Optimize SafeCast
#576
Merged
Optimize SafeCast
#576
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
hensha256
reviewed
Apr 9, 2024
In the `SafeCast` library, a new function `toUint128` has been added to support casting uint256 to uint128. Accompanying the update, a new fuzz test for `toUint128` is also added to verify the behavior when `toUint128` encounters a potential overflow condition. The test ensures its correct functionality and robustness against edge cases.
Refactor `SafeCast.sol` library using inline assembly for better memory-safe operations. By using inline assembly, the code optimizes casting operations which result in reduced gas usage. These changes affect numerous `.forge-snapshot` files, demonstrating an overall reduction in gas usage across multiple contracts.
shuhuiluo
force-pushed
the
optimize-safecast
branch
from
16181ad to
3cd89aa
Compare
The SafeCast library code has been refactored to increase readability. Specifically, repetition of in-line assembly code has been eliminated in favour of a more abstracted '_revertOverflow()' function. This not only simplifies multiple number casting functions but also helps reducing the bytecode size of the contract subtly.
The new function tests the casting method `toUint128` in the `SafeCast` library. It checks that the casting correctly handles 0, maximum uint128 values, and overflows.
The modification simplifies the SafeCast.sol functions to return types directly rather than using a separate variable. Changes have been made to parameter naming for better understanding. Additionally, an overflow check has been added to the toInt128 function for greater accuracy in casting data types.
snreynolds
reviewed
May 13, 2024
| /// @param x The uint256 to be downcasted | ||
| /// @return The downcasted integer, now type uint160 | ||
| function toUint160(uint256 x) internal pure returns (uint160) { | ||
| if (x >= 1 << 160) _revertOverflow(); |
There was a problem hiding this comment.
technically 1<<160 and 1 << 128 can be constants which may make this even cheaper?
There was a problem hiding this comment.
The compiler would compute it to a constant at compile time. It increases readability imo.
snreynolds
approved these changes
May 14, 2024
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Related Issue
Which issue does this pull request resolve?
Description of changes
In the
SafeCastlibrary, a new functiontoUint128has been added to support casting uint256 to uint128. Accompanying the update, a new fuzz test fortoUint128is also added to verify the behavior whentoUint128encounters a potential overflow condition.Refactor
SafeCast.sollibrary to produce optimal bytecode while keeping inline assembly to a minimal. As a result, the code optimizes casting operations which result in reduced gas usage. These changes affect numerous.forge-snapshotfiles, demonstrating an overall reduction in gas usage across multiple contracts.@Vectorized Thanks for the inspiration in Vectorized/solady#928 and Vectorized/solady#929.