FSpanAllocator Class Reference

#include <SpanAllocator.h>

Public Member Functions
ENGINE_API	FSpanAllocator (bool bInGrowOnly=false)
int32	Allocate (int32 Num=1)
void	Free (int32 BaseOffset, int32 Num=1)
ENGINE_API void	Reset ()
ENGINE_API void	Empty ()
int32	GetSparselyAllocatedSize () const
int32	GetMaxSize () const
int32	GetNumFreeSpans () const
int32	GetNumPendingFreeSpans () const
SIZE_T	GetAllocatedSize () const
ENGINE_API void	Consolidate ()

Detailed Description

Allocator for spans from some range that is allowed to grow and shrink to accomodate the allocations. Implementation is biased towards the case where allocations and frees are performed in bulk, if they are interleaved performance will degrade. Prefers allocations at the start of the range, such that the high-watermark can be reduced optimally. Primarily optimized for the use-case where span size == 1, for variable span size allocation performance is sub-optimal as it does not accelerate the search for larger allocs.

Constructor & Destructor Documentation

FSpanAllocator()

FSpanAllocator::FSpanAllocator

(

bool

bInGrowOnly = false

)

If bInGrowOnly is true the size reported by GetMaxSize() will never decrease except when for when Reset() or Empty() is called.

Member Function Documentation

Allocate()

int32 FSpanAllocator::Allocate ( int32  Num = 1 )

inline

Consolidate()

void FSpanAllocator::Consolidate

(

)

Between these calls to Free just appends the allocation to the free list, rather than trying to merge with existing allocations. At EndDeferMerges the free list is consolidated by sorting and merging all spans. This amortises the cost of the merge over many calls.

Empty()

void FSpanAllocator::Empty

(

)

Free()

void FSpanAllocator::Free ( int32  BaseOffset, int32  Num = 1  )

inline

GetAllocatedSize()

SIZE_T FSpanAllocator::GetAllocatedSize ( ) const

inline

GetMaxSize()

int32 FSpanAllocator::GetMaxSize ( ) const

inline

GetNumFreeSpans()

int32 FSpanAllocator::GetNumFreeSpans ( ) const

inline

GetNumPendingFreeSpans()

int32 FSpanAllocator::GetNumPendingFreeSpans ( ) const

inline

GetSparselyAllocatedSize()

int32 FSpanAllocator::GetSparselyAllocatedSize ( ) const

inline

Reset()

void FSpanAllocator::Reset

(

)

---

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

• Engine/Source/Runtime/Engine/Public/SpanAllocator.h
• Engine/Source/Runtime/Engine/Private/SpanAllocator.cpp