/*

* Copyright (c) 2004-2006 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:    Provides a comfort noise generator class

*

*/

#ifndef MCCCNGENERATOR_H

#define MCCCNGENERATOR_H

#include <e32base.h>

#include <mmf/common/mmfutilities.h>

// FORWARD DECLARATIONS

class CMMFDevSound;

class CErrorConcealmentIntfc;

/**

* MCC Comfort noise generator

*

* @lib MMccJitterBuffer.lib

* @since Series 60 3.0

*/

NONSHARABLE_CLASS( CMccCnGenerator ) : public CBase

    {

    public:  // Constructors and destructor 

        /**

        * Two phased constructor

        */

        static CMccCnGenerator* NewL( const TFourCC& aAudioType, 

                CMMFDevSound& aDevSound );

        /**

        * Destructor

        */

        virtual ~CMccCnGenerator();

    public: // New functions

        /**

        * Generates an SID packet to given buffer

        * @since Series 60 3.0

        * @param aPayload Buffer to be filled with SID data

        * @param aRequestSize Amount of data to be generated to buffer.

        * @return void

        */

        void GenerateSidPacket( TDes8& aPayload, TInt aRequestSize );

        /**

        * Jitterbuffer has noted that frames were missing, so error concealment

        * needs to be done to some frames. This function calls the error 

        * concealment interface's error concealment function.

        * @since Series 60 3.0

        * @param None

        * @return void

        */

        void ConcealErrorForNextFrame() const;

        /**

        * Returns the current DTX status

        * @since Series 60 3.0

        * @param None

        * @return TBool ETrue if DTX period ongoing

        */

        inline TBool DtxPeriodStatus() const

            {

            return ( iDtxPeriodStarted );

            }

        /**

        * Decide whether we are in DTX period or in normal speech period

        * @since Series 60 3.0

        * @param aData Buffer containing the data

        * @return void

        */

        void DoDtxDecision( const TDesC8& aData );

        /**

        * Check if the given databuffer is a SID frame for current codec

        * @since Series 60 3.0

        * @param aData Buffer containing the data

        * @return TBool ETrue if the aBuffer is a SID for current codec

        */

        TBool IsSidBuffer( const TDesC8& aData ) const;

    private: // New functions

        /**

        * Generates an AMR CN packet into aPayload

        * @since Series 60 3.0

        * @param aPayload

        * @return void

        */

        void GenerateAmrNoDataPacket( TDes8& aPayload ) const;

        /**

        * Generates an VoIP NO_DATA frame into aPayload

        * @since Series 60 3.0

        * @param aPayload Buffer to be filled with VoIP NO_DATA information

        * @param aRequestSize Amount of data to be generated to buffer.

        * @return void

        */

        void GenerateVoIPNoDataPacket( TDes8& aPayload, TInt aRequestSize ) const;

    private: //Constructors

        /**

        * C++ default constructor.

        */

        CMccCnGenerator( const TFourCC& aAudioType, CMMFDevSound& aDevSound );

        /**

        * By default Symbian 2nd phase constructor is private.

        */

        void ConstructL();

    private:    // Data

        // Audio type

        TFourCC iAudioType;

        // Sound device for Error Concealment IF creation

        CMMFDevSound& iDevSound;

        // Error concealment interface

        CErrorConcealmentIntfc* iErrorConcealer;

        // Generated CN frames

        TInt iGeneratedCnFrames;

        // DTX period started

        TBool iDtxPeriodStarted;

    private:    // Friend classes

    // Friend class for EUNIT tests

    #ifdef TEST_EUNIT

        friend class UT_CMccCnGenerator;

    #endif

    };

#endif  // MCCCNGENERATOR_H