xref: /freebsd/contrib/llvm-project/libcxx/include/__memory_resource/memory_resource.h (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
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 <__config>
13 #include <__fwd/memory_resource.h>
14 #include <cstddef>
15 
16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17 #  pragma GCC system_header
18 #endif
19 
20 #if _LIBCPP_STD_VER >= 17
21 
22 _LIBCPP_BEGIN_NAMESPACE_STD
23 
24 namespace pmr {
25 
26 // [mem.res.class]
27 
28 class _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource {
29   static const size_t __max_align = alignof(max_align_t);
30 
31 public:
32   virtual ~memory_resource();
33 
34   [[nodiscard]] [[using __gnu__: __returns_nonnull__, __alloc_size__(2), __alloc_align__(3)]]
35   _LIBCPP_HIDE_FROM_ABI void* allocate(size_t __bytes, size_t __align = __max_align) {
36     return do_allocate(__bytes, __align);
37   }
38 
39   [[__gnu__::__nonnull__]] _LIBCPP_HIDE_FROM_ABI void
40   deallocate(void* __p, size_t __bytes, size_t __align = __max_align) {
41     do_deallocate(__p, __bytes, __align);
42   }
43 
is_equal(const memory_resource & __other)44   _LIBCPP_HIDE_FROM_ABI bool is_equal(const memory_resource& __other) const noexcept { return do_is_equal(__other); }
45 
46 private:
47   virtual void* do_allocate(size_t, size_t)                       = 0;
48   virtual void do_deallocate(void*, size_t, size_t)               = 0;
49   virtual bool do_is_equal(memory_resource const&) const noexcept = 0;
50 };
51 
52 // [mem.res.eq]
53 
54 inline _LIBCPP_AVAILABILITY_PMR _LIBCPP_HIDE_FROM_ABI bool
55 operator==(const memory_resource& __lhs, const memory_resource& __rhs) noexcept {
56   return &__lhs == &__rhs || __lhs.is_equal(__rhs);
57 }
58 
59 #  if _LIBCPP_STD_VER <= 17
60 
61 inline _LIBCPP_AVAILABILITY_PMR _LIBCPP_HIDE_FROM_ABI bool
62 operator!=(const memory_resource& __lhs, const memory_resource& __rhs) noexcept {
63   return !(__lhs == __rhs);
64 }
65 
66 #  endif
67 
68 // [mem.res.global]
69 
70 [[__gnu__::__returns_nonnull__]] _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource*
71 get_default_resource() noexcept;
72 
73 [[__gnu__::__returns_nonnull__]] _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource*
74 set_default_resource(memory_resource*) noexcept;
75 
76 [[using __gnu__: __returns_nonnull__, __const__]] _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource*
77 new_delete_resource() noexcept;
78 
79 [[using __gnu__: __returns_nonnull__, __const__]] _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource*
80 null_memory_resource() noexcept;
81 
82 } // namespace pmr
83 
84 _LIBCPP_END_NAMESPACE_STD
85 
86 #endif // _LIBCPP_STD_VER >= 17
87 
88 #endif // _LIBCPP___MEMORY_RESOURCE_MEMORY_RESOURCE_H
89