Add a new, parameterized, version of the Couvreur emptiness check.

This version has optimization for explicit twa, and also for weak and
terminal (depending on whether an accepting run is requested) automata.

* spot/twaalgos/couvreurnew.hh, spot/twaalgos/couvreurnew.cc,
  spot/twaalgos/Makefile.am: New files for the new algorithm.
* spot/twaalgos/emptiness.cc, tests/core/randtgba.cc:
  Register new algorithm.

spot/twaalgos/couvreurnew.hh

@@ -0,0 +1,49 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2016 Laboratoire de Recherche et Developpement 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/>.
+
+#pragma once
+
+#include <spot/twaalgos/emptiness.hh>
+
+namespace spot
+{
+  /// \brief A rewritten version of the Couvreur emptiness check.
+  ///
+  /// It is optimized to run on explicit automata (avoiding the memory
+  /// allocations of the virtual, abstract interface.
+  /// It also has specializations for weak and terminal automata.
+  SPOT_API
+  emptiness_check_ptr
+  get_couvreur99_new(const const_twa_ptr& a, option_map o);
+
+  /// \brief Same as above, but always uses the abstract interface.
+  ///
+  /// This function is provided to test the efficiency of specializing our
+  /// algorithms for explicit automata. It uses the same optimizations for
+  /// weak and terminal automata as the one above.
+  SPOT_API
+  emptiness_check_ptr
+  get_couvreur99_new_abstract(const const_twa_ptr& a, option_map o);
+
+  /// \brief A shortcut to run the optimized emptiness check directly.
+  ///
+  /// This is the same as get_couvreur99_new(a, {})->check().
+  SPOT_API
+  emptiness_check_result_ptr
+  couvreur99_new_check(const const_twa_ptr& a);
+}