/*

* Copyright (c) 2009 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 "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: 

*

*/

#ifndef CUSBPNPACKET_H

#define CUSBPNPACKET_H

//  INCLUDES

#include <e32base.h>    // For CBase

// CONSTANTS

// MACROS

// DATA TYPES

// FUNCTION PROTOTYPES

// FORWARD DECLARATIONS

/**

*  CUsbPnPacket

*  Implements circular data packet buffer functionality.

*/

class CUsbPnPacket : public CBase

    {

    public:

        /**

        * Two-phased constructor.

        */

        static CUsbPnPacket* NewL( CUsbPnPacket* aPacket, TInt aNum );

        /**

        * Destructor

        */

        ~CUsbPnPacket();

        /**

        * Returns the next packet.

        * @return CUsbPnPacket* The next packet.

        */

        CUsbPnPacket& NextPacket() const;

        /**

        * Returns the buffer.

        * @return TDes8* Buffer

        */

        HBufC8& Buffer() const;

        /**

        * Returns true if packet contains data already.

        * @return TBool Sync flag.

        */

        TBool PacketInUse() const;

        /**

        *

        */

        TInt PacketNumber() const;

        /**

        *Release packet's buffer after usage.

        *Realloc to standard size if bigger than usual.

        */

        void ReleaseL();

        /**

        *Realloc packet's buffer if bigger needed.

        */

        void ReallocBufferL( const TInt aNeededLength );

    private:

        /**

        * Constructor. Allocates memory.

        * @param CUsbPnPacket* aUsbPacket   A packet which is linked as next packet to this packet.

        * @param TInt aNum                  Serial number of the created packet for easing debugging.

        */

        CUsbPnPacket( CUsbPnPacket* aPacket, TInt aNum );

        /**

        * By default Symbian 2nd phase constructor is private.

        */

        void ConstructL();

        /* defined for preventing misuse */

        explicit CUsbPnPacket(const CUsbPnPacket&);

        CUsbPnPacket& operator=(const CUsbPnPacket&);

        // Pointer to next packet in circular buffer.

        CUsbPnPacket*    iNextPacket;

        // Ownership. Pointer to buffer

        HBufC8*          iBuffer;

        // Order number

        TInt            iNumber;

    };

#endif  // #ifndef CUSBPNPACKET_H