mirror of
https://github.com/autc04/Retro68.git
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532 lines
16 KiB
C++
532 lines
16 KiB
C++
// <experimental/memory_resource> -*- C++ -*-
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// Copyright (C) 2015-2019 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file experimental/memory_resource
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* This is a TS C++ Library header.
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*/
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#ifndef _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE
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#define _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE 1
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#include <memory> // align, uses_allocator, __uses_alloc
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#include <experimental/utility> // pair, experimental::erased_type
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#include <atomic> // atomic
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#include <new> // placement new
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#include <cstddef> // max_align_t
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#include <ext/new_allocator.h>
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#include <debug/assertions.h>
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namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<typename _Tp> class malloc_allocator;
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace __gnu_cxx
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namespace std {
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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namespace experimental {
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inline namespace fundamentals_v2 {
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namespace pmr {
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#define __cpp_lib_experimental_memory_resources 201402L
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// Standard memory resources
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// 8.5 Class memory_resource
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class memory_resource;
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// 8.6 Class template polymorphic_allocator
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template<typename _Tp>
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class polymorphic_allocator;
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template<typename _Alloc, typename _Resource = memory_resource>
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class __resource_adaptor_imp;
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// 8.7 Alias template resource_adaptor
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template<typename _Alloc>
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using resource_adaptor = __resource_adaptor_imp<
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typename allocator_traits<_Alloc>::template rebind_alloc<char>>;
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// 8.8 Global memory resources
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memory_resource* new_delete_resource() noexcept;
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memory_resource* null_memory_resource() noexcept;
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memory_resource* get_default_resource() noexcept;
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memory_resource* set_default_resource(memory_resource* __r) noexcept;
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// TODO 8.9 Pool resource classes
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class memory_resource
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{
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static constexpr size_t _S_max_align = alignof(max_align_t);
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public:
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memory_resource() = default;
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memory_resource(const memory_resource&) = default;
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virtual ~memory_resource() = default;
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memory_resource& operator=(const memory_resource&) = default;
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_GLIBCXX_NODISCARD void*
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allocate(size_t __bytes, size_t __alignment = _S_max_align)
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{ return do_allocate(__bytes, __alignment); }
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void
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deallocate(void* __p, size_t __bytes, size_t __alignment = _S_max_align)
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{ return do_deallocate(__p, __bytes, __alignment); }
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bool
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is_equal(const memory_resource& __other) const noexcept
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{ return do_is_equal(__other); }
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protected:
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virtual void*
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do_allocate(size_t __bytes, size_t __alignment) = 0;
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virtual void
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do_deallocate(void* __p, size_t __bytes, size_t __alignment) = 0;
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virtual bool
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do_is_equal(const memory_resource& __other) const noexcept = 0;
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};
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inline bool
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operator==(const memory_resource& __a, const memory_resource& __b) noexcept
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{ return &__a == &__b || __a.is_equal(__b); }
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inline bool
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operator!=(const memory_resource& __a, const memory_resource& __b) noexcept
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{ return !(__a == __b); }
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template<typename _Tp>
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class polymorphic_allocator
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{
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public:
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using value_type = _Tp;
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polymorphic_allocator() noexcept
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: _M_resource(get_default_resource())
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{ }
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polymorphic_allocator(memory_resource* __r)
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: _M_resource(__r)
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{ _GLIBCXX_DEBUG_ASSERT(__r); }
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polymorphic_allocator(const polymorphic_allocator& __other) = default;
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template <typename _Up>
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polymorphic_allocator(const polymorphic_allocator<_Up>&
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__other) noexcept
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: _M_resource(__other.resource())
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{ }
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polymorphic_allocator&
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operator=(const polymorphic_allocator& __rhs) = default;
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_GLIBCXX_NODISCARD _Tp* allocate(size_t __n)
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{ return static_cast<_Tp*>(_M_resource->allocate(__n * sizeof(_Tp),
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alignof(_Tp))); }
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void
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deallocate(_Tp* __p, size_t __n)
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{ _M_resource->deallocate(__p, __n * sizeof(_Tp), alignof(_Tp)); }
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template <typename _Tp1, typename... _Args> //used here
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void
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construct(_Tp1* __p, _Args&&... __args)
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{
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std::__uses_allocator_construct(this->resource(), __p,
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std::forward<_Args>(__args)...);
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}
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// Specializations for pair using piecewise construction
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template <typename _Tp1, typename _Tp2,
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typename... _Args1, typename... _Args2>
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void
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construct(pair<_Tp1, _Tp2>* __p, piecewise_construct_t,
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tuple<_Args1...> __x, tuple<_Args2...> __y)
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{
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memory_resource* const __resource = this->resource();
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auto __x_use_tag =
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std::__use_alloc<_Tp1, memory_resource*, _Args1...>(__resource);
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auto __y_use_tag =
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std::__use_alloc<_Tp2, memory_resource*, _Args2...>(__resource);
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::new(__p) std::pair<_Tp1, _Tp2>(piecewise_construct,
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_M_construct_p(__x_use_tag, __x),
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_M_construct_p(__y_use_tag, __y));
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}
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template <typename _Tp1, typename _Tp2>
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void
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construct(pair<_Tp1,_Tp2>* __p)
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{ this->construct(__p, piecewise_construct, tuple<>(), tuple<>()); }
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template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp>
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void
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construct(pair<_Tp1,_Tp2>* __p, _Up&& __x, _Vp&& __y)
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{
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this->construct(__p, piecewise_construct,
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forward_as_tuple(std::forward<_Up>(__x)),
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forward_as_tuple(std::forward<_Vp>(__y)));
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}
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template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp>
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void
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construct(pair<_Tp1,_Tp2>* __p, const std::pair<_Up, _Vp>& __pr)
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{
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this->construct(__p, piecewise_construct,
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forward_as_tuple(__pr.first),
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forward_as_tuple(__pr.second));
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}
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template <typename _Tp1, typename _Tp2, typename _Up, typename _Vp>
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void
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construct(pair<_Tp1,_Tp2>* __p, pair<_Up, _Vp>&& __pr)
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{
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this->construct(__p, piecewise_construct,
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forward_as_tuple(std::forward<_Up>(__pr.first)),
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forward_as_tuple(std::forward<_Vp>(__pr.second)));
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}
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template <typename _Up>
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void
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destroy(_Up* __p)
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{ __p->~_Up(); }
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// Return a default-constructed allocator (no allocator propagation)
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polymorphic_allocator
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select_on_container_copy_construction() const
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{ return polymorphic_allocator(); }
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memory_resource* resource() const { return _M_resource; }
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private:
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using __uses_alloc1_ = __uses_alloc1<memory_resource*>;
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using __uses_alloc2_ = __uses_alloc2<memory_resource*>;
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template<typename _Tuple>
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_Tuple&&
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_M_construct_p(__uses_alloc0, _Tuple& __t)
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{ return std::move(__t); }
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template<typename... _Args>
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decltype(auto)
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_M_construct_p(__uses_alloc1_ __ua, tuple<_Args...>& __t)
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{ return tuple_cat(make_tuple(allocator_arg, *(__ua._M_a)),
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std::move(__t)); }
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template<typename... _Args>
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decltype(auto)
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_M_construct_p(__uses_alloc2_ __ua, tuple<_Args...>& __t)
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{ return tuple_cat(std::move(__t), make_tuple(*(__ua._M_a))); }
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memory_resource* _M_resource;
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};
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template <class _Tp1, class _Tp2>
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bool
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operator==(const polymorphic_allocator<_Tp1>& __a,
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const polymorphic_allocator<_Tp2>& __b) noexcept
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{ return *__a.resource() == *__b.resource(); }
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template <class _Tp1, class _Tp2>
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bool
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operator!=(const polymorphic_allocator<_Tp1>& __a,
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const polymorphic_allocator<_Tp2>& __b) noexcept
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{ return !(__a == __b); }
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class __resource_adaptor_common
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{
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template<typename, typename> friend class __resource_adaptor_imp;
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struct _AlignMgr
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{
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_AlignMgr(size_t __nbytes, size_t __align)
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: _M_nbytes(__nbytes), _M_align(__align)
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{ }
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// Total size that needs to be allocated.
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size_t
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_M_alloc_size() const { return _M_buf_size() + _M_token_size(); }
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void*
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_M_adjust(void* __ptr) const
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{
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const auto __orig_ptr = static_cast<char*>(__ptr);
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size_t __space = _M_buf_size();
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// Align the pointer within the buffer:
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std::align(_M_align, _M_nbytes, __ptr, __space);
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const auto __aligned_ptr = static_cast<char*>(__ptr);
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const auto __token_size = _M_token_size();
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// Store token immediately after the aligned block:
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char* const __end = __aligned_ptr + _M_nbytes;
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if (__token_size == 1)
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_S_write<unsigned char>(__end, __aligned_ptr - __orig_ptr);
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else if (__token_size == sizeof(short))
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_S_write<unsigned short>(__end, __aligned_ptr - __orig_ptr);
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else if (__token_size == sizeof(int) && sizeof(int) < sizeof(char*))
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_S_write<unsigned int>(__end, __aligned_ptr - __orig_ptr);
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else // (__token_size == sizeof(char*))
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// Just store the original pointer:
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_S_write<char*>(__end, __orig_ptr);
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return __aligned_ptr;
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}
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char*
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_M_unadjust(char* __ptr) const
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{
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const char* const __end = __ptr + _M_nbytes;
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char* __orig_ptr;
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const auto __token_size = _M_token_size();
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// Read the token and restore the original pointer:
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if (__token_size == 1)
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__orig_ptr = __ptr - _S_read<unsigned char>(__end);
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else if (__token_size == sizeof(short))
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__orig_ptr = __ptr - _S_read<unsigned short>(__end);
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else if (__token_size == sizeof(int)
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&& sizeof(int) < sizeof(char*))
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__orig_ptr = __ptr - _S_read<unsigned int>(__end);
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else // (__token_size == sizeof(char*))
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__orig_ptr = _S_read<char*>(__end);
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// The adjustment is always less than the requested alignment,
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// so if that isn't true now then either the wrong size was passed
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// to deallocate or the token was overwritten by a buffer overflow:
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__glibcxx_assert(static_cast<size_t>(__ptr - __orig_ptr) < _M_align);
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return __orig_ptr;
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}
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private:
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size_t _M_nbytes;
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size_t _M_align;
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// Number of bytes needed to fit block of given size and alignment.
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size_t
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_M_buf_size() const { return _M_nbytes + _M_align - 1; }
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// Number of additional bytes needed to write the token.
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int
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_M_token_size() const
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{
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if (_M_align <= (1ul << __CHAR_BIT__))
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return 1;
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if (_M_align <= (1ul << (sizeof(short) * __CHAR_BIT__)))
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return sizeof(short);
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if (_M_align <= (1ull << (sizeof(int) * __CHAR_BIT__)))
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return sizeof(int);
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return sizeof(char*);
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}
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template<typename _Tp>
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static void
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_S_write(void* __to, _Tp __val)
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{ __builtin_memcpy(__to, &__val, sizeof(_Tp)); }
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template<typename _Tp>
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static _Tp
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_S_read(const void* __from)
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{
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_Tp __val;
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__builtin_memcpy(&__val, __from, sizeof(_Tp));
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return __val;
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}
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};
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template<typename _Alloc>
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struct __guaranteed_alignment : std::integral_constant<size_t, 1> { };
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template<typename _Tp>
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struct __guaranteed_alignment<__gnu_cxx::new_allocator<_Tp>>
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: std::alignment_of<std::max_align_t>::type { };
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template<typename _Tp>
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struct __guaranteed_alignment<__gnu_cxx::malloc_allocator<_Tp>>
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: std::alignment_of<std::max_align_t>::type { };
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#if _GLIBCXX_USE_ALLOCATOR_NEW
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template<typename _Tp>
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struct __guaranteed_alignment<std::allocator<_Tp>>
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: std::alignment_of<std::max_align_t>::type { };
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#endif
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};
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// 8.7.1 __resource_adaptor_imp
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template<typename _Alloc, typename _Resource>
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class __resource_adaptor_imp
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: public _Resource, private __resource_adaptor_common
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{
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using memory_resource = _Resource;
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static_assert(is_same<char,
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typename allocator_traits<_Alloc>::value_type>::value,
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"Allocator's value_type is char");
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static_assert(is_same<char*,
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typename allocator_traits<_Alloc>::pointer>::value,
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"Allocator's pointer type is value_type*");
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static_assert(is_same<const char*,
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typename allocator_traits<_Alloc>::const_pointer>::value,
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"Allocator's const_pointer type is value_type const*");
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static_assert(is_same<void*,
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typename allocator_traits<_Alloc>::void_pointer>::value,
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"Allocator's void_pointer type is void*");
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static_assert(is_same<const void*,
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typename allocator_traits<_Alloc>::const_void_pointer>::value,
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"Allocator's const_void_pointer type is void const*");
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public:
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using allocator_type = _Alloc;
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__resource_adaptor_imp() = default;
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__resource_adaptor_imp(const __resource_adaptor_imp&) = default;
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__resource_adaptor_imp(__resource_adaptor_imp&&) = default;
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explicit __resource_adaptor_imp(const _Alloc& __a2)
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: _M_alloc(__a2)
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{ }
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explicit __resource_adaptor_imp(_Alloc&& __a2)
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: _M_alloc(std::move(__a2))
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{ }
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__resource_adaptor_imp&
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operator=(const __resource_adaptor_imp&) = default;
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allocator_type get_allocator() const noexcept { return _M_alloc; }
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protected:
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virtual void*
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do_allocate(size_t __bytes, size_t __alignment) override
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{
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if (__alignment <= __guaranteed_alignment<_Alloc>::value)
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{
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if (__bytes < __alignment)
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__bytes = __alignment;
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return _M_alloc.allocate(__bytes);
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}
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const _AlignMgr __mgr(__bytes, __alignment);
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// Assume _M_alloc returns 1-byte aligned memory, so allocate enough
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// space to fit a block of the right size and alignment, plus some
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// extra bytes to store a token for retrieving the original pointer.
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return __mgr._M_adjust(_M_alloc.allocate(__mgr._M_alloc_size()));
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}
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virtual void
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do_deallocate(void* __p, size_t __bytes, size_t __alignment) noexcept
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override
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{
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auto __ptr = static_cast<char*>(__p);
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if (__alignment <= __guaranteed_alignment<_Alloc>::value)
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{
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if (__bytes < __alignment)
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__bytes = __alignment;
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_M_alloc.deallocate(__ptr, __bytes);
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return;
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}
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const _AlignMgr __mgr(__bytes, __alignment);
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// Use the stored token to retrieve the original pointer to deallocate.
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_M_alloc.deallocate(__mgr._M_unadjust(__ptr), __mgr._M_alloc_size());
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}
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virtual bool
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do_is_equal(const memory_resource& __other) const noexcept override
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{
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if (auto __p = dynamic_cast<const __resource_adaptor_imp*>(&__other))
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return _M_alloc == __p->_M_alloc;
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return false;
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}
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private:
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_Alloc _M_alloc{};
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};
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// Global memory resources
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inline memory_resource*
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new_delete_resource() noexcept
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{
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using type = resource_adaptor<__gnu_cxx::new_allocator<char>>;
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alignas(type) static unsigned char __buf[sizeof(type)];
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static type* __r = new(__buf) type;
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return __r;
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}
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inline memory_resource*
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null_memory_resource() noexcept
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{
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class type final : public memory_resource
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{
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void*
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do_allocate(size_t, size_t) override
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{ std::__throw_bad_alloc(); }
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void
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do_deallocate(void*, size_t, size_t) noexcept override
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{ }
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bool
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do_is_equal(const memory_resource& __other) const noexcept override
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{ return this == &__other; }
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};
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alignas(type) static unsigned char __buf[sizeof(type)];
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static type* __r = new(__buf) type;
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return __r;
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}
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// The default memory resource
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inline std::atomic<memory_resource*>&
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__get_default_resource()
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|
{
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|
using type = atomic<memory_resource*>;
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alignas(type) static unsigned char __buf[sizeof(type)];
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|
static type* __r = new(__buf) type(new_delete_resource());
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|
return *__r;
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|
}
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|
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inline memory_resource*
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|
get_default_resource() noexcept
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|
{ return __get_default_resource().load(); }
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|
|
|
inline memory_resource*
|
|
set_default_resource(memory_resource* __r) noexcept
|
|
{
|
|
if (__r == nullptr)
|
|
__r = new_delete_resource();
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|
return __get_default_resource().exchange(__r);
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|
}
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|
|
|
} // namespace pmr
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|
} // namespace fundamentals_v2
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|
} // namespace experimental
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|
|
|
_GLIBCXX_END_NAMESPACE_VERSION
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|
} // namespace std
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|
#endif // _GLIBCXX_EXPERIMENTAL_MEMORY_RESOURCE
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