// Copyright (c) 2002-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// include\mmf\server\mmfdatabuffer.h

// 

//

#ifndef __MMF_SERVER_DATABUFFER_H__

#define __MMF_SERVER_DATABUFFER_H__

#include <e32base.h>

#include <mmf/server/mmfbuffer.h>

/** 

@publishedAll

@released

Default buffer size if none is specified.

*/

static const TInt KMMFDataBufferDefaultBufferSize = 32;

/**

@publishedAll

@released

This class is an abstract class for databuffers that can be presented in the form of a descriptor.

A constructor is provided which instantiates a CMMFDescriptorBuffer buffer by default.

@see CMMFDescriptorBuffer

*/

class CMMFDataBuffer : public CMMFBuffer

	{

public:

	IMPORT_C static CMMFDataBuffer* NewL();

	IMPORT_C static CMMFDataBuffer* NewL(TInt aMaxBufferSize);

	/**

	Destructor.

	*/

	virtual ~CMMFDataBuffer() {};

	/**

	Returns a reference to the data contained in the buffer (non const version).

	This is a virtual function that each derived class must implement.

	@return A reference to the buffer.

	*/

	virtual TDes8& Data() = 0;

	/**

	Returns a reference to the data contained in the buffer (const version).

	This is a virtual function that each derived class must implement.

	@return A reference to the buffer.

	*/

	virtual const TDesC8& Data() const = 0;

	/**

	Returns the buffer size, in bytes.

	This is a virtual function that each derived class must implement.

	@return The buffer size in bytes.

	*/

	virtual TUint BufferSize() const = 0;

	/**

	Sets the request size. 

	Used where a component, such as a data source,

	may not be able to write to the entire maximum length of the buffer

	(variable bit rate codecs for example).

	This is a virtual function that each derived class must implement.

	@param  aSize

	        The requested size, in bytes.

	*/

	virtual void SetRequestSizeL(TInt aSize) = 0;

protected:

	/**

	Protected constructor.

	*/

	CMMFDataBuffer(TUid aType): CMMFBuffer(aType) {};

	};

/**

@publishedAll

@released

This class is a wrapper class to give a descriptor the same API as a CMMFDataBuffer.

The purpose of this class is that components such as codecs can use CMMFDataBuffers transparently

without having to be concerned with whether the buffer is a descriptor buffer

or a transfer buffer.

*/

class CMMFDescriptorBuffer : public CMMFDataBuffer

	{

public:

	IMPORT_C static CMMFDescriptorBuffer* NewL();

	IMPORT_C static CMMFDescriptorBuffer* NewL(TInt aMaxBufferSize);

	IMPORT_C ~CMMFDescriptorBuffer();

	IMPORT_C void ReAllocBufferL(TInt aMaxBufferSize);

	virtual TDes8& Data();

	virtual const TDesC8& Data() const;

	virtual void SetStatus(TBufferStatus aStatus);

	virtual void SetRequestSizeL(TInt aSize);

	virtual TUint BufferSize() const;

	virtual void SetPosition (TUint aPosition);

private:

	CMMFDescriptorBuffer() : CMMFDataBuffer(KUidMmfDescriptorBuffer), iPtr(0,0,0) {};

	void ConstructL(TInt aMaxBufferSize);

private:

	TUint8* iData;

	TPtr8 iPtr;

	};

/**

@publishedAll

@released

This class is a wrapper class to give a transfer buffer/window the same API as a CMMFDataBuffer.

The purpose of this class is so that components such as codecs can use CMMFDataBuffers transparently

without having to be concerned with whether the buffer is a descriptor buffer

or a transfer buffer.

The class assumes that a valid RTransferWindow with a RTransferBuffer mapped in already exists.

Note:

CMMFTransferBuffers are not supported in EKA2.

*/

class RTransferWindow

	{

	// dummy class

	};

class CMMFTransferBuffer : public CMMFDataBuffer

	{

public:

	IMPORT_C static CMMFTransferBuffer* NewL(RTransferWindow& aTransferWindow, TUint aDataLength = 0);

	IMPORT_C ~CMMFTransferBuffer();

	virtual TDes8& Data();

	virtual const TDesC8& Data() const;

	virtual TUint BufferSize() const;

	virtual void SetRequestSizeL(TInt aSize);

	virtual void SetPosition (TUint aPosition);

	IMPORT_C RTransferWindow& TransferWindow();

	IMPORT_C void MapOutBuffer();

	IMPORT_C TInt UpdateTransferWindow(RTransferWindow& aTransferWindow, TUint aDataLength = 0);

private:

	/**

	Private constructor.

	*/

	CMMFTransferBuffer() : CMMFDataBuffer(KUidMmfTransferBuffer), iPtr(0,0,0){};

	void ConstructL(RTransferWindow& aTransferWindow, TUint aDataLength);

private:

	RTransferWindow iTransferWindow;

	TBool iTransferWindowMappedInOK;

	TPtr8 iPtr;

	};

/**

@publishedAll

@released

This class is a wrapper class intended to provide support for shared I/O buffers under EKA2

This class, unlike other data buffers does not own memory - rather it contains a pointer to already allocated memory

The purpose of this class is that components such as codecs can use CMMFDataBuffers transparently

without having to be concerned with whether the buffer is a standard buffer or memory residing in shared I/O

Users of this class need to be very careful when using buffers of this type.

It cannot be assumed that a buffer of this type can be written/read by any process other than the current one - example - handing CMMFPtrBuffer to the file server may not work since the file server's process may not have access to write data buffer.

*/

class CMMFPtrBuffer : public CMMFDataBuffer

	{

public:

	IMPORT_C static CMMFPtrBuffer* NewL();		//unitialised, pointer will be set via SetPtr

	IMPORT_C static CMMFPtrBuffer* NewL(const TPtr8& aPtr);

	IMPORT_C ~CMMFPtrBuffer();

	IMPORT_C void SetPtr(const TPtr8& aPtr);

	virtual TDes8& Data();

	virtual const TDesC8& Data() const;

	virtual void SetStatus(TBufferStatus aStatus);	

	virtual void SetRequestSizeL(TInt aSize);

	virtual TUint BufferSize() const;

	virtual void SetPosition (TUint aPosition);

private:

	CMMFPtrBuffer() : CMMFDataBuffer(KUidMmfPtrBuffer), iPtr(0,0,0) {};

	void ConstructL(const TPtr8& aPtr);

private:

	TPtr8 iPtr;

	};

#endif