|
Name |
|
Date |
Size |
#Lines |
LOC |
| .. | | - | - |
| .circleci/ | | 23-Nov-2023 | - | 89 | 51 |
| contrib/ | | 23-Nov-2023 | - | 1,506 | 1,138 |
| doc/ | | 23-Nov-2023 | - | 1,536 | 1,209 |
| examples/ | | 23-Nov-2023 | - | 2,847 | 1,967 |
| lib/ | | 23-Nov-2023 | - | 9,840 | 6,154 |
| ossfuzz/ | | 23-Nov-2023 | - | 1,120 | 771 |
| programs/ | | 23-Nov-2023 | - | 5,261 | 3,840 |
| tests/ | | 23-Nov-2023 | - | 6,340 | 4,866 |
| visual/ | | 23-Nov-2023 | - | 2,851 | 2,814 |
| .gitattributes | D | 23-Nov-2023 | 348 | 22 | 17 |
| .gitignore | D | 23-Nov-2023 | 315 | 39 | 31 |
| .travis.yml | D | 23-Nov-2023 | 6.1 KiB | 221 | 189 |
| INSTALL | D | 23-Nov-2023 | 630 | 17 | 13 |
| LICENSE | D | 23-Nov-2023 | 565 | 12 | 9 |
| METADATA | D | 23-Nov-2023 | 282 | 16 | 15 |
| MODULE_LICENSE_GPL | D | 23-Nov-2023 | 0 | | |
| Makefile | D | 23-Nov-2023 | 6.6 KiB | 204 | 129 |
| Makefile.inc | D | 23-Nov-2023 | 1.6 KiB | 88 | 77 |
| NEWS | D | 23-Nov-2023 | 13.4 KiB | 285 | 248 |
| OWNERS | D | 23-Nov-2023 | 46 | 2 | 1 |
| README.md | D | 23-Nov-2023 | 5.4 KiB | 122 | 92 |
| appveyor.yml | D | 23-Nov-2023 | 5.7 KiB | 142 | 135 |
README.md
1LZ4 - Extremely fast compression
2================================
3
4LZ4 is lossless compression algorithm,
5providing compression speed > 500 MB/s per core,
6scalable with multi-cores CPU.
7It features an extremely fast decoder,
8with speed in multiple GB/s per core,
9typically reaching RAM speed limits on multi-core systems.
10
11Speed can be tuned dynamically, selecting an "acceleration" factor
12which trades compression ratio for faster speed.
13On the other end, a high compression derivative, LZ4_HC, is also provided,
14trading CPU time for improved compression ratio.
15All versions feature the same decompression speed.
16
17LZ4 is also compatible with [dictionary compression](https://github.com/facebook/zstd#the-case-for-small-data-compression),
18both at [API](https://github.com/lz4/lz4/blob/v1.8.3/lib/lz4frame.h#L481) and [CLI](https://github.com/lz4/lz4/blob/v1.8.3/programs/lz4.1.md#operation-modifiers) levels.
19It can ingest any input file as dictionary, though only the final 64KB are used.
20This capability can be combined with the [Zstandard Dictionary Builder](https://github.com/facebook/zstd/blob/v1.3.5/programs/zstd.1.md#dictionary-builder),
21in order to drastically improve compression performance on small files.
22
23
24LZ4 library is provided as open-source software using BSD 2-Clause license.
25
26
27|Branch |Status |
28|------------|---------|
29|master | [![Build Status][travisMasterBadge]][travisLink] [![Build status][AppveyorMasterBadge]][AppveyorLink] [![coverity][coverBadge]][coverlink] |
30|dev | [![Build Status][travisDevBadge]][travisLink] [![Build status][AppveyorDevBadge]][AppveyorLink] |
31
32[travisMasterBadge]: https://travis-ci.org/lz4/lz4.svg?branch=master "Continuous Integration test suite"
33[travisDevBadge]: https://travis-ci.org/lz4/lz4.svg?branch=dev "Continuous Integration test suite"
34[travisLink]: https://travis-ci.org/lz4/lz4
35[AppveyorMasterBadge]: https://ci.appveyor.com/api/projects/status/github/lz4/lz4?branch=master&svg=true "Windows test suite"
36[AppveyorDevBadge]: https://ci.appveyor.com/api/projects/status/github/lz4/lz4?branch=dev&svg=true "Windows test suite"
37[AppveyorLink]: https://ci.appveyor.com/project/YannCollet/lz4-1lndh
38[coverBadge]: https://scan.coverity.com/projects/4735/badge.svg "Static code analysis of Master branch"
39[coverlink]: https://scan.coverity.com/projects/4735
40
41> **Branch Policy:**
42> - The "master" branch is considered stable, at all times.
43> - The "dev" branch is the one where all contributions must be merged
44 before being promoted to master.
45> + If you plan to propose a patch, please commit into the "dev" branch,
46 or its own feature branch.
47 Direct commit to "master" are not permitted.
48
49Benchmarks
50-------------------------
51
52The benchmark uses [lzbench], from @inikep
53compiled with GCC v8.2.0 on Linux 64-bits (Ubuntu 4.18.0-17).
54The reference system uses a Core i7-9700K CPU @ 4.9GHz (w/ turbo boost).
55Benchmark evaluates the compression of reference [Silesia Corpus]
56in single-thread mode.
57
58[lzbench]: https://github.com/inikep/lzbench
59[Silesia Corpus]: http://sun.aei.polsl.pl/~sdeor/index.php?page=silesia
60
61| Compressor | Ratio | Compression | Decompression |
62| ---------- | ----- | ----------- | ------------- |
63| memcpy | 1.000 | 13700 MB/s | 13700 MB/s |
64|**LZ4 default (v1.9.0)** |**2.101**| **780 MB/s**| **4970 MB/s** |
65| LZO 2.09 | 2.108 | 670 MB/s | 860 MB/s |
66| QuickLZ 1.5.0 | 2.238 | 575 MB/s | 780 MB/s |
67| Snappy 1.1.4 | 2.091 | 565 MB/s | 1950 MB/s |
68| [Zstandard] 1.4.0 -1 | 2.883 | 515 MB/s | 1380 MB/s |
69| LZF v3.6 | 2.073 | 415 MB/s | 910 MB/s |
70| [zlib] deflate 1.2.11 -1| 2.730 | 100 MB/s | 415 MB/s |
71|**LZ4 HC -9 (v1.9.0)** |**2.721**| 41 MB/s | **4900 MB/s** |
72| [zlib] deflate 1.2.11 -6| 3.099 | 36 MB/s | 445 MB/s |
73
74[zlib]: http://www.zlib.net/
75[Zstandard]: http://www.zstd.net/
76
77LZ4 is also compatible and optimized for x32 mode,
78for which it provides additional speed performance.
79
80
81Installation
82-------------------------
83
84```
85make
86make install # this command may require root permissions
87```
88
89LZ4's `Makefile` supports standard [Makefile conventions],
90including [staged installs], [redirection], or [command redefinition].
91It is compatible with parallel builds (`-j#`).
92
93[Makefile conventions]: https://www.gnu.org/prep/standards/html_node/Makefile-Conventions.html
94[staged installs]: https://www.gnu.org/prep/standards/html_node/DESTDIR.html
95[redirection]: https://www.gnu.org/prep/standards/html_node/Directory-Variables.html
96[command redefinition]: https://www.gnu.org/prep/standards/html_node/Utilities-in-Makefiles.html
97
98
99Documentation
100-------------------------
101
102The raw LZ4 block compression format is detailed within [lz4_Block_format].
103
104Arbitrarily long files or data streams are compressed using multiple blocks,
105for streaming requirements. These blocks are organized into a frame,
106defined into [lz4_Frame_format].
107Interoperable versions of LZ4 must also respect the frame format.
108
109[lz4_Block_format]: doc/lz4_Block_format.md
110[lz4_Frame_format]: doc/lz4_Frame_format.md
111
112
113Other source versions
114-------------------------
115
116Beyond the C reference source,
117many contributors have created versions of lz4 in multiple languages
118(Java, C#, Python, Perl, Ruby, etc.).
119A list of known source ports is maintained on the [LZ4 Homepage].
120
121[LZ4 Homepage]: http://www.lz4.org
122