look.c revision 95887 
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#include <sys/cdefs.h>
40__SCCSID("@(#)look.c	8.1 (Berkeley) 6/6/93");
41__RCSID_SOURCE("$OpenBSD: look.c,v 1.10 2002/04/26 16:15:16 espie Exp $");
42__FBSDID("$FreeBSD: head/usr.bin/m4/look.c 95887 2002-05-01 21:37:29Z jmallett $");
43
44/*
45 * look.c
46 * Facility: m4 macro processor
47 * by: oz
48 */
49
50#include <sys/types.h>
51#include <stdio.h>
52#include <stdlib.h>
53#include <stddef.h>
54#include <string.h>
55#include "mdef.h"
56#include "stdd.h"
57#include "extern.h"
58
59static void freent(ndptr);
60
61unsigned int
62hash(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(const char *name)
75{
76	ndptr p;
77	unsigned int h;
78
79	h = hash(name);
80	for (p = hashtab[h % HASHSIZE]; p != nil; p = p->nxtptr)
81		if (h == p->hv && STREQ(name, p->name))
82			break;
83	return (p);
84}
85
86/*
87 * hash and create an entry in the hash table.
88 * The new entry is added in front of a hash bucket.
89 */
90ndptr
91addent(const char *name)
92{
93	unsigned int h;
94	ndptr p;
95
96	h = hash(name);
97	p = (ndptr) xalloc(sizeof(struct ndblock));
98	p->nxtptr = hashtab[h % HASHSIZE];
99	hashtab[h % HASHSIZE] = p;
100	p->name = xstrdup(name);
101	p->hv = h;
102	return p;
103}
104
105static void
106freent(ndptr p)
107{
108	free((char *) p->name);
109	if (p->defn != null)
110		free((char *) p->defn);
111	free((char *) p);
112}
113
114/*
115 * remove an entry from the hashtable
116 */
117void
118remhash(const char *name, int all)
119{
120	unsigned int h;
121	ndptr xp, tp, mp;
122
123	h = hash(name);
124	mp = hashtab[h % HASHSIZE];
125	tp = nil;
126	while (mp != nil) {
127		if (mp->hv == h && STREQ(mp->name, name)) {
128			mp = mp->nxtptr;
129			if (tp == nil) {
130				freent(hashtab[h % HASHSIZE]);
131				hashtab[h % HASHSIZE] = mp;
132			}
133			else {
134				xp = tp->nxtptr;
135				tp->nxtptr = mp;
136				freent(xp);
137			}
138			if (!all)
139				break;
140		}
141		else {
142			tp = mp;
143			mp = mp->nxtptr;
144		}
145	}
146}
147