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/* $OpenBSD: ohash_do.c,v 1.3 2002/02/16 21:27:23 millert Exp $ */
/* ex:ts=8 sw=4:
*/
/*
* Copyright (c) 1999 Marc Espie.
*
* Code written for the OpenBSD project.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE OPENBSD PROJECT AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBSD
* PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "ohash_int.h"
static void ohash_resize(struct ohash *);
static void
ohash_resize(h)
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(h, i)
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(h, i)
struct ohash *h;
unsigned int i;
{
if (h->t[i].p == DELETED)
return NULL;
else
return (void *)h->t[i].p;
}
void *
ohash_insert(h, i, p)
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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