1# flate2 2 3[](https://crates.io/crates/flate2) 4[](https://docs.rs/flate2) 5 6A streaming compression/decompression library DEFLATE-based streams in Rust. 7 8This crate by default uses the `miniz_oxide` crate, a port of `miniz.c` to pure 9Rust. This crate also supports other [backends](#Backends), such as the widely 10available zlib library or the high-performance zlib-ng library. 11 12Supported formats: 13 14* deflate 15* zlib 16* gzip 17 18```toml 19# Cargo.toml 20[dependencies] 21flate2 = "1.0" 22``` 23 24## Compression 25 26```rust 27use std::io::prelude::*; 28use flate2::Compression; 29use flate2::write::ZlibEncoder; 30 31fn main() { 32 let mut e = ZlibEncoder::new(Vec::new(), Compression::default()); 33 e.write_all(b"foo"); 34 e.write_all(b"bar"); 35 let compressed_bytes = e.finish(); 36} 37``` 38 39## Decompression 40 41```rust,no_run 42use std::io::prelude::*; 43use flate2::read::GzDecoder; 44 45fn main() { 46 let mut d = GzDecoder::new("...".as_bytes()); 47 let mut s = String::new(); 48 d.read_to_string(&mut s).unwrap(); 49 println!("{}", s); 50} 51``` 52 53## Backends 54 55The default `miniz_oxide` backend has the advantage of being pure Rust. If you 56want maximum performance, you can use the zlib-ng C library: 57 58```toml 59[dependencies] 60flate2 = { version = "1.0.17", features = ["zlib-ng"], default-features = false } 61``` 62 63Note that the `"zlib-ng"` feature works even if some other part of your crate 64graph depends on zlib. 65 66However, if you're already using another C or Rust library that depends on 67zlib, and you want to avoid including both zlib and zlib-ng, you can use that 68for Rust code as well: 69 70```toml 71[dependencies] 72flate2 = { version = "1.0.17", features = ["zlib"], default-features = false } 73``` 74 75Or, if you have C or Rust code that depends on zlib and you want to use zlib-ng 76via libz-sys in zlib-compat mode, use: 77 78```toml 79[dependencies] 80flate2 = { version = "1.0.17", features = ["zlib-ng-compat"], default-features = false } 81``` 82 83Note that when using the `"zlib-ng-compat"` feature, if any crate in your 84dependency graph explicitly requests stock zlib, or uses libz-sys directly 85without `default-features = false`, you'll get stock zlib rather than zlib-ng. 86See [the libz-sys 87README](https://github.com/rust-lang/libz-sys/blob/main/README.md) for details. 88To avoid that, use the `"zlib-ng"` feature instead. 89 90For compatibility with previous versions of `flate2`, the Cloudflare optimized 91version of zlib is available, via the `cloudflare_zlib` feature. It's not as 92fast as zlib-ng, but it's faster than stock zlib. It requires an x86-64 CPU with 93SSE 4.2 or ARM64 with NEON & CRC. It does not support 32-bit CPUs at all and is 94incompatible with mingw. For more information check the [crate 95documentation](https://crates.io/crates/cloudflare-zlib-sys). Note that 96`cloudflare_zlib` will cause breakage if any other crate in your crate graph 97uses another version of zlib/libz. 98 99# License 100 101This project is licensed under either of 102 103 * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or 104 https://www.apache.org/licenses/LICENSE-2.0) 105 * MIT license ([LICENSE-MIT](LICENSE-MIT) or 106 https://opensource.org/licenses/MIT) 107 108at your option. 109 110### Contribution 111 112Unless you explicitly state otherwise, any contribution intentionally submitted 113for inclusion in this project by you, as defined in the Apache-2.0 license, 114shall be dual licensed as above, without any additional terms or conditions. 115
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