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lookup.c revision 1.2 
      1 /*
      2  * Copyright (c) 1983 Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #ifndef lint
     35 /*static char sccsid[] = "from: @(#)lookup.c	5.5 (Berkeley) 6/1/90";*/
     36 static char rcsid[] = "$Id: lookup.c,v 1.2 1993/08/01 18:09:43 mycroft Exp $";
     37 #endif /* not lint */
     38 
     39 #include "defs.h"
     40 
     41 	/* symbol types */
     42 #define VAR	1
     43 #define CONST	2
     44 
     45 struct syment {
     46 	int	s_type;
     47 	char	*s_name;
     48 	struct	namelist *s_value;
     49 	struct	syment *s_next;
     50 };
     51 
     52 static struct syment *hashtab[HASHSIZE];
     53 
     54 /*
     55  * Define a variable from a command line argument.
     56  */
     57 define(name)
     58 	char *name;
     59 {
     60 	register char *cp, *s;
     61 	register struct namelist *nl;
     62 	struct namelist *value;
     63 
     64 	if (debug)
     65 		printf("define(%s)\n", name);
     66 
     67 	cp = index(name, '=');
     68 	if (cp == NULL)
     69 		value = NULL;
     70 	else if (cp[1] == '\0') {
     71 		*cp = '\0';
     72 		value = NULL;
     73 	} else if (cp[1] != '(') {
     74 		*cp++ = '\0';
     75 		value = makenl(cp);
     76 	} else {
     77 		nl = NULL;
     78 		*cp++ = '\0';
     79 		do
     80 			cp++;
     81 		while (*cp == ' ' || *cp == '\t');
     82 		for (s = cp; ; s++) {
     83 			switch (*s) {
     84 			case ')':
     85 				*s = '\0';
     86 			case '\0':
     87 				break;
     88 			case ' ':
     89 			case '\t':
     90 				*s++ = '\0';
     91 				while (*s == ' ' || *s == '\t')
     92 					s++;
     93 				if (*s == ')')
     94 					*s = '\0';
     95 				break;
     96 			default:
     97 				continue;
     98 			}
     99 			if (nl == NULL)
    100 				value = nl = makenl(cp);
    101 			else {
    102 				nl->n_next = makenl(cp);
    103 				nl = nl->n_next;
    104 			}
    105 			if (*s == '\0')
    106 				break;
    107 			cp = s;
    108 		}
    109 	}
    110 	(void) lookup(name, REPLACE, value);
    111 }
    112 
    113 /*
    114  * Lookup name in the table and return a pointer to it.
    115  * LOOKUP - just do lookup, return NULL if not found.
    116  * INSERT - insert name with value, error if already defined.
    117  * REPLACE - insert or replace name with value.
    118  */
    119 
    120 struct namelist *
    121 lookup(name, action, value)
    122 	char *name;
    123 	int action;
    124 	struct namelist *value;
    125 {
    126 	register unsigned n;
    127 	register char *cp;
    128 	register struct syment *s;
    129 	char buf[256];
    130 
    131 	if (debug)
    132 		printf("lookup(%s, %d, %x)\n", name, action, value);
    133 
    134 	n = 0;
    135 	for (cp = name; *cp; )
    136 		n += *cp++;
    137 	n %= HASHSIZE;
    138 
    139 	for (s = hashtab[n]; s != NULL; s = s->s_next) {
    140 		if (strcmp(name, s->s_name))
    141 			continue;
    142 		if (action != LOOKUP) {
    143 			if (action != INSERT || s->s_type != CONST) {
    144 				(void)sprintf(buf, "%s redefined", name);
    145 				yyerror(buf);
    146 			}
    147 		}
    148 		return(s->s_value);
    149 	}
    150 
    151 	if (action == LOOKUP) {
    152 		(void)sprintf(buf, "%s undefined", name);
    153 		yyerror(buf);
    154 		return(NULL);
    155 	}
    156 
    157 	s = ALLOC(syment);
    158 	if (s == NULL)
    159 		fatal("ran out of memory\n");
    160 	s->s_next = hashtab[n];
    161 	hashtab[n] = s;
    162 	s->s_type = action == INSERT ? VAR : CONST;
    163 	s->s_name = name;
    164 	s->s_value = value;
    165 	return(value);
    166 }
    167