look.c revision 1590 
1/*
2 * Copyright (c) 1989, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Ozan Yigit at York University.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#ifndef lint
38static char sccsid[] = "@(#)look.c	8.1 (Berkeley) 6/6/93";
39#endif /* not lint */
40
41/*
42 * look.c
43 * Facility: m4 macro processor
44 * by: oz
45 */
46
47#include <sys/types.h>
48#include <stdio.h>
49#include <stdlib.h>
50#include <string.h>
51#include "mdef.h"
52#include "stdd.h"
53#include "extern.h"
54
55int
56hash(name)
57register char *name;
58{
59	register unsigned long h = 0;
60	while (*name)
61		h = (h << 5) + h + *name++;
62	return (h % HASHSIZE);
63}
64
65/*
66 * find name in the hash table
67 */
68ndptr
69lookup(name)
70char *name;
71{
72	register ndptr p;
73
74	for (p = hashtab[hash(name)]; p != nil; p = p->nxtptr)
75		if (STREQ(name, p->name))
76			break;
77	return (p);
78}
79
80/*
81 * hash and create an entry in the hash table.
82 * The new entry is added in front of a hash bucket.
83 */
84ndptr
85addent(name)
86char *name;
87{
88	register int h;
89	ndptr p;
90
91	h = hash(name);
92	p = (ndptr) xalloc(sizeof(struct ndblock));
93	p->nxtptr = hashtab[h];
94	hashtab[h] = p;
95	p->name = xstrdup(name);
96	return p;
97}
98
99static void
100freent(p)
101ndptr p;
102{
103	if (!(p->type & STATIC)) {
104		free((char *) p->name);
105		if (p->defn != null)
106			free((char *) p->defn);
107	}
108	free((char *) p);
109}
110
111/*
112 * remove an entry from the hashtable
113 */
114void
115remhash(name, all)
116char *name;
117int all;
118{
119	register int h;
120	register ndptr xp, tp, mp;
121
122	h = hash(name);
123	mp = hashtab[h];
124	tp = nil;
125	while (mp != nil) {
126		if (STREQ(mp->name, name)) {
127			mp = mp->nxtptr;
128			if (tp == nil) {
129				freent(hashtab[h]);
130				hashtab[h] = mp;
131			}
132			else {
133				xp = tp->nxtptr;
134				tp->nxtptr = mp;
135				freent(xp);
136			}
137			if (!all)
138				break;
139		}
140		else {
141			tp = mp;
142			mp = mp->nxtptr;
143		}
144	}
145}
146