Quick implementation of a "useless SCC" filter using scc_map.

* src/tgbaalgos/sccfilter.hh, src/tgbaalgos/sccfilter.cc: New
files.
* src/tgbaalgos/Makefile.am: Add them.

ChangeLog

+2009-11-18  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
+
+	Quick implementation of a "useless SCC" filter using scc_map.
+
+	* src/tgbaalgos/sccfilter.hh, src/tgbaalgos/sccfilter.cc: New
+	files.
+	* src/tgbaalgos/Makefile.am: Add them.
+
 2009-11-18  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
 
 	Fix acceptance check in scc_map: trivial SCCs are not accepting.

src/tgbaalgos/Makefile.am

@@ -52,6 +52,7 @@ tgbaalgos_HEADERS = \
   rundotdec.hh \
   save.hh \
   scc.hh \
+  sccfilter.hh \
   se05.hh \
   stats.hh \
   tau03.hh \
@@ -85,6 +86,7 @@ libtgbaalgos_la_SOURCES = \
   rundotdec.cc \
   save.cc \
   scc.cc \
+  sccfilter.cc \
   se05.cc \
   stats.cc \
   tau03.cc \

src/tgbaalgos/sccfilter.cc

+// Copyright (C) 2009 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.
+
+#include "sccfilter.hh"
+#include "tgba/tgbaexplicit.hh"
+#include "reachiter.hh"
+#include "tgbaalgos/scc.hh"
+#include <sstream>
+
+namespace spot
+{
+  namespace
+  {
+    class filter_iter: public tgba_reachable_iterator_depth_first
+    {
+    public:
+      filter_iter(const tgba* a,
+		  const scc_map& sm,
+		  const std::vector<bool>& useless)
+	: tgba_reachable_iterator_depth_first(a),
+	  out_(new tgba_explicit_string(a->get_dict())),
+	  sm_(sm),
+	  useless_(useless)
+
+      {
+	out_->copy_acceptance_conditions_of(a);
+      }
+
+      tgba_explicit_string*
+      result()
+      {
+	return out_;
+      }
+
+      bool
+      want_state(const state* s) const
+      {
+	return !useless_[sm_.scc_of_state(s)];
+      }
+
+      void
+      process_link(const state* in_s, int in,
+		   const state* out_s, int out,
+		   const tgba_succ_iterator* si)
+      {
+	std::ostringstream in_name;
+	in_name << "(#" << in << ") " << this->automata_->format_state(in_s);
+	std::ostringstream out_name;
+	out_name << "(#" << out << ") " << this->automata_->format_state(out_s);
+
+	tgba_explicit::transition* t =
+	  out_->create_transition(in_name.str(), out_name.str());
+	out_->add_conditions(t, si->current_condition());
+
+	// Do not output any acceptance condition if either the source or
+	// the destination state do not belong to an accepting state.
+	if (sm_.accepting(sm_.scc_of_state(in_s))
+	    && sm_.accepting(sm_.scc_of_state(out_s)))
+	  out_->add_acceptance_conditions(t,
+					  si->current_acceptance_conditions());
+      }
+
+    private:
+      tgba_explicit_string* out_;
+      const scc_map& sm_;
+      const std::vector<bool>& useless_;
+    };
+  } // anonymous
+
+
+  tgba* scc_filter(const tgba* aut)
+  {
+    scc_map sm(aut);
+    sm.build_map();
+    scc_stats ss = build_scc_stats(sm);
+
+    filter_iter fi(aut, sm, ss.useless_scc_map);
+    fi.run();
+    return fi.result();
+  }
+
+
+
+}

src/tgbaalgos/sccfilter.hh

+// Copyright (C) 2009 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.
+
+#ifndef SPOT_TGBAALGOS_SCCFILTER_HH
+# define SPOT_TGBAALGOS_SCCFILTER_HH
+
+#include "tgba/tgba.hh"
+
+namespace spot
+{
+
+  // Prune unaccepting SCCs and remove superfluous acceptance conditions.
+  tgba* scc_filter(const tgba* aut);
+
+}
+
+#endif // SPOT_TGBAALGOS_SCC_HH