1 /* $OpenBSD: ohash_lookup_interval.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 * $FreeBSD: src/usr.bin/m4/lib/ohash_lookup_interval.c,v 1.2 2012/11/17 01:54:24 svnexp Exp $ 20 */ 21 22 #include "ohash_int.h" 23 24 unsigned int 25 ohash_lookup_interval(struct ohash *h, const char *start, const char *end, 26 uint32_t hv) 27 { 28 unsigned int i, incr; 29 unsigned int empty; 30 31 #ifdef STATS_HASH 32 STAT_HASH_LOOKUP++; 33 #endif 34 empty = NONE; 35 i = hv % h->size; 36 incr = ((hv % (h->size-2)) & ~1) + 1; 37 while (h->t[i].p != NULL) { 38 #ifdef STATS_HASH 39 STAT_HASH_LENGTH++; 40 #endif 41 if (h->t[i].p == DELETED) { 42 if (empty == NONE) 43 empty = i; 44 } else if (h->t[i].hv == hv && 45 strncmp(h->t[i].p+h->info.key_offset, start, 46 end - start) == 0 && 47 (h->t[i].p+h->info.key_offset)[end-start] == '\0') { 48 if (empty != NONE) { 49 h->t[empty].hv = hv; 50 h->t[empty].p = h->t[i].p; 51 h->t[i].p = DELETED; 52 return empty; 53 } else { 54 #ifdef STATS_HASH 55 STAT_HASH_POSITIVE++; 56 #endif 57 return i; 58 } 59 } 60 i += incr; 61 if (i >= h->size) 62 i -= h->size; 63 } 64 65 /* Found an empty position. */ 66 if (empty != NONE) 67 i = empty; 68 h->t[i].hv = hv; 69 return i; 70 } 71