1 //////////////////////////////////////////////////////////////////////////////
2 //
3 // (C) Copyright Ion Gaztanaga 2015-2015. Distributed under the Boost
4 // Software License, Version 1.0. (See accompanying file
5 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 //
7 // See http://www.boost.org/libs/container for documentation.
8 //
9 //////////////////////////////////////////////////////////////////////////////
10
11 #ifndef BOOST_CONTAINER_PMR_MEMORY_RESOURCE_HPP
12 #define BOOST_CONTAINER_PMR_MEMORY_RESOURCE_HPP
13
14 #if defined (_MSC_VER)
15 # pragma once
16 #endif
17
18 #include <boost/container/detail/config_begin.hpp>
19 #include <boost/container/detail/workaround.hpp>
20 #include <boost/container/container_fwd.hpp>
21 #include <boost/move/detail/type_traits.hpp>
22 #include <cstddef>
23
24 namespace boost {
25 namespace container {
26 namespace pmr {
27
28 //! The memory_resource class is an abstract interface to an
29 //! unbounded set of classes encapsulating memory resources.
30 class BOOST_CONTAINER_DECL memory_resource
31 {
32 public:
33 // For exposition only
34 static BOOST_CONSTEXPR_OR_CONST std::size_t max_align =
35 boost::move_detail::alignment_of<boost::move_detail::max_align_t>::value;
36
37 //! <b>Effects</b>: Destroys
38 //! this memory_resource.
~memory_resource()39 virtual ~memory_resource(){}
40
41 //! <b>Effects</b>: Equivalent to
42 //! `return do_allocate(bytes, alignment);`
allocate(std::size_t bytes,std::size_t alignment=max_align)43 void* allocate(std::size_t bytes, std::size_t alignment = max_align)
44 { return this->do_allocate(bytes, alignment); }
45
46 //! <b>Effects</b>: Equivalent to
47 //! `return do_deallocate(bytes, alignment);`
deallocate(void * p,std::size_t bytes,std::size_t alignment=max_align)48 void deallocate(void* p, std::size_t bytes, std::size_t alignment = max_align)
49 { return this->do_deallocate(p, bytes, alignment); }
50
51 //! <b>Effects</b>: Equivalent to
52 //! `return return do_is_equal(other);`
is_equal(const memory_resource & other) const53 bool is_equal(const memory_resource& other) const BOOST_NOEXCEPT
54 { return this->do_is_equal(other); }
55
56 #if !defined(BOOST_EMBTC)
57
58 //! <b>Returns</b>:
59 //! `&a == &b || a.is_equal(b)`.
operator ==(const memory_resource & a,const memory_resource & b)60 friend bool operator==(const memory_resource& a, const memory_resource& b) BOOST_NOEXCEPT
61 { return &a == &b || a.is_equal(b); }
62
63 //! <b>Returns</b>:
64 //! !(a == b).
operator !=(const memory_resource & a,const memory_resource & b)65 friend bool operator!=(const memory_resource& a, const memory_resource& b) BOOST_NOEXCEPT
66 { return !(a == b); }
67
68 #else
69
70 //! <b>Returns</b>:
71 //! `&a == &b || a.is_equal(b)`.
72 friend bool operator==(const memory_resource& a, const memory_resource& b) BOOST_NOEXCEPT;
73
74 //! <b>Returns</b>:
75 //! !(a == b).
76 friend bool operator!=(const memory_resource& a, const memory_resource& b) BOOST_NOEXCEPT;
77
78 #endif
79
80 protected:
81 //! <b>Requires</b>: Alignment shall be a power of two.
82 //!
83 //! <b>Returns</b>: A derived class shall implement this function to return a pointer
84 //! to allocated storage with a size of at least bytes. The returned storage is
85 //! aligned to the specified alignment, if such alignment is supported; otherwise
86 //! it is aligned to max_align.
87 //!
88 //! <b>Throws</b>: A derived class implementation shall throw an appropriate exception if
89 //! it is unable to allocate memory with the requested size and alignment.
90 virtual void* do_allocate(std::size_t bytes, std::size_t alignment) = 0;
91
92 //! <b>Requires</b>: p shall have been returned from a prior call to
93 //! `allocate(bytes, alignment)` on a memory resource equal to *this, and the storage
94 //! at p shall not yet have been deallocated.
95 //!
96 //! <b>Effects</b>: A derived class shall implement this function to dispose of allocated storage.
97 //!
98 //! <b>Throws</b>: Nothing.
99 virtual void do_deallocate(void* p, std::size_t bytes, std::size_t alignment) = 0;
100
101 //! <b>Returns</b>: A derived class shall implement this function to return true if memory
102 //! allocated from this can be deallocated from other and vice-versa; otherwise it shall
103 //! return false. <i>[Note: The most-derived type of other might not match the type of this.
104 //! For a derived class, D, a typical implementation of this function will compute
105 //! `dynamic_cast<const D*>(&other)` and go no further (i.e., return false)
106 //! if it returns nullptr. - end note]</i>.
107 virtual bool do_is_equal(const memory_resource& other) const BOOST_NOEXCEPT = 0;
108 };
109
110 #if defined(BOOST_EMBTC)
111
112 //! <b>Returns</b>:
113 //! `&a == &b || a.is_equal(b)`.
operator ==(const memory_resource & a,const memory_resource & b)114 inline bool operator==(const memory_resource& a, const memory_resource& b) BOOST_NOEXCEPT
115 { return &a == &b || a.is_equal(b); }
116
117 //! <b>Returns</b>:
118 //! !(a == b).
operator !=(const memory_resource & a,const memory_resource & b)119 inline bool operator!=(const memory_resource& a, const memory_resource& b) BOOST_NOEXCEPT
120 { return !(a == b); }
121
122 #endif
123
124 } //namespace pmr {
125 } //namespace container {
126 } //namespace boost {
127
128 #include <boost/container/detail/config_end.hpp>
129
130 #endif //BOOST_CONTAINER_PMR_MEMORY_RESOURCE_HPP
131