find_root.hh

// Copyright (C) 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_MORPHO_INTERNAL_FIND_ROOT_HH
# define MLN_CANVAS_MORPHO_INTERNAL_FIND_ROOT_HH


# include <mln/core/concept/image.hh>

namespace mln
{

  namespace canvas
  {

    namespace morpho
    {

      namespace internal
      {

          template <typename I>
          inline
          mln_psite(I)
          find_root(I& parent, const mln_psite(I)& x);


          template <typename I>
          inline
          unsigned
          find_root_fastest(I& parent, unsigned x);


# ifndef MLN_INCLUDE_ONLY


          template <typename I>
          inline
          mln_psite(I)
          find_root(I& parent, const mln_psite(I)& x)
          {
            if (parent(x) == x)
              return x;
            else
              return parent(x) = find_root(parent, parent(x));
          }


          template <typename I>
          inline
          unsigned
          find_root_fastest(I& parent, unsigned x)
          {
            if (parent.element(x) == 0)
              return x;
            else
              return parent.element(x) = find_root_fastest(parent,
                                                           parent.element(x));
          }


# endif // ! MLN_INCLUDE_ONLY

      } // end of namespace mln::canvas::morpho::internal

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

  } // end of namespace mln::canvas

} // end of namespace mln

#endif // ! MLN_CANVAS_MORPHO_INTERNAL_FIND_ROOT_HH