1 /*
2  * libdpkg - Debian packaging suite library routines
3  * strhash.c - FNV string hashing support
4  *
5  * Copyright © 2003 Daniel Silverstone <dsilvers@digital-scurf.org>
6  *
7  * This is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
19  */
20 
21 #include <config.h>
22 #include <compat.h>
23 
24 #include <dpkg/string.h>
25 
26 #define FNV_OFFSET_BASIS 2166136261UL
27 #define FNV_MIXING_PRIME 16777619UL
28 
29 /**
30  * Fowler/Noll/Vo -- FNV-1a simple string hash.
31  *
32  * For more info, @see <http://www.isthe.com/chongo/tech/comp/fnv/index.html>.
33  *
34  * @param str The string to hash.
35  *
36  * @return The hashed value.
37  */
38 unsigned int
str_fnv_hash(const char * str)39 str_fnv_hash(const char *str)
40 {
41 	register unsigned int h = FNV_OFFSET_BASIS;
42 	register unsigned int p = FNV_MIXING_PRIME;
43 
44 	while (*str) {
45 		h ^= *str++;
46 		h *= p;
47 	}
48 
49 	return h;
50 }
51