1 /*- 2 * Copyright (c) 1982, 1986, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/malloc.h> 43 44 /* 45 * General routine to allocate a hash table with control of memory flags. 46 */ 47 void * 48 hashinit_flags(int elements, struct malloc_type *type, u_long *hashmask, 49 int flags) 50 { 51 long hashsize; 52 LIST_HEAD(generic, generic) *hashtbl; 53 int i; 54 55 KASSERT(elements > 0, ("%s: bad elements", __func__)); 56 /* Exactly one of HASH_WAITOK and HASH_NOWAIT must be set. */ 57 KASSERT((flags & HASH_WAITOK) ^ (flags & HASH_NOWAIT), 58 ("Bad flags (0x%x) passed to hashinit_flags", flags)); 59 60 for (hashsize = 1; hashsize <= elements; hashsize <<= 1) 61 continue; 62 hashsize >>= 1; 63 64 if (flags & HASH_NOWAIT) 65 hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), 66 type, M_NOWAIT); 67 else 68 hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), 69 type, M_WAITOK); 70 71 if (hashtbl != NULL) { 72 for (i = 0; i < hashsize; i++) 73 LIST_INIT(&hashtbl[i]); 74 *hashmask = hashsize - 1; 75 } 76 return (hashtbl); 77 } 78 79 /* 80 * Allocate and initialize a hash table with default flag: may sleep. 81 */ 82 void * 83 hashinit(int elements, struct malloc_type *type, u_long *hashmask) 84 { 85 86 return (hashinit_flags(elements, type, hashmask, HASH_WAITOK)); 87 } 88 89 void 90 hashdestroy(void *vhashtbl, struct malloc_type *type, u_long hashmask) 91 { 92 LIST_HEAD(generic, generic) *hashtbl, *hp; 93 94 hashtbl = vhashtbl; 95 for (hp = hashtbl; hp <= &hashtbl[hashmask]; hp++) 96 KASSERT(LIST_EMPTY(hp), ("%s: hash not empty", __func__)); 97 free(hashtbl, type); 98 } 99 100 static const int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 101 2039, 2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 102 6653, 7159, 7673, 8191, 12281, 16381, 24571, 32749 }; 103 #define NPRIMES (sizeof(primes) / sizeof(primes[0])) 104 105 /* 106 * General routine to allocate a prime number sized hash table. 107 */ 108 void * 109 phashinit(int elements, struct malloc_type *type, u_long *nentries) 110 { 111 long hashsize; 112 LIST_HEAD(generic, generic) *hashtbl; 113 int i; 114 115 KASSERT(elements > 0, ("%s: bad elements", __func__)); 116 for (i = 1, hashsize = primes[1]; hashsize <= elements;) { 117 i++; 118 if (i == NPRIMES) 119 break; 120 hashsize = primes[i]; 121 } 122 hashsize = primes[i - 1]; 123 hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK); 124 for (i = 0; i < hashsize; i++) 125 LIST_INIT(&hashtbl[i]); 126 *nentries = hashsize; 127 return (hashtbl); 128 } 129