IAAFCachePageAllocator Interface Reference

This interface is used by the toolkit for allocation and deallocation of pages in a page cache. More...

List of all members.

Public Member Functions
HRESULT	Initialize ([in] aafUInt32 pageCount,[in] aafUInt32 pageSize)
	Initialize.
HRESULT	Allocate ([out] aafMemPtr_t *pPage)
	Allocate a cache page.
HRESULT	Deallocate ([in] aafMemPtr_t page)
	Dellocate a cache page.

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Detailed Description

This interface is used by the toolkit for allocation and deallocation of pages in a page cache.

It is typically implemented by clients requiring control over how memory is allocated. By implementing this interface clients are able to control aspects of memory allocation such as the source from which the memory is obtained, how the memory is aligned etc.

Notes for implementers -

• Allocate() will be called a maximum of pageCount times, it may be called fewer times.

• Deallocate() will be called the same number of times as Allocate().

• Some uses of this interface never call Allocate() after Deallocate(), implementors of this interface should not assume that this is always the case.

• Allocate() should indicate failure by returning AAFRESULT_NOMEMORY (and not by returning a NULL pointer.)

• Deallocate() should accept a NULL pointer (and do nothing) as does operator delete.

• It is valid to allocate all the pages during Initialize() or during the first call to Allocate(). For example, if aligned pages are required, allocating all the pages contiguously mans paying the space cost of alignment once instead of per-page.

• Initialize() will be called only once.

In addition to the specific error results listed for each method, all methods in this interface may also return one of the following values:

AAFRESULT_NOMEMORY

• insufficient system memory is available to perform the operation.

Definition at line 2657 of file AAF.idl.

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Member Function Documentation

HRESULT IAAFCachePageAllocator::Allocate

(

[out] aafMemPtr_t *

pPage

)

Allocate a cache page.

Parameters:

pPage

[out] Pointer to the newly allocated page

HRESULT IAAFCachePageAllocator::Deallocate

(

[in] aafMemPtr_t

page

)

Dellocate a cache page.

Parameters:

page	[in] Pointer to the page to deallocate

HRESULT IAAFCachePageAllocator::Initialize	(	[in] aafUInt32	pageCount,
		[in] aafUInt32	pageSize
	)

Initialize.

Parameters:

pageCount	[in] Maximum number of pages to allocate
pageSize	[in] Size in bytes of each page