move.h

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

// Copyright (C) 2007-2013 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/>.

#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.
  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

#if __cplusplus >= 201103L
#include <type_traits> // Brings in std::declval too.

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

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

  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);
    }

  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 { };

  template<typename _Tp>
    inline constexpr 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.

  template<typename _Tp>
    inline _Tp*
    addressof(_Tp& __r) noexcept
    { return std::__addressof(__r); }

_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

  template<typename _Tp>
    inline void
    swap(_Tp& __a, _Tp& __b)
#if __cplusplus >= 201103L
    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.
  template<typename _Tp, size_t _Nm>
    inline void
    swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm])
#if __cplusplus >= 201103L
    noexcept(noexcept(swap(*__a, *__b)))
#endif
    {
      for (size_t __n = 0; __n < _Nm; ++__n)
    swap(__a[__n], __b[__n]);
    }

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif /* _MOVE_H */