// <utility> -*- C++ -*-

// Copyright (C) 2001-2013 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 3, 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.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1996,1997
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */

/** @file include/utility
 *  This is a Standard C++ Library header. 
 */

#ifndef _GLIBCXX_UTILITY
#define _GLIBCXX_UTILITY 1

#pragma GCC system_header

/**
 * @defgroup utilities Utilities
 *
 * Components deemed generally useful. Includes pair, tuple,
 * forward/move helpers, ratio, function object, metaprogramming and
 * type traits, time, date, and memory functions.
 */

#include <bits/c++config.h>
#include <bits/stl_relops.h>
#include <bits/stl_pair.h>

#if __cplusplus >= 201103L
#include <bits/move.h>
#include <initializer_list>

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  template<class _Tp>
    class tuple_size;

  template<std::size_t _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>>
    : public integral_constant<std::size_t, 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<std::size_t _Int>
    struct __pair_get;

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

      template<typename _Tp1, typename _Tp2>
        static constexpr _Tp1&&
        __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
        { return std::forward<_Tp1>(__pair.first); }

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

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

      template<typename _Tp1, typename _Tp2>
        static constexpr _Tp2&&
        __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
        { return std::forward<_Tp2>(__pair.second); }

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

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

  template<std::size_t _Int, class _Tp1, class _Tp2>
    constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
    get(std::pair<_Tp1, _Tp2>&& __in) noexcept
    { return __pair_get<_Int>::__move_get(std::move(__in)); }

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

#if __cplusplus > 201103L
  template <typename _Tp, typename _Up>
    constexpr _Tp&
    get(pair<_Tp, _Up>& __p) noexcept
    { return __p.first; }

  template <typename _Tp, typename _Up>
    constexpr const _Tp&
    get(const pair<_Tp, _Up>& __p) noexcept
    { return __p.first; }

  template <typename _Tp, typename _Up>
    constexpr _Tp&&
    get(pair<_Tp, _Up>&& __p) noexcept
    { return std::move(__p.first); }

  template <typename _Tp, typename _Up>
    constexpr _Tp&
    get(pair<_Up, _Tp>& __p) noexcept
    { return __p.second; }

  template <typename _Tp, typename _Up>
    constexpr const _Tp&
    get(const pair<_Up, _Tp>& __p) noexcept
    { return __p.second; }

  template <typename _Tp, typename _Up>
    constexpr _Tp&&
    get(pair<_Up, _Tp>&& __p) noexcept
    { return std::move(__p.second); }

  /// Assign @p __new_val to @p __obj and return its previous value.
  template <typename _Tp, typename _Up = _Tp>
    inline _Tp
    exchange(_Tp& __obj, _Up&& __new_val)
    {
      _Tp __old_val = std::move(__obj);
      __obj = std::forward<_Up>(__new_val);
      return __old_val;
    }
#endif

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif

#endif /* _GLIBCXX_UTILITY */
