look.c revision 95060 
1/*	$OpenBSD: look.c,v 1.9 2002/02/16 21:27:48 millert 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#include <sys/cdefs.h>
40__SCCSID("@(#)look.c      8.1 (Berkeley) 6/6/93");
41__FBSDID("$FreeBSD: head/usr.bin/m4/look.c 95060 2002-04-19 17:26:21Z jmallett $");
42
43/*
44 * look.c
45 * Facility: m4 macro processor
46 * by: oz
47 */
48
49#include <sys/types.h>
50#include <stdio.h>
51#include <stdlib.h>
52#include <stddef.h>
53#include <string.h>
54#include "mdef.h"
55#include "stdd.h"
56#include "extern.h"
57
58static void freent(ndptr);
59
60unsigned
61hash(name)
62	const char *name;
63{
64	unsigned int h = 0;
65	while (*name)
66		h = (h << 5) + h + *name++;
67	return (h);
68}
69
70/*
71 * find name in the hash table
72 */
73ndptr
74lookup(name)
75	const char *name;
76{
77	ndptr p;
78	unsigned int h;
79
80	h = hash(name);
81	for (p = hashtab[h % HASHSIZE]; p != nil; p = p->nxtptr)
82		if (h == p->hv && STREQ(name, p->name))
83			break;
84	return (p);
85}
86
87/*
88 * hash and create an entry in the hash table.
89 * The new entry is added in front of a hash bucket.
90 */
91ndptr
92addent(name)
93	const char *name;
94{
95	unsigned int h;
96	ndptr p;
97
98	h = hash(name);
99	p = (ndptr) xalloc(sizeof(struct ndblock));
100	p->nxtptr = hashtab[h % HASHSIZE];
101	hashtab[h % HASHSIZE] = p;
102	p->name = xstrdup(name);
103	p->hv = h;
104	return p;
105}
106
107static void
108freent(p)
109	ndptr p;
110{
111	free((char *) p->name);
112	if (p->defn != null)
113		free((char *) p->defn);
114	free((char *) p);
115}
116
117/*
118 * remove an entry from the hashtable
119 */
120void
121remhash(name, all)
122	const char *name;
123	int all;
124{
125	unsigned int h;
126	ndptr xp, tp, mp;
127
128	h = hash(name);
129	mp = hashtab[h % HASHSIZE];
130	tp = nil;
131	while (mp != nil) {
132		if (mp->hv == h && STREQ(mp->name, name)) {
133			mp = mp->nxtptr;
134			if (tp == nil) {
135				freent(hashtab[h % HASHSIZE]);
136				hashtab[h % HASHSIZE] = mp;
137			}
138			else {
139				xp = tp->nxtptr;
140				tp->nxtptr = mp;
141				freent(xp);
142			}
143			if (!all)
144				break;
145		}
146		else {
147			tp = mp;
148			mp = mp->nxtptr;
149		}
150	}
151}
152