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src.rivoreo.one / lz4 / b89cac7b2e92b792af98bb0a12e4d14684d07629
commitb89cac7b2e92b792af98bb0a12e4d14684d07629[log] [download]
authorEric Siegerman <pub08-git@davor.org>Tue Feb 14 14:17:06 2017 -0500
committerEric Siegerman <pub08-git@davor.org>Tue Feb 14 14:17:06 2017 -0500
tree61839b45c434b67fdcc849dc998305c093b5f129
parent7e57c398c1b23f1631f690e0154ee4bee98e5f71 [diff]
Don't use "foo && false || true"

Replace it with either:
    test ! -f $FILE_THAT_SHOULD_NOT_EXIST
or:
    ! $COMMAND_THAT_SHOULD_FAIL

as appropriate.
1 file changed
tree: 61839b45c434b67fdcc849dc998305c093b5f129
  1. .gitattributes
  2. .gitignore
  3. .travis.yml
  4. LICENSE
  5. Makefile
  6. NEWS
  7. README.md
  8. appveyor.yml
  9. contrib/
  10. doc/
  11. examples/
  12. lib/
  13. programs/
  14. tests/
  15. visual/
README.md

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 2-Clause license.

BranchStatus
masterBuild Status Build status coverity
devBuild Status Build status

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 lzbench, from @inikep compiled with GCC v6.2.0 on Linux 64-bits. The reference system uses a Core i7-3930K CPU @ 4.5GHz. Benchmark evaluates the compression of reference Silesia Corpus in single-thread mode.

CompressorRatioCompressionDecompression
memcpy1.0007300 MB/s7300 MB/s
LZ4 fast 8 (v1.7.3)1.799911 MB/s3360 MB/s
LZ4 default (v1.7.3)2.101625 MB/s3220 MB/s
LZO 2.092.108620 MB/s845 MB/s
QuickLZ 1.5.02.238510 MB/s600 MB/s
Snappy 1.1.32.091450 MB/s1550 MB/s
LZF v3.62.073365 MB/s820 MB/s
Zstandard 1.1.1 -12.876330 MB/s930 MB/s
Zstandard 1.1.1 -33.164200 MB/s810 MB/s
zlib deflate 1.2.8 -12.730100 MB/s370 MB/s
LZ4 HC -9 (v1.7.3)2.72034 MB/s3240 MB/s
zlib deflate 1.2.8 -63.09933 MB/s390 MB/s

LZ4 is also compatible and well optimized for x32 mode, for which it provides +10% speed performance.

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.