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/*
* Copyright (c) 2008, 2009 Nicira Networks.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef HASH_H
#define HASH_H 1
#include <stddef.h>
#include <stdint.h>
#include <string.h>
/* This is the public domain lookup3 hash by Bob Jenkins from
* http://burtleburtle.net/bob/c/lookup3.c, modified for style. */
#define HASH_ROT(x, k) (((x) << (k)) | ((x) >> (32 - (k))))
#define HASH_MIX(a, b, c) \
do { \
a -= c; a ^= HASH_ROT(c, 4); c += b; \
b -= a; b ^= HASH_ROT(a, 6); a += c; \
c -= b; c ^= HASH_ROT(b, 8); b += a; \
a -= c; a ^= HASH_ROT(c, 16); c += b; \
b -= a; b ^= HASH_ROT(a, 19); a += c; \
c -= b; c ^= HASH_ROT(b, 4); b += a; \
} while (0)
#define HASH_FINAL(a, b, c) \
do { \
c ^= b; c -= HASH_ROT(b, 14); \
a ^= c; a -= HASH_ROT(c, 11); \
b ^= a; b -= HASH_ROT(a, 25); \
c ^= b; c -= HASH_ROT(b, 16); \
a ^= c; a -= HASH_ROT(c, 4); \
b ^= a; b -= HASH_ROT(a, 14); \
c ^= b; c -= HASH_ROT(b, 24); \
} while (0)
uint32_t hash_words(const uint32_t *, size_t n_word, uint32_t basis);
uint32_t hash_bytes(const void *, size_t n_bytes, uint32_t basis);
static inline uint32_t hash_string(const char *s, uint32_t basis)
{
return hash_bytes(s, strlen(s), basis);
}
/* This is Bob Jenkins' integer hash from
* http://burtleburtle.net/bob/hash/integer.html, modified for style. */
static inline uint32_t hash_int(uint32_t x, uint32_t basis)
{
x -= x << 6;
x ^= x >> 17;
x -= x << 9;
x ^= x << 4;
x -= x << 3;
x ^= x << 10;
x ^= x >> 15;
return x + basis;
}
#endif /* hash.h */
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