29 #ifndef _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE
30 #define _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE 1
39 namespace experimental {
40 inline namespace fundamentals_v2 {
42 _GLIBCXX_BEGIN_NAMESPACE_VERSION
44 #define __cpp_lib_experimental_memory_resources 201402L
46 class memory_resource;
48 template <
typename _Tp>
49 class polymorphic_allocator;
51 template <
typename _Alloc>
52 class __resource_adaptor_imp;
54 template <
typename _Alloc>
55 using resource_adaptor = __resource_adaptor_imp<
56 typename allocator_traits<_Alloc>::template rebind_alloc<char>>;
58 template <
typename _Tp>
59 struct __uses_allocator_construction_helper;
62 memory_resource* new_delete_resource() noexcept;
63 memory_resource* null_memory_resource() noexcept;
66 memory_resource* get_default_resource() noexcept;
67 memory_resource* set_default_resource(memory_resource* __r) noexcept;
74 static constexpr
size_t _S_max_align =
alignof(max_align_t);
77 virtual ~memory_resource() { }
80 allocate(
size_t __bytes,
size_t __alignment = _S_max_align)
81 {
return do_allocate(__bytes, __alignment); }
84 deallocate(
void* __p,
size_t __bytes,
size_t __alignment = _S_max_align)
85 {
return do_deallocate(__p, __bytes, __alignment); }
88 is_equal(
const memory_resource& __other)
const noexcept
89 {
return do_is_equal(__other); }
93 do_allocate(
size_t __bytes,
size_t __alignment) = 0;
96 do_deallocate(
void* __p,
size_t __bytes,
size_t __alignment) = 0;
99 do_is_equal(
const memory_resource& __other)
const noexcept = 0;
103 operator==(
const memory_resource& __a,
104 const memory_resource& __b) noexcept
105 {
return &__a == &__b || __a.is_equal(__b); }
108 operator!=(
const memory_resource& __a,
109 const memory_resource& __b) noexcept
110 {
return !(__a == __b); }
115 class polymorphic_allocator
117 using __uses_alloc1_ = __uses_alloc1<memory_resource*>;
118 using __uses_alloc2_ = __uses_alloc2<memory_resource*>;
120 template<
typename _Tp1,
typename... _Args>
122 _M_construct(__uses_alloc0, _Tp1* __p, _Args&&... __args)
123 { ::new(__p) _Tp1(std::
forward<_Args>(__args)...); }
125 template<typename _Tp1, typename... _Args>
127 _M_construct(__uses_alloc1_, _Tp1* __p, _Args&&... __args)
128 { ::new(__p) _Tp1(allocator_arg, this->resource(),
129 std::
forward<_Args>(__args)...); }
131 template<typename _Tp1, typename... _Args>
133 _M_construct(__uses_alloc2_, _Tp1* __p, _Args&&... __args)
134 { ::new(__p) _Tp1(std::
forward<_Args>(__args)...,
138 using value_type = _Tp;
140 polymorphic_allocator() noexcept
141 : _M_resource(get_default_resource())
144 polymorphic_allocator(memory_resource* __r)
146 { _GLIBCXX_DEBUG_ASSERT(__r); }
148 polymorphic_allocator(
const polymorphic_allocator& __other) =
default;
150 template <
typename _Up>
151 polymorphic_allocator(
const polymorphic_allocator<_Up>&
153 : _M_resource(__other.resource())
156 polymorphic_allocator&
157 operator=(
const polymorphic_allocator& __rhs) =
default;
159 _Tp* allocate(
size_t __n)
160 {
return static_cast<_Tp*
>(_M_resource->allocate(__n *
sizeof(_Tp),
163 void deallocate(_Tp* __p,
size_t __n)
164 { _M_resource->deallocate(__p, __n *
sizeof(_Tp),
alignof(_Tp)); }
166 template <
typename _Tp1,
typename... _Args>
167 void construct(_Tp1* __p, _Args&&... __args)
169 auto __use_tag = __use_alloc<_Tp1, memory_resource*,
170 _Args...>(this->resource());
171 _M_construct(__use_tag, __p, std::forward<_Args>(__args)...);
175 template <
typename _Tp1,
typename _Tp2,
176 typename... _Args1,
typename... _Args2>
177 void construct(pair<_Tp1, _Tp2>* __p, piecewise_construct_t,
178 tuple<_Args1...> __x,
179 tuple<_Args2...> __y)
182 __use_alloc<_Tp1, memory_resource*, _Args1...>(this->resource());
184 __use_alloc<_Tp2, memory_resource*, _Args2...>(this->resource());
187 _M_construct_p(__x_use_tag, __x),
188 _M_construct_p(__y_use_tag, __y));
191 template <typename _Tp1, typename _Tp2>
192 void construct(pair<_Tp1,_Tp2>* __p)
193 { this->construct(__p, piecewise_construct, tuple<>(), tuple<>()); }
195 template <
typename _Tp1,
typename _Tp2,
typename _Up,
typename _Vp>
196 void construct(pair<_Tp1,_Tp2>* __p, _Up&& __x, _Vp&& __y)
197 { this->construct(__p, piecewise_construct,
198 forward_as_tuple(std::forward<_Up>(__x)),
199 forward_as_tuple(std::forward<_Vp>(__y))); }
201 template <
typename _Tp1,
typename _Tp2,
typename _Up,
typename _Vp>
203 { this->construct(__p, piecewise_construct, forward_as_tuple(__pr.
first),
204 forward_as_tuple(__pr.
second)); }
206 template <
typename _Tp1,
typename _Tp2,
typename _Up,
typename _Vp>
207 void construct(pair<_Tp1,_Tp2>* __p, pair<_Up, _Vp>&& __pr)
208 { this->construct(__p, piecewise_construct,
209 forward_as_tuple(std::forward<_Up>(__pr.
first)),
210 forward_as_tuple(std::forward<_Vp>(__pr.
second))); }
212 template <
typename _Up>
213 void destroy(_Up* __p)
217 polymorphic_allocator select_on_container_copy_construction()
const
218 {
return polymorphic_allocator(); }
220 memory_resource* resource()
const
221 {
return _M_resource; }
224 template<
typename _Tuple>
226 _M_construct_p(__uses_alloc0, _Tuple& __t)
227 {
return std::move(__t); }
229 template<
typename... _Args>
231 _M_construct_p(__uses_alloc1_ __ua, tuple<_Args...>& __t)
232 {
return tuple_cat(make_tuple(allocator_arg, *(__ua._M_a)),
235 template<
typename... _Args>
237 _M_construct_p(__uses_alloc2_ __ua, tuple<_Args...>& __t)
238 {
return tuple_cat(std::move(__t), make_tuple(*(__ua._M_a))); }
240 memory_resource* _M_resource;
243 template <
class _Tp1,
class _Tp2>
244 bool operator==(
const polymorphic_allocator<_Tp1>& __a,
245 const polymorphic_allocator<_Tp2>& __b) noexcept
246 {
return *__a.resource() == *__b.resource(); }
248 template <
class _Tp1,
class _Tp2>
249 bool operator!=(
const polymorphic_allocator<_Tp1>& __a,
250 const polymorphic_allocator<_Tp2>& __b) noexcept
251 {
return !(__a == __b); }
254 template <
typename _Alloc>
255 class __resource_adaptor_imp :
public memory_resource
258 using allocator_type = _Alloc;
260 __resource_adaptor_imp() =
default;
261 __resource_adaptor_imp(
const __resource_adaptor_imp&) =
default;
262 __resource_adaptor_imp(__resource_adaptor_imp&&) =
default;
264 explicit __resource_adaptor_imp(
const _Alloc& __a2)
268 explicit __resource_adaptor_imp(_Alloc&& __a2)
269 : _M_alloc(std::move(__a2))
272 __resource_adaptor_imp&
273 operator=(
const __resource_adaptor_imp&) =
default;
275 allocator_type get_allocator()
const {
return _M_alloc; }
279 do_allocate(
size_t __bytes,
size_t __alignment)
281 using _Aligned_alloc = std::__alloc_rebind<_Alloc, char>;
282 size_t __new_size = _S_aligned_size(__bytes,
283 _S_supported(__alignment) ?
284 __alignment : _S_max_align);
285 return _Aligned_alloc().allocate(__new_size);
289 do_deallocate(
void* __p,
size_t __bytes,
size_t __alignment)
291 using _Aligned_alloc = std::__alloc_rebind<_Alloc, char>;
292 size_t __new_size = _S_aligned_size(__bytes,
293 _S_supported(__alignment) ?
294 __alignment : _S_max_align);
295 _Aligned_alloc().deallocate(
static_cast<typename
296 _Aligned_alloc::pointer
>(__p),
301 do_is_equal(
const memory_resource& __other)
const noexcept
303 auto __p =
dynamic_cast<const __resource_adaptor_imp*
>(&__other);
304 return __p ? (_M_alloc == __p->_M_alloc) :
false;
312 _S_aligned_size(
size_t __size,
size_t __alignment)
313 {
return ((__size - 1)|(__alignment - 1)) + 1; }
319 _S_supported (
size_t __x)
320 {
return ((__x != 0) && !(__x & (__x - 1))); }
327 __get_default_resource()
329 static atomic<memory_resource*> _S_default_resource(new_delete_resource());
330 return _S_default_resource;
333 inline memory_resource*
334 new_delete_resource() noexcept
336 static resource_adaptor<std::allocator<char>> __r;
337 return static_cast<memory_resource*
>(&__r);
340 template <
typename _Alloc>
341 class __null_memory_resource :
private memory_resource
345 do_allocate(
size_t __bytes,
size_t __alignment)
346 { std::__throw_bad_alloc(); }
349 do_deallocate(
void* __p,
size_t __bytes,
size_t __alignment)
353 do_is_equal(
const memory_resource& __other)
const noexcept
356 friend memory_resource* null_memory_resource() noexcept;
359 inline memory_resource*
360 null_memory_resource() noexcept
362 static __null_memory_resource<void> __r;
363 return static_cast<memory_resource*
>(&__r);
367 inline memory_resource*
368 get_default_resource() noexcept
369 {
return __get_default_resource().load(); }
371 inline memory_resource*
372 set_default_resource(memory_resource* __r) noexcept
375 __r = new_delete_resource();
376 return __get_default_resource().exchange(__r);
379 _GLIBCXX_END_NAMESPACE_VERSION
Generic atomic type, primary class template.
constexpr piecewise_construct_t piecewise_construct
piecewise_construct
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
_T2 second
first is a copy of the first object
Struct holding two objects of arbitrary type.
_T1 first
second_type is the second bound type