libstdc++
|
00001 // Move, forward and identity for C++0x + swap -*- C++ -*- 00002 00003 // Copyright (C) 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file bits/move.h 00026 * This is an internal header file, included by other library headers. 00027 * Do not attempt to use it directly. @headername{utility} 00028 */ 00029 00030 #ifndef _MOVE_H 00031 #define _MOVE_H 1 00032 00033 #include <bits/c++config.h> 00034 #include <bits/concept_check.h> 00035 00036 namespace std _GLIBCXX_VISIBILITY(default) 00037 { 00038 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00039 00040 // Used, in C++03 mode too, by allocators, etc. 00041 /** 00042 * @brief Same as C++11 std::addressof 00043 * @ingroup utilities 00044 */ 00045 template<typename _Tp> 00046 inline _Tp* 00047 __addressof(_Tp& __r) _GLIBCXX_NOEXCEPT 00048 { 00049 return reinterpret_cast<_Tp*> 00050 (&const_cast<char&>(reinterpret_cast<const volatile char&>(__r))); 00051 } 00052 00053 _GLIBCXX_END_NAMESPACE_VERSION 00054 } // namespace 00055 00056 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00057 #include <type_traits> // Brings in std::declval too. 00058 00059 namespace std _GLIBCXX_VISIBILITY(default) 00060 { 00061 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00062 00063 /** 00064 * @addtogroup utilities 00065 * @{ 00066 */ 00067 00068 // forward (as per N3143) 00069 /** 00070 * @brief Forward an lvalue. 00071 * @return The parameter cast to the specified type. 00072 * 00073 * This function is used to implement "perfect forwarding". 00074 */ 00075 template<typename _Tp> 00076 constexpr _Tp&& 00077 forward(typename std::remove_reference<_Tp>::type& __t) noexcept 00078 { return static_cast<_Tp&&>(__t); } 00079 00080 /** 00081 * @brief Forward an rvalue. 00082 * @return The parameter cast to the specified type. 00083 * 00084 * This function is used to implement "perfect forwarding". 00085 */ 00086 template<typename _Tp> 00087 constexpr _Tp&& 00088 forward(typename std::remove_reference<_Tp>::type&& __t) noexcept 00089 { 00090 static_assert(!std::is_lvalue_reference<_Tp>::value, "template argument" 00091 " substituting _Tp is an lvalue reference type"); 00092 return static_cast<_Tp&&>(__t); 00093 } 00094 00095 /** 00096 * @brief Convert a value to an rvalue. 00097 * @param __t A thing of arbitrary type. 00098 * @return The parameter cast to an rvalue-reference to allow moving it. 00099 */ 00100 template<typename _Tp> 00101 constexpr typename std::remove_reference<_Tp>::type&& 00102 move(_Tp&& __t) noexcept 00103 { return static_cast<typename std::remove_reference<_Tp>::type&&>(__t); } 00104 00105 00106 template<typename _Tp> 00107 struct __move_if_noexcept_cond 00108 : public __and_<__not_<is_nothrow_move_constructible<_Tp>>, 00109 is_copy_constructible<_Tp>>::type { }; 00110 00111 /** 00112 * @brief Conditionally convert a value to an rvalue. 00113 * @param __x A thing of arbitrary type. 00114 * @return The parameter, possibly cast to an rvalue-reference. 00115 * 00116 * Same as std::move unless the type's move constructor could throw and the 00117 * type is copyable, in which case an lvalue-reference is returned instead. 00118 */ 00119 template<typename _Tp> 00120 inline typename 00121 conditional<__move_if_noexcept_cond<_Tp>::value, const _Tp&, _Tp&&>::type 00122 move_if_noexcept(_Tp& __x) noexcept 00123 { return std::move(__x); } 00124 00125 // declval, from type_traits. 00126 00127 /** 00128 * @brief Returns the actual address of the object or function 00129 * referenced by r, even in the presence of an overloaded 00130 * operator&. 00131 * @param __r Reference to an object or function. 00132 * @return The actual address. 00133 */ 00134 template<typename _Tp> 00135 inline _Tp* 00136 addressof(_Tp& __r) noexcept 00137 { return std::__addressof(__r); } 00138 00139 /// @} group utilities 00140 _GLIBCXX_END_NAMESPACE_VERSION 00141 } // namespace 00142 00143 #define _GLIBCXX_MOVE(__val) std::move(__val) 00144 #define _GLIBCXX_FORWARD(_Tp, __val) std::forward<_Tp>(__val) 00145 #else 00146 #define _GLIBCXX_MOVE(__val) (__val) 00147 #define _GLIBCXX_FORWARD(_Tp, __val) (__val) 00148 #endif 00149 00150 namespace std _GLIBCXX_VISIBILITY(default) 00151 { 00152 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00153 00154 /** 00155 * @addtogroup utilities 00156 * @{ 00157 */ 00158 00159 /** 00160 * @brief Swaps two values. 00161 * @param __a A thing of arbitrary type. 00162 * @param __b Another thing of arbitrary type. 00163 * @return Nothing. 00164 */ 00165 template<typename _Tp> 00166 inline void 00167 swap(_Tp& __a, _Tp& __b) 00168 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00169 noexcept(__and_<is_nothrow_move_constructible<_Tp>, 00170 is_nothrow_move_assignable<_Tp>>::value) 00171 #endif 00172 { 00173 // concept requirements 00174 __glibcxx_function_requires(_SGIAssignableConcept<_Tp>) 00175 00176 _Tp __tmp = _GLIBCXX_MOVE(__a); 00177 __a = _GLIBCXX_MOVE(__b); 00178 __b = _GLIBCXX_MOVE(__tmp); 00179 } 00180 00181 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00182 // DR 809. std::swap should be overloaded for array types. 00183 /// Swap the contents of two arrays. 00184 template<typename _Tp, size_t _Nm> 00185 inline void 00186 swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm]) 00187 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00188 noexcept(noexcept(swap(*__a, *__b))) 00189 #endif 00190 { 00191 for (size_t __n = 0; __n < _Nm; ++__n) 00192 swap(__a[__n], __b[__n]); 00193 } 00194 00195 /// @} group utilities 00196 _GLIBCXX_END_NAMESPACE_VERSION 00197 } // namespace 00198 00199 #endif /* _MOVE_H */