/*

* Copyright (c) 2005 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:  An example implementation for ISC Driver Reference

*

*/

// INCLUDE FILES

#include <kernel.h>

#ifdef __WINS__

#include <windows.h>

#endif

#include <IscDefinitions.h>

#include "IscQueue.h"

#include "IscTrace.h"

// EXTERNAL DATA STRUCTURES

#ifdef __WINS__

extern CRITICAL_SECTION g_IscCriticalSection;

#endif

// EXTERNAL FUNCTION PROTOTYPES  

// CONSTANTS

const TInt KIscInterruptLevelTwo( 2 );

// MACROS

// LOCAL CONSTANTS AND MACROS

// MODULE DATA STRUCTURES

// LOCAL FUNCTION PROTOTYPES

// FORWARD DECLARATIONS

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

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

// DIscQueue::DIscQueue

// C++ default constructor 

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

//

DIscQueue::DIscQueue()

    :iHead( 0 ),iTail( 0 ),iCount( 0 ),iSize( 0 ),iQueue( NULL )

    {

    }

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

// DIscQueue::DIscQueue

// C++ default constructor can NOT contain any code, that

// might leave.

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

//

EXPORT_C DIscQueue::DIscQueue( TUint32** aQueue, TUint16 Size )

        :iHead( 0 ),iTail( 0 ),iCount( 0 ),iSize( Size ),iQueue( aQueue )

    {

    E_TRACE( ( _T( "IQ:IQ %d 0x%x" ), iSize, iQueue ) );

    }

// Destructor

EXPORT_C DIscQueue::~DIscQueue()

    {

    iHead   = 0;

    iTail   = 0;

    iCount  = 0;

    iQueue  = NULL;

    iSize   = 0;

    }

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

// DIscQueue::Add

// Function to add element to queue

// ( other items were commented in a header ).

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

//

EXPORT_C TInt DIscQueue::Add( TAny* anEntry )

    {

    E_TRACE( ( _T( "IQ:A %d 0x%x" ), iCount, iQueue ) );

    TInt irqLevel = DisableIrqs();

    if ( iCount == iSize || iSize == 0 )

        {

        RestoreIrqs( irqLevel );

        return KErrNoMemory;//EFalse;

        }

    /* place the buffer into the queue */

    iQueue[ iTail ] = ( TUint32* )( anEntry );

    if ( iSize > 0 )

        {

        /* adjust tail pointer */

        iTail = ++iTail % iSize;

        /* remember the amount of the requests in the queue */

        iCount++;

        }

    else

        {

        ASSERT_RESET_ALWAYS( 0, "IscDriver", EIscBufferAllocationFailure )

        }

    RestoreIrqs( irqLevel );

    return KErrNone;

    }

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

// DIscQueue::Remove

// Removes first element from the queue

// ( other items were commented in a header ).

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

//

EXPORT_C TAny* DIscQueue::RemoveFirst()

    {

    E_TRACE( ( _T( "IQ:R %d %d" ), iCount, iSize ) );

    TAny* result = NULL;

    TInt irqLevel = DisableIrqs();

    if ( iCount == 0 || iSize == 0 )

        {

        RestoreIrqs( irqLevel );

        return NULL;

        }

    // Get an element from the queue.

    result = ( TAny* )iQueue[ iHead ];

    iQueue[ iHead ] = NULL;

    // Adjust the head of the queue.

    iHead = ++iHead % iSize;

    // Decrease counter.

    iCount--;

    RestoreIrqs( irqLevel );

    return result;

    }

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

// DIscQueue::GetFirst

// Fetches first element from the queue

// ( other items were commented in a header ).

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

//

EXPORT_C TAny* DIscQueue::GetFirst()

    {

    E_TRACE( ( _T( "IQ:G %d %d" ), iCount, iSize ) );

    TAny* result;

    TInt irqLevel = DisableIrqs();

    if ( iCount == 0 || iSize == 0 )

        {

        RestoreIrqs( irqLevel );

        return NULL;

        }

    // Get an element from the queue.

    result = ( TAny* )iQueue[ iHead ];

    RestoreIrqs( irqLevel );

    return result;

    }

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

// DIscQueue::DeleteFirst

// Deletes first element from the queue

// ( other items were commented in a header ).

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

//

EXPORT_C void DIscQueue::DeleteFirst()

    {

    E_TRACE( ( _T( "IQ:D %d %d" ), iCount, iSize ) );

    TInt irqLevel = DisableIrqs();

    iQueue[ iHead ] = NULL;

    if ( iSize > 0 )

        {

        // Adjust the head of the queue.

        iHead = ++iHead % iSize;

        // decrease counter.

        iCount--;

        }

    else

        {

        ASSERT_RESET_ALWAYS( 0, "IscDriver", EIscBufferAllocationFailure )

        }

    RestoreIrqs( irqLevel );

    }

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

// DIscQueue::Empty

// Checks if queue is empty

// ( other items were commented in a header ).

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

//

EXPORT_C TBool DIscQueue::Empty()

    {

    TInt result;

    TInt irqLevel = DisableIrqs();

    result = iCount == 0 ? ETrue : EFalse;

    RestoreIrqs( irqLevel );

    return result;

    }

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

// DIscQueue::NextBufferLenth

// Gets length of next frame in queue

// ( other items were commented in a header ).

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

//

EXPORT_C TUint16 DIscQueue::NextBufferLength()

    {

    TUint16 length;

    TInt irqLevel = DisableIrqs();

    if ( iCount == 0 )

        {

        RestoreIrqs( irqLevel );

        return 0;

        }    

    length = ( TUint16 )( ( ( TDes8* )iQueue[ iHead ] )->Length() );    

    RestoreIrqs( irqLevel );

    return length;

    }

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

// DIscQueue::DisableIrqs

// Function to disable interrupts

// ( other items were commented in a header ).

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

//

TInt DIscQueue::DisableIrqs()

    {

#ifndef __WINS__

    return NKern::DisableInterrupts( KIscInterruptLevelTwo );

#else //__WINS__

    EnterCriticalSection( &g_IscCriticalSection );

    return KErrNone;

#endif//__WINS__

    }

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

// DIscQueue::RestoreIrqs

// Function to restore interrupts

// ( other items were commented in a header ).

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

//

#ifndef __WINS__

void DIscQueue::RestoreIrqs( 

    TInt aLevel )

    {

    NKern::RestoreInterrupts( aLevel );

#else //__WINS__

void DIscQueue::RestoreIrqs( 

    TInt )

{

    LeaveCriticalSection( &g_IscCriticalSection );

#endif//__WINS__

    }

//  End of File