ntirpc/misc/city.h

/* 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_ */