ord_pair.hh

// Copyright (C) 2007, 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_UTIL_ORD_PAIR_HH
# define MLN_UTIL_ORD_PAIR_HH


# include <mln/core/concept/object.hh>
# include <mln/util/ord.hh>


namespace mln
{

  namespace util
  {

    //
    template <typename T>
    struct ord_pair : public mln::Object< ord_pair<T> >
    {
    public:
      ord_pair();
      ord_pair(const T& val1, const T& val2);

    public:
      const T& first() const;
      T& first();

      const T& second() const;
      T& second();

      void change_first(const T& val);

      void change_second(const T& val);

      void change_both(const T& first, const T& second);

    private:
      T first_;
      T second_;
    };


    template <typename T>
    bool operator==(const ord_pair<T>& lhs, const ord_pair<T>& rhs);

    template <typename T>
    bool operator< (const ord_pair<T>& lhs, const ord_pair<T>& rhs);

    template <typename T>
    bool operator<=(const ord_pair<T>& lhs, const ord_pair<T>& rhs);


    template <typename T>
    std::ostream& operator<<(std::ostream& ostr, const ord_pair<T>& op);

  } // end of namespace mln::util


  namespace make
  {
    template <typename T>
    util::ord_pair<T> ord_pair(const T& val1, const T& val2);
  }


# ifndef MLN_INCLUDE_ONLY

  namespace util
  {

    /*---------------.
    | Construction.  |
    `---------------*/

    template <typename T>
    inline
    ord_pair<T>::ord_pair()
    {
    }

    template <typename T>
    inline
    ord_pair<T>::ord_pair(const T& val1, const T& val2)
    {
      change_both(val1, val2);
    }

    /*---------.
    | Access.  |
    `---------*/

    template <typename T>
    inline
    const T&
    ord_pair<T>::first() const
    {
      return first_;
    }

    template <typename T>
    inline
    T&
    ord_pair<T>::first()
    {
      return first_;
    }

    template <typename T>
    inline
    const T&
    ord_pair<T>::second() const
    {
      return second_;
    }

    template <typename T>
    inline
    T&
    ord_pair<T>::second()
    {
      return second_;
    }

    template <typename T>
    inline
    void
    ord_pair<T>::change_first(const T& val)
    {
      mln_precondition(util::ord_weak(first_, second_));

      if (util::ord_strict(val, second_))
        first_ = val;
      else
        second_ = val;

      mln_postcondition(util::ord_weak(first_, second_));
    }

    template <typename T>
    inline
    void
    ord_pair<T>::change_second(const T& val)
    {
      mln_precondition(util::ord_weak(first_, second_));

      if (util::ord_strict(first_, val))
        second_ = val;
      else
        first_ = val;

      mln_postcondition(util::ord_weak(first_, second_));
    }

    template <typename T>
    inline
    void
    ord_pair<T>::change_both(const T& val1, const T& val2)
    {
      if (util::ord_strict(val1, val2))
        {
          first_  = val1;
          second_ = val2;
        }
      else
        {
          first_  = val2;
          second_ = val1;
        }
      mln_postcondition(util::ord_weak(first_, second_));
    }

    /*-------------.
    | Comparison.  |
    `-------------*/

    template <typename T>
    inline
    bool operator==(const ord_pair<T>& lhs, const ord_pair<T>& rhs)
    {
      return lhs.first() == rhs.first() && lhs.second() == rhs.second();
    }

    template <typename T>
    inline
    bool operator< (const ord_pair<T>& lhs, const ord_pair<T>& rhs)
    {
      return
        util::ord_strict(lhs.first(), rhs.first()) ||
        (lhs.first() == rhs.first() &&
         util::ord_strict(lhs.second(), rhs.second()));
    }

    template <typename T>
    inline
    bool operator<=(const ord_pair<T>& lhs, const ord_pair<T>& rhs)
    {
      return
        util::ord_strict(lhs.first(), rhs.first()) ||
        (lhs.first() == rhs.first() &&
         util::ord_weak(lhs.second(), rhs.second()));
    }

    /*------------------.
    | Pretty-printing.  |
    `------------------*/

    template <typename T>
    inline
    std::ostream& operator<<(std::ostream& ostr, const ord_pair<T>& op)
    {
      return ostr << '(' << op.first() << ',' << op.second() << ')';
    }

  } // end of namespace mln::util


  namespace make
  {

    template <typename T>
    inline
    util::ord_pair<T>
    ord_pair(const T& val1, const T& val2)
    {
      util::ord_pair<T> tmp(val1, val2);
      return tmp;
    }

  } // end of namespace mln::make

# endif // ! MLN_INCLUDE_ONLY

} // end of namespace mln


#endif // ! MLN_UTIL_ORD_PAIR_HH