// TR1 utility -*- C++ -*-

// Copyright (C) 2004, 2005 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library 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; either version 2, or (at your option)
// any later version.

// 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
// 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 License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.

/** @file 
 *  This is a TR1 C++ Library header. 
 */

#ifndef _TR1_UTILITY
#define _TR1_UTILITY 1

#include "../utility"

namespace std
{
namespace tr1
{
  template<class _Tp> class tuple_size;
  template<int _Int, class _Tp> class tuple_element;

   // Various functions which give std::pair a tuple-like interface.
  template<class _Tp1, class _Tp2>
    struct tuple_size<std::pair<_Tp1, _Tp2> >
    { static const int value = 2; };
 
  template<class _Tp1, class _Tp2>
    struct tuple_element<0, std::pair<_Tp1, _Tp2> >
    { typedef _Tp1 type; };
 
  template<class _Tp1, class _Tp2>
    struct tuple_element<1, std::pair<_Tp1, _Tp2> >
    { typedef _Tp2 type; };
 

  template<int _Int> struct __pair_get;

  template<>
    struct __pair_get<0>
    {
      template<typename _Tp1, typename _Tp2>
      static _Tp1& __get(std::pair<_Tp1, _Tp2>& __pair)
      { return __pair.first; }

      template<typename _Tp1, typename _Tp2>
      static const _Tp1& __const_get(const std::pair<_Tp1, _Tp2>& __pair)
      { return __pair.first; }
    };

  template<>
    struct __pair_get<1>
    {
      template<typename _Tp1, typename _Tp2>
      static _Tp2& __get(std::pair<_Tp1, _Tp2>& __pair)
      { return __pair.second; }

      template<typename _Tp1, typename _Tp2>
      static const _Tp2& __const_get(const std::pair<_Tp1, _Tp2>& __pair)
      { return __pair.second; }
    };

   template<int _Int, class _Tp1, class _Tp2>
     typename tuple_element<_Int, std::pair<_Tp1, _Tp2> >::type&
     get(pair<_Tp1, _Tp2>& __in)
     { return __pair_get<_Int>::__get(__in); }
 
   template<int _Int, class _Tp1, class _Tp2>
     const typename tuple_element<_Int, std::pair<_Tp1, _Tp2> >::type&
     get(const pair<_Tp1, _Tp2>& __in)
     { return __pair_get<_Int>::__const_get(__in); }
}
} 

#endif
