libstdc++
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00001 // <experimental/memory_resource> -*- C++ -*- 00002 00003 // Copyright (C) 2015-2016 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 <bits/alloc_traits.h> 00037 00038 namespace std { 00039 namespace experimental { 00040 inline namespace fundamentals_v2 { 00041 namespace pmr { 00042 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00043 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 static constexpr size_t _S_max_align = alignof(max_align_t); 00075 00076 public: 00077 virtual ~memory_resource() { } 00078 00079 void* 00080 allocate(size_t __bytes, size_t __alignment = _S_max_align) 00081 { return do_allocate(__bytes, __alignment); } 00082 00083 void 00084 deallocate(void* __p, size_t __bytes, size_t __alignment = _S_max_align) 00085 { return do_deallocate(__p, __bytes, __alignment); } 00086 00087 bool 00088 is_equal(const memory_resource& __other) const noexcept 00089 { return do_is_equal(__other); } 00090 00091 protected: 00092 virtual void* 00093 do_allocate(size_t __bytes, size_t __alignment) = 0; 00094 00095 virtual void 00096 do_deallocate(void* __p, size_t __bytes, size_t __alignment) = 0; 00097 00098 virtual bool 00099 do_is_equal(const memory_resource& __other) const noexcept = 0; 00100 }; 00101 00102 inline bool 00103 operator==(const memory_resource& __a, 00104 const memory_resource& __b) noexcept 00105 { return &__a == &__b || __a.is_equal(__b); } 00106 00107 inline bool 00108 operator!=(const memory_resource& __a, 00109 const memory_resource& __b) noexcept 00110 { return !(__a == __b); } 00111 00112 00113 // 8.6 Class template polymorphic_allocator 00114 template <class _Tp> 00115 class polymorphic_allocator 00116 { 00117 using __uses_alloc1_ = __uses_alloc1<memory_resource*>; 00118 using __uses_alloc2_ = __uses_alloc2<memory_resource*>; 00119 00120 template<typename _Tp1, typename... _Args> 00121 void 00122 _M_construct(__uses_alloc0, _Tp1* __p, _Args&&... __args) 00123 { ::new(__p) _Tp1(std::forward<_Args>(__args)...); } 00124 00125 template<typename _Tp1, typename... _Args> 00126 void 00127 _M_construct(__uses_alloc1_, _Tp1* __p, _Args&&... __args) 00128 { ::new(__p) _Tp1(allocator_arg, this->resource(), 00129 std::forward<_Args>(__args)...); } 00130 00131 template<typename _Tp1, typename... _Args> 00132 void 00133 _M_construct(__uses_alloc2_, _Tp1* __p, _Args&&... __args) 00134 { ::new(__p) _Tp1(std::forward<_Args>(__args)..., 00135 this->resource()); } 00136 00137 public: 00138 using value_type = _Tp; 00139 00140 polymorphic_allocator() noexcept 00141 : _M_resource(get_default_resource()) 00142 { } 00143 00144 polymorphic_allocator(memory_resource* __r) 00145 : _M_resource(__r) 00146 { _GLIBCXX_DEBUG_ASSERT(__r); } 00147 00148 polymorphic_allocator(const polymorphic_allocator& __other) = default; 00149 00150 template <typename _Up> 00151 polymorphic_allocator(const polymorphic_allocator<_Up>& 00152 __other) noexcept 00153 : _M_resource(__other.resource()) 00154 { } 00155 00156 polymorphic_allocator& 00157 operator=(const polymorphic_allocator& __rhs) = default; 00158 00159 _Tp* allocate(size_t __n) 00160 { return static_cast<_Tp*>(_M_resource->allocate(__n * sizeof(_Tp), 00161 alignof(_Tp))); } 00162 00163 void deallocate(_Tp* __p, size_t __n) 00164 { _M_resource->deallocate(__p, __n * sizeof(_Tp), alignof(_Tp)); } 00165 00166 template <typename _Tp1, typename... _Args> //used here 00167 void construct(_Tp1* __p, _Args&&... __args) 00168 { 00169 auto __use_tag = __use_alloc<_Tp1, memory_resource*, 00170 _Args...>(this->resource()); 00171 _M_construct(__use_tag, __p, std::forward<_Args>(__args)...); 00172 } 00173 00174 // Specializations for pair using piecewise construction 00175 template <typename _Tp1, typename _Tp2, 00176 typename... _Args1, typename... _Args2> 00177 void construct(pair<_Tp1, _Tp2>* __p, piecewise_construct_t, 00178 tuple<_Args1...> __x, 00179 tuple<_Args2...> __y) 00180 { 00181 auto __x_use_tag = 00182 __use_alloc<_Tp1, memory_resource*, _Args1...>(this->resource()); 00183 auto __y_use_tag = 00184 __use_alloc<_Tp2, memory_resource*, _Args2...>(this->resource()); 00185 00186 ::new(__p) std::pair<_Tp1, _Tp2>(piecewise_construct, 00187 _M_construct_p(__x_use_tag, __x), 00188 _M_construct_p(__y_use_tag, __y)); 00189 } 00190 00191 template <typename _Tp1, typename _Tp2> 00192 void construct(pair<_Tp1,_Tp2>* __p) 00193 { this->construct(__p, piecewise_construct, tuple<>(), tuple<>()); } 00194 00195 template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp> 00196 void construct(pair<_Tp1,_Tp2>* __p, _Up&& __x, _Vp&& __y) 00197 { this->construct(__p, piecewise_construct, 00198 forward_as_tuple(std::forward<_Up>(__x)), 00199 forward_as_tuple(std::forward<_Vp>(__y))); } 00200 00201 template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp> 00202 void construct(pair<_Tp1,_Tp2>* __p, const std::pair<_Up, _Vp>& __pr) 00203 { this->construct(__p, piecewise_construct, forward_as_tuple(__pr.first), 00204 forward_as_tuple(__pr.second)); } 00205 00206 template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp> 00207 void construct(pair<_Tp1,_Tp2>* __p, pair<_Up, _Vp>&& __pr) 00208 { this->construct(__p, piecewise_construct, 00209 forward_as_tuple(std::forward<_Up>(__pr.first)), 00210 forward_as_tuple(std::forward<_Vp>(__pr.second))); } 00211 00212 template <typename _Up> 00213 void destroy(_Up* __p) 00214 { __p->~_Up(); } 00215 00216 // Return a default-constructed allocator (no allocator propagation) 00217 polymorphic_allocator select_on_container_copy_construction() const 00218 { return polymorphic_allocator(); } 00219 00220 memory_resource* resource() const 00221 { return _M_resource; } 00222 00223 private: 00224 template<typename _Tuple> 00225 _Tuple&& 00226 _M_construct_p(__uses_alloc0, _Tuple& __t) 00227 { return std::move(__t); } 00228 00229 template<typename... _Args> 00230 decltype(auto) 00231 _M_construct_p(__uses_alloc1_ __ua, tuple<_Args...>& __t) 00232 { return tuple_cat(make_tuple(allocator_arg, *(__ua._M_a)), 00233 std::move(__t)); } 00234 00235 template<typename... _Args> 00236 decltype(auto) 00237 _M_construct_p(__uses_alloc2_ __ua, tuple<_Args...>& __t) 00238 { return tuple_cat(std::move(__t), make_tuple(*(__ua._M_a))); } 00239 00240 memory_resource* _M_resource; 00241 }; 00242 00243 template <class _Tp1, class _Tp2> 00244 bool operator==(const polymorphic_allocator<_Tp1>& __a, 00245 const polymorphic_allocator<_Tp2>& __b) noexcept 00246 { return *__a.resource() == *__b.resource(); } 00247 00248 template <class _Tp1, class _Tp2> 00249 bool operator!=(const polymorphic_allocator<_Tp1>& __a, 00250 const polymorphic_allocator<_Tp2>& __b) noexcept 00251 { return !(__a == __b); } 00252 00253 // 8.7.1 __resource_adaptor_imp 00254 template <typename _Alloc> 00255 class __resource_adaptor_imp : public memory_resource 00256 { 00257 public: 00258 using allocator_type = _Alloc; 00259 00260 __resource_adaptor_imp() = default; 00261 __resource_adaptor_imp(const __resource_adaptor_imp&) = default; 00262 __resource_adaptor_imp(__resource_adaptor_imp&&) = default; 00263 00264 explicit __resource_adaptor_imp(const _Alloc& __a2) 00265 : _M_alloc(__a2) 00266 { } 00267 00268 explicit __resource_adaptor_imp(_Alloc&& __a2) 00269 : _M_alloc(std::move(__a2)) 00270 { } 00271 00272 __resource_adaptor_imp& 00273 operator=(const __resource_adaptor_imp&) = default; 00274 00275 allocator_type get_allocator() const { return _M_alloc; } 00276 00277 protected: 00278 virtual void* 00279 do_allocate(size_t __bytes, size_t __alignment) 00280 { 00281 using _Aligned_alloc = std::__alloc_rebind<_Alloc, char>; 00282 size_t __new_size = _S_aligned_size(__bytes, 00283 _S_supported(__alignment) ? 00284 __alignment : _S_max_align); 00285 return _Aligned_alloc(_M_alloc).allocate(__new_size); 00286 } 00287 00288 virtual void 00289 do_deallocate(void* __p, size_t __bytes, size_t __alignment) 00290 { 00291 using _Aligned_alloc = std::__alloc_rebind<_Alloc, char>; 00292 size_t __new_size = _S_aligned_size(__bytes, 00293 _S_supported(__alignment) ? 00294 __alignment : _S_max_align); 00295 using _Ptr = typename allocator_traits<_Aligned_alloc>::pointer; 00296 _Aligned_alloc(_M_alloc).deallocate(static_cast<_Ptr>(__p), 00297 __new_size); 00298 } 00299 00300 virtual bool 00301 do_is_equal(const memory_resource& __other) const noexcept 00302 { 00303 auto __p = dynamic_cast<const __resource_adaptor_imp*>(&__other); 00304 return __p ? (_M_alloc == __p->_M_alloc) : false; 00305 } 00306 00307 private: 00308 // Calculate Aligned Size 00309 // Returns a size that is larger than or equal to __size and divisible 00310 // by __alignment, where __alignment is required to be the power of 2. 00311 static size_t 00312 _S_aligned_size(size_t __size, size_t __alignment) 00313 { return ((__size - 1)|(__alignment - 1)) + 1; } 00314 00315 // Determine whether alignment meets one of those preconditions: 00316 // 1. Equals to Zero 00317 // 2. Is power of two 00318 static bool 00319 _S_supported (size_t __x) 00320 { return ((__x != 0) && !(__x & (__x - 1))); } 00321 00322 _Alloc _M_alloc; 00323 }; 00324 00325 // Global memory resources 00326 inline std::atomic<memory_resource*>& 00327 __get_default_resource() 00328 { 00329 static atomic<memory_resource*> _S_default_resource(new_delete_resource()); 00330 return _S_default_resource; 00331 } 00332 00333 inline memory_resource* 00334 new_delete_resource() noexcept 00335 { 00336 static resource_adaptor<std::allocator<char>> __r; 00337 return static_cast<memory_resource*>(&__r); 00338 } 00339 00340 template <typename _Alloc> 00341 class __null_memory_resource : private memory_resource 00342 { 00343 protected: 00344 void* 00345 do_allocate(size_t, size_t) 00346 { std::__throw_bad_alloc(); } 00347 00348 void 00349 do_deallocate(void*, size_t, size_t) noexcept 00350 { } 00351 00352 bool 00353 do_is_equal(const memory_resource& __other) const noexcept 00354 { return this == &__other; } 00355 00356 friend memory_resource* null_memory_resource() noexcept; 00357 }; 00358 00359 inline memory_resource* 00360 null_memory_resource() noexcept 00361 { 00362 static __null_memory_resource<void> __r; 00363 return static_cast<memory_resource*>(&__r); 00364 } 00365 00366 // The default memory resource 00367 inline memory_resource* 00368 get_default_resource() noexcept 00369 { return __get_default_resource().load(); } 00370 00371 inline memory_resource* 00372 set_default_resource(memory_resource* __r) noexcept 00373 { 00374 if (__r == nullptr) 00375 __r = new_delete_resource(); 00376 return __get_default_resource().exchange(__r); 00377 } 00378 00379 _GLIBCXX_END_NAMESPACE_VERSION 00380 } // namespace pmr 00381 } // namespace fundamentals_v2 00382 } // namespace experimental 00383 } // namespace std 00384 00385 #endif