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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 also features an extremely fast decoder, with speed in multiple GB/s per core, typically reaching RAM speed limits on multi-core systems.

A high compression derivative, called LZ4_HC, is also provided. It trades CPU time for compression ratio.

BranchStatus
masterBuild Status Build status
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 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.

CompressorRatioCompressionDecompression
memcpy1.0004200 MB/s4200 MB/s
LZ4 fast (r129)1.607680 MB/s2220 MB/s
LZ4 (r129)2.101385 MB/s1850 MB/s
LZO 2.062.108350 MB/s510 MB/s
QuickLZ 1.5.1.b62.238320 MB/s380 MB/s
Snappy 1.1.02.091250 MB/s960 MB/s
zlib 1.2.8 -12.73059 MB/s250 MB/s
LZ4 HC (r129)2.72022 MB/s1830 MB/s
zlib 1.2.8 -63.09918 MB/s270 MB/s

The raw LZ4 block compression format is detailed within lz4_Block_format.

Compressing an arbitrarily long file or data stream requires multiple blocks. 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 too.