hash.c revision 91587 
1/*	$NetBSD: hash.c,v 1.7 2002/01/21 19:49:52 tv Exp $	*/
2
3/*
4 * Copyright (c) 1994, 1995 Jochen Pohl
5 * All Rights Reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *      This product includes software developed by Jochen Pohl for
18 *	The NetBSD Project.
19 * 4. The name of the author may not be used to endorse or promote products
20 *    derived from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35#if defined(__RCSID) && !defined(lint)
36__RCSID("$NetBSD: hash.c,v 1.7 2002/01/21 19:49:52 tv Exp $");
37#endif
38
39/*
40 * XXX Really need a generalized hash table package
41 */
42
43#include <limits.h>
44#include <stddef.h>
45#include <stdlib.h>
46#include <string.h>
47
48#include "lint2.h"
49
50/* pointer to hash table, initialized in inithash() */
51static	hte_t	**htab;
52
53static	int	hash(const char *);
54
55/*
56 * Initialize hash table.
57 */
58void
59_inithash(hte_t ***tablep)
60{
61
62	if (tablep == NULL)
63		tablep = &htab;
64
65	*tablep = xcalloc(HSHSIZ2, sizeof (hte_t *));
66}
67
68/*
69 * Compute hash value from a string.
70 */
71static int
72hash(const char *s)
73{
74	u_int	v;
75	const	u_char *us;
76
77	v = 0;
78	for (us = (const u_char *)s; *us != '\0'; us++) {
79		v = (v << sizeof (v)) + *us;
80		v ^= v >> (sizeof (v) * CHAR_BIT - sizeof (v));
81	}
82	return (v % HSHSIZ2);
83}
84
85/*
86 * Look for a hash table entry. If no hash table entry for the
87 * given name exists and mknew is set, create a new one.
88 */
89hte_t *
90_hsearch(hte_t **table, const char *s, int mknew)
91{
92	int	h;
93	hte_t	*hte;
94
95	if (table == NULL)
96		table = htab;
97
98	h = hash(s);
99	for (hte = table[h]; hte != NULL; hte = hte->h_link) {
100		if (strcmp(hte->h_name, s) == 0)
101			break;
102	}
103
104	if (hte != NULL || !mknew)
105		return (hte);
106
107	/* create a new hte */
108	hte = xmalloc(sizeof (hte_t));
109	hte->h_name = xstrdup(s);
110	hte->h_used = 0;
111	hte->h_def = 0;
112	hte->h_static = 0;
113	hte->h_syms = NULL;
114	hte->h_lsym = &hte->h_syms;
115	hte->h_calls = NULL;
116	hte->h_lcall = &hte->h_calls;
117	hte->h_usyms = NULL;
118	hte->h_lusym = &hte->h_usyms;
119	hte->h_link = table[h];
120	hte->h_hte = NULL;
121	table[h] = hte;
122
123	return (hte);
124}
125
126/*
127 * Call function f for each name in the hash table.
128 */
129void
130_forall(hte_t **table, void (*f)(hte_t *))
131{
132	int	i;
133	hte_t	*hte;
134
135	if (table == NULL)
136		table = htab;
137
138	for (i = 0; i < HSHSIZ2; i++) {
139		for (hte = table[i]; hte != NULL; hte = hte->h_link)
140			(*f)(hte);
141	}
142}
143
144/*
145 * Free all contents of the hash table that this module allocated.
146 */
147void
148_destroyhash(hte_t **table)
149{
150	int	i;
151	hte_t	*hte, *nexthte;
152
153	if (table == NULL)
154		err(1, "_destroyhash called on main hash table");
155
156	for (i = 0; i < HSHSIZ2; i++) {
157		for (hte = table[i]; hte != NULL; hte = nexthte) {
158			free((void *)hte->h_name);
159			nexthte = hte->h_link;
160			free(hte);
161		}
162	}
163	free(table);
164}
165