//////////////////////////////////////////////////////////////////////////////
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//
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// (C) Copyright Ion Gaztanaga 2015-2015. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org/libs/container for documentation.
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//
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//////////////////////////////////////////////////////////////////////////////
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#ifndef BOOST_CONTAINER_PMR_RESOURCE_ADAPTOR_HPP
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#define BOOST_CONTAINER_PMR_RESOURCE_ADAPTOR_HPP
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#if defined (_MSC_VER)
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# pragma once
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#endif
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#include <boost/container/detail/config_begin.hpp>
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#include <boost/container/detail/workaround.hpp>
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#include <boost/container/container_fwd.hpp>
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#include <boost/container/pmr/memory_resource.hpp>
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#include <boost/container/allocator_traits.hpp>
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#include <boost/intrusive/detail/ebo_functor_holder.hpp>
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#include <boost/move/utility_core.hpp>
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#include <boost/move/detail/type_traits.hpp>
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#include <boost/container/detail/std_fwd.hpp>
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#include <cstring>
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namespace boost {
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namespace container {
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namespace pmr_dtl {
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template<class T>
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struct max_allocator_alignment
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{
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static const std::size_t value = 1;
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};
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template<class T>
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struct max_allocator_alignment< ::boost::container::new_allocator<T> >
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{
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static const std::size_t value = boost::move_detail::alignment_of<boost::move_detail::max_align_t>::value;
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};
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template<class T>
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struct max_allocator_alignment< std::allocator<T> >
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{
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static const std::size_t value = boost::move_detail::alignment_of<boost::move_detail::max_align_t>::value;
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};
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} //namespace pmr_dtl
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namespace pmr {
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//! An instance of resource_adaptor<Allocator> is an adaptor that wraps a memory_resource interface
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//! around Allocator. In order that resource_adaptor<X<T>> and resource_adaptor<X<U>> are the same
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//! type for any allocator template X and types T and U, resource_adaptor<Allocator> is rendered as
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//! an alias to this class template such that Allocator is rebound to a char value type in every
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//! specialization of the class template. The requirements on this class template are defined below.
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//! In addition to the Allocator requirements, the parameter to resource_adaptor shall meet
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//! the following additional requirements:
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//!
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//! - `typename allocator_traits<Allocator>:: pointer` shall be identical to
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//! `typename allocator_traits<Allocator>:: value_type*`.
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//!
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//! - `typename allocator_traits<Allocator>:: const_pointer` shall be identical to
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//! `typename allocator_traits<Allocator>:: value_type const*`.
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//!
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//! - `typename allocator_traits<Allocator>:: void_pointer` shall be identical to `void*`.
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//!
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//! - `typename allocator_traits<Allocator>:: const_void_pointer` shall be identical to `void const*`.
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template <class Allocator>
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class resource_adaptor_imp
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: public memory_resource
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#ifndef BOOST_CONTAINER_DOXYGEN_INVOKED
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, private ::boost::intrusive::detail::ebo_functor_holder<Allocator>
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#endif
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{
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#ifdef BOOST_CONTAINER_DOXYGEN_INVOKED
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Allocator m_alloc;
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#else
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BOOST_COPYABLE_AND_MOVABLE(resource_adaptor_imp)
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typedef ::boost::intrusive::detail::ebo_functor_holder<Allocator> ebo_alloc_t;
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void static_assert_if_not_char_allocator() const
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{
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//This class can only be used with allocators type char
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BOOST_STATIC_ASSERT((boost::container::dtl::is_same<typename Allocator::value_type, char>::value));
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}
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#endif
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public:
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typedef Allocator allocator_type;
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//! <b>Effects</b>: Default constructs
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//! m_alloc.
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resource_adaptor_imp()
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{ this->static_assert_if_not_char_allocator(); }
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//! <b>Effects</b>: Copy constructs
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//! m_alloc.
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resource_adaptor_imp(const resource_adaptor_imp &other)
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: ebo_alloc_t(other.ebo_alloc_t::get())
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{}
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//! <b>Effects</b>: Move constructs
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//! m_alloc.
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resource_adaptor_imp(BOOST_RV_REF(resource_adaptor_imp) other)
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: ebo_alloc_t(::boost::move(other.get()))
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{}
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//! <b>Effects</b>: Initializes m_alloc with
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//! a2.
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explicit resource_adaptor_imp(const Allocator& a2)
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: ebo_alloc_t(a2)
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{ this->static_assert_if_not_char_allocator(); }
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//! <b>Effects</b>: Initializes m_alloc with
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//! a2.
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explicit resource_adaptor_imp(BOOST_RV_REF(Allocator) a2)
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: ebo_alloc_t(::boost::move(a2))
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{ this->static_assert_if_not_char_allocator(); }
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//! <b>Effects</b>: Copy assigns
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//! m_alloc.
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resource_adaptor_imp& operator=(BOOST_COPY_ASSIGN_REF(resource_adaptor_imp) other)
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{ this->ebo_alloc_t::get() = other.ebo_alloc_t::get(); return *this; }
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//! <b>Effects</b>: Move assigns
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//! m_alloc.
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resource_adaptor_imp& operator=(BOOST_RV_REF(resource_adaptor_imp) other)
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{ this->ebo_alloc_t::get() = ::boost::move(other.ebo_alloc_t::get()); return *this; }
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//! <b>Effects</b>: Returns m_alloc.
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allocator_type &get_allocator()
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{ return this->ebo_alloc_t::get(); }
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//! <b>Effects</b>: Returns m_alloc.
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const allocator_type &get_allocator() const
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{ return this->ebo_alloc_t::get(); }
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protected:
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//! <b>Returns</b>: Allocated memory obtained by calling m_alloc.allocate. The size and alignment
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//! of the allocated memory shall meet the requirements for a class derived from memory_resource.
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virtual void* do_allocate(std::size_t bytes, std::size_t alignment)
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{
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if (alignment <= priv_guaranteed_allocator_alignment())
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return this->ebo_alloc_t::get().allocate(bytes);
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else
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return this->priv_aligned_alloc(bytes, alignment);
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}
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//! <b>Requires</b>: p was previously allocated using A.allocate, where A == m_alloc, and not
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//! subsequently deallocated.
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//!
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//! <b>Effects</b>: Returns memory to the allocator using m_alloc.deallocate().
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virtual void do_deallocate(void* p, std::size_t bytes, std::size_t alignment)
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{
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if (alignment <= priv_guaranteed_allocator_alignment())
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this->ebo_alloc_t::get().deallocate((char*)p, bytes);
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else
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this->priv_aligned_dealloc(p, bytes, alignment);
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}
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//! Let p be dynamic_cast<const resource_adaptor_imp*>(&other).
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//!
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//! <b>Returns</b>: false if p is null, otherwise the value of m_alloc == p->m_alloc.
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virtual bool do_is_equal(const memory_resource& other) const BOOST_NOEXCEPT
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{
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const resource_adaptor_imp* p = dynamic_cast<const resource_adaptor_imp*>(&other);
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return p && p->ebo_alloc_t::get() == this->ebo_alloc_t::get();
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}
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private:
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void * priv_aligned_alloc(std::size_t bytes, std::size_t alignment)
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{
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//Allocate space for requested bytes, plus alignment, plus bookeeping data
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void *const p = this->ebo_alloc_t::get().allocate(bytes + priv_extra_bytes_for_overalignment(alignment));
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if (0 != p) {
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//Obtain the aligned address after the bookeeping data
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void *const aligned_ptr = (void*)(((std::size_t)p + priv_extra_bytes_for_overalignment(alignment)) & ~(alignment - 1));
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//Store bookeeping data. Use memcpy as the underlying memory might be unaligned for
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//a pointer (e.g. 2 byte alignment in 32 bit, 4 byte alignment in 64 bit)
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std::memcpy(priv_bookeeping_addr_from_aligned_ptr(aligned_ptr), &p, sizeof(p));
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return aligned_ptr;
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}
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return 0;
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}
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void priv_aligned_dealloc(void *aligned_ptr, std::size_t bytes, std::size_t alignment)
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{
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//Obtain bookeeping data
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void *p;
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std::memcpy(&p, priv_bookeeping_addr_from_aligned_ptr(aligned_ptr), sizeof(p));
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std::size_t s = bytes + priv_extra_bytes_for_overalignment(alignment);
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this->ebo_alloc_t::get().deallocate((char*)p, s);
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}
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static BOOST_CONTAINER_FORCEINLINE void *priv_bookeeping_addr_from_aligned_ptr(void *aligned_ptr)
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{
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return reinterpret_cast<void*>(reinterpret_cast<std::size_t>(aligned_ptr) - sizeof(void*));
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}
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BOOST_CONTAINER_FORCEINLINE static std::size_t priv_extra_bytes_for_overalignment(std::size_t alignment)
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{
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return alignment - 1 + sizeof(void*);
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}
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BOOST_CONTAINER_FORCEINLINE static std::size_t priv_guaranteed_allocator_alignment()
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{
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return pmr_dtl::max_allocator_alignment<Allocator>::value;
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}
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};
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#if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES) || defined(BOOST_CONTAINER_DOXYGEN_INVOKED)
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//! `resource_adaptor<Allocator>` is rendered as an alias to resource_adaptor_imp class template
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//! such that Allocator is rebound to a char value type.
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template <class Allocator>
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using resource_adaptor = resource_adaptor_imp
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<typename allocator_traits<Allocator>::template rebind_alloc<char> >;
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#else
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template <class Allocator>
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class resource_adaptor
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: public resource_adaptor_imp
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<typename allocator_traits<Allocator>::template portable_rebind_alloc<char>::type>
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{
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typedef resource_adaptor_imp
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<typename allocator_traits<Allocator>::template portable_rebind_alloc<char>::type> base_t;
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BOOST_COPYABLE_AND_MOVABLE(resource_adaptor)
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public:
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resource_adaptor()
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: base_t()
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{}
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resource_adaptor(const resource_adaptor &other)
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: base_t(other)
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{}
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resource_adaptor(BOOST_RV_REF(resource_adaptor) other)
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: base_t(BOOST_MOVE_BASE(base_t, other))
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{}
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explicit resource_adaptor(const Allocator& a2)
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: base_t(a2)
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{}
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explicit resource_adaptor(BOOST_RV_REF(Allocator) a2)
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: base_t(::boost::move(a2))
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{}
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resource_adaptor& operator=(BOOST_COPY_ASSIGN_REF(resource_adaptor) other)
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{ return static_cast<resource_adaptor&>(this->base_t::operator=(other)); }
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resource_adaptor& operator=(BOOST_RV_REF(resource_adaptor) other)
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{ return static_cast<resource_adaptor&>(this->base_t::operator=(BOOST_MOVE_BASE(base_t, other))); }
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//get_allocator and protected functions are properly inherited
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};
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#endif
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} //namespace pmr {
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} //namespace container {
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} //namespace boost {
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#include <boost/container/detail/config_end.hpp>
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#endif //BOOST_CONTAINER_PMR_RESOURCE_ADAPTOR_HPP
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