mirror of
https://github.com/openvswitch/ovs
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72 lines
2.5 KiB
C
72 lines
2.5 KiB
C
/*
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* Copyright (c) 2008, 2009 Nicira Networks.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#ifndef HASH_H
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#define HASH_H 1
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#include <stddef.h>
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#include <stdint.h>
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#include <string.h>
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/* This is the public domain lookup3 hash by Bob Jenkins from
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* http://burtleburtle.net/bob/c/lookup3.c, modified for style. */
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#define HASH_ROT(x, k) (((x) << (k)) | ((x) >> (32 - (k))))
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#define HASH_MIX(a, b, c) \
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do { \
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a -= c; a ^= HASH_ROT(c, 4); c += b; \
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b -= a; b ^= HASH_ROT(a, 6); a += c; \
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c -= b; c ^= HASH_ROT(b, 8); b += a; \
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a -= c; a ^= HASH_ROT(c, 16); c += b; \
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b -= a; b ^= HASH_ROT(a, 19); a += c; \
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c -= b; c ^= HASH_ROT(b, 4); b += a; \
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} while (0)
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#define HASH_FINAL(a, b, c) \
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do { \
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c ^= b; c -= HASH_ROT(b, 14); \
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a ^= c; a -= HASH_ROT(c, 11); \
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b ^= a; b -= HASH_ROT(a, 25); \
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c ^= b; c -= HASH_ROT(b, 16); \
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a ^= c; a -= HASH_ROT(c, 4); \
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b ^= a; b -= HASH_ROT(a, 14); \
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c ^= b; c -= HASH_ROT(b, 24); \
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} while (0)
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uint32_t hash_words(const uint32_t *, size_t n_word, uint32_t basis);
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uint32_t hash_bytes(const void *, size_t n_bytes, uint32_t basis);
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static inline uint32_t hash_string(const char *s, uint32_t basis)
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{
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return hash_bytes(s, strlen(s), basis);
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}
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/* This is Bob Jenkins' integer hash from
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* http://burtleburtle.net/bob/hash/integer.html, modified for style. */
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static inline uint32_t hash_int(uint32_t x, uint32_t basis)
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{
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x -= x << 6;
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x ^= x >> 17;
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x -= x << 9;
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x ^= x << 4;
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x -= x << 3;
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x ^= x << 10;
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x ^= x >> 15;
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return x + basis;
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}
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#endif /* hash.h */
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