Class TMemBuf

class TMemBuf : public TStreamBuf;

Description

A stream buffer that uses plain memory for its implementation.

A stream of this type is used by RMemWriteStream and RMemReadStream objects. It also has intermediate buffering capabilities.

This is a seekable stream buffer.

Derivation

• MStreamBuf - A stream buffer that provides a generic I/O interface for streamed data

• TStreamBuf - Adds buffering capabilities to a stream buffer

• TMemBuf - A stream buffer that uses plain memory for its implementation

Members

Defined in TMemBuf:
DoSeekL(), OverflowL(), Set(), TMemBuf(), UnderflowL()

Inherited from MStreamBuf:
Close(), DoRelease(), DoSynchL(), ERead, EWrite, PushL(), Read(), ReadL(), Release(), SeekL(), SizeL(), Synch(), SynchL(), TMark, TRead, TWrite, TellL(), Write(), WriteL()

Inherited from TStreamBuf:
Avail(), DoReadL(), DoWriteL(), End(), Ptr(), SetBuf(), SetEnd(), SetPtr(), TArea

See also:

• RMemWriteStream
• RMemReadStream

IMPORT_C TMemBuf();

Description

Constructs an empty object.

Call Set() before using the object.

IMPORT_C void Set(TUint8 *aPtr, TUint8 *anEnd, TInt aMode=ERead|EWrite);

Description

Sets up the stream to use the specified area of plain memory.

Parameters

TUint8 *aPtr The start address for the area of plain memory that hosts the stream and that also acts as the intermediate buffer. TUint8 *anEnd The end address for the area of plain memory that hosts the stream and that also acts as the intermediate buffer. The addressed byte is outside the memory area. TInt aMode The mode in which the stream is to be used. It can be used in either or both read and write modes, represented by ERead and EWrite.

See also:

• MStreamBuf::TRead
• MStreamBuf::TWrite

protected: virtual IMPORT_C TInt UnderflowL(TInt aMaxLength);

Description

Re-fills the intermediate buffer and resets the start and end points of the read area.

The implementation of this function depends on the way the stream itself is implemented. For example, the in-memory streams have simple implementations.

Parameters

TInt aMaxLength The maximum amount of data required for the intermediate buffer.

Return value

TInt The amount of data available in the intermediate buffer.

protected: virtual IMPORT_C void OverflowL();

Description

Empties the intermediate buffer and resets the start and end points of the write area.

The implementation of this function depends on the way the stream itself is implemented. For example, the in-memory streams have simple implementations.

protected: virtual IMPORT_C TStreamPos DoSeekL(TMark aMark, TStreamLocation aLocation, TInt anOffset);

Description

Parameters

TMark aMark TStreamLocation aLocation TInt anOffset

Return value

TStreamPos