69 lines
1.8 KiB
C
69 lines
1.8 KiB
C
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/* $OpenBSD: ohash_lookup_interval.c,v 1.3 2006/01/16 15:52:25 espie Exp $ */
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/* ex:ts=8 sw=4:
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*/
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/* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "ohash_int.h"
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unsigned int
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ohash_lookup_interval(struct ohash *h, const char *start, const char *end,
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uint32_t hv)
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{
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unsigned int i, incr;
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unsigned int empty;
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#ifdef STATS_HASH
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STAT_HASH_LOOKUP++;
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#endif
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empty = NONE;
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i = hv % h->size;
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incr = ((hv % (h->size-2)) & ~1) + 1;
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while (h->t[i].p != NULL) {
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#ifdef STATS_HASH
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STAT_HASH_LENGTH++;
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#endif
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if (h->t[i].p == DELETED) {
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if (empty == NONE)
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empty = i;
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} else if (h->t[i].hv == hv &&
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strncmp(h->t[i].p+h->info.key_offset, start,
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end - start) == 0 &&
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(h->t[i].p+h->info.key_offset)[end-start] == '\0') {
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if (empty != NONE) {
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h->t[empty].hv = hv;
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h->t[empty].p = h->t[i].p;
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h->t[i].p = DELETED;
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return empty;
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} else {
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#ifdef STATS_HASH
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STAT_HASH_POSITIVE++;
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#endif
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return i;
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}
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}
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i += incr;
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if (i >= h->size)
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i -= h->size;
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}
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/* Found an empty position. */
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if (empty != NONE)
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i = empty;
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h->t[i].hv = hv;
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return i;
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}
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