tgba2ta.cc 21.3 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
// Copyright (C) 2010, 2011 Laboratoire de Recherche et Developpement
// de l Epita (LRDE).
//
// This file is part of Spot, a model checking library.
//
// Spot 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.
//
// Spot 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 Spot; see the file COPYING.  If not, write to the Free
// Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
// 02111-1307, USA.

21
//#define TRACE
22
23
24
25
26
27
28
29

#include <iostream>
#ifdef TRACE
#define trace std::clog
#else
#define trace while (0) std::clog
#endif

30
31
32
33
34
35
36
37
38
39
40
41
#include "ltlast/atomic_prop.hh"
#include "ltlast/constant.hh"
#include "tgba/formula2bdd.hh"
#include "misc/bddop.hh"
#include <cassert>
#include "ltlvisit/tostring.hh"
#include <iostream>
#include "tgba/bddprint.hh"
#include "tgbaalgos/gtec/nsheap.hh"
#include <stack>
#include "tgba2ta.hh"
#include "taalgos/statessetbuilder.hh"
42
#include "ta/tgbtaexplicit.hh"
43
44
45
46
47
48

using namespace std;

namespace spot
{

49
50
  ta_explicit*
  build_ta(ta_explicit* ta, bdd atomic_propositions_set_,
51
52
53
54
55
      bool artificial_initial_state_mode,
      bool artificial_livelock_accepting_state_mode, bool degeneralized)
  {

    std::stack<state_ta_explicit*> todo;
56
    const tgba* tgba_ = ta->get_tgba();
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158

    // build Initial states set:
    state* tgba_init_state = tgba_->get_init_state();

    bdd tgba_condition = tgba_->support_conditions(tgba_init_state);

    bdd satone_tgba_condition;
    while ((satone_tgba_condition = bdd_satoneset(tgba_condition,
        atomic_propositions_set_, bddtrue)) != bddfalse)
      {
        tgba_condition -= satone_tgba_condition;
        state_ta_explicit* init_state;
        if (degeneralized)
          {
            init_state = new state_ta_explicit(tgba_init_state->clone(),
                satone_tgba_condition, true,
                ((tgba_sba_proxy*) tgba_)->state_is_accepting(tgba_init_state));
          }
        else
          {
            init_state = new state_ta_explicit(tgba_init_state->clone(),
                satone_tgba_condition, true, false);
          }

        state_ta_explicit* s = ta->add_state(init_state);
        assert(s == init_state);
        ta->add_to_initial_states_set(s);

        todo.push(init_state);
      }
    tgba_init_state->destroy();

    while (!todo.empty())
      {
        state_ta_explicit* source = todo.top();
        todo.pop();

        tgba_succ_iterator* tgba_succ_it = tgba_->succ_iter(
            source->get_tgba_state());
        for (tgba_succ_it->first(); !tgba_succ_it->done(); tgba_succ_it->next())
          {
            const state* tgba_state = tgba_succ_it->current_state();
            bdd tgba_condition = tgba_succ_it->current_condition();
            bdd tgba_acceptance_conditions =
                tgba_succ_it->current_acceptance_conditions();
            bdd satone_tgba_condition;
            while ((satone_tgba_condition = bdd_satoneset(tgba_condition,
                atomic_propositions_set_, bddtrue)) != bddfalse)
              {

                tgba_condition -= satone_tgba_condition;

                bdd all_props = bddtrue;
                bdd dest_condition;
                if (satone_tgba_condition == source->get_tgba_condition())
                  while ((dest_condition = bdd_satoneset(all_props,
                      atomic_propositions_set_, bddtrue)) != bddfalse)
                    {
                      all_props -= dest_condition;
                      state_ta_explicit* new_dest;
                      if (degeneralized)
                        {

                          new_dest = new state_ta_explicit(tgba_state->clone(),
                              dest_condition, false,
                              ((tgba_sba_proxy*) tgba_)->state_is_accepting(
                                  tgba_state));

                        }
                      else
                        {
                          new_dest = new state_ta_explicit(tgba_state->clone(),
                              dest_condition, false, false);

                        }
                      state_ta_explicit* dest = ta->add_state(new_dest);

                      if (dest != new_dest)
                        {
                          // the state dest already exists in the testing automata
                          new_dest->get_tgba_state()->destroy();
                          delete new_dest;
                        }
                      else
                        {
                          todo.push(dest);
                        }

                      ta->create_transition(source, bdd_setxor(
                          source->get_tgba_condition(),
                          dest->get_tgba_condition()),
                          tgba_acceptance_conditions, dest);

                    }

              }
            tgba_state->destroy();
          }
        delete tgba_succ_it;

      }

159
160

    state_ta_explicit* artificial_livelock_accepting_state  = 0;
161
162
163
    if (artificial_livelock_accepting_state_mode)
      {
        state_ta_explicit* artificial_livelock_accepting_state =
164
165
            new state_ta_explicit(ta->get_tgba()->get_init_state(), bddtrue,
                false, false, true, 0);
166
      }
167
168


169
    compute_livelock_acceptance_states(ta,artificial_livelock_accepting_state);
170
171
172
173
174

    return ta;

  }

175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
  ta_explicit*
  tgba_to_ta(const tgba* tgba_, bdd atomic_propositions_set_,
      bool artificial_initial_state_mode,
      bool artificial_livelock_accepting_state_mode, bool degeneralized)
  {
    ta_explicit* ta;

    state* tgba_init_state = tgba_->get_init_state();
    if (artificial_initial_state_mode)
      {
        state_ta_explicit* ta_init_state = new state_ta_explicit(
            tgba_init_state->clone(), bddfalse, true);

        ta = new spot::ta_explicit(tgba_, tgba_->all_acceptance_conditions(),
            ta_init_state);
      }
    else
      {
        ta = new spot::ta_explicit(tgba_, tgba_->all_acceptance_conditions());
      }
    tgba_init_state->destroy();

    // build ta automata:
    build_ta(ta, atomic_propositions_set_, artificial_initial_state_mode,
        artificial_livelock_accepting_state_mode, degeneralized);
    return ta;
  }

203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
  void
  add_artificial_livelock_accepting_state(ta_explicit* testing_automata,
      state_ta_explicit* artificial_livelock_accepting_state)
  {

    state_ta_explicit* artificial_livelock_accepting_state_added =
        testing_automata->add_state(artificial_livelock_accepting_state);

    // unique artificial_livelock_accepting_state
    assert(artificial_livelock_accepting_state_added
        == artificial_livelock_accepting_state);

    ta::states_set_t states_set = testing_automata->get_states_set();
    ta::states_set_t::iterator it;

    std::set<bdd, bdd_less_than>* conditions_to_livelock_accepting_states =
        new std::set<bdd, bdd_less_than>;

    for (it = states_set.begin(); it != states_set.end(); it++)
      {

        state_ta_explicit* source = static_cast<state_ta_explicit*> (*it);

        conditions_to_livelock_accepting_states->clear();

        state_ta_explicit::transitions* trans = source->get_transitions();
        state_ta_explicit::transitions::iterator it_trans;

        if (trans != 0)
          for (it_trans = trans->begin(); it_trans != trans->end();)
            {
              state_ta_explicit* dest = (*it_trans)->dest;

236
237
238
239
240
              state_ta_explicit::transitions* dest_trans =
                  (dest)->get_transitions();
              bool dest_trans_empty = dest_trans == 0 || dest_trans->empty();

              //TODO TA++
241
              if (dest->is_livelock_accepting_state()
242
                  && (!dest->is_accepting_state() || dest_trans_empty))
243
244
245
246
247
248
249
                {
                  conditions_to_livelock_accepting_states->insert(
                      (*it_trans)->condition);

                }

              //remove hole successors states
250

251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
              if (dest_trans_empty)
                {
                  source->get_transitions((*it_trans)->condition)->remove(
                      *it_trans);
                  delete (*it_trans);
                  it_trans = trans->erase(it_trans);
                }
              else
                {
                  it_trans++;
                }
            }

        if (conditions_to_livelock_accepting_states != 0)
          {
            std::set<bdd, bdd_less_than>::iterator it_conditions;
            for (it_conditions
                = conditions_to_livelock_accepting_states->begin(); it_conditions
                != conditions_to_livelock_accepting_states->end(); it_conditions++)
              {

                testing_automata->create_transition(source, (*it_conditions),
273
                    bddfalse, artificial_livelock_accepting_state, true);
274
275
276
277
278
279
280

              }
          }

      }
    delete conditions_to_livelock_accepting_states;

281
282
283
284
285
286
287
288
289
290
291
292
293
    for (it = states_set.begin(); it != states_set.end(); it++)
      {

        state_ta_explicit* state = static_cast<state_ta_explicit*> (*it);
        state_ta_explicit::transitions* state_trans =
            (state)->get_transitions();
        bool state_trans_empty = state_trans == 0 || state_trans->empty();

        if (state->is_livelock_accepting_state()
            && (!state->is_accepting_state()) && (!state_trans_empty))
          state->set_livelock_accepting_state(false);
      }

294
295
296
297
298
299
300
301
  }

  namespace
  {
    typedef std::pair<spot::state*, tgba_succ_iterator*> pair_state_iter;
  }

  void
302
  compute_livelock_acceptance_states(ta_explicit* testing_automata, state_ta_explicit* artificial_livelock_accepting_state)
303
304
305
306
307
308
  {
    // We use five main data in this algorithm:
    // * sscc: a stack of strongly stuttering-connected components (SSCC)
    scc_stack_ta sscc;

    // * arc, a stack of acceptance conditions between each of these SCC,
309
    std::stack<bdd> arc;
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341

    // * h: a hash of all visited nodes, with their order,
    //   (it is called "Hash" in Couvreur's paper)
    numbered_state_heap* h =
        numbered_state_heap_hash_map_factory::instance()->build(); ///< Heap of visited states.

    // * num: the number of visited nodes.  Used to set the order of each
    //   visited node,
    int num = 0;

    // * todo: the depth-first search stack.  This holds pairs of the
    //   form (STATE, ITERATOR) where ITERATOR is a tgba_succ_iterator
    //   over the successors of STATE.  In our use, ITERATOR should
    //   always be freed when TODO is popped, but STATE should not because
    //   it is also used as a key in H.
    std::stack<pair_state_iter> todo;

    // * init: the set of the depth-first search initial states
    std::stack<state*> init_set;

    ta::states_set_t::const_iterator it;
    ta::states_set_t init_states = testing_automata->get_initial_states_set();
    for (it = init_states.begin(); it != init_states.end(); it++)
      {
        state* init_state = (*it);
        init_set.push(init_state);

      }

    while (!init_set.empty())
      {
        // Setup depth-first search from initial states.
342

343
344
345
346
          {
            state_ta_explicit* init =
                down_cast<state_ta_explicit*> (init_set.top());
            init_set.pop();
347
            state_ta_explicit* init_clone = init;
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
            numbered_state_heap::state_index_p h_init = h->find(init_clone);

            if (h_init.first)
              continue;

            h->insert(init_clone, ++num);
            sscc.push(num);
            arc.push(bddfalse);
            sscc.top().is_accepting
                = testing_automata->is_accepting_state(init);
            tgba_succ_iterator* iter = testing_automata->succ_iter(init);
            iter->first();
            todo.push(pair_state_iter(init, iter));

          }

        while (!todo.empty())
          {

            state* curr = todo.top().first;

369
            numbered_state_heap::state_index_p spi = h->find(curr);
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
            // If we have reached a dead component, ignore it.
            if (*spi.second == -1)
              {
                todo.pop();
                continue;
              }

            // We are looking at the next successor in SUCC.
            tgba_succ_iterator* succ = todo.top().second;

            // If there is no more successor, backtrack.
            if (succ->done())
              {
                // We have explored all successors of state CURR.

                // Backtrack TODO.
                todo.pop();

                // fill rem with any component removed,
389
                numbered_state_heap::state_index_p spi = h->index(curr);
390
391
392
393
394
395
396
397
398
399
400
401
                assert(spi.first);

                sscc.rem().push_front(curr);

                // When backtracking the root of an SSCC, we must also
                // remove that SSCC from the ROOT stacks.  We must
                // discard from H all reachable states from this SSCC.
                assert(!sscc.empty());
                if (sscc.top().index == *spi.second)
                  {
                    // removing states
                    std::list<state*>::iterator i;
402
403
404
                    bool is_livelock_accepting_sscc = (sscc.rem().size() > 1)
                        && ((sscc.top().is_accepting) || (sscc.top().condition
                            == testing_automata->all_acceptance_conditions()));
405
406
407

                    for (i = sscc.rem().begin(); i != sscc.rem().end(); ++i)
                      {
408
                        numbered_state_heap::state_index_p spi = h->index((*i));
409
410
411
412
413
414
415
416
417
418
419
420
                        assert(spi.first->compare(*i) == 0);
                        assert(*spi.second != -1);
                        *spi.second = -1;
                        if (is_livelock_accepting_sscc)
                          {//if it is an accepting sscc
                            //add the state to G (=the livelock-accepting states set)

                            state_ta_explicit * livelock_accepting_state =
                                down_cast<state_ta_explicit*> (*i);

                            livelock_accepting_state->set_livelock_accepting_state(
                                true);
421
                            if (artificial_livelock_accepting_state != 0) livelock_accepting_state->set_accepting_state(true);
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
                          }

                      }

                    assert(!arc.empty());
                    sscc.pop();
                    arc.pop();

                  }

                // automata reduction
                testing_automata->delete_stuttering_and_hole_successors(curr);

                delete succ;
                // Do not delete CURR: it is a key in H.
                continue;
              }

            // Fetch the values destination state we are interested in...
            state* dest = succ->current_state();

            bdd acc_cond = succ->current_acceptance_conditions();
            // ... and point the iterator to the next successor, for
            // the next iteration.
            succ->next();
            // We do not need SUCC from now on.


            // Are we going to a new state through a stuttering transition?
            bool is_stuttering_transition =
                testing_automata->get_state_condition(curr)
                    == testing_automata->get_state_condition(dest);
454
            state* dest_clone = dest;
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
            spi = h->find(dest_clone);

            // Is this a new state?
            if (!spi.first)
              {
                if (!is_stuttering_transition)
                  {
                    init_set.push(dest);
                    dest_clone->destroy();
                    continue;
                  }

                // Number it, stack it, and register its successors
                // for later processing.
                h->insert(dest_clone, ++num);
                sscc.push(num);
                arc.push(acc_cond);
                sscc.top().is_accepting = testing_automata->is_accepting_state(
                    dest);

                tgba_succ_iterator* iter = testing_automata->succ_iter(dest);
                iter->first();
                todo.push(pair_state_iter(dest, iter));
                continue;
              }

            // If we have reached a dead component, ignore it.
            if (*spi.second == -1)
              continue;

485
486
            trace
              << "***compute_livelock_acceptance_states: CYCLE***" << std::endl;
487

488
489
490
491
492
493
            if (!curr->compare(dest))
              {
                state_ta_explicit * self_loop_state =
                    down_cast<state_ta_explicit*> (curr);
                assert(self_loop_state);

494
495
496
                if (testing_automata->is_accepting_state(self_loop_state)
                    || (acc_cond
                        == testing_automata->all_acceptance_conditions()))
497
498
499
500
501
502
                  {
                    self_loop_state->set_livelock_accepting_state(true);
                    self_loop_state->set_accepting_state(true);

                  }

503
                trace
504
505
                      << "***compute_livelock_acceptance_states: CYCLE: self_loop_state***"
                      << std::endl;
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551

              }

            // Now this is the most interesting case.  We have reached a
            // state S1 which is already part of a non-dead SSCC.  Any such
            // non-dead SSCC has necessarily been crossed by our path to
            // this state: there is a state S2 in our path which belongs
            // to this SSCC too.  We are going to merge all states between
            // this S1 and S2 into this SSCC.
            //
            // This merge is easy to do because the order of the SSCC in
            // ROOT is ascending: we just have to merge all SSCCs from the
            // top of ROOT that have an index greater to the one of
            // the SSCC of S2 (called the "threshold").
            int threshold = *spi.second;
            std::list<state*> rem;
            bool acc = false;

            while (threshold < sscc.top().index)
              {
                assert(!sscc.empty());
                assert(!arc.empty());
                acc |= sscc.top().is_accepting;
                acc_cond |= sscc.top().condition;
                acc_cond |= arc.top();
                rem.splice(rem.end(), sscc.rem());
                sscc.pop();
                arc.pop();
              }

            // Note that we do not always have
            //  threshold == sscc.top().index
            // after this loop, the SSCC whose index is threshold might have
            // been merged with a lower SSCC.

            // Accumulate all acceptance conditions into the merged SSCC.
            sscc.top().is_accepting |= acc;
            sscc.top().condition |= acc_cond;

            sscc.rem().splice(sscc.rem().end(), rem);

          }

      }
    delete h;

552
    if (artificial_livelock_accepting_state != 0) add_artificial_livelock_accepting_state(testing_automata, artificial_livelock_accepting_state);
553
  }
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569

  tgbta_explicit*
  tgba_to_tgbta(const tgba* tgba_, bdd atomic_propositions_set_)
  {

    state* tgba_init_state = tgba_->get_init_state();
    state_ta_explicit* ta_init_state = new state_ta_explicit(
        tgba_init_state->clone(), bddfalse, true);
    tgba_init_state->destroy();

    tgbta_explicit* tgbta = new spot::tgbta_explicit(tgba_,
        tgba_->all_acceptance_conditions(), ta_init_state);

    // build ta automata:
    build_ta(tgbta, atomic_propositions_set_, true, true, false);

570
571
    trace
      << "***tgba_to_tgbta: POST build_ta***" << std::endl;
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596

    // adapt a ta automata to build tgbta automata :
    ta::states_set_t states_set = tgbta->get_states_set();
    ta::states_set_t::iterator it;
    tgba_succ_iterator* initial_states_iter = tgbta->succ_iter(
        tgbta->get_artificial_initial_state());
    initial_states_iter->first();
    if (initial_states_iter->done())
      return tgbta;
    bdd first_state_condition = (initial_states_iter)->current_condition();
    delete initial_states_iter;

    bdd bdd_stutering_transition = bdd_setxor(first_state_condition,
        first_state_condition);

    for (it = states_set.begin(); it != states_set.end(); it++)
      {

        state_ta_explicit* state = static_cast<state_ta_explicit*> (*it);

        state_ta_explicit::transitions* trans = state->get_transitions();
        if (state->is_livelock_accepting_state())
          {

            bool trans_empty = (trans == 0 || trans->empty());
597
            if (trans_empty || state->is_accepting_state())
598
599
              {
                trace
600
601
                      << "***tgba_to_tgbta: PRE if (state->is_livelock_accepting_state()) ... create_transition ***"
                      << std::endl;
602
603
604
                tgbta->create_transition(state, bdd_stutering_transition,
                    tgbta->all_acceptance_conditions(), state);
                trace
605
606
                      << "***tgba_to_tgbta: POST if (state->is_livelock_accepting_state()) ... create_transition ***"
                      << std::endl;
607
608

              }
609

610
611
612
613
614
615
          }

        if (state->compare(tgbta->get_artificial_initial_state()))
          tgbta->create_transition(state, bdd_stutering_transition, bddfalse,
              state);

616
617
618
619
        state->set_livelock_accepting_state(false);
        state->set_accepting_state(false);
        trace
          << "***tgba_to_tgbta: POST create_transition ***" << std::endl;
620
621
622
623
624
625
626

      }

    return tgbta;

  }

627
}