#lzss #compression #no-std

no-std lzss

A LZSS en-/decompressor (lossless data compression, no_std capable, in pure Rust)

3 releases

0.8.2 Sep 26, 2021
0.8.1 Jul 15, 2021
0.8.0 Jun 7, 2021

#45 in Compression

25 downloads per month
Used in lzss-cli

MIT license

51KB
1K SLoC

Lempel–Ziv–Storer–Szymanski de-/compression

lzss is a lossless data compression algorithm in pure Rust. This crate is built for embedded systems:

  • Small code size
  • Uses little RAM and CPU
  • no_std feature
  • All parameters can be compile-time only

Generic vs. dynamic

This crate comes in two flavors: generic (Lzss) and dynamic (LzssDyn).

The dynamic one has one compress function and all parameters are passed to it at runtime, making it very adaptive.

The generic one has compile-time parameters will produce a function for each different sets of parameters. This function will be more optimized by the compiler than the dynamic one, the downside is that multiple functions are generated when multiple parameter sets are used.

(The same applies for decompress and other functions, only used function will be in the generated program.)

Lack of a header

This algorithm has by design no header at all. Please be aware that it is not possible to check if the contents is correct, or even the length matches. It is recommended to add a header based on the requirements.

Origin

This code is based on the LZSS encoder-decoder by Haruhiko Okumura, public domain.

Features

  • alloc - Enables everything marked with alloc.
  • std - Enables everything marked with std and the Error instance for LzssError and LzssDynError.
  • const_panic - Requires nightly and enables compile-time checks of the parameters for Lzss.

Example

use lzss::{Lzss, SliceReader, SliceWriter};

type MyLzss = Lzss<10, 4, 0x20, {1 << 10}, {2 << 10}>;
let input = b"Example Data";
let mut output = [0; 30];
let result = MyLzss::compress(
  SliceReader::new(input),
  SliceWriter::new(&mut output),
);
assert_eq!(result, Ok(14)); // there was no overflow and the output is 14 bytes long

Command-Line-Interface

In oder to de-/compress files in the cli, install lzss-cli:

cargo install lzss-cli

Example:

lzss e 10,4,0x20 <input >outout

Dependencies