libstdc++
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00001 // <experimental/memory_resource> -*- C++ -*- 00002 00003 // Copyright (C) 2015-2018 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file experimental/memory_resource 00026 * This is a TS C++ Library header. 00027 */ 00028 00029 #ifndef _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE 00030 #define _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE 1 00031 00032 #include <memory> 00033 #include <new> 00034 #include <atomic> 00035 #include <cstddef> 00036 #include <experimental/bits/lfts_config.h> 00037 00038 namespace std { 00039 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00040 00041 namespace experimental { 00042 inline namespace fundamentals_v2 { 00043 namespace pmr { 00044 #define __cpp_lib_experimental_memory_resources 201402L 00045 00046 class memory_resource; 00047 00048 template <typename _Tp> 00049 class polymorphic_allocator; 00050 00051 template <typename _Alloc> 00052 class __resource_adaptor_imp; 00053 00054 template <typename _Alloc> 00055 using resource_adaptor = __resource_adaptor_imp< 00056 typename allocator_traits<_Alloc>::template rebind_alloc<char>>; 00057 00058 template <typename _Tp> 00059 struct __uses_allocator_construction_helper; 00060 00061 // Global memory resources 00062 memory_resource* new_delete_resource() noexcept; 00063 memory_resource* null_memory_resource() noexcept; 00064 00065 // The default memory resource 00066 memory_resource* get_default_resource() noexcept; 00067 memory_resource* set_default_resource(memory_resource* __r) noexcept; 00068 00069 // Standard memory resources 00070 00071 // 8.5 Class memory_resource 00072 class memory_resource 00073 { 00074 protected: 00075 static constexpr size_t _S_max_align = alignof(max_align_t); 00076 00077 public: 00078 virtual ~memory_resource() { } 00079 00080 void* 00081 allocate(size_t __bytes, size_t __alignment = _S_max_align) 00082 { return do_allocate(__bytes, __alignment); } 00083 00084 void 00085 deallocate(void* __p, size_t __bytes, size_t __alignment = _S_max_align) 00086 { return do_deallocate(__p, __bytes, __alignment); } 00087 00088 bool 00089 is_equal(const memory_resource& __other) const noexcept 00090 { return do_is_equal(__other); } 00091 00092 protected: 00093 virtual void* 00094 do_allocate(size_t __bytes, size_t __alignment) = 0; 00095 00096 virtual void 00097 do_deallocate(void* __p, size_t __bytes, size_t __alignment) = 0; 00098 00099 virtual bool 00100 do_is_equal(const memory_resource& __other) const noexcept = 0; 00101 }; 00102 00103 inline bool 00104 operator==(const memory_resource& __a, 00105 const memory_resource& __b) noexcept 00106 { return &__a == &__b || __a.is_equal(__b); } 00107 00108 inline bool 00109 operator!=(const memory_resource& __a, 00110 const memory_resource& __b) noexcept 00111 { return !(__a == __b); } 00112 00113 00114 // 8.6 Class template polymorphic_allocator 00115 template <class _Tp> 00116 class polymorphic_allocator 00117 { 00118 using __uses_alloc1_ = __uses_alloc1<memory_resource*>; 00119 using __uses_alloc2_ = __uses_alloc2<memory_resource*>; 00120 00121 template<typename _Tp1, typename... _Args> 00122 void 00123 _M_construct(__uses_alloc0, _Tp1* __p, _Args&&... __args) 00124 { ::new(__p) _Tp1(std::forward<_Args>(__args)...); } 00125 00126 template<typename _Tp1, typename... _Args> 00127 void 00128 _M_construct(__uses_alloc1_, _Tp1* __p, _Args&&... __args) 00129 { ::new(__p) _Tp1(allocator_arg, this->resource(), 00130 std::forward<_Args>(__args)...); } 00131 00132 template<typename _Tp1, typename... _Args> 00133 void 00134 _M_construct(__uses_alloc2_, _Tp1* __p, _Args&&... __args) 00135 { ::new(__p) _Tp1(std::forward<_Args>(__args)..., 00136 this->resource()); } 00137 00138 public: 00139 using value_type = _Tp; 00140 00141 polymorphic_allocator() noexcept 00142 : _M_resource(get_default_resource()) 00143 { } 00144 00145 polymorphic_allocator(memory_resource* __r) 00146 : _M_resource(__r) 00147 { _GLIBCXX_DEBUG_ASSERT(__r); } 00148 00149 polymorphic_allocator(const polymorphic_allocator& __other) = default; 00150 00151 template <typename _Up> 00152 polymorphic_allocator(const polymorphic_allocator<_Up>& 00153 __other) noexcept 00154 : _M_resource(__other.resource()) 00155 { } 00156 00157 polymorphic_allocator& 00158 operator=(const polymorphic_allocator& __rhs) = default; 00159 00160 _Tp* allocate(size_t __n) 00161 { return static_cast<_Tp*>(_M_resource->allocate(__n * sizeof(_Tp), 00162 alignof(_Tp))); } 00163 00164 void deallocate(_Tp* __p, size_t __n) 00165 { _M_resource->deallocate(__p, __n * sizeof(_Tp), alignof(_Tp)); } 00166 00167 template <typename _Tp1, typename... _Args> //used here 00168 void construct(_Tp1* __p, _Args&&... __args) 00169 { 00170 memory_resource* const __resource = this->resource(); 00171 auto __use_tag 00172 = __use_alloc<_Tp1, memory_resource*, _Args...>(__resource); 00173 _M_construct(__use_tag, __p, std::forward<_Args>(__args)...); 00174 } 00175 00176 // Specializations for pair using piecewise construction 00177 template <typename _Tp1, typename _Tp2, 00178 typename... _Args1, typename... _Args2> 00179 void construct(pair<_Tp1, _Tp2>* __p, piecewise_construct_t, 00180 tuple<_Args1...> __x, 00181 tuple<_Args2...> __y) 00182 { 00183 memory_resource* const __resource = this->resource(); 00184 auto __x_use_tag = 00185 __use_alloc<_Tp1, memory_resource*, _Args1...>(__resource); 00186 auto __y_use_tag = 00187 __use_alloc<_Tp2, memory_resource*, _Args2...>(__resource); 00188 00189 ::new(__p) std::pair<_Tp1, _Tp2>(piecewise_construct, 00190 _M_construct_p(__x_use_tag, __x), 00191 _M_construct_p(__y_use_tag, __y)); 00192 } 00193 00194 template <typename _Tp1, typename _Tp2> 00195 void construct(pair<_Tp1,_Tp2>* __p) 00196 { this->construct(__p, piecewise_construct, tuple<>(), tuple<>()); } 00197 00198 template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp> 00199 void construct(pair<_Tp1,_Tp2>* __p, _Up&& __x, _Vp&& __y) 00200 { this->construct(__p, piecewise_construct, 00201 forward_as_tuple(std::forward<_Up>(__x)), 00202 forward_as_tuple(std::forward<_Vp>(__y))); } 00203 00204 template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp> 00205 void construct(pair<_Tp1,_Tp2>* __p, const std::pair<_Up, _Vp>& __pr) 00206 { this->construct(__p, piecewise_construct, forward_as_tuple(__pr.first), 00207 forward_as_tuple(__pr.second)); } 00208 00209 template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp> 00210 void construct(pair<_Tp1,_Tp2>* __p, pair<_Up, _Vp>&& __pr) 00211 { this->construct(__p, piecewise_construct, 00212 forward_as_tuple(std::forward<_Up>(__pr.first)), 00213 forward_as_tuple(std::forward<_Vp>(__pr.second))); } 00214 00215 template <typename _Up> 00216 void destroy(_Up* __p) 00217 { __p->~_Up(); } 00218 00219 // Return a default-constructed allocator (no allocator propagation) 00220 polymorphic_allocator select_on_container_copy_construction() const 00221 { return polymorphic_allocator(); } 00222 00223 memory_resource* resource() const 00224 { return _M_resource; } 00225 00226 private: 00227 template<typename _Tuple> 00228 _Tuple&& 00229 _M_construct_p(__uses_alloc0, _Tuple& __t) 00230 { return std::move(__t); } 00231 00232 template<typename... _Args> 00233 decltype(auto) 00234 _M_construct_p(__uses_alloc1_ __ua, tuple<_Args...>& __t) 00235 { return tuple_cat(make_tuple(allocator_arg, *(__ua._M_a)), 00236 std::move(__t)); } 00237 00238 template<typename... _Args> 00239 decltype(auto) 00240 _M_construct_p(__uses_alloc2_ __ua, tuple<_Args...>& __t) 00241 { return tuple_cat(std::move(__t), make_tuple(*(__ua._M_a))); } 00242 00243 memory_resource* _M_resource; 00244 }; 00245 00246 template <class _Tp1, class _Tp2> 00247 bool operator==(const polymorphic_allocator<_Tp1>& __a, 00248 const polymorphic_allocator<_Tp2>& __b) noexcept 00249 { return *__a.resource() == *__b.resource(); } 00250 00251 template <class _Tp1, class _Tp2> 00252 bool operator!=(const polymorphic_allocator<_Tp1>& __a, 00253 const polymorphic_allocator<_Tp2>& __b) noexcept 00254 { return !(__a == __b); } 00255 00256 // 8.7.1 __resource_adaptor_imp 00257 template <typename _Alloc> 00258 class __resource_adaptor_imp : public memory_resource 00259 { 00260 static_assert(is_same<char, 00261 typename allocator_traits<_Alloc>::value_type>::value, 00262 "Allocator's value_type is char"); 00263 static_assert(is_same<char*, 00264 typename allocator_traits<_Alloc>::pointer>::value, 00265 "Allocator's pointer type is value_type*"); 00266 static_assert(is_same<const char*, 00267 typename allocator_traits<_Alloc>::const_pointer>::value, 00268 "Allocator's const_pointer type is value_type const*"); 00269 static_assert(is_same<void*, 00270 typename allocator_traits<_Alloc>::void_pointer>::value, 00271 "Allocator's void_pointer type is void*"); 00272 static_assert(is_same<const void*, 00273 typename allocator_traits<_Alloc>::const_void_pointer>::value, 00274 "Allocator's const_void_pointer type is void const*"); 00275 00276 public: 00277 using allocator_type = _Alloc; 00278 00279 __resource_adaptor_imp() = default; 00280 __resource_adaptor_imp(const __resource_adaptor_imp&) = default; 00281 __resource_adaptor_imp(__resource_adaptor_imp&&) = default; 00282 00283 explicit __resource_adaptor_imp(const _Alloc& __a2) 00284 : _M_alloc(__a2) 00285 { } 00286 00287 explicit __resource_adaptor_imp(_Alloc&& __a2) 00288 : _M_alloc(std::move(__a2)) 00289 { } 00290 00291 __resource_adaptor_imp& 00292 operator=(const __resource_adaptor_imp&) = default; 00293 00294 allocator_type get_allocator() const noexcept { return _M_alloc; } 00295 00296 protected: 00297 virtual void* 00298 do_allocate(size_t __bytes, size_t __alignment) 00299 { 00300 using _Aligned_alloc = std::__alloc_rebind<_Alloc, char>; 00301 size_t __new_size = _S_aligned_size(__bytes, 00302 _S_supported(__alignment) ? 00303 __alignment : _S_max_align); 00304 return _Aligned_alloc(_M_alloc).allocate(__new_size); 00305 } 00306 00307 virtual void 00308 do_deallocate(void* __p, size_t __bytes, size_t __alignment) 00309 { 00310 using _Aligned_alloc = std::__alloc_rebind<_Alloc, char>; 00311 size_t __new_size = _S_aligned_size(__bytes, 00312 _S_supported(__alignment) ? 00313 __alignment : _S_max_align); 00314 using _Ptr = typename allocator_traits<_Aligned_alloc>::pointer; 00315 _Aligned_alloc(_M_alloc).deallocate(static_cast<_Ptr>(__p), 00316 __new_size); 00317 } 00318 00319 virtual bool 00320 do_is_equal(const memory_resource& __other) const noexcept 00321 { 00322 auto __p = dynamic_cast<const __resource_adaptor_imp*>(&__other); 00323 return __p ? (_M_alloc == __p->_M_alloc) : false; 00324 } 00325 00326 private: 00327 // Calculate Aligned Size 00328 // Returns a size that is larger than or equal to __size and divisible 00329 // by __alignment, where __alignment is required to be a power of 2. 00330 static size_t 00331 _S_aligned_size(size_t __size, size_t __alignment) 00332 { return ((__size - 1)|(__alignment - 1)) + 1; } 00333 00334 // Determine whether alignment meets one of those preconditions: 00335 // 1. Equal to Zero 00336 // 2. Is power of two 00337 static bool 00338 _S_supported (size_t __x) 00339 { return ((__x != 0) && !(__x & (__x - 1))); } 00340 00341 _Alloc _M_alloc; 00342 }; 00343 00344 // Global memory resources 00345 00346 inline memory_resource* 00347 new_delete_resource() noexcept 00348 { 00349 using type = resource_adaptor<std::allocator<char>>; 00350 alignas(type) static unsigned char __buf[sizeof(type)]; 00351 static type* __r = new(__buf) type; 00352 return __r; 00353 } 00354 00355 inline memory_resource* 00356 null_memory_resource() noexcept 00357 { 00358 class type final : public memory_resource 00359 { 00360 void* 00361 do_allocate(size_t, size_t) override 00362 { std::__throw_bad_alloc(); } 00363 00364 void 00365 do_deallocate(void*, size_t, size_t) noexcept override 00366 { } 00367 00368 bool 00369 do_is_equal(const memory_resource& __other) const noexcept override 00370 { return this == &__other; } 00371 }; 00372 00373 alignas(type) static unsigned char __buf[sizeof(type)]; 00374 static type* __r = new(__buf) type; 00375 return __r; 00376 } 00377 00378 // The default memory resource 00379 00380 inline std::atomic<memory_resource*>& 00381 __get_default_resource() 00382 { 00383 using type = atomic<memory_resource*>; 00384 alignas(type) static unsigned char __buf[sizeof(type)]; 00385 static type* __r = new(__buf) type(new_delete_resource()); 00386 return *__r; 00387 } 00388 00389 inline memory_resource* 00390 get_default_resource() noexcept 00391 { return __get_default_resource().load(); } 00392 00393 inline memory_resource* 00394 set_default_resource(memory_resource* __r) noexcept 00395 { 00396 if (__r == nullptr) 00397 __r = new_delete_resource(); 00398 return __get_default_resource().exchange(__r); 00399 } 00400 } // namespace pmr 00401 } // namespace fundamentals_v2 00402 } // namespace experimental 00403 00404 _GLIBCXX_END_NAMESPACE_VERSION 00405 } // namespace std 00406 00407 #endif