Home | History | Annotate | Line # | Download | only in m4
look.c revision 1.1.1.1 
      1 /*
      2  * Copyright (c) 1989 The Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * This code is derived from software contributed to Berkeley by
      6  * Ozan Yigit.
      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
     38 static char sccsid[] = "@(#)look.c	5.3 (Berkeley) 2/26/91";
     39 #endif /* not lint */
     40 
     41 /*
     42  * look.c
     43  * Facility: m4 macro processor
     44  * by: oz
     45  */
     46 
     47 #include <stdio.h>
     48 #include <stdlib.h>
     49 #include <string.h>
     50 #include "mdef.h"
     51 #include "extr.h"
     52 
     53 /*
     54  *  hash - compute hash value using the proverbial
     55  *	   hashing function. Taken from K&R.
     56  */
     57 hash (name)
     58 register char *name;
     59 {
     60 	register int h = 0;
     61 	while (*name)
     62 		h += *name++;
     63 	return (h % HASHSIZE);
     64 }
     65 
     66 /*
     67  * lookup - find name in the hash table
     68  *
     69  */
     70 ndptr lookup(name)
     71 char *name;
     72 {
     73 	register ndptr p;
     74 
     75 	for (p = hashtab[hash(name)]; p != nil; p = p->nxtptr)
     76 		if (strcmp(name, p->name) == 0)
     77 			break;
     78 	return (p);
     79 }
     80 
     81 /*
     82  * addent - hash and create an entry in the hash
     83  *	    table. The new entry is added in front
     84  *	    of a hash bucket.
     85  */
     86 ndptr addent(name)
     87 char *name;
     88 {
     89 	register int h;
     90 	ndptr p;
     91 
     92 	h = hash(name);
     93 	if ((p = (ndptr) malloc(sizeof(struct ndblock))) != NULL) {
     94 		p->nxtptr = hashtab[h];
     95 		hashtab[h] = p;
     96 		p->name = strdup(name);
     97 	}
     98 	else
     99 		error("m4: no more memory.");
    100 	return p;
    101 }
    102 
    103 /*
    104  * remhash - remove an entry from the hashtable
    105  *
    106  */
    107 remhash(name, all)
    108 char *name;
    109 int all;
    110 {
    111 	register int h;
    112 	register ndptr xp, tp, mp;
    113 
    114 	h = hash(name);
    115 	mp = hashtab[h];
    116 	tp = nil;
    117 	while (mp != nil) {
    118 		if (strcmp(mp->name, name) == 0) {
    119 			mp = mp->nxtptr;
    120 			if (tp == nil) {
    121 				freent(hashtab[h]);
    122 				hashtab[h] = mp;
    123 			}
    124 			else {
    125 				xp = tp->nxtptr;
    126 				tp->nxtptr = mp;
    127 				freent(xp);
    128 			}
    129 			if (!all)
    130 				break;
    131 		}
    132 		else {
    133 			tp = mp;
    134 			mp = mp->nxtptr;
    135 		}
    136 	}
    137 }
    138 
    139 /*
    140  * freent - free a hashtable information block
    141  *
    142  */
    143 freent(p)
    144 ndptr p;
    145 {
    146 	if (!(p->type & STATIC)) {
    147 		free(p->name);
    148 		if (p->defn != null)
    149 			free(p->defn);
    150 	}
    151 	free(p);
    152 }
    153 
    154