Current Path : /sys/kern/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
Current File : //sys/kern/subr_hash.c |
/*- * 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: release/9.1.0/sys/kern/subr_hash.c 231587 2012-02-13 15:21:12Z glebius $"); #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); }