<h1 align="center">simd-adler32</h1>
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A SIMD-accelerated Adler-32 hash algorithm implementation.
## Features
- No dependencies
- Support `no_std` (with `default-features = false`)
- Runtime CPU feature detection (when `std` enabled)
- Blazing fast performance on as many targets as possible (currently only x86 and x86_64)
- Default to scalar implementation when simd not available
## Quick start
> Cargo.toml
```toml
[dependencies]
simd-adler32 = "*"
```
> example.rs
```rust
use simd_adler32::Adler32;
let mut adler = Adler32::new();
adler.write(b"rust is pretty cool, man");
let hash = adler.finish();
println!("{}", hash);
// 1921255656
```
## Support
**CPU Features**
| ✅ | `x86`, `x86_64` | avx512 |
| ✅ | `x86`, `x86_64` | avx2 |
| ✅ | `x86`, `x86_64` | ssse3 |
| ✅ | `x86`, `x86_64` | sse2 |
| 🚧 | `arm`, `aarch64` | neon |
| ✅ | `wasm32` | simd128 |
**MSRV** `1.36.0`\*\*
Minimum supported rust version is tested before a new version is published. [**] Feature
`const-generics` needs to disabled to build on rustc versions `<1.51` which can be done
by updating your dependency definition to the following.
> Cargo.toml
```toml
[dependencies]
simd-adler32 = { version "*", default-features = false, features = ["std"] }
```
## Performance
Benchmarks listed display number of randomly generated bytes (10k / 100k) and library
name. Benchmarks sources can be found under the [bench](/bench) directory. Crates used for
comparison are [adler](https://crates.io/crates/adler) and
[adler32](https://crates.io/crates/adler32).
> Windows 10 Pro - Intel i5-8300H @ 2.30GHz
| **10k/simd-adler32** | **212.61 ns** | **43.805 GiB/s** |
| 10k/wuffs | 3843 ns | 2.63 GiB/s\* |
| 10k/adler32 | 4.8084 us | 1.9369 GiB/s |
| 10k/adler | 17.979 us | 530.43 MiB/s |
| ----------------------- | --------------- | ------------------ |
| **100k/simd-adler32** | **2.7951 us** | **33.320 GiB/s** |
| 100k/wuffs | 34733 ns | 2.6814 GiB/s\* |
| 100k/adler32 | 48.488 us | 1.9207 GiB/s |
| 100k/adler | 178.36 us | 534.69 MiB/s |
\* wuffs ran using mingw64/gcc, ran with `wuffs bench -ccompilers=gcc -reps=1 -iterscale=300 std/adler32`.
> MacBookPro16,1 - Intel i9-9880H CPU @ 2.30GHz
| **10k/simd-adler32** | **200.37 ns** | **46.480 GiB/s** |
| 10k/adler32 | 4.1516 us | 2.2433 GiB/s |
| 10k/adler | 10.220 us | 933.15 MiB/s |
| ----------------------- | --------------- | ------------------ |
| **100k/simd-adler32** | **2.3282 us** | **40.003 GiB/s** |
| 100k/adler32 | 41.130 us | 2.2643 GiB/s |
| 100k/adler | 83.776 us | 534.69 MiB/s |
## Safety
This crate contains a significant amount of `unsafe` code due to the requirement of `unsafe`
for simd intrinsics. Fuzzing is done on release and debug builds prior to publishing via
`afl`. Fuzzy tests can be found under [fuzz](/fuzz) the directory.
## Resources
- [LICENSE](./LICENSE.md) - MIT
- [CHANGELOG](./CHANGELOG.md)
## Credits
Thank you to the contributors of the following projects.
- [adler](https://github.com/jonas-schievink/adler)
- [adler32](https://github.com/remram44/adler32-rs)
- [crc32fast](https://github.com/srijs/rust-crc32fast)
- [wuffs](https://github.com/google/wuffs)
- [chromium](https://bugs.chromium.org/p/chromium/issues/detail?id=762564)
- [zlib](https://zlib.net/)
## Contributing
Feel free to submit a issue or pull request. :smile: