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/*
* Copyright (c) 2008, 2009 Nicira Networks.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <config.h>
#include "hash.h"
#include <string.h>
/* Returns the hash of the 'n' 32-bit words at 'p', starting from 'basis'.
* 'p' must be properly aligned. */
uint32_t
hash_words(const uint32_t *p, size_t n, uint32_t basis)
{
uint32_t a, b, c;
a = b = c = 0xdeadbeef + (((uint32_t) n) << 2) + basis;
while (n > 3) {
a += p[0];
b += p[1];
c += p[2];
HASH_MIX(a, b, c);
n -= 3;
p += 3;
}
switch (n) {
case 3:
c += p[2];
/* fall through */
case 2:
b += p[1];
/* fall through */
case 1:
a += p[0];
HASH_FINAL(a, b, c);
/* fall through */
case 0:
break;
}
return c;
}
/* Returns the hash of the 'n' bytes at 'p', starting from 'basis'. */
uint32_t
hash_bytes(const void *p_, size_t n, uint32_t basis)
{
const uint8_t *p = p_;
uint32_t a, b, c;
uint32_t tmp[3];
a = b = c = 0xdeadbeef + n + basis;
while (n >= sizeof tmp) {
memcpy(tmp, p, sizeof tmp);
a += tmp[0];
b += tmp[1];
c += tmp[2];
HASH_MIX(a, b, c);
n -= sizeof tmp;
p += sizeof tmp;
}
if (n) {
tmp[0] = tmp[1] = tmp[2] = 0;
memcpy(tmp, p, n);
a += tmp[0];
b += tmp[1];
c += tmp[2];
HASH_FINAL(a, b, c);
}
return c;
}
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