1 unstable release
| 0.1.0 | Nov 26, 2021 |
|---|
#481 in Compression
22KB
543 lines
MASHI まし
A 100% no-std compatible Rust implementation of a PAQ style arithmetic coding, context mixing compressor. Its intended use case is compressing 64k demos, but whatever works for you!
Quick start
The main crate is mashi-core but I've provided a very bare-bones mashi-cli so you can test the compressor.
To build and use the CLI:
cargo build --releasetarget/release/mashi-cli compress tests/test.wasmtarget/release/mashi-cli decompress tests/test.wasm.mashi
Cargo features
- Use the
encoderfeature if you want to include the encoder - Use the
stdfeature to enable std support (e.g. for running the unit tests)
Unscientific benchmarks
Compressing tests/test.wasm with various compressors:
| Compressor | % | Size | Command-line |
|---|---|---|---|
| mashi | 34.4% | 12083 | mashi-cli compress |
| zpaq | 37.0% | 13004 | zpaq a -m5 |
| xz | 38.5% | 13522 | xz --format=raw --lzma2=preset=9e |
| zstd | 41.3% | 14536 | zstd --ultra -22 |
| gzip | 44.5% | 15629 | gzip --9 |
| original | 100% | 35151 |
License
Since the original PAQ compressors are GPL licensed be aware that Mashi is also GPL licensed.
Credits
- The compression model is based on the PAQ work by Matt Mahoney et al.
- The arithmetic coder is a port of the one in Crinkler, done by Mentor and Blueberry.
- Wrapping my head around all of this was aided by the videos of Jeff Miller and the compression seminar by Ferris at Revision 2020.
- Some of my porting efforts were eased by the work done by aufdj.