adj_m_face_iter.hh

// Copyright (C) 2008, 2009 EPITA Research and Development Laboratory (LRDE)
//
// This file is part of Olena.
//
// Olena 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, version 2 of the License.
//
// Olena 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 Olena.  If not, see <http://www.gnu.org/licenses/>.
//
// As a special exception, you may use this file as part of a free
// software project without restriction.  Specifically, if other files
// instantiate templates or use macros or inline functions from this
// file, or you compile this file and link it with other files to produce
// an executable, this file does not by itself cause the resulting
// executable to be covered by the GNU General Public License.  This
// exception does not however invalidate any other reasons why the
// executable file might be covered by the GNU General Public License.

#ifndef MLN_TOPO_ADJ_M_FACE_ITER_HH
# define MLN_TOPO_ADJ_M_FACE_ITER_HH


# include <set>
# include <vector>

# include <mln/topo/internal/complex_relative_iterator_base.hh>
# include <mln/topo/face.hh>


namespace mln
{

  namespace topo
  {

    // Forward declarations.
    template <unsigned D> class complex;
    namespace internal
    {
      template <unsigned D> class adj_m_face_iterator;
    }


    /*-------------------------------.
    | topo::adj_m_face_fwd_iter<D>.  |
    `-------------------------------*/

    template <unsigned D>
    class adj_m_face_fwd_iter
      : public internal::forward_complex_relative_iterator_base< topo::face<D>,
                                                                 algebraic_face<D>,
                                                                 adj_m_face_fwd_iter<D> >,
        public internal::adj_m_face_iterator<D>
    {
      // Tech note: we use topo::face to help g++-2.95.
    private:
      typedef adj_m_face_fwd_iter<D> self_;
      typedef internal::forward_complex_relative_iterator_base< topo::face<D>,
                                                                algebraic_face<D>,
                                                                self_ > super_;
      typedef internal::adj_m_face_iterator<D> impl_;

    public:
      adj_m_face_fwd_iter();
      template <typename Fref>
      adj_m_face_fwd_iter(const Fref& f_ref, unsigned m);

      void update_adj_faces_();
    };


    /*-------------------------------.
    | topo::adj_m_face_bkd_iter<D>.  |
    `-------------------------------*/

    template <unsigned D>
    class adj_m_face_bkd_iter
      : public internal::backward_complex_relative_iterator_base< topo::face<D>,
                                                                  algebraic_face<D>,
                                                                  adj_m_face_bkd_iter<D> >,
        public internal::adj_m_face_iterator<D>
    {
      // Tech note: we use topo::face to help g++-2.95.
    private:
      typedef adj_m_face_bkd_iter<D> self_;
      typedef internal::backward_complex_relative_iterator_base< topo::face<D>,
                                                                 algebraic_face<D>,
                                                                 self_ > super_;
      typedef internal::adj_m_face_iterator<D> impl_;

    public:
      adj_m_face_bkd_iter();
      template <typename Fref>
      adj_m_face_bkd_iter(const Fref& f_ref, unsigned m);

      void update_adj_faces_();
    };


    /*-----------------------------------------.
    | topo::internal::adj_m_face_iterator<D>.  |
    `-----------------------------------------*/

    namespace internal
    {

      template <unsigned D>
      class adj_m_face_iterator
      {
      protected:
        adj_m_face_iterator();
        adj_m_face_iterator(unsigned m);

      public:
        unsigned m() const;
        void set_m(unsigned m);

      protected:
        void update_adj_faces__(const topo::face<D>& center,
                                std::vector< algebraic_face<D> >& adj_faces);

        unsigned m_;
      };

    } // end of namespace mln::topo::internal



# ifndef MLN_INCLUDE_ONLY

    /*-------------------------------.
    | topo::adj_m_face_fwd_iter<D>.  |
    `-------------------------------*/

    template <unsigned D>
    inline
    adj_m_face_fwd_iter<D>::adj_m_face_fwd_iter()
    {
    }

    template <unsigned D>
    template <typename Fref>
    inline
    adj_m_face_fwd_iter<D>::adj_m_face_fwd_iter(const Fref& f_ref, unsigned m)
      : super_(f_ref), impl_(m)
    {
    }

    template <unsigned D>
    inline
    void
    adj_m_face_fwd_iter<D>::update_adj_faces_()
    {
      mln_precondition(this->c_);
      // Delegate computation to base class.
      this->update_adj_faces__(*this->c_, this->adj_faces_);
    }


    /*-------------------------------.
    | topo::adj_m_face_bkd_iter<D>.  |
    `-------------------------------*/

    template <unsigned D>
    inline
    adj_m_face_bkd_iter<D>::adj_m_face_bkd_iter()
    {
    }

    template <unsigned D>
    template <typename Fref>
    inline
    adj_m_face_bkd_iter<D>::adj_m_face_bkd_iter(const Fref& f_ref, unsigned m)
      : super_(f_ref), impl_(m)
    {
    }

    template <unsigned D>
    inline
    void
    adj_m_face_bkd_iter<D>::update_adj_faces_()
    {
      mln_precondition(this->c_);
      // Delegate computation to base class.
      this->update_adj_faces__(*this->c_, this->adj_faces_);
    }


    /*-----------------------------------------.
    | topo::internal::adj_m_face_iterator<D>.  |
    `-----------------------------------------*/

    namespace internal
    {

      template <unsigned D>
      inline
      adj_m_face_iterator<D>::adj_m_face_iterator()
        : m_(0)
      {
      }

      template <unsigned D>
      inline
      adj_m_face_iterator<D>::adj_m_face_iterator(unsigned m)
        : m_(m)
      {
        mln_precondition(m <= D);
      }

      template <unsigned D>
      unsigned
      adj_m_face_iterator<D>::m() const
      {
        return m_;
      }

      template <unsigned D>
      void
      adj_m_face_iterator<D>::set_m(unsigned m)
      {
        m_ = m;
      }

      template <unsigned D>
      inline
      void
      adj_m_face_iterator<D>::update_adj_faces__(const topo::face<D>& center,
                                                 std::vector< algebraic_face<D> >& adj_faces)
      {
        adj_faces.clear();

        if (center.n() == m_)
          return;

        typedef std::vector < topo::algebraic_face<D> > faces_t;
        typedef std::set < topo::algebraic_face<D> > faces_set_t;

        /* FIXME: p_faces is redundant; we could use adj_faces
           directly.  */
        /* The adjacent p-faces being built; initialized with CENTER,
           and filled with q-faces at each step, until q reaches
           m_.  */
        faces_t p_faces(1,
                        make_algebraic_face(center, true));
        // The set of faces being built.
        /* FIXME: This pattern is recurring in Milena---using an
           std::set (or any fast associative container) to improve
           the lookup speed of an std::vector; we should create a
           class for this, a bit like mln::util::set, but with a
           garantee on the order of insertion.  */
        faces_t work_faces;
        faces_set_t work_faces_set;

        // Iteratively compute the set of locations.
        for (unsigned p = center.n(); p != m_; (p < m_ ? ++p : --p) )
          {
            mln_invariant (p != m_);
            for (typename faces_t::const_iterator g = p_faces.begin();
                 g != p_faces.end(); ++g)
              {
                mln_invariant (g->n() != m_);
                faces_t q_faces = g->n() < m_ ?
                  g->higher_dim_adj_faces() :
                  g->lower_dim_adj_faces();
                /* Traverse the higher- or lower-dimension adjacent
                   faces of G in the natural order if G's sign is
                   positive, or in the reverse order if G's sign is
                   negative.  */
                /* FIXME: Factor; the code if the two branches is the
                   same, except for the iteration order. */
                if (g->sign())
                  {
                    for (typename faces_t::const_iterator h = q_faces.begin();
                         h != q_faces.end(); ++h)
                      // Don't insert a face twice.
                      if (work_faces_set.find(*h) == work_faces_set.end())
                        {
                          work_faces.push_back(*h);
                          work_faces_set.insert(*h);
                        }
                  }
                else
                  {
                    for (typename faces_t::const_reverse_iterator h =
                           q_faces.rbegin();
                         /* This is crazy.  With Apple g++ 4.0, this
                            code won't compile without this cast!
                            This is solved in MacPorts g++ 4.3.  */
                         h != (typename faces_t::const_reverse_iterator) q_faces.rend();
                         ++h)
                      // Don't insert a face twice.
                      if (work_faces_set.find(*h) == work_faces_set.end())
                        {
                          work_faces.push_back(*h);
                          work_faces_set.insert(*h);
                        }
                  }
              }
            work_faces.swap(p_faces);
            work_faces.clear();
            work_faces_set.clear();
          }

        adj_faces = p_faces;
      }

    } // end of namespace mln::topo::internal

# endif // ! MLN_INCLUDE_ONLY

  } // end of namespace mln::topo

} // end of namespace mln

#endif // ! MLN_TOPO_ADJ_M_FACE_ITER_HH