1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204
//! A DEFLATE-based stream compression/decompression library
//!
//! This library provides support for compression and decompression of
//! DEFLATE-based streams:
//!
//! * the DEFLATE format itself
//! * the zlib format
//! * gzip
//!
//! These three formats are all closely related and largely only differ in their
//! headers/footers. This crate has three types in each submodule for dealing
//! with these three formats.
//!
//! # Implementation
//!
//! In addition to supporting three formats, this crate supports several different
//! backends, controlled through this crate's features:
//!
//! * `default`, or `rust_backend` - this implementation uses the `miniz_oxide`
//! crate which is a port of `miniz.c` (below) to Rust. This feature does not
//! require a C compiler and only requires Rust code.
//!
//! * `zlib` - this feature will enable linking against the `libz` library, typically found on most
//! Linux systems by default. If the library isn't found to already be on the system it will be
//! compiled from source (this is a C library).
//!
//! There's various tradeoffs associated with each implementation, but in general you probably
//! won't have to tweak the defaults. The default choice is selected to avoid the need for a C
//! compiler at build time. `zlib-ng-compat` is useful if you're using zlib for compatibility but
//! want performance via zlib-ng's zlib-compat mode. `zlib` is useful if something else in your
//! dependencies links the original zlib so you cannot use zlib-ng-compat. The compression ratios
//! and performance of each of these feature should be roughly comparable, but you'll likely want
//! to run your own tests if you're curious about the performance.
//!
//! # Organization
//!
//! This crate consists mainly of three modules, [`read`], [`write`], and
//! [`bufread`]. Each module contains a number of types used to encode and
//! decode various streams of data.
//!
//! All types in the [`write`] module work on instances of [`Write`][write],
//! whereas all types in the [`read`] module work on instances of
//! [`Read`][read] and [`bufread`] works with [`BufRead`][bufread]. If you
//! are decoding directly from a `&[u8]`, use the [`bufread`] types.
//!
//! ```
//! use flate2::write::GzEncoder;
//! use flate2::Compression;
//! use std::io;
//! use std::io::prelude::*;
//!
//! # fn main() { let _ = run(); }
//! # fn run() -> io::Result<()> {
//! let mut encoder = GzEncoder::new(Vec::new(), Compression::default());
//! encoder.write_all(b"Example")?;
//! # Ok(())
//! # }
//! ```
//!
//!
//! Other various types are provided at the top-level of the crate for
//! management and dealing with encoders/decoders. Also note that types which
//! operate over a specific trait often implement the mirroring trait as well.
//! For example a `flate2::read::DeflateDecoder<T>` *also* implements the
//! `Write` trait if `T: Write`. That is, the "dual trait" is forwarded directly
//! to the underlying object if available.
//!
//! [`read`]: read/index.html
//! [`bufread`]: bufread/index.html
//! [`write`]: write/index.html
//! [read]: https://doc.rust-lang.org/std/io/trait.Read.html
//! [write]: https://doc.rust-lang.org/std/io/trait.Write.html
//! [bufread]: https://doc.rust-lang.org/std/io/trait.BufRead.html
#![doc(html_root_url = "https://docs.rs/flate2/0.2")]
#![deny(missing_docs)]
#![deny(missing_debug_implementations)]
#![allow(trivial_numeric_casts)]
#![cfg_attr(test, deny(warnings))]
pub use crate::crc::{Crc, CrcReader, CrcWriter};
pub use crate::gz::GzBuilder;
pub use crate::gz::GzHeader;
pub use crate::mem::{Compress, CompressError, Decompress, DecompressError, Status};
pub use crate::mem::{FlushCompress, FlushDecompress};
mod bufreader;
mod crc;
mod deflate;
mod ffi;
mod gz;
mod mem;
mod zio;
mod zlib;
/// Types which operate over [`Read`] streams, both encoders and decoders for
/// various formats.
///
/// [`Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
pub mod read {
pub use crate::deflate::read::DeflateDecoder;
pub use crate::deflate::read::DeflateEncoder;
pub use crate::gz::read::GzDecoder;
pub use crate::gz::read::GzEncoder;
pub use crate::gz::read::MultiGzDecoder;
pub use crate::zlib::read::ZlibDecoder;
pub use crate::zlib::read::ZlibEncoder;
}
/// Types which operate over [`Write`] streams, both encoders and decoders for
/// various formats.
///
/// [`Write`]: https://doc.rust-lang.org/std/io/trait.Write.html
pub mod write {
pub use crate::deflate::write::DeflateDecoder;
pub use crate::deflate::write::DeflateEncoder;
pub use crate::gz::write::GzDecoder;
pub use crate::gz::write::GzEncoder;
pub use crate::zlib::write::ZlibDecoder;
pub use crate::zlib::write::ZlibEncoder;
}
/// Types which operate over [`BufRead`] streams, both encoders and decoders for
/// various formats.
///
/// [`BufRead`]: https://doc.rust-lang.org/std/io/trait.BufRead.html
pub mod bufread {
pub use crate::deflate::bufread::DeflateDecoder;
pub use crate::deflate::bufread::DeflateEncoder;
pub use crate::gz::bufread::GzDecoder;
pub use crate::gz::bufread::GzEncoder;
pub use crate::gz::bufread::MultiGzDecoder;
pub use crate::zlib::bufread::ZlibDecoder;
pub use crate::zlib::bufread::ZlibEncoder;
}
fn _assert_send_sync() {
fn _assert_send_sync<T: Send + Sync>() {}
_assert_send_sync::<read::DeflateEncoder<&[u8]>>();
_assert_send_sync::<read::DeflateDecoder<&[u8]>>();
_assert_send_sync::<read::ZlibEncoder<&[u8]>>();
_assert_send_sync::<read::ZlibDecoder<&[u8]>>();
_assert_send_sync::<read::GzEncoder<&[u8]>>();
_assert_send_sync::<read::GzDecoder<&[u8]>>();
_assert_send_sync::<read::MultiGzDecoder<&[u8]>>();
_assert_send_sync::<write::DeflateEncoder<Vec<u8>>>();
_assert_send_sync::<write::DeflateDecoder<Vec<u8>>>();
_assert_send_sync::<write::ZlibEncoder<Vec<u8>>>();
_assert_send_sync::<write::ZlibDecoder<Vec<u8>>>();
_assert_send_sync::<write::GzEncoder<Vec<u8>>>();
_assert_send_sync::<write::GzDecoder<Vec<u8>>>();
}
/// When compressing data, the compression level can be specified by a value in
/// this enum.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub struct Compression(u32);
impl Compression {
/// Creates a new description of the compression level with an explicitly
/// specified integer.
///
/// The integer here is typically on a scale of 0-9 where 0 means "no
/// compression" and 9 means "take as long as you'd like".
pub const fn new(level: u32) -> Compression {
Compression(level)
}
/// No compression is to be performed, this may actually inflate data
/// slightly when encoding.
pub const fn none() -> Compression {
Compression(0)
}
/// Optimize for the best speed of encoding.
pub const fn fast() -> Compression {
Compression(1)
}
/// Optimize for the size of data being encoded.
pub const fn best() -> Compression {
Compression(9)
}
/// Returns an integer representing the compression level, typically on a
/// scale of 0-9
pub fn level(&self) -> u32 {
self.0
}
}
impl Default for Compression {
fn default() -> Compression {
Compression(6)
}
}
#[cfg(test)]
fn random_bytes() -> impl Iterator<Item = u8> {
use rand::Rng;
use std::iter;
iter::repeat(()).map(|_| rand::thread_rng().gen())
}