zstd/
lib.rs

1//! Rust binding to the [zstd library][zstd].
2//!
3//! This crate provides:
4//!
5//! * An [encoder](stream/write/struct.Encoder.html) to compress data using zstd
6//!   and send the output to another write.
7//! * A [decoder](stream/read/struct.Decoder.html) to read input data from a `Read`
8//!   and decompress it.
9//! * Convenient functions for common tasks.
10//!
11//! # Example
12//!
13//! ```no_run
14//! use std::io;
15//!
16//! // Uncompress input and print the result.
17//! zstd::stream::copy_decode(io::stdin(), io::stdout()).unwrap();
18//! ```
19//!
20//! # Cargo features
21//!
22//! Enabled by default: `legacy`, `arrays`, `zdict_builder`.
23//!
24//! | Feature | Default | Description |
25//! | --- | --- | --- |
26//! | `arrays` | yes | Use fixed-size arrays (`[u8; N]`) as output buffers. |
27//! | `legacy` | yes | Decode frames written by zstd versions older than 0.8. |
28//! | `zdict_builder` | yes | Train new dictionaries. *Using* a dictionary always works. |
29//! | `experimental` | | Expose zstd's experimental API, which has no stability guarantees. |
30//! | `zstdmt` | | Multi-threaded compression inside the C library. |
31//! | `thin` | | Build a smaller C library, at some cost in speed and error reporting. |
32//! | `debug` | | Enable zstd's debug logs. |
33//! | `no_asm` | | Do not build the x86-64 assembly. |
34//! | `fat-lto`, `thin-lto` | | Cross-language LTO. Only works if `clang` builds the C library. |
35//! | `bindgen` | | Generate the bindings at build time rather than using the pre-generated ones. |
36//! | `pkg-config` | | Link against a system-installed libzstd instead of building the bundled source. |
37//! | `vendored` | | Always build the bundled source, even when `pkg-config` is also enabled. |
38//! | `cmake` | | Build the C library with zstd's own CMake files instead of the `cc` crate. |
39//!
40//! See the [readme] for more about the build-related ones.
41//!
42//! [zstd]: https://github.com/facebook/zstd
43//! [readme]: https://github.com/gyscos/zstd-rs#cargo-features
44#![deny(missing_docs)]
45#![cfg_attr(feature = "doc-cfg", feature(doc_cfg))]
46
47// Re-export the zstd-safe crate.
48pub use zstd_safe;
49
50pub mod bulk;
51pub mod dict;
52
53#[macro_use]
54pub mod stream;
55
56use std::io;
57
58/// Default compression level.
59pub use zstd_safe::CLEVEL_DEFAULT as DEFAULT_COMPRESSION_LEVEL;
60
61/// The accepted range of compression levels.
62pub fn compression_level_range(
63) -> std::ops::RangeInclusive<zstd_safe::CompressionLevel> {
64    zstd_safe::min_c_level()..=zstd_safe::max_c_level()
65}
66
67/// How large a buffer a compressed block might need, at worst.
68///
69/// This is what to reserve before [`bulk::compress_to_buffer()`], which writes
70/// into a destination you provide rather than allocating one.
71///
72/// Re-exported from `zstd_safe`, where it lives alongside the rest of the
73/// direct bindings.
74pub use zstd_safe::compress_bound;
75
76#[doc(no_inline)]
77pub use crate::stream::{
78    compress_file, compress_file_into, compress_sized, compress_sized_into,
79    decode_all, decompressed_size, encode_all, Decoder, Encoder,
80};
81
82/// Returns the error message as io::Error based on error_code.
83fn map_error_code(code: usize) -> io::Error {
84    let msg = zstd_safe::get_error_name(code);
85    io::Error::new(io::ErrorKind::Other, msg.to_string())
86}
87
88// Some helper functions to write full-cycle tests.
89
90#[cfg(test)]
91fn test_cycle<F, G>(data: &[u8], f: F, g: G)
92where
93    F: Fn(&[u8]) -> Vec<u8>,
94    G: Fn(&[u8]) -> Vec<u8>,
95{
96    let mid = f(data);
97    let end = g(&mid);
98    assert_eq!(data, &end[..]);
99}
100
101#[cfg(test)]
102fn test_cycle_unwrap<F, G>(data: &[u8], f: F, g: G)
103where
104    F: Fn(&[u8]) -> io::Result<Vec<u8>>,
105    G: Fn(&[u8]) -> io::Result<Vec<u8>>,
106{
107    test_cycle(data, |data| f(data).unwrap(), |data| g(data).unwrap())
108}
109
110#[test]
111fn default_compression_level_in_range() {
112    assert!(compression_level_range().contains(&DEFAULT_COMPRESSION_LEVEL));
113}
zstd/lib.rs

zstd/
lib.rs
