54 lines
1.4 KiB
C
54 lines
1.4 KiB
C
/* $Id$ */
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/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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/* s y m t a b . c
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*
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* Contains the routine findident, which builds the symbol table and
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* searches identifiers
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*/
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#include <stdlib.h>
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#include <string.h>
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#include "symtab.h"
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struct symtab *idtable, *deftable;
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struct symtab *
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findident(s, mode, table) char *s; struct symtab **table; {
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/*
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* Look for identifier s in the symboltable referred to by *table.
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* If mode = LOOKING, no new entry's will be made.
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* If mode = ENTERING, a new entry will be made if s is not in the
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* table yet, otherwise an error results
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*/
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register struct symtab *p;
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register n;
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if (!*table) { /* No entry for this symbol */
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if (mode == LOOKING) return (struct symtab *) 0;
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/*
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* Make new entry
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*/
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p = (struct symtab *) malloc(sizeof *p);
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p->s_left = p->s_right = (struct symtab *) 0;
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p->s_name = malloc( (unsigned) (strlen(s) + 1));
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strcpy(p->s_name,s);
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*table = p;
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return p;
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}
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else {
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p = *table;
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if ((n = strcmp(p->s_name,s)) == 0) { /* This is it! */
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if (mode == ENTERING) {
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error("Identifier %s redefined",s);
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}
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return p;
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}
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/* Binary tree ..... */
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if (n < 0) return findident(s,mode,&(p->s_left));
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return findident(s,mode,&(p->s_right));
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}
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/* NOTREACHED */
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}
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