1// <experimental/memory> -*- C++ -*-
2
3// Copyright (C) 2015-2021 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 experimental/memory
26 * This is a TS C++ Library header.
27 * @ingroup libfund-ts
28 */
29
30//
31// N4336 Working Draft, C++ Extensions for Library Fundamentals, Version 2
32//
33
34#ifndef _GLIBCXX_EXPERIMENTAL_MEMORY
35#define _GLIBCXX_EXPERIMENTAL_MEMORY 1
36
37#pragma GCC system_header
38
39#if __cplusplus >= 201402L
40
41#include <memory>
42#include <type_traits>
43#include <utility>
44#include <experimental/bits/shared_ptr.h>
45#include <bits/functional_hash.h>
46
47namespace std _GLIBCXX_VISIBILITY(default)
48{
49_GLIBCXX_BEGIN_NAMESPACE_VERSION
50
51namespace experimental
52{
53inline namespace fundamentals_v2
54{
55#define __cpp_lib_experimental_observer_ptr 201411
56
57 template <typename _Tp>
58 class observer_ptr
59 {
60 public:
61 // publish our template parameter and variations thereof
62 using element_type = _Tp;
63 using __pointer = add_pointer_t<_Tp>; // exposition-only
64 using __reference = add_lvalue_reference_t<_Tp>; // exposition-only
65
66 // 3.2.2, observer_ptr constructors
67 // default c'tor
68 constexpr observer_ptr() noexcept
69 : __t()
70 { }
71
72 // pointer-accepting c'tors
73 constexpr observer_ptr(nullptr_t) noexcept
74 : __t()
75 { }
76
77 constexpr explicit observer_ptr(__pointer __p) noexcept
78 : __t(__p)
79 { }
80
81 // copying c'tors (in addition to compiler-generated copy c'tor)
82 template <typename _Up,
83 typename = typename enable_if<
84 is_convertible<typename add_pointer<_Up>::type, __pointer
85 >::value
86 >::type>
87 constexpr observer_ptr(observer_ptr<_Up> __p) noexcept
88 : __t(__p.get())
89 {
90 }
91
92 // 3.2.3, observer_ptr observers
93 constexpr __pointer
94 get() const noexcept
95 {
96 return __t;
97 }
98
99 constexpr __reference
100 operator*() const
101 {
102 return *get();
103 }
104
105 constexpr __pointer
106 operator->() const noexcept
107 {
108 return get();
109 }
110
111 constexpr explicit operator bool() const noexcept
112 {
113 return get() != nullptr;
114 }
115
116 // 3.2.4, observer_ptr conversions
117 constexpr explicit operator __pointer() const noexcept
118 {
119 return get();
120 }
121
122 // 3.2.5, observer_ptr modifiers
123 constexpr __pointer
124 release() noexcept
125 {
126 __pointer __tmp = get();
127 reset();
128 return __tmp;
129 }
130
131 constexpr void
132 reset(__pointer __p = nullptr) noexcept
133 {
134 __t = __p;
135 }
136
137 constexpr void
138 swap(observer_ptr& __p) noexcept
139 {
140 std::swap(__t, __p.__t);
141 }
142
143 private:
144 __pointer __t;
145 }; // observer_ptr<>
146
147 template<typename _Tp>
148 void
149 swap(observer_ptr<_Tp>& __p1, observer_ptr<_Tp>& __p2) noexcept
150 {
151 __p1.swap(__p2);
152 }
153
154 template<typename _Tp>
155 observer_ptr<_Tp>
156 make_observer(_Tp* __p) noexcept
157 {
158 return observer_ptr<_Tp>(__p);
159 }
160
161 template<typename _Tp, typename _Up>
162 bool
163 operator==(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
164 {
165 return __p1.get() == __p2.get();
166 }
167
168 template<typename _Tp, typename _Up>
169 bool
170 operator!=(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
171 {
172 return !(__p1 == __p2);
173 }
174
175 template<typename _Tp>
176 bool
177 operator==(observer_ptr<_Tp> __p, nullptr_t) noexcept
178 {
179 return !__p;
180 }
181
182 template<typename _Tp>
183 bool
184 operator==(nullptr_t, observer_ptr<_Tp> __p) noexcept
185 {
186 return !__p;
187 }
188
189 template<typename _Tp>
190 bool
191 operator!=(observer_ptr<_Tp> __p, nullptr_t) noexcept
192 {
193 return bool(__p);
194 }
195
196 template<typename _Tp>
197 bool
198 operator!=(nullptr_t, observer_ptr<_Tp> __p) noexcept
199 {
200 return bool(__p);
201 }
202
203 template<typename _Tp, typename _Up>
204 bool
205 operator<(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
206 {
207 return std::less<typename common_type<typename add_pointer<_Tp>::type,
208 typename add_pointer<_Up>::type
209 >::type
210 >{}(__p1.get(), __p2.get());
211 }
212
213 template<typename _Tp, typename _Up>
214 bool
215 operator>(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
216 {
217 return __p2 < __p1;
218 }
219
220 template<typename _Tp, typename _Up>
221 bool
222 operator<=(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
223 {
224 return !(__p2 < __p1);
225 }
226
227 template<typename _Tp, typename _Up>
228 bool
229 operator>=(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
230 {
231 return !(__p1 < __p2);
232 }
233} // namespace fundamentals_v2
234} // namespace experimental
235
236template <typename _Tp>
237 struct hash<experimental::observer_ptr<_Tp>>
238 {
239 using result_type = size_t;
240 using argument_type = experimental::observer_ptr<_Tp>;
241
242 size_t
243 operator()(const experimental::observer_ptr<_Tp>& __t) const
244 noexcept(noexcept(hash<typename add_pointer<_Tp>::type> {}(__t.get())))
245 {
246 return hash<typename add_pointer<_Tp>::type> {}(__t.get());
247 }
248 };
249
250
251_GLIBCXX_END_NAMESPACE_VERSION
252} // namespace std
253
254#endif // __cplusplus <= 201103L
255
256#endif // _GLIBCXX_EXPERIMENTAL_MEMORY
257

source code of include/c++/11/experimental/memory