look.c revision 95982 
1/*	$OpenBSD: look.c,v 1.10 2002/04/26 16:15:16 espie Exp $	*/
2
3/*
4 * Copyright (c) 1989, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Ozan Yigit at York University.
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 * 3. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *	This product includes software developed by the University of
21 *	California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 *    may be used to endorse or promote products derived from this software
24 *    without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39#if 0
40#ifndef lint
41static char sccsid[] = "@(#)look.c	8.1 (Berkeley) 6/6/93";
42#endif /* not lint */
43#endif
44
45#include <sys/cdefs.h>
46__FBSDID("$FreeBSD: head/usr.bin/m4/look.c 95982 2002-05-03 14:48:21Z jmallett $");
47
48/*
49 * look.c
50 * Facility: m4 macro processor
51 * by: oz
52 */
53
54#include <sys/types.h>
55#include <stdio.h>
56#include <stdlib.h>
57#include <stddef.h>
58#include <string.h>
59#include "mdef.h"
60#include "stdd.h"
61#include "extern.h"
62
63static void freent(ndptr);
64
65unsigned int
66hash(const char *name)
67{
68	unsigned int h = 0;
69	while (*name)
70		h = (h << 5) + h + *name++;
71	return (h);
72}
73
74/*
75 * find name in the hash table
76 */
77ndptr
78lookup(const char *name)
79{
80	ndptr p;
81	unsigned int h;
82
83	h = hash(name);
84	for (p = hashtab[h % HASHSIZE]; p != nil; p = p->nxtptr)
85		if (h == p->hv && STREQ(name, p->name))
86			break;
87	return (p);
88}
89
90/*
91 * hash and create an entry in the hash table.
92 * The new entry is added in front of a hash bucket.
93 */
94ndptr
95addent(const char *name)
96{
97	unsigned int h;
98	ndptr p;
99
100	h = hash(name);
101	p = (ndptr) xalloc(sizeof(struct ndblock));
102	p->nxtptr = hashtab[h % HASHSIZE];
103	hashtab[h % HASHSIZE] = p;
104	p->name = xstrdup(name);
105	p->hv = h;
106	return p;
107}
108
109static void
110freent(ndptr p)
111{
112	free((char *) p->name);
113	if (p->defn != null)
114		free((char *) p->defn);
115	free((char *) p);
116}
117
118/*
119 * remove an entry from the hashtable
120 */
121void
122remhash(const char *name, int all)
123{
124	unsigned int h;
125	ndptr xp, tp, mp;
126
127	h = hash(name);
128	mp = hashtab[h % HASHSIZE];
129	tp = nil;
130	while (mp != nil) {
131		if (mp->hv == h && STREQ(mp->name, name)) {
132			mp = mp->nxtptr;
133			if (tp == nil) {
134				freent(hashtab[h % HASHSIZE]);
135				hashtab[h % HASHSIZE] = mp;
136			}
137			else {
138				xp = tp->nxtptr;
139				tp->nxtptr = mp;
140				freent(xp);
141			}
142			if (!all)
143				break;
144		}
145		else {
146			tp = mp;
147			mp = mp->nxtptr;
148		}
149	}
150}
151