libcxx/include/__cxx03/__memory_resource/memory_resource.h

   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 <__cxx03/__config>
  13 #include <__cxx03/__fwd/memory_resource.h>
  14 #include <__cxx03/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
  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