fd19c4eedf
* Small changes, for some reason VS 2015 can't link cprintf and they added a second function std::map::count and bind couldn't resolve the function. Substituted with a lambda-expression. * Created all 64bit version of the 3rd party libs. * Cleanup popup opens CleanupSettings instead of CleanupSettingsPane. Not finished, panel is wrong now (also uses CleanupSettings). * Tried to get Twain working, failed. * When there are more then 3 peg holes create additional holes. * When a hole touches the boundary it should still be considered a hole. * Do not compare dot size against fixed size. Will not work in some scan resolutions. Used the same value (PERCENT * max dot size) as later in the code in compare_dots. * When there are more than three peg holes the code looked for the best fit and used that. The problem was, that the middle hole was used as center for auto center. For three peg holes that is correct, but does not work for more than three. Now the best fit is calculated and from there the offset of the middle of the three best fit holes is calculated and applied. * One of the last changes broke VS2015 compatibility, it chocked on a missing include. * fix for msvs2013 * revert autopos.cpp * apply clang-format * use GIT-LFS |
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| .. | ||
| cmake_unofficial | ||
| contrib/djgpp | ||
| examples | ||
| lib | ||
| programs | ||
| versionsTest | ||
| visual/2012 | ||
| vs2010 | ||
| .travis.yml | ||
| lz4_32.lib | ||
| lz4_64.lib | ||
| lz4_Block_format.md | ||
| lz4_Frame_format.md | ||
| Makefile | ||
| NEWS | ||
| 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.
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 excellent decompression speed.
| 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 |
| 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.