algebraic_n_face.hh

// Copyright (C) 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_TOPO_ALGEBRAIC_N_FACE_HH
# define MLN_TOPO_ALGEBRAIC_N_FACE_HH


#include <mln/topo/n_face.hh>


namespace mln
{

  namespace topo
  {

    /*-------------------.
    | Algebraic n-Face.  |
    `-------------------*/

    template <unsigned N, unsigned D>
    class algebraic_n_face : public n_face<N, D>
    {
      typedef n_face<N, D> super_;

    public:
      algebraic_n_face();
      algebraic_n_face(complex<D>& complex, unsigned face_id, bool sign);
      algebraic_n_face(const n_face<N, D>& f, bool sign);

      bool sign() const;
      void set_sign(bool sign);

    private:
      bool sign_;
    };


    template <unsigned N, unsigned D>
    algebraic_n_face<N, D>
    make_algebraic_n_face(const n_face<N, D>& f, bool sign);


    template <unsigned N, unsigned D>
    algebraic_n_face<N, D>
    operator-(const n_face<N, D>& f);

    template <unsigned N, unsigned D>
    algebraic_n_face<N, D>
    operator-(const algebraic_n_face<N, D>& f);



    template <unsigned N, unsigned D>
    bool
    operator==(const algebraic_n_face<N, D>& lhs,
               const algebraic_n_face<N, D>& rhs);

    template <unsigned N, unsigned D>
    bool
    operator!=(const algebraic_n_face<N, D>& lhs,
               const algebraic_n_face<N, D>& rhs);

    template <unsigned N, unsigned D>
    bool
    operator< (const algebraic_n_face<N, D>& lhs,
               const algebraic_n_face<N, D>& rhs);



    template <unsigned N, unsigned D>
    std::ostream&
    operator<<(std::ostream& ostr, const algebraic_n_face<N, D>& f);



    template <unsigned D>
    algebraic_n_face<1, D>
    edge(const n_face<0, D>& f1, const n_face<0, D>& f2);



# ifndef MLN_INCLUDE_ONLY

    template <unsigned N, unsigned D>
    inline
    algebraic_n_face<N, D>::algebraic_n_face()
      : super_(), sign_(true)
    {
      // Ensure N is compatible with D.
      metal::bool_< N <= D >::check();
      mln_postcondition(!this->is_valid());
    }

    template <unsigned N, unsigned D>
    inline
    algebraic_n_face<N, D>::algebraic_n_face(complex<D>& c, unsigned face_id,
                                             bool sign)
      : super_(c, face_id), sign_(sign)
    {
      // Ensure N is compatible with D.
      metal::bool_< N <= D >::check();
    }

    template <unsigned N, unsigned D>
    inline
    algebraic_n_face<N, D>::algebraic_n_face(const n_face<N, D>& f, bool sign)
      : super_(f), sign_(sign)
    {
      // Ensure N is compatible with D.
      metal::bool_< N <= D >::check();
    }


    template <unsigned N, unsigned D>
    inline
    bool
    algebraic_n_face<N, D>::sign() const
    {
      return sign_;
    }

    template <unsigned N, unsigned D>
    inline
    void
    algebraic_n_face<N, D>::set_sign(bool sign)
    {
      sign_ = sign;
    }


    template <unsigned N, unsigned D>
    algebraic_n_face<N, D>
    make_algebraic_n_face(const n_face<N, D>& f, bool sign)
    {
      return algebraic_n_face<N, D>(f, sign);
    }


    template <unsigned N, unsigned D>
    algebraic_n_face<N, D>
    operator-(const n_face<N, D>& f)
    {
      return algebraic_n_face<N, D>(f, false);
    }

    template <unsigned N, unsigned D>
    algebraic_n_face<N, D>
    operator-(const algebraic_n_face<N, D>& f)
    {
      algebraic_n_face<N, D> f2(f);
      f2.set_sign(!f.sign());
      return f2;
    }


    template <unsigned N, unsigned D>
    inline
    bool
    operator==(const algebraic_n_face<N, D>& lhs,
               const algebraic_n_face<N, D>& rhs)
    {
      // Ensure LHS and RHS belong to the same complex.
      mln_precondition(lhs.cplx() == rhs.cplx());
      return lhs.face_id() == rhs.face_id() && lhs.sign() == rhs.sign();
    }

    template <unsigned N, unsigned D>
    inline
    bool
    operator!=(const algebraic_n_face<N, D>& lhs,
               const algebraic_n_face<N, D>& rhs)
    {
      // Ensure LHS and RHS belong to the same complex.
      mln_precondition(lhs.cplx() == rhs.cplx());
      return !(lhs == rhs);
    }

    template <unsigned N, unsigned D>
    inline
    bool
    operator< (const algebraic_n_face<N, D>& lhs,
               const algebraic_n_face<N, D>& rhs)
    {
      // Ensure LHS and RHS belong to the same complex.
      mln_precondition(lhs.cplx() == rhs.cplx());
      return lhs.face_id() < rhs.face_id();
    }


    template <unsigned N, unsigned D>
    inline
    std::ostream&
    operator<<(std::ostream& ostr, const algebraic_n_face<N, D>& f)
    {
      return
        ostr << "(cplx = " << f.cplx().addr() << ", dim = " << f.n()
             << ", id = " << f.face_id() << ", sign = " << f.sign()<< ')';
    }

    /*----------.
    | Helpers.  |
    `----------*/

    template <unsigned D>
    algebraic_n_face<1, D>
    edge(const n_face<0, D>& f1, const n_face<0, D>& f2)
    {
      typedef std::vector< algebraic_n_face<0, D> > n0_faces_t;
      typedef std::vector< algebraic_n_face<1, D> > n1_faces_t;

      n1_faces_t f1_adj_edges = f1.higher_dim_adj_faces();
      for (typename n1_faces_t::const_iterator e = f1_adj_edges.begin();
           e != f1_adj_edges.end(); ++e)
        {
          n0_faces_t e_adj_vertices = e->lower_dim_adj_faces();
          for (typename n0_faces_t::const_iterator w = e_adj_vertices.begin();
               w != e_adj_vertices.end(); ++w)
            if (*w == f2)
              // E is the edge linking F1 and F2.
              return *e;
        }

      // If no shared edge was found, retun an empty (invalid) 1-face.
      return algebraic_n_face<1, D>();
    }

# endif // ! MLN_INCLUDE_ONLY

  } // end of namespace mln::topo

} // end of namespace mln

#endif // ! MLN_TOPO_ALGEBRAIC_N_FACE_HH