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/*-
* Copyright (c) 1982, 1986, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
/*
* General routine to allocate a hash table with control of memory flags.
*/
void *
hashinit_flags(int elements, struct malloc_type *type, u_long *hashmask,
int flags)
{
long hashsize;
LIST_HEAD(generic, generic) *hashtbl;
int i;
KASSERT(elements > 0, ("%s: bad elements", __func__));
/* Exactly one of HASH_WAITOK and HASH_NOWAIT must be set. */
KASSERT((flags & HASH_WAITOK) ^ (flags & HASH_NOWAIT),
("Bad flags (0x%x) passed to hashinit_flags", flags));
for (hashsize = 1; hashsize <= elements; hashsize <<= 1)
continue;
hashsize >>= 1;
if (flags & HASH_NOWAIT)
hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl),
type, M_NOWAIT);
else
hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl),
type, M_WAITOK);
if (hashtbl != NULL) {
for (i = 0; i < hashsize; i++)
LIST_INIT(&hashtbl[i]);
*hashmask = hashsize - 1;
}
return (hashtbl);
}
/*
* Allocate and initialize a hash table with default flag: may sleep.
*/
void *
hashinit(int elements, struct malloc_type *type, u_long *hashmask)
{
return (hashinit_flags(elements, type, hashmask, HASH_WAITOK));
}
void
hashdestroy(void *vhashtbl, struct malloc_type *type, u_long hashmask)
{
LIST_HEAD(generic, generic) *hashtbl, *hp;
hashtbl = vhashtbl;
for (hp = hashtbl; hp <= &hashtbl[hashmask]; hp++)
KASSERT(LIST_EMPTY(hp), ("%s: hash not empty", __func__));
free(hashtbl, type);
}
static const int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531,
2039, 2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143,
6653, 7159, 7673, 8191, 12281, 16381, 24571, 32749 };
#define NPRIMES (sizeof(primes) / sizeof(primes[0]))
/*
* General routine to allocate a prime number sized hash table.
*/
void *
phashinit(int elements, struct malloc_type *type, u_long *nentries)
{
long hashsize;
LIST_HEAD(generic, generic) *hashtbl;
int i;
KASSERT(elements > 0, ("%s: bad elements", __func__));
for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
i++;
if (i == NPRIMES)
break;
hashsize = primes[i];
}
hashsize = primes[i - 1];
hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
for (i = 0; i < hashsize; i++)
LIST_INIT(&hashtbl[i]);
*nentries = hashsize;
return (hashtbl);
}
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