93a1b4c4cf
hashdestroy() since in absence of INVARIANTS a compiler will drop the entire for() cycle.
129 lines
4.2 KiB
C
129 lines
4.2 KiB
C
/*-
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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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* 4. 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 8.3 (Berkeley) 1/21/94
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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/*
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* General routine to allocate a hash table with control of memory flags.
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*/
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void *
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hashinit_flags(int elements, struct malloc_type *type, u_long *hashmask,
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int flags)
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{
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long hashsize;
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LIST_HEAD(generic, generic) *hashtbl;
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int i;
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KASSERT(elements > 0, ("%s: bad elements", __func__));
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/* Exactly one of HASH_WAITOK and HASH_NOWAIT must be set. */
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KASSERT((flags & HASH_WAITOK) ^ (flags & HASH_NOWAIT),
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("Bad flags (0x%x) passed to hashinit_flags", flags));
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for (hashsize = 1; hashsize <= elements; hashsize <<= 1)
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continue;
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hashsize >>= 1;
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if (flags & HASH_NOWAIT)
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hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl),
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type, M_NOWAIT);
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else
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hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl),
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type, M_WAITOK);
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if (hashtbl != NULL) {
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for (i = 0; i < hashsize; i++)
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LIST_INIT(&hashtbl[i]);
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*hashmask = hashsize - 1;
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}
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return (hashtbl);
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}
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/*
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* Allocate and initialize a hash table with default flag: may sleep.
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*/
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void *
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hashinit(int elements, struct malloc_type *type, u_long *hashmask)
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{
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return (hashinit_flags(elements, type, hashmask, HASH_WAITOK));
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}
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void
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hashdestroy(void *vhashtbl, struct malloc_type *type, u_long hashmask)
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{
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LIST_HEAD(generic, generic) *hashtbl, *hp;
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hashtbl = vhashtbl;
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for (hp = hashtbl; hp <= &hashtbl[hashmask]; hp++)
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KASSERT(LIST_EMPTY(hp), ("%s: hash not empty", __func__));
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free(hashtbl, type);
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}
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static const int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531,
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2039, 2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143,
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6653, 7159, 7673, 8191, 12281, 16381, 24571, 32749 };
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#define NPRIMES (sizeof(primes) / sizeof(primes[0]))
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/*
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* General routine to allocate a prime number sized hash table.
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*/
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void *
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phashinit(int elements, struct malloc_type *type, u_long *nentries)
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{
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long hashsize;
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LIST_HEAD(generic, generic) *hashtbl;
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int i;
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KASSERT(elements > 0, ("%s: bad elements", __func__));
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for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
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i++;
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if (i == NPRIMES)
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break;
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hashsize = primes[i];
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}
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hashsize = primes[i - 1];
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hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
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for (i = 0; i < hashsize; i++)
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LIST_INIT(&hashtbl[i]);
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*nentries = hashsize;
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return (hashtbl);
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}
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