133 lines
4.1 KiB
C
133 lines
4.1 KiB
C
/* $NetBSD: subr_hash.c,v 1.3 2008/05/05 17:11:17 ad Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)kern_subr.c 8.4 (Berkeley) 2/14/95
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: subr_hash.c,v 1.3 2008/05/05 17:11:17 ad Exp $");
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#include <sys/param.h>
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#include <sys/kmem.h>
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#include <sys/systm.h>
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/*
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* General routine to allocate a hash table.
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* Allocate enough memory to hold at least `elements' list-head pointers.
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* Return a pointer to the allocated space and set *hashmask to a pattern
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* suitable for masking a value to use as an index into the returned array.
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*/
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void *
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hashinit(u_int elements, enum hashtype htype, bool waitok, u_long *hashmask)
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{
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u_long hashsize, i;
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LIST_HEAD(, generic) *hashtbl_list;
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SLIST_HEAD(, generic) *hashtbl_slist;
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TAILQ_HEAD(, generic) *hashtbl_tailq;
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size_t esize;
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void *p;
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if (elements == 0)
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panic("hashinit: bad cnt");
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for (hashsize = 1; hashsize < elements; hashsize <<= 1)
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continue;
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switch (htype) {
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case HASH_LIST:
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esize = sizeof(*hashtbl_list);
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break;
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case HASH_SLIST:
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esize = sizeof(*hashtbl_slist);
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break;
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case HASH_TAILQ:
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esize = sizeof(*hashtbl_tailq);
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break;
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default:
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panic("hashinit: invalid table type");
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}
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p = kmem_alloc(hashsize * esize, (waitok ? KM_SLEEP : KM_NOSLEEP));
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if (p == NULL)
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return (NULL);
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switch (htype) {
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case HASH_LIST:
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hashtbl_list = p;
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for (i = 0; i < hashsize; i++)
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LIST_INIT(&hashtbl_list[i]);
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break;
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case HASH_SLIST:
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hashtbl_slist = p;
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for (i = 0; i < hashsize; i++)
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SLIST_INIT(&hashtbl_slist[i]);
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break;
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case HASH_TAILQ:
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hashtbl_tailq = p;
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for (i = 0; i < hashsize; i++)
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TAILQ_INIT(&hashtbl_tailq[i]);
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break;
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}
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*hashmask = hashsize - 1;
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return (p);
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}
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/*
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* Free memory from hash table previosly allocated via hashinit().
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*/
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void
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hashdone(void *hashtbl, enum hashtype htype, u_long hashmask)
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{
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LIST_HEAD(, generic) *hashtbl_list;
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SLIST_HEAD(, generic) *hashtbl_slist;
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TAILQ_HEAD(, generic) *hashtbl_tailq;
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size_t esize;
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switch (htype) {
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case HASH_LIST:
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esize = sizeof(*hashtbl_list);
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break;
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case HASH_SLIST:
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esize = sizeof(*hashtbl_slist);
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break;
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case HASH_TAILQ:
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esize = sizeof(*hashtbl_tailq);
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break;
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default:
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panic("hashdone: invalid table type");
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}
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kmem_free(hashtbl, esize * (hashmask + 1));
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}
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