ltl2ba-nix/alternating.c

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/***** ltl2ba : alternating.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 */
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#include "config.h"
#include "ltl2ba.h"
#include "util.h"
#include <sys/resource.h>
/********************************************************************\
|* Structures and shared variables *|
\********************************************************************/
extern FILE *tl_out;
extern int tl_verbose, tl_stats, tl_simp_diff;
Node **label;
char **sym_table;
ATrans **transition;
struct rusage tr_debut, tr_fin;
struct timeval t_diff;
int *final_set, node_id = 1, sym_id = 0, node_size, sym_size, n_sym;
int astate_count = 0, atrans_count = 0;
ATrans *build_alternating(Node *p);
/********************************************************************\
|* Generation of the alternating automaton *|
\********************************************************************/
int calculate_node_size(Node *p) /* returns the number of temporal nodes */
{
switch(p->ntyp) {
case AND:
case OR:
case U_OPER:
case V_OPER:
return(calculate_node_size(p->lft) + calculate_node_size(p->rgt) + 1);
#ifdef NXT
case NEXT:
return(calculate_node_size(p->lft) + 1);
#endif
default:
return 1;
break;
}
}
int calculate_sym_size(Node *p) /* returns the number of predicates */
{
switch(p->ntyp) {
case AND:
case OR:
case U_OPER:
case V_OPER:
return(calculate_sym_size(p->lft) + calculate_sym_size(p->rgt));
#ifdef NXT
case NEXT:
return(calculate_sym_size(p->lft));
#endif
case NOT:
case PREDICATE:
return 1;
default:
return 0;
}
}
ATrans *dup_trans(ATrans *trans) /* returns the copy of a transition */
{
ATrans *result;
if(!trans) return trans;
result = emalloc_atrans();
copy_set(trans->to, result->to, 0);
copy_set(trans->pos, result->pos, 1);
copy_set(trans->neg, result->neg, 1);
return result;
}
void do_merge_trans(ATrans **result, ATrans *trans1, ATrans *trans2)
{ /* merges two transitions */
if(!trans1 || !trans2) {
free_atrans(*result, 0);
*result = (ATrans *)0;
return;
}
if(!*result)
*result = emalloc_atrans();
do_merge_sets((*result)->to, trans1->to, trans2->to, 0);
do_merge_sets((*result)->pos, trans1->pos, trans2->pos, 1);
do_merge_sets((*result)->neg, trans1->neg, trans2->neg, 1);
if(!empty_intersect_sets((*result)->pos, (*result)->neg, 1)) {
free_atrans(*result, 0);
*result = (ATrans *)0;
}
}
ATrans *merge_trans(ATrans *trans1, ATrans *trans2) /* merges two transitions */
{
ATrans *result = emalloc_atrans();
do_merge_trans(&result, trans1, trans2);
return result;
}
int already_done(Node *p) /* finds the id of the node, if already explored */
{
int i;
for(i = 1; i<node_id; i++)
if (isequal(p, label[i]))
return i;
return -1;
}
int get_sym_id(char *s) /* finds the id of a predicate, or attributes one */
{
int i;
for(i=0; i<sym_id; i++)
if (!strcmp(s, sym_table[i]))
return i;
sym_table[sym_id] = s;
return sym_id++;
}
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ATrans *_boolean(Node *p) /* computes the transitions to boolean nodes -> next & init */
{
ATrans *t1, *t2, *lft, *rgt, *result = (ATrans *)0;
switch(p->ntyp) {
case TRUE:
result = emalloc_atrans();
clear_set(result->to, 0);
clear_set(result->pos, 1);
clear_set(result->neg, 1);
case FALSE:
break;
case AND:
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lft = _boolean(p->lft);
rgt = _boolean(p->rgt);
for(t1 = lft; t1; t1 = t1->nxt) {
for(t2 = rgt; t2; t2 = t2->nxt) {
ATrans *tmp = merge_trans(t1, t2);
if(tmp) {
tmp->nxt = result;
result = tmp;
}
}
}
free_atrans(lft, 1);
free_atrans(rgt, 1);
break;
case OR:
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lft = _boolean(p->lft);
for(t1 = lft; t1; t1 = t1->nxt) {
ATrans *tmp = dup_trans(t1);
tmp->nxt = result;
result = tmp;
}
free_atrans(lft, 1);
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rgt = _boolean(p->rgt);
for(t1 = rgt; t1; t1 = t1->nxt) {
ATrans *tmp = dup_trans(t1);
tmp->nxt = result;
result = tmp;
}
free_atrans(rgt, 1);
break;
default:
build_alternating(p);
result = emalloc_atrans();
clear_set(result->to, 0);
clear_set(result->pos, 1);
clear_set(result->neg, 1);
add_set(result->to, already_done(p));
}
return result;
}
ATrans *build_alternating(Node *p) /* builds an alternating automaton for p */
{
ATrans *t1, *t2, *t = (ATrans *)0;
int node = already_done(p);
if(node >= 0) return transition[node];
switch (p->ntyp) {
case TRUE:
t = emalloc_atrans();
clear_set(t->to, 0);
clear_set(t->pos, 1);
clear_set(t->neg, 1);
case FALSE:
break;
case PREDICATE:
t = emalloc_atrans();
clear_set(t->to, 0);
clear_set(t->pos, 1);
clear_set(t->neg, 1);
add_set(t->pos, get_sym_id(p->sym->name));
break;
case NOT:
t = emalloc_atrans();
clear_set(t->to, 0);
clear_set(t->pos, 1);
clear_set(t->neg, 1);
add_set(t->neg, get_sym_id(p->lft->sym->name));
break;
#ifdef NXT
case NEXT:
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t = _boolean(p->lft);
break;
#endif
case U_OPER: /* p U q <-> q || (p && X (p U q)) */
for(t2 = build_alternating(p->rgt); t2; t2 = t2->nxt) {
ATrans *tmp = dup_trans(t2); /* q */
tmp->nxt = t;
t = tmp;
}
for(t1 = build_alternating(p->lft); t1; t1 = t1->nxt) {
ATrans *tmp = dup_trans(t1); /* p */
add_set(tmp->to, node_id); /* X (p U q) */
tmp->nxt = t;
t = tmp;
}
add_set(final_set, node_id);
break;
case V_OPER: /* p V q <-> (p && q) || (p && X (p V q)) */
for(t1 = build_alternating(p->rgt); t1; t1 = t1->nxt) {
ATrans *tmp;
for(t2 = build_alternating(p->lft); t2; t2 = t2->nxt) {
tmp = merge_trans(t1, t2); /* p && q */
if(tmp) {
tmp->nxt = t;
t = tmp;
}
}
tmp = dup_trans(t1); /* p */
add_set(tmp->to, node_id); /* X (p V q) */
tmp->nxt = t;
t = tmp;
}
break;
case AND:
t = (ATrans *)0;
for(t1 = build_alternating(p->lft); t1; t1 = t1->nxt) {
for(t2 = build_alternating(p->rgt); t2; t2 = t2->nxt) {
ATrans *tmp = merge_trans(t1, t2);
if(tmp) {
tmp->nxt = t;
t = tmp;
}
}
}
break;
case OR:
t = (ATrans *)0;
for(t1 = build_alternating(p->lft); t1; t1 = t1->nxt) {
ATrans *tmp = dup_trans(t1);
tmp->nxt = t;
t = tmp;
}
for(t1 = build_alternating(p->rgt); t1; t1 = t1->nxt) {
ATrans *tmp = dup_trans(t1);
tmp->nxt = t;
t = tmp;
}
break;
default:
break;
}
transition[node_id] = t;
label[node_id++] = p;
return(t);
}
/********************************************************************\
|* Simplification of the alternating automaton *|
\********************************************************************/
void simplify_atrans(ATrans **trans) /* simplifies the transitions */
{
ATrans *t, *father = (ATrans *)0;
for(t = *trans; t;) {
ATrans *t1;
for(t1 = *trans; t1; t1 = t1->nxt) {
if((t1 != t) &&
included_set(t1->to, t->to, 0) &&
included_set(t1->pos, t->pos, 1) &&
included_set(t1->neg, t->neg, 1))
break;
}
if(t1) {
if (father)
father->nxt = t->nxt;
else
*trans = t->nxt;
free_atrans(t, 0);
if (father)
t = father->nxt;
else
t = *trans;
continue;
}
atrans_count++;
father = t;
t = t->nxt;
}
}
void simplify_astates() /* simplifies the alternating automaton */
{
ATrans *t;
int i, *acc = make_set(-1, 0); /* no state is accessible initially */
for(t = transition[0]; t; t = t->nxt, i = 0)
merge_sets(acc, t->to, 0); /* all initial states are accessible */
for(i = node_id - 1; i > 0; i--) {
if (!in_set(acc, i)) { /* frees unaccessible states */
label[i] = ZN;
free_atrans(transition[i], 1);
transition[i] = (ATrans *)0;
continue;
}
astate_count++;
simplify_atrans(&transition[i]);
for(t = transition[i]; t; t = t->nxt)
merge_sets(acc, t->to, 0);
}
tfree(acc);
}
/********************************************************************\
|* Display of the alternating automaton *|
\********************************************************************/
void print_alternating() /* dumps the alternating automaton */
{
int i;
ATrans *t;
fprintf(tl_out, "init :\n");
for(t = transition[0]; t; t = t->nxt) {
print_set(t->to, 0);
fprintf(tl_out, "\n");
}
for(i = node_id - 1; i > 0; i--) {
if(!label[i])
continue;
fprintf(tl_out, "state %i : ", i);
dump(label[i]);
fprintf(tl_out, "\n");
for(t = transition[i]; t; t = t->nxt) {
if (empty_set(t->pos, 1) && empty_set(t->neg, 1))
fprintf(tl_out, "1");
print_set(t->pos, 1);
if (!empty_set(t->pos,1) && !empty_set(t->neg,1)) fprintf(tl_out, " & ");
print_set(t->neg, 2);
fprintf(tl_out, " -> ");
print_set(t->to, 0);
fprintf(tl_out, "\n");
}
}
}
/********************************************************************\
|* Main method *|
\********************************************************************/
void mk_alternating(Node *p) /* generates an alternating automaton for p */
{
if(tl_stats) getrusage(RUSAGE_SELF, &tr_debut);
node_size = calculate_node_size(p) + 1; /* number of states in the automaton */
label = (Node **) tl_emalloc(node_size * sizeof(Node *));
transition = (ATrans **) tl_emalloc(node_size * sizeof(ATrans *));
node_size = node_size / (8 * sizeof(int)) + 1;
n_sym = calculate_sym_size(p); /* number of predicates */
if(n_sym) sym_table = (char **) tl_emalloc(n_sym * sizeof(char *));
sym_size = n_sym / (8 * sizeof(int)) + 1;
final_set = make_set(-1, 0);
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transition[0] = _boolean(p); /* generates the alternating automaton */
if(tl_verbose) {
fprintf(tl_out, "\nAlternating automaton before simplification\n");
print_alternating();
}
if(tl_simp_diff) {
simplify_astates(); /* keeps only accessible states */
if(tl_verbose) {
fprintf(tl_out, "\nAlternating automaton after simplification\n");
print_alternating();
}
}
if(tl_stats) {
getrusage(RUSAGE_SELF, &tr_fin);
timeval_subtract (&t_diff, &tr_fin.ru_utime, &tr_debut.ru_utime);
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fprintf(tl_out, "\nBuilding and simplification of the alternating automaton: %lli.%06ld",
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(long long int)t_diff.tv_sec, t_diff.tv_usec);
fprintf(tl_out, "\n%i states, %i transitions\n", astate_count, atrans_count);
}
releasenode(1, p);
tfree(label);
}