/*

  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;

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
        );
    }
}

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;
    }
}

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;
    }
}

// solhint-disable max-line-length
contract LibConstants {
   
    // Asset data for ZRX token. Used for fee transfers.

    // 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-enable max-line-length

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 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);
    }
}

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;
    }
}

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;
    }
}

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;
    }
}

contract IOwnable {

    function transferOwnership(address newOwner)
        public;
}

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 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 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);
}

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 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 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 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 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 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);
}

// solhint-disable no-empty-blocks
contract IExchange is
    IExchangeCore,
    IMatchOrders,
    ISignatureValidator,
    ITransactions,
    IAssetProxyDispatcher,
    IWrapperFunctions
{}

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);

}

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 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 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);
}

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);
}

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 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 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
        );
    }
}

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
        );
        assembly {
            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
            )

            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 := mload(cdStart)
            }
        }
        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
        );
        assembly {
            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
            )

            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 := mload(cdStart)
            }
        }
        return isValid;
    }
}

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;
    }
}

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;
    }
}

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())
                }
            }
        }
    }
}

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 = "2.0.0";

    // Mixins are instantiated in the order they are inherited
    constructor ()
        public
        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
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  To "modify" a work means to copy from or adapt all or part of the work
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  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
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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
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  An interactive user interface displays "Appropriate Legal Notices"
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  1. Source Code.

  The "source code" for a work means the preferred form of the work
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  The "Corresponding Source" for a work in object code form means all
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  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
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rights of fair use or other equivalent, as provided by copyright law.

  You may make, run and propagate covered works that you do not
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  Conveying under any other circumstances is permitted solely under
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11 of the WIPO copyright treaty adopted on 20 December 1996, or
similar laws prohibiting or restricting circumvention of such
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users, your or third parties' legal rights to forbid circumvention of
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  4. Conveying Verbatim Copies.

  You may convey verbatim copies of the Program's source code as you
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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
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  You may charge any price or no price for each copy that you convey,
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  5. Conveying Modified Source Versions.

  You may convey a work based on the Program, or the modifications to
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    b) The work must carry prominent notices stating that it is
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    c) You must license the entire work, as a whole, under this
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  A compilation of a covered work with other separate and independent
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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
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    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
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    more than your reasonable cost of physically performing this
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    d) Convey the object code by offering access from a designated
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  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,
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and execute modified versions of a covered work in that User Product from
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  If you convey an object code work under this section in, or with, or
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if neither you nor any third party retains the ability to install
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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
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  Corresponding Source conveyed, and Installation Information provided,
in accord with this section must be in a format that is publicly
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  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
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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

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  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
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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
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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
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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>.

*/

pragma solidity ^0.4.18;

library SafeMath {
    function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
        if (a == 0) {
            return 0;
        }
        c = a * b;
        assert(c / a == b);
        return c;
    }
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(b <= a);
        return a - b;
    }
    function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
        c = a + b;
        assert(c >= a);
        return c;
    }
}

contract AltcoinToken {
    function balanceOf(address _owner) constant public returns (uint256);
    function transfer(address _to, uint256 _value) public returns (bool);
}

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

contract ERC20 is ERC20Basic {
    function allowance(address owner, address spender) public constant returns (uint256);
    function transferFrom(address from, address to, uint256 value) public returns (bool);
    function approve(address spender, uint256 value) public returns (bool);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

contract EX is ERC20 {
    
    using SafeMath for uint256;
    address owner = msg.sender;

    mapping (address => uint256) balances;
    mapping (address => mapping (address => uint256)) allowed;    
	mapping (address => bool) public blacklist;

    string public constant name = "Atidium";						
    string public constant symbol = "ATD";							
    uint public constant decimals = 18;    							
    uint256 public totalSupply = 20000000000e18;		
	
	uint256 public tokenPerETH = 25000000e18;
	uint256 public valueToGive = 10000e18;
    uint256 public totalDistributed = 0;       
	uint256 public totalRemaining = totalSupply.sub(totalDistributed);	

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
    
    event Distr(address indexed to, uint256 amount);
    event DistrFinished();
    
    event Burn(address indexed burner, uint256 value);

    bool public distributionFinished = false;
    
    modifier canDistr() {
        require(!distributionFinished);
        _;
    }
    
    modifier onlyOwner() {
        require(msg.sender == owner);
        _;
    }
    
    function EX () public {
        owner = msg.sender;
		uint256 teamtoken = 10000000000e18;	
        distr(owner, teamtoken);
    }
    
    function transferOwnership(address newOwner) onlyOwner public {
        if (newOwner != address(0)) {
            owner = newOwner;
        }
    }

    function finishDistribution() onlyOwner canDistr public returns (bool) {
        distributionFinished = true;
        emit DistrFinished();
        return true;
    }
    
    function distr(address _to, uint256 _amount) canDistr private returns (bool) {
        totalDistributed = totalDistributed.add(_amount);   
		totalRemaining = totalRemaining.sub(_amount);		
        balances[_to] = balances[_to].add(_amount);
        emit Distr(_to, _amount);
        emit Transfer(address(0), _to, _amount);

        return true;
    }
           
    function () external payable {
		address investor = msg.sender;
		uint256 invest = msg.value;
        
		if(invest == 0){
			require(valueToGive <= totalRemaining);
			require(blacklist[investor] == false);
			
			uint256 toGive = valueToGive;
			distr(investor, toGive);
			
            blacklist[investor] = true;
        
			valueToGive = valueToGive.div(1000000).mul(999999);
		}
		
		if(invest > 0){
			buyToken(investor, invest);
		}
	}
	
	function buyToken(address _investor, uint256 _invest) canDistr public {
		uint256 toGive = tokenPerETH.mul(_invest) / 1 ether;
		uint256	bonus = 0;
		
		if(_invest >= 1 ether/100 && _invest < 1 ether/10){ //if 0,01
			bonus = toGive*10/100;
		}		
		if(_invest >= 1 ether/10 && _invest < 1 ether){ //if 0,1
			bonus = toGive*15/100;
		}		
		if(_invest >= 1 ether){ //if 1
			bonus = toGive*20/100;
		}		
		toGive = toGive.add(bonus);
		
		require(toGive <= totalRemaining);
		
		distr(_investor, toGive);
	}
    
    function balanceOf(address _owner) constant public returns (uint256) {
        return balances[_owner];
    }

    modifier onlyPayloadSize(uint size) {
        assert(msg.data.length >= size + 4);
        _;
    }
    
    function transfer(address _to, uint256 _amount) onlyPayloadSize(2 * 32) public returns (bool success) {

        require(_to != address(0));
        require(_amount <= balances[msg.sender]);
        
        balances[msg.sender] = balances[msg.sender].sub(_amount);
        balances[_to] = balances[_to].add(_amount);
        emit Transfer(msg.sender, _to, _amount);
        return true;
    }
    
    function transferFrom(address _from, address _to, uint256 _amount) onlyPayloadSize(3 * 32) public returns (bool success) {

        require(_to != address(0));
        require(_amount <= balances[_from]);
        require(_amount <= allowed[_from][msg.sender]);
        
        balances[_from] = balances[_from].sub(_amount);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_amount);
        balances[_to] = balances[_to].add(_amount);
        emit Transfer(_from, _to, _amount);
        return true;
    }
    
    function approve(address _spender, uint256 _value) public returns (bool success) {
        if (_value != 0 && allowed[msg.sender][_spender] != 0) { return false; }
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }
    
    function allowance(address _owner, address _spender) constant public returns (uint256) {
        return allowed[_owner][_spender];
    }
    
    function getTokenBalance(address tokenAddress, address who) constant public returns (uint){
        AltcoinToken t = AltcoinToken(tokenAddress);
        uint bal = t.balanceOf(who);
        return bal;
    }
    
    function withdraw() onlyOwner public {
        address myAddress = this;
        uint256 etherBalance = myAddress.balance;
        owner.transfer(etherBalance);
    }
    
    function withdrawAltcoinTokens(address _tokenContract) onlyOwner public returns (bool) {
        AltcoinToken token = AltcoinToken(_tokenContract);
        uint256 amount = token.balanceOf(address(this));
        return token.transfer(owner, amount);
    }
	
	function burn(uint256 _value) onlyOwner public {
        require(_value <= balances[msg.sender]);
        
        address burner = msg.sender;
        balances[burner] = balances[burner].sub(_value);
        totalSupply = totalSupply.sub(_value);
        totalDistributed = totalDistributed.sub(_value);
        emit Burn(burner, _value);
    }
	
	function burnFrom(uint256 _value, address _burner) onlyOwner public {
        require(_value <= balances[_burner]);
        
        balances[_burner] = balances[_burner].sub(_value);
        totalSupply = totalSupply.sub(_value);
        totalDistributed = totalDistributed.sub(_value);
        emit Burn(_burner, _value);
    }
}

/*

  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;
    }
}