dir.hh

// Copyright (C) 2001, 2002, 2003, 2004  EPITA Research and Development Laboratory
//
// 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, 59 Temple Place - Suite 330, 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 OLENA_TOPO_INTER_PIXEL_INTERNAL_DIR_HH
# define OLENA_TOPO_INTER_PIXEL_INTERNAL_DIR_HH

# include <oln/config/system.hh>

# include <iostream>

namespace oln {

  namespace topo {

    namespace inter_pixel {
      namespace internal {
        template<unsigned Dim>
        struct dir_traits
        {};
        template<>
        struct dir_traits<2>
        {
          typedef enum dir { east, north, west, south } ret;

          static ret
          first()
          {
            return east;
          }

          static ret
          last()
          {
            return south;
          }
          static ret
          prev(ret i)
          {
            return i == first() ? last() : ret(i - 1);
          }

          static ret
          next(ret i)
          {
            return i == last() ? first() : ret(i + 1);
          }

          static ret
          opposite(ret i)
          {
            return ret((i + 2) % 4);
          }
        };
# define oln_dir_traits_type(ImgType)                           \
oln::topo::inter_pixel::internal::dir_traits< ImgType::dim >

# define oln_dir_type(ImgType)                  \
typename oln_dir_traits_type(ImgType)::ret

      } // end of namespace internal

    } // end of namespace inter_pixel

  } // end of namespace topo

} // end of namespace oln

std::ostream & operator<<(std::ostream& o,
                          oln::topo::inter_pixel::internal::dir_traits<2>::ret i)
{
  typedef oln::topo::inter_pixel::internal::dir_traits<2> traits;

  switch (i)
    {
    case traits::east: return o << "east";
    case traits::north: return o << "north";
    case traits::west: return o << "west";
    case traits::south: return o << "south";
    default: return o;
    }
}

#endif // !OLENA_TOPO_INTER_PIXEL_INTERNAL_DIR_HH

---