flate2

A streaming compression/decompression library DEFLATE-based streams in Rust.

This crate by default uses the miniz_oxide crate, a port of miniz.c to pure Rust. This crate also supports other backends, such as the widely available zlib library or the high-performance zlib-ng library.

Supported formats:

• deflate
• zlib
• gzip

# Cargo.toml
[dependencies]
flate2 = "1.0"

Compression

use std::io::prelude::*;
use flate2::Compression;
use flate2::write::ZlibEncoder;

fn main() {
    let mut e = ZlibEncoder::new(Vec::new(), Compression::default());
    e.write_all(b"foo");
    e.write_all(b"bar");
    let compressed_bytes = e.finish();
}

Decompression

use std::io::prelude::*;
use flate2::read::GzDecoder;

fn main() {
    let mut d = GzDecoder::new("...".as_bytes());
    let mut s = String::new();
    d.read_to_string(&mut s).unwrap();
    println!("{}", s);
}

Backends

The default miniz_oxide backend has the advantage of being pure Rust, but if you're already using zlib with another C library, for example, you can use that for Rust code as well:

[dependencies]
flate2 = { version = "1.0.17", features = ["zlib"], default-features = false }

This supports either the high-performance zlib-ng backend (in zlib-compat mode) or the use of a shared system zlib library. To explicitly opt into the fast zlib-ng backend, use:

[dependencies]
flate2 = { version = "1.0.17", features = ["zlib-ng-compat"], default-features = false }

Note that if any crate in your dependency graph explicitly requests stock zlib, or uses libz-sys directly without default-features = false, you'll get stock zlib rather than zlib-ng. See the libz-sys README for details.

For compatibility with previous versions of flate2, the cloudflare optimized version of zlib is available, via the cloudflare_zlib feature. It's not as fast as zlib-ng, but it's faster than stock zlib. It requires a x86-64 CPU with SSE 4.2 or ARM64 with NEON & CRC. It does not support 32-bit CPUs at all and is incompatible with mingw. For more information check the crate documentation. Note that cloudflare_zlib will cause breakage if any other crate in your crate graph uses another version of zlib/libz.

For compatibility with previous versions of flate2, the C version of miniz.c is still available, using the feature miniz-sys.

License

This project is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.