diff options
Diffstat (limited to 'contracts/extensions/contracts/src/BalanceThresholdFilter/MixinExchangeCalldata.sol')
-rw-r--r-- | contracts/extensions/contracts/src/BalanceThresholdFilter/MixinExchangeCalldata.sol | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/contracts/extensions/contracts/src/BalanceThresholdFilter/MixinExchangeCalldata.sol b/contracts/extensions/contracts/src/BalanceThresholdFilter/MixinExchangeCalldata.sol new file mode 100644 index 000000000..f2c0caa57 --- /dev/null +++ b/contracts/extensions/contracts/src/BalanceThresholdFilter/MixinExchangeCalldata.sol @@ -0,0 +1,103 @@ + + /* + + 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/LICENSE2.0 + + 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; + +import "./mixins/MExchangeCalldata.sol"; +import "@0x/contracts-utils/contracts/src/LibAddressArray.sol"; + + +contract MixinExchangeCalldata is + MExchangeCalldata +{ + + using LibAddressArray for address[]; + + /// @dev Emulates the `calldataload` opcode on the embedded Exchange calldata, + /// which is accessed through `signedExchangeTransaction`. + /// @param offset Offset into the Exchange calldata. + /// @return value Corresponding 32 byte value stored at `offset`. + function exchangeCalldataload(uint256 offset) + internal pure + returns (bytes32 value) + { + assembly { + // Pointer to exchange transaction + // 0x04 for calldata selector + // 0x40 to access `signedExchangeTransaction`, which is the third parameter + let exchangeTxPtr := calldataload(0x44) + + // Offset into Exchange calldata + // We compute this by adding 0x24 to the `exchangeTxPtr` computed above. + // 0x04 for calldata selector + // 0x20 for length field of `signedExchangeTransaction` + let exchangeCalldataOffset := add(exchangeTxPtr, add(0x24, offset)) + value := calldataload(exchangeCalldataOffset) + } + return value; + } + + /// @dev Convenience function that skips the 4 byte selector when loading + /// from the embedded Exchange calldata. + /// @param offset Offset into the Exchange calldata (minus the 4 byte selector) + /// @return value Corresponding 32 byte value stored at `offset` + 4. + function loadExchangeData(uint256 offset) + internal pure + returns (bytes32 value) + { + value = exchangeCalldataload(offset + 4); + return value; + } + + /// @dev Extracts the maker address from an order stored in the Exchange calldata + /// (which is embedded in `signedExchangeTransaction`). + /// @param orderParamIndex Index of the order in the Exchange function's signature. + /// @return makerAddress The extracted maker address. + function loadMakerAddressFromOrder(uint256 orderParamIndex) + internal pure + returns (address makerAddress) + { + uint256 orderOffsetInBytes = orderParamIndex * 32; + uint256 orderPtr = uint256(loadExchangeData(orderOffsetInBytes)); + makerAddress = address(loadExchangeData(orderPtr)); + return makerAddress; + } + + /// @dev Extracts the maker addresses from an array of orders stored in the Exchange calldata + /// (which is embedded in `signedExchangeTransaction`). + /// @param orderArrayParamIndex Index of the order array in the Exchange function's signature + /// @return makerAddresses The extracted maker addresses. + function loadMakerAddressesFromOrderArray(uint256 orderArrayParamIndex) + internal pure + returns (address[] makerAddresses) + { + uint256 orderArrayOffsetInBytes = orderArrayParamIndex * 32; + uint256 orderArrayPtr = uint256(loadExchangeData(orderArrayOffsetInBytes)); + uint256 orderArrayLength = uint256(loadExchangeData(orderArrayPtr)); + uint256 orderArrayLengthInBytes = orderArrayLength * 32; + uint256 orderArrayElementPtr = orderArrayPtr + 32; + uint256 orderArrayElementEndPtr = orderArrayElementPtr + orderArrayLengthInBytes; + for (uint orderPtrOffset = orderArrayElementPtr; orderPtrOffset < orderArrayElementEndPtr; orderPtrOffset += 32) { + uint256 orderPtr = uint256(loadExchangeData(orderPtrOffset)); + address makerAddress = address(loadExchangeData(orderPtr + orderArrayElementPtr)); + makerAddresses = makerAddresses.append(makerAddress); + } + return makerAddresses; + } +} |