Exchange refactor using mixin pattern

11 files changed, 873 insertions, 578 deletions

diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol b/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol
index 33e4a453b..9c6883ebf 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol
@@ -18,587 +18,25 @@
 
 pragma solidity ^0.4.19;
 
-import { ITokenTransferProxy } from "../TokenTransferProxy/ITokenTransferProxy.sol";
-import { IToken } from "../../tokens/Token/IToken.sol";
-import { SafeMath } from "../../utils/SafeMath/SafeMath.sol";
-
-/// @title Exchange - Facilitates exchange of ERC20 tokens.
-/// @author Amir Bandeali - <amir@0xProject.com>, Will Warren - <will@0xProject.com>
-contract Exchange is SafeMath {
-
-    // Error Codes
-    enum Errors {
-        ORDER_EXPIRED,                    // Order has already expired
-        ORDER_FULLY_FILLED_OR_CANCELLED,  // Order has already been fully filled or cancelled
-        ROUNDING_ERROR_TOO_LARGE,         // Rounding error too large
-        INSUFFICIENT_BALANCE_OR_ALLOWANCE // Insufficient balance or allowance for token transfer
-    }
-
-    string constant public VERSION = "1.0.0";
-    uint16 constant public EXTERNAL_QUERY_GAS_LIMIT = 4999;    // Changes to state require at least 5000 gas
-
-    address public ZRX_TOKEN_CONTRACT;
-    address public TOKEN_TRANSFER_PROXY_CONTRACT;
-
-    // Mappings of orderHash => amounts of takerTokenAmount filled or cancelled.
-    mapping (bytes32 => uint) public filled;
-    mapping (bytes32 => uint) public cancelled;
-
-    event LogFill(
-        address indexed maker,
-        address taker,
-        address indexed feeRecipient,
-        address makerToken,
-        address takerToken,
-        uint filledMakerTokenAmount,
-        uint filledTakerTokenAmount,
-        uint paidMakerFee,
-        uint paidTakerFee,
-        bytes32 indexed tokens, // keccak256(makerToken, takerToken), allows subscribing to a token pair
-        bytes32 orderHash
-    );
-
-    event LogCancel(
-        address indexed maker,
-        address indexed feeRecipient,
-        address makerToken,
-        address takerToken,
-        uint cancelledMakerTokenAmount,
-        uint cancelledTakerTokenAmount,
-        bytes32 indexed tokens,
-        bytes32 orderHash
-    );
-
-    event LogError(uint8 indexed errorId, bytes32 indexed orderHash);
-
-    struct Order {
-        address maker;
-        address taker;
-        address makerToken;
-        address takerToken;
-        address feeRecipient;
-        uint makerTokenAmount;
-        uint takerTokenAmount;
-        uint makerFee;
-        uint takerFee;
-        uint expirationTimestampInSec;
-        bytes32 orderHash;
-    }
+import "./MixinExchangeCore.sol";
+import "./MixinSignatureValidatorEcrecover.sol";
+import "./MixinSettlementProxy.sol";
+import "./MixinWrapperFunctions.sol";
+
+contract Exchange is
+    MixinExchangeCore,
+    MixinSignatureValidatorEcrecover,
+    MixinSettlementProxy,
+    MixinWrapperFunctions
+{
+    string constant public VERSION = "2.0.0-alpha";
 
     function Exchange(address _zrxToken, address _tokenTransferProxy)
         public
+        MixinExchangeCore(_zrxToken)
+        MixinSignatureValidatorEcrecover()
+        MixinSettlementProxy(_tokenTransferProxy, _zrxToken)
+        MixinWrapperFunctions()
     {
-        ZRX_TOKEN_CONTRACT = _zrxToken;
-        TOKEN_TRANSFER_PROXY_CONTRACT = _tokenTransferProxy;
-    }
-
-    /*
-    * Core exchange functions
-    */
-
-    /// @dev Fills the input order.
-    /// @param orderAddresses Array of order's maker, taker, makerToken, takerToken, and feeRecipient.
-    /// @param orderValues Array of order's makerTokenAmount, takerTokenAmount, makerFee, takerFee, expirationTimestampInSec, and salt.
-    /// @param fillTakerTokenAmount Desired amount of takerToken to fill.
-    /// @param shouldThrowOnInsufficientBalanceOrAllowance Test if transfer will fail before attempting.
-    /// @param v ECDSA signature parameter v.
-    /// @param r ECDSA signature parameters r.
-    /// @param s ECDSA signature parameters s.
-    /// @return Total amount of takerToken filled in trade.
-    function fillOrder(
-          address[5] orderAddresses,
-          uint[6] orderValues,
-          uint fillTakerTokenAmount,
-          bool shouldThrowOnInsufficientBalanceOrAllowance,
-          uint8 v,
-          bytes32 r,
-          bytes32 s)
-          public
-          returns (uint filledTakerTokenAmount)
-    {
-        Order memory order = Order({
-            maker: orderAddresses[0],
-            taker: orderAddresses[1],
-            makerToken: orderAddresses[2],
-            takerToken: orderAddresses[3],
-            feeRecipient: orderAddresses[4],
-            makerTokenAmount: orderValues[0],
-            takerTokenAmount: orderValues[1],
-            makerFee: orderValues[2],
-            takerFee: orderValues[3],
-            expirationTimestampInSec: orderValues[4],
-            orderHash: getOrderHash(orderAddresses, orderValues)
-        });
-
-        require(order.taker == address(0) || order.taker == msg.sender);
-        require(order.makerTokenAmount > 0 && order.takerTokenAmount > 0 && fillTakerTokenAmount > 0);
-        require(isValidSignature(
-            order.maker,
-            order.orderHash,
-            v,
-            r,
-            s
-        ));
-
-        if (block.timestamp >= order.expirationTimestampInSec) {
-            LogError(uint8(Errors.ORDER_EXPIRED), order.orderHash);
-            return 0;
-        }
-
-        uint remainingTakerTokenAmount = safeSub(order.takerTokenAmount, getUnavailableTakerTokenAmount(order.orderHash));
-        filledTakerTokenAmount = min256(fillTakerTokenAmount, remainingTakerTokenAmount);
-        if (filledTakerTokenAmount == 0) {
-            LogError(uint8(Errors.ORDER_FULLY_FILLED_OR_CANCELLED), order.orderHash);
-            return 0;
-        }
-
-        if (isRoundingError(filledTakerTokenAmount, order.takerTokenAmount, order.makerTokenAmount)) {
-            LogError(uint8(Errors.ROUNDING_ERROR_TOO_LARGE), order.orderHash);
-            return 0;
-        }
-
-        if (!shouldThrowOnInsufficientBalanceOrAllowance && !isTransferable(order, filledTakerTokenAmount)) {
-            LogError(uint8(Errors.INSUFFICIENT_BALANCE_OR_ALLOWANCE), order.orderHash);
-            return 0;
-        }
-
-        uint filledMakerTokenAmount = getPartialAmount(filledTakerTokenAmount, order.takerTokenAmount, order.makerTokenAmount);
-        uint paidMakerFee;
-        uint paidTakerFee;
-        filled[order.orderHash] = safeAdd(filled[order.orderHash], filledTakerTokenAmount);
-        require(transferViaTokenTransferProxy(
-            order.makerToken,
-            order.maker,
-            msg.sender,
-            filledMakerTokenAmount
-        ));
-        require(transferViaTokenTransferProxy(
-            order.takerToken,
-            msg.sender,
-            order.maker,
-            filledTakerTokenAmount
-        ));
-        if (order.feeRecipient != address(0)) {
-            if (order.makerFee > 0) {
-                paidMakerFee = getPartialAmount(filledTakerTokenAmount, order.takerTokenAmount, order.makerFee);
-                require(transferViaTokenTransferProxy(
-                    ZRX_TOKEN_CONTRACT,
-                    order.maker,
-                    order.feeRecipient,
-                    paidMakerFee
-                ));
-            }
-            if (order.takerFee > 0) {
-                paidTakerFee = getPartialAmount(filledTakerTokenAmount, order.takerTokenAmount, order.takerFee);
-                require(transferViaTokenTransferProxy(
-                    ZRX_TOKEN_CONTRACT,
-                    msg.sender,
-                    order.feeRecipient,
-                    paidTakerFee
-                ));
-            }
-        }
-
-        LogFill(
-            order.maker,
-            msg.sender,
-            order.feeRecipient,
-            order.makerToken,
-            order.takerToken,
-            filledMakerTokenAmount,
-            filledTakerTokenAmount,
-            paidMakerFee,
-            paidTakerFee,
-            keccak256(order.makerToken, order.takerToken),
-            order.orderHash
-        );
-        return filledTakerTokenAmount;
-    }
-
-    /// @dev Cancels the input order.
-    /// @param orderAddresses Array of order's maker, taker, makerToken, takerToken, and feeRecipient.
-    /// @param orderValues Array of order's makerTokenAmount, takerTokenAmount, makerFee, takerFee, expirationTimestampInSec, and salt.
-    /// @param cancelTakerTokenAmount Desired amount of takerToken to cancel in order.
-    /// @return Amount of takerToken cancelled.
-    function cancelOrder(
-        address[5] orderAddresses,
-        uint[6] orderValues,
-        uint cancelTakerTokenAmount)
-        public
-        returns (uint)
-    {
-        Order memory order = Order({
-            maker: orderAddresses[0],
-            taker: orderAddresses[1],
-            makerToken: orderAddresses[2],
-            takerToken: orderAddresses[3],
-            feeRecipient: orderAddresses[4],
-            makerTokenAmount: orderValues[0],
-            takerTokenAmount: orderValues[1],
-            makerFee: orderValues[2],
-            takerFee: orderValues[3],
-            expirationTimestampInSec: orderValues[4],
-            orderHash: getOrderHash(orderAddresses, orderValues)
-        });
-
-        require(order.maker == msg.sender);
-        require(order.makerTokenAmount > 0 && order.takerTokenAmount > 0 && cancelTakerTokenAmount > 0);
-
-        if (block.timestamp >= order.expirationTimestampInSec) {
-            LogError(uint8(Errors.ORDER_EXPIRED), order.orderHash);
-            return 0;
-        }
-
-        uint remainingTakerTokenAmount = safeSub(order.takerTokenAmount, getUnavailableTakerTokenAmount(order.orderHash));
-        uint cancelledTakerTokenAmount = min256(cancelTakerTokenAmount, remainingTakerTokenAmount);
-        if (cancelledTakerTokenAmount == 0) {
-            LogError(uint8(Errors.ORDER_FULLY_FILLED_OR_CANCELLED), order.orderHash);
-            return 0;
-        }
-
-        cancelled[order.orderHash] = safeAdd(cancelled[order.orderHash], cancelledTakerTokenAmount);
-
-        LogCancel(
-            order.maker,
-            order.feeRecipient,
-            order.makerToken,
-            order.takerToken,
-            getPartialAmount(cancelledTakerTokenAmount, order.takerTokenAmount, order.makerTokenAmount),
-            cancelledTakerTokenAmount,
-            keccak256(order.makerToken, order.takerToken),
-            order.orderHash
-        );
-        return cancelledTakerTokenAmount;
-    }
-
-    /*
-    * Wrapper functions
-    */
-
-    /// @dev Fills an order with specified parameters and ECDSA signature, throws if specified amount not filled entirely.
-    /// @param orderAddresses Array of order's maker, taker, makerToken, takerToken, and feeRecipient.
-    /// @param orderValues Array of order's makerTokenAmount, takerTokenAmount, makerFee, takerFee, expirationTimestampInSec, and salt.
-    /// @param fillTakerTokenAmount Desired amount of takerToken to fill.
-    /// @param v ECDSA signature parameter v.
-    /// @param r ECDSA signature parameters r.
-    /// @param s ECDSA signature parameters s.
-    function fillOrKillOrder(
-        address[5] orderAddresses,
-        uint[6] orderValues,
-        uint fillTakerTokenAmount,
-        uint8 v,
-        bytes32 r,
-        bytes32 s)
-        public
-    {
-        require(fillOrder(
-            orderAddresses,
-            orderValues,
-            fillTakerTokenAmount,
-            false,
-            v,
-            r,
-            s
-        ) == fillTakerTokenAmount);
-    }
-
-    /// @dev Synchronously executes multiple fill orders in a single transaction.
-    /// @param orderAddresses Array of address arrays containing individual order addresses.
-    /// @param orderValues Array of uint arrays containing individual order values.
-    /// @param fillTakerTokenAmounts Array of desired amounts of takerToken to fill in orders.
-    /// @param shouldThrowOnInsufficientBalanceOrAllowance Test if transfers will fail before attempting.
-    /// @param v Array ECDSA signature v parameters.
-    /// @param r Array of ECDSA signature r parameters.
-    /// @param s Array of ECDSA signature s parameters.
-    function batchFillOrders(
-        address[5][] orderAddresses,
-        uint[6][] orderValues,
-        uint[] fillTakerTokenAmounts,
-        bool shouldThrowOnInsufficientBalanceOrAllowance,
-        uint8[] v,
-        bytes32[] r,
-        bytes32[] s)
-        public
-    {
-        for (uint i = 0; i < orderAddresses.length; i++) {
-            fillOrder(
-                orderAddresses[i],
-                orderValues[i],
-                fillTakerTokenAmounts[i],
-                shouldThrowOnInsufficientBalanceOrAllowance,
-                v[i],
-                r[i],
-                s[i]
-            );
-        }
-    }
-
-    /// @dev Synchronously executes multiple fillOrKill orders in a single transaction.
-    /// @param orderAddresses Array of address arrays containing individual order addresses.
-    /// @param orderValues Array of uint arrays containing individual order values.
-    /// @param fillTakerTokenAmounts Array of desired amounts of takerToken to fill in orders.
-    /// @param v Array ECDSA signature v parameters.
-    /// @param r Array of ECDSA signature r parameters.
-    /// @param s Array of ECDSA signature s parameters.
-    function batchFillOrKillOrders(
-        address[5][] orderAddresses,
-        uint[6][] orderValues,
-        uint[] fillTakerTokenAmounts,
-        uint8[] v,
-        bytes32[] r,
-        bytes32[] s)
-        public
-    {
-        for (uint i = 0; i < orderAddresses.length; i++) {
-            fillOrKillOrder(
-                orderAddresses[i],
-                orderValues[i],
-                fillTakerTokenAmounts[i],
-                v[i],
-                r[i],
-                s[i]
-            );
-        }
-    }
-
-    /// @dev Synchronously executes multiple fill orders in a single transaction until total fillTakerTokenAmount filled.
-    /// @param orderAddresses Array of address arrays containing individual order addresses.
-    /// @param orderValues Array of uint arrays containing individual order values.
-    /// @param fillTakerTokenAmount Desired total amount of takerToken to fill in orders.
-    /// @param shouldThrowOnInsufficientBalanceOrAllowance Test if transfers will fail before attempting.
-    /// @param v Array ECDSA signature v parameters.
-    /// @param r Array of ECDSA signature r parameters.
-    /// @param s Array of ECDSA signature s parameters.
-    /// @return Total amount of fillTakerTokenAmount filled in orders.
-    function fillOrdersUpTo(
-        address[5][] orderAddresses,
-        uint[6][] orderValues,
-        uint fillTakerTokenAmount,
-        bool shouldThrowOnInsufficientBalanceOrAllowance,
-        uint8[] v,
-        bytes32[] r,
-        bytes32[] s)
-        public
-        returns (uint)
-    {
-        uint filledTakerTokenAmount = 0;
-        for (uint i = 0; i < orderAddresses.length; i++) {
-            require(orderAddresses[i][3] == orderAddresses[0][3]); // takerToken must be the same for each order
-            filledTakerTokenAmount = safeAdd(filledTakerTokenAmount, fillOrder(
-                orderAddresses[i],
-                orderValues[i],
-                safeSub(fillTakerTokenAmount, filledTakerTokenAmount),
-                shouldThrowOnInsufficientBalanceOrAllowance,
-                v[i],
-                r[i],
-                s[i]
-            ));
-            if (filledTakerTokenAmount == fillTakerTokenAmount) break;
-        }
-        return filledTakerTokenAmount;
-    }
-
-    /// @dev Synchronously cancels multiple orders in a single transaction.
-    /// @param orderAddresses Array of address arrays containing individual order addresses.
-    /// @param orderValues Array of uint arrays containing individual order values.
-    /// @param cancelTakerTokenAmounts Array of desired amounts of takerToken to cancel in orders.
-    function batchCancelOrders(
-        address[5][] orderAddresses,
-        uint[6][] orderValues,
-        uint[] cancelTakerTokenAmounts)
-        public
-    {
-        for (uint i = 0; i < orderAddresses.length; i++) {
-            cancelOrder(
-                orderAddresses[i],
-                orderValues[i],
-                cancelTakerTokenAmounts[i]
-            );
-        }
-    }
-
-    /*
-    * Constant public functions
-    */
-
-    /// @dev Calculates Keccak-256 hash of order with specified parameters.
-    /// @param orderAddresses Array of order's maker, taker, makerToken, takerToken, and feeRecipient.
-    /// @param orderValues Array of order's makerTokenAmount, takerTokenAmount, makerFee, takerFee, expirationTimestampInSec, and salt.
-    /// @return Keccak-256 hash of order.
-    function getOrderHash(address[5] orderAddresses, uint[6] orderValues)
-        public
-        constant
-        returns (bytes32)
-    {
-        return keccak256(
-            address(this),
-            orderAddresses[0], // maker
-            orderAddresses[1], // taker
-            orderAddresses[2], // makerToken
-            orderAddresses[3], // takerToken
-            orderAddresses[4], // feeRecipient
-            orderValues[0],    // makerTokenAmount
-            orderValues[1],    // takerTokenAmount
-            orderValues[2],    // makerFee
-            orderValues[3],    // takerFee
-            orderValues[4],    // expirationTimestampInSec
-            orderValues[5]     // salt
-        );
-    }
-
-    /// @dev Verifies that an order signature is valid.
-    /// @param signer address of signer.
-    /// @param hash Signed Keccak-256 hash.
-    /// @param v ECDSA signature parameter v.
-    /// @param r ECDSA signature parameters r.
-    /// @param s ECDSA signature parameters s.
-    /// @return Validity of order signature.
-    function isValidSignature(
-        address signer,
-        bytes32 hash,
-        uint8 v,
-        bytes32 r,
-        bytes32 s)
-        public
-        pure
-        returns (bool)
-    {
-        return signer == ecrecover(
-            keccak256("\x19Ethereum Signed Message:\n32", hash),
-            v,
-            r,
-            s
-        );
-    }
-
-    /// @dev Checks if rounding error > 0.1%.
-    /// @param numerator Numerator.
-    /// @param denominator Denominator.
-    /// @param target Value to multiply with numerator/denominator.
-    /// @return Rounding error is present.
-    function isRoundingError(uint numerator, uint denominator, uint target)
-        public
-        pure
-        returns (bool)
-    {
-        uint remainder = mulmod(target, numerator, denominator);
-        if (remainder == 0) return false; // No rounding error.
-
-        uint errPercentageTimes1000000 = safeDiv(
-            safeMul(remainder, 1000000),
-            safeMul(numerator, target)
-        );
-        return errPercentageTimes1000000 > 1000;
-    }
-
-    /// @dev Calculates partial value given a numerator and denominator.
-    /// @param numerator Numerator.
-    /// @param denominator Denominator.
-    /// @param target Value to calculate partial of.
-    /// @return Partial value of target.
-    function getPartialAmount(uint numerator, uint denominator, uint target)
-        public
-        pure
-        returns (uint)
-    {
-        return safeDiv(safeMul(numerator, target), denominator);
-    }
-
-    /// @dev Calculates the sum of values already filled and cancelled for a given order.
-    /// @param orderHash The Keccak-256 hash of the given order.
-    /// @return Sum of values already filled and cancelled.
-    function getUnavailableTakerTokenAmount(bytes32 orderHash)
-        public
-        constant
-        returns (uint)
-    {
-        return safeAdd(filled[orderHash], cancelled[orderHash]);
-    }
-
-
-    /*
-    * Internal functions
-    */
-
-    /// @dev Transfers a token using TokenTransferProxy transferFrom function.
-    /// @param token Address of token to transferFrom.
-    /// @param from Address transfering token.
-    /// @param to Address receiving token.
-    /// @param value Amount of token to transfer.
-    /// @return Success of token transfer.
-    function transferViaTokenTransferProxy(
-        address token,
-        address from,
-        address to,
-        uint value)
-        internal
-        returns (bool)
-    {
-        return ITokenTransferProxy(TOKEN_TRANSFER_PROXY_CONTRACT).transferFrom(token, from, to, value);
-    }
-
-    /// @dev Checks if any order transfers will fail.
-    /// @param order Order struct of params that will be checked.
-    /// @param fillTakerTokenAmount Desired amount of takerToken to fill.
-    /// @return Predicted result of transfers.
-    function isTransferable(Order order, uint fillTakerTokenAmount)
-        internal
-        constant  // The called token contracts may attempt to change state, but will not be able to due to gas limits on getBalance and getAllowance.
-        returns (bool)
-    {
-        address taker = msg.sender;
-        uint fillMakerTokenAmount = getPartialAmount(fillTakerTokenAmount, order.takerTokenAmount, order.makerTokenAmount);
-
-        if (order.feeRecipient != address(0)) {
-            bool isMakerTokenZRX = order.makerToken == ZRX_TOKEN_CONTRACT;
-            bool isTakerTokenZRX = order.takerToken == ZRX_TOKEN_CONTRACT;
-            uint paidMakerFee = getPartialAmount(fillTakerTokenAmount, order.takerTokenAmount, order.makerFee);
-            uint paidTakerFee = getPartialAmount(fillTakerTokenAmount, order.takerTokenAmount, order.takerFee);
-            uint requiredMakerZRX = isMakerTokenZRX ? safeAdd(fillMakerTokenAmount, paidMakerFee) : paidMakerFee;
-            uint requiredTakerZRX = isTakerTokenZRX ? safeAdd(fillTakerTokenAmount, paidTakerFee) : paidTakerFee;
-
-            if (   getBalance(ZRX_TOKEN_CONTRACT, order.maker) < requiredMakerZRX
-                || getAllowance(ZRX_TOKEN_CONTRACT, order.maker) < requiredMakerZRX
-                || getBalance(ZRX_TOKEN_CONTRACT, taker) < requiredTakerZRX
-                || getAllowance(ZRX_TOKEN_CONTRACT, taker) < requiredTakerZRX
-            ) return false;
-
-            if (!isMakerTokenZRX && (   getBalance(order.makerToken, order.maker) < fillMakerTokenAmount // Don't double check makerToken if ZRX
-                                     || getAllowance(order.makerToken, order.maker) < fillMakerTokenAmount)
-            ) return false;
-            if (!isTakerTokenZRX && (   getBalance(order.takerToken, taker) < fillTakerTokenAmount // Don't double check takerToken if ZRX
-                                     || getAllowance(order.takerToken, taker) < fillTakerTokenAmount)
-            ) return false;
-        } else if (   getBalance(order.makerToken, order.maker) < fillMakerTokenAmount
-                   || getAllowance(order.makerToken, order.maker) < fillMakerTokenAmount
-                   || getBalance(order.takerToken, taker) < fillTakerTokenAmount
-                   || getAllowance(order.takerToken, taker) < fillTakerTokenAmount
-        ) return false;
-
-        return true;
-    }
-
-    /// @dev Get token balance of an address.
-    /// @param token Address of token.
-    /// @param owner Address of owner.
-    /// @return Token balance of owner.
-    function getBalance(address token, address owner)
-        internal
-        constant  // The called token contract may attempt to change state, but will not be able to due to an added gas limit.
-        returns (uint)
-    {
-        return IToken(token).balanceOf.gas(EXTERNAL_QUERY_GAS_LIMIT)(owner); // Limit gas to prevent reentrancy
-    }
-
-    /// @dev Get allowance of token given to TokenTransferProxy by an address.
-    /// @param token Address of token.
-    /// @param owner Address of owner.
-    /// @return Allowance of token given to TokenTransferProxy by owner.
-    function getAllowance(address token, address owner)
-        internal
-        constant  // The called token contract may attempt to change state, but will not be able to due to an added gas limit.
-        returns (uint)
-    {
-        return IToken(token).allowance.gas(EXTERNAL_QUERY_GAS_LIMIT)(owner, TOKEN_TRANSFER_PROXY_CONTRACT); // Limit gas to prevent reentrancy
     }
 }
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/LibErrors.sol b/packages/contracts/src/contracts/current/protocol/Exchange/LibErrors.sol
new file mode 100644
index 000000000..380400b27
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/LibErrors.sol
@@ -0,0 +1,33 @@
+/*
+
+  Copyright 2017 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 ^0.4.19;
+
+contract LibErrors {
+  
+    // Error Codes
+    enum Errors {
+        ORDER_EXPIRED,                    // Order has already expired
+        ORDER_FULLY_FILLED_OR_CANCELLED,  // Order has already been fully filled or cancelled
+        ROUNDING_ERROR_TOO_LARGE,         // Rounding error too large
+        INSUFFICIENT_BALANCE_OR_ALLOWANCE // Insufficient balance or allowance for token transfer
+    }
+    
+    event LogError(uint8 indexed errorId, bytes32 indexed orderHash);
+
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/LibOrder.sol b/packages/contracts/src/contracts/current/protocol/Exchange/LibOrder.sol
new file mode 100644
index 000000000..8f87d05a4
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/LibOrder.sol
@@ -0,0 +1,60 @@
+/*
+
+  Copyright 2017 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 ^0.4.19;
+
+contract LibOrder {
+
+    struct Order {
+        address maker;
+        address taker;
+        address makerToken;
+        address takerToken;
+        address feeRecipient;
+        uint makerTokenAmount;
+        uint takerTokenAmount;
+        uint makerFee;
+        uint takerFee;
+        uint expirationTimestampInSec;
+        bytes32 orderHash;
+    }
+
+    /// @dev Calculates Keccak-256 hash of order with specified parameters.
+    /// @param orderAddresses Array of order's maker, taker, makerToken, takerToken, and feeRecipient.
+    /// @param orderValues Array of order's makerTokenAmount, takerTokenAmount, makerFee, takerFee, expirationTimestampInSec, and salt.
+    /// @return Keccak-256 hash of order.
+    function getOrderHash(address[5] orderAddresses, uint[6] orderValues)
+        public view
+        returns (bytes32)
+    {
+        return keccak256(
+            address(this),
+            orderAddresses[0], // maker
+            orderAddresses[1], // taker
+            orderAddresses[2], // makerToken
+            orderAddresses[3], // takerToken
+            orderAddresses[4], // feeRecipient
+            orderValues[0],    // makerTokenAmount
+            orderValues[1],    // takerTokenAmount
+            orderValues[2],    // makerFee
+            orderValues[3],    // takerFee
+            orderValues[4],    // expirationTimestampInSec
+            orderValues[5]     // salt
+        );
+    }
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/LibPartialAmount.sol b/packages/contracts/src/contracts/current/protocol/Exchange/LibPartialAmount.sol
new file mode 100644
index 000000000..3dcae8341
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/LibPartialAmount.sol
@@ -0,0 +1,38 @@
+/*
+
+  Copyright 2017 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 ^0.4.19;
+
+import { SafeMath } from "../../utils/SafeMath/SafeMath.sol";
+
+contract LibPartialAmount is SafeMath {
+  
+    /// @dev Calculates partial value given a numerator and denominator.
+    /// @param numerator Numerator.
+    /// @param denominator Denominator.
+    /// @param target Value to calculate partial of.
+    /// @return Partial value of target.
+    function getPartialAmount(uint numerator, uint denominator, uint target)
+        public pure
+        returns (uint)
+    {
+        return safeDiv(safeMul(numerator, target), denominator);
+    }
+}
+
+
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol
new file mode 100644
index 000000000..fc22f1292
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol
@@ -0,0 +1,287 @@
+/*
+
+  Copyright 2017 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 ^0.4.19;
+
+import "./mixins/MExchangeCore.sol";
+import "./mixins/MSettlement.sol";
+import "./mixins/MSignatureValidator.sol";
+import "./LibOrder.sol";
+import "./LibErrors.sol";
+import "./LibPartialAmount.sol";
+import "../../utils/SafeMath/SafeMath.sol";
+
+/// @dev Provides MExchangeCore
+/// @dev Consumes MSettlement
+/// @dev Consumes MSignatureValidator
+contract MixinExchangeCore is
+    LibOrder,
+    MExchangeCore,
+    MSettlement,
+    MSignatureValidator,
+    SafeMath,
+    LibErrors,
+    LibPartialAmount
+{
+    address public ZRX_TOKEN_CONTRACT;
+
+    // Mappings of orderHash => amounts of takerTokenAmount filled or cancelled.
+    mapping (bytes32 => uint) public filled;
+    mapping (bytes32 => uint) public cancelled;
+    
+    event LogFill(
+        address indexed maker,
+        address taker,
+        address indexed feeRecipient,
+        address makerToken,
+        address takerToken,
+        uint filledMakerTokenAmount,
+        uint filledTakerTokenAmount,
+        uint paidMakerFee,
+        uint paidTakerFee,
+        bytes32 indexed tokens, // keccak256(makerToken, takerToken), allows subscribing to a token pair
+        bytes32 orderHash
+    );
+
+    event LogCancel(
+        address indexed maker,
+        address indexed feeRecipient,
+        address makerToken,
+        address takerToken,
+        uint cancelledMakerTokenAmount,
+        uint cancelledTakerTokenAmount,
+        bytes32 indexed tokens,
+        bytes32 orderHash
+    );
+
+    function MixinExchangeCore(address _zrxToken)
+      public
+    {
+        ZRX_TOKEN_CONTRACT = _zrxToken;
+    }
+
+    /*
+    * Core exchange functions
+    */
+
+    /// @dev Fills the input order.
+    /// @param orderAddresses Array of order's maker, taker, makerToken, takerToken, and feeRecipient.
+    /// @param orderValues Array of order's makerTokenAmount, takerTokenAmount, makerFee, takerFee, expirationTimestampInSec, and salt.
+    /// @param fillTakerTokenAmount Desired amount of takerToken to fill.
+    /// @param shouldThrowOnInsufficientBalanceOrAllowance Test if transfer will fail before attempting.
+    /// @param v ECDSA signature parameter v.
+    /// @param r ECDSA signature parameters r.
+    /// @param s ECDSA signature parameters s.
+    /// @return Total amount of takerToken filled in trade.
+    function fillOrder(
+          address[5] orderAddresses,
+          uint[6] orderValues,
+          uint fillTakerTokenAmount,
+          bool shouldThrowOnInsufficientBalanceOrAllowance,
+          uint8 v,
+          bytes32 r,
+          bytes32 s)
+          public
+          returns (uint filledTakerTokenAmount)
+    {
+        Order memory order = Order({
+            maker: orderAddresses[0],
+            taker: orderAddresses[1],
+            makerToken: orderAddresses[2],
+            takerToken: orderAddresses[3],
+            feeRecipient: orderAddresses[4],
+            makerTokenAmount: orderValues[0],
+            takerTokenAmount: orderValues[1],
+            makerFee: orderValues[2],
+            takerFee: orderValues[3],
+            expirationTimestampInSec: orderValues[4],
+            orderHash: getOrderHash(orderAddresses, orderValues)
+        });
+
+        require(order.taker == address(0) || order.taker == msg.sender);
+        require(order.makerTokenAmount > 0 && order.takerTokenAmount > 0 && fillTakerTokenAmount > 0);
+        require(isValidSignature(
+            order.maker,
+            order.orderHash,
+            v,
+            r,
+            s
+        ));
+
+        if (block.timestamp >= order.expirationTimestampInSec) {
+            LogError(uint8(Errors.ORDER_EXPIRED), order.orderHash);
+            return 0;
+        }
+
+        uint remainingTakerTokenAmount = safeSub(order.takerTokenAmount, getUnavailableTakerTokenAmount(order.orderHash));
+        filledTakerTokenAmount = min256(fillTakerTokenAmount, remainingTakerTokenAmount);
+        if (filledTakerTokenAmount == 0) {
+            LogError(uint8(Errors.ORDER_FULLY_FILLED_OR_CANCELLED), order.orderHash);
+            return 0;
+        }
+
+        if (isRoundingError(filledTakerTokenAmount, order.takerTokenAmount, order.makerTokenAmount)) {
+            LogError(uint8(Errors.ROUNDING_ERROR_TOO_LARGE), order.orderHash);
+            return 0;
+        }
+
+        if (!shouldThrowOnInsufficientBalanceOrAllowance && !isTransferable(order, filledTakerTokenAmount)) {
+            LogError(uint8(Errors.INSUFFICIENT_BALANCE_OR_ALLOWANCE), order.orderHash);
+            return 0;
+        }
+
+        uint filledMakerTokenAmount = getPartialAmount(filledTakerTokenAmount, order.takerTokenAmount, order.makerTokenAmount);
+        uint paidMakerFee;
+        uint paidTakerFee;
+        filled[order.orderHash] = safeAdd(filled[order.orderHash], filledTakerTokenAmount);
+        require(transferViaTokenTransferProxy(
+            order.makerToken,
+            order.maker,
+            msg.sender,
+            filledMakerTokenAmount
+        ));
+        require(transferViaTokenTransferProxy(
+            order.takerToken,
+            msg.sender,
+            order.maker,
+            filledTakerTokenAmount
+        ));
+        if (order.feeRecipient != address(0)) {
+            if (order.makerFee > 0) {
+                paidMakerFee = getPartialAmount(filledTakerTokenAmount, order.takerTokenAmount, order.makerFee);
+                require(transferViaTokenTransferProxy(
+                    ZRX_TOKEN_CONTRACT,
+                    order.maker,
+                    order.feeRecipient,
+                    paidMakerFee
+                ));
+            }
+            if (order.takerFee > 0) {
+                paidTakerFee = getPartialAmount(filledTakerTokenAmount, order.takerTokenAmount, order.takerFee);
+                require(transferViaTokenTransferProxy(
+                    ZRX_TOKEN_CONTRACT,
+                    msg.sender,
+                    order.feeRecipient,
+                    paidTakerFee
+                ));
+            }
+        }
+
+        LogFill(
+            order.maker,
+            msg.sender,
+            order.feeRecipient,
+            order.makerToken,
+            order.takerToken,
+            filledMakerTokenAmount,
+            filledTakerTokenAmount,
+            paidMakerFee,
+            paidTakerFee,
+            keccak256(order.makerToken, order.takerToken),
+            order.orderHash
+        );
+        return filledTakerTokenAmount;
+    }
+
+    /// @dev Cancels the input order.
+    /// @param orderAddresses Array of order's maker, taker, makerToken, takerToken, and feeRecipient.
+    /// @param orderValues Array of order's makerTokenAmount, takerTokenAmount, makerFee, takerFee, expirationTimestampInSec, and salt.
+    /// @param cancelTakerTokenAmount Desired amount of takerToken to cancel in order.
+    /// @return Amount of takerToken cancelled.
+    function cancelOrder(
+        address[5] orderAddresses,
+        uint[6] orderValues,
+        uint cancelTakerTokenAmount)
+        public
+        returns (uint)
+    {
+        Order memory order = Order({
+            maker: orderAddresses[0],
+            taker: orderAddresses[1],
+            makerToken: orderAddresses[2],
+            takerToken: orderAddresses[3],
+            feeRecipient: orderAddresses[4],
+            makerTokenAmount: orderValues[0],
+            takerTokenAmount: orderValues[1],
+            makerFee: orderValues[2],
+            takerFee: orderValues[3],
+            expirationTimestampInSec: orderValues[4],
+            orderHash: getOrderHash(orderAddresses, orderValues)
+        });
+
+        require(order.maker == msg.sender);
+        require(order.makerTokenAmount > 0 && order.takerTokenAmount > 0 && cancelTakerTokenAmount > 0);
+
+        if (block.timestamp >= order.expirationTimestampInSec) {
+            LogError(uint8(Errors.ORDER_EXPIRED), order.orderHash);
+            return 0;
+        }
+
+        uint remainingTakerTokenAmount = safeSub(order.takerTokenAmount, getUnavailableTakerTokenAmount(order.orderHash));
+        uint cancelledTakerTokenAmount = min256(cancelTakerTokenAmount, remainingTakerTokenAmount);
+        if (cancelledTakerTokenAmount == 0) {
+            LogError(uint8(Errors.ORDER_FULLY_FILLED_OR_CANCELLED), order.orderHash);
+            return 0;
+        }
+
+        cancelled[order.orderHash] = safeAdd(cancelled[order.orderHash], cancelledTakerTokenAmount);
+
+        LogCancel(
+            order.maker,
+            order.feeRecipient,
+            order.makerToken,
+            order.takerToken,
+            getPartialAmount(cancelledTakerTokenAmount, order.takerTokenAmount, order.makerTokenAmount),
+            cancelledTakerTokenAmount,
+            keccak256(order.makerToken, order.takerToken),
+            order.orderHash
+        );
+        return cancelledTakerTokenAmount;
+    }
+    
+    /// @dev Checks if rounding error > 0.1%.
+    /// @param numerator Numerator.
+    /// @param denominator Denominator.
+    /// @param target Value to multiply with numerator/denominator.
+    /// @return Rounding error is present.
+    function isRoundingError(uint numerator, uint denominator, uint target)
+        public
+        pure
+        returns (bool)
+    {
+        uint remainder = mulmod(target, numerator, denominator);
+        if (remainder == 0) return false; // No rounding error.
+
+        uint errPercentageTimes1000000 = safeDiv(
+            safeMul(remainder, 1000000),
+            safeMul(numerator, target)
+        );
+        return errPercentageTimes1000000 > 1000;
+    }
+
+    /// @dev Calculates the sum of values already filled and cancelled for a given order.
+    /// @param orderHash The Keccak-256 hash of the given order.
+    /// @return Sum of values already filled and cancelled.
+    function getUnavailableTakerTokenAmount(bytes32 orderHash)
+        public
+        constant
+        returns (uint)
+    {
+        return safeAdd(filled[orderHash], cancelled[orderHash]);
+    }
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSettlementProxy.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinSettlementProxy.sol
new file mode 100644
index 000000000..906020d26
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinSettlementProxy.sol
@@ -0,0 +1,126 @@
+/*
+
+  Copyright 2017 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 ^0.4.19;
+
+import "./mixins/MSettlement.sol";
+import "../TokenTransferProxy/ITokenTransferProxy.sol";
+import "../../tokens/Token/IToken.sol";
+import "./LibPartialAmount.sol";
+
+/// @dev Provides MixinSettlement
+contract MixinSettlementProxy is
+    MSettlement,
+    LibPartialAmount
+{
+
+    uint16 constant public EXTERNAL_QUERY_GAS_LIMIT = 4999;    // Changes to state require at least 5000 gas
+
+    address public TOKEN_TRANSFER_PROXY_CONTRACT;
+    
+    address public ZRX_TOKEN_CONTRACT;
+    
+    function MixinSettlementProxy(address proxyContract, address zrxToken)
+        public
+    {
+      ZRX_TOKEN_CONTRACT = zrxToken;
+      TOKEN_TRANSFER_PROXY_CONTRACT = proxyContract;
+    }
+
+    /// @dev Transfers a token using TokenTransferProxy transferFrom function.
+    /// @param token Address of token to transferFrom.
+    /// @param from Address transfering token.
+    /// @param to Address receiving token.
+    /// @param value Amount of token to transfer.
+    /// @return Success of token transfer.
+    function transferViaTokenTransferProxy(
+        address token,
+        address from,
+        address to,
+        uint value)
+        internal
+        returns (bool)
+    {
+        return ITokenTransferProxy(TOKEN_TRANSFER_PROXY_CONTRACT).transferFrom(token, from, to, value);
+    }
+
+    /// @dev Checks if any order transfers will fail.
+    /// @param order Order struct of params that will be checked.
+    /// @param fillTakerTokenAmount Desired amount of takerToken to fill.
+    /// @return Predicted result of transfers.
+    function isTransferable(Order order, uint fillTakerTokenAmount)
+        internal
+        constant  // The called token contracts may attempt to change state, but will not be able to due to gas limits on getBalance and getAllowance.
+        returns (bool)
+    {
+        address taker = msg.sender;
+        uint fillMakerTokenAmount = getPartialAmount(fillTakerTokenAmount, order.takerTokenAmount, order.makerTokenAmount);
+
+        if (order.feeRecipient != address(0)) {
+            bool isMakerTokenZRX = order.makerToken == ZRX_TOKEN_CONTRACT;
+            bool isTakerTokenZRX = order.takerToken == ZRX_TOKEN_CONTRACT;
+            uint paidMakerFee = getPartialAmount(fillTakerTokenAmount, order.takerTokenAmount, order.makerFee);
+            uint paidTakerFee = getPartialAmount(fillTakerTokenAmount, order.takerTokenAmount, order.takerFee);
+            uint requiredMakerZRX = isMakerTokenZRX ? safeAdd(fillMakerTokenAmount, paidMakerFee) : paidMakerFee;
+            uint requiredTakerZRX = isTakerTokenZRX ? safeAdd(fillTakerTokenAmount, paidTakerFee) : paidTakerFee;
+
+            if (   getBalance(ZRX_TOKEN_CONTRACT, order.maker) < requiredMakerZRX
+                || getAllowance(ZRX_TOKEN_CONTRACT, order.maker) < requiredMakerZRX
+                || getBalance(ZRX_TOKEN_CONTRACT, taker) < requiredTakerZRX
+                || getAllowance(ZRX_TOKEN_CONTRACT, taker) < requiredTakerZRX
+            ) return false;
+
+            if (!isMakerTokenZRX && (   getBalance(order.makerToken, order.maker) < fillMakerTokenAmount // Don't double check makerToken if ZRX
+                                     || getAllowance(order.makerToken, order.maker) < fillMakerTokenAmount)
+            ) return false;
+            if (!isTakerTokenZRX && (   getBalance(order.takerToken, taker) < fillTakerTokenAmount // Don't double check takerToken if ZRX
+                                     || getAllowance(order.takerToken, taker) < fillTakerTokenAmount)
+            ) return false;
+        } else if (   getBalance(order.makerToken, order.maker) < fillMakerTokenAmount
+                   || getAllowance(order.makerToken, order.maker) < fillMakerTokenAmount
+                   || getBalance(order.takerToken, taker) < fillTakerTokenAmount
+                   || getAllowance(order.takerToken, taker) < fillTakerTokenAmount
+        ) return false;
+
+        return true;
+    }
+
+    /// @dev Get token balance of an address.
+    /// @param token Address of token.
+    /// @param owner Address of owner.
+    /// @return Token balance of owner.
+    function getBalance(address token, address owner)
+        internal
+        constant  // The called token contract may attempt to change state, but will not be able to due to an added gas limit.
+        returns (uint)
+    {
+        return IToken(token).balanceOf.gas(EXTERNAL_QUERY_GAS_LIMIT)(owner); // Limit gas to prevent reentrancy
+    }
+
+    /// @dev Get allowance of token given to TokenTransferProxy by an address.
+    /// @param token Address of token.
+    /// @param owner Address of owner.
+    /// @return Allowance of token given to TokenTransferProxy by owner.
+    function getAllowance(address token, address owner)
+        internal
+        constant  // The called token contract may attempt to change state, but will not be able to due to an added gas limit.
+        returns (uint)
+    {
+        return IToken(token).allowance.gas(EXTERNAL_QUERY_GAS_LIMIT)(owner, TOKEN_TRANSFER_PROXY_CONTRACT); // Limit gas to prevent reentrancy
+    }
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidatorEcrecover.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidatorEcrecover.sol
new file mode 100644
index 000000000..08eb15344
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidatorEcrecover.sol
@@ -0,0 +1,44 @@
+/*
+
+  Copyright 2017 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 ^0.4.19;
+
+import "./mixins/MSignatureValidator.sol";
+
+/// @dev Provides MSignatureValidator
+contract MixinSignatureValidatorEcrecover is
+    MSignatureValidator
+{
+    function isValidSignature(
+        address signer,
+        bytes32 hash,
+        uint8 v,
+        bytes32 r,
+        bytes32 s)
+        public
+        constant
+        returns (bool)
+    {
+        return signer == ecrecover(
+            keccak256("\x19Ethereum Signed Message:\n32", hash),
+            v,
+            r,
+            s
+        );
+    }
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol
new file mode 100644
index 000000000..eb1a7b6f5
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol
@@ -0,0 +1,143 @@
+/*
+
+  Copyright 2017 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 ^0.4.19;
+
+import './mixins/MExchangeCore.sol';
+import "../../utils/SafeMath/SafeMath.sol";
+
+/// @dev Consumes MExchangeCore
+contract MixinWrapperFunctions is
+    MExchangeCore,
+    SafeMath
+{
+  
+    /// @dev Fills an order with specified parameters and ECDSA signature, throws if specified amount not filled entirely.
+    /// @param orderAddresses Array of order's maker, taker, makerToken, takerToken, and feeRecipient.
+    /// @param orderValues Array of order's makerTokenAmount, takerTokenAmount, makerFee, takerFee, expirationTimestampInSec, and salt.
+    /// @param fillTakerTokenAmount Desired amount of takerToken to fill.
+    /// @param v ECDSA signature parameter v.
+    /// @param r ECDSA signature parameters r.
+    /// @param s ECDSA signature parameters s.
+    function fillOrKillOrder(
+        address[5] orderAddresses,
+        uint[6] orderValues,
+        uint fillTakerTokenAmount,
+        uint8 v,
+        bytes32 r,
+        bytes32 s)
+        public
+    {
+        require(fillOrder(
+            orderAddresses,
+            orderValues,
+            fillTakerTokenAmount,
+            false,
+            v,
+            r,
+            s
+        ) == fillTakerTokenAmount);
+    }
+
+    function batchFillOrders(
+        address[5][] orderAddresses,
+        uint[6][] orderValues,
+        uint[] fillTakerTokenAmounts,
+        bool shouldThrowOnInsufficientBalanceOrAllowance,
+        uint8[] v,
+        bytes32[] r,
+        bytes32[] s)
+        external
+    {
+        for (uint i = 0; i < orderAddresses.length; i++) {
+            fillOrder(
+                orderAddresses[i],
+                orderValues[i],
+                fillTakerTokenAmounts[i],
+                shouldThrowOnInsufficientBalanceOrAllowance,
+                v[i],
+                r[i],
+                s[i]
+            );
+        }
+    }
+
+    function batchFillOrKillOrders(
+        address[5][] orderAddresses,
+        uint[6][] orderValues,
+        uint[] fillTakerTokenAmounts,
+        uint8[] v,
+        bytes32[] r,
+        bytes32[] s)
+        external
+    {
+        for (uint i = 0; i < orderAddresses.length; i++) {
+            fillOrKillOrder(
+                orderAddresses[i],
+                orderValues[i],
+                fillTakerTokenAmounts[i],
+                v[i],
+                r[i],
+                s[i]
+            );
+        }
+    }
+
+    function fillOrdersUpTo(
+        address[5][] orderAddresses,
+        uint[6][] orderValues,
+        uint fillTakerTokenAmount,
+        bool shouldThrowOnInsufficientBalanceOrAllowance,
+        uint8[] v,
+        bytes32[] r,
+        bytes32[] s)
+        public /// Stack to deep when set to external
+        returns (uint)
+    {
+        uint filledTakerTokenAmount = 0;
+        for (uint i = 0; i < orderAddresses.length; i++) {
+            require(orderAddresses[i][3] == orderAddresses[0][3]); // takerToken must be the same for each order
+            filledTakerTokenAmount = safeAdd(filledTakerTokenAmount, fillOrder(
+                orderAddresses[i],
+                orderValues[i],
+                safeSub(fillTakerTokenAmount, filledTakerTokenAmount),
+                shouldThrowOnInsufficientBalanceOrAllowance,
+                v[i],
+                r[i],
+                s[i]
+            ));
+            if (filledTakerTokenAmount == fillTakerTokenAmount) break;
+        }
+        return filledTakerTokenAmount;
+    }
+
+    function batchCancelOrders(
+        address[5][] orderAddresses,
+        uint[6][] orderValues,
+        uint[] cancelTakerTokenAmounts)
+        external
+    {
+        for (uint i = 0; i < orderAddresses.length; i++) {
+            cancelOrder(
+                orderAddresses[i],
+                orderValues[i],
+                cancelTakerTokenAmounts[i]
+            );
+        }
+    }
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MExchangeCore.sol b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MExchangeCore.sol
new file mode 100644
index 000000000..2525b6930
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MExchangeCore.sol
@@ -0,0 +1,41 @@
+/*
+
+  Copyright 2017 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 ^0.4.19;
+
+contract MExchangeCore {
+    
+    function fillOrder(
+        address[5] orderAddresses,
+        uint[6] orderValues,
+        uint fillTakerTokenAmount,
+        bool shouldThrowOnInsufficientBalanceOrAllowance,
+        uint8 v,
+        bytes32 r,
+        bytes32 s)
+        public
+        returns (uint filledTakerTokenAmount);
+
+    function cancelOrder(
+        address[5] orderAddresses,
+        uint[6] orderValues,
+        uint cancelTakerTokenAmount)
+        public
+        returns (uint);
+
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MSettlement.sol b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MSettlement.sol
new file mode 100644
index 000000000..b6506dfab
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MSettlement.sol
@@ -0,0 +1,47 @@
+/*
+
+  Copyright 2017 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 ^0.4.19;
+
+import "../LibOrder.sol";
+
+contract MSettlement is LibOrder {
+
+    /// @dev Transfers a token using TokenTransferProxy transferFrom function.
+    /// @param token Address of token to transferFrom.
+    /// @param from Address transfering token.
+    /// @param to Address receiving token.
+    /// @param value Amount of token to transfer.
+    /// @return Success of token transfer.
+    function transferViaTokenTransferProxy(
+        address token,
+        address from,
+        address to,
+        uint value)
+        internal
+        returns (bool);
+
+    /// @dev Checks if any order transfers will fail.
+    /// @param order Order struct of params that will be checked.
+    /// @param fillTakerTokenAmount Desired amount of takerToken to fill.
+    /// @return Predicted result of transfers.
+    function isTransferable(Order order, uint fillTakerTokenAmount)
+        internal
+        constant  // The called token contracts may attempt to change state, but will not be able to due to gas limits on getBalance and getAllowance.
+        returns (bool);
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MSignatureValidator.sol b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MSignatureValidator.sol
new file mode 100644
index 000000000..7321db24f
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MSignatureValidator.sol
@@ -0,0 +1,38 @@
+/*
+
+  Copyright 2017 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 ^0.4.19;
+
+contract MSignatureValidator {
+
+    /// @dev Verifies that an order signature is valid.
+    /// @param signer address of signer.
+    /// @param hash Signed Keccak-256 hash.
+    /// @param v ECDSA signature parameter v.
+    /// @param r ECDSA signature parameters r.
+    /// @param s ECDSA signature parameters s.
+    /// @return Validity of order signature.
+    function isValidSignature(
+        address signer,
+        bytes32 hash,
+        uint8 v,
+        bytes32 r,
+        bytes32 s)
+        public view
+        returns (bool);
+}