1 /* $OpenBSD: ohash_do.c,v 1.4 2004/06/22 20:00:16 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_do.c,v 1.2 2012/11/17 01:54:24 svnexp Exp $ 20 */ 21 22 #include "ohash_int.h" 23 24 static void ohash_resize(struct ohash *); 25 26 static void 27 ohash_resize(struct ohash *h) 28 { 29 struct _ohash_record *n; 30 unsigned int ns, j; 31 unsigned int i, incr; 32 33 if (4 * h->deleted < h->total) 34 ns = h->size << 1; 35 else if (3 * h->deleted > 2 * h->total) 36 ns = h->size >> 1; 37 else 38 ns = h->size; 39 if (ns < MINSIZE) 40 ns = MINSIZE; 41 #ifdef STATS_HASH 42 STAT_HASH_EXPAND++; 43 STAT_HASH_SIZE += ns - h->size; 44 #endif 45 n = (h->info.halloc)(sizeof(struct _ohash_record) * ns, h->info.data); 46 if (n == NULL) 47 return; 48 49 for (j = 0; j < h->size; j++) { 50 if (h->t[j].p != NULL && h->t[j].p != DELETED) { 51 i = h->t[j].hv % ns; 52 incr = ((h->t[j].hv % (ns - 2)) & ~1) + 1; 53 while (n[i].p != NULL) { 54 i += incr; 55 if (i >= ns) 56 i -= ns; 57 } 58 n[i].hv = h->t[j].hv; 59 n[i].p = h->t[j].p; 60 } 61 } 62 (h->info.hfree)(h->t, sizeof(struct _ohash_record) * h->size, 63 h->info.data); 64 h->t = n; 65 h->size = ns; 66 h->total -= h->deleted; 67 h->deleted = 0; 68 } 69 70 void * 71 ohash_remove(struct ohash *h, unsigned int i) 72 { 73 void *result = __DECONST(void *, h->t[i].p); 74 75 if (result == NULL || result == DELETED) 76 return NULL; 77 78 #ifdef STATS_HASH 79 STAT_HASH_ENTRIES--; 80 #endif 81 h->t[i].p = DELETED; 82 h->deleted++; 83 if (h->deleted >= MINDELETED && 4 * h->deleted > h->total) 84 ohash_resize(h); 85 return result; 86 } 87 88 void * 89 ohash_find(struct ohash *h, unsigned int i) 90 { 91 if (h->t[i].p == DELETED) 92 return NULL; 93 else 94 return __DECONST(void *, h->t[i].p); 95 } 96 97 void * 98 ohash_insert(struct ohash *h, unsigned int i, void *p) 99 { 100 #ifdef STATS_HASH 101 STAT_HASH_ENTRIES++; 102 #endif 103 if (h->t[i].p == DELETED) { 104 h->deleted--; 105 h->t[i].p = p; 106 } else { 107 h->t[i].p = p; 108 /* Arbitrary resize boundary. Tweak if not efficient enough. */ 109 if (++h->total * 4 > h->size * 3) 110 ohash_resize(h); 111 } 112 return p; 113 } 114