2 Copyright 2014-2016 Glen Joseph Fernandes
5 Distributed under the Boost Software License, Version 1.0.
6 (http://www.boost.org/LICENSE_1_0.txt)
8 #ifndef BOOST_ALIGN_ALIGNED_ALLOCATOR_ADAPTOR_HPP
9 #define BOOST_ALIGN_ALIGNED_ALLOCATOR_ADAPTOR_HPP
11 #include <boost/align/detail/is_alignment_constant.hpp>
12 #include <boost/align/detail/max_align.hpp>
13 #include <boost/align/detail/max_size.hpp>
14 #include <boost/align/align.hpp>
15 #include <boost/align/aligned_allocator_adaptor_forward.hpp>
16 #include <boost/align/alignment_of.hpp>
17 #include <boost/core/pointer_traits.hpp>
18 #include <boost/static_assert.hpp>
21 #if !defined(BOOST_NO_CXX11_ALLOCATOR)
25 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
32 template<class Allocator, std::size_t Alignment>
33 class aligned_allocator_adaptor
35 BOOST_STATIC_ASSERT(detail::is_alignment_constant<Alignment>::value);
37 #if !defined(BOOST_NO_CXX11_ALLOCATOR)
38 typedef std::allocator_traits<Allocator> traits;
39 typedef typename traits::template rebind_alloc<char> char_alloc;
40 typedef typename traits::template rebind_traits<char> char_traits;
41 typedef typename char_traits::pointer char_ptr;
43 typedef typename Allocator::template rebind<char>::other char_alloc;
44 typedef typename char_alloc::pointer char_ptr;
48 typedef typename Allocator::value_type value_type;
49 typedef value_type* pointer;
50 typedef const value_type* const_pointer;
51 typedef void* void_pointer;
52 typedef const void* const_void_pointer;
53 typedef std::size_t size_type;
54 typedef std::ptrdiff_t difference_type;
58 min_align = detail::max_size<Alignment,
59 detail::max_align<value_type, char_ptr>::value>::value
65 #if !defined(BOOST_NO_CXX11_ALLOCATOR)
66 typedef aligned_allocator_adaptor<typename traits::template
67 rebind_alloc<U>, Alignment> other;
69 typedef aligned_allocator_adaptor<typename Allocator::template
70 rebind<U>::other, Alignment> other;
74 #if !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS)
75 aligned_allocator_adaptor() = default;
77 aligned_allocator_adaptor()
81 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
83 explicit aligned_allocator_adaptor(A&& alloc) BOOST_NOEXCEPT
84 : Allocator(std::forward<A>(alloc)) { }
87 explicit aligned_allocator_adaptor(const A& alloc) BOOST_NOEXCEPT
88 : Allocator(alloc) { }
92 aligned_allocator_adaptor(const aligned_allocator_adaptor<U,
93 Alignment>& other) BOOST_NOEXCEPT
94 : Allocator(other.base()) { }
96 Allocator& base() BOOST_NOEXCEPT {
97 return static_cast<Allocator&>(*this);
100 const Allocator& base() const BOOST_NOEXCEPT {
101 return static_cast<const Allocator&>(*this);
104 pointer allocate(size_type size) {
105 std::size_t s = size * sizeof(value_type);
106 std::size_t n = s + min_align - 1;
107 char_alloc a(base());
108 char_ptr p = a.allocate(sizeof p + n);
109 void* r = boost::pointer_traits<char_ptr>::to_address(p) + sizeof p;
110 (void)align(min_align, s, r, n);
111 ::new(static_cast<void*>(static_cast<char_ptr*>(r) - 1)) char_ptr(p);
112 return static_cast<pointer>(r);
115 pointer allocate(size_type size, const_void_pointer hint) {
116 std::size_t s = size * sizeof(value_type);
117 std::size_t n = s + min_align - 1;
118 char_ptr h = char_ptr();
120 h = *(static_cast<const char_ptr*>(hint) - 1);
122 char_alloc a(base());
123 #if !defined(BOOST_NO_CXX11_ALLOCATOR)
124 char_ptr p = char_traits::allocate(a, sizeof p + n, h);
126 char_ptr p = a.allocate(sizeof p + n, h);
128 void* r = boost::pointer_traits<char_ptr>::to_address(p) + sizeof p;
129 (void)align(min_align, s, r, n);
130 ::new(static_cast<void*>(static_cast<char_ptr*>(r) - 1)) char_ptr(p);
131 return static_cast<pointer>(r);
134 void deallocate(pointer ptr, size_type size) {
135 char_ptr* p = reinterpret_cast<char_ptr*>(ptr) - 1;
138 char_alloc a(base());
139 a.deallocate(r, sizeof r + size * sizeof(value_type) + min_align - 1);
143 template<class A, class B, std::size_t Alignment>
145 operator==(const aligned_allocator_adaptor<A, Alignment>& a,
146 const aligned_allocator_adaptor<B, Alignment>& b) BOOST_NOEXCEPT
148 return a.base() == b.base();
151 template<class A, class B, std::size_t Alignment>
153 operator!=(const aligned_allocator_adaptor<A, Alignment>& a,
154 const aligned_allocator_adaptor<B, Alignment>& b) BOOST_NOEXCEPT