CMemAllocator Class (Compact 2013)

3/26/2014

CBaseAllocator Class

     CMemAllocator Class

This class provides support for IMemAllocator by using the new operator to allocate memory.

Derived from CBaseAllocator, it overrides the CBaseAllocator::Alloc member function to allocate a single block of memory large enough to hold all requested data areas, and then allocates (using the new operator) a CMediaSample object for each requested buffer pointing into the data area.

The CBaseInputPin and CBaseOutputPin classes instantiate CMemAllocator objects as the default allocator if no other suitable allocator is provided.

All member functions in this class that return HRESULT and accept a pointer as a parameter return E_POINTER when passed a null pointer.

Member Functions

Member function	Description
Alloc	Allocates memory for a media sample (overrides CBaseAllocator::Alloc).
CMemAllocator	Constructs a CMemAllocator object.
ReallyFree	Frees memory when called from the destructor (or from Alloc when reallocating for new size or count).

Overrideable Member Functions

Member function	Description
Free	Indicates an overridden CBaseAllocator::Free member function, called when a decommit operation is complete to free memory.

Implemented IMemAllocator Methods

Method	Description
CreateInstance	Creates new instances of CMemAllocator in the factory template.
SetProperties	Sets the number of media samples and the size of each.

Requirements

Header	dshow.h, Streams.h
Library	ole32.lib, Ole32auth.lib, Strmbase.lib, Strmiids.lib, uuid.lib

See Also

Reference

DirectShow Classes