1 // Move, forward and identity for C++0x + swap -*- C++ -*- 2 3 // Copyright (C) 2007, 2008, 2009, 2010 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file bits/move.h 26 * This is an internal header file, included by other library headers. 27 * Do not attempt to use it directly. @headername{utility} 28 */ 29 30 #ifndef _MOVE_H 31 #define _MOVE_H 1 32 33 #include <bits/c++config.h> 34 #include <bits/concept_check.h> 35 36 namespace std _GLIBCXX_VISIBILITY(default) 37 { 38 _GLIBCXX_BEGIN_NAMESPACE_VERSION 39 40 // Used, in C++03 mode too, by allocators, etc. 41 template<typename _Tp> 42 inline _Tp* 43 __addressof(_Tp& __r) 44 { 45 return reinterpret_cast<_Tp*> 46 (&const_cast<char&>(reinterpret_cast<const volatile char&>(__r))); 47 } 48 49 _GLIBCXX_END_NAMESPACE_VERSION 50 } // namespace 51 52 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 53 #include <type_traits> // Brings in std::declval too. 54 55 namespace std _GLIBCXX_VISIBILITY(default) 56 { 57 _GLIBCXX_BEGIN_NAMESPACE_VERSION 58 59 /// forward (as per N3143) 60 template<typename _Tp> 61 inline _Tp&& 62 forward(typename std::remove_reference<_Tp>::type& __t) 63 { return static_cast<_Tp&&>(__t); } 64 65 template<typename _Tp> 66 inline _Tp&& 67 forward(typename std::remove_reference<_Tp>::type&& __t) 68 { 69 static_assert(!std::is_lvalue_reference<_Tp>::value, "template argument" 70 " substituting _Tp is an lvalue reference type"); 71 return static_cast<_Tp&&>(__t); 72 } 73 74 /** 75 * @brief Move a value. 76 * @ingroup mutating_algorithms 77 * @param __t A thing of arbitrary type. 78 * @return Same, moved. 79 */ 80 template<typename _Tp> 81 inline typename std::remove_reference<_Tp>::type&& 82 move(_Tp&& __t) 83 { return static_cast<typename std::remove_reference<_Tp>::type&&>(__t); } 84 85 /// declval, from type_traits. 86 87 /** 88 * @brief Returns the actual address of the object or function 89 * referenced by r, even in the presence of an overloaded 90 * operator&. 91 * @param __r Reference to an object or function. 92 * @return The actual address. 93 */ 94 template<typename _Tp> 95 inline _Tp* 96 addressof(_Tp& __r) 97 { return std::__addressof(__r); } 98 99 _GLIBCXX_END_NAMESPACE_VERSION 100 } // namespace 101 102 #define _GLIBCXX_MOVE(__val) std::move(__val) 103 #define _GLIBCXX_FORWARD(_Tp, __val) std::forward<_Tp>(__val) 104 #else 105 #define _GLIBCXX_MOVE(__val) (__val) 106 #define _GLIBCXX_FORWARD(_Tp, __val) (__val) 107 #endif 108 109 namespace std _GLIBCXX_VISIBILITY(default) 110 { 111 _GLIBCXX_BEGIN_NAMESPACE_VERSION 112 113 /** 114 * @brief Swaps two values. 115 * @ingroup mutating_algorithms 116 * @param __a A thing of arbitrary type. 117 * @param __b Another thing of arbitrary type. 118 * @return Nothing. 119 */ 120 template<typename _Tp> 121 inline void 122 swap(_Tp& __a, _Tp& __b) 123 { 124 // concept requirements 125 __glibcxx_function_requires(_SGIAssignableConcept<_Tp>) 126 127 _Tp __tmp = _GLIBCXX_MOVE(__a); 128 __a = _GLIBCXX_MOVE(__b); 129 __b = _GLIBCXX_MOVE(__tmp); 130 } 131 132 // _GLIBCXX_RESOLVE_LIB_DEFECTS 133 // DR 809. std::swap should be overloaded for array types. 134 template<typename _Tp, size_t _Nm> 135 inline void 136 swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm]) 137 { 138 for (size_t __n = 0; __n < _Nm; ++__n) 139 swap(__a[__n], __b[__n]); 140 } 141 142 _GLIBCXX_END_NAMESPACE_VERSION 143 } // namespace 144 145 #endif /* _MOVE_H */ 146
