/*

 * 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