#include <best_fit.h>

Inheritance diagram for pw::allocator::BestFitAllocator< BlockType >:

Public Types
using	Base = BlockAllocator< BlockType >

Public Types inherited from pw::allocator::BlockAllocator< BlockType_ >
using	BlockType = BlockType_

using	Range = typename BlockType::Range

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

using	Capability = allocator::Capability

using	Layout = allocator::Layout

Public Member Functions
constexpr	BestFitAllocator ()=default
	Constexpr constructor. Callers must explicitly call `Init`.

	BestFitAllocator (ByteSpan region)

Public Member Functions inherited from pw::allocator::BlockAllocator< BlockType_ >
Range	blocks () const
	Returns a `Range` of blocks tracking the memory of this allocator.

void	Init (ByteSpan region)

Fragmentation	MeasureFragmentation () const
	Returns fragmentation information for the block allocator's memory region.

Public Member Functions inherited from pw::allocator::internal::GenericBlockAllocator
	GenericBlockAllocator (const GenericBlockAllocator &)=delete

GenericBlockAllocator &	operator= (const GenericBlockAllocator &)=delete

	GenericBlockAllocator (GenericBlockAllocator &&)=delete

GenericBlockAllocator &	operator= (GenericBlockAllocator &&)=delete

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

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

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)

template<typename T >
T *	NewArray (size_t count)

template<typename T >
T *	NewArray (size_t count, size_t alignment)

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 , int &... kExplicitGuard, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
UniquePtr< T >	MakeUnique (size_t size)

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

template<typename T >
UniquePtr< T[]>	MakeUniqueArray (size_t size)

template<typename T >
UniquePtr< T[]>	MakeUniqueArray (size_t size, size_t alignment)

template<typename T , int &... kExplicitGuard, std::enable_if_t< is_bounded_array_v< T >, int > = 0, typename... Args>
void	MakeUnique (Args &&...)=delete

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 , int &... kExplicitGuard, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
SharedPtr< T >	MakeShared (size_t size)

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

template<typename T , int &... kExplicitGuard, std::enable_if_t< is_bounded_array_v< T >, int > = 0, typename... Args>
std::enable_if_t< is_bounded_array_v< T > >	MakeShared (Args &&...)=delete

bool	Resize (void *ptr, size_t new_size)

bool	Resize (void *ptr, Layout layout, size_t new_size)

void *	Reallocate (void *ptr, Layout new_layout)

void *	Reallocate (void *ptr, Layout old_layout, size_t new_size)

size_t	GetAllocated () const

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

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

void	Deallocate (void *ptr)

void	Deallocate (void *ptr, Layout layout)

template<typename T >
void	Delete (T *ptr)

StatusWithSize	GetCapacity () const

bool	IsEqual (const Deallocator &other) const

template<typename T , int &... kExplicitGuard, std::enable_if_t< is_bounded_array_v< T >, int > = 0, typename... Args>
void	WrapUnique (Args &&...)=delete

Private Member Functions
BlockResult< BlockType >	ChooseBlock (Layout layout) override

void	ReserveBlock (BlockType &block) override

void	RecycleBlock (BlockType &block) override

Additional Inherited Members
Static Public Attributes inherited from pw::allocator::BlockAllocator< BlockType_ >
static constexpr Capabilities	kCapabilities

static constexpr size_t	kPoisonInterval = PW_ALLOCATOR_BLOCK_POISON_INTERVAL

Protected Member Functions inherited from pw::allocator::BlockAllocator< BlockType_ >
void	Init (BlockType *begin)

template<typename Ptr >
internal::copy_const_ptr_t< Ptr, BlockType * >	FromUsableSpace (Ptr ptr) const

virtual void	DeallocateBlock (BlockType *&&block)

Protected Member Functions inherited from pw::allocator::internal::GenericBlockAllocator
constexpr	GenericBlockAllocator (Capabilities capabilities)

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

constexpr	Allocator (const Capabilities &capabilities)

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

constexpr	Deallocator (const Capabilities &capabilities)

template<typename T , std::enable_if_t<!std::is_array_v< T >, int > = 0>
UniquePtr< T >	WrapUnique (T *ptr)

template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
UniquePtr< T >	WrapUnique (ElementType *ptr, size_t size)

template<typename T >
UniquePtr< T[]>	WrapUniqueArray (T *ptr, size_t size)

Static Protected Member Functions inherited from pw::allocator::internal::GenericBlockAllocator
template<typename BlockType >
static constexpr Capabilities	GetCapabilities ()

static void	CrashOnAllocated (const void *allocated)

static void	CrashOnOutOfRange (const void *freed)

static void	CrashOnDoubleFree (const void *freed)
	Crashes with an informational message that a given block was freed twice.

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

template<typename T >
static constexpr bool	is_unbounded_array_v

Detailed Description

template<typename BlockType = BestFitBlock<uintptr_t>>
class pw::allocator::BestFitAllocator< BlockType >

Block allocator that uses a "best-fit" allocation strategy.

In this strategy, the allocator handles an allocation request by looking at all unused blocks and finding the smallest one which can satisfy the request.

This algorithm may make better use of available memory by wasting less on unused fragments, but may also lead to worse fragmentation as those fragments are more likely to be too small to be useful to other requests.

Constructor & Destructor Documentation

◆ BestFitAllocator()

template<typename BlockType = BestFitBlock<uintptr_t>>

pw::allocator::BestFitAllocator< BlockType >::BestFitAllocator ( ByteSpan region )

inline

Non-constexpr constructor that automatically calls Init.

Parameters

[in] region Region of memory to use when satisfying allocation requests. The region MUST be valid as an argument to BlockType::Init.

Member Function Documentation

◆ ChooseBlock()

template<typename BlockType = BestFitBlock<uintptr_t>>

BlockResult< BlockType > pw::allocator::BestFitAllocator< BlockType >::ChooseBlock ( Layout layout )

inlineoverrideprivatevirtual

Selects a free block to allocate from.

This method represents the allocator-specific strategy of choosing which block should be used to satisfy allocation requests. If the returned result indicates success, block will be replaced by the chosen block.

Parameters

block	Used to return the chosen block.
layout	Same as `Allocator::Allocate`.

Implements pw::allocator::BlockAllocator< BlockType_ >.

◆ RecycleBlock()

template<typename BlockType = BestFitBlock<uintptr_t>>

void pw::allocator::BestFitAllocator< BlockType >::RecycleBlock ( BlockType & block )

inlineoverrideprivatevirtual

Indicates that a block is now free.

Does nothing by default. Derived class may overload to do additional bookkeeeping.

Parameters

block The block being freed.

Reimplemented from pw::allocator::BlockAllocator< BlockType_ >.

◆ ReserveBlock()

template<typename BlockType = BestFitBlock<uintptr_t>>

void pw::allocator::BestFitAllocator< BlockType >::ReserveBlock ( BlockType & block )

inlineoverrideprivatevirtual

Indicates that a block will no longer be free.

Does nothing by default. Derived class may overload to do additional bookkeeeping.

Parameters

block The block being freed.

Reimplemented from pw::allocator::BlockAllocator< BlockType_ >.

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

pw_allocator/public/pw_allocator/best_fit.h

Public Types

Public Member Functions

Private Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ BestFitAllocator()

Member Function Documentation

◆ ChooseBlock()

◆ RecycleBlock()

◆ ReserveBlock()