ut::detail::Aligned_alloc_metadata< Meta_1_type, Meta_2_type > Struct Template Reference

Memory layout representation of metadata segment guaranteed by the inner workings of Aligned_alloc_impl. More...

#include <aligned_alloc.h>

Public Types
using	meta_1_t = Meta_1_type
	Convenience types that we will be using to serialize necessary details into the metadata segment. More...
using	meta_2_t = Meta_2_type
using	unaligned_meta_2_t = meta_2_t

Static Public Member Functions
static void	meta_1 (Aligned_alloc_impl::data_segment_ptr data, std::size_t meta_1_v) noexcept
	Bail out if we cannot fit the requested data size. More...
static void	meta_2 (Aligned_alloc_impl::data_segment_ptr data, std::size_t meta_2_v) noexcept
	Helper function which stores user-provided detail into the META_2 field. More...
static meta_1_t	meta_1 (Aligned_alloc_impl::data_segment_ptr data) noexcept
	Helper function which recovers the information user previously stored in META_1 field. More...
static meta_2_t	meta_2 (Aligned_alloc_impl::data_segment_ptr data) noexcept
	Helper function which recovers the information user previously stored in META_2 field. More...

Static Public Attributes
static constexpr auto	allocator_metadata_size
	Metadata size. More...
static constexpr auto	max_metadata_size = Aligned_alloc_impl::metadata_size
	Max metadata size. More...

Static Private Member Functions
static meta_1_t *	ptr_to_meta_1 (Aligned_alloc_impl::data_segment_ptr data) noexcept
	Helper accessor function to metadata (offset). More...
static unaligned_meta_2_t *	ptr_to_meta_2 (Aligned_alloc_impl::data_segment_ptr data) noexcept
	Helper accessor function to metadata (data length). More...

Detailed Description

template<typename Meta_1_type, typename Meta_2_type>
struct ut::detail::Aligned_alloc_metadata< Meta_1_type, Meta_2_type >

Memory layout representation of metadata segment guaranteed by the inner workings of Aligned_alloc_impl.

---

| VARLEN | ALIGNED-ALLOC-META | ... DATA ... |

^ ^ | | | | | ptr returned by Aligned_alloc_impl

|

| META_2 | META_1 |

\ \ 0 \ \ alignof(max_align_t) - 1

VARLEN and ALIGNED-ALLOC-META are direct byproduct of Aligned_alloc_impl layout and guarantees.

VARLEN is the leftover variable-length segment that specialized implementations can further make use of by deducing its size from returned offset. Not used by this implementation.

ALIGNED-ALLOC-META is the segment which this abstraction is about. It can hold up to sizeof(META_1) + sizeof(META_2) bytes which is, due to Aligned_alloc_impl guarantees, at most alignof(max_align_t) bytes large. Providing larger data than supported is not possible and it is guarded through the means of static_assert. META_1 and META_2 fields can be arbitrarily sized meaning that they can even be of different sizes each.

DATA is an actual segment which will keep the user data.

Member Typedef Documentation

meta_1_t

template<typename Meta_1_type , typename Meta_2_type >

using ut::detail::Aligned_alloc_metadata< Meta_1_type, Meta_2_type >::meta_1_t = Meta_1_type

Convenience types that we will be using to serialize necessary details into the metadata segment.

meta_2_t

template<typename Meta_1_type , typename Meta_2_type >

using ut::detail::Aligned_alloc_metadata< Meta_1_type, Meta_2_type >::meta_2_t = Meta_2_type

unaligned_meta_2_t

template<typename Meta_1_type , typename Meta_2_type >

using ut::detail::Aligned_alloc_metadata< Meta_1_type, Meta_2_type >::unaligned_meta_2_t = meta_2_t

Member Function Documentation

meta_1() [1/2]

template<typename Meta_1_type , typename Meta_2_type >

static meta_1_t ut::detail::Aligned_alloc_metadata< Meta_1_type, Meta_2_type >::meta_1 ( Aligned_alloc_impl::data_segment_ptr  data )

inlinestaticnoexcept

Helper function which recovers the information user previously stored in META_1 field.

meta_1() [2/2]

template<typename Meta_1_type , typename Meta_2_type >

static void ut::detail::Aligned_alloc_metadata< Meta_1_type, Meta_2_type >::meta_1 ( Aligned_alloc_impl::data_segment_ptr  data, std::size_t  meta_1_v  )

inlinestaticnoexcept

Bail out if we cannot fit the requested data size.

Helper function which stores user-provided detail into the META_1 field.

meta_2() [1/2]

template<typename Meta_1_type , typename Meta_2_type >

static meta_2_t ut::detail::Aligned_alloc_metadata< Meta_1_type, Meta_2_type >::meta_2 ( Aligned_alloc_impl::data_segment_ptr  data )

inlinestaticnoexcept

Helper function which recovers the information user previously stored in META_2 field.

meta_2() [2/2]

template<typename Meta_1_type , typename Meta_2_type >

static void ut::detail::Aligned_alloc_metadata< Meta_1_type, Meta_2_type >::meta_2 ( Aligned_alloc_impl::data_segment_ptr  data, std::size_t  meta_2_v  )

inlinestaticnoexcept

Helper function which stores user-provided detail into the META_2 field.

ptr_to_meta_1()

template<typename Meta_1_type , typename Meta_2_type >

static meta_1_t * ut::detail::Aligned_alloc_metadata< Meta_1_type, Meta_2_type >::ptr_to_meta_1 ( Aligned_alloc_impl::data_segment_ptr  data )

inlinestaticprivatenoexcept

Helper accessor function to metadata (offset).

ptr_to_meta_2()

template<typename Meta_1_type , typename Meta_2_type >

static unaligned_meta_2_t * ut::detail::Aligned_alloc_metadata< Meta_1_type, Meta_2_type >::ptr_to_meta_2 ( Aligned_alloc_impl::data_segment_ptr  data )

inlinestaticprivatenoexcept

Helper accessor function to metadata (data length).

Member Data Documentation

allocator_metadata_size

template<typename Meta_1_type , typename Meta_2_type >

constexpr auto ut::detail::Aligned_alloc_metadata< Meta_1_type, Meta_2_type >::allocator_metadata_size

staticconstexpr

Initial value:

=
      sizeof(meta_1_t) + sizeof(meta_2_t)

Metadata size.

max_metadata_size

template<typename Meta_1_type , typename Meta_2_type >

constexpr auto ut::detail::Aligned_alloc_metadata< Meta_1_type, Meta_2_type >::max_metadata_size = Aligned_alloc_impl::metadata_size

staticconstexpr

Max metadata size.

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The documentation for this struct was generated from the following file:

• storage/innobase/include/detail/ut/aligned_alloc.h