1 | // Move, forward and identity for C++0x + swap -*- C++ -*- |
2 | |
3 | // Copyright (C) 2007-2014 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 | /** |
42 | * @brief Same as C++11 std::addressof |
43 | * @ingroup utilities |
44 | */ |
45 | template<typename _Tp> |
46 | inline _Tp* |
47 | __addressof(_Tp& __r) _GLIBCXX_NOEXCEPT |
48 | { |
49 | return reinterpret_cast<_Tp*> |
50 | (&const_cast<char&>(reinterpret_cast<const volatile char&>(__r))); |
51 | } |
52 | |
53 | _GLIBCXX_END_NAMESPACE_VERSION |
54 | } // namespace |
55 | |
56 | #if __cplusplus >= 201103L |
57 | #include <type_traits> // Brings in std::declval too. |
58 | |
59 | namespace std _GLIBCXX_VISIBILITY(default) |
60 | { |
61 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
62 | |
63 | /** |
64 | * @addtogroup utilities |
65 | * @{ |
66 | */ |
67 | |
68 | /** |
69 | * @brief Forward an lvalue. |
70 | * @return The parameter cast to the specified type. |
71 | * |
72 | * This function is used to implement "perfect forwarding". |
73 | */ |
74 | template<typename _Tp> |
75 | constexpr _Tp&& |
76 | forward(typename std::remove_reference<_Tp>::type& __t) noexcept |
77 | { return static_cast<_Tp&&>(__t); } |
78 | |
79 | /** |
80 | * @brief Forward an rvalue. |
81 | * @return The parameter cast to the specified type. |
82 | * |
83 | * This function is used to implement "perfect forwarding". |
84 | */ |
85 | template<typename _Tp> |
86 | constexpr _Tp&& |
87 | forward(typename std::remove_reference<_Tp>::type&& __t) noexcept |
88 | { |
89 | static_assert(!std::is_lvalue_reference<_Tp>::value, "template argument" |
90 | " substituting _Tp is an lvalue reference type" ); |
91 | return static_cast<_Tp&&>(__t); |
92 | } |
93 | |
94 | /** |
95 | * @brief Convert a value to an rvalue. |
96 | * @param __t A thing of arbitrary type. |
97 | * @return The parameter cast to an rvalue-reference to allow moving it. |
98 | */ |
99 | template<typename _Tp> |
100 | constexpr typename std::remove_reference<_Tp>::type&& |
101 | move(_Tp&& __t) noexcept |
102 | { return static_cast<typename std::remove_reference<_Tp>::type&&>(__t); } |
103 | |
104 | |
105 | template<typename _Tp> |
106 | struct __move_if_noexcept_cond |
107 | : public __and_<__not_<is_nothrow_move_constructible<_Tp>>, |
108 | is_copy_constructible<_Tp>>::type { }; |
109 | |
110 | /** |
111 | * @brief Conditionally convert a value to an rvalue. |
112 | * @param __x A thing of arbitrary type. |
113 | * @return The parameter, possibly cast to an rvalue-reference. |
114 | * |
115 | * Same as std::move unless the type's move constructor could throw and the |
116 | * type is copyable, in which case an lvalue-reference is returned instead. |
117 | */ |
118 | template<typename _Tp> |
119 | constexpr typename |
120 | conditional<__move_if_noexcept_cond<_Tp>::value, const _Tp&, _Tp&&>::type |
121 | move_if_noexcept(_Tp& __x) noexcept |
122 | { return std::move(__x); } |
123 | |
124 | // declval, from type_traits. |
125 | |
126 | /** |
127 | * @brief Returns the actual address of the object or function |
128 | * referenced by r, even in the presence of an overloaded |
129 | * operator&. |
130 | * @param __r Reference to an object or function. |
131 | * @return The actual address. |
132 | */ |
133 | template<typename _Tp> |
134 | inline _Tp* |
135 | addressof(_Tp& __r) noexcept |
136 | { return std::__addressof(__r); } |
137 | |
138 | /// @} group utilities |
139 | _GLIBCXX_END_NAMESPACE_VERSION |
140 | } // namespace |
141 | |
142 | #define _GLIBCXX_MOVE(__val) std::move(__val) |
143 | #define _GLIBCXX_FORWARD(_Tp, __val) std::forward<_Tp>(__val) |
144 | #else |
145 | #define _GLIBCXX_MOVE(__val) (__val) |
146 | #define _GLIBCXX_FORWARD(_Tp, __val) (__val) |
147 | #endif |
148 | |
149 | namespace std _GLIBCXX_VISIBILITY(default) |
150 | { |
151 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
152 | |
153 | /** |
154 | * @addtogroup utilities |
155 | * @{ |
156 | */ |
157 | |
158 | /** |
159 | * @brief Swaps two values. |
160 | * @param __a A thing of arbitrary type. |
161 | * @param __b Another thing of arbitrary type. |
162 | * @return Nothing. |
163 | */ |
164 | template<typename _Tp> |
165 | inline void |
166 | swap(_Tp& __a, _Tp& __b) |
167 | #if __cplusplus >= 201103L |
168 | noexcept(__and_<is_nothrow_move_constructible<_Tp>, |
169 | is_nothrow_move_assignable<_Tp>>::value) |
170 | #endif |
171 | { |
172 | // concept requirements |
173 | __glibcxx_function_requires(_SGIAssignableConcept<_Tp>) |
174 | |
175 | _Tp __tmp = _GLIBCXX_MOVE(__a); |
176 | __a = _GLIBCXX_MOVE(__b); |
177 | __b = _GLIBCXX_MOVE(__tmp); |
178 | } |
179 | |
180 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
181 | // DR 809. std::swap should be overloaded for array types. |
182 | /// Swap the contents of two arrays. |
183 | template<typename _Tp, size_t _Nm> |
184 | inline void |
185 | swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm]) |
186 | #if __cplusplus >= 201103L |
187 | noexcept(noexcept(swap(*__a, *__b))) |
188 | #endif |
189 | { |
190 | for (size_t __n = 0; __n < _Nm; ++__n) |
191 | swap(__a[__n], __b[__n]); |
192 | } |
193 | |
194 | /// @} group utilities |
195 | _GLIBCXX_END_NAMESPACE_VERSION |
196 | } // namespace |
197 | |
198 | #endif /* _MOVE_H */ |
199 | |