diff options
Diffstat (limited to 'packages/contracts/src/contracts/current/utils/LibMem/LibMem.sol')
| -rw-r--r-- | packages/contracts/src/contracts/current/utils/LibMem/LibMem.sol | 142 |
1 files changed, 0 insertions, 142 deletions
diff --git a/packages/contracts/src/contracts/current/utils/LibMem/LibMem.sol b/packages/contracts/src/contracts/current/utils/LibMem/LibMem.sol deleted file mode 100644 index 97fb5fb0f..000000000 --- a/packages/contracts/src/contracts/current/utils/LibMem/LibMem.sol +++ /dev/null @@ -1,142 +0,0 @@ -/* - - 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 LibMem -{ - - /// @dev Gets the memory address for a byte array. - /// @param input Byte array to lookup. - /// @return memoryAddress Memory address of byte array. - function getMemAddress(bytes memory input) - internal - pure - returns (uint256 memoryAddress) - { - assembly { - memoryAddress := input - } - 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. - 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. - for {} slt(dest, dEnd) {} { - mstore(dEnd, mload(sEnd)) - sEnd := sub(sEnd, 32) - dEnd := sub(dEnd, 32) - } - - // Write the first 32 bytes - mstore(dest, first) - } - } - } - } -} |