/*

* 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 "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:  IPProxy UDP protocol expression for a regular UDP message

*                connection.

*

*/

// INCLUDE FILES

#include "CExprUDPMsg.h"

#include "CommRouterDefinitions.h"

#include "MExpressionObserver.h"

#define DEBUG_FILENAME "IPProxyEngine.log"

#include "DebugPrint.h"

// ============================ MEMBER FUNCTIONS ===============================

// -----------------------------------------------------------------------------

// CExprUDPMsg::CExprUDPMsg

// -----------------------------------------------------------------------------

//

CExprUDPMsg::CExprUDPMsg( MExpressionObserver* aObserver )

    : iObserver( aObserver )

    {

    __ASSERT_DEBUG( iObserver, User::Invariant() );

    }

// -----------------------------------------------------------------------------

// CExprUDPMsg::NewL

// -----------------------------------------------------------------------------

//

CExprUDPMsg* CExprUDPMsg::NewL( MExpressionObserver* aObserver )

    {

    CExprUDPMsg* self = CExprUDPMsg::NewLC( aObserver );

    CleanupStack::Pop();

    return self;

    }

// -----------------------------------------------------------------------------

// CExprUDPMsg::NewLC

// -----------------------------------------------------------------------------

//

CExprUDPMsg* CExprUDPMsg::NewLC( MExpressionObserver* aObserver )

    {

    CExprUDPMsg* self = new( ELeave ) CExprUDPMsg( aObserver );

    CleanupStack::PushL( self );

    return self;

    }

// Destructor

CExprUDPMsg::~CExprUDPMsg()

    {

    }

// -----------------------------------------------------------------------------

// CExprUDPMsg::HandleReceivedDataL()

// -----------------------------------------------------------------------------

//

TBool CExprUDPMsg::HandleRecievedMsgL( TDes8& aData, TInt& aStartPos, TInt& aLength )

    {

    // Check if the prefix matches

    aStartPos = aData.Find( KUDPPrefix );

    if ( aStartPos != KErrNotFound  )

        {

        // Found a matching prefix

        // Let the observer know

        iObserver->FrameStarted();

        TPtr8 dataToParse( aData.MidTPtr( aStartPos ) );

        TInt err = TryParsingL( dataToParse, aLength );

        if ( err != KErrNone )

            {

            // corrupted data in the frame

            iObserver->ProtocolErrorL( err, aData );

            // delete the corrupted data

            aData.SetLength( 0 );

            }

        return ETrue;

        }

    else

        {

        return EFalse;

        }

    }

// -----------------------------------------------------------------------------

// CExprUDPMsg::TryParsingL

// -----------------------------------------------------------------------------

//

TInt CExprUDPMsg::TryParsingL( TDes8& aData, TInt& aLength )

    {

    __ASSERT_ALWAYS( aData.Left( KUDPPrefix().Length() ) == KUDPPrefix,

        User::Panic( _L("Protocol"), 1 ) );

    // UDP:0123,000e,[Some test data]

    TInt frameOverhead =

        KUDPPrefix().Length() +

        KHexDecimalLength +

        KPortSuffix().Length() +

        KHexDecimalLength +

        KLengthSuffix().Length() +

        KDataSuffix().Length() +

        KMessageSuffix().Length();

    if ( aData.Length() >= frameOverhead )

        {

        TPtrC8 portPtr(

            aData.Mid( KUDPPrefix().Length(), KHexDecimalLength ) );

        TLex8 portLexer( portPtr );

        TUint port;

        if ( portLexer.Val( port, EHex ) != KErrNone )

            {

            return KErrCorrupt;

            }

        DEBUG_PRINT( DEBUG_STRING( "CExprUDPMsg::TryParsingL, port = %d" ), port );

        //Check port suffix

        if ( aData.Mid( KUDPPrefix().Length() +

            KHexDecimalLength, KPortSuffix().Length() ) != KPortSuffix )

            {

            return KErrCorrupt;

            }

        TPtrC8 lengthPtr( aData.Mid( KUDPPrefix().Length() +

            KHexDecimalLength + KPortSuffix().Length(), KHexDecimalLength ) );

        TLex8 lengthLexer( lengthPtr );

        TUint length;

        if ( lengthLexer.Val( length, EHex ) != KErrNone )

            {

            return KErrCorrupt;

            }

        DEBUG_PRINT( DEBUG_STRING( "CExprUDPMsg::TryParsingL, length = %d" ), length );

        //Check length suffix

        if ( aData.Mid(

            KUDPPrefix().Length() +

            KHexDecimalLength +

            KPortSuffix().Length() +

            KHexDecimalLength, KLengthSuffix().Length() ) != KLengthSuffix )

            {

            return KErrCorrupt;

            }

        DEBUG_PRINT( DEBUG_STRING( "CExprUDPMsg::TryParsingL, parsing data" ), length );

        if ( aData.Length() >= TInt( frameOverhead + length ) )

            {

            TInt messagePos = KUDPPrefix().Length() +

                KHexDecimalLength +

                KPortSuffix().Length() +

                KHexDecimalLength +

                KLengthSuffix().Length();

            TPtrC8 message( aData.Mid( messagePos, length ) );

            if ( aData.Mid( messagePos + length,

                KDataSuffix().Length() ) != KDataSuffix )

                {

                return KErrCorrupt;

                }

            DEBUG_PRINT( DEBUG_STRING( "CExprUDPMsg::TryParsingL, message OK" ) );

            if ( aData.Mid( messagePos + length + KDataSuffix().Length(),

                KMessageSuffix().Length() ) != KMessageSuffix )

                {

                return KErrCorrupt;

                }

            // send parsed results

            iObserver->FrameParsedL( port, message );

            // set the length of the handled message

            aLength = frameOverhead + length;

            return KErrNone;

            }

        }

    return KErrNone;

    }

//  End of File