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