| 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 | [](https://travis-ci.org/Cyan4973/lz4) | |
| |dev | [](https://travis-ci.org/Cyan4973/lz4) | |
| |visual | [](https://ci.appveyor.com/project/YannCollet/lz4) | |
| |
| |
| |
| > **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 tests 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 | |
| |**LZ4 fast (r129)**| 1.607 |**680 MB/s** | **2220 MB/s** | |
| |**LZ4 (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 | |
| | 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 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. |
| |
| [Open-Source Benchmark program by m^2 (v0.14.3)]: http://encode.ru/threads/1371-Filesystem-benchmark?p=34029&viewfull=1#post34029 |
| [Silesia Corpus]: http://sun.aei.polsl.pl/~sdeor/index.php?page=silesia |
| [lz4_Block_format]: lz4_Block_format.md |
| [lz4_Frame_format]: lz4_Frame_format.md |