/*

* Copyright (c) 2004 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members

* which accompanies this distribution, and is available

* at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:  This is the definition of the audio effects base class.

*

*

*/

#ifndef CAUDIOEFFECT_H

#define CAUDIOEFFECT_H

// INCLUDES

#include <e32base.h>

// FORWARD DECLARATION

class MAudioEffectObserver;

// CLASS DECLARATION

/**

*  This is the base class for audio effects.

*

*  @lib AudioEffectBase.lib

*  @since 3.0

*/

class CAudioEffect : public CBase

	{

	public: // Constructors and destructor

		/**

        *	Destructor

        */

		IMPORT_C virtual ~CAudioEffect();

    public: // New functions

		/**

        * Apply effect settings

        * @since 3.0

        */

		virtual void ApplyL() = 0;

		/**

        * Disable the effect

        * @since 3.0

        */

		IMPORT_C virtual void DisableL();

		/**

        * Enable the effect

        * @since 3.0

        */

		IMPORT_C virtual void EnableL();

		/**

        * Enforce the effect.

        * @since 3.0

        * @param aEnforced Indicate the effect is to be enforced or not. ETrue = Enforced.

        */

		IMPORT_C virtual void EnforceL( TBool aEnforced );

		/**

        * Check if this effect object currently has update rights.

        * A client can lose update rights in some hardware platforms where there are a limited

        * number of instances of an effect that can exist at the same time. When an effect instance

        * has lost update rights the user can still change settings, but any calls to Apply the

        * settings will be deferred until update rights are regained.

        * @since 3.0

        * @return ETrue if this object currently has rights to update the settings of this effect,

        *         EFalse otherwise.

        */

		IMPORT_C virtual TBool HaveUpdateRights() const;

		/**

        * Check if the effect is enabled

        * @since 3.0

        * @return ETrue if the effect is enabled, EFalse if the effect is disabled.

        */

		IMPORT_C virtual TBool IsEnabled() const;

		/**

        * Check if the effect is enforced.

        * @since 3.0

        * @return ETrue if the effect is enforced, EFalse if the effect isn ot enforced.

        */

		IMPORT_C virtual TBool IsEnforced() const;

		/**

        * Adds the specified observer to the list of observers to be notified when

        * the effect object changes state.

        * @since 3.0

        * @param aObserver Object to be added to notifier list.

        */

		IMPORT_C void RegisterObserverL( MAudioEffectObserver& aObserver );

		/*

        * Get the unique identifier of the audio effect

        * @since 3.0

        * @return Unique identifier of the audio effect object.

        */

		virtual TUid Uid() const = 0 ;

		/**

        * Removes the specified observer from the list of observers.

        * @since 3.0

        * @param aObserver object to be removed.

        */

		IMPORT_C void UnRegisterObserver( MAudioEffectObserver& aObserver );

	protected:

		/**

		* Private C++ constructor for this class.

        * @since 3.0

        * @param aEffectObserver	reference to event observer object

        * @return -

        */

		IMPORT_C CAudioEffect();

		/**

		* Internal function to package data into a descriptor.

        * @since 3.0

        * @return A descriptor containing the effect data.

        */

		virtual const TDesC8& DoEffectData() = 0 ;

		/**

		* Internal function to unpack effect data

        * @since 3.0

        * @param aEffectDataBuffer Descriptor containing packed effect data

        */

        virtual void SetEffectData( const TDesC8& aEffectDataBuffer ) = 0;

	protected: // Data

		// Flag to indicate whether the effect is enabled or not

		TBool iEnabled;

		// Flag to indicate wheter the effect is enforced

		TBool iEnforced;

		// Flag to indicate wheter the effect current has update rights

		TBool iHaveUpdateRights;

		// Pointer to Observers

		RPointerArray<MAudioEffectObserver> iObservers;

	};

#endif	// of CAUDIOEFFECT_H

// End of File