complex_relative_iterator_sequence.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_INTERNAL_COMPLEX_RELATIVE_ITERATOR_SEQUENCE_HH
# define MLN_TOPO_INTERNAL_COMPLEX_RELATIVE_ITERATOR_SEQUENCE_HH


# include <iosfwd>

# include <mln/metal/equal.hh>

# include <mln/core/concept/iterator.hh>
# include <mln/topo/complex.hh>


namespace mln
{

  namespace topo
  {

    namespace internal
    {

      template <typename I1>
      struct const_face_type_
      {
        typedef typename I1::face_type F_;
        typedef const F_& ret;
      };


      template <typename I1, typename I2, typename E>
      class complex_relative_iterator_sequence : public Iterator<E>
      {
        typedef complex_relative_iterator_sequence<I1, I2, E> self_;

      public:
        typedef typename I1::center_type center_type;
        typedef typename I1::face_type face_type;

        complex_relative_iterator_sequence();
        template <typename Fref>
        complex_relative_iterator_sequence(const Fref& f_ref);

        void center_at(const center_type& c);

        bool is_valid() const;
        void invalidate();

        void start();
        void next_();

        operator typename const_face_type_<I1>::ret () const;
        //      that is:  const face_type&

      protected:
        void update_();

      protected:
        I1 iter1_;
        I2 iter2_;

        face_type f_;
      };


      template <typename I1, typename I2, typename E>
      inline
      std::ostream&
      operator<<(std::ostream& ostr,
                 const complex_relative_iterator_sequence<I1, I2, E>& p);



# ifndef MLN_INCLUDE_ONLY

      template <typename I1, typename I2, typename E>
      inline
      complex_relative_iterator_sequence<I1, I2, E>::complex_relative_iterator_sequence()
      {
        // Ensure I1 and I2 are compatible.
        mlc_equal(typename I1::face_type, typename I2::face_type)::check();

        invalidate();
      }

      template <typename I1, typename I2, typename E>
      template <typename Fref>
      inline
      complex_relative_iterator_sequence<I1, I2, E>::complex_relative_iterator_sequence(const Fref& f_ref)
      {
        // Ensure I1 and I2 are compatible.
        mlc_equal(typename I1::face_type, typename I2::face_type)::check();

        center_at(f_ref);
      }

      template <typename I1, typename I2, typename E>
      inline
      void
      complex_relative_iterator_sequence<I1, I2, E>::center_at(const center_type& c)
      {
        iter1_.center_at(c);
        iter2_.center_at(c);
        invalidate();
      }

      template <typename I1, typename I2, typename E>
      inline
      bool
      complex_relative_iterator_sequence<I1, I2, E>::is_valid() const
      {
        return iter1_.is_valid() || iter2_.is_valid();
      }

      template <typename I1, typename I2, typename E>
      inline
      void
      complex_relative_iterator_sequence<I1, I2, E>::invalidate()
      {
        iter1_.invalidate();
        iter2_.invalidate();
      }

      template <typename I1, typename I2, typename E>
      inline
      void
      complex_relative_iterator_sequence<I1, I2, E>::start()
      {
        iter1_.start();
        iter2_.start();
        if (is_valid())
          update_();
      }

      template <typename I1, typename I2, typename E>
      inline
      void
      complex_relative_iterator_sequence<I1, I2, E>::next_()
      {
        /* Iterator<E>::next() ensures that either iter1_ or iter2_
           (or both) are valid before executing this method.  */
        if (iter1_.is_valid())
          iter1_.next();
        else
          iter2_.next();
        if (is_valid())
          update_();
      }

      template <typename I1, typename I2, typename E>
      inline
      void
      complex_relative_iterator_sequence<I1, I2, E>::update_()
      {
        mln_precondition(is_valid());
        if (iter1_.is_valid())
          f_ = iter1_;
        else
          f_ = iter2_;
      }

      template <typename I1, typename I2, typename E>
      inline
      complex_relative_iterator_sequence<I1, I2, E>::operator typename const_face_type_<I1>::ret () const
      {
        return f_;
      }


      template <typename I1, typename I2, typename E>
      inline
      std::ostream&
      operator<<(std::ostream& ostr,
                 const complex_relative_iterator_sequence<I1, I2, E>& p)
      {
        return ostr << typename I1::face_type(p);
      }

# endif // ! MLN_INCLUDE_ONLY

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

  } // end of namespace mln::topo

} // end of namespace mln

#endif // ! MLN_TOPO_INTERNAL_COMPLEX_RELATIVE_ITERATOR_SEQUENCE_HH