1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef _LIBCPP___MEMORY_RESOURCE_MEMORY_RESOURCE_H
10 #define _LIBCPP___MEMORY_RESOURCE_MEMORY_RESOURCE_H
11 
12 #include <__availability>
13 #include <__config>
14 #include <__fwd/memory_resource.h>
15 #include <cstddef>
16 
17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18 #  pragma GCC system_header
19 #endif
20 
21 #if _LIBCPP_STD_VER >= 17
22 
23 _LIBCPP_BEGIN_NAMESPACE_STD
24 
25 namespace pmr {
26 
27 // [mem.res.class]
28 
29 class _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource {
30   static const size_t __max_align = alignof(max_align_t);
31 
32 public:
33   virtual ~memory_resource();
34 
35   _LIBCPP_NODISCARD_AFTER_CXX17
36   [[using __gnu__: __returns_nonnull__, __alloc_size__(2), __alloc_align__(3)]] _LIBCPP_HIDE_FROM_ABI void*
37   allocate(size_t __bytes, size_t __align = __max_align) {
38     return do_allocate(__bytes, __align);
39   }
40 
41   [[__gnu__::__nonnull__]] _LIBCPP_HIDE_FROM_ABI void
42   deallocate(void* __p, size_t __bytes, size_t __align = __max_align) {
43     do_deallocate(__p, __bytes, __align);
44   }
45 
46   _LIBCPP_HIDE_FROM_ABI bool is_equal(const memory_resource& __other) const noexcept { return do_is_equal(__other); }
47 
48 private:
49   virtual void* do_allocate(size_t, size_t)                       = 0;
50   virtual void do_deallocate(void*, size_t, size_t)               = 0;
51   virtual bool do_is_equal(memory_resource const&) const noexcept = 0;
52 };
53 
54 // [mem.res.eq]
55 
56 inline _LIBCPP_AVAILABILITY_PMR _LIBCPP_HIDE_FROM_ABI bool
57 operator==(const memory_resource& __lhs, const memory_resource& __rhs) noexcept {
58   return &__lhs == &__rhs || __lhs.is_equal(__rhs);
59 }
60 
61 #  if _LIBCPP_STD_VER <= 17
62 
63 inline _LIBCPP_AVAILABILITY_PMR _LIBCPP_HIDE_FROM_ABI bool
64 operator!=(const memory_resource& __lhs, const memory_resource& __rhs) noexcept {
65   return !(__lhs == __rhs);
66 }
67 
68 #  endif
69 
70 // [mem.res.global]
71 
72 [[__gnu__::__returns_nonnull__]] _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource*
73 get_default_resource() noexcept;
74 
75 [[__gnu__::__returns_nonnull__]] _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource*
76 set_default_resource(memory_resource*) noexcept;
77 
78 [[using __gnu__: __returns_nonnull__, __const__]] _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource*
79 new_delete_resource() noexcept;
80 
81 [[using __gnu__: __returns_nonnull__, __const__]] _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource*
82 null_memory_resource() noexcept;
83 
84 } // namespace pmr
85 
86 _LIBCPP_END_NAMESPACE_STD
87 
88 #endif // _LIBCPP_STD_VER >= 17
89 
90 #endif // _LIBCPP___MEMORY_RESOURCE_MEMORY_RESOURCE_H
91