1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
|
/*-
* Copyright (c) 2013, Joseph Koshy
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* An implementation of the Fowler-Noll-Vo hash function.
*
* References:
* - http://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function
* - http://www.isthe.com/chongo/tech/comp/fnv/
*/
#include <sys/types.h>
#include <limits.h>
#include "_libelftc.h"
ELFTC_VCSID("$Id: libelftc_hash.c 2870 2013-01-07 10:38:43Z jkoshy $");
/*
* Use the size of an 'int' to determine the magic numbers used by the
* hash function.
*/
#if INT_MAX == 2147483647UL
#define FNV_PRIME 16777619UL
#define FNV_OFFSET 2166136261UL
#elif INT_MAX == 18446744073709551615ULL
#define FNV_PRIME 1099511628211ULL
#define FNV_OFFSET 14695981039346656037ULL
#else
#error sizeof(int) is unknown.
#endif
unsigned int
libelftc_hash_string(const char *s)
{
char c;
unsigned int hash;
for (hash = FNV_OFFSET; (c = *s) != '\0'; s++) {
hash ^= c;
hash *= FNV_PRIME;
}
return (hash);
}
|
