an address.
    /// @param target Address to authorize.
    function addAuthorizedAddress(address target)
        external
        onlyOwner
    {
        require(
            !authorized[target],
            "TARGET_ALREADY_AUTHORIZED"
        );

        authorized[target] = true;
        authorities.push(target);
        emit AuthorizedAddressAdded(target, msg.sender);
    }

    /// @dev Removes authorizion of an address.
    /// @param target Address to remove authorization from.
    function removeAuthorizedAddress(address target)
        external
        onlyOwner
    {
        require(
            authorized[target],
            "TARGET_NOT_AUTHORIZED"
        );

        delete authorized[target];
        for (uint256 i = 0; i < authorities.length; i++) {
            if (authorities[i] == target) {
                authorities[i] = authorities[authorities.length - 1];
                authorities.length -= 1;
                break;
            }
        }
        emit AuthorizedAddressRemoved(target, msg.sender);
    }

    /// @dev Removes authorizion of an address.
    /// @param target Address to remove authorization from.
    /// @param index Index of target in authorities array.
    function removeAuthorizedAddressAtIndex(
        address target,
        uint256 index
    )
        external
        onlyOwner
    {
        require(
            authorized[target],
            "TARGET_NOT_AUTHORIZED"
        );
        require(
            index < authorities.length,
            "INDEX_OUT_OF_BOUNDS"
        );
        require(
            authorities[index] == target,
            "AUTHORIZED_ADDRESS_MISMATCH"
        );

        delete authorized[target];
        authorities[index] = authorities[authorities.length - 1];
        authorities.length -= 1;
        emit AuthorizedAddressRemoved(target, msg.sender);
    }

    /// @dev Gets all authorized addresses.
    /// @return Array of authorized addresses.
    function getAuthorizedAddresses()
        external
        view
        returns (address[] memory)
    {
        return authorities;
    }
}

contract ERC20Proxy is
    MixinAuthorizable
{
    // Id of this proxy.
    bytes4 constant internal PROXY_ID = bytes4(keccak256("ERC20Token(address)"));
    
    // solhint-disable-next-line payable-fallback
    function () 
        external
    {
        assembly {
            // The first 4 bytes of calldata holds the function selector
            let selector := and(calldataload(0), 0xffffffff00000000000000000000000000000000000000000000000000000000)

            // `transferFrom` will be called with the following parameters:
            // assetData Encoded byte array.
            // from Address to transfer asset from.
            // to Address to transfer asset to.
            // amount Amount of asset to transfer.
            // bytes4(keccak256("transferFrom(bytes,address,address,uint256)")) = 0xa85e59e4
            if eq(selector, 0xa85e59e400000000000000000000000000000000000000000000000000000000) {

                // To lookup a value in a mapping, we load from the storage location keccak256(k, p),
                // where k is the key left padded to 32 bytes and p is the storage slot
                let start := mload(64)
                mstore(start, and(caller, 0xffffffffffffffffffffffffffffffffffffffff))
                mstore(add(start, 32), authorized_slot)

                // Revert if authorized[msg.sender] == false
                if iszero(sload(keccak256(start, 64))) {
                    // Revert with `Error("SENDER_NOT_AUTHORIZED")`
                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
                    mstore(64, 0x0000001553454e4445525f4e4f545f415554484f52495a454400000000000000)
                    mstore(96, 0)
                    revert(0, 100)
                }

                // `transferFrom`.
                // The function is marked `external`, so no abi decodeding is done for
                // us. Instead, we expect the `calldata` memory to contain the
                // following:
                //
                // | Area     | Offset | Length  | Contents                            |
                // |----------|--------|---------|-------------------------------------|
                // | Header   | 0      | 4       | function selector                   |
                // | Params   |        | 4 * 32  | function parameters:                |
                // |          | 4      |         |   1. offset to assetData (*)        |
                // |          | 36     |         |   2. from                           |
                // |          | 68     |         |   3. to                             |
                // |          | 100    |         |   4. amount                         |
                // | Data     |        |         | assetData:                          |
                // |          | 132    | 32      | assetData Length                    |
                // |          | 164    | **      | assetData Contents                  |
                //
                // (*): offset is computed from start of function parameters, so offset
                //      by an additional 4 bytes in the calldata.
                //
                // (**): see table below to compute length of assetData Contents
                //
                // WARNING: The ABIv2 specification allows additional padding between
                //          the Params and Data section. This will result in a larger
                //          offset to assetData.

                // Asset data itself is encoded as follows:
                //
                // | Area     | Offset | Length  | Contents                            |
                // |----------|--------|---------|-------------------------------------|
                // | Header   | 0      | 4       | function selector                   |
                // | Params   |        | 1 * 32  | function parameters:                |
                // |          | 4      | 12 + 20 |   1. token address                  |

                // We construct calldata for the `token.transferFrom` ABI.
                // The layout of this calldata is in the table below.
                //
                // | Area     | Offset | Length  | Contents                            |
                // |----------|--------|---------|-------------------------------------|
                // | Header   | 0      | 4       | function selector                   |
                // | Params   |        | 3 * 32  | function parameters:                |
                // |          | 4      |         |   1. from                           |
                // |          | 36     |         |   2. to                             |
                // |          | 68     |         |   3. amount                         |

                /////// Read token address from calldata ///////
                // * The token address is stored in `assetData`.
                //
                // * The "offset to assetData" is stored at offset 4 in the calldata (table 1).
                //   [assetDataOffsetFromParams = calldataload(4)]
                //
                // * Notes that the "offset to assetData" is relative to the "Params" area of calldata;
                //   add 4 bytes to account for the length of the "Header" area (table 1).
                //   [assetDataOffsetFromHeader = assetDataOffsetFromParams + 4]
                //
                // * The "token address" is offset 32+4=36 bytes into "assetData" (tables 1 & 2).
                //   [tokenOffset = assetDataOffsetFromHeader + 36 = calldataload(4) + 4 + 36]
                let token := calldataload(add(calldataload(4), 40))
                
                /////// Setup Header Area ///////
                // This area holds the 4-byte `transferFrom` selector.
                // Any trailing data in transferFromSelector will be
                // overwritten in the next `mstore` call.
                mstore(0, 0x23b872dd00000000000000000000000000000000000000000000000000000000)
                
                /////// Setup Params Area ///////
                // We copy the fields `from`, `to` and `amount` in bulk
                // from our own calldata to the new calldata.
                calldatacopy(4, 36, 96)

                /////// Call `token.transferFrom` using the calldata ///////
                let success := call(
                    gas,            // forward all gas
                    token,          // call address of token contract
                    0,              // don't send any ETH
                    0,              // pointer to start of input
                    100,            // length of input
                    0,              // write output over input
                    32              // output size should be 32 bytes
                )

                /////// Check return data. ///////
                // If there is no return data, we assume the token incorrectly
                // does not return a bool. In this case we expect it to revert
                // on failure, which was handled above.
                // If the token does return data, we require that it is a single
                // nonzero 32 bytes value.
                // So the transfer succeeded if the call succeeded and either
                // returned nothing, or returned a non-zero 32 byte value. 
                success := and(success, or(
                    iszero(returndatasize),
                    and(
                        eq(returndatasize, 32),
                        gt(mload(0), 0)
                    )
                ))
                if success {
                    return(0, 0)
                }
                
                // Revert with `Error("TRANSFER_FAILED")`
                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
                mstore(64, 0x0000000f5452414e534645525f4641494c454400000000000000000000000000)
                mstore(96, 0)
                revert(0, 100)
            }

            // Revert if undefined function is called
            revert(0, 0)
        }
    }

    /// @dev Gets the proxy id associated with the proxy address.
    /// @return Proxy id.
    function getProxyId()
        external
        pure
        returns (bytes4)
    {
        return PROXY_ID;
    }
}