/*

* 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:    Formatter classes for decoding of RTP payload format

*                for AMR ( narrow band ) audio codecs.

*

*/

#ifndef AMRPAYLOADDECODER_H

#define AMRPAYLOADDECODER_H

// INCLUDES

#include <e32std.h>

#include "amrpayloadformatter.h"

#include "streamformatter.h"

// FORWARD DECLARATIONS

class CAmrPayloadHeader;

class CAmrTocEntry;

class TStreamDecoder;

// CLASS DECLARATION

/**

* The AMR payload decoder for bandwidth efficient mode.

*

* @lib <TBD>

* @since Series-60 2.1

*/

class CAmrPayloadDecoder : public CAmrPayloadFormatter

    {

    public:  // Constructors and destructor

        /**

        * Two-phased constructor.

        */

        static CAmrPayloadDecoder* NewL( TBool aIsNb );

        /**

        * Destructor.

        */

        virtual ~CAmrPayloadDecoder( );

    public: // New functions

        /**

        * Decode payload data received in the payload buffer.

        * If AMR FEC is used and redundant frames are discarded, time stamp is

        * increased to correspond start of remaining frames.

        *

        * @since    Series 60 3.0

        * @param    aTimeStamp      Time stamp from RTP header

        * @param    aTimeStampInc   Unit for time stamp incrementing

        * @return TInt - Number of AMR frames decoded

        */

        virtual TInt DecodePayload( TUint32& aTimeStamp,

                                    TUint32 aTimeStampInc );

        /**

        * Get AMR codec mode request ( CMR ) received in the payload.

        * @since Series-60 2.1

        * @return TAmrModeRequest - AMR codec mode request ( CMR ) received

        */

        TAmrModeRequest ModeRequest() const;

        /**

        * Get AMR frames decoded from the payload.

        * Number of frames equals the value returned by `DecodePayload( )' function.

        * @since Series-60 2.1

        * @return TAmrFrame[] - Array of AMR frames decoded

        */

        TAmrFrame* Frames( );

    protected:

        /**

        * Constructor.

        */

        CAmrPayloadDecoder( TBool aIsNb );

    private:

        /**

        * By default Symbian 2nd phase constructor is private.

        */

        void ConstructL( );

    protected: // Functions

        /**

        * Decode the AMR payload ( for one RTP packet ) from a given buffer.

        * Decoded values are returned in `iFrames' array.

        * @since Series-60 2.1

        * @param aBuffer - [input] Buffer to decode data from.

        * @param aBufferSize - [input] Buffer size in bytes.

        * @return None

        */

        void Decode( const TUint8* aBuffer,

                     TInt aBufferSize );

        /**

        * Decode TOC ( Table of Contents ) entries from a given buffer at the given

        * position. Decoded information are stored in `iFrames' array.

        * Byte and bit positions are updated after decoding is done.

        * @since Series-60 2.1

        * @param aBuffer - [input] Buffer to decode data from.

        * @param aBufferSize - [input] Buffer size in bytes.

        * @param aByteIndex - [input] Starting byte index ( starts from zero ).

        *                     [output] Byte index updated after encoding.

        * @param aBitIndex - [input] Starting bit index ( starts from zero ).

        *                    [output] Bit index updated after encoding.

        * @return Number of TOC entries decoded.

        */

        TInt DecodeTableOfContents( const TUint8* aBuffer, 

                                    TInt aBufferSize, 

                                    TInt& aByteIndex, 

                                    TInt& aBitIndex );

        /**

        * Calculate frames' starting Byte and Bit positions in a given payload buffer

        * and update `iFrames' array with the frames' positions.

        * @since Series-60 2.1

        * @param aBuffer - [input] Payload buffer.

        * @param aBufferSize - [input] Buffer size in bytes.

        * @param aFrameCount - [input] Number of frames included in the payload buffer.

        * @return None

        */

        virtual void CalculateFramePosition( const TUint8* aBuffer, 

                                             TInt aFrameCount );

    protected:  // From CAmrPayloadFormatter

        /**

        * Initializes decoder. Decoder should be initialized when starting

        * playing.

        *

        * @since    Series 60 3.0

        * @param    None

        * @return   void

        */

        virtual void DoInitialize();

    private:    // Functions

        /**

        * Compares two AMR frames.

        *

        * @since    Series 60 3.0

        * @param    aBuffer         Payload buffer containing one AMR frame

        * @param    aFrameToCmp     AMR frame to which compare

        * @param    aBitsToCmp      Number of bits to search

        * @return   ETrue if contents are same; otherwise EFalse

        */

        TBool CompareBuffers( const TDesC8& aBuffer,

                              const TAmrFrame& aFrameToCmp, 

                              TInt aBitsToCmp ) const;

    protected: // Data

        // Payload decoding

        // Decoder for payload header

        CAmrPayloadHeader* iHeaderDecoder;

        // Decoder for TOC entry

        CAmrTocEntry* iTocEntryDecoder;

        // Frames decoded from received buffer

        TInt iDecodedFrames;

        // Time stamp to give for next frame being decoded

        TUint32 iTimeStamp;

        // Unit for time stamp incrementing/decrementing

        TUint32 iTimeStampInc;

        private:

        #ifdef TEST_EUNIT

            friend class UT_CAmrPayloadDecoder;

            friend class UT_CAmrPayloadFormatRead;

        #endif   

    };

#endif  // __AMRPAYLOADDECODER_H