112 lines
2.6 KiB
C
112 lines
2.6 KiB
C
/* $OpenBSD: ohash_do.c,v 1.4 2004/06/22 20:00:16 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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static void ohash_resize(struct ohash *);
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static void
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ohash_resize(struct ohash *h)
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{
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struct _ohash_record *n;
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unsigned int ns, j;
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unsigned int i, incr;
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if (4 * h->deleted < h->total)
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ns = h->size << 1;
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else if (3 * h->deleted > 2 * h->total)
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ns = h->size >> 1;
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else
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ns = h->size;
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if (ns < MINSIZE)
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ns = MINSIZE;
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#ifdef STATS_HASH
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STAT_HASH_EXPAND++;
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STAT_HASH_SIZE += ns - h->size;
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#endif
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n = (h->info.halloc)(sizeof(struct _ohash_record) * ns, h->info.data);
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if (!n)
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return;
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for (j = 0; j < h->size; j++) {
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if (h->t[j].p != NULL && h->t[j].p != DELETED) {
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i = h->t[j].hv % ns;
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incr = ((h->t[j].hv % (ns - 2)) & ~1) + 1;
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while (n[i].p != NULL) {
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i += incr;
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if (i >= ns)
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i -= ns;
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}
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n[i].hv = h->t[j].hv;
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n[i].p = h->t[j].p;
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}
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}
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(h->info.hfree)(h->t, sizeof(struct _ohash_record) * h->size,
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h->info.data);
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h->t = n;
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h->size = ns;
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h->total -= h->deleted;
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h->deleted = 0;
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}
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void *
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ohash_remove(struct ohash *h, unsigned int i)
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{
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void *result = __UNCONST(h->t[i].p);
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if (result == NULL || result == DELETED)
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return NULL;
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#ifdef STATS_HASH
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STAT_HASH_ENTRIES--;
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#endif
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h->t[i].p = DELETED;
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h->deleted++;
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if (h->deleted >= MINDELETED && 4 * h->deleted > h->total)
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ohash_resize(h);
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return result;
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}
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void *
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ohash_find(struct ohash *h, unsigned int i)
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{
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if (h->t[i].p == DELETED)
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return NULL;
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else
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return __UNCONST(h->t[i].p);
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}
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void *
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ohash_insert(struct ohash *h, unsigned int i, void *p)
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{
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#ifdef STATS_HASH
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STAT_HASH_ENTRIES++;
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#endif
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if (h->t[i].p == DELETED) {
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h->deleted--;
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h->t[i].p = p;
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} else {
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h->t[i].p = p;
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/* Arbitrary resize boundary. Tweak if not efficient enough. */
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if (++h->total * 4 > h->size * 3)
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ohash_resize(h);
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}
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return p;
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}
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