| commit | d05ca2ff6d7ea79ad1426c6cb3f5260ec8af26b9 | [log] [download] |
|---|---|---|
| author | Yann Collet <cyan@fb.com> | Tue Nov 01 16:54:33 2016 -0700 |
| committer | Yann Collet <cyan@fb.com> | Tue Nov 01 16:54:33 2016 -0700 |
| tree | a7c798aef17b0c0182b2d3f600a6e0fc3006e699 | |
| parent | 7e112cfa5cd3dfb6d6df97e31c5d68bff4ec0713 [diff] |
fixed #247, reported by Felix Bolte
- .gitattributes
- .gitignore
- .travis.yml
- Makefile
- NEWS
- README.md
- appveyor.yml
- cmake_unofficial/
- contrib/djgpp/
- debian/
- examples/
- lib/
- lz4_Block_format.md
- lz4_Frame_format.md
- programs/
- versionsTest/
- visual/
LZ4 - Extremely fast compression
LZ4 is lossless compression algorithm, providing compression speed at 400 MB/s per core, scalable with multi-cores CPU. It features an extremely fast decoder, with speed in multiple GB/s per core, typically reaching RAM speed limits on multi-core systems.
Speed can be tuned dynamically, selecting an “acceleration” factor which trades compression ratio for more speed up. On the other end, a high compression derivative, LZ4_HC, is also provided, trading CPU time for improved compression ratio. All versions feature the same decompression speed.
LZ4 library is provided as open-source software using BSD license.
| Branch | Status |
|---|---|
| master |   |
| dev |  |
Branch Policy:
- The “master” branch is considered stable, at all times.
- The “dev” branch is the one where all contributions must be merged before being promoted to master.
- If you plan to propose a patch, please commit into the “dev” branch, or its own feature branch. Direct commit to “master” are not permitted.
Benchmarks
The benchmark uses the Open-Source Benchmark program by m^2 (v0.14.3) compiled with GCC v4.8.2 on Linux Mint 64-bits v17. The reference system uses a Core i5-4300U @1.9GHz. Benchmark evaluates the compression of reference Silesia Corpus in single-thread mode.
| Compressor | Ratio | Compression | Decompression |
|---|---|---|---|
| memcpy | 1.000 | 4200 MB/s | 4200 MB/s |
| LZ4 fast 17 (r129) | 1.607 | 690 MB/s | 2220 MB/s |
| LZ4 default (r129) | 2.101 | 385 MB/s | 1850 MB/s |
| LZO 2.06 | 2.108 | 350 MB/s | 510 MB/s |
| QuickLZ 1.5.1.b6 | 2.238 | 320 MB/s | 380 MB/s |
| Snappy 1.1.0 | 2.091 | 250 MB/s | 960 MB/s |
| Zstandard 0.5.1 | 2.876 | 240 MB/s | 620 MB/s |
| LZF v3.6 | 2.073 | 175 MB/s | 500 MB/s |
| zlib 1.2.8 -1 | 2.730 | 59 MB/s | 250 MB/s |
| LZ4 HC (r129) | 2.720 | 22 MB/s | 1830 MB/s |
| zlib 1.2.8 -6 | 3.099 | 18 MB/s | 270 MB/s |
Documentation
The raw LZ4 block compression format is detailed within lz4_Block_format.
To compress an arbitrarily long file or data stream, multiple blocks are required. Organizing these blocks and providing a common header format to handle their content is the purpose of the Frame format, defined into lz4_Frame_format. Interoperable versions of LZ4 must respect this frame format.
Other source versions
Beyond the C reference source, many contributors have created versions of lz4 in multiple languages (Java, C#, Python, Perl, Ruby, etc.). A list of known source ports is maintained on the LZ4 Homepage.