ltl2ba-nix/lex.c

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/***** ltl2ba : lex.c *****/
/* Written by Denis Oddoux, LIAFA, France */
/* Copyright (c) 2001 Denis Oddoux */
/* Modified by Paul Gastin, LSV, France */
/* Copyright (c) 2007 Paul Gastin */
/* */
/* This program is free software; you can redistribute it and/or modify */
/* it under the terms of the GNU General Public License as published by */
/* the Free Software Foundation; either version 2 of the License, or */
/* (at your option) any later version. */
/* */
/* This program is distributed in the hope that it will be useful, */
/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
/* GNU General Public License for more details. */
/* */
/* You should have received a copy of the GNU General Public License */
/* along with this program; if not, write to the Free Software */
/* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA*/
/* */
/* Based on the translation algorithm by Gastin and Oddoux, */
/* presented at the 13th International Conference on Computer Aided */
/* Verification, CAV 2001, Paris, France. */
/* Proceedings - LNCS 2102, pp. 53-65 */
/* */
/* Send bug-reports and/or questions to Paul Gastin */
/* http://www.lsv.ens-cachan.fr/~gastin */
/* */
/* Some of the code in this file was taken from the Spin software */
/* Written by Gerard J. Holzmann, Bell Laboratories, U.S.A. */
#include <stdlib.h>
#include <ctype.h>
#include "ltl2ba.h"
static Symbol *symtab[Nhash+1];
static int tl_lex(void);
int (*tl_yylex)() = tl_lex;
extern YYSTYPE tl_yylval;
static char yytext[2048];
#define Token(y) tl_yylval = tl_nn(y,ZN,ZN); return y
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static int
isalnum_(int c)
{ return (isalnum(c) || c == '_');
}
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static int
hash(char *s)
{ int h=0;
while (*s)
{ h += *s++;
h <<= 1;
if (h&(Nhash+1))
h |= 1;
}
return h&Nhash;
}
static void
getword(int first, int (*tst)(int))
{ int i=0; char c;
yytext[i++]= (char ) first;
while (tst(c = tl_Getchar()))
yytext[i++] = c;
yytext[i] = '\0';
tl_UnGetchar();
}
static int
follow(int tok, int ifyes, int ifno)
{ int c;
char buf[32];
extern int tl_yychar;
if ((c = tl_Getchar()) == tok)
return ifyes;
tl_UnGetchar();
tl_yychar = c;
sprintf(buf, "expected '%c'", tok);
tl_yyerror(buf); /* no return from here */
return ifno;
}
static int
tl_lex(void)
{ int c;
do {
c = tl_Getchar();
yytext[0] = (char ) c;
yytext[1] = '\0';
if (c <= 0)
{ Token(';');
}
} while (c == ' '); /* '\t' is removed in tl_main.c */
if (islower(c))
{ getword(c, isalnum_);
if (strcmp("true", yytext) == 0)
{ Token(TRUE);
}
if (strcmp("false", yytext) == 0)
{ Token(FALSE);
}
tl_yylval = tl_nn(PREDICATE,ZN,ZN);
tl_yylval->sym = tl_lookup(yytext);
return PREDICATE;
}
if (c == '<')
{ c = tl_Getchar();
if (c == '>')
{ Token(EVENTUALLY);
}
if (c != '-')
{ tl_UnGetchar();
tl_yyerror("expected '<>' or '<->'");
}
c = tl_Getchar();
if (c == '>')
{ Token(EQUIV);
}
tl_UnGetchar();
tl_yyerror("expected '<->'");
}
switch (c) {
case '/' : c = follow('\\', AND, '/'); break;
case '\\': c = follow('/', OR, '\\'); break;
case '&' : c = follow('&', AND, '&'); break;
case '|' : c = follow('|', OR, '|'); break;
case '[' : c = follow(']', ALWAYS, '['); break;
case '-' : c = follow('>', IMPLIES, '-'); break;
case '!' : c = NOT; break;
case 'U' : c = U_OPER; break;
case 'V' : c = V_OPER; break;
#ifdef NXT
case 'X' : c = NEXT; break;
#endif
default : break;
}
Token(c);
}
Symbol *
tl_lookup(char *s)
{ Symbol *sp;
int h = hash(s);
for (sp = symtab[h]; sp; sp = sp->next)
if (strcmp(sp->name, s) == 0)
return sp;
sp = (Symbol *) tl_emalloc(sizeof(Symbol));
sp->name = (char *) tl_emalloc(strlen(s) + 1);
strcpy(sp->name, s);
sp->next = symtab[h];
symtab[h] = sp;
return sp;
}
Symbol *
getsym(Symbol *s)
{ Symbol *n = (Symbol *) tl_emalloc(sizeof(Symbol));
n->name = s->name;
return n;
}