This is a CRC algorithm generator with SIMD support. Apart from the generator, contains the cargo roots for all generated CRC algorithms.
The gen_crates.sh generates all the specific CRC algorithm crates using the
template directory crc-crate-template based on the algorithm list in
algos.csv.
The generated lib.rs file contains a single expression crc!(...) and a
dependency on the crc-fast-gen crate which contains the proc macro logic.
In this example, make some change to the template Cargo.toml file and re-
generate the crates.
~/crc-fast-rs $ vim crc-crate-template/Cargo.toml
(make changes and save)
~/crc-fast-rs $ ./gen_crates.sh
~/crc-fast-rs $ git diff
When the general version is bumped, the crates have to be re-generated.
~/crc-fast-rs $ echo 'v0.2.1' > version.txt
~/crc-fast-rs $ ./gen_crates.sh
In general, the crates are in sync with the version of this repository. For hotfixes to individual crates, patch versions may be applied to only the affected crate(s). If so, the next bump of the general repository will skip those versions for clarity.
The general repository versions is typically bumped on changes to the generating logic. It is stored in version.txt used in the generation of the crates.
Performance is the main raison d'être of this project. Therefore there are plenty of benchmarks of the CRC algorithms.
Each CRC implementation is benchmarked for SIMD, table lookup, and simple loop peformance using criterion. Input size in bytes range from 128 to 64k in powers of 2.
In the future (TODO), the benchmarks will be run on a set of architectures/families and the results published.
~/crc-fast-rs $ cargo bench
Why one crate per algorithm and not just one crate?
- In general, granular crates are preferred in the Rust ecosystem.
- From a consumer point of view, it's unlikely you'll need more than 1 or 2 CRCs for a given application. Explicit crates per algorithm makes it clearer which one you're depending on.
- It makes it possible to pre-expand the code (in the future, WIP) without bloating a single crate (making it slow to download, among other things). Pre-expanding will also improve compilation times.
- It's easier to review the expanded code of a single algorithm for e.g. security compared to the complicated macro.
- It's easier to hotfix if there is a problem with a single algorithm
- Better statistics on CRC populatity, that can guide future development
Everything is licensed under the MIT license (see LICENSE).
- https://reveng.sourceforge.io/crc-catalogue/ good collection of CRC:s with all the relevant parameters
- https://crccalc.com/ used to double-check some values