| xxHash - Extremely fast hash algorithm |
| ====================================== |
| |
| xxHash is an Extremely fast Hash algorithm, running at RAM speed limits. |
| It successfully completes the [SMHasher](http://code.google.com/p/smhasher/wiki/SMHasher) test suite |
| which evaluates collision, dispersion and randomness qualities of hash functions. |
| |
| |Branch |Status | |
| |------------|---------| |
| |master | [](https://travis-ci.org/Cyan4973/xxHash?branch=master) | |
| |dev | [](https://travis-ci.org/Cyan4973/xxHash?branch=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 SMHasher speed test, compiled with Visual 2010 on a Windows Seven 32-bits box. |
| The reference system uses a Core 2 Duo @3GHz |
| |
| |
| | Name | Speed | Quality | Author | |
| |---------------|----------|:-------:|------------------| |
| | [xxHash] | 5.4 GB/s | 10 | Y.C. | |
| | MurmurHash 3a | 2.7 GB/s | 10 | Austin Appleby | |
| | SBox | 1.4 GB/s | 9 | Bret Mulvey | |
| | Lookup3 | 1.2 GB/s | 9 | Bob Jenkins | |
| | CityHash64 | 1.05 GB/s| 10 | Pike & Alakuijala| |
| | FNV | 0.55 GB/s| 5 | Fowler, Noll, Vo | |
| | CRC32 | 0.43 GB/s| 9 | | |
| | MD5-32 | 0.33 GB/s| 10 | Ronald L.Rivest | |
| | SHA1-32 | 0.28 GB/s| 10 | | |
| |
| [xxHash]: http://www.xxhash.com |
| |
| Q.Score is a measure of quality of the hash function. |
| It depends on successfully passing SMHasher test set. |
| 10 is a perfect score. |
| Algorithms with a score < 5 are not listed on this table. |
| |
| A new version, XXH64, has been created thanks to [Mathias Westerdahl]'s contribution, |
| which offers superior speed and dispersion for 64-bits systems. |
| Note however that 32-bits applications will still run faster using the 32-bits version. |
| [Mathias Westerdahl]: https://github.com/JCash |
| |
| SMHasher speed test, compiled using GCC 4.8.2, on Linux Mint 64-bits. |
| The reference system uses a Core i5-3340M @2.7GHz |
| |
| | Version | Speed on 64-bits | Speed on 32-bits | |
| |------------|------------------|------------------| |
| | XXH64 | 13.8 GB/s | 1.9 GB/s | |
| | XXH32 | 6.8 GB/s | 6.0 GB/s | |
| |
| |
| ### License |
| |
| The library files `xxhash.c` and `xxhash.h` are BSD licensed. |
| The utility `xxhsum` is GPL licensed. |
| |
| |
| ### Other languages |
| |
| Beyond the C reference version, |
| xxHash is also available on many programming languages, |
| thanks to great contributors. |
| They are [listed here](http://www.xxhash.com/#other-languages). |
| |
