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
22unsigned int
23ohash_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