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.

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. Direct commit to "master" are not permitted.
• Feature branches can also exist, for dedicated testing of larger modifications before merge into "dev" branch.

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
RLE64 v3.0	1.029	2800 MB/s	2800 MB/s
density -c1	1.592	700 MB/s	920 MB/s
LZ4 fast (r129)	1.595	680 MB/s	2220 MB/s
LZ4 (r129)	2.101	385 MB/s	1850 MB/s
density -c2	2.083	370 MB/s	505 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
density -c3	2.370	190 MB/s	185 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

The LZ4 block compression format is detailed within lz4_Block_format.

For streaming unknown amount of data and compress files of any size, a frame format has been published, and can be consulted within the file LZ4_Frame_Format.html .