* src/misc/minato.cc, src/misc/minato.hh: New files.

* src/misc/Makefile.am (misc_HEADERS, libmisc_la_SOURCES): Add them.
* src/tgbaalgos/ltl2tgba_fm.cc (ltl_to_tgba_fm): Use minato_isop.

src/misc/minato.hh

@@ -0,0 +1,65 @@
+#ifndef SPOT_MISC_MINATO_HH
+# define SPOT_MISC_MINATO_HH
+
+# include <bdd.h>
+# include <stack>
+
+namespace spot
+{
+  /// \brief Generate an irredundant sum-of-products (ISOP) form of a
+  /// BDD function.
+  ///
+  /// This algorithm implements a derecursived version the Minato-Morreale
+  /// algorithm presented in the following paper.
+  /// \verbatim
+  /// @InProceedings{   minato.92.sasimi,
+  ///   author        = {Shin-ichi Minato},
+  ///   title         = {Fast Generation of Irredundant Sum-of-Products Forms
+  ///                   from Binary Decision Diagrams},
+  ///   booktitle     = {Proceedings of the third Synthesis and Simulation
+  ///                   and Meeting International Interchange workshop
+  ///                   (SASIMI'92)},
+  ///   pages         = {64--73},
+  ///   year          = {1992},
+  ///   address       = {Kobe, Japan},
+  ///   month         = {April}
+  /// }
+  /// \endverbatim
+  class minato_isop
+  {
+  public:
+    /// \brief Conctructor.
+    /// \arg input The BDD function to translate in ISOP.
+    minato_isop(bdd input);
+    /// \brief Compute the next sum term of the ISOP form.
+    /// Return \c bddfalse when all terms have been output.
+    bdd next();
+
+  private:
+    /// Internal variables for minato_isop.
+    struct local_vars
+    {
+      // If you are following the paper, f_min and f_max corresponds
+      // to the pair of BDD function used to encode the ternary function `f'
+      // (see Section 3.4).
+      // Also note that f0, f0', and f0'' all share the same _max function.
+      // Likewise for f1, f1', and f1''.
+      bdd f_min, f_max;
+      // Because we need a non-recursive version of the algorithm,
+      // we had to split it in four step (each step is separated
+      // from the other by a call to ISOP in the original algorithm).
+      enum { FirstStep, SecondStep, ThirdStep, FourthStep } step;
+      bdd v1;
+      bdd f0_min, f0_max;
+      bdd f1_min, f1_max;
+      bdd g0, g1;
+      local_vars(bdd f_min, bdd f_max)
+	: f_min(f_min), f_max(f_max), step(FirstStep) {}
+    };
+    std::stack<local_vars> todo;
+    std::stack<bdd> cube;
+    bdd ret;
+  };
+}
+
+#endif // SPOT_MISC_MINATO_HH