29 #ifndef _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE
30 #define _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE 1
40 namespace experimental {
41 inline namespace fundamentals_v2 {
43 _GLIBCXX_BEGIN_NAMESPACE_VERSION
45 #define __cpp_lib_experimental_memory_resources 201402L
47 class memory_resource;
49 template <
typename _Tp>
50 class polymorphic_allocator;
52 template <
typename _Alloc>
53 class __resource_adaptor_imp;
55 template <
typename _Alloc>
56 using resource_adaptor = __resource_adaptor_imp<
57 typename allocator_traits<_Alloc>::template rebind_alloc<char>>;
59 template <
typename _Tp>
60 struct __uses_allocator_construction_helper;
63 memory_resource* new_delete_resource() noexcept;
64 memory_resource* null_memory_resource() noexcept;
67 memory_resource* get_default_resource() noexcept;
68 memory_resource* set_default_resource(memory_resource* __r) noexcept;
76 static constexpr
size_t _S_max_align =
alignof(max_align_t);
79 virtual ~memory_resource() { }
82 allocate(
size_t __bytes,
size_t __alignment = _S_max_align)
83 {
return do_allocate(__bytes, __alignment); }
86 deallocate(
void* __p,
size_t __bytes,
size_t __alignment = _S_max_align)
87 {
return do_deallocate(__p, __bytes, __alignment); }
90 is_equal(
const memory_resource& __other)
const noexcept
91 {
return do_is_equal(__other); }
95 do_allocate(
size_t __bytes,
size_t __alignment) = 0;
98 do_deallocate(
void* __p,
size_t __bytes,
size_t __alignment) = 0;
101 do_is_equal(
const memory_resource& __other)
const noexcept = 0;
105 operator==(
const memory_resource& __a,
106 const memory_resource& __b) noexcept
107 {
return &__a == &__b || __a.is_equal(__b); }
110 operator!=(
const memory_resource& __a,
111 const memory_resource& __b) noexcept
112 {
return !(__a == __b); }
117 class polymorphic_allocator
119 using __uses_alloc1_ = __uses_alloc1<memory_resource*>;
120 using __uses_alloc2_ = __uses_alloc2<memory_resource*>;
122 template<
typename _Tp1,
typename... _Args>
124 _M_construct(__uses_alloc0, _Tp1* __p, _Args&&... __args)
125 { ::new(__p) _Tp1(std::
forward<_Args>(__args)...); }
127 template<typename _Tp1, typename... _Args>
129 _M_construct(__uses_alloc1_, _Tp1* __p, _Args&&... __args)
130 { ::new(__p) _Tp1(allocator_arg, this->resource(),
131 std::
forward<_Args>(__args)...); }
133 template<typename _Tp1, typename... _Args>
135 _M_construct(__uses_alloc2_, _Tp1* __p, _Args&&... __args)
136 { ::new(__p) _Tp1(std::
forward<_Args>(__args)...,
140 using value_type = _Tp;
142 polymorphic_allocator() noexcept
143 : _M_resource(get_default_resource())
146 polymorphic_allocator(memory_resource* __r)
148 { _GLIBCXX_DEBUG_ASSERT(__r); }
150 polymorphic_allocator(
const polymorphic_allocator& __other) =
default;
152 template <
typename _Up>
153 polymorphic_allocator(
const polymorphic_allocator<_Up>&
155 : _M_resource(__other.resource())
158 polymorphic_allocator&
159 operator=(
const polymorphic_allocator& __rhs) =
default;
161 _Tp* allocate(
size_t __n)
162 {
return static_cast<_Tp*
>(_M_resource->allocate(__n *
sizeof(_Tp),
165 void deallocate(_Tp* __p,
size_t __n)
166 { _M_resource->deallocate(__p, __n *
sizeof(_Tp),
alignof(_Tp)); }
168 template <
typename _Tp1,
typename... _Args>
169 void construct(_Tp1* __p, _Args&&... __args)
171 memory_resource*
const __resource = this->resource();
173 = __use_alloc<_Tp1, memory_resource*, _Args...>(__resource);
174 _M_construct(__use_tag, __p, std::forward<_Args>(__args)...);
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)
184 memory_resource*
const __resource = this->resource();
186 __use_alloc<_Tp1, memory_resource*, _Args1...>(__resource);
188 __use_alloc<_Tp2, memory_resource*, _Args2...>(__resource);
191 _M_construct_p(__x_use_tag, __x),
192 _M_construct_p(__y_use_tag, __y));
195 template <typename _Tp1, typename _Tp2>
196 void construct(pair<_Tp1,_Tp2>* __p)
197 { this->construct(__p, piecewise_construct, tuple<>(), tuple<>()); }
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))); }
205 template <
typename _Tp1,
typename _Tp2,
typename _Up,
typename _Vp>
207 { this->construct(__p, piecewise_construct, forward_as_tuple(__pr.
first),
208 forward_as_tuple(__pr.
second)); }
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))); }
216 template <
typename _Up>
217 void destroy(_Up* __p)
221 polymorphic_allocator select_on_container_copy_construction()
const
222 {
return polymorphic_allocator(); }
224 memory_resource* resource()
const
225 {
return _M_resource; }
228 template<
typename _Tuple>
230 _M_construct_p(__uses_alloc0, _Tuple& __t)
231 {
return std::move(__t); }
233 template<
typename... _Args>
235 _M_construct_p(__uses_alloc1_ __ua, tuple<_Args...>& __t)
236 {
return tuple_cat(make_tuple(allocator_arg, *(__ua._M_a)),
239 template<
typename... _Args>
241 _M_construct_p(__uses_alloc2_ __ua, tuple<_Args...>& __t)
242 {
return tuple_cat(std::move(__t), make_tuple(*(__ua._M_a))); }
244 memory_resource* _M_resource;
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(); }
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); }
258 template <
typename _Alloc>
259 class __resource_adaptor_imp :
public memory_resource
262 using allocator_type = _Alloc;
264 __resource_adaptor_imp() =
default;
265 __resource_adaptor_imp(
const __resource_adaptor_imp&) =
default;
266 __resource_adaptor_imp(__resource_adaptor_imp&&) =
default;
268 explicit __resource_adaptor_imp(
const _Alloc& __a2)
272 explicit __resource_adaptor_imp(_Alloc&& __a2)
273 : _M_alloc(std::move(__a2))
276 __resource_adaptor_imp&
277 operator=(
const __resource_adaptor_imp&) =
default;
279 allocator_type get_allocator()
const {
return _M_alloc; }
283 do_allocate(
size_t __bytes,
size_t __alignment)
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);
293 do_deallocate(
void* __p,
size_t __bytes,
size_t __alignment)
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),
305 do_is_equal(
const memory_resource& __other)
const noexcept
307 auto __p =
dynamic_cast<const __resource_adaptor_imp*
>(&__other);
308 return __p ? (_M_alloc == __p->_M_alloc) :
false;
316 _S_aligned_size(
size_t __size,
size_t __alignment)
317 {
return ((__size - 1)|(__alignment - 1)) + 1; }
323 _S_supported (
size_t __x)
324 {
return ((__x != 0) && !(__x & (__x - 1))); }
331 __get_default_resource()
333 static atomic<memory_resource*> _S_default_resource(new_delete_resource());
334 return _S_default_resource;
337 inline memory_resource*
338 new_delete_resource() noexcept
340 static resource_adaptor<std::allocator<char>> __r;
341 return static_cast<memory_resource*
>(&__r);
344 template <
typename _Alloc>
345 class __null_memory_resource :
private memory_resource
349 do_allocate(
size_t,
size_t)
350 { std::__throw_bad_alloc(); }
353 do_deallocate(
void*,
size_t,
size_t) noexcept
357 do_is_equal(
const memory_resource& __other)
const noexcept
358 {
return this == &__other; }
360 friend memory_resource* null_memory_resource() noexcept;
363 inline memory_resource*
364 null_memory_resource() noexcept
366 static __null_memory_resource<void> __r;
367 return static_cast<memory_resource*
>(&__r);
371 inline memory_resource*
372 get_default_resource() noexcept
373 {
return __get_default_resource().load(); }
375 inline memory_resource*
376 set_default_resource(memory_resource* __r) noexcept
379 __r = new_delete_resource();
380 return __get_default_resource().exchange(__r);
383 _GLIBCXX_END_NAMESPACE_VERSION
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
_GLIBCXX17_INLINE constexpr piecewise_construct_t piecewise_construct
piecewise_construct
_T2 second
first is a copy of the first object
Generic atomic type, primary class template.
Struct holding two objects of arbitrary type.
_T1 first
second_type is the second bound type