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/* $OpenBSD: ohash_lookup_interval.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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "ohash_int.h"
unsigned int
ohash_lookup_interval(struct ohash *h, const char *start, const char *end,
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 &&
strncmp(h->t[i].p+h->info.key_offset, start,
end - start) == 0 &&
(h->t[i].p+h->info.key_offset)[end-start] == '\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;
}
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