1// <experimental/memory_resource> -*- C++ -*- 2 3// Copyright (C) 2015-2018 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_resource 26 * This is a TS C++ Library header. 27 */ 28 29#ifndef _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE 30#define _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE 1 31 32#include <memory> 33#include <new> 34#include <atomic> 35#include <cstddef> 36#include <bits/alloc_traits.h> 37#include <experimental/bits/lfts_config.h> 38 39namespace std { 40_GLIBCXX_BEGIN_NAMESPACE_VERSION 41 42namespace experimental { 43inline namespace fundamentals_v2 { 44namespace pmr { 45#define __cpp_lib_experimental_memory_resources 201402L 46 47 class memory_resource; 48 49 template <typename _Tp> 50 class polymorphic_allocator; 51 52 template <typename _Alloc> 53 class __resource_adaptor_imp; 54 55 template <typename _Alloc> 56 using resource_adaptor = __resource_adaptor_imp< 57 typename allocator_traits<_Alloc>::template rebind_alloc<char>>; 58 59 template <typename _Tp> 60 struct __uses_allocator_construction_helper; 61 62 // Global memory resources 63 memory_resource* new_delete_resource() noexcept; 64 memory_resource* null_memory_resource() noexcept; 65 66 // The default memory resource 67 memory_resource* get_default_resource() noexcept; 68 memory_resource* set_default_resource(memory_resource* __r) noexcept; 69 70 // Standard memory resources 71 72 // 8.5 Class memory_resource 73 class memory_resource 74 { 75 protected: 76 static constexpr size_t _S_max_align = alignof(max_align_t); 77 78 public: 79 virtual ~memory_resource() { } 80 81 void* 82 allocate(size_t __bytes, size_t __alignment = _S_max_align) 83 { return do_allocate(__bytes, __alignment); } 84 85 void 86 deallocate(void* __p, size_t __bytes, size_t __alignment = _S_max_align) 87 { return do_deallocate(__p, __bytes, __alignment); } 88 89 bool 90 is_equal(const memory_resource& __other) const noexcept 91 { return do_is_equal(__other); } 92 93 protected: 94 virtual void* 95 do_allocate(size_t __bytes, size_t __alignment) = 0; 96 97 virtual void 98 do_deallocate(void* __p, size_t __bytes, size_t __alignment) = 0; 99 100 virtual bool 101 do_is_equal(const memory_resource& __other) const noexcept = 0; 102 }; 103 104 inline bool 105 operator==(const memory_resource& __a, 106 const memory_resource& __b) noexcept 107 { return &__a == &__b || __a.is_equal(__b); } 108 109 inline bool 110 operator!=(const memory_resource& __a, 111 const memory_resource& __b) noexcept 112 { return !(__a == __b); } 113 114 115 // 8.6 Class template polymorphic_allocator 116 template <class _Tp> 117 class polymorphic_allocator 118 { 119 using __uses_alloc1_ = __uses_alloc1<memory_resource*>; 120 using __uses_alloc2_ = __uses_alloc2<memory_resource*>; 121 122 template<typename _Tp1, typename... _Args> 123 void 124 _M_construct(__uses_alloc0, _Tp1* __p, _Args&&... __args) 125 { ::new(__p) _Tp1(std::forward<_Args>(__args)...); } 126 127 template<typename _Tp1, typename... _Args> 128 void 129 _M_construct(__uses_alloc1_, _Tp1* __p, _Args&&... __args) 130 { ::new(__p) _Tp1(allocator_arg, this->resource(), 131 std::forward<_Args>(__args)...); } 132 133 template<typename _Tp1, typename... _Args> 134 void 135 _M_construct(__uses_alloc2_, _Tp1* __p, _Args&&... __args) 136 { ::new(__p) _Tp1(std::forward<_Args>(__args)..., 137 this->resource()); } 138 139 public: 140 using value_type = _Tp; 141 142 polymorphic_allocator() noexcept 143 : _M_resource(get_default_resource()) 144 { } 145 146 polymorphic_allocator(memory_resource* __r) 147 : _M_resource(__r) 148 { _GLIBCXX_DEBUG_ASSERT(__r); } 149 150 polymorphic_allocator(const polymorphic_allocator& __other) = default; 151 152 template <typename _Up> 153 polymorphic_allocator(const polymorphic_allocator<_Up>& 154 __other) noexcept 155 : _M_resource(__other.resource()) 156 { } 157 158 polymorphic_allocator& 159 operator=(const polymorphic_allocator& __rhs) = default; 160 161 _Tp* allocate(size_t __n) 162 { return static_cast<_Tp*>(_M_resource->allocate(__n * sizeof(_Tp), 163 alignof(_Tp))); } 164 165 void deallocate(_Tp* __p, size_t __n) 166 { _M_resource->deallocate(__p, __n * sizeof(_Tp), alignof(_Tp)); } 167 168 template <typename _Tp1, typename... _Args> //used here 169 void construct(_Tp1* __p, _Args&&... __args) 170 { 171 memory_resource* const __resource = this->resource(); 172 auto __use_tag 173 = __use_alloc<_Tp1, memory_resource*, _Args...>(__resource); 174 _M_construct(__use_tag, __p, std::forward<_Args>(__args)...); 175 } 176 177 // Specializations for pair using piecewise construction 178 template <typename _Tp1, typename _Tp2, 179 typename... _Args1, typename... _Args2> 180 void construct(pair<_Tp1, _Tp2>* __p, piecewise_construct_t, 181 tuple<_Args1...> __x, 182 tuple<_Args2...> __y) 183 { 184 memory_resource* const __resource = this->resource(); 185 auto __x_use_tag = 186 __use_alloc<_Tp1, memory_resource*, _Args1...>(__resource); 187 auto __y_use_tag = 188 __use_alloc<_Tp2, memory_resource*, _Args2...>(__resource); 189 190 ::new(__p) std::pair<_Tp1, _Tp2>(piecewise_construct, 191 _M_construct_p(__x_use_tag, __x), 192 _M_construct_p(__y_use_tag, __y)); 193 } 194 195 template <typename _Tp1, typename _Tp2> 196 void construct(pair<_Tp1,_Tp2>* __p) 197 { this->construct(__p, piecewise_construct, tuple<>(), tuple<>()); } 198 199 template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp> 200 void construct(pair<_Tp1,_Tp2>* __p, _Up&& __x, _Vp&& __y) 201 { this->construct(__p, piecewise_construct, 202 forward_as_tuple(std::forward<_Up>(__x)), 203 forward_as_tuple(std::forward<_Vp>(__y))); } 204 205 template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp> 206 void construct(pair<_Tp1,_Tp2>* __p, const std::pair<_Up, _Vp>& __pr) 207 { this->construct(__p, piecewise_construct, forward_as_tuple(__pr.first), 208 forward_as_tuple(__pr.second)); } 209 210 template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp> 211 void construct(pair<_Tp1,_Tp2>* __p, pair<_Up, _Vp>&& __pr) 212 { this->construct(__p, piecewise_construct, 213 forward_as_tuple(std::forward<_Up>(__pr.first)), 214 forward_as_tuple(std::forward<_Vp>(__pr.second))); } 215 216 template <typename _Up> 217 void destroy(_Up* __p) 218 { __p->~_Up(); } 219 220 // Return a default-constructed allocator (no allocator propagation) 221 polymorphic_allocator select_on_container_copy_construction() const 222 { return polymorphic_allocator(); } 223 224 memory_resource* resource() const 225 { return _M_resource; } 226 227 private: 228 template<typename _Tuple> 229 _Tuple&& 230 _M_construct_p(__uses_alloc0, _Tuple& __t) 231 { return std::move(__t); } 232 233 template<typename... _Args> 234 decltype(auto) 235 _M_construct_p(__uses_alloc1_ __ua, tuple<_Args...>& __t) 236 { return tuple_cat(make_tuple(allocator_arg, *(__ua._M_a)), 237 std::move(__t)); } 238 239 template<typename... _Args> 240 decltype(auto) 241 _M_construct_p(__uses_alloc2_ __ua, tuple<_Args...>& __t) 242 { return tuple_cat(std::move(__t), make_tuple(*(__ua._M_a))); } 243 244 memory_resource* _M_resource; 245 }; 246 247 template <class _Tp1, class _Tp2> 248 bool operator==(const polymorphic_allocator<_Tp1>& __a, 249 const polymorphic_allocator<_Tp2>& __b) noexcept 250 { return *__a.resource() == *__b.resource(); } 251 252 template <class _Tp1, class _Tp2> 253 bool operator!=(const polymorphic_allocator<_Tp1>& __a, 254 const polymorphic_allocator<_Tp2>& __b) noexcept 255 { return !(__a == __b); } 256 257 // 8.7.1 __resource_adaptor_imp 258 template <typename _Alloc> 259 class __resource_adaptor_imp : public memory_resource 260 { 261 public: 262 using allocator_type = _Alloc; 263 264 __resource_adaptor_imp() = default; 265 __resource_adaptor_imp(const __resource_adaptor_imp&) = default; 266 __resource_adaptor_imp(__resource_adaptor_imp&&) = default; 267 268 explicit __resource_adaptor_imp(const _Alloc& __a2) 269 : _M_alloc(__a2) 270 { } 271 272 explicit __resource_adaptor_imp(_Alloc&& __a2) 273 : _M_alloc(std::move(__a2)) 274 { } 275 276 __resource_adaptor_imp& 277 operator=(const __resource_adaptor_imp&) = default; 278 279 allocator_type get_allocator() const { return _M_alloc; } 280 281 protected: 282 virtual void* 283 do_allocate(size_t __bytes, size_t __alignment) 284 { 285 using _Aligned_alloc = std::__alloc_rebind<_Alloc, char>; 286 size_t __new_size = _S_aligned_size(__bytes, 287 _S_supported(__alignment) ? 288 __alignment : _S_max_align); 289 return _Aligned_alloc(_M_alloc).allocate(__new_size); 290 } 291 292 virtual void 293 do_deallocate(void* __p, size_t __bytes, size_t __alignment) 294 { 295 using _Aligned_alloc = std::__alloc_rebind<_Alloc, char>; 296 size_t __new_size = _S_aligned_size(__bytes, 297 _S_supported(__alignment) ? 298 __alignment : _S_max_align); 299 using _Ptr = typename allocator_traits<_Aligned_alloc>::pointer; 300 _Aligned_alloc(_M_alloc).deallocate(static_cast<_Ptr>(__p), 301 __new_size); 302 } 303 304 virtual bool 305 do_is_equal(const memory_resource& __other) const noexcept 306 { 307 auto __p = dynamic_cast<const __resource_adaptor_imp*>(&__other); 308 return __p ? (_M_alloc == __p->_M_alloc) : false; 309 } 310 311 private: 312 // Calculate Aligned Size 313 // Returns a size that is larger than or equal to __size and divisible 314 // by __alignment, where __alignment is required to be the power of 2. 315 static size_t 316 _S_aligned_size(size_t __size, size_t __alignment) 317 { return ((__size - 1)|(__alignment - 1)) + 1; } 318 319 // Determine whether alignment meets one of those preconditions: 320 // 1. Equals to Zero 321 // 2. Is power of two 322 static bool 323 _S_supported (size_t __x) 324 { return ((__x != 0) && !(__x & (__x - 1))); } 325 326 _Alloc _M_alloc; 327 }; 328 329 // Global memory resources 330 inline std::atomic<memory_resource*>& 331 __get_default_resource() 332 { 333 static atomic<memory_resource*> _S_default_resource(new_delete_resource()); 334 return _S_default_resource; 335 } 336 337 inline memory_resource* 338 new_delete_resource() noexcept 339 { 340 static resource_adaptor<std::allocator<char>> __r; 341 return static_cast<memory_resource*>(&__r); 342 } 343 344 template <typename _Alloc> 345 class __null_memory_resource : private memory_resource 346 { 347 protected: 348 void* 349 do_allocate(size_t, size_t) 350 { std::__throw_bad_alloc(); } 351 352 void 353 do_deallocate(void*, size_t, size_t) noexcept 354 { } 355 356 bool 357 do_is_equal(const memory_resource& __other) const noexcept 358 { return this == &__other; } 359 360 friend memory_resource* null_memory_resource() noexcept; 361 }; 362 363 inline memory_resource* 364 null_memory_resource() noexcept 365 { 366 static __null_memory_resource<void> __r; 367 return static_cast<memory_resource*>(&__r); 368 } 369 370 // The default memory resource 371 inline memory_resource* 372 get_default_resource() noexcept 373 { return __get_default_resource().load(); } 374 375 inline memory_resource* 376 set_default_resource(memory_resource* __r) noexcept 377 { 378 if (__r == nullptr) 379 __r = new_delete_resource(); 380 return __get_default_resource().exchange(__r); 381 } 382} // namespace pmr 383} // namespace fundamentals_v2 384} // namespace experimental 385 386_GLIBCXX_END_NAMESPACE_VERSION 387} // namespace std 388 389#endif 390