source: git/src/hash.c @ ecbc6c18

RELEASE/1.1RELEASE/1.2debug-cidebug-ci-sanitisersstereowalls-data
Last change on this file since ecbc6c18 was ecbc6c18, checked in by Olly Betts <olly@…>, 14 years ago

src/: Update FSF address in licence notices.

git-svn-id: file:///home/survex-svn/survex/branches/survex-1_1@3417 4b37db11-9a0c-4f06-9ece-9ab7cdaee568

  • Property mode set to 100644
File size: 1.5 KB
Line 
1/* hash.c */
2/* String hashing function */
3/* Copyright (C) 1995-2002 Olly Betts
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
18 */
19
20#include <ctype.h>
21
22#include "debug.h"
23#include "hash.h"
24
25/* some (preferably prime) number for the hashing function */
26#define HASH_PRIME 29363
27
28int
29hash_string(const char *p)
30{
31   int hash;
32   SVX_ASSERT(p);
33   for (hash = 0; *p; p++)
34      hash = (hash * HASH_PRIME + *(const unsigned char*)p) & 0x7fff;
35   return hash;
36}
37
38int
39hash_lc_string(const char *p)
40{
41   int hash;
42   SVX_ASSERT(p);
43   for (hash = 0; *p; p++)
44      hash = (hash * HASH_PRIME + tolower(*(const unsigned char*)p)) & 0x7fff;
45   return hash;
46}
47
48int
49hash_data(const char *p, size_t len)
50{
51   int hash;
52   SVX_ASSERT(p);
53   for (hash = 0; len--; p++)
54      hash = (hash * HASH_PRIME + *(const unsigned char*)p) & 0x7fff;
55   return hash;
56}
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