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lookup.c revision 1.1 
      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[] = "@(#)lookup.c	5.5 (Berkeley) 6/1/90";
     36 #endif /* not lint */
     37 
     38 #include "defs.h"
     39 
     40 	/* symbol types */
     41 #define VAR	1
     42 #define CONST	2
     43 
     44 struct syment {
     45 	int	s_type;
     46 	char	*s_name;
     47 	struct	namelist *s_value;
     48 	struct	syment *s_next;
     49 };
     50 
     51 static struct syment *hashtab[HASHSIZE];
     52 
     53 /*
     54  * Define a variable from a command line argument.
     55  */
     56 define(name)
     57 	char *name;
     58 {
     59 	register char *cp, *s;
     60 	register struct namelist *nl;
     61 	struct namelist *value;
     62 
     63 	if (debug)
     64 		printf("define(%s)\n", name);
     65 
     66 	cp = index(name, '=');
     67 	if (cp == NULL)
     68 		value = NULL;
     69 	else if (cp[1] == '\0') {
     70 		*cp = '\0';
     71 		value = NULL;
     72 	} else if (cp[1] != '(') {
     73 		*cp++ = '\0';
     74 		value = makenl(cp);
     75 	} else {
     76 		nl = NULL;
     77 		*cp++ = '\0';
     78 		do
     79 			cp++;
     80 		while (*cp == ' ' || *cp == '\t');
     81 		for (s = cp; ; s++) {
     82 			switch (*s) {
     83 			case ')':
     84 				*s = '\0';
     85 			case '\0':
     86 				break;
     87 			case ' ':
     88 			case '\t':
     89 				*s++ = '\0';
     90 				while (*s == ' ' || *s == '\t')
     91 					s++;
     92 				if (*s == ')')
     93 					*s = '\0';
     94 				break;
     95 			default:
     96 				continue;
     97 			}
     98 			if (nl == NULL)
     99 				value = nl = makenl(cp);
    100 			else {
    101 				nl->n_next = makenl(cp);
    102 				nl = nl->n_next;
    103 			}
    104 			if (*s == '\0')
    105 				break;
    106 			cp = s;
    107 		}
    108 	}
    109 	(void) lookup(name, REPLACE, value);
    110 }
    111 
    112 /*
    113  * Lookup name in the table and return a pointer to it.
    114  * LOOKUP - just do lookup, return NULL if not found.
    115  * INSERT - insert name with value, error if already defined.
    116  * REPLACE - insert or replace name with value.
    117  */
    118 
    119 struct namelist *
    120 lookup(name, action, value)
    121 	char *name;
    122 	int action;
    123 	struct namelist *value;
    124 {
    125 	register unsigned n;
    126 	register char *cp;
    127 	register struct syment *s;
    128 	char buf[256];
    129 
    130 	if (debug)
    131 		printf("lookup(%s, %d, %x)\n", name, action, value);
    132 
    133 	n = 0;
    134 	for (cp = name; *cp; )
    135 		n += *cp++;
    136 	n %= HASHSIZE;
    137 
    138 	for (s = hashtab[n]; s != NULL; s = s->s_next) {
    139 		if (strcmp(name, s->s_name))
    140 			continue;
    141 		if (action != LOOKUP) {
    142 			if (action != INSERT || s->s_type != CONST) {
    143 				(void)sprintf(buf, "%s redefined", name);
    144 				yyerror(buf);
    145 			}
    146 		}
    147 		return(s->s_value);
    148 	}
    149 
    150 	if (action == LOOKUP) {
    151 		(void)sprintf(buf, "%s undefined", name);
    152 		yyerror(buf);
    153 		return(NULL);
    154 	}
    155 
    156 	s = ALLOC(syment);
    157 	if (s == NULL)
    158 		fatal("ran out of memory\n");
    159 	s->s_next = hashtab[n];
    160 	hashtab[n] = s;
    161 	s->s_type = action == INSERT ? VAR : CONST;
    162 	s->s_name = name;
    163 	s->s_value = value;
    164 	return(value);
    165 }
    166