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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 <cstddef>
14 
15 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
16 #  pragma GCC system_header
17 #endif
18 
19 #if _LIBCPP_STD_VER >= 17
20 
21 _LIBCPP_BEGIN_NAMESPACE_STD
22 
23 namespace pmr {
24 
25 // [mem.res.class]
26 
27 class _LIBCPP_TYPE_VIS memory_resource {
28   static const size_t __max_align = alignof(max_align_t);
29 
30 public:
31   virtual ~memory_resource();
32 
33   _LIBCPP_NODISCARD_AFTER_CXX17
34   [[using __gnu__: __returns_nonnull__, __alloc_size__(2), __alloc_align__(3)]] _LIBCPP_HIDE_FROM_ABI void*
35   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_HIDE_FROM_ABI bool operator==(const memory_resource& __lhs, const memory_resource& __rhs) noexcept {
55   return &__lhs == &__rhs || __lhs.is_equal(__rhs);
56 }
57 
58 inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const memory_resource& __lhs, const memory_resource& __rhs) noexcept {
59   return !(__lhs == __rhs);
60 }
61 
62 // [mem.res.global]
63 
64 [[__gnu__::__returns_nonnull__]] _LIBCPP_FUNC_VIS memory_resource* get_default_resource() noexcept;
65 [[__gnu__::__returns_nonnull__]] _LIBCPP_FUNC_VIS memory_resource* set_default_resource(memory_resource*) noexcept;
66 [[using __gnu__: __returns_nonnull__, __const__]] _LIBCPP_FUNC_VIS memory_resource* new_delete_resource() noexcept;
67 [[using __gnu__: __returns_nonnull__, __const__]] _LIBCPP_FUNC_VIS memory_resource* null_memory_resource() noexcept;
68 
69 } // namespace pmr
70 
71 _LIBCPP_END_NAMESPACE_STD
72 
73 #endif // _LIBCPP_STD_VER >= 17
74 
75 #endif // _LIBCPP___MEMORY_RESOURCE_MEMORY_RESOURCE_H
76