hash.c revision 12099 
1/*	$NetBSD: hash.c,v 1.2 1995/07/03 21:24:47 cgd 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#ifndef lint
35static char rcsid[] = "$NetBSD: hash.c,v 1.2 1995/07/03 21:24:47 cgd Exp $";
36#endif
37
38#include <stddef.h>
39#include <string.h>
40#include <limits.h>
41
42#include "lint2.h"
43
44/* pointer to hash table, initialized in inithash() */
45static	hte_t	**htab;
46
47static	int	hash __P((const char *));
48
49/*
50 * Initialize hash table.
51 */
52void
53inithash()
54{
55	htab = xcalloc(HSHSIZ2, sizeof (hte_t *));
56}
57
58/*
59 * Compute hash value from a string.
60 */
61static int
62hash(s)
63	const	char *s;
64{
65	u_int	v;
66	const	u_char *us;
67
68	v = 0;
69	for (us = (const u_char *)s; *us != '\0'; us++) {
70		v = (v << sizeof (v)) + *us;
71		v ^= v >> (sizeof (v) * CHAR_BIT - sizeof (v));
72	}
73	return (v % HSHSIZ2);
74}
75
76/*
77 * Look for a hash table entry. If no hash table entry for the
78 * given name exists and mknew is set, create a new one.
79 */
80hte_t *
81hsearch(s, mknew)
82	const	char *s;
83	int	mknew;
84{
85	int	h;
86	hte_t	*hte;
87
88	h = hash(s);
89	for (hte = htab[h]; hte != NULL; hte = hte->h_link) {
90		if (strcmp(hte->h_name, s) == 0)
91			break;
92	}
93
94	if (hte != NULL || !mknew)
95		return (hte);
96
97	/* create a new hte */
98	hte = xalloc(sizeof (hte_t));
99	hte->h_name = xstrdup(s);
100	hte->h_lsym = &hte->h_syms;
101	hte->h_lcall = &hte->h_calls;
102	hte->h_lusym = &hte->h_usyms;
103	hte->h_link = htab[h];
104	htab[h] = hte;
105
106	return (hte);
107}
108
109/*
110 * Call function f for each name in the hash table.
111 */
112void
113forall(f)
114	void	(*f) __P((hte_t *));
115{
116	int	i;
117	hte_t	*hte;
118
119	for (i = 0; i < HSHSIZ2; i++) {
120		for (hte = htab[i]; hte != NULL; hte = hte->h_link)
121			(*f)(hte);
122	}
123}
124