new transformation from Fin-less to TGBA

Fixes #72.

* src/tgbaalgos/totgba.cc, src/tgbaalgos/totgba.hh: New files.
* src/tgbaalgos/Makefile.am: Add them.
* src/tgbaalgos/postproc.cc, src/tgbaalgos/postproc.hh: Add
a Generic output type, and call to_generalized_buchi() if
this type is not selected.
* src/tgbatest/remfin.test: Add some tests.
* src/bin/autfilt.cc: Add a --generic option, and set it
by default.

src/tgbaalgos/totgba.cc

@@ -0,0 +1,94 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2015 Laboratoire de Recherche et Développement
+// de l'Epita.
+//
+// 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 3 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include "totgba.hh"
+#include "remfin.hh"
+#include "cleanacc.hh"
+#include "tgba/tgbagraph.hh"
+
+namespace spot
+{
+  namespace
+  {
+    typedef std::vector<acc_cond::mark_t> terms_t;
+
+    terms_t cnf_terms(const acc_cond::acc_code& code)
+    {
+      assert(!code.empty());
+      terms_t res;
+      auto pos = &code.back();
+      auto end = &code.front();
+      if (pos->op == acc_cond::acc_op::And)
+	--pos;
+      while (pos >= end)
+	{
+	  auto term_end = pos - 1 - pos->size;
+	  if (pos->op == acc_cond::acc_op::Or)
+	    --pos;
+	  acc_cond::mark_t m = 0U;
+	  while (pos > term_end)
+	    {
+	      assert(pos->op == acc_cond::acc_op::Inf);
+	      m |= pos[-1].mark;
+	      pos -= 2;
+	    }
+	  res.push_back(m);
+	}
+      return res;
+    }
+  }
+
+
+
+  /// \brief Take an automaton with any acceptance condition and return
+  /// an equivalent Generalized Büchi automaton.
+  tgba_digraph_ptr
+  to_generalized_buchi(const const_tgba_digraph_ptr& aut)
+  {
+    auto res = remove_fin(cleanup_acceptance(aut));
+    if (res->acc().is_generalized_buchi())
+      return res;
+
+    auto cnf = res->get_acceptance().to_cnf();
+    // If we are very lucky, building a CNF actually gave us a GBA...
+    if (cnf.empty() ||
+	(cnf.size() == 2 && cnf.back().op == acc_cond::acc_op::Fin))
+      {
+	res->set_acceptance(res->acc().num_sets(), cnf);
+	cleanup_acceptance_here(res);
+	return res;
+      }
+
+    auto terms = cnf_terms(cnf);
+    unsigned nterms = terms.size();
+    assert(nterms > 0);
+    res->set_generalized_buchi(nterms);
+
+    for (auto& t: res->transitions())
+      {
+	acc_cond::mark_t cur_m = t.acc;
+	acc_cond::mark_t new_m = 0U;
+	for (unsigned n = 0; n < nterms; ++n)
+	  if (cur_m & terms[n])
+	    new_m.set(n);
+	t.acc = new_m;
+      }
+    return res;
+  }
+}