zenzop

A faster fork of the Zopfli DEFLATE compressor, written in Rust.

Zopfli produces the smallest possible DEFLATE output at the cost of speed. zenzop produces byte-identical output 2-3x faster through algorithmic improvements: precomputed lookup tables, arena-free Huffman tree construction, pre-allocated stores, and eliminated bounds checks in hot paths.

Features

• Byte-identical output to the C Zopfli reference implementation
• 2-3x faster than the original Rust port
• no_std + alloc compatible — works on embedded and WASM targets
• Cooperative cancellation via enough::Stop — cancel long-running compressions cleanly
• Streaming encoder API — DeflateEncoder, GzipEncoder, ZlibEncoder
• Parallel block compression with optional rayon support

Usage

Add to your Cargo.toml:

[dependencies]
zenzop = "0.1"

Compress data

use std::io;

fn main() -> io::Result<()> {
    let data = b"Hello, world!";
    let mut output = Vec::new();

    zenzop::compress(
        zenzop::Options::default(),
        zenzop::Format::Gzip,
        &data[..],
        &mut output,
    )?;

    Ok(())
}

Streaming encoder

use std::io::{self, Write};

fn main() -> io::Result<()> {
    let mut encoder = zenzop::DeflateEncoder::new_buffered(
        zenzop::Options::default(),
        zenzop::BlockType::Dynamic,
        Vec::new(),
    );
    encoder.write_all(b"Hello, world!")?;
    let compressed = encoder.into_inner()?.finish()?;
    Ok(())
}

With cancellation

use zenzop::{Options, Format, compress_with_stop, Unstoppable};

// Zero-cost when not needed:
let result = compress_with_stop(Options::default(), Format::Gzip, &data[..], &mut out, Unstoppable);

// With a real stop token (from the `almost-enough` crate):
// let result = compress_with_stop(Options::default(), Format::Gzip, &data[..], &mut out, stop);

Cargo features

For no_std usage: default-features = false.

MSRV

The minimum supported Rust version is 1.82. Bumping this is not considered a breaking change.

Building from source

cargo build --release

The zenzop binary will be at target/release/zenzop.

Testing

cargo test                    # Unit tests + property-based tests
./test/run.sh                 # Golden master: byte-identical to C Zopfli

License

Apache-2.0

Origin

Forked from zopfli-rs/zopfli, which was Carol Nichols' Rust reimplementation of Google's Zopfli.

AI-Generated Code Notice

Developed with Claude (Anthropic). Not all code manually reviewed. Review critical paths before production use.