site_iterator_base.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_CORE_INTERNAL_SITE_ITERATOR_BASE_HH
# define MLN_CORE_INTERNAL_SITE_ITERATOR_BASE_HH



# include <mln/core/concept/site_iterator.hh>
# include <mln/core/concept/pseudo_site.hh> // Use of if_possible::change_target.



namespace mln
{

  namespace internal
  {

    template <typename S, typename E>
    struct site_iterator_base : Site_Iterator<E>,
                                proxy_impl< const mln_psite(S)&, E>
    {
      typedef S target;

      typedef mln_site(S) site;

      const mln_site(S)& to_site() const;


      // Technical note:
      //
      //   A conversion operator towards the site it designates is
      //   not required since it is inherited from 'proxy_impl'.
      //   Defining '::operator mln_site(S)() const' here can lead to
      //   ambiguities in very special cases since we inherit a couple
      //   of conversions (const and non-const)


      const mln_psite(S)& subj_();

      const S*& target_();

    protected:

      site_iterator_base();

      const S* s_;

    private:

      typedef proxy_impl< const mln_psite(S)&, E> super_;
    };


#ifndef MLN_INCLUDE_ONLY

    template <typename S, typename E>
    inline
    site_iterator_base<S, E>::site_iterator_base()
      : s_(0)
    {
    }

    template <typename S, typename E>
    inline
    const mln_site(S)&
    site_iterator_base<S, E>::to_site() const
    {
      mln_precondition(exact(*this).is_valid());
      return this->get_subject();
    }

    template <typename S, typename E>
    inline
    const mln_psite(S)&
    site_iterator_base<S, E>::subj_()
    {
      return exact(this)->p_hook_();
    }

    template <typename S, typename E>
    inline
    const S*&
    site_iterator_base<S, E>::target_()
    {
      return s_;
    }

#endif // ! MLN_INCLUDE_ONLY

  } // end of namespace internal

} // end of namespace mln


#endif // ! MLN_CORE_INTERNAL_SITE_ITERATOR_BASE_HH