mopenzl 0.1.0

OpenZL compression and decompression in safe Rust; encoding is byte-identical to Meta's reference library
Documentation 
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
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260

//! Safe Rust [OpenZL] codecs, independently selected with Cargo features.
//!
//! OpenZL is Meta's format-aware compression framework: a frame records the
//! graph of codecs that produced it, so one universal decoder reads every
//! frame. This crate ports the framework's core to Rust, starting with what
//! `ZL_compress` and `ZL_decompress` do for serial data:
//!
//! - **Byte-identical encoder.** For the same input and global parameters
//!   (level, format version, checksums), [`Compressor`] writes exactly the
//!   frame of OpenZL v0.3.0's `ZL_CCtx_compress` with its default graph, or,
//!   with [`Chunking::Fixed`], of its serial segmenter. Inputs below ten bytes
//!   are stored, larger ones go through Zstandard (the safe-Rust `mzstd`,
//!   byte-identical to the zstd 1.5.7 OpenZL vendors), and any chunk that
//!   would grow is stored instead.
//! - **Decoder** for frames of format versions 21 to 27 built from those
//!   codecs, with both checksums verified, bounded input and output, and
//!   precise errors for frames that need codecs not ported yet.
//! - **No `unsafe`.** Kernels use [`fearless_simd`] with the instruction set
//!   detected once per codec ([`Backend`]); every backend writes the same
//!   bytes.
//! - **Sans-I/O sessions** that work only with the buffers you pass in, plus
//!   `std::io` adapters.
//!
//! `compression` and `decompression` are enabled by default. Disable default
//! features and select either codec alongside `std` or `no_std`:
//!
//! ```toml
//! mopenzl = { version = "0.1", default-features = false, features = ["std", "decompression"] }
//! ```
//!
//! # Choose your API
//!
//! | I/O shape | Compression | Decompression |
//! | --- | --- | --- |
//! | Return a new `Vec<u8>` | [`Compressor::compress`] | [`Decompressor::decompress`] |
//! | Append to an existing Vec | [`Compressor::compress_into`] | [`Decompressor::decompress_into`] |
//! | Write into a caller-owned slice | [`Compressor::compress_to_slice`] | [`Decompressor::decompress_to_slice`] |
//! | Write into uninitialized memory | [`Compressor::compress_to_uninit`] | [`Decompressor::decompress_to_uninit`] |
//! | Pull output through `std::io::Read` | `Compressor::reader` | `Decompressor::reader` |
//! | Push input through `std::io::Write` | `Compressor::writer` | `Decompressor::writer` |
//! | Drive input/output incrementally | [`Compressor::start`] → [`EncoderSession`] | [`Decompressor::start`] → [`DecoderSession`] |
//! | Same, into uninitialized memory | [`EncoderSession::process_uninit`] | [`DecoderSession::process_uninit`] |
//! | Same, with the session owning the codec | [`Compressor::into_session`] → [`EncoderSessionOwned`] | [`Decompressor::into_session`] → [`DecoderSessionOwned`] |
//!
//! ```rust
//! use mopenzl::{Compressor, Decompressor, EncoderConfig, Level};
//!
//! let mut encoder = Compressor::new(EncoderConfig::from(Level::try_from(3)?))?;
//! let mut decoder = Decompressor::default();
//! let mut frame = Vec::new();
//! for input in [b"first payload".as_slice(), b"second payload".as_slice()] {
//!     frame.clear(); // Keep the allocation; compress_into appends.
//!     encoder.compress_into(input, &mut frame)?;
//!     assert_eq!(decoder.decompress(&frame)?, input);
//! }
//! # Ok::<(), Box<dyn std::error::Error>>(())
//! ```
//!
//! # Streaming and chunks
//!
//! A frame header records the frame's total size, and the reference decoder
//! rejects frames that leave it unknown. Declare the size with
//! [`InputSize::Exact`] when you know it: a session then writes the header at
//! once and holds at most one chunk of input. With [`InputSize::Unknown`] it
//! holds the whole input until the frame ends. [`Chunking::Fixed`] bounds a
//! chunk, so with a declared size both the encoder and the decoder work in
//! bounded memory; the default, [`Chunking::Whole`], matches `ZL_compress`.
//!
//! ```rust
//! # #[cfg(not(feature = "no_std"))]
//! # {
//! use mopenzl::{ChunkSize, Chunking, Compressor, Decompressor, EncoderConfig, InputSize};
//! use std::io::{Read, Write};
//!
//! let payload = b"streamed payload ".repeat(10_000);
//! let config = EncoderConfig::default().with_chunking(Chunking::Fixed(ChunkSize::MIN));
//! let mut encoder = Compressor::new(config)?;
//! let mut writer = encoder.writer(Vec::new(), InputSize::Exact(payload.len() as u64).into());
//! writer.write_all(&payload)?;
//! let frame = writer.finish().map_err(mopenzl::io::FinishError::into_error)?;
//!
//! let mut decoder = Decompressor::default();
//! let mut content = Vec::new();
//! decoder.reader(&frame[..]).read_to_end(&mut content)?;
//! assert_eq!(content, payload);
//! # }
//! # Ok::<(), Box<dyn std::error::Error>>(())
//! ```
//!
//! # Untrusted input
//!
//! Limits are unlimited by default; set [`DecodeLimits`] for untrusted
//! frames. A frame declaring more output than allowed fails before any chunk
//! is decoded.
//!
//! ```rust
//! use mopenzl::{DecodeLimits, DecoderConfig, Decompressor};
//!
//! let limits = DecodeLimits::default()
//!     .with_max_input_bytes(Some(1 << 20))
//!     .with_max_output_bytes(Some(8 << 20));
//! let mut decoder = Decompressor::new(limits.into());
//! assert!(decoder.decompress(b"not a frame").is_err());
//! ```
//!
//! # Select codecs
//!
//! Features are additive; the defaults enable everything.
//!
//! | Feature | Enables |
//! | --- | --- |
//! | `compression` | [`Compressor`] and its sessions |
//! | `decompression` | [`Decompressor`] and its sessions |
//! | `std` | the `std::io` adapters, `std::error::Error` and runtime SIMD detection |
//! | `no_std` | alloc-only builds with the compile-time SIMD baseline |
//! | `zstd` | the Zstandard codec (`mzstd`), the default graph's backend |
//!
//! Every OpenZL codec has its own feature, all enabled by default. Without a
//! codec's feature the encoder never writes it (chunks that would use it are
//! stored, so frames stop matching the reference's default graph) and the
//! decoder reports frames using it as [`Unsupported`].
//!
//! ```toml
//! mopenzl = { version = "0.1", default-features = false, features = ["std", "decompression", "zstd"] }
//! ```
//!
//! [OpenZL]: https://github.com/facebook/openzl
#![cfg_attr(
    feature = "compression",
    doc = r#"
[`Chunking::Fixed`]: crate::Chunking::Fixed
[`Chunking::Whole`]: crate::Chunking::Whole
[`Compressor::compress_into`]: crate::Compressor::compress_into
[`Compressor::compress_to_slice`]: crate::Compressor::compress_to_slice
[`Compressor::compress_to_uninit`]: crate::Compressor::compress_to_uninit
[`Compressor::compress`]: crate::Compressor::compress
[`Compressor::into_session`]: crate::Compressor::into_session
[`Compressor::start`]: crate::Compressor::start
[`Compressor`]: crate::Compressor
[`EncoderSession::process_uninit`]: crate::EncoderSession::process_uninit
[`EncoderSessionOwned`]: crate::EncoderSessionOwned
[`EncoderSession`]: crate::EncoderSession
[`InputSize::Exact`]: crate::InputSize::Exact
[`InputSize::Unknown`]: crate::InputSize::Unknown
"#
)]
#![cfg_attr(
    not(feature = "compression"),
    doc = r#"
[`Chunking::Fixed`]: #select-codecs
[`Chunking::Whole`]: #select-codecs
[`Compressor::compress_into`]: #select-codecs
[`Compressor::compress_to_slice`]: #select-codecs
[`Compressor::compress_to_uninit`]: #select-codecs
[`Compressor::compress`]: #select-codecs
[`Compressor::into_session`]: #select-codecs
[`Compressor::start`]: #select-codecs
[`Compressor`]: #select-codecs
[`EncoderSession::process_uninit`]: #select-codecs
[`EncoderSessionOwned`]: #select-codecs
[`EncoderSession`]: #select-codecs
[`InputSize::Exact`]: #select-codecs
[`InputSize::Unknown`]: #select-codecs
"#
)]
#![cfg_attr(
    feature = "decompression",
    doc = r#"
[`DecodeLimits`]: crate::DecodeLimits
[`DecoderSession::process_uninit`]: crate::DecoderSession::process_uninit
[`DecoderSessionOwned`]: crate::DecoderSessionOwned
[`DecoderSession`]: crate::DecoderSession
[`Decompressor::decompress_into`]: crate::Decompressor::decompress_into
[`Decompressor::decompress_to_slice`]: crate::Decompressor::decompress_to_slice
[`Decompressor::decompress_to_uninit`]: crate::Decompressor::decompress_to_uninit
[`Decompressor::decompress`]: crate::Decompressor::decompress
[`Decompressor::into_session`]: crate::Decompressor::into_session
[`Decompressor::start`]: crate::Decompressor::start
[`Decompressor`]: crate::Decompressor
"#
)]
#![cfg_attr(
    not(feature = "decompression"),
    doc = r#"
[`DecodeLimits`]: #select-codecs
[`DecoderSession::process_uninit`]: #select-codecs
[`DecoderSessionOwned`]: #select-codecs
[`DecoderSession`]: #select-codecs
[`Decompressor::decompress_into`]: #select-codecs
[`Decompressor::decompress_to_slice`]: #select-codecs
[`Decompressor::decompress_to_uninit`]: #select-codecs
[`Decompressor::decompress`]: #select-codecs
[`Decompressor::into_session`]: #select-codecs
[`Decompressor::start`]: #select-codecs
[`Decompressor`]: #select-codecs
"#
)]
#![cfg_attr(
    not(feature = "decompression"),
    doc = "[`Unsupported`]: #select-codecs"
)]
#![cfg_attr(
    not(any(feature = "compression", feature = "decompression")),
    doc = "[`Backend`]: #select-codecs\n\n[`fearless_simd`]: https://docs.rs/fearless_simd"
)]
#![cfg_attr(not(test), forbid(unsafe_code))]
#![cfg_attr(feature = "no_std", no_std)]
#![deny(missing_docs)]
#![deny(missing_debug_implementations)]
#![deny(rustdoc::broken_intra_doc_links)]

#[cfg(any(feature = "compression", feature = "decompression"))]
extern crate alloc;

#[cfg(test)]
extern crate std;

#[cfg(any(feature = "compression", feature = "decompression"))]
mod backend;
#[cfg(any(feature = "compression", feature = "decompression"))]
mod format;
#[cfg(any(feature = "compression", feature = "decompression"))]
mod retention;
#[cfg(any(feature = "compression", feature = "decompression"))]
mod shared;
#[cfg(any(feature = "compression", feature = "decompression"))]
pub use backend::Backend;
#[cfg(any(feature = "compression", feature = "decompression"))]
pub use format::{FormatVersion, UnsupportedFormatVersion};
#[cfg(any(feature = "compression", feature = "decompression"))]
pub use retention::RetentionPolicy;

#[cfg(all(
    any(feature = "compression", feature = "decompression"),
    not(feature = "no_std")
))]
mod finish_error;
#[cfg(all(
    any(feature = "compression", feature = "decompression"),
    not(feature = "no_std")
))]
pub mod io;

#[cfg(feature = "compression")]
pub mod compressor;
#[cfg(feature = "compression")]
pub use compressor::{
    ChunkSize, Chunking, Compressor, CompressorBuilder, ConfigError, EncodeError, EncoderConfig,
    EncoderSession, EncoderSessionOwned, EncoderStatus, InputSize, Level, Operation, Parameter,
    Progress, SizeOverflow, StreamConfig,
};

#[cfg(feature = "decompression")]
pub mod decompressor;
#[cfg(feature = "decompression")]
pub use decompressor::{
    DecodeError, DecodeFailure, DecodeLimits, DecodeOperation, DecodeProgress, DecoderConfig,
    DecoderSession, DecoderSessionOwned, DecoderStatus, Decompressor, DecompressorBuilder,
    FrameMode, InvalidDataKind, Unsupported,
};