libcxx/include/__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 <__config>
  13 #include <__cstddef/max_align_t.h>
  14 #include <__cstddef/size_t.h>
  15 #include <__fwd/memory_resource.h>
  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   [[nodiscard]] [[using __gnu__: __returns_nonnull__, __alloc_size__(2), __alloc_align__(3)]]
  36   _LIBCPP_HIDE_FROM_ABI void* allocate(size_t __bytes, size_t __align = __max_align) {
  37     return do_allocate(__bytes, __align);
  38   }
  39
  40   [[__gnu__::__nonnull__]] _LIBCPP_HIDE_FROM_ABI void
  41   deallocate(void* __p, size_t __bytes, size_t __align = __max_align) {
  42     do_deallocate(__p, __bytes, __align);
  43   }
  44
  45   _LIBCPP_HIDE_FROM_ABI bool is_equal(const memory_resource& __other) const noexcept { return do_is_equal(__other); }
  46
  47 private:
  48   virtual void* do_allocate(size_t, size_t)                       = 0;
  49   virtual void do_deallocate(void*, size_t, size_t)               = 0;
  50   virtual bool do_is_equal(memory_resource const&) const noexcept = 0;
  51 };
  52
  53 // [mem.res.eq]
  54
  55 inline _LIBCPP_AVAILABILITY_PMR _LIBCPP_HIDE_FROM_ABI bool
  56 operator==(const memory_resource& __lhs, const memory_resource& __rhs) noexcept {
  57   return &__lhs == &__rhs || __lhs.is_equal(__rhs);
  58 }
  59
  60 #  if _LIBCPP_STD_VER <= 17
  61
  62 inline _LIBCPP_AVAILABILITY_PMR _LIBCPP_HIDE_FROM_ABI bool
  63 operator!=(const memory_resource& __lhs, const memory_resource& __rhs) noexcept {
  64   return !(__lhs == __rhs);
  65 }
  66
  67 #  endif
  68
  69 // [mem.res.global]
  70
  71 [[__gnu__::__returns_nonnull__]] _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource*
  72 get_default_resource() noexcept;
  73
  74 [[__gnu__::__returns_nonnull__]] _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource*
  75 set_default_resource(memory_resource*) noexcept;
  76
  77 [[using __gnu__: __returns_nonnull__, __const__]] _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource*
  78 new_delete_resource() noexcept;
  79
  80 [[using __gnu__: __returns_nonnull__, __const__]] _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource*
  81 null_memory_resource() noexcept;
  82
  83 } // namespace pmr
  84
  85 _LIBCPP_END_NAMESPACE_STD
  86
  87 #endif // _LIBCPP_STD_VER >= 17
  88
  89 #endif // _LIBCPP___MEMORY_RESOURCE_MEMORY_RESOURCE_H