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 */
47void *
48hashinit_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 */
82void *
83hashinit(int elements, struct malloc_type *type, u_long *hashmask)
84{
85
86	return (hashinit_flags(elements, type, hashmask, HASH_WAITOK));
87}
88
89void
90hashdestroy(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
100static 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 */
108void *
109phashinit(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