spot/src/tgbaalgos/emptiness.cc

// Copyright (C) 2004  Laboratoire d'Informatique de Paris 6 (LIP6),
// département Systèmes Répartis Coopératifs (SRC), Université Pierre
// et Marie Curie.
//
// 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.

#include <sstream>
#include "emptiness.hh"
#include "tgba/tgba.hh"
#include "tgba/bddprint.hh"
#include "tgba/tgbaexplicit.hh"

namespace spot
{

  tgba_run::~tgba_run()
  {
    for (steps::const_iterator i = prefix.begin(); i != prefix.end(); ++i)
      delete i->s;
    for (steps::const_iterator i = cycle.begin(); i != cycle.end(); ++i)
      delete i->s;
  }

  tgba_run::tgba_run(const tgba_run& run)
  {
    for (steps::const_iterator i = run.prefix.begin();
	 i != run.prefix.end(); ++i)
      {
	step s = { s.s->clone(), i->label, i->acc };
	prefix.push_back(s);
      }
    for (steps::const_iterator i = run.cycle.begin();
	 i != run.cycle.end(); ++i)
      {
	step s = { s.s->clone(), i->label, i->acc };
	cycle.push_back(s);
      }
  }

  std::ostream& print_tgba_run(std::ostream& os,
			       const tgba* a,
			       const tgba_run* run)
  {
    bdd_dict* d = a->get_dict();
    os << "Prefix:" << std::endl;
    for (tgba_run::steps::const_iterator i = run->prefix.begin();
	 i != run->prefix.end(); ++i)
      {
	os << "  " << a->format_state(i->s) << std::endl;
	os << "  |  ";
	bdd_print_formula(os, d, i->label);
	os << "\t";
	bdd_print_accset(os, d, i->acc);
	os << std::endl;
      }
    os << "Cycle:" << std::endl;
    for (tgba_run::steps::const_iterator i = run->cycle.begin();
	 i != run->cycle.end(); ++i)
      {
	os << "  " << a->format_state(i->s) << std::endl;
	os << "  |  ";
	bdd_print_formula(os, d, i->label);
	os << "\t";
	bdd_print_accset(os, d, i->acc);
	os << std::endl;
      }
    return os;
  }

  tgba_run&
  tgba_run::operator=(const tgba_run& run)
  {
    if (&run != this)
      {
	this->~tgba_run();
	new(this) tgba_run(run);
      }
    return *this;
  }


  tgba_run*
  emptiness_check_result::accepting_run()
  {
    return 0;
  }

  emptiness_check::~emptiness_check()
  {
  }

  std::ostream&
  emptiness_check::print_stats(std::ostream& os) const
  {
    return os;
  }

  namespace
  {
    std::string format_state(const tgba* a, const state* s, int n)
    {
      std::ostringstream os;
      os << a->format_state(s) << " (" << n << ")";
      return os.str();
    }
  }

  tgba* tgba_run_to_tgba(const tgba* a, const tgba_run* run)
  {
    tgba_explicit* res = new tgba_explicit(a->get_dict());
    res->copy_acceptance_conditions_of(a);

    const state* s = a->get_init_state();
    int number = 1;
    tgba_explicit::state* source;
    tgba_explicit::state* dest;
    const tgba_run::steps* l;
    bdd seen_acc = bddfalse;

    typedef Sgi::hash_map<const state*, tgba_explicit::state*,
                          state_ptr_hash, state_ptr_equal> state_map;
    state_map seen;

    if (run->prefix.empty())
        l = &run->cycle;
    else
        l = &run->prefix;

    tgba_run::steps::const_iterator i = l->begin();

    assert(s->compare(i->s) == 0);
    source = res->set_init_state(format_state(a, i->s, number));
    ++number;
    seen.insert(std::make_pair(i->s, source));

    for (; i != l->end();)
      {
        // expected outgoing transition
        bdd label = i->label;
        bdd acc = i->acc;

        // compute the next expected state
        const state* next;
        ++i;
        if (i != l->end())
          {
            next = i->s;
          }
        else
          {
            if (l == &run->prefix)
              {
                l = &run->cycle;
                i = l->begin();
              }
            next = l->begin()->s;
          }

        // browse the actual outgoing transitions
        tgba_succ_iterator* j = a->succ_iter(s);
        delete s;
        for (j->first(); !j->done(); j->next())
          {
            if (j->current_condition() != label
                || j->current_acceptance_conditions() != acc)
              continue;

            const state* s2 = j->current_state();
            if (s2->compare(next) != 0)
              {
                delete s2;
                continue;
              }
            else
              {
                s = s2;
                break;
              }
          }
        assert(!j->done());
        delete j;

        state_map::const_iterator its = seen.find(next);
        if (its == seen.end())
          {
            dest = res->add_state(format_state(a, next, number));
            ++number;
            seen.insert(std::make_pair(next, dest));
          }
        else
          dest = its->second;

        tgba_explicit::transition* t = res->create_transition(source, dest);
        res->add_conditions(t, label);
        res->add_acceptance_conditions(t, acc);
        source = dest;

        // Sum acceptance conditions.
        if (l == &run->cycle && i != l->begin())
            seen_acc |= acc;
      }
    delete s;

    assert(seen_acc == a->all_acceptance_conditions());

    res->merge_transitions();

    return res;
  }

}