snake_generic.hh 4.55 KB
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// Copyright (C) 2007, 2008 EPITA Research and Development Laboratory
// (LRDE)
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//
// This file is part of the Olena Library.  This library is free
// software; you can redistribute it and/or modify it under the terms
// of the GNU General Public License version 2 as published by the
// Free Software Foundation.
//
// This library 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 this library; see the file COPYING.  If not, write to
// the Free Software Foundation, 51 Franklin Street, Fifth Floor,
// Boston, MA 02111-1307, USA.
//
// As a special exception, you may use this file as part of a free
// software library 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

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/// \file mln/canvas/browsing/snake_generic.hh
///
/// Browsing in a snake-way, forward.
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Guillaume Lazzara's avatar
Guillaume Lazzara committed
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# include <vector>
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# include <mln/core/concept/browsing.hh>

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namespace mln
{

  namespace canvas
  {

    namespace browsing
    {

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      /// Multidimentional Browsing in a given-way.
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      /*!
       * F shall feature: \n
       * { \n
       *   --- as attributes: \n
       *   input; \n
       *   p; \n
       *   --- as methods: \n
       *   void init(); \n
       *   void *() moves[]; \n
       *   dpsite dps[]; \n
       * } \n
       *
       * init is called before browsing
       *
       * The snake follow dimension using the delta point site of dps.
       *     dps[0] = delta psite following the global dimension (forward)
       *     dps[1] = delta psite following the 2nd dimension to follow (forward).
       *     dps[2] = delta psite following the 2nd dimension to follow (backward).
       *     dps[3] = delta psite following the 3nd dimension to follow (forward).
       *     dps[3] = delta psite following the 3nd dimension to follow (backward).
       *
       * moves contains pointer to f's members. These merbers will be call in each time
       * the snake progress in the correct dimension :
       *
       *      moves[i] is called at each move following the delta psite dps[i]
       *
       */

      struct snake_generic_t : public Browsing< snake_generic_t >
      {

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

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      };
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      extern const snake_generic_t snake_generic;
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# ifndef MLN_INCLUDE_ONLY

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      const snake_generic_t snake_generic;

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      template <typename F>
      inline
      void
      snake_generic_t::operator()(F& f) const
      {
	trace::entering("canvas::browsing::snake_generic");
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	mln_precondition(f.input.is_valid());
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	// p init
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	f.p = f.input.bbox().pmin();// - f.dps[0];
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	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--;
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	    if (deph >= 1)
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	      // 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