Add 2 benchmarks directories.

Add an algorithm to split an automaton in several automata.

* bench/scc-stats: New directory.  Contains input files and test
program for computing statistics.
* bench/split-product: New directory.  Contains test program for
synchronised product on splitted automata.
* bench/split-product/models: New directory.  Contains Promela
files and LTL formulae that should be verified by the models.
* src/tgba/tgbafromfile.cc, src/tgba/tgbafromfile.hh:
New files.  Small class to avoid long initializations with numerous
constants when translating to TGBA many LTL formulae from a
given file.
* src/tgbaalgos/cutscc.cc, src/tgbaalgos/cutscc.hh:
New file.  From a single automaton, create, at most,
X sub automata.
* src/tgbaalgos/scc.cc, src/tgbaalgos/scc.hh:
Adjust to compute self-loops count.

src/tgbaalgos/cutscc.hh

@@ -0,0 +1,47 @@
+// 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.
+
+
+#ifndef SPOT_TGBAALGOS_CUTSCC_HH
+# define SPOT_TGBAALGOS_CUTSCC_HH
+
+#include <iosfwd>
+#include <set>
+#include <vector>
+#include "tgba/public.hh"
+#include "tgbaalgos/scc.hh"
+
+namespace spot
+{
+  struct sccs_set
+  {
+    std::set<unsigned> sccs;
+    unsigned size;
+  };
+
+  std::vector<std::vector<sccs_set* > >* find_paths(tgba* a, const scc_map& m);
+  unsigned max_spanning_paths(std::vector<sccs_set* >* paths, scc_map& m);
+  std::list<tgba*> split_tgba(tgba* a, const scc_map& m,
+			      unsigned split_number);
+
+}
+
+#endif // SPOT_TGBAALGOS_CUTSCC_HH