async_compression/
zstd.rs

1//! This module contains zstd-specific types for async-compression.
2
3/// A compression parameter for zstd. This is a stable wrapper around zstd's own `CParameter`
4/// type, to abstract over different versions of the zstd library.
5///
6/// See the [zstd documentation](https://facebook.github.io/zstd/zstd_manual.html) for more
7/// information on these parameters.
8#[derive(Copy, Clone, Debug, PartialEq, Eq)]
9pub struct CParameter(libzstd::stream::raw::CParameter);
10
11impl CParameter {
12    /// Window size in bytes (as a power of two)
13    pub fn window_log(value: u32) -> Self {
14        Self(libzstd::stream::raw::CParameter::WindowLog(value))
15    }
16
17    /// Size of the initial probe table in 4-byte entries (as a power of two)
18    pub fn hash_log(value: u32) -> Self {
19        Self(libzstd::stream::raw::CParameter::HashLog(value))
20    }
21
22    /// Size of the multi-probe table in 4-byte entries (as a power of two)
23    pub fn chain_log(value: u32) -> Self {
24        Self(libzstd::stream::raw::CParameter::ChainLog(value))
25    }
26
27    /// Number of search attempts (as a power of two)
28    pub fn search_log(value: u32) -> Self {
29        Self(libzstd::stream::raw::CParameter::SearchLog(value))
30    }
31
32    /// Minimum size of matches searched for
33    pub fn min_match(value: u32) -> Self {
34        Self(libzstd::stream::raw::CParameter::MinMatch(value))
35    }
36
37    /// Strategy-dependent length modifier
38    pub fn target_length(value: u32) -> Self {
39        Self(libzstd::stream::raw::CParameter::TargetLength(value))
40    }
41
42    /// Enable long-distance matching mode to look for and emit long-distance references.
43    ///
44    /// This increases the default window size.
45    pub fn enable_long_distance_matching(value: bool) -> Self {
46        Self(libzstd::stream::raw::CParameter::EnableLongDistanceMatching(value))
47    }
48
49    /// Size of the long-distance matching table (as a power of two)
50    pub fn ldm_hash_log(value: u32) -> Self {
51        Self(libzstd::stream::raw::CParameter::LdmHashLog(value))
52    }
53
54    /// Minimum size of long-distance matches searched for
55    pub fn ldm_min_match(value: u32) -> Self {
56        Self(libzstd::stream::raw::CParameter::LdmMinMatch(value))
57    }
58
59    /// Size of each bucket in the LDM hash table for collision resolution (as a power of two)
60    pub fn ldm_bucket_size_log(value: u32) -> Self {
61        Self(libzstd::stream::raw::CParameter::LdmBucketSizeLog(value))
62    }
63
64    /// Frequency of using the LDM hash table (as a power of two)
65    pub fn ldm_hash_rate_log(value: u32) -> Self {
66        Self(libzstd::stream::raw::CParameter::LdmHashRateLog(value))
67    }
68
69    /// Emit the size of the content (default: true).
70    pub fn content_size_flag(value: bool) -> Self {
71        Self(libzstd::stream::raw::CParameter::ContentSizeFlag(value))
72    }
73
74    /// Emit a checksum (default: false).
75    pub fn checksum_flag(value: bool) -> Self {
76        Self(libzstd::stream::raw::CParameter::ChecksumFlag(value))
77    }
78
79    /// Emit a dictionary ID when using a custom dictionary (default: true).
80    pub fn dict_id_flag(value: bool) -> Self {
81        Self(libzstd::stream::raw::CParameter::DictIdFlag(value))
82    }
83
84    /// Number of threads to spawn.
85    ///
86    /// If set to 0, compression functions will block; if set to 1 or more, compression will
87    /// run in background threads and `flush` pushes bytes through the compressor.
88    ///
89    /// # Panics
90    ///
91    /// This parameter requires feature `zstdmt` to be enabled, otherwise it will cause a panic
92    /// when used in `ZstdEncoder::with_quality_and_params()` calls.
93    //
94    // TODO: make this a normal feature guarded fn on next breaking release
95    #[cfg_attr(docsrs, doc(cfg(feature = "zstdmt")))]
96    pub fn nb_workers(value: u32) -> Self {
97        Self(libzstd::stream::raw::CParameter::NbWorkers(value))
98    }
99
100    /// Number of bytes given to each worker.
101    ///
102    /// If set to 0, zstd selects a job size based on compression parameters.
103    pub fn job_size(value: u32) -> Self {
104        Self(libzstd::stream::raw::CParameter::JobSize(value))
105    }
106
107    pub(crate) fn as_zstd(&self) -> libzstd::stream::raw::CParameter {
108        self.0
109    }
110}
111
112/// A decompression parameter for zstd. This is a stable wrapper around zstd's own `DParameter`
113/// type, to abstract over different versions of the zstd library.
114///
115/// See the [zstd documentation](https://facebook.github.io/zstd/zstd_manual.html) for more
116/// information on these parameters.
117#[derive(Copy, Clone, Debug, PartialEq, Eq)]
118pub struct DParameter(libzstd::stream::raw::DParameter);
119
120impl DParameter {
121    /// Maximum window size in bytes (as a power of two)
122    pub fn window_log_max(value: u32) -> Self {
123        Self(libzstd::stream::raw::DParameter::WindowLogMax(value))
124    }
125
126    pub(crate) fn as_zstd(&self) -> libzstd::stream::raw::DParameter {
127        self.0
128    }
129}
async_compression/zstd.rs

async_compression/
zstd.rs
