twa.hh 44.6 KB
Newer Older
1
// -*- coding: utf-8 -*-
2 3
// Copyright (C) 2009, 2011, 2013, 2014, 2015, 2016 Laboratoire de
// Recherche et Développement de l'Epita (LRDE).
Guillaume Sadegh's avatar
Guillaume Sadegh committed
4
// Copyright (C) 2003, 2004, 2005 Laboratoire d'Informatique de
5 6
// Paris 6 (LIP6), département Systèmes Répartis Coopératifs (SRC),
// Université Pierre et Marie Curie.
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
7 8 9 10 11
//
// 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
12
// the Free Software Foundation; either version 3 of the License, or
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
13 14 15 16 17 18 19 20
// (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
21
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
22

23
#pragma once
24

25
#include <cstddef>
26 27 28
#include <spot/twa/fwd.hh>
#include <spot/twa/acc.hh>
#include <spot/twa/bdddict.hh>
29 30
#include <cassert>
#include <memory>
31 32
#include <unordered_map>
#include <functional>
33
#include <array>
34
#include <vector>
35 36 37
#include <spot/misc/casts.hh>
#include <spot/misc/hash.hh>
#include <spot/tl/formula.hh>
38
#include <spot/misc/trival.hh>
39 40 41

namespace spot
{
42 43 44 45 46 47
  struct twa_run;
  typedef std::shared_ptr<twa_run> twa_run_ptr;

  struct twa_word;
  typedef std::shared_ptr<twa_word> twa_word_ptr;

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
48
  /// \ingroup twa_essentials
49 50 51 52 53 54 55 56 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
  /// \brief Abstract class for states.
  class SPOT_API state
  {
  public:
    /// \brief Compares two states (that come from the same automaton).
    ///
    /// This method returns an integer less than, equal to, or greater
    /// than zero if \a this is found, respectively, to be less than, equal
    /// to, or greater than \a other according to some implicit total order.
    ///
    /// This method should not be called to compare states from
    /// different automata.
    ///
    /// \sa spot::state_ptr_less_than
    virtual int compare(const state* other) const = 0;

    /// \brief Hash a state.
    ///
    /// This method returns an integer that can be used as a
    /// hash value for this state.
    ///
    /// Note that the hash value is guaranteed to be unique for all
    /// equal states (in compare()'s sense) for only has long has one
    /// of these states exists.  So it's OK to use a spot::state as a
    /// key in a \c hash_map because the mere use of the state as a
    /// key in the hash will ensure the state continues to exist.
    ///
    /// However if you create the state, get its hash key, delete the
    /// state, recreate the same state, and get its hash key, you may
    /// obtain two different hash keys if the same state were not
    /// already used elsewhere.  In practice this weird situation can
    /// occur only when the state is BDD-encoded, because BDD numbers
    /// (used to build the hash value) can be reused for other
    /// formulas.  That probably doesn't matter, since the hash value
    /// is meant to be used in a \c hash_map, but it had to be noted.
    virtual size_t hash() const = 0;

    /// Duplicate a state.
    virtual state* clone() const = 0;

    /// \brief Release a state.
    ///
91
    /// Methods from the tgba or twa_succ_iterator always return a
92 93 94 95 96 97 98 99 100 101 102 103 104 105 106
    /// new state that you should deallocate with this function.
    /// Before Spot 0.7, you had to "delete" your state directly.
    /// Starting with Spot 0.7, you should update your code to use
    /// this function instead. destroy() usually call delete, except
    /// in subclasses that destroy() to allow better memory management
    /// (e.g., no memory allocation for explicit automata).
    virtual void destroy() const
    {
      delete this;
    }

  protected:
    /// \brief Destructor.
    ///
    /// Note that client code should call
107 108 109
    /// \code s->destroy(); \endcode
    /// instead of
    /// \code delete s; \endcode .
110 111 112 113 114
    virtual ~state()
    {
    }
  };

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
115
  /// \ingroup twa_essentials
116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131
  /// \brief Strict Weak Ordering for \c state*.
  ///
  /// This is meant to be used as a comparison functor for
  /// STL \c map whose key are of type \c state*.
  ///
  /// For instance here is how one could declare
  /// a map of \c state*.
  /// \code
  ///   // Remember how many times each state has been visited.
  ///   std::map<spot::state*, int, spot::state_ptr_less_than> seen;
  /// \endcode
  struct state_ptr_less_than
  {
    bool
    operator()(const state* left, const state* right) const
    {
132
      SPOT_ASSERT(left);
133 134 135 136
      return left->compare(right) < 0;
    }
  };

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
137
  /// \ingroup twa_essentials
138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154
  /// \brief An Equivalence Relation for \c state*.
  ///
  /// This is meant to be used as a comparison functor for
  /// an \c unordered_map whose key are of type \c state*.
  ///
  /// For instance here is how one could declare
  /// a map of \c state*.
  /// \code
  ///   // Remember how many times each state has been visited.
  ///   std::unordered_map<spot::state*, int, spot::state_ptr_hash,
  ///                                    spot::state_ptr_equal> seen;
  /// \endcode
  struct state_ptr_equal
  {
    bool
    operator()(const state* left, const state* right) const
    {
155
      SPOT_ASSERT(left);
156 157 158 159
      return 0 == left->compare(right);
    }
  };

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
160
  /// \ingroup twa_essentials
161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178
  /// \ingroup hash_funcs
  /// \brief Hash Function for \c state*.
  ///
  /// This is meant to be used as a hash functor for
  /// an \c unordered_map whose key are of type \c state*.
  ///
  /// For instance here is how one could declare
  /// a map of \c state*.
  /// \code
  ///   // Remember how many times each state has been visited.
  ///   std::unordered_map<spot::state*, int, spot::state_ptr_hash,
  ///                                    spot::state_ptr_equal> seen;
  /// \endcode
  struct state_ptr_hash
  {
    size_t
    operator()(const state* that) const
    {
179
      SPOT_ASSERT(that);
180 181 182 183
      return that->hash();
    }
  };

184 185 186 187 188
  /// \brief Unordered set of abstract states
  ///
  /// Destroying each state if needed is the user's responsibility.
  ///
  /// \see state_unicity_table
189
  typedef std::unordered_set<const state*,
190
                             state_ptr_hash, state_ptr_equal> state_set;
191

192 193 194 195 196
  /// \brief Unordered map of abstract states
  ///
  /// Destroying each state if needed is the user's responsibility.
  template<class val>
  using state_map = std::unordered_map<const state*, val,
197
                                       state_ptr_hash, state_ptr_equal>;
198

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
199
  /// \ingroup twa_essentials
200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217
  /// \brief Render state pointers unique via a hash table.
  class SPOT_API state_unicity_table
  {
    state_set m;
  public:

    /// \brief Canonicalize state pointer.
    ///
    /// If this is the first time a state is seen, this return the
    /// state pointer as-is, otherwise it frees the state and returns
    /// a point to the previously seen copy.
    ///
    /// States are owned by the table and will be freed on
    /// destruction.
    const state* operator()(const state* s)
    {
      auto p = m.insert(s);
      if (!p.second)
218
        s->destroy();
219 220 221 222 223 224 225 226 227 228 229
      return *p.first;
    }

    /// \brief Canonicalize state pointer.
    ///
    /// Same as operator(), except that a nullptr
    /// is returned if the state is not new.
    const state* is_new(const state* s)
    {
      auto p = m.insert(s);
      if (!p.second)
230 231 232 233
        {
          s->destroy();
          return nullptr;
        }
234 235 236 237 238 239
      return *p.first;
    }

    ~state_unicity_table()
    {
      for (state_set::iterator i = m.begin(); i != m.end();)
240 241 242 243 244 245
        {
          // Advance the iterator before destroying its key.  This
          // avoid issues with old g++ implementations.
          state_set::iterator old = i++;
          (*old)->destroy();
        }
246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263
    }

    size_t
    size()
    {
      return m.size();
    }
  };



  // Functions related to shared_ptr.
  //////////////////////////////////////////////////

  typedef std::shared_ptr<const state> shared_state;

  inline void shared_state_deleter(state* s) { s->destroy(); }

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
264
  /// \ingroup twa_essentials
265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282
  /// \brief Strict Weak Ordering for \c shared_state
  /// (shared_ptr<const state*>).
  ///
  /// This is meant to be used as a comparison functor for
  /// STL \c map whose key are of type \c shared_state.
  ///
  /// For instance here is how one could declare
  /// a map of \c shared_state.
  /// \code
  ///   // Remember how many times each state has been visited.
  ///   std::map<shared_state, int, spot::state_shared_ptr_less_than> seen;
  /// \endcode
  struct state_shared_ptr_less_than
  {
    bool
    operator()(shared_state left,
               shared_state right) const
    {
283
      SPOT_ASSERT(left);
284 285 286 287
      return left->compare(right.get()) < 0;
    }
  };

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
288
  /// \ingroup twa_essentials
289 290 291 292
  /// \brief An Equivalence Relation for \c shared_state
  /// (shared_ptr<const state*>).
  ///
  /// This is meant to be used as a comparison functor for
293
  /// an \c unordered_map whose key are of type \c shared_state.
294 295 296 297 298 299 300 301 302
  ///
  /// For instance here is how one could declare
  /// a map of \c shared_state
  /// \code
  ///   // Remember how many times each state has been visited.
  ///   std::unordered_map<shared_state, int,
  ///                      state_shared_ptr_hash,
  ///                      state_shared_ptr_equal> seen;
  /// \endcode
303 304
  ///
  /// \see shared_state_set
305 306 307 308 309 310
  struct state_shared_ptr_equal
  {
    bool
    operator()(shared_state left,
               shared_state right) const
    {
311
      SPOT_ASSERT(left);
312 313 314 315
      return 0 == left->compare(right.get());
    }
  };

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
316
  /// \ingroup twa_essentials
317 318 319 320 321 322 323 324 325 326 327 328 329 330 331
  /// \ingroup hash_funcs
  /// \brief Hash Function for \c shared_state (shared_ptr<const state*>).
  ///
  /// This is meant to be used as a hash functor for
  /// an \c unordered_map whose key are of type
  /// \c shared_state.
  ///
  /// For instance here is how one could declare
  /// a map of \c shared_state.
  /// \code
  ///   // Remember how many times each state has been visited.
  ///   std::unordered_map<shared_state, int,
  ///                      state_shared_ptr_hash,
  ///                      state_shared_ptr_equal> seen;
  /// \endcode
332 333
  ///
  /// \see shared_state_set
334 335 336 337 338
  struct state_shared_ptr_hash
  {
    size_t
    operator()(shared_state that) const
    {
339
      SPOT_ASSERT(that);
340 341 342 343
      return that->hash();
    }
  };

344
  /// Unordered set of shared states
345
  typedef std::unordered_set<shared_state,
346 347
                             state_shared_ptr_hash,
                             state_shared_ptr_equal> shared_state_set;
348

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
349
  /// \ingroup twa_essentials
350 351
  /// \brief Iterate over the successors of a state.
  ///
352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396
  /// This class provides the basic functionality required to iterate
  /// over the set of edges leaving a given state.  Instance of
  /// twa_succ_iterator should normally not be created directly.
  /// Instead, they are created by passing a "source" state to
  /// twa::succ_iter(), which will create the instance of
  /// twa_succ_iterator to iterate over the successors of that state.
  ///
  /// This twa_succ_iterator class offers two types of services,
  /// offered by two groups of methods.  The methods first(), next(),
  /// and done() allow iteration over the set of outgoing edges.
  /// The methods cond(), acc(), dst(), allow inspecting the current
  /// edge.
  ///
  /// The twa_succ_iterator is usually subclassed so that iteration
  /// methods and accessor methods can be implemented differently in
  /// different automata.  In particular, this interface allows
  /// computing the set of successor on the fly if needed.
  ///
  /// The iterator can be used to iterate over all successors in a
  /// loop as follows:
  ///
  /// \code
  ///     for (i->first(); !i->done(); i->next())
  ///       {
  ///         // use i->cond(), i->acc(), i->dst()
  ///       }
  /// \endcode
  ///
  /// If there are n successors, there will be 1 call to first(), n
  /// calls to next() and n+1 calls to done(), so a total of 2(n+1)
  /// calls to virtual methods just to handle the iteration.  For this
  /// reason, we usually favor the following more efficient way of
  /// performing the same loop:
  ///
  /// \code
  ///     if (i->first())
  ///       do
  ///         {
  ///           // use i->cond(), i->acc(), i->dst()
  ///         }
  ///       while(i->next());
  /// \endcode
  ///
  /// This loops uses the return value of first() and next() to save
  /// n+1 calls to done().
397
  class SPOT_API twa_succ_iterator
398 399 400
  {
  public:
    virtual
401
    ~twa_succ_iterator()
402 403 404 405
    {
    }

    /// \name Iteration
406
    ///@{
407 408 409

    /// \brief Position the iterator on the first successor (if any).
    ///
410 411
    /// This method can be called several times in order to make
    /// multiple passes over successors.
412 413 414 415 416 417
    ///
    /// \warning One should always call \c done() (or better: check
    /// the return value of first()) to ensure there is a successor,
    /// even after \c first().  A common trap is to assume that there
    /// is at least one successor: this is wrong.
    ///
418 419 420 421
    /// \return true iff there is at least one successor
    ///
    /// If first() returns false, it is invalid to call next(),
    /// cond(), acc(), or dst().
422 423 424 425 426 427 428
    virtual bool first() = 0;

    /// \brief Jump to the next successor (if any).
    ///
    /// \warning Again, one should always call \c done() (or better:
    /// check the return value of next()) ensure there is a successor.
    ///
429 430 431 432 433
    /// \return true if the iterator moved to a new successor, false
    /// if the iterator could not move to a new successor.
    ///
    /// If next() returns false, it is invalid to call next() again,
    /// or to call cond(), acc() or dst().
434 435 436 437 438 439 440
    virtual bool next() = 0;

    /// \brief Check whether the iteration is finished.
    ///
    /// This function should be called after any call to \c first()
    /// or \c next() and before any enquiry about the current state.
    ///
441
    /// The typical use case of done() is in a \c for loop such as:
442 443 444
    ///
    ///     for (s->first(); !s->done(); s->next())
    ///       ...
445 446 447 448 449 450
    ///
    /// \return false iff the iterator is pointing to a successor.
    ///
    /// It is incorrect to call done() if first() hasn't been called
    /// before.  If done() returns true, it is invalid to call
    /// next(), cond(), acc(), or dst().
451 452
    virtual bool done() const = 0;

453
    ///@}
454 455

    /// \name Inspection
456
    ///@{
457

458
    /// \brief Get the destination state of the current edge.
459
    ///
460 461 462
    /// Each call to dst() (even several times on the same edge)
    /// creates a new state that has to be destroyed (see
    /// state::destroy()).  by the caller after it is no longer used.
463
    ///
464 465 466
    /// Note that the same state may occur at different points in the
    /// iteration, as different outgoing edges (usually with different
    /// labels or acceptance membership) may go to the same state.
467
    virtual const state* dst() const = 0;
468
    /// \brief Get the condition on the edge leading to this successor.
469 470
    ///
    /// This is a boolean function of atomic propositions.
471
    virtual bdd cond() const = 0;
472 473
    /// \brief Get the acceptance mark of the edge leading to this
    /// successor.
474
    virtual acc_cond::mark_t acc() const = 0;
475

476
    ///@}
477 478 479 480
  };

  namespace internal
  {
481
    /// \brief Helper structure to iterate over the successor of a
482
    /// state using the on-the-fly interface.
483 484 485
    ///
    /// This one emulates an STL-like iterator over the
    /// twa_succ_iterator interface.
486 487 488
    struct SPOT_API succ_iterator
    {
    protected:
489
      twa_succ_iterator* it_;
490 491
    public:

492
      succ_iterator(twa_succ_iterator* it):
493
        it_(it)
494 495 496 497 498
      {
      }

      bool operator==(succ_iterator o) const
      {
499
        return it_ == o.it_;
500 501 502 503
      }

      bool operator!=(succ_iterator o) const
      {
504
        return it_ != o.it_;
505 506
      }

507
      const twa_succ_iterator* operator*() const
508
      {
509
        return it_;
510 511 512 513
      }

      void operator++()
      {
514 515
        if (!it_->next())
          it_ = nullptr;
516 517
      }
    };
518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554

#ifndef SWIG
    /// \brief Helper class to iterate over the successor of a state
    /// using the on-the-fly interface
    ///
    /// This one emulates an STL-like container with begin()/end()
    /// methods so that it can be iterated using a ranged-for.
    class twa_succ_iterable
    {
    protected:
      const twa* aut_;
      twa_succ_iterator* it_;
    public:
      twa_succ_iterable(const twa* aut, twa_succ_iterator* it)
        : aut_(aut), it_(it)
      {
      }

      twa_succ_iterable(twa_succ_iterable&& other)
        : aut_(other.aut_), it_(other.it_)
      {
        other.it_ = nullptr;
      }

      ~twa_succ_iterable(); // Defined in this file after twa

      internal::succ_iterator begin()
      {
        return it_->first() ? it_ : nullptr;
      }

      internal::succ_iterator end()
      {
        return nullptr;
      }
    };
#endif // SWIG
555
  }
556

557
  /// \defgroup twa TωA (Transition-based ω-Automata)
558
  ///
559
  /// Spot is centered around the spot::twa type.  This type and its
560
  /// cousins are listed \ref twa_essentials "here".  This is an
561
  /// abstract interface.  Its implementations are either \ref
562 563 564
  /// twa_representation "concrete representations", or \ref
  /// twa_on_the_fly_algorithms "on-the-fly algorithms".  Other
  /// algorithms that work on spot::twa are \ref twa_algorithms
565 566
  /// "listed separately".

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
567
  /// \addtogroup twa_essentials Essential TωA types
568
  /// \ingroup twa
569

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
570
  /// \ingroup twa_essentials
571
  /// \brief A Transition-based ω-Automaton.
572
  ///
573 574 575 576
  /// The acronym TωA stands for Transition-based ω-automaton.
  /// We may write it as TwA or twa, but never as TWA as the
  /// w is just a non-utf8 replacement for ω that should not be
  /// capitalized.
577
  ///
578 579 580 581 582 583
  /// TωAs are transition-based automata, meanings that not-only do
  /// they have labels on edges, but they also have an acceptance
  /// condition defined in term of sets of transitions.  The
  /// acceptance condition can be anything supported by the HOA format
  /// (http://adl.github.io/hoaf/).  The only restriction w.r.t. the
  /// format is that this class does not support alternating automata.
584
  ///
585
  /// Previous versions of Spot supported a type of automata called
586
  /// TGBA, which are TωA in which the acceptance condition is a set
587
  /// of sets of transitions that must be visited infinitely often.
588 589
  ///
  /// In this version, TGBAs are now represented by TωAs for which
590
  ///
591 592 593 594 595 596 597 598
  ///     aut->acc().is_generalized_buchi()
  ///
  /// returns true.
  ///
  /// Browsing a TωA is usually achieved using two methods: \c
  /// get_init_state(), and succ().  The former returns the initial
  /// state while the latter allows iterating over the outgoing edges
  /// of any given state.
599
  ///
600
  /// Note that although this is a transition-based automata, we never
601
  /// represent edges in the API.  Information about edges can be
602 603
  /// obtained by querying the iterator over the successors of a
  /// state.
604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620
  ///
  /// The interface presented here is what we call the on-the-fly
  /// interface of automata, because the TωA class can be subclassed
  /// to implement an object that computes its successors on-the-fly.
  /// The down-side is that all these methods are virtual, so you you
  /// pay the cost of virtual calls when iterating over automata
  /// constructed on-the-fly.  Also the interface assumes that each
  /// successor state is a new object whose memory management is the
  /// responsibility of the caller, who should then call
  /// state::destroy() to release it.
  ///
  /// If you want to work with a TωA that is explicitly stored as a
  /// graph in memory, use the spot::twa_graph subclass instead.  A
  /// twa_graph object can be used as a spot::twa (using the
  /// on-the-fly interface, even though nothing needs to be
  /// constructed), but it also offers a faster interface that do not
  /// use virtual methods.
621
  class SPOT_API twa: public std::enable_shared_from_this<twa>
622
  {
623
  protected:
624
    twa(const bdd_dict_ptr& d);
625
    /// Any iterator returned via release_iter.
626
    mutable twa_succ_iterator* iter_cache_;
627
    /// BDD dictionary used by the automaton.
628
    bdd_dict_ptr dict_;
629
  public:
630

631
    virtual ~twa();
632

633 634 635
    /// \brief Get the initial state of the automaton.
    ///
    /// The state has been allocated with \c new.  It is the
636
    /// responsability of the caller to \c destroy it when no
637
    /// longer needed.
638
    virtual const state* get_init_state() const = 0;
639

640
    /// \brief Get an iterator over the successors of \a local_state.
641 642 643 644
    ///
    /// The iterator has been allocated with \c new.  It is the
    /// responsability of the caller to \c delete it when no
    /// longer needed.
645 646
    ///
    /// \see succ()
647
    virtual twa_succ_iterator*
648
    succ_iter(const state* local_state) const = 0;
649

650
#ifndef SWIG
651 652 653
    /// \brief Build an iterable over the successors of \a s.
    ///
    /// This is meant to be used as
654 655 656 657 658 659 660 661 662 663
    ///
    /// \code
    ///    for (auto i: aut->succ(s))
    ///      {
    ///        // use i->cond(), i->acc(), i->dst()
    ///      }
    /// \endcode
    ///
    /// and the above loop is in fact syntactic sugar for
    ///
664
    /// \code
665 666 667 668 669 670 671 672
    ///    twa_succ_iterator* i = aut->succ_iter(s);
    ///    if (i->first())
    ///      do
    ///        {
    ///          // use i->cond(), i->acc(), i->dst()
    ///        }
    ///      while (i->next());
    ///    aut->release_iter(i);
673
    /// \endcode
674
    internal::twa_succ_iterable
675 676 677 678
    succ(const state* s) const
    {
      return {this, succ_iter(s)};
    }
679
 #endif
680 681 682 683 684

    /// \brief Release an iterator after usage.
    ///
    /// This iterator can then be reused by succ_iter() to avoid
    /// memory allocation.
685
    void release_iter(twa_succ_iterator* i) const
686 687
    {
      if (iter_cache_)
688
        delete i;
689
      else
690
        iter_cache_ = i;
691
    }
692

693 694
    /// \brief Get the dictionary associated to the automaton.
    ///
695 696 697 698 699 700 701 702 703 704 705 706 707 708
    /// Automata are labeled by Boolean formulas over atomic
    /// propositions.  These Boolean formula are represented as BDDs.
    /// The dictionary allows to map BDD variables back to atomic
    /// propositions, and vice versa.
    ///
    /// Usually automata that are involved in the same computations
    /// should share their dictionaries so that operations between
    /// BDDs of the two automata work naturally.
    ///
    /// It is however possible to declare automata that use different
    /// sets of atomic propositions with different dictionaries.  That
    /// way a BDD variable associated to some atomic proposition in
    /// one automaton might be reused for another atomic proposition
    /// in the other automaton.
709 710
    bdd_dict_ptr get_dict() const
    {
711
      return dict_;
712
    }
713

714 715 716 717 718 719 720 721 722
    ///@{
    /// \brief Register an atomic proposition designated by \a ap.
    ///
    /// This is the preferred way to declare that an automaton is using
    /// a given atomic proposition.
    ///
    /// This adds the atomic proposition to the list of atomic
    /// proposition of the automaton, and also register it to the
    /// bdd_dict.
723
    ///
724 725
    /// \return The BDD variable number assigned for this atomic
    /// proposition.
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
726
    int register_ap(formula ap)
727
    {
728 729
      int res = dict_->has_registered_proposition(ap, this);
      if (res < 0)
730 731 732 733 734
        {
          aps_.push_back(ap);
          res = dict_->register_proposition(ap, this);
          bddaps_ &= bdd_ithvar(res);
        }
735 736 737
      return res;
    }

738
    int register_ap(std::string ap)
739
    {
740
      return register_ap(formula::ap(ap));
741
    }
742
    ///@}
743

744 745 746 747
    /// \brief Unregister an atomic proposition.
    ///
    /// \param num the BDD variable number returned by register_ap().
    void unregister_ap(int num);
748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775

    /// \brief Register all atomic propositions that have
    /// already be register by the bdd_dict for this automaton.
    ///
    /// This method may only be called on an automaton with an empty
    /// list of AP.  It will fetch all atomic proposition that have
    /// been set in the bdd_dict for this particular automaton.
    ///
    /// The typical use-case for this function is when the labels of
    /// an automaton are created by functions such as
    /// formula_to_bdd().  This is for instance done in the parser
    /// for never claims or LBTT.
    void register_aps_from_dict()
    {
      if (!aps_.empty())
        throw std::runtime_error("register_ap_from_dict() may not be"
                                 " called on an automaton that has already"
                                 " registered some AP");
      auto& m = get_dict()->bdd_map;
      unsigned s = m.size();
      for (unsigned n = 0; n < s; ++n)
        if (m[n].refs.find(this) != m[n].refs.end())
          {
            aps_.push_back(m[n].f);
            bddaps_ &= bdd_ithvar(n);
          }
    }

776
    /// \brief The vector of atomic propositions registered by this
777
    /// automaton.
778
    const std::vector<formula>& ap() const
779 780 781 782
    {
      return aps_;
    }

783
    /// \brief The set of atomic propositions as a conjunction.
784
    bdd ap_vars() const
785 786 787 788
    {
      return bddaps_;
    }

789 790
    /// \brief Format the state as a string for printing.
    ///
791 792 793 794 795
    /// Formating is the responsability of the automata that owns the
    /// state, so that state objects could be implemented as very
    /// small objects, maybe sharing data with other state objects via
    /// data structure stored in the automaton.
    virtual std::string format_state(const state* s) const = 0;
796

797
    /// \brief Project a state on an automaton.
798 799 800 801 802 803 804 805 806 807 808
    ///
    /// This converts \a s, into that corresponding spot::state for \a
    /// t.  This is useful when you have the state of a product, and
    /// want restrict this state to a specific automata occuring in
    /// the product.
    ///
    /// It goes without saying that \a s and \a t should be compatible
    /// (i.e., \a s is a state of \a t).
    ///
    /// \return 0 if the projection fails (\a s is unrelated to \a t),
    ///    or a new \c state* (the projected state) that must be
809
    ///    destroyed by the caller.
810
    virtual state* project_state(const state* s,
811
                                 const const_twa_ptr& t) const;
812

813 814
    ///@{
    /// \brief The acceptance condition of the automaton.
815 816 817 818
    const acc_cond& acc() const
    {
      return acc_;
    }
819

820 821 822 823
    acc_cond& acc()
    {
      return acc_;
    }
824
    ///@}
825

826
    /// \brief Check whether the language of the automaton is empty.
827 828
    virtual bool is_empty() const;

829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847
    /// \brief Return an accepting run if one exists.
    ///
    /// Note that this method currently one works for Fin-less
    /// acceptance.  For acceptance conditions that contain Fin
    /// acceptance, you can either rely on is_empty() and not use any
    /// accepting run, or remove Fin acceptance using remove_fin() and
    /// compute an accepting run on that larger automaton.
    ///
    /// Return nullptr if no accepting run were found.
    virtual twa_run_ptr accepting_run() const;

    /// \brief Return an accepting word if one exists.
    ///
    /// Note that this method DO works with Fin
    /// acceptance.
    ///
    /// Return nullptr if no accepting word were found.
    virtual twa_word_ptr accepting_word() const;

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
848
  private:
849 850
    acc_cond acc_;

851 852 853
    void set_num_sets_(unsigned num)
    {
      if (num < acc_.num_sets())
854 855 856 857
        {
          acc_.~acc_cond();
          new (&acc_) acc_cond;
        }
858 859 860
      acc_.add_sets(num - acc_.num_sets());
    }

861
  public:
862
    /// Number of acceptance sets used by the automaton.
863 864 865 866 867
    unsigned num_sets() const
    {
      return acc_.num_sets();
    }

868
    /// Acceptance formula used by the automaton.
869
    const acc_cond::acc_code& get_acceptance() const
870 871 872
    {
      return acc_.get_acceptance();
    }
873

874 875 876 877
    /// \brief Set the acceptance condition of the automaton.
    ///
    /// \param num the number of acceptance sets used
    /// \param c the acceptance formula
878 879
    void set_acceptance(unsigned num, const acc_cond::acc_code& c)
    {
880
      set_num_sets_(num);
881 882 883
      acc_.set_acceptance(c);
    }

884
    /// Copy the acceptance condition of another TωA.
885
    void copy_acceptance_of(const const_twa_ptr& a)
886 887 888 889
    {
      acc_ = a->acc();
    }

890
    /// Copy the atomic propositions of another TωA
891
    void copy_ap_of(const const_twa_ptr& a)
892
    {
893
      for (auto f: a->ap())
894
        this->register_ap(f);
895 896
    }

897 898 899 900 901 902 903 904 905 906 907 908
    /// \brief Set generalized Büchi acceptance
    ///
    /// \param num the number of acceptance sets to used
    ///
    /// The acceptance formula of the form
    /// \code
    /// Inf(0)&Inf(1)&...&Inf(num-1)
    /// \endcode
    /// is generated.
    ///
    /// In the case where \a num is null, the state-acceptance
    /// property is automatically turned on.
909 910 911 912 913 914
    void set_generalized_buchi(unsigned num)
    {
      set_num_sets_(num);
      acc_.set_generalized_buchi();
    }

915 916 917 918 919 920 921 922 923 924 925 926 927 928 929
    /// \brief Set Büchi acceptance.
    ///
    /// This declares a single acceptance set, and \c Inf(0)
    /// acceptance.  The returned mark \c {0} can be used to tag
    /// accepting transition.
    ///
    /// Note that this does not make the automaton as using
    /// state-based acceptance.  If you want to create a Büchi
    /// automaton with state-based acceptance, call
    /// \code
    /// prop_state_acc(true)
    /// \endcode
    /// in addition.
    ///
    /// \see prop_state_acc
930 931 932 933 934 935
    acc_cond::mark_t set_buchi()
    {
      set_generalized_buchi(1);
      return acc_.mark(0);
    }

936
  private:
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
937
    std::vector<formula> aps_;
938
    bdd bddaps_;
939

940
    /// Helper structure used to store property flags.
941 942
    struct bprop
    {
943 944
      trival::repr_t state_based_acc:2;   // State-based acceptance.
      trival::repr_t inherently_weak:2;   // Inherently Weak automaton.
945 946
      trival::repr_t weak:2;               // Weak automaton.
      trival::repr_t terminal:2;               // Terminal automaton.
947 948 949
      trival::repr_t deterministic:2;     // Deterministic automaton.
      trival::repr_t unambiguous:2;       // Unambiguous automaton.
      trival::repr_t stutter_invariant:2; // Stutter invariant language.
950 951 952 953 954 955 956
    };
    union
    {
      unsigned props;
      bprop is;
    };

957 958 959
#ifndef SWIG
    // Dynamic properties, are given with a name and a destructor function.
    std::unordered_map<std::string,
960 961
                       std::pair<void*,
                                 std::function<void(void*)>>> named_prop_;
962
#endif
963 964
    void* get_named_prop_(std::string s) const;

965 966
  public:

967
#ifndef SWIG
968 969
    /// \brief Declare a named property
    ///
970
    /// Arbitrary objects can be attached to automata.  Those are called
971 972 973
    /// named properties.  They are used for instance to name all the
    /// state of an automaton.
    ///
974 975 976
    /// This function attaches the object \a val to the current
    /// automaton, under the name \a s and destroy any previous
    /// property with the same name.
977 978 979
    ///
    /// When the automaton is destroyed, the \a destructor function will
    /// be called to destroy the attached object.
980 981 982
    ///
    /// See https://spot.lrde.epita.fr/concepts.html#named-properties
    /// for a list of named properties used by Spot.
983
    void set_named_prop(std::string s,
984
                        void* val, std::function<void(void*)> destructor);
985

986 987
    /// \brief Declare a named property
    ///
988
    /// Arbitrary objects can be attached to automata.  Those are called
989 990 991
    /// named properties.  They are used for instance to name all the
    /// state of an automaton.
    ///
992 993 994
    /// This function attaches the object \a val to the current
    /// automaton, under the name \a s and destroy any previous
    /// property with the same name.
995
    ///
996 997
    /// When the automaton is destroyed, the attached object will be
    /// destroyed with \c delete.
998 999 1000
    ///
    /// See https://spot.lrde.epita.fr/concepts.html#named-properties
    /// for a list of named properties used by Spot.
1001 1002 1003 1004 1005 1006
    template<typename T>
    void set_named_prop(std::string s, T* val)
    {
      set_named_prop(s, val, [](void *p) { delete static_cast<T*>(p); });
    }

1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018
    /// \brief Erase a named property
    ///
    /// Arbitrary objects can be attached to automata.  Those are called
    /// named properties.  They are used for instance to name all the
    /// state of an automaton.
    ///
    /// This function removes the property \a s if it exists.
    ///
    /// See https://spot.lrde.epita.fr/concepts.html#named-properties
    /// for a list of named properties used by Spot.
    void set_named_prop(std::string s, std::nullptr_t);

1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030
    /// \brief Retrieve a named property
    ///
    /// Because named property can be object of any type, retrieving
    /// the object requires knowing its type.
    ///
    /// \param s the name of the object to retrieve
    /// \tparam T the type of the object to retrieve
    ///
    /// Note that the return is a pointer to \c T, so the type should
    /// not include the pointer.
    ///
    /// Returns a nullptr if no such named property exists.
1031 1032 1033
    ///
    /// See https://spot.lrde.epita.fr/concepts.html#named-properties
    /// for a list of named properties used by Spot.
1034 1035 1036
    template<typename T>
    T* get_named_prop(std::string s) const
    {
1037 1038 1039
      if (void* p = get_named_prop_(s))
        return static_cast<T*>(p);
      else
1040
        return nullptr;
1041
    }
1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065

    /// \brief Create or retrieve a named property
    ///
    /// Arbitrary objects can be attached to automata.  Those are called
    /// named properties.  They are used for instance to name all the
    /// state of an automaton.
    ///
    /// This function create a property object of a given type, and
    /// attached it to \a name if not such property exist, or it
    /// returns
    ///
    /// See https://spot.lrde.epita.fr/concepts.html#named-properties
    /// for a list of named properties used by Spot.
    template<typename T>
    T* get_or_set_named_prop(std::string s)
    {
      if (void* p = get_named_prop_(s))
        return static_cast<T*>(p);

      auto tmp = new T;
      set_named_prop(s, tmp);
      return tmp;
    }

1066 1067
#endif

1068 1069 1070 1071
    /// \brief Destroy all named properties.
    ///
    /// This is used by the automaton destructor, but it could be used
    /// by any algorithm that want to get rid of all named properties.
1072 1073 1074 1075
    void release_named_properties()
    {
      // Destroy all named properties.
      for (auto& np: named_prop_)
1076
        np.second.second(np.second.first);
1077 1078 1079
      named_prop_.clear();
    }

1080 1081 1082 1083 1084 1085
    /// \brief Whether the automaton uses state-based acceptance.
    ///
    /// From the point of view of Spot, this means that all
    /// transitions leaving a state belong to the same acceptance
    /// sets.  Then it is equivalent to pretend that the state is in
    /// the acceptance set.
1086
    trival prop_state_acc() const
1087
    {
1088 1089
      if (num_sets() == 0)
        return true;
1090 1091 1092
      return is.state_based_acc;
    }

1093 1094 1095 1096
    /// \brief Set the state-based-acceptance property.
    ///
    /// If this property is set to true, then all transitions leaving
    /// a state must belong to the same acceptance sets.
1097
    void prop_state_acc(trival val)
1098
    {
1099
      is.state_based_acc = val.val();
1100 1101
    }

1102 1103 1104 1105
    /// \brief Whether this is a state-based Büchi automaton.
    ///
    /// An SBA has a Büchi acceptance, and should have its
    /// state-based acceptance property set.
1106
    trival is_sba() const
1107
    {
1108
      return prop_state_acc() && acc().is_buchi();
1109 1110
    }

1111 1112 1113 1114 1115 1116 1117 1118
    /// \brief Whether the automaton is inherently weak.
    ///
    /// An automaton is inherently weak if accepting cycles and
    /// rejecting cycles are never mixed in the same strongly
    /// connected component.
    ///
    /// \see prop_weak()
    /// \see prop_terminal()
1119
    trival prop_inherently_weak() const
1120 1121 1122 1123
    {
      return is.inherently_weak;
    }

1124 1125 1126 1127 1128 1129 1130
    /// \brief Set the "inherently weak" proeprty.
    ///
    /// Setting "inherently weak" to false automatically
    /// disables "terminal" and "weak".
    ///
    /// \see prop_weak()
    /// \see prop_terminal()
1131
    void prop_inherently_weak(trival val)
1132
    {
1133 1134
      is.inherently_weak = val.val();
      if (!val)
1135
        is.terminal = is.weak = val.val();
1136 1137
    }

1138 1139 1140 1141 1142 1143 1144 1145 1146
    /// \brief Whether the automaton is terminal.
    ///
    /// An automaton is terminal if it is weak, no non-accepting cycle
    /// can be reached from an accepting cycle, and the accepting
    /// strongly components are complete (i.e., any suffix is accepted
    /// as soon as we enter an accepting component).
    ///
    /// \see prop_weak()
    /// \see prop_inherently_weak()