libcxx/include/experimental/memory_resource - rust-lang/llvm-project - Git at Google

 // -*- C++ -*-
 //===------------------------ memory_resource -----------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//

 #ifndef _LIBCPP_EXPERIMENTAL_MEMORY_RESOURCE
 #define _LIBCPP_EXPERIMENTAL_MEMORY_RESOURCE

 /**
     experimental/memory_resource synopsis

 // C++1y

 namespace std {
 namespace experimental {
 inline namespace fundamentals_v1 {
 namespace pmr {

   class memory_resource;

   bool operator==(const memory_resource& a,
                   const memory_resource& b) noexcept;
   bool operator!=(const memory_resource& a,
                   const memory_resource& b) noexcept;

   template <class Tp> class polymorphic_allocator;

   template <class T1, class T2>
   bool operator==(const polymorphic_allocator<T1>& a,
                   const polymorphic_allocator<T2>& b) noexcept;
   template <class T1, class T2>
   bool operator!=(const polymorphic_allocator<T1>& a,
                   const polymorphic_allocator<T2>& b) noexcept;

   // The name resource_adaptor_imp is for exposition only.
   template <class Allocator> class resource_adaptor_imp;

   template <class Allocator>
     using resource_adaptor = resource_adaptor_imp<
       allocator_traits<Allocator>::rebind_alloc<char>>;

   // Global memory resources
   memory_resource* new_delete_resource() noexcept;
   memory_resource* null_memory_resource() noexcept;

   // The default memory resource
   memory_resource* set_default_resource(memory_resource* r) noexcept;
   memory_resource* get_default_resource() noexcept;

   // Standard memory resources
   struct pool_options;
   class synchronized_pool_resource;
   class unsynchronized_pool_resource;
   class monotonic_buffer_resource;

 } // namespace pmr
 } // namespace fundamentals_v1
 } // namespace experimental
 } // namespace std

  */

 #include <experimental/__config>
 #include <experimental/__memory>
 #include <limits>
 #include <memory>
 #include <new>
 #include <stdexcept>
 #include <__tuple>
 #include <type_traits>
 #include <utility>
 #include <cstddef>
 #include <cstdlib>
 #include <__debug>

 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif

 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>

 _LIBCPP_BEGIN_NAMESPACE_LFTS_PMR

 // Round __s up to next multiple of __a.
 inline _LIBCPP_INLINE_VISIBILITY
 size_t __aligned_allocation_size(size_t __s, size_t __a) _NOEXCEPT
 {
     _LIBCPP_ASSERT(__s + __a > __s, "aligned allocation size overflows");
     return (__s + __a - 1) & ~(__a - 1);
 }

 // 8.5, memory.resource
 class _LIBCPP_TYPE_VIS memory_resource
 {
     static const size_t __max_align = _LIBCPP_ALIGNOF(max_align_t);

 // 8.5.2, memory.resource.public
 public:
     virtual ~memory_resource() = default;

     _LIBCPP_INLINE_VISIBILITY
     void* allocate(size_t __bytes, size_t __align = __max_align)
         { return do_allocate(__bytes, __align); }

     _LIBCPP_INLINE_VISIBILITY
     void deallocate(void * __p, size_t __bytes, size_t __align = __max_align)
         { do_deallocate(__p, __bytes, __align); }

     _LIBCPP_INLINE_VISIBILITY
     bool is_equal(memory_resource const & __other) const _NOEXCEPT
         { return do_is_equal(__other); }

 // 8.5.3, memory.resource.priv
 protected:
     virtual void* do_allocate(size_t, size_t) = 0;
     virtual void do_deallocate(void*, size_t, size_t) = 0;
     virtual bool do_is_equal(memory_resource const &) const _NOEXCEPT = 0;
 };

 // 8.5.4, memory.resource.eq
 inline _LIBCPP_INLINE_VISIBILITY
 bool operator==(memory_resource const & __lhs,
                 memory_resource const & __rhs) _NOEXCEPT
 {
     return &__lhs == &__rhs || __lhs.is_equal(__rhs);
 }

 inline _LIBCPP_INLINE_VISIBILITY
 bool operator!=(memory_resource const & __lhs,
                 memory_resource const & __rhs) _NOEXCEPT
 {
     return !(__lhs == __rhs);
 }

 _LIBCPP_FUNC_VIS
 memory_resource * new_delete_resource() _NOEXCEPT;

 _LIBCPP_FUNC_VIS
 memory_resource * null_memory_resource() _NOEXCEPT;

 _LIBCPP_FUNC_VIS
 memory_resource * get_default_resource() _NOEXCEPT;

 _LIBCPP_FUNC_VIS
 memory_resource * set_default_resource(memory_resource * __new_res) _NOEXCEPT;

 // 8.6, memory.polymorphic.allocator.class

 // 8.6.1, memory.polymorphic.allocator.overview
 template <class _ValueType>
 class _LIBCPP_TEMPLATE_VIS polymorphic_allocator
 {
 public:
     typedef _ValueType value_type;

     // 8.6.2, memory.polymorphic.allocator.ctor
     _LIBCPP_INLINE_VISIBILITY
     polymorphic_allocator() _NOEXCEPT
       : __res_(_VSTD_LFTS_PMR::get_default_resource())
     {}

     _LIBCPP_INLINE_VISIBILITY
     polymorphic_allocator(memory_resource * __r) _NOEXCEPT
       : __res_(__r)
     {}

     polymorphic_allocator(polymorphic_allocator const &) = default;

     template <class _Tp>
     _LIBCPP_INLINE_VISIBILITY
     polymorphic_allocator(polymorphic_allocator<_Tp> const & __other) _NOEXCEPT
       : __res_(__other.resource())
     {}

     polymorphic_allocator &
     operator=(polymorphic_allocator const &) = delete;

     // 8.6.3, memory.polymorphic.allocator.mem
     _LIBCPP_INLINE_VISIBILITY
     _ValueType* allocate(size_t __n) {
         if (__n > __max_size()) {
             __throw_length_error(
                 "std::experimental::pmr::polymorphic_allocator<T>::allocate(size_t n)"
                 " 'n' exceeds maximum supported size");
         }
         return static_cast<_ValueType*>(
             __res_->allocate(__n * sizeof(_ValueType), _LIBCPP_ALIGNOF(_ValueType))
         );
     }

     _LIBCPP_INLINE_VISIBILITY
     void deallocate(_ValueType * __p, size_t __n) _NOEXCEPT {
         _LIBCPP_ASSERT(__n <= __max_size(),
                        "deallocate called for size which exceeds max_size()");
         __res_->deallocate(__p, __n * sizeof(_ValueType), _LIBCPP_ALIGNOF(_ValueType));
     }

     template <class _Tp, class ..._Ts>
     _LIBCPP_INLINE_VISIBILITY
     void construct(_Tp* __p, _Ts &&... __args)
     {
         _VSTD_LFTS::__lfts_user_alloc_construct(
             __p, *this, _VSTD::forward<_Ts>(__args)...
           );
     }

     template <class _T1, class _T2, class ..._Args1, class ..._Args2>
     _LIBCPP_INLINE_VISIBILITY
     void construct(pair<_T1, _T2>* __p, piecewise_construct_t,
                    tuple<_Args1...> __x, tuple<_Args2...> __y)
     {
         ::new ((void*)__p) pair<_T1, _T2>(piecewise_construct
           , __transform_tuple(
               typename __lfts_uses_alloc_ctor<
                   _T1, polymorphic_allocator&, _Args1...
               >::type()
             , _VSTD::move(__x)
             , typename __make_tuple_indices<sizeof...(_Args1)>::type{}
           )
           , __transform_tuple(
               typename __lfts_uses_alloc_ctor<
                   _T2, polymorphic_allocator&, _Args2...
               >::type()
             , _VSTD::move(__y)
             , typename __make_tuple_indices<sizeof...(_Args2)>::type{}
           )
         );
     }

     template <class _T1, class _T2>
     _LIBCPP_INLINE_VISIBILITY
     void construct(pair<_T1, _T2>* __p) {
         construct(__p, piecewise_construct, tuple<>(), tuple<>());
     }

     template <class _T1, class _T2, class _Up, class _Vp>
     _LIBCPP_INLINE_VISIBILITY
     void construct(pair<_T1, _T2> * __p, _Up && __u, _Vp && __v) {
         construct(__p, piecewise_construct
           , _VSTD::forward_as_tuple(_VSTD::forward<_Up>(__u))
           , _VSTD::forward_as_tuple(_VSTD::forward<_Vp>(__v)));
     }

     template <class _T1, class _T2, class _U1, class _U2>
     _LIBCPP_INLINE_VISIBILITY
     void construct(pair<_T1, _T2> * __p, pair<_U1, _U2> const & __pr) {
         construct(__p, piecewise_construct
             , _VSTD::forward_as_tuple(__pr.first)
             , _VSTD::forward_as_tuple(__pr.second));
     }

     template <class _T1, class _T2, class _U1, class _U2>
     _LIBCPP_INLINE_VISIBILITY
     void construct(pair<_T1, _T2> * __p, pair<_U1, _U2> && __pr){
         construct(__p, piecewise_construct
             , _VSTD::forward_as_tuple(_VSTD::forward<_U1>(__pr.first))
             , _VSTD::forward_as_tuple(_VSTD::forward<_U2>(__pr.second)));
     }

     template <class _Tp>
     _LIBCPP_INLINE_VISIBILITY
     void destroy(_Tp * __p) _NOEXCEPT
         { __p->~_Tp(); }

     _LIBCPP_INLINE_VISIBILITY
     polymorphic_allocator
     select_on_container_copy_construction() const _NOEXCEPT
         { return polymorphic_allocator(); }

     _LIBCPP_INLINE_VISIBILITY
     memory_resource * resource() const _NOEXCEPT
         { return __res_; }

 private:
     template <class ..._Args, size_t ..._Idx>
     _LIBCPP_INLINE_VISIBILITY
     tuple<_Args&&...>
     __transform_tuple(integral_constant<int, 0>, tuple<_Args...>&& __t,
                       __tuple_indices<_Idx...>) const
     {
         return _VSTD::forward_as_tuple(_VSTD::get<_Idx>(_VSTD::move(__t))...);
     }

     template <class ..._Args, size_t ..._Idx>
     _LIBCPP_INLINE_VISIBILITY
     tuple<allocator_arg_t const&, polymorphic_allocator&, _Args&&...>
     __transform_tuple(integral_constant<int, 1>, tuple<_Args...> && __t,
                       __tuple_indices<_Idx...>)
     {
         using _Tup = tuple<allocator_arg_t const&, polymorphic_allocator&, _Args&&...>;
         return _Tup(allocator_arg, *this,
                     _VSTD::get<_Idx>(_VSTD::move(__t))...);
     }

     template <class ..._Args, size_t ..._Idx>
     _LIBCPP_INLINE_VISIBILITY
     tuple<_Args&&..., polymorphic_allocator&>
     __transform_tuple(integral_constant<int, 2>, tuple<_Args...> && __t,
                       __tuple_indices<_Idx...>)
     {
         using _Tup = tuple<_Args&&..., polymorphic_allocator&>;
         return _Tup(_VSTD::get<_Idx>(_VSTD::move(__t))..., *this);
     }

     _LIBCPP_INLINE_VISIBILITY
     size_t __max_size() const _NOEXCEPT
         { return numeric_limits<size_t>::max() / sizeof(value_type); }

     memory_resource * __res_;
 };

 // 8.6.4, memory.polymorphic.allocator.eq

 template <class _Tp, class _Up>
 inline _LIBCPP_INLINE_VISIBILITY
 bool operator==(polymorphic_allocator<_Tp> const & __lhs,
                 polymorphic_allocator<_Up> const & __rhs) _NOEXCEPT
 {
     return *__lhs.resource() == *__rhs.resource();
 }

 template <class _Tp, class _Up>
 inline _LIBCPP_INLINE_VISIBILITY
 bool operator!=(polymorphic_allocator<_Tp> const & __lhs,
                 polymorphic_allocator<_Up> const & __rhs) _NOEXCEPT
 {
     return !(__lhs == __rhs);
 }

 // 8.7, memory.resource.adaptor

 // 8.7.1, memory.resource.adaptor.overview
 template <class _CharAlloc>
 class _LIBCPP_TEMPLATE_VIS __resource_adaptor_imp
   : public memory_resource
 {
     using _CTraits = allocator_traits<_CharAlloc>;
     static_assert(is_same<typename _CTraits::value_type, char>::value
                && is_same<typename _CTraits::pointer, char*>::value
                && is_same<typename _CTraits::void_pointer, void*>::value, "");

     static const size_t _MaxAlign = _LIBCPP_ALIGNOF(max_align_t);

     using _Alloc = typename _CTraits::template rebind_alloc<
             typename aligned_storage<_MaxAlign, _MaxAlign>::type
         >;

     using _ValueType = typename _Alloc::value_type;

     _Alloc __alloc_;

 public:
     typedef _CharAlloc allocator_type;

     __resource_adaptor_imp() = default;
     __resource_adaptor_imp(__resource_adaptor_imp const &) = default;
     __resource_adaptor_imp(__resource_adaptor_imp &&) = default;

     // 8.7.2, memory.resource.adaptor.ctor

     _LIBCPP_INLINE_VISIBILITY
     explicit __resource_adaptor_imp(allocator_type const & __a)
       : __alloc_(__a)
     {}

     _LIBCPP_INLINE_VISIBILITY
     explicit __resource_adaptor_imp(allocator_type && __a)
       : __alloc_(_VSTD::move(__a))
     {}

     __resource_adaptor_imp &
     operator=(__resource_adaptor_imp const &) = default;

     _LIBCPP_INLINE_VISIBILITY
     allocator_type get_allocator() const
     { return __alloc_; }

 // 8.7.3, memory.resource.adaptor.mem
 protected:
     virtual void * do_allocate(size_t __bytes, size_t)
     {
         if (__bytes > __max_size()) {
             __throw_length_error(
                 "std::experimental::pmr::resource_adaptor<T>::do_allocate(size_t bytes, size_t align)"
                 " 'bytes' exceeds maximum supported size");
         }
         size_t __s = __aligned_allocation_size(__bytes, _MaxAlign) / _MaxAlign;
         return __alloc_.allocate(__s);
     }

     virtual void do_deallocate(void * __p, size_t __bytes, size_t)
     {
         _LIBCPP_ASSERT(__bytes <= __max_size(),
             "do_deallocate called for size which exceeds the maximum allocation size");
         size_t __s = __aligned_allocation_size(__bytes, _MaxAlign) / _MaxAlign;
         __alloc_.deallocate((_ValueType*)__p, __s);
     }

     virtual bool do_is_equal(memory_resource const & __other) const _NOEXCEPT {
         __resource_adaptor_imp const * __p
           = dynamic_cast<__resource_adaptor_imp const *>(&__other);
         return __p  ? __alloc_ == __p->__alloc_ : false;
     }

 private:
     _LIBCPP_INLINE_VISIBILITY
     size_t __max_size() const _NOEXCEPT {
         return numeric_limits<size_t>::max() - _MaxAlign;
     }
 };

 template <class _Alloc>
 using resource_adaptor = __resource_adaptor_imp<
     typename allocator_traits<_Alloc>::template rebind_alloc<char>
   >;

 _LIBCPP_END_NAMESPACE_LFTS_PMR

 _LIBCPP_POP_MACROS

 #endif /* _LIBCPP_EXPERIMENTAL_MEMORY_RESOURCE */
	// -- C++ --
	//===------------------------ memory_resource -----------------------------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//

	#ifndef _LIBCPP_EXPERIMENTAL_MEMORY_RESOURCE
	#define _LIBCPP_EXPERIMENTAL_MEMORY_RESOURCE

	/**
	experimental/memory_resource synopsis

	// C++1y

	namespace std {
	namespace experimental {
	inline namespace fundamentals_v1 {
	namespace pmr {

	class memory_resource;

	bool operator==(const memory_resource& a,
	const memory_resource& b) noexcept;
	bool operator!=(const memory_resource& a,
	const memory_resource& b) noexcept;

	template <class Tp> class polymorphic_allocator;

	template <class T1, class T2>
	bool operator==(const polymorphic_allocator<T1>& a,
	const polymorphic_allocator<T2>& b) noexcept;
	template <class T1, class T2>
	bool operator!=(const polymorphic_allocator<T1>& a,
	const polymorphic_allocator<T2>& b) noexcept;

	// The name resource_adaptor_imp is for exposition only.
	template <class Allocator> class resource_adaptor_imp;

	template <class Allocator>
	using resource_adaptor = resource_adaptor_imp<
	allocator_traits<Allocator>::rebind_alloc<char>>;

	// Global memory resources
	memory_resource* new_delete_resource() noexcept;
	memory_resource* null_memory_resource() noexcept;

	// The default memory resource
	memory_resource* set_default_resource(memory_resource* r) noexcept;
	memory_resource* get_default_resource() noexcept;

	// Standard memory resources
	struct pool_options;
	class synchronized_pool_resource;
	class unsynchronized_pool_resource;
	class monotonic_buffer_resource;

	} // namespace pmr
	} // namespace fundamentals_v1
	} // namespace experimental
	} // namespace std

	*/

	#include <experimental/__config>
	#include <experimental/__memory>
	#include <limits>
	#include <memory>
	#include <new>
	#include <stdexcept>
	#include <__tuple>
	#include <type_traits>
	#include <utility>
	#include <cstddef>
	#include <cstdlib>
	#include <__debug>

	#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
	#pragma GCC system_header
	#endif

	_LIBCPP_PUSH_MACROS
	#include <__undef_macros>

	_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR

	// Round __s up to next multiple of __a.
	inline _LIBCPP_INLINE_VISIBILITY
	size_t __aligned_allocation_size(size_t __s, size_t __a) _NOEXCEPT
	{
	_LIBCPP_ASSERT(__s + __a > __s, "aligned allocation size overflows");
	return (__s + __a - 1) & ~(__a - 1);
	}

	// 8.5, memory.resource
	class _LIBCPP_TYPE_VIS memory_resource
	{
	static const size_t __max_align = _LIBCPP_ALIGNOF(max_align_t);

	// 8.5.2, memory.resource.public
	public:
	virtual ~memory_resource() = default;

	_LIBCPP_INLINE_VISIBILITY
	void* allocate(size_t __bytes, size_t __align = __max_align)
	{ return do_allocate(__bytes, __align); }

	_LIBCPP_INLINE_VISIBILITY
	void deallocate(void * __p, size_t __bytes, size_t __align = __max_align)
	{ do_deallocate(__p, __bytes, __align); }

	_LIBCPP_INLINE_VISIBILITY
	bool is_equal(memory_resource const & __other) const _NOEXCEPT
	{ return do_is_equal(__other); }

	// 8.5.3, memory.resource.priv
	protected:
	virtual void* do_allocate(size_t, size_t) = 0;
	virtual void do_deallocate(void*, size_t, size_t) = 0;
	virtual bool do_is_equal(memory_resource const &) const _NOEXCEPT = 0;
	};

	// 8.5.4, memory.resource.eq
	inline _LIBCPP_INLINE_VISIBILITY
	bool operator==(memory_resource const & __lhs,
	memory_resource const & __rhs) _NOEXCEPT
	{
	return &__lhs == &__rhs \|\| __lhs.is_equal(__rhs);
	}

	inline _LIBCPP_INLINE_VISIBILITY
	bool operator!=(memory_resource const & __lhs,
	memory_resource const & __rhs) _NOEXCEPT
	{
	return !(__lhs == __rhs);
	}

	_LIBCPP_FUNC_VIS
	memory_resource * new_delete_resource() _NOEXCEPT;

	_LIBCPP_FUNC_VIS
	memory_resource * null_memory_resource() _NOEXCEPT;

	_LIBCPP_FUNC_VIS
	memory_resource * get_default_resource() _NOEXCEPT;

	_LIBCPP_FUNC_VIS
	memory_resource * set_default_resource(memory_resource * __new_res) _NOEXCEPT;

	// 8.6, memory.polymorphic.allocator.class

	// 8.6.1, memory.polymorphic.allocator.overview
	template <class _ValueType>
	class _LIBCPP_TEMPLATE_VIS polymorphic_allocator
	{
	public:
	typedef _ValueType value_type;

	// 8.6.2, memory.polymorphic.allocator.ctor
	_LIBCPP_INLINE_VISIBILITY
	polymorphic_allocator() _NOEXCEPT
	: __res_(_VSTD_LFTS_PMR::get_default_resource())
	{}

	_LIBCPP_INLINE_VISIBILITY
	polymorphic_allocator(memory_resource * __r) _NOEXCEPT
	: __res_(__r)
	{}

	polymorphic_allocator(polymorphic_allocator const &) = default;

	template <class _Tp>
	_LIBCPP_INLINE_VISIBILITY
	polymorphic_allocator(polymorphic_allocator<_Tp> const & __other) _NOEXCEPT
	: __res_(__other.resource())
	{}

	polymorphic_allocator &
	operator=(polymorphic_allocator const &) = delete;

	// 8.6.3, memory.polymorphic.allocator.mem
	_LIBCPP_INLINE_VISIBILITY
	_ValueType* allocate(size_t __n) {
	if (__n > __max_size()) {
	__throw_length_error(
	"std::experimental::pmr::polymorphic_allocator<T>::allocate(size_t n)"
	" 'n' exceeds maximum supported size");
	}
	return static_cast<_ValueType*>(
	__res_->allocate(__n * sizeof(_ValueType), _LIBCPP_ALIGNOF(_ValueType))
	);
	}

	_LIBCPP_INLINE_VISIBILITY
	void deallocate(_ValueType * __p, size_t __n) _NOEXCEPT {
	_LIBCPP_ASSERT(__n <= __max_size(),
	"deallocate called for size which exceeds max_size()");
	__res_->deallocate(__p, __n * sizeof(_ValueType), _LIBCPP_ALIGNOF(_ValueType));
	}

	template <class _Tp, class ..._Ts>
	_LIBCPP_INLINE_VISIBILITY
	void construct(_Tp* __p, _Ts &&... __args)
	{
	_VSTD_LFTS::__lfts_user_alloc_construct(
	__p, *this, _VSTD::forward<_Ts>(__args)...
	);
	}

	template <class _T1, class _T2, class ..._Args1, class ..._Args2>
	_LIBCPP_INLINE_VISIBILITY
	void construct(pair<_T1, _T2>* __p, piecewise_construct_t,
	tuple<_Args1...> __x, tuple<_Args2...> __y)
	{
	::new ((void*)__p) pair<_T1, _T2>(piecewise_construct
	, __transform_tuple(
	typename __lfts_uses_alloc_ctor<
	_T1, polymorphic_allocator&, _Args1...
	>::type()
	, _VSTD::move(__x)
	, typename __make_tuple_indices<sizeof...(_Args1)>::type{}
	)
	, __transform_tuple(
	typename __lfts_uses_alloc_ctor<
	_T2, polymorphic_allocator&, _Args2...
	>::type()
	, _VSTD::move(__y)
	, typename __make_tuple_indices<sizeof...(_Args2)>::type{}
	)
	);
	}

	template <class _T1, class _T2>
	_LIBCPP_INLINE_VISIBILITY
	void construct(pair<_T1, _T2>* __p) {
	construct(__p, piecewise_construct, tuple<>(), tuple<>());
	}

	template <class _T1, class _T2, class _Up, class _Vp>
	_LIBCPP_INLINE_VISIBILITY
	void construct(pair<_T1, _T2> * __p, _Up && __u, _Vp && __v) {
	construct(__p, piecewise_construct
	, _VSTD::forward_as_tuple(_VSTD::forward<_Up>(__u))
	, _VSTD::forward_as_tuple(_VSTD::forward<_Vp>(__v)));
	}

	template <class _T1, class _T2, class _U1, class _U2>
	_LIBCPP_INLINE_VISIBILITY
	void construct(pair<_T1, _T2> * __p, pair<_U1, _U2> const & __pr) {
	construct(__p, piecewise_construct
	, _VSTD::forward_as_tuple(__pr.first)
	, _VSTD::forward_as_tuple(__pr.second));
	}

	template <class _T1, class _T2, class _U1, class _U2>
	_LIBCPP_INLINE_VISIBILITY
	void construct(pair<_T1, _T2> * __p, pair<_U1, _U2> && __pr){
	construct(__p, piecewise_construct
	, _VSTD::forward_as_tuple(_VSTD::forward<_U1>(__pr.first))
	, _VSTD::forward_as_tuple(_VSTD::forward<_U2>(__pr.second)));
	}

	template <class _Tp>
	_LIBCPP_INLINE_VISIBILITY
	void destroy(_Tp * __p) _NOEXCEPT
	{ __p->~_Tp(); }

	_LIBCPP_INLINE_VISIBILITY
	polymorphic_allocator
	select_on_container_copy_construction() const _NOEXCEPT
	{ return polymorphic_allocator(); }

	_LIBCPP_INLINE_VISIBILITY
	memory_resource * resource() const _NOEXCEPT
	{ return __res_; }

	private:
	template <class ..._Args, size_t ..._Idx>
	_LIBCPP_INLINE_VISIBILITY
	tuple<_Args&&...>
	__transform_tuple(integral_constant<int, 0>, tuple<_Args...>&& __t,
	__tuple_indices<_Idx...>) const
	{
	return _VSTD::forward_as_tuple(_VSTD::get<_Idx>(_VSTD::move(__t))...);
	}

	template <class ..._Args, size_t ..._Idx>
	_LIBCPP_INLINE_VISIBILITY
	tuple<allocator_arg_t const&, polymorphic_allocator&, _Args&&...>
	__transform_tuple(integral_constant<int, 1>, tuple<_Args...> && __t,
	__tuple_indices<_Idx...>)
	{
	using _Tup = tuple<allocator_arg_t const&, polymorphic_allocator&, _Args&&...>;
	return _Tup(allocator_arg, *this,
	_VSTD::get<_Idx>(_VSTD::move(__t))...);
	}

	template <class ..._Args, size_t ..._Idx>
	_LIBCPP_INLINE_VISIBILITY
	tuple<_Args&&..., polymorphic_allocator&>
	__transform_tuple(integral_constant<int, 2>, tuple<_Args...> && __t,
	__tuple_indices<_Idx...>)
	{
	using _Tup = tuple<_Args&&..., polymorphic_allocator&>;
	return _Tup(_VSTD::get<_Idx>(_VSTD::move(__t))..., *this);
	}

	_LIBCPP_INLINE_VISIBILITY
	size_t __max_size() const _NOEXCEPT
	{ return numeric_limits<size_t>::max() / sizeof(value_type); }

	memory_resource * __res_;
	};

	// 8.6.4, memory.polymorphic.allocator.eq

	template <class _Tp, class _Up>
	inline _LIBCPP_INLINE_VISIBILITY
	bool operator==(polymorphic_allocator<_Tp> const & __lhs,
	polymorphic_allocator<_Up> const & __rhs) _NOEXCEPT
	{
	return __lhs.resource() == __rhs.resource();
	}

	template <class _Tp, class _Up>
	inline _LIBCPP_INLINE_VISIBILITY
	bool operator!=(polymorphic_allocator<_Tp> const & __lhs,
	polymorphic_allocator<_Up> const & __rhs) _NOEXCEPT
	{
	return !(__lhs == __rhs);
	}

	// 8.7, memory.resource.adaptor

	// 8.7.1, memory.resource.adaptor.overview
	template <class _CharAlloc>
	class _LIBCPP_TEMPLATE_VIS __resource_adaptor_imp
	: public memory_resource
	{
	using _CTraits = allocator_traits<_CharAlloc>;
	static_assert(is_same<typename _CTraits::value_type, char>::value
	&& is_same<typename _CTraits::pointer, char*>::value
	&& is_same<typename _CTraits::void_pointer, void*>::value, "");

	static const size_t _MaxAlign = _LIBCPP_ALIGNOF(max_align_t);

	using _Alloc = typename _CTraits::template rebind_alloc<
	typename aligned_storage<_MaxAlign, _MaxAlign>::type
	>;

	using _ValueType = typename _Alloc::value_type;

	_Alloc __alloc_;

	public:
	typedef _CharAlloc allocator_type;

	__resource_adaptor_imp() = default;
	__resource_adaptor_imp(__resource_adaptor_imp const &) = default;
	__resource_adaptor_imp(__resource_adaptor_imp &&) = default;

	// 8.7.2, memory.resource.adaptor.ctor

	_LIBCPP_INLINE_VISIBILITY
	explicit __resource_adaptor_imp(allocator_type const & __a)
	: __alloc_(__a)
	{}

	_LIBCPP_INLINE_VISIBILITY
	explicit __resource_adaptor_imp(allocator_type && __a)
	: __alloc_(_VSTD::move(__a))
	{}

	__resource_adaptor_imp &
	operator=(__resource_adaptor_imp const &) = default;

	_LIBCPP_INLINE_VISIBILITY
	allocator_type get_allocator() const
	{ return __alloc_; }

	// 8.7.3, memory.resource.adaptor.mem
	protected:
	virtual void * do_allocate(size_t __bytes, size_t)
	{
	if (__bytes > __max_size()) {
	__throw_length_error(
	"std::experimental::pmr::resource_adaptor<T>::do_allocate(size_t bytes, size_t align)"
	" 'bytes' exceeds maximum supported size");
	}
	size_t __s = __aligned_allocation_size(__bytes, _MaxAlign) / _MaxAlign;
	return __alloc_.allocate(__s);
	}

	virtual void do_deallocate(void * __p, size_t __bytes, size_t)
	{
	_LIBCPP_ASSERT(__bytes <= __max_size(),
	"do_deallocate called for size which exceeds the maximum allocation size");
	size_t __s = __aligned_allocation_size(__bytes, _MaxAlign) / _MaxAlign;
	__alloc_.deallocate((_ValueType*)__p, __s);
	}

	virtual bool do_is_equal(memory_resource const & __other) const _NOEXCEPT {
	__resource_adaptor_imp const * __p
	= dynamic_cast<__resource_adaptor_imp const *>(&__other);
	return __p ? __alloc_ == __p->__alloc_ : false;
	}

	private:
	_LIBCPP_INLINE_VISIBILITY
	size_t __max_size() const _NOEXCEPT {
	return numeric_limits<size_t>::max() - _MaxAlign;
	}
	};

	template <class _Alloc>
	using resource_adaptor = __resource_adaptor_imp<
	typename allocator_traits<_Alloc>::template rebind_alloc<char>
	>;

	_LIBCPP_END_NAMESPACE_LFTS_PMR

	_LIBCPP_POP_MACROS

	#endif /* _LIBCPP_EXPERIMENTAL_MEMORY_RESOURCE */