diff options
| -rw-r--r-- | packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol b/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol index d824449a2..58ce31c70 100644 --- a/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol +++ b/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol @@ -28,6 +28,8 @@ library LibBytes { string constant GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED = "GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED"; string constant GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED = "GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED"; string constant GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED = "GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED"; + string constant FROM_LESS_THAN_TO_REQUIRED = "FROM_LESS_THAN_TO_REQUIRED"; + string constant TO_LESS_THAN_LENGTH_REQUIRED = "TO_LESS_THAN_LENGTH_REQUIRED"; /// @dev Gets the memory address for a byte array. /// @param input Byte array to lookup. @@ -163,6 +165,50 @@ library LibBytes { } } } + + /// @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 slices 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 it's 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. |