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look.c revision 1.10 
      1 /*	$NetBSD: look.c,v 1.10 2004/06/20 22:20:15 jmc Exp $	*/
      2 /*	$OpenBSD: look.c,v 1.8 2001/09/17 08:11:13 espie Exp $	*/
      3 
      4 /*
      5  * Copyright (c) 1989, 1993
      6  *	The Regents of the University of California.  All rights reserved.
      7  *
      8  * This code is derived from software contributed to Berkeley by
      9  * Ozan Yigit at York University.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  * 3. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #if HAVE_NBTOOL_CONFIG_H
     37 #include "nbtool_config.h"
     38 #endif
     39 
     40 #include <sys/cdefs.h>
     41 #if defined(__RCSID) && !defined(lint)
     42 #if 0
     43 static char sccsid[] = "@(#)look.c	8.1 (Berkeley) 6/6/93";
     44 #else
     45 __RCSID("$NetBSD: look.c,v 1.10 2004/06/20 22:20:15 jmc Exp $");
     46 #endif
     47 #endif /* not lint */
     48 
     49 /*
     50  * look.c
     51  * Facility: m4 macro processor
     52  * by: oz
     53  */
     54 
     55 #include <sys/types.h>
     56 #include <stdio.h>
     57 #include <stdlib.h>
     58 #include <stddef.h>
     59 #include <string.h>
     60 #include "mdef.h"
     61 #include "stdd.h"
     62 #include "extern.h"
     63 
     64 static void freent __P((ndptr));
     65 
     66 unsigned
     67 hash(name)
     68 	const char *name;
     69 {
     70 	unsigned int h = 0;
     71 	while (*name)
     72 		h = (h << 5) + h + *name++;
     73 	return (h);
     74 }
     75 
     76 /*
     77  * find name in the hash table
     78  */
     79 ndptr
     80 lookup(name)
     81 	const char *name;
     82 {
     83 	ndptr p;
     84 	unsigned int h;
     85 
     86 	h = hash(name);
     87 	for (p = hashtab[h % HASHSIZE]; p != nil; p = p->nxtptr)
     88 		if (h == p->hv && STREQ(name, p->name))
     89 			break;
     90 	return (p);
     91 }
     92 
     93 /*
     94  * hash and create an entry in the hash table.
     95  * The new entry is added in front of a hash bucket.
     96  */
     97 ndptr
     98 addent(name)
     99 	const char *name;
    100 {
    101 	unsigned int h;
    102 	ndptr p;
    103 
    104 	h = hash(name);
    105 	p = (ndptr) xalloc(sizeof(struct ndblock));
    106 	p->nxtptr = hashtab[h % HASHSIZE];
    107 	hashtab[h % HASHSIZE] = p;
    108 	p->name = xstrdup(name);
    109 	p->hv = h;
    110 	return p;
    111 }
    112 
    113 static void
    114 freent(p)
    115 	ndptr p;
    116 {
    117 	free((char *) p->name);
    118 	if (p->defn != null)
    119 		free((char *) p->defn);
    120 	free((char *) p);
    121 }
    122 
    123 /*
    124  * remove an entry from the hashtable
    125  */
    126 void
    127 remhash(name, all)
    128 	const char *name;
    129 	int all;
    130 {
    131 	unsigned int h;
    132 	ndptr xp, tp, mp;
    133 
    134 	h = hash(name);
    135 	mp = hashtab[h % HASHSIZE];
    136 	tp = nil;
    137 	while (mp != nil) {
    138 		if (mp->hv == h && STREQ(mp->name, name)) {
    139 			mp = mp->nxtptr;
    140 			if (tp == nil) {
    141 				freent(hashtab[h % HASHSIZE]);
    142 				hashtab[h % HASHSIZE] = mp;
    143 			}
    144 			else {
    145 				xp = tp->nxtptr;
    146 				tp->nxtptr = mp;
    147 				freent(xp);
    148 			}
    149 			if (!all)
    150 				break;
    151 		}
    152 		else {
    153 			tp = mp;
    154 			mp = mp->nxtptr;
    155 		}
    156 	}
    157 }
    158