Chris@102: /*
Chris@102:  (c) 2014 Glen Joseph Fernandes
Chris@102:  glenjofe at gmail dot com
Chris@102: 
Chris@102:  Distributed under the Boost Software
Chris@102:  License, Version 1.0.
Chris@102:  http://boost.org/LICENSE_1_0.txt
Chris@102: */
Chris@102: #ifndef BOOST_ALIGN_ALIGNED_ALLOCATOR_ADAPTOR_HPP
Chris@102: #define BOOST_ALIGN_ALIGNED_ALLOCATOR_ADAPTOR_HPP
Chris@102: 
Chris@102: #include <boost/config.hpp>
Chris@102: #include <boost/static_assert.hpp>
Chris@102: #include <boost/align/align.hpp>
Chris@102: #include <boost/align/aligned_allocator_adaptor_forward.hpp>
Chris@102: #include <boost/align/alignment_of.hpp>
Chris@102: #include <boost/align/detail/addressof.hpp>
Chris@102: #include <boost/align/detail/is_alignment_constant.hpp>
Chris@102: #include <boost/align/detail/max_align.hpp>
Chris@102: #include <new>
Chris@102: 
Chris@102: #if !defined(BOOST_NO_CXX11_ALLOCATOR)
Chris@102: #include <memory>
Chris@102: #endif
Chris@102: 
Chris@102: #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
Chris@102: #include <utility>
Chris@102: #endif
Chris@102: 
Chris@102: namespace boost {
Chris@102:     namespace alignment {
Chris@102:         template<class Allocator, std::size_t Alignment>
Chris@102:         class aligned_allocator_adaptor
Chris@102:             : public Allocator {
Chris@102:             BOOST_STATIC_ASSERT(detail::
Chris@102:                 is_alignment_constant<Alignment>::value);
Chris@102: 
Chris@102: #if !defined(BOOST_NO_CXX11_ALLOCATOR)
Chris@102:             typedef std::allocator_traits<Allocator> Traits;
Chris@102: 
Chris@102:             typedef typename Traits::
Chris@102:                 template rebind_alloc<char> CharAlloc;
Chris@102: 
Chris@102:             typedef typename Traits::
Chris@102:                 template rebind_traits<char> CharTraits;
Chris@102: 
Chris@102:             typedef typename CharTraits::pointer CharPtr;
Chris@102: #else
Chris@102:             typedef typename Allocator::
Chris@102:                 template rebind<char>::other CharAlloc;
Chris@102: 
Chris@102:             typedef typename CharAlloc::pointer CharPtr;
Chris@102: #endif
Chris@102: 
Chris@102:         public:
Chris@102: #if !defined(BOOST_NO_CXX11_ALLOCATOR)
Chris@102:             typedef typename Traits::value_type value_type;
Chris@102:             typedef typename Traits::size_type size_type;
Chris@102: #else
Chris@102:             typedef typename Allocator::value_type value_type;
Chris@102:             typedef typename Allocator::size_type size_type;
Chris@102: #endif
Chris@102: 
Chris@102:             typedef value_type* pointer;
Chris@102:             typedef const value_type* const_pointer;
Chris@102:             typedef void* void_pointer;
Chris@102:             typedef const void* const_void_pointer;
Chris@102:             typedef std::ptrdiff_t difference_type;
Chris@102: 
Chris@102:         private:
Chris@102:             typedef detail::max_align<Alignment,
Chris@102:                 detail::max_align<alignment_of<value_type>::value,
Chris@102:                     alignment_of<CharPtr>::value>::value> MaxAlign;
Chris@102: 
Chris@102:         public:
Chris@102:             template<class U>
Chris@102:             struct rebind {
Chris@102: #if !defined(BOOST_NO_CXX11_ALLOCATOR)
Chris@102:                 typedef aligned_allocator_adaptor<typename Traits::
Chris@102:                     template rebind_alloc<U>, Alignment> other;
Chris@102: #else
Chris@102:                 typedef aligned_allocator_adaptor<typename Allocator::
Chris@102:                     template rebind<U>::other, Alignment> other;
Chris@102: #endif
Chris@102:             };
Chris@102: 
Chris@102: #if !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS)
Chris@102:             aligned_allocator_adaptor() = default;
Chris@102: #else
Chris@102:             aligned_allocator_adaptor()
Chris@102:                 : Allocator() {
Chris@102:             }
Chris@102: #endif
Chris@102: 
Chris@102: #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
Chris@102:             template<class A>
Chris@102:             explicit aligned_allocator_adaptor(A&& alloc)
Chris@102:                 BOOST_NOEXCEPT
Chris@102:                 : Allocator(std::forward<A>(alloc)) {
Chris@102:             }
Chris@102: #else
Chris@102:             template<class A>
Chris@102:             explicit aligned_allocator_adaptor(const A& alloc)
Chris@102:                 BOOST_NOEXCEPT
Chris@102:                 : Allocator(alloc) {
Chris@102:             }
Chris@102: #endif
Chris@102: 
Chris@102:             template<class U>
Chris@102:             aligned_allocator_adaptor(const
Chris@102:                 aligned_allocator_adaptor<U, Alignment>& other)
Chris@102:                 BOOST_NOEXCEPT
Chris@102:                 : Allocator(other.base()) {
Chris@102:             }
Chris@102: 
Chris@102:             Allocator& base()
Chris@102:                 BOOST_NOEXCEPT {
Chris@102:                 return static_cast<Allocator&>(*this);
Chris@102:             }
Chris@102: 
Chris@102:             const Allocator& base() const
Chris@102:                 BOOST_NOEXCEPT {
Chris@102:                 return static_cast<const Allocator&>(*this);
Chris@102:             }
Chris@102: 
Chris@102:             pointer allocate(size_type size) {
Chris@102:                 std::size_t n1 = size * sizeof(value_type);
Chris@102:                 std::size_t n2 = n1 + MaxAlign::value - 1;
Chris@102:                 CharAlloc a(base());
Chris@102:                 CharPtr p1 = a.allocate(sizeof p1 + n2);
Chris@102:                 void* p2 = detail::addressof(*p1) + sizeof p1;
Chris@102:                 (void)align(MaxAlign::value, n1, p2, n2);
Chris@102:                 void* p3 = static_cast<CharPtr*>(p2) - 1;
Chris@102:                 ::new(p3) CharPtr(p1);
Chris@102:                 return static_cast<pointer>(p2);
Chris@102:             }
Chris@102: 
Chris@102:             pointer allocate(size_type size, const_void_pointer hint) {
Chris@102:                 std::size_t n1 = size * sizeof(value_type);
Chris@102:                 std::size_t n2 = n1 + MaxAlign::value - 1;
Chris@102:                 CharPtr h = CharPtr();
Chris@102:                 if (hint) {
Chris@102:                     h = *(static_cast<const CharPtr*>(hint) - 1);
Chris@102:                 }
Chris@102:                 CharAlloc a(base());
Chris@102: #if !defined(BOOST_NO_CXX11_ALLOCATOR)
Chris@102:                 CharPtr p1 = CharTraits::allocate(a, sizeof p1 +
Chris@102:                     n2, h);
Chris@102: #else
Chris@102:                 CharPtr p1 = a.allocate(sizeof p1 + n2, h);
Chris@102: #endif
Chris@102:                 void* p2 = detail::addressof(*p1) + sizeof p1;
Chris@102:                 (void)align(MaxAlign::value, n1, p2, n2);
Chris@102:                 void* p3 = static_cast<CharPtr*>(p2) - 1;
Chris@102:                 ::new(p3) CharPtr(p1);
Chris@102:                 return static_cast<pointer>(p2);
Chris@102:             }
Chris@102: 
Chris@102:             void deallocate(pointer ptr, size_type size) {
Chris@102:                 CharPtr* p1 = reinterpret_cast<CharPtr*>(ptr) - 1;
Chris@102:                 CharPtr p2 = *p1;
Chris@102:                 p1->~CharPtr();
Chris@102:                 CharAlloc a(base());
Chris@102:                 a.deallocate(p2, size * sizeof(value_type) +
Chris@102:                     MaxAlign::value + sizeof p2);
Chris@102:             }
Chris@102:         };
Chris@102: 
Chris@102:         template<class A1, class A2, std::size_t Alignment>
Chris@102:         inline bool operator==(const aligned_allocator_adaptor<A1,
Chris@102:             Alignment>& a, const aligned_allocator_adaptor<A2,
Chris@102:             Alignment>& b) BOOST_NOEXCEPT
Chris@102:         {
Chris@102:             return a.base() == b.base();
Chris@102:         }
Chris@102: 
Chris@102:         template<class A1, class A2, std::size_t Alignment>
Chris@102:         inline bool operator!=(const aligned_allocator_adaptor<A1,
Chris@102:             Alignment>& a, const aligned_allocator_adaptor<A2,
Chris@102:             Alignment>& b) BOOST_NOEXCEPT
Chris@102:         {
Chris@102:             return !(a == b);
Chris@102:         }
Chris@102:     }
Chris@102: }
Chris@102: 
Chris@102: #endif