| // city.h - cityhash-c |
| // CityHash on C |
| // Copyright (c) 2011-2012, Alexander Nusov |
| // |
| // - original copyright notice - |
| // Copyright (c) 2011 Google, Inc. |
| // |
| // Permission is hereby granted, free of charge, to any person obtaining a copy |
| // of this software and associated documentation files (the "Software"), to deal |
| // in the Software without restriction, including without limitation the rights |
| // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| // copies of the Software, and to permit persons to whom the Software is |
| // furnished to do so, subject to the following conditions: |
| // |
| // The above copyright notice and this permission notice shall be included in |
| // all copies or substantial portions of the Software. |
| // |
| // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| // THE SOFTWARE. |
| // |
| // CityHash, by Geoff Pike and Jyrki Alakuijala |
| // |
| // This file provides a few functions for hashing strings. On x86-64 |
| // hardware in 2011, CityHash64() is faster than other high-quality |
| // hash functions, such as Murmur. This is largely due to higher |
| // instruction-level parallelism. CityHash64() and CityHash128() also perform |
| // well on hash-quality tests. |
| // |
| // CityHash128() is optimized for relatively long strings and returns |
| // a 128-bit hash. For strings more than about 2000 bytes it can be |
| // faster than CityHash64(). |
| // |
| // Functions in the CityHash family are not suitable for cryptography. |
| // |
| // WARNING: This code has not been tested on big-endian platforms! |
| // It is known to work well on little-endian platforms that have a small penalty |
| // for unaligned reads, such as current Intel and AMD moderate-to-high-end CPUs. |
| // |
| // By the way, for some hash functions, given strings a and b, the hash |
| // of a+b is easily derived from the hashes of a and b. This property |
| // doesn't hold for any hash functions in this file. |
| |
| #ifndef CITY_HASH_H_ |
| #define CITY_HASH_H_ |
| |
| #include <stdlib.h> |
| #include <stdint.h> |
| |
| typedef uint8_t uint8; |
| typedef uint32_t uint32; |
| typedef uint64_t uint64; |
| |
| typedef struct _uint128 uint128; |
| struct _uint128 { |
| uint64 first; |
| uint64 second; |
| }; |
| |
| #define Uint128Low64(x) (x).first |
| #define Uint128High64(x) (x).second |
| |
| // Hash function for a byte array. |
| uint64 CityHash64(const char *buf, size_t len); |
| |
| // Hash function for a byte array. For convenience, a 64-bit seed is also |
| // hashed into the result. |
| uint64 CityHash64WithSeed(const char *buf, size_t len, uint64 seed); |
| |
| // Hash function for a byte array. For convenience, two seeds are also |
| // hashed into the result. |
| uint64 CityHash64WithSeeds(const char *buf, size_t len, uint64 seed0, |
| uint64 seed1); |
| |
| // Hash function for a byte array. |
| uint128 CityHash128(const char *s, size_t len); |
| |
| // Hash function for a byte array. For convenience, a 128-bit seed is also |
| // hashed into the result. |
| uint128 CityHash128WithSeed(const char *s, size_t len, uint128 seed); |
| |
| #endif // CITY_HASH_H_ |