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Diffstat (limited to 'contracts/exchange-libs/contracts/libs/LibAbiEncoder.sol')
| -rw-r--r-- | contracts/exchange-libs/contracts/libs/LibAbiEncoder.sol | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/contracts/exchange-libs/contracts/libs/LibAbiEncoder.sol b/contracts/exchange-libs/contracts/libs/LibAbiEncoder.sol new file mode 100644 index 000000000..5422bfeec --- /dev/null +++ b/contracts/exchange-libs/contracts/libs/LibAbiEncoder.sol @@ -0,0 +1,215 @@ +/* + + 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; + +import "./LibOrder.sol"; + + +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; + } +} |