Add an algorithm to complement Büchi automata.

* src/tgba/tgbacomplement.hh, src/tgba/tgbacomplement.cc: New
	files. The complementation algorithm.
	* src/tgba/Makefile.am: Adjust.
	* src/tgbatest/complementation.test,
	src/tgbatest/complementation.cc: New files. Test suite for the
	complementation algorithm.
	* src/tgbatest/Makefile.am: Adjust.
	* src/tgbaalgos/Makefile.am: Reformat the header using 80
	columns.

src/tgba/tgbacomplement.hh

@@ -0,0 +1,68 @@
+#ifndef SPOT_TGBA_TGBACOMPLEMENT_HH
+# define SPOT_TGBA_TGBACOMPLEMENT_HH
+
+# include "tgba/tgba.hh"
+
+namespace spot
+{
+  struct safra_tree_automaton;
+
+  /// \brief Build a complemented automaton.
+  /// \ingroup tgba
+  ///
+  /// It creates an automaton that recognizes the
+  /// negated language of \a aut.
+  ///
+  /// 1. First Safra construction algorithm produces a
+  ///    deterministic Rabin automaton.
+  /// 2. Interpreting this deterministic Rabin automaton as a
+  ///    deterministic Streett will produce a complemented automaton.
+  /// 3. Then we use a transformation from deterministic Streett
+  ///    automaton to nondeterministic Büchi automaton.
+  ///
+  ///  Safra construction is done in \a tgba_complement, the transformation
+  ///  is done on-the-fly when successors are called.
+  ///
+  /// \sa safra_determinisation, tgba_complement::succ_iter.
+  class tgba_complement : public tgba
+  {
+  public:
+    tgba_complement(const tgba* a);
+    virtual ~tgba_complement();
+
+    safra_tree_automaton* get_safra() const
+    {
+      return safra_;
+    }
+
+    // tgba interface.
+    virtual state* get_init_state() const;
+    virtual tgba_succ_iterator*
+    succ_iter(const state* local_state,
+	      const state* global_state = 0,
+	      const tgba* global_automaton = 0) const;
+
+    virtual bdd_dict* get_dict() const;
+    virtual std::string format_state(const state* state) const;
+    virtual bdd all_acceptance_conditions() const;
+    virtual bdd neg_acceptance_conditions() const;
+
+  protected:
+    virtual bdd compute_support_conditions(const state* state) const;
+    virtual bdd compute_support_variables(const state* state) const;
+  private:
+    const tgba* automaton_;
+    safra_tree_automaton* safra_;
+    bdd the_acceptance_cond_;
+  };
+
+  /// \brief Produce a dot output of the Safra automaton associated
+  /// to \a a.
+  ///
+  /// @param a The \c tgba_complement with an intermediate Safra
+  /// automaton to display
+  ///
+  void display_safra(const tgba_complement* a);
+}
+
+#endif  // SPOT_TGBA_TGBACOMPLEMENT_HH