// Copyright (c) 2006-2009 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:

 //

 /**

  @file

  @publishedPartner

  @released

 */

 #ifndef MAUDIOPROCESSINGUNIT_H

 #define MAUDIOPROCESSINGUNIT_H

 #include <e32base.h>

 #include <f32file.h>

 #include <mmf/common/mmfcontroller.h>

 #include <a3f/a3fbase.h>

 class MAudioProcessingUnitObserver;

 /**

  * A generic interface for audio processing units.

  */

 class MAudioProcessingUnit

 	{

 public:

 	/**

 	 * Fetches the identifier of the context in which this processing unit exists.

 	 *

 	 * @return TUid context instance id.

 	 */

 	virtual TAudioContextId ContextId() const = 0;

 	/**

 	 * Fetches the specified interface to this processing unit.

 	 * The interface must not be deleted by the client.

 	 * The processing unit must be removed once from the context using

 	 * any of the retrieved processing unit interfaces.

 	 * @param aTypeId the type of the interface

 	 */

 	virtual TAny* Interface(TUid aType)=0;

 	/**

 	 * Registers a processing unit observer.

 	 *

 	 * The observer must be unregistered before the processing unit is removed from the context.

 	 * 

 	 * @see MAudioProcessingUnitObserver for further inforamtion about the observer usage.

 	 * @param aObserver a reference to the observer to register

 	 * @return an error code. KErrNone if successful.

 	 *         KErrNotSupported the processing unit does not provide support for this type of observation.

 	 *         Other system wide error codes are also possible.

 	 */

 	virtual TInt RegisterProcessingUnitObserver(MAudioProcessingUnitObserver& aObserver)=0;

 	/**

 	 * Unregisters audio processing unit observer.

 	 *

 	 * @see RegisterProcessingUnitObserver for further information.

 	 * @param aObserver a reference to the processing unit observer to unregister.

 	 * @return an error code. KErrNone if successful.

 	 */

 	virtual void UnregisterProcessingUnitObserver(MAudioProcessingUnitObserver& aObserver)=0; 

 	/**

 	 * Returns the component instance id.

 	 *

 	 * @return TUid component instance id.

 	 */

 	virtual TAudioComponentId InstanceId() const = 0;

 	/** 

 	 * Returns if the component is the same type of the given feature Uid. 

  	 * @param aTypeId a feature Uid to compare with.

 	 */

 	virtual TBool IsTypeOf(TUid aTypeId) const =  0;

 	};

 #endif // MAUDIOPROCESSINGUNIT_H