snake_generic.hh

// Copyright (C) 2007, 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_CANVAS_BROWSING_SNAKE_GENERIC_HH
# define MLN_CANVAS_BROWSING_SNAKE_GENERIC_HH


# include <vector>
# include <mln/core/concept/browsing.hh>


namespace mln
{

  namespace canvas
  {

    namespace browsing
    {


      struct snake_generic_t : public Browsing< snake_generic_t >
      {

        template <typename F>
        void operator()(F& f) const;

      };

      extern const snake_generic_t snake_generic;

# ifndef MLN_INCLUDE_ONLY

      const snake_generic_t snake_generic;

      template <typename F>
      inline
      void
      snake_generic_t::operator()(F& f) const
      {
        trace::entering("canvas::browsing::snake_generic");
        mln_precondition(f.input.is_valid());

        // p init
        f.p = f.input.bbox().pmin();// - f.dps[0];

        std::vector< int > directions(f.moves.size(), 0);
        unsigned deph = 0;
        unsigned total_deph = f.moves.size() / 2 + 1;

        // initialization
        f.init();

        bool first = true;
        directions[deph] = 1;
        deph = total_deph - 1;

        // Call the move function (for the first point)
        (f.*(f.moves[(deph - 1) * 2 - 1 + directions[deph - 1]])) ();
        while (deph > 0) // If direction is empty, break
        {
          mln_assertion(deph <= total_deph);
          mln_assertion(deph > 0);
          // If f.p is near the border (we ended a direction) -> next child
          if (!f.input.domain().has(f.p +
                                    f.dps[(deph - 1) * 2 - 1 + directions[deph - 1]]))
          {
            // Go up the tree
            deph--;
            if (deph >= 1)
              // Change directions
              directions[deph] = directions[deph] == 1 ? 0 : 1;
            continue;
          }

          if (!first)
          {
            // Move f.p
            f.p += f.dps[(deph - 1) * 2 - 1 + directions[deph - 1]];
            // Call the move function
            (f.*(f.moves[(deph - 1) * 2 - 1 + directions[deph - 1]])) ();
          }
          else
            first = false;

          if (deph != total_deph)
          {
            // Go down the tree
            deph++;
            first = true;
          }
        }

        trace::exiting("canvas::browsing::snake_generic");
      }

# endif // ! MLN_INCLUDE_ONLY

    } // end of namespace mln::canvas::browsing

  } // end of namespace mln::canvas

} // end of namespace mln


#endif // ! MLN_CANVAS_BROWSING_SNAKE_GENERIC_HH