Overview

Allocator interface that specializes in producing v1-compatible chunks.

This allocator does not store allocation inline with allocated memory, like a BlockAllocator. Instead, it has a reference to a second allocator that it can use provide space for metadata tracking which regions of an overall memory arena are allocated. This allows the allocator to fully allocate the arena without using any of it for overhead.

The details of how the second allocator is used are implemented by the derived classes.

Inheritance diagram for pw::multibuf::v1_adapter::internal::ChunkAllocator:

Public Member Functions
constexpr Allocator &	metadata_allocator () const

constexpr size_t	alignment () const

constexpr size_t	available () const

constexpr ByteSpan	buffer () const

std::optional< OwnedChunk >	AllocateChunk (size_t min_size, size_t desired_size)

std::optional< OwnedChunk >	AllocateChunk (size_t size)

Public Member Functions inherited from pw::Allocator
void *	Allocate (Layout layout)

template<typename T , int &... kExplicitGuard, std::enable_if_t<!std::is_array_v< T >, int > = 0, typename... Args>
T *	New (Args &&... args)

template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_bounded_array_v< T >, int > = 0>
ElementType *	New ()

template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
ElementType *	New (size_t count)

template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
ElementType *	New (size_t count, size_t alignment)
	Constructs an `alignment`-byte aligned array of `count` objects.

template<typename T , int &... kExplicitGuard, std::enable_if_t<!std::is_array_v< T >, int > = 0, typename... Args>
UniquePtr< T >	MakeUnique (Args &&... args)

template<typename T , std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
UniquePtr< T >	MakeUnique (size_t size)

template<typename T , std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
UniquePtr< T >	MakeUnique (size_t size, size_t alignment)

template<typename T , std::enable_if_t< is_bounded_array_v< T >, int > = 0>
UniquePtr< T >	MakeUnique ()

template<typename T , int &... kExplicitGuard, std::enable_if_t<!std::is_array_v< T >, int > = 0, typename... Args>
SharedPtr< T >	MakeShared (Args &&... args)

template<typename T , std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
SharedPtr< T >	MakeShared (size_t size)

template<typename T , std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
SharedPtr< T >	MakeShared (size_t size, size_t alignment)

template<typename T , std::enable_if_t< is_bounded_array_v< T >, int > = 0>
SharedPtr< T >	MakeShared ()

bool	Resize (void *ptr, size_t new_size)

void *	Reallocate (void *ptr, Layout new_layout)

size_t	GetAllocated () const

std::optional< Fragmentation >	MeasureFragmentation () const
	Returns fragmentation information for the allocator's memory region.

Public Member Functions inherited from pw::Deallocator
constexpr const Capabilities &	capabilities () const

constexpr bool	HasCapability (Capability capability) const
	Returns whether a given capability is enabled for this object.

void	Deallocate (void *ptr)

template<typename ElementType >
void	DeleteArray (ElementType *ptr, size_t count)

StatusWithSize	GetCapacity () const

bool	IsEqual (const Deallocator &other) const

template<typename T , int &... kExplicitGuard, std::enable_if_t<!std::is_array_v< T >, int > = 0>
void	Delete (T *ptr)

template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_bounded_array_v< T >, int > = 0>
void	Delete (ElementType *ptr)

template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
void	Delete (ElementType *ptr, size_t count)

Protected Types
using	ControlBlock = allocator::internal::ControlBlock

Protected Types inherited from pw::Deallocator
enum class	InfoType { kRequestedLayoutOf , kUsableLayoutOf , kAllocatedLayoutOf , kCapacity , kRecognizes }

Protected Member Functions
	PW_PACKED (struct) Region

	ChunkAllocator (Allocator &metadata_allocator, size_t alignment)

constexpr size_t	num_allocations () const

void	SetRegion (ByteSpan region)

void *	DoAllocate (allocator::Layout layout) override

void	DoDeallocate (void *ptr) override

Result< Layout >	DoGetInfo (InfoType info_type, const void *ptr) const override

virtual Region *	AllocateRegion (size_t min_size, size_t desired_size)=0

virtual size_t	TryDeallocateRegion (void *ptr)=0

Protected Member Functions inherited from pw::Allocator
constexpr	Allocator ()=default
	TODO(b/326509341): Remove when downstream consumers migrate.

constexpr	Allocator (const Capabilities &capabilities)

virtual void *	DoAllocate (Layout layout)=0

virtual bool	DoResize (void *ptr, size_t new_size)

virtual void *	DoReallocate (void *ptr, Layout new_layout)

virtual size_t	DoGetAllocated () const

virtual std::optional< Fragmentation >	DoMeasureFragmentation () const
	Returns fragmentation information for the allocator's memory region.

Protected Member Functions inherited from pw::Deallocator
constexpr	Deallocator ()=default
	TODO(b/326509341): Remove when downstream consumers migrate.

constexpr	Deallocator (const Capabilities &capabilities)

Result< Layout >	GetInfo (InfoType info_type, const void *ptr) const

Result< Layout >	GetRequestedLayout (const void *ptr) const

Result< Layout >	GetUsableLayout (const void *ptr) const

Result< Layout >	GetAllocatedLayout (const void *ptr) const

bool	Recognizes (const void *ptr) const

virtual void	DoDeallocate (void *ptr)=0

virtual Result< Layout >	DoGetInfo (InfoType, const void *) const

Additional Inherited Members
Public Types inherited from pw::Allocator
using	Fragmentation = allocator::Fragmentation

Public Types inherited from pw::Deallocator
using	Capabilities = allocator::Capabilities

using	Capability = allocator::Capability

using	Layout = allocator::Layout

Static Protected Member Functions inherited from pw::Deallocator
static Result< Layout >	GetInfo (const Deallocator &deallocator, InfoType info_type, const void *ptr)

static Result< Layout >	GetRequestedLayout (const Deallocator &deallocator, const void *ptr)

static Result< Layout >	GetUsableLayout (const Deallocator &deallocator, const void *ptr)

static Result< Layout >	GetAllocatedLayout (const Deallocator &deallocator, const void *ptr)

static bool	Recognizes (const Deallocator &deallocator, const void *ptr)

Static Protected Attributes inherited from pw::Deallocator
template<typename T >
static constexpr bool	is_bounded_array_v = ::pw::is_bounded_array_v<T>

template<typename T >
static constexpr bool	is_unbounded_array_v = ::pw::is_unbounded_array_v<T>

Member Function Documentation

◆ AllocateChunk() [1/2]

std::optional< OwnedChunk > pw::multibuf::v1_adapter::internal::ChunkAllocator::AllocateChunk	(	size_t	min_size,
		size_t	desired_size
	)

Allocates a chunk of at least min_size and up to desired_size bytes and returns it, or return std::nullopt if allocation fails.

◆ AllocateChunk() [2/2]

std::optional< OwnedChunk > pw::multibuf::v1_adapter::internal::ChunkAllocator::AllocateChunk ( size_t size )

inline

Allocates a chunk of size bytes and returns it, or return std::nullopt if allocation fails.

◆ AllocateRegion()

virtual Region * pw::multibuf::v1_adapter::internal::ChunkAllocator::AllocateRegion	(	size_t	min_size,
		size_t	desired_size
	)

protectedpure virtual

Returns a pointer to a region describing allocated memory of at least min_size and up to desired_size, or null if allocation failed.

Implemented in pw::multibuf::v1_adapter::internal::SingleChunkAllocator.

◆ DoAllocate()

void * pw::multibuf::v1_adapter::internal::ChunkAllocator::DoAllocate ( allocator::Layout layout )

overrideprotectedvirtual

Allocates a block of memory with the specified size and alignment.

Returns nullptr if the allocation cannot be made, or the layout has a size of 0.

Parameters

[in] layout Describes the memory to be allocated.

Implements pw::Allocator.

Reimplemented in pw::multibuf::v1_adapter::internal::SingleChunkAllocator.

◆ DoDeallocate()

void pw::multibuf::v1_adapter::internal::ChunkAllocator::DoDeallocate ( void * ptr )

overrideprotectedvirtual

Releases a previously-allocated block of memory.

The given pointer must have been previously provided by this memory resource; otherwise the behavior is undefined.

Parameters

[in] ptr Pointer to previously-allocated memory.

Implements pw::Deallocator.

Reimplemented in pw::multibuf::v1_adapter::internal::SingleChunkAllocator.

◆ DoGetInfo()

Result< Layout > pw::multibuf::v1_adapter::internal::ChunkAllocator::DoGetInfo	(	InfoType	info_type,
		const void *	ptr
	)		const

overrideprotectedvirtual

Returns deallocator-specific information about allocations.

Deallocators may support any number of InfoTypes. See that type for what each supported type returns. For unsupported types, this method returns UNIMPLEMENTED.

Reimplemented from pw::Deallocator.

◆ SetRegion()

void pw::multibuf::v1_adapter::internal::ChunkAllocator::SetRegion ( ByteSpan region )

protected

Sets the region used to provide chunks.

At most one region may be set by this method or a constructor.

◆ TryDeallocateRegion()

virtual size_t pw::multibuf::v1_adapter::internal::ChunkAllocator::TryDeallocateRegion ( void * ptr )

protectedpure virtual

Returns the number of bytes deallocated if the given pointer refers to memory described by a region previously returned by AllocateRegion, or 0 if it does not.

Implemented in pw::multibuf::v1_adapter::internal::SingleChunkAllocator.

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

pw_multibuf/v1_adapter/public/pw_multibuf/v1_adapter/internal/chunk_allocator.h

Overview

Public Member Functions

Protected Types

Protected Member Functions

Additional Inherited Members

Member Function Documentation

◆ AllocateChunk() [1/2]

◆ AllocateChunk() [2/2]

◆ AllocateRegion()

◆ DoAllocate()

◆ DoDeallocate()

◆ DoGetInfo()

◆ SetRegion()

◆ TryDeallocateRegion()