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The C and C++ Include Header Files
/usr/include/c++/13/bits/allocator.h
$ cat -n /usr/include/c++/13/bits/allocator.h 1 // Allocators -*- C++ -*- 2 3 // Copyright (C) 2001-2023 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 201505L 53 54 namespace std _GLIBCXX_VISIBILITY(default) 55 { 56 _GLIBCXX_BEGIN_NAMESPACE_VERSION 57 58 /** 59 * @addtogroup allocators 60 * @{ 61 */ 62 63 // Since C++20 the primary template should be used for allocator<void>, 64 // but then it would have a non-trivial default ctor and dtor for C++20, 65 // but trivial for C++98-17, which would be an ABI incompatibility between 66 // different standard dialects. So C++20 still uses the allocator<void> 67 // explicit specialization, with the historical ABI properties, but with 68 // the same members that are present in the primary template. 69 70 /** std::allocator<void> specialization. 71 * 72 * @headerfile memory 73 */ 74 template<> 75 class allocator<void> 76 { 77 public: 78 typedef void value_type; 79 typedef size_t size_type; 80 typedef ptrdiff_t difference_type; 81 82 #if __cplusplus <= 201703L 83 // These were removed for C++20, allocator_traits does the right thing. 84 typedef void* pointer; 85 typedef const void* const_pointer; 86 87 template<typename _Tp1> 88 struct rebind 89 { typedef allocator<_Tp1> other; }; 90 #endif 91 92 #if __cplusplus >= 201103L 93 // _GLIBCXX_RESOLVE_LIB_DEFECTS 94 // 2103. std::allocator propagate_on_container_move_assignment 95 using propagate_on_container_move_assignment = true_type; 96 97 using is_always_equal 98 _GLIBCXX20_DEPRECATED_SUGGEST("std::allocator_traits::is_always_equal") 99 = true_type; 100 101 #if __cplusplus >= 202002L 102 // As noted above, these members are present for C++20 to provide the 103 // same API as the primary template, but still trivial as in pre-C++20. 104 allocator() = default; 105 ~allocator() = default; 106 107 template<typename _Up> 108 __attribute__((__always_inline__)) 109 constexpr 110 allocator(const allocator<_Up>&) noexcept { } 111 112 // No allocate member because it's ill-formed by LWG 3307. 113 // No deallocate member because it would be undefined to call it 114 // with any pointer which wasn't obtained from allocate. 115 #endif // C++20 116 #endif // C++11 117 }; 118 119 /** 120 * @brief The @a standard allocator, as per C++03 [20.4.1]. 121 * 122 * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/memory.html#std.util.memory.allocator 123 * for further details. 124 * 125 * @tparam _Tp Type of allocated object. 126 * 127 * @headerfile memory 128 */ 129 template<typename _Tp> 130 class allocator : public __allocator_base<_Tp> 131 { 132 public: 133 typedef _Tp value_type; 134 typedef size_t size_type; 135 typedef ptrdiff_t difference_type; 136 137 #if __cplusplus <= 201703L 138 // These were removed for C++20. 139 typedef _Tp* pointer; 140 typedef const _Tp* const_pointer; 141 typedef _Tp& reference; 142 typedef const _Tp& const_reference; 143 144 template<typename _Tp1> 145 struct rebind 146 { typedef allocator<_Tp1> other; }; 147 #endif 148 149 #if __cplusplus >= 201103L 150 // _GLIBCXX_RESOLVE_LIB_DEFECTS 151 // 2103. std::allocator propagate_on_container_move_assignment 152 using propagate_on_container_move_assignment = true_type; 153 154 using is_always_equal 155 _GLIBCXX20_DEPRECATED_SUGGEST("std::allocator_traits::is_always_equal") 156 = true_type; 157 #endif 158 159 // _GLIBCXX_RESOLVE_LIB_DEFECTS 160 // 3035. std::allocator's constructors should be constexpr 161 __attribute__((__always_inline__)) 162 _GLIBCXX20_CONSTEXPR 163 allocator() _GLIBCXX_NOTHROW { } 164 165 __attribute__((__always_inline__)) 166 _GLIBCXX20_CONSTEXPR 167 allocator(const allocator& __a) _GLIBCXX_NOTHROW 168 : __allocator_base<_Tp>(__a) { } 169 170 #if __cplusplus >= 201103L 171 // Avoid implicit deprecation. 172 allocator& operator=(const allocator&) = default; 173 #endif 174 175 template<typename _Tp1> 176 __attribute__((__always_inline__)) 177 _GLIBCXX20_CONSTEXPR 178 allocator(const allocator<_Tp1>&) _GLIBCXX_NOTHROW { } 179 180 __attribute__((__always_inline__)) 181 #if __cpp_constexpr_dynamic_alloc 182 constexpr 183 #endif 184 ~allocator() _GLIBCXX_NOTHROW { } 185 186 #if __cplusplus > 201703L 187 [[nodiscard,__gnu__::__always_inline__]] 188 constexpr _Tp* 189 allocate(size_t __n) 190 { 191 if (std::__is_constant_evaluated()) 192 { 193 if (__builtin_mul_overflow(__n, sizeof(_Tp), &__n)) 194 std::__throw_bad_array_new_length(); 195 return static_cast<_Tp*>(::operator new(__n)); 196 } 197 198 return __allocator_base<_Tp>::allocate(__n, 0); 199 } 200 201 [[__gnu__::__always_inline__]] 202 constexpr void 203 deallocate(_Tp* __p, size_t __n) 204 { 205 if (std::__is_constant_evaluated()) 206 { 207 ::operator delete(__p); 208 return; 209 } 210 __allocator_base<_Tp>::deallocate(__p, __n); 211 } 212 #endif // C++20 213 214 friend __attribute__((__always_inline__)) _GLIBCXX20_CONSTEXPR 215 bool 216 operator==(const allocator&, const allocator&) _GLIBCXX_NOTHROW 217 { return true; } 218 219 #if __cpp_impl_three_way_comparison < 201907L 220 friend __attribute__((__always_inline__)) _GLIBCXX20_CONSTEXPR 221 bool 222 operator!=(const allocator&, const allocator&) _GLIBCXX_NOTHROW 223 { return false; } 224 #endif 225 226 // Inherit everything else. 227 }; 228 229 /** Equality comparison for std::allocator objects 230 * 231 * @return true, for all std::allocator objects. 232 * @relates std::allocator 233 */ 234 template<typename _T1, typename _T2> 235 __attribute__((__always_inline__)) 236 inline _GLIBCXX20_CONSTEXPR bool 237 operator==(const allocator<_T1>&, const allocator<_T2>&) 238 _GLIBCXX_NOTHROW 239 { return true; } 240 241 #if __cpp_impl_three_way_comparison < 201907L 242 template<typename _T1, typename _T2> 243 __attribute__((__always_inline__)) 244 inline _GLIBCXX20_CONSTEXPR bool 245 operator!=(const allocator<_T1>&, const allocator<_T2>&) 246 _GLIBCXX_NOTHROW 247 { return false; } 248 #endif 249 250 /// @cond undocumented 251 252 // Invalid allocator<cv T> partial specializations. 253 // allocator_traits::rebind_alloc can be used to form a valid allocator type. 254 template<typename _Tp> 255 class allocator<const _Tp> 256 { 257 public: 258 typedef _Tp value_type; 259 allocator() { } 260 template<typename _Up> allocator(const allocator<_Up>&) { } 261 }; 262 263 template<typename _Tp> 264 class allocator<volatile _Tp> 265 { 266 public: 267 typedef _Tp value_type; 268 allocator() { } 269 template<typename _Up> allocator(const allocator<_Up>&) { } 270 }; 271 272 template<typename _Tp> 273 class allocator<const volatile _Tp> 274 { 275 public: 276 typedef _Tp value_type; 277 allocator() { } 278 template<typename _Up> allocator(const allocator<_Up>&) { } 279 }; 280 /// @endcond 281 282 /// @} group allocator 283 284 // Inhibit implicit instantiations for required instantiations, 285 // which are defined via explicit instantiations elsewhere. 286 #if _GLIBCXX_EXTERN_TEMPLATE 287 extern template class allocator<char>; 288 extern template class allocator<wchar_t>; 289 #endif 290 291 // Undefine. 292 #undef __allocator_base 293 294 _GLIBCXX_END_NAMESPACE_VERSION 295 } // namespace std 296 297 #endif
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