1// Allocators -*- C++ -*- 
2 
3// Copyright (C) 2001-2019 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/* 
26 * Copyright (c) 1996-1997 
27 * Silicon Graphics Computer Systems, Inc. 
28 * 
29 * Permission to use, copy, modify, distribute and sell this software 
30 * and its documentation for any purpose is hereby granted without fee, 
31 * provided that the above copyright notice appear in all copies and 
32 * that both that copyright notice and this permission notice appear 
33 * in supporting documentation. Silicon Graphics makes no 
34 * representations about the suitability of this software for any 
35 * purpose. It is provided "as is" without express or implied warranty. 
36 */ 
37 
38/** @file bits/allocator.h 
39 * This is an internal header file, included by other library headers. 
40 * Do not attempt to use it directly. @headername{memory} 
41 */ 
42 
43#ifndef _ALLOCATOR_H 
44#define _ALLOCATOR_H 1 
45 
46#include <bits/c++allocator.h> // Define the base class to std::allocator. 
47#include <bits/memoryfwd.h> 
48#if __cplusplus >= 201103L 
49#include <type_traits> 
50#endif 
51 
52#define __cpp_lib_incomplete_container_elements 201505 
53#if __cplusplus >= 201103L 
54# define __cpp_lib_allocator_is_always_equal 201411 
55#endif 
56 
57namespace std _GLIBCXX_VISIBILITY(default) 
58{ 
59_GLIBCXX_BEGIN_NAMESPACE_VERSION 
60 
61 /** 
62 * @addtogroup allocators 
63 * @{ 
64 */ 
65 
66 /// allocator<void> specialization. 
67 template<> 
68 class allocator<void> 
69 { 
70 public: 
71 typedef size_t size_type; 
72 typedef ptrdiff_t difference_type; 
73 typedef void* pointer; 
74 typedef const void* const_pointer; 
75 typedef void value_type; 
76 
77 template<typename _Tp1> 
78 struct rebind 
79 { typedef allocator<_Tp1> other; }; 
80 
81#if __cplusplus >= 201103L 
82 // _GLIBCXX_RESOLVE_LIB_DEFECTS 
83 // 2103. std::allocator propagate_on_container_move_assignment 
84 typedef true_type propagate_on_container_move_assignment; 
85 
86 typedef true_type is_always_equal; 
87 
88 template<typename _Up, typename... _Args> 
89 void 
90 construct(_Up* __p, _Args&&... __args) 
91 noexcept(noexcept(::new((void *)__p) 
92 _Up(std::forward<_Args>(__args)...))) 
93 { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } 
94 
95 template<typename _Up> 
96 void 
97 destroy(_Up* __p) 
98 noexcept(noexcept(__p->~_Up())) 
99 { __p->~_Up(); } 
100#endif 
101 }; 
102 
103 /** 
104 * @brief The @a standard allocator, as per [20.4]. 
105 * 
106 * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/memory.html#std.util.memory.allocator 
107 * for further details. 
108 * 
109 * @tparam _Tp Type of allocated object. 
110 */ 
111 template<typename _Tp> 
112 class allocator : public __allocator_base<_Tp> 
113 { 
114 public: 
115 typedef size_t size_type; 
116 typedef ptrdiff_t difference_type; 
117 typedef _Tp* pointer; 
118 typedef const _Tp* const_pointer; 
119 typedef _Tp& reference; 
120 typedef const _Tp& const_reference; 
121 typedef _Tp value_type; 
122 
123 template<typename _Tp1> 
124 struct rebind 
125 { typedef allocator<_Tp1> other; }; 
126 
127#if __cplusplus >= 201103L 
128 // _GLIBCXX_RESOLVE_LIB_DEFECTS 
129 // 2103. std::allocator propagate_on_container_move_assignment 
130 typedef true_type propagate_on_container_move_assignment; 
131 
132 typedef true_type is_always_equal; 
133#endif 
134 
135 // _GLIBCXX_RESOLVE_LIB_DEFECTS 
136 // 3035. std::allocator's constructors should be constexpr 
137 _GLIBCXX20_CONSTEXPR 
138 allocator() _GLIBCXX_NOTHROW { } 
139 
140 _GLIBCXX20_CONSTEXPR 
141 allocator(const allocator& __a) _GLIBCXX_NOTHROW 
142 : __allocator_base<_Tp>(__a) { } 
143 
144#if __cplusplus >= 201103L 
145 // Avoid implicit deprecation. 
146 allocator& operator=(const allocator&) = default; 
147#endif 
148 
149 template<typename _Tp1> 
150 _GLIBCXX20_CONSTEXPR 
151 allocator(const allocator<_Tp1>&) _GLIBCXX_NOTHROW { } 
152 
153 ~allocator() _GLIBCXX_NOTHROW { } 
154 
155 friend bool 
156 operator==(const allocator&, const allocator&) _GLIBCXX_NOTHROW 
157 { return true; } 
158 
159 friend bool 
160 operator!=(const allocator&, const allocator&) _GLIBCXX_NOTHROW 
161 { return false; } 
162 
163 // Inherit everything else. 
164 }; 
165 
166 template<typename _T1, typename _T2> 
167 inline bool 
168 operator==(const allocator<_T1>&, const allocator<_T2>&) 
169 _GLIBCXX_NOTHROW 
170 { return true; } 
171 
172 template<typename _T1, typename _T2> 
173 inline bool 
174 operator!=(const allocator<_T1>&, const allocator<_T2>&) 
175 _GLIBCXX_NOTHROW 
176 { return false; } 
177 
178 // Invalid allocator<cv T> partial specializations. 
179 // allocator_traits::rebind_alloc can be used to form a valid allocator type. 
180 template<typename _Tp> 
181 class allocator<const _Tp> 
182 { 
183 public: 
184 typedef _Tp value_type; 
185 template<typename _Up> allocator(const allocator<_Up>&) { } 
186 }; 
187 
188 template<typename _Tp> 
189 class allocator<volatile _Tp> 
190 { 
191 public: 
192 typedef _Tp value_type; 
193 template<typename _Up> allocator(const allocator<_Up>&) { } 
194 }; 
195 
196 template<typename _Tp> 
197 class allocator<const volatile _Tp> 
198 { 
199 public: 
200 typedef _Tp value_type; 
201 template<typename _Up> allocator(const allocator<_Up>&) { } 
202 }; 
203 
204 /// @} group allocator 
205 
206 // Inhibit implicit instantiations for required instantiations, 
207 // which are defined via explicit instantiations elsewhere. 
208#if _GLIBCXX_EXTERN_TEMPLATE 
209 extern template class allocator<char>; 
210 extern template class allocator<wchar_t>; 
211#endif 
212 
213 // Undefine. 
214#undef __allocator_base 
215 
216 // To implement Option 3 of DR 431. 
217 template<typename _Alloc, bool = __is_empty(_Alloc)> 
218 struct __alloc_swap 
219 { static void _S_do_it(_Alloc&, _Alloc&) _GLIBCXX_NOEXCEPT { } }; 
220 
221 template<typename _Alloc> 
222 struct __alloc_swap<_Alloc, false> 
223 { 
224 static void 
225 _S_do_it(_Alloc& __one, _Alloc& __two) _GLIBCXX_NOEXCEPT 
226 { 
227 // Precondition: swappable allocators. 
228 if (__one != __two) 
229 swap(__one, __two); 
230 } 
231 }; 
232 
233 // Optimize for stateless allocators. 
234 template<typename _Alloc, bool = __is_empty(_Alloc)> 
235 struct __alloc_neq 
236 { 
237 static bool 
238 _S_do_it(const _Alloc&, const _Alloc&) 
239 { return false; } 
240 }; 
241 
242 template<typename _Alloc> 
243 struct __alloc_neq<_Alloc, false> 
244 { 
245 static bool 
246 _S_do_it(const _Alloc& __one, const _Alloc& __two) 
247 { return __one != __two; } 
248 }; 
249 
250#if __cplusplus >= 201103L 
251 template<typename _Tp, bool 
252 = __or_<is_copy_constructible<typename _Tp::value_type>, 
253 is_nothrow_move_constructible<typename _Tp::value_type>>::value> 
254 struct __shrink_to_fit_aux 
255 { static bool _S_do_it(_Tp&) noexcept { return false; } }; 
256 
257 template<typename _Tp> 
258 struct __shrink_to_fit_aux<_Tp, true> 
259 { 
260 static bool 
261 _S_do_it(_Tp& __c) noexcept 
262 { 
263#if __cpp_exceptions 
264 try 
265 { 
266 _Tp(__make_move_if_noexcept_iterator(__c.begin()), 
267 __make_move_if_noexcept_iterator(__c.end()), 
268 __c.get_allocator()).swap(__c); 
269 return true; 
270 } 
271 catch(...) 
272 { return false; } 
273#else 
274 return false; 
275#endif 
276 } 
277 }; 
278#endif 
279 
280_GLIBCXX_END_NAMESPACE_VERSION 
281} // namespace std 
282 
283#endif 
284