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// Move, forward and identity for C++0x + swap -*- C++ -*-

// Copyright (C) 2007, 2008, 2009, 2010, 2011 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/>.

/** @file bits/move.h

 *  This is an internal header file, included by other library headers.

 *  Do not attempt to use it directly. @headername{utility}

 */

#ifndef _MOVE_H

#define _MOVE_H 1

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

#include <bits/concept_check.h>

namespace std _GLIBCXX_VISIBILITY(default)

{

_GLIBCXX_BEGIN_NAMESPACE_VERSION

  // Used, in C++03 mode too, by allocators, etc.

  /**

   *  @brief Same as C++11 std::addressof

   *  @ingroup utilities

   */

  template<typename _Tp>

    inline _Tp*

    __addressof(_Tp& __r) _GLIBCXX_NOEXCEPT

    {

      return reinterpret_cast<_Tp*>

        (&const_cast<char&>(reinterpret_cast<const volatile char&>(__r)));

    }

_GLIBCXX_END_NAMESPACE_VERSION

} // namespace

#ifdef __GXX_EXPERIMENTAL_CXX0X__

#include <type_traits> // Brings in std::declval too.

namespace std _GLIBCXX_VISIBILITY(default)

{

_GLIBCXX_BEGIN_NAMESPACE_VERSION

  /**

   *  @addtogroup utilities

   *  @{

   */

  // forward (as per N3143)

  /**

   *  @brief  Forward an lvalue.

   *  @return The parameter cast to the specified type.

   *

   *  This function is used to implement "perfect forwarding".

   */

  template<typename _Tp>

    constexpr _Tp&&

    forward(typename std::remove_reference<_Tp>::type& __t) noexcept

    { return static_cast<_Tp&&>(__t); }

  /**

   *  @brief  Forward an rvalue.

   *  @return The parameter cast to the specified type.

   *

   *  This function is used to implement "perfect forwarding".

   */

  template<typename _Tp>

    constexpr _Tp&&

    forward(typename std::remove_reference<_Tp>::type&& __t) noexcept

    {

      static_assert(!std::is_lvalue_reference<_Tp>::value, "template argument"

                    " substituting _Tp is an lvalue reference type");

      return static_cast<_Tp&&>(__t);

    }

  /**

   *  @brief  Convert a value to an rvalue.

   *  @param  __t  A thing of arbitrary type.

   *  @return The parameter cast to an rvalue-reference to allow moving it.

  */

  template<typename _Tp>

    constexpr typename std::remove_reference<_Tp>::type&&

    move(_Tp&& __t) noexcept

    { return static_cast<typename std::remove_reference<_Tp>::type&&>(__t); }

  template<typename _Tp>

    struct __move_if_noexcept_cond

    : public __and_<__not_<is_nothrow_move_constructible<_Tp>>,

                    is_copy_constructible<_Tp>>::type { };

  /**

   *  @brief  Conditionally convert a value to an rvalue.

   *  @param  __x  A thing of arbitrary type.

   *  @return The parameter, possibly cast to an rvalue-reference.

   *

   *  Same as std::move unless the type's move constructor could throw and the

   *  type is copyable, in which case an lvalue-reference is returned instead.

   */

  template<typename _Tp>

    inline typename

    conditional<__move_if_noexcept_cond<_Tp>::value, const _Tp&, _Tp&&>::type

    move_if_noexcept(_Tp& __x) noexcept

    { return std::move(__x); }

  // declval, from type_traits.

  /**

   *  @brief Returns the actual address of the object or function

   *         referenced by r, even in the presence of an overloaded

   *         operator&.

   *  @param  __r  Reference to an object or function.

   *  @return   The actual address.

  */

  template<typename _Tp>

    inline _Tp*

    addressof(_Tp& __r) noexcept

    { return std::__addressof(__r); }

  /// @} group utilities

_GLIBCXX_END_NAMESPACE_VERSION

} // namespace

#define _GLIBCXX_MOVE(__val) std::move(__val)

#define _GLIBCXX_FORWARD(_Tp, __val) std::forward<_Tp>(__val)

#else

#define _GLIBCXX_MOVE(__val) (__val)

#define _GLIBCXX_FORWARD(_Tp, __val) (__val)

#endif

namespace std _GLIBCXX_VISIBILITY(default)

{

_GLIBCXX_BEGIN_NAMESPACE_VERSION

  /**

   *  @addtogroup utilities

   *  @{

   */

  /**

   *  @brief Swaps two values.

   *  @param  __a  A thing of arbitrary type.

   *  @param  __b  Another thing of arbitrary type.

   *  @return   Nothing.

  */

  template<typename _Tp>

    inline void

    swap(_Tp& __a, _Tp& __b)

#ifdef __GXX_EXPERIMENTAL_CXX0X__

    noexcept(__and_<is_nothrow_move_constructible<_Tp>,

                    is_nothrow_move_assignable<_Tp>>::value)

#endif

    {

      // concept requirements

      __glibcxx_function_requires(_SGIAssignableConcept<_Tp>)

      _Tp __tmp = _GLIBCXX_MOVE(__a);

      __a = _GLIBCXX_MOVE(__b);

      __b = _GLIBCXX_MOVE(__tmp);

    }

  // _GLIBCXX_RESOLVE_LIB_DEFECTS

  // DR 809. std::swap should be overloaded for array types.

  /// Swap the contents of two arrays.

  template<typename _Tp, size_t _Nm>

    inline void

    swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm])

#ifdef __GXX_EXPERIMENTAL_CXX0X__

    noexcept(noexcept(swap(*__a, *__b)))

#endif

    {

      for (size_t __n = 0; __n < _Nm; ++__n)

        swap(__a[__n], __b[__n]);

    }

  /// @} group utilities

_GLIBCXX_END_NAMESPACE_VERSION

} // namespace

#endif /* _MOVE_H */