Re-implement in pure Rust

[newpavlov]

Are you interested in re-implementing bzip2 in pure Rust or do you intend to keep it as a binding? (i.e. will you accept such work if anyone will be interested in it or not?) bzip2-sys implementation could be kept as a feature-gated disabled by default option.

Potential rewrite will help with the licensing issue and will help crates which target WASM.

[alexcrichton]

Sounds like a good idea to me! I think a strategy similar to flate2 where the implementation is in a separate crate probably works best, and then this crate can multiplex backends as necessary.

[infinity0]

The new bzip2 (C library) maintainer has actually started rewriting it in rust.

[dralley]

Granted, it does not look like they are being very active with development. No commits in more than 7 months.

[paolobarbolini]

Hello, I just published a pure Rust bzip2 decompressor implementation. I'll also probably work on the encoder in the future. In the meantime I already published a 0.1.0 on crates.io, which you can find here: https://crates.io/crates/bzip2-rs

[val-ms]

@ohsnyt has a pure Rust bzip2 multi-threaded compressor and decompressor in progress, here: https://github.com/ohsnyt/bzip2-rust It is functional, but is not yet published on crates.io.

If anyone is interested in helping test, and fine tune it, I'm sure he would appreciate the help.

[folkertdev]

The latest 0.5.0 release https://crates.io/crates/bzip2/0.5.0 can use libbzip2-rs with a feature flag. libbzip2-rs was translated using c2rust from the original bzip2 C source, and subsequently made safe to the extent possible (we want to remain fully API-compatible). It gives byte-for-byte the same output as stock bzip2, though currently it performs a couple percent worse than it.

Concretely that means that no C toolchain is needed when this crate is compiled using:

bzip2 = { version = "0.5.0", default-features = false, features = ["libbz2-rs-sys"] }

This should make cross-compilation much easier (e.g. for webassembly), and generally is a fix for a bunch of linker related open issues.