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4f5f9962 | 1 | // Move, forward and identity for C++11 + swap -*- C++ -*- |
1476e59c | 2 | |
a5544970 | 3 | // Copyright (C) 2007-2019 Free Software Foundation, Inc. |
1476e59c PC |
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 | |
748086b7 | 8 | // Free Software Foundation; either version 3, or (at your option) |
1476e59c PC |
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 | ||
748086b7 JJ |
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/>. | |
1476e59c | 24 | |
f910786b | 25 | /** @file bits/move.h |
1476e59c | 26 | * This is an internal header file, included by other library headers. |
f910786b | 27 | * Do not attempt to use it directly. @headername{utility} |
1476e59c PC |
28 | */ |
29 | ||
caa8b3c6 PC |
30 | #ifndef _MOVE_H |
31 | #define _MOVE_H 1 | |
1476e59c | 32 | |
e14e932b PC |
33 | #include <bits/c++config.h> |
34 | #include <bits/concept_check.h> | |
35 | ||
12ffa228 BK |
36 | namespace std _GLIBCXX_VISIBILITY(default) |
37 | { | |
38 | _GLIBCXX_BEGIN_NAMESPACE_VERSION | |
882b3d5c PC |
39 | |
40 | // Used, in C++03 mode too, by allocators, etc. | |
13901e4b JW |
41 | /** |
42 | * @brief Same as C++11 std::addressof | |
43 | * @ingroup utilities | |
44 | */ | |
882b3d5c | 45 | template<typename _Tp> |
9e023e33 | 46 | inline _GLIBCXX_CONSTEXPR _Tp* |
5d861bf2 | 47 | __addressof(_Tp& __r) _GLIBCXX_NOEXCEPT |
9e023e33 | 48 | { return __builtin_addressof(__r); } |
882b3d5c | 49 | |
4a15d842 FD |
50 | #if __cplusplus >= 201103L |
51 | ||
12ffa228 BK |
52 | _GLIBCXX_END_NAMESPACE_VERSION |
53 | } // namespace | |
882b3d5c | 54 | |
7274deff | 55 | #include <type_traits> // Brings in std::declval too. |
1476e59c | 56 | |
12ffa228 BK |
57 | namespace std _GLIBCXX_VISIBILITY(default) |
58 | { | |
59 | _GLIBCXX_BEGIN_NAMESPACE_VERSION | |
13901e4b JW |
60 | |
61 | /** | |
62 | * @addtogroup utilities | |
63 | * @{ | |
64 | */ | |
65 | ||
13901e4b JW |
66 | /** |
67 | * @brief Forward an lvalue. | |
68 | * @return The parameter cast to the specified type. | |
69 | * | |
70 | * This function is used to implement "perfect forwarding". | |
71 | */ | |
4c7aaebf | 72 | template<typename _Tp> |
a4eeb822 | 73 | constexpr _Tp&& |
5d861bf2 | 74 | forward(typename std::remove_reference<_Tp>::type& __t) noexcept |
4c7aaebf PC |
75 | { return static_cast<_Tp&&>(__t); } |
76 | ||
13901e4b JW |
77 | /** |
78 | * @brief Forward an rvalue. | |
79 | * @return The parameter cast to the specified type. | |
80 | * | |
81 | * This function is used to implement "perfect forwarding". | |
82 | */ | |
4c7aaebf | 83 | template<typename _Tp> |
a4eeb822 | 84 | constexpr _Tp&& |
5d861bf2 | 85 | forward(typename std::remove_reference<_Tp>::type&& __t) noexcept |
ad269884 PC |
86 | { |
87 | static_assert(!std::is_lvalue_reference<_Tp>::value, "template argument" | |
88 | " substituting _Tp is an lvalue reference type"); | |
89 | return static_cast<_Tp&&>(__t); | |
90 | } | |
e7f1930f | 91 | |
fd9380a6 | 92 | /** |
13901e4b | 93 | * @brief Convert a value to an rvalue. |
fd9380a6 | 94 | * @param __t A thing of arbitrary type. |
13901e4b | 95 | * @return The parameter cast to an rvalue-reference to allow moving it. |
fd9380a6 | 96 | */ |
1476e59c | 97 | template<typename _Tp> |
a4eeb822 | 98 | constexpr typename std::remove_reference<_Tp>::type&& |
5d861bf2 | 99 | move(_Tp&& __t) noexcept |
e7f1930f | 100 | { return static_cast<typename std::remove_reference<_Tp>::type&&>(__t); } |
1476e59c | 101 | |
74a2a1b4 PC |
102 | |
103 | template<typename _Tp> | |
104 | struct __move_if_noexcept_cond | |
105 | : public __and_<__not_<is_nothrow_move_constructible<_Tp>>, | |
106 | is_copy_constructible<_Tp>>::type { }; | |
107 | ||
1f428429 | 108 | /** |
13901e4b | 109 | * @brief Conditionally convert a value to an rvalue. |
1f428429 | 110 | * @param __x A thing of arbitrary type. |
13901e4b JW |
111 | * @return The parameter, possibly cast to an rvalue-reference. |
112 | * | |
113 | * Same as std::move unless the type's move constructor could throw and the | |
114 | * type is copyable, in which case an lvalue-reference is returned instead. | |
1f428429 PC |
115 | */ |
116 | template<typename _Tp> | |
fa409833 | 117 | constexpr typename |
74a2a1b4 | 118 | conditional<__move_if_noexcept_cond<_Tp>::value, const _Tp&, _Tp&&>::type |
1f428429 PC |
119 | move_if_noexcept(_Tp& __x) noexcept |
120 | { return std::move(__x); } | |
121 | ||
13901e4b | 122 | // declval, from type_traits. |
7274deff | 123 | |
9e023e33 JW |
124 | #if __cplusplus > 201402L |
125 | // _GLIBCXX_RESOLVE_LIB_DEFECTS | |
126 | // 2296. std::addressof should be constexpr | |
127 | # define __cpp_lib_addressof_constexpr 201603 | |
128 | #endif | |
882b3d5c PC |
129 | /** |
130 | * @brief Returns the actual address of the object or function | |
131 | * referenced by r, even in the presence of an overloaded | |
132 | * operator&. | |
133 | * @param __r Reference to an object or function. | |
134 | * @return The actual address. | |
135 | */ | |
136 | template<typename _Tp> | |
9e023e33 | 137 | inline _GLIBCXX17_CONSTEXPR _Tp* |
5d861bf2 | 138 | addressof(_Tp& __r) noexcept |
882b3d5c PC |
139 | { return std::__addressof(__r); } |
140 | ||
3ce96851 JW |
141 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
142 | // 2598. addressof works on temporaries | |
143 | template<typename _Tp> | |
144 | const _Tp* addressof(const _Tp&&) = delete; | |
145 | ||
9b817548 JW |
146 | // C++11 version of std::exchange for internal use. |
147 | template <typename _Tp, typename _Up = _Tp> | |
148 | inline _Tp | |
149 | __exchange(_Tp& __obj, _Up&& __new_val) | |
150 | { | |
151 | _Tp __old_val = std::move(__obj); | |
152 | __obj = std::forward<_Up>(__new_val); | |
153 | return __old_val; | |
154 | } | |
155 | ||
13901e4b | 156 | /// @} group utilities |
1476e59c | 157 | |
5f1fd346 | 158 | #define _GLIBCXX_MOVE(__val) std::move(__val) |
55dd8445 | 159 | #define _GLIBCXX_FORWARD(_Tp, __val) std::forward<_Tp>(__val) |
d98f312c | 160 | #else |
5f1fd346 | 161 | #define _GLIBCXX_MOVE(__val) (__val) |
55dd8445 | 162 | #define _GLIBCXX_FORWARD(_Tp, __val) (__val) |
1476e59c PC |
163 | #endif |
164 | ||
13901e4b JW |
165 | /** |
166 | * @addtogroup utilities | |
167 | * @{ | |
168 | */ | |
169 | ||
e14e932b PC |
170 | /** |
171 | * @brief Swaps two values. | |
fd9380a6 BK |
172 | * @param __a A thing of arbitrary type. |
173 | * @param __b Another thing of arbitrary type. | |
e14e932b PC |
174 | * @return Nothing. |
175 | */ | |
176 | template<typename _Tp> | |
ddb63209 | 177 | inline |
734f5023 | 178 | #if __cplusplus >= 201103L |
a2863bde VV |
179 | typename enable_if<__and_<__not_<__is_tuple_like<_Tp>>, |
180 | is_move_constructible<_Tp>, | |
ddb63209 VV |
181 | is_move_assignable<_Tp>>::value>::type |
182 | swap(_Tp& __a, _Tp& __b) | |
6f59ea25 PC |
183 | noexcept(__and_<is_nothrow_move_constructible<_Tp>, |
184 | is_nothrow_move_assignable<_Tp>>::value) | |
ddb63209 VV |
185 | #else |
186 | void | |
187 | swap(_Tp& __a, _Tp& __b) | |
173f26ae | 188 | #endif |
e14e932b PC |
189 | { |
190 | // concept requirements | |
191 | __glibcxx_function_requires(_SGIAssignableConcept<_Tp>) | |
192 | ||
193 | _Tp __tmp = _GLIBCXX_MOVE(__a); | |
194 | __a = _GLIBCXX_MOVE(__b); | |
195 | __b = _GLIBCXX_MOVE(__tmp); | |
196 | } | |
197 | ||
caa8b3c6 PC |
198 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
199 | // DR 809. std::swap should be overloaded for array types. | |
13901e4b | 200 | /// Swap the contents of two arrays. |
caa8b3c6 | 201 | template<typename _Tp, size_t _Nm> |
ddb63209 | 202 | inline |
734f5023 | 203 | #if __cplusplus >= 201103L |
26b5ace7 | 204 | typename enable_if<__is_swappable<_Tp>::value>::type |
ddb63209 | 205 | swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm]) |
26b5ace7 | 206 | noexcept(__is_nothrow_swappable<_Tp>::value) |
ddb63209 VV |
207 | #else |
208 | void | |
209 | swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm]) | |
ccb4f5a7 | 210 | #endif |
caa8b3c6 PC |
211 | { |
212 | for (size_t __n = 0; __n < _Nm; ++__n) | |
213 | swap(__a[__n], __b[__n]); | |
214 | } | |
215 | ||
13901e4b | 216 | /// @} group utilities |
12ffa228 BK |
217 | _GLIBCXX_END_NAMESPACE_VERSION |
218 | } // namespace | |
e14e932b | 219 | |
caa8b3c6 | 220 | #endif /* _MOVE_H */ |