1 /* $OpenBSD: ohash_lookup_memory.c,v 1.3 2006/01/16 15:52:25 espie Exp $ */
2 /* ex:ts=8 sw=4:
3 */
4
5 /* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org>
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20 #include "ohash_int.h"
21
22 unsigned int
ohash_lookup_memory(struct ohash * h,const char * k,size_t size,uint32_t hv)23 ohash_lookup_memory(struct ohash *h, const char *k, size_t size, uint32_t hv)
24 {
25 unsigned int i, incr;
26 unsigned int empty;
27
28 #ifdef STATS_HASH
29 STAT_HASH_LOOKUP++;
30 #endif
31 empty = NONE;
32 i = hv % h->size;
33 incr = ((hv % (h->size-2)) & ~1) + 1;
34 while (h->t[i].p != NULL) {
35 #ifdef STATS_HASH
36 STAT_HASH_LENGTH++;
37 #endif
38 if (h->t[i].p == DELETED) {
39 if (empty == NONE)
40 empty = i;
41 } else if (h->t[i].hv == hv &&
42 memcmp(h->t[i].p+h->info.key_offset, k, size) == 0) {
43 if (empty != NONE) {
44 h->t[empty].hv = hv;
45 h->t[empty].p = h->t[i].p;
46 h->t[i].p = DELETED;
47 return empty;
48 } else {
49 #ifdef STATS_HASH
50 STAT_HASH_POSITIVE++;
51 #endif
52 } return i;
53 }
54 i += incr;
55 if (i >= h->size)
56 i -= h->size;
57 }
58
59 /* Found an empty position. */
60 if (empty != NONE)
61 i = empty;
62 h->t[i].hv = hv;
63 return i;
64 }
65