/*

* Copyright (c) 2004-2007 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:  An interface for objects that can be written into stream.

*

*/

#ifndef MVPBKSTREAMABLE_H

#define MVPBKSTREAMABLE_H

// INCLUDES

#include <e32std.h>

// FORWARD DECLARATIONS

class RReadStream;

class RWriteStream;

// CLASS DECLARATIONS

/**

 * An interface for objects that can be written into stream.

 */

class MVPbkStreamable

    {

    protected: // destructor

        /**

         * Destructor.

         */

        virtual ~MVPbkStreamable() { }

    public: // interface

        /**

         * Outputs this objects state to aStream.

         *

         * @param aStream A stream for writing the object state.

         */

        virtual void ExternalizeL( RWriteStream& aStream ) const = 0;

        /**

         * Returns the externalized size of the object in bytes.

         *

         * @return The externalized size of the object.

         */

        virtual TInt ExternalizedSize() const = 0;

        /**

         * Returns an extension point for this interface or NULL.

         *

         * @param aExtensionUid no extensions defined currently.

         * @return An extension point for this interface or NULL.

         */

        virtual TAny* StreamableExtension( TUid /*aExtensionUid*/ ) 

                { return NULL; }

    };

#endif // MVPBKSTREAMABLE_H

//End of file