/* $OpenBSD: ohash_lookup_memory.c,v 1.3 2006/01/16 15:52:25 espie Exp $ */
/* ex:ts=8 sw=4:
 */

/* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * $FreeBSD: src/usr.bin/m4/lib/ohash_lookup_memory.c,v 1.2 2012/11/17 01:54:24 svnexp Exp $
 */

#include "ohash_int.h"

unsigned int
ohash_lookup_memory(struct ohash *h, const char *k, size_t size, uint32_t hv)
{
        unsigned int    i, incr;
        unsigned int    empty;

#ifdef STATS_HASH
        STAT_HASH_LOOKUP++;
#endif
        empty = NONE;
        i = hv % h->size;
        incr = ((hv % (h->size-2)) & ~1) + 1;
        while (h->t[i].p != NULL) {
#ifdef STATS_HASH
                STAT_HASH_LENGTH++;
#endif
                if (h->t[i].p == DELETED) {
                        if (empty == NONE)
                                empty = i;
                } else if (h->t[i].hv == hv &&
                    memcmp(h->t[i].p+h->info.key_offset, k, size) == 0) {
                        if (empty != NONE) {
                                h->t[empty].hv = hv;
                                h->t[empty].p = h->t[i].p;
                                h->t[i].p = DELETED;
                                return empty;
                        } else {
#ifdef STATS_HASH
                                STAT_HASH_POSITIVE++;
#endif
                        }
                        return i;
                }
                i += incr;
                if (i >= h->size)
                        i -= h->size;
        }

        /* Found an empty position. */
        if (empty != NONE)
                i = empty;
        h->t[i].hv = hv;
        return i;
}