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 auto __use_tag = __use_alloc<_Tp1, memory_resource*,
172 _Args...>(this->resource());
173 _M_construct(__use_tag, __p, std::forward<_Args>(__args)...);
177 template <
typename _Tp1,
typename _Tp2,
178 typename... _Args1,
typename... _Args2>
179 void construct(pair<_Tp1, _Tp2>* __p, piecewise_construct_t,
180 tuple<_Args1...> __x,
181 tuple<_Args2...> __y)
184 __use_alloc<_Tp1, memory_resource*, _Args1...>(this->resource());
186 __use_alloc<_Tp2, memory_resource*, _Args2...>(this->resource());
189 _M_construct_p(__x_use_tag, __x),
190 _M_construct_p(__y_use_tag, __y));
193 template <
typename _Tp1,
typename _Tp2>
194 void construct(pair<_Tp1,_Tp2>* __p)
197 template <
typename _Tp1,
typename _Tp2,
typename _Up,
typename _Vp>
198 void construct(pair<_Tp1,_Tp2>* __p, _Up&& __x, _Vp&& __y)
200 forward_as_tuple(std::forward<_Up>(__x)),
201 forward_as_tuple(std::forward<_Vp>(__y))); }
203 template <
typename _Tp1,
typename _Tp2,
typename _Up,
typename _Vp>
206 forward_as_tuple(__pr.
second)); }
208 template <
typename _Tp1,
typename _Tp2,
typename _Up,
typename _Vp>
209 void construct(pair<_Tp1,_Tp2>* __p, pair<_Up, _Vp>&& __pr)
211 forward_as_tuple(std::forward<_Up>(__pr.
first)),
212 forward_as_tuple(std::forward<_Vp>(__pr.
second))); }
214 template <
typename _Up>
215 void destroy(_Up* __p)
219 polymorphic_allocator select_on_container_copy_construction()
const 220 {
return polymorphic_allocator(); }
222 memory_resource* resource()
const 223 {
return _M_resource; }
226 template<
typename _Tuple>
228 _M_construct_p(__uses_alloc0, _Tuple& __t)
229 {
return std::move(__t); }
231 template<
typename... _Args>
233 _M_construct_p(__uses_alloc1_ __ua, tuple<_Args...>& __t)
234 {
return tuple_cat(make_tuple(allocator_arg, *(__ua._M_a)),
237 template<
typename... _Args>
239 _M_construct_p(__uses_alloc2_ __ua, tuple<_Args...>& __t)
240 {
return tuple_cat(std::move(__t), make_tuple(*(__ua._M_a))); }
242 memory_resource* _M_resource;
245 template <
class _Tp1,
class _Tp2>
246 bool operator==(
const polymorphic_allocator<_Tp1>& __a,
247 const polymorphic_allocator<_Tp2>& __b) noexcept
248 {
return *__a.resource() == *__b.resource(); }
250 template <
class _Tp1,
class _Tp2>
251 bool operator!=(
const polymorphic_allocator<_Tp1>& __a,
252 const polymorphic_allocator<_Tp2>& __b) noexcept
253 {
return !(__a == __b); }
256 template <
typename _Alloc>
257 class __resource_adaptor_imp :
public memory_resource
260 using allocator_type = _Alloc;
262 __resource_adaptor_imp() =
default;
263 __resource_adaptor_imp(
const __resource_adaptor_imp&) =
default;
264 __resource_adaptor_imp(__resource_adaptor_imp&&) =
default;
266 explicit __resource_adaptor_imp(
const _Alloc& __a2)
270 explicit __resource_adaptor_imp(_Alloc&& __a2)
271 : _M_alloc(
std::move(__a2))
274 __resource_adaptor_imp&
275 operator=(
const __resource_adaptor_imp&) =
default;
277 allocator_type get_allocator()
const {
return _M_alloc; }
281 do_allocate(
size_t __bytes,
size_t __alignment)
283 using _Aligned_alloc = std::__alloc_rebind<_Alloc, char>;
284 size_t __new_size = _S_aligned_size(__bytes,
285 _S_supported(__alignment) ?
286 __alignment : _S_max_align);
287 return _Aligned_alloc(_M_alloc).allocate(__new_size);
291 do_deallocate(
void* __p,
size_t __bytes,
size_t __alignment)
293 using _Aligned_alloc = std::__alloc_rebind<_Alloc, char>;
294 size_t __new_size = _S_aligned_size(__bytes,
295 _S_supported(__alignment) ?
296 __alignment : _S_max_align);
298 _Aligned_alloc(_M_alloc).deallocate(static_cast<_Ptr>(__p),
303 do_is_equal(
const memory_resource& __other)
const noexcept
305 auto __p =
dynamic_cast<const __resource_adaptor_imp*
>(&__other);
306 return __p ? (_M_alloc == __p->_M_alloc) :
false;
314 _S_aligned_size(
size_t __size,
size_t __alignment)
315 {
return ((__size - 1)|(__alignment - 1)) + 1; }
321 _S_supported (
size_t __x)
322 {
return ((__x != 0) && !(__x & (__x - 1))); }
329 __get_default_resource()
331 static atomic<memory_resource*> _S_default_resource(new_delete_resource());
332 return _S_default_resource;
335 inline memory_resource*
336 new_delete_resource() noexcept
338 static resource_adaptor<std::allocator<char>> __r;
339 return static_cast<memory_resource*
>(&__r);
342 template <
typename _Alloc>
343 class __null_memory_resource :
private memory_resource
347 do_allocate(
size_t,
size_t)
348 { std::__throw_bad_alloc(); }
351 do_deallocate(
void*,
size_t,
size_t) noexcept
355 do_is_equal(
const memory_resource& __other)
const noexcept
356 {
return this == &__other; }
358 friend memory_resource* null_memory_resource() noexcept;
361 inline memory_resource*
362 null_memory_resource() noexcept
364 static __null_memory_resource<void> __r;
365 return static_cast<memory_resource*
>(&__r);
369 inline memory_resource*
370 get_default_resource() noexcept
371 {
return __get_default_resource().load(); }
373 inline memory_resource*
374 set_default_resource(memory_resource* __r) noexcept
377 __r = new_delete_resource();
378 return __get_default_resource().exchange(__r);
381 _GLIBCXX_END_NAMESPACE_VERSION
_T2 second
first is a copy of the first object
__detected_or_t< value_type *, __pointer, _Alloc > pointer
The allocator's pointer type.
ISO C++ entities toplevel namespace is std.
constexpr auto tuple_cat(_Tpls &&... __tpls) -> typename __tuple_cat_result< _Tpls... >::__type
tuple_cat
constexpr piecewise_construct_t piecewise_construct
piecewise_construct
Generic atomic type, primary class template.
_T1 first
second_type is the second bound type
Struct holding two objects of arbitrary type.