sigma.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
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// Public License.

#ifndef OLENA_TOPO_COMBINATORIAL_MAP_INTERNAL_SIGMA_HH
# define OLENA_TOPO_COMBINATORIAL_MAP_INTERNAL_SIGMA_HH

# include <oln/topo/combinatorial-map/internal/anyfunc.hh>
# include <oln/topo/combinatorial-map/internal/alpha.hh>

# include <mlc/contract.hh>

# include <vector>

namespace oln {

  namespace topo {

    namespace combinatorial_map {

      namespace internal {

        /* sigma function
        **
        ** \todo Add doc.
        */
        template <class U>
        class sigma : public anyfunc< U, U, sigma<U> >
        {
        public:
          static std::string
          name()
          {
            return "sigma";
          }

          void
          resize_(unsigned n)
          {
            f_.resize(n+1);
            f_1_.resize(n+1);
          }

          void
          assign_(const U & i, const U & e)
          {
            assertion(e < f_1_.size());

            f_[i] = e;
            f_1_[e] = i;
          }

          void
          erase_(const U & d)
          {
            f_[f_1_[d]] = f_[d];
            f_1_[f_[d]] = f_1_[d];
            f_[d] = f_1_[d] = 0;

            unsigned d_ = alpha<U>::result(d);
            f_[f_1_[d_]] = f_[d_];
            f_1_[f_[d_]] = f_1_[d_];
            f_[d_] = f_1_[d_] = 0;
          }

        private:
          std::vector<U> f_1_;
        };

      } // end of namespace internal

    } // end of namespace combinatorial_map

  } // end of namespace topo

} // end of namespace oln

#endif // ! OLENA_TOPO_COMBINATORIAL_MAP_INTERNAL_SIGMA_HH

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