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 57 namespace 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