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- // Move, forward and identity for C++0x + swap -*- C++ -*-
- // Copyright (C) 2007-2015 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
- #if __cplusplus >= 201103L
- #include <type_traits> // Brings in std::declval too.
- namespace std _GLIBCXX_VISIBILITY(default)
- {
- _GLIBCXX_BEGIN_NAMESPACE_VERSION
- /**
- * @addtogroup utilities
- * @{
- */
- /**
- * @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>
- 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.
- /**
- * @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); }
- // C++11 version of std::exchange for internal use.
- 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;
- }
- /// @} 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)
- #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.
- /// Swap the contents of two arrays.
- 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]);
- }
- /// @} group utilities
- _GLIBCXX_END_NAMESPACE_VERSION
- } // namespace
- #endif /* _MOVE_H */
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