// Copyright (c) 2002-2009 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:
// e32\drivers\usbcc\queue.cpp
// Platform independent layer (PIL) of the USB Device controller driver:
// Simple singly linked list + its iterator.
// 
//

/**
 @file queue.cpp
 @internalTechnology
*/
//#include <drivers/usbc.h>
#include <usb/usbc.h>


void TSglQueLink::Enque(TSglQueLink* aLink)
//
// Enque this after aLink.
//
    {
    iNext = aLink->iNext;
    aLink->iNext = this;
    }


TSglQueBase::TSglQueBase(TInt aOffset)
//
// Constructor
//
    : iHead(NULL), iLast((TSglQueLink*) &iHead), iOffset(aOffset), iElements(0)
    {
    // ESQueOffsetNotAligned
    __ASSERT_ALWAYS((iOffset % 4 == 0), Kern::Fault(KUsbPILPanicCat, __LINE__));
    }


void TSglQueBase::DoAddLast(TAny* aPtr)
//
// Add the object at the end of the queue.
//
    {
    TSglQueLink* pL = PtrAdd((TSglQueLink*) aPtr, iOffset);
    pL->Enque(iLast);
    iLast = pL;
    iElements++;
    __ASSERT_DEBUG((iElements > 0), Kern::Fault(KUsbPILPanicCat, __LINE__));
    }


void TSglQueBase::DoRemove(TAny* aPtr)
//
// Remove the object from the queue.
//
    {
    TSglQueLink* pP = (TSglQueLink*) (&iHead);
    TSglQueLink* pL = PtrAdd((TSglQueLink*) aPtr, iOffset);
    TSglQueLink* pN = pP->iNext;
    while (pN)
        {
        if (pN == pL)
            {
            pP->iNext = pN->iNext;
            if (iLast == pL)
                {
                iLast = pP;
                if (iLast == NULL)
                    iLast = (TSglQueLink*) (&iHead);
                }
            iElements--;
            __ASSERT_DEBUG((iElements >= 0), Kern::Fault(KUsbPILPanicCat, __LINE__));
            return;
            }
        pP = pN;
        pN = pP->iNext;
        }
    // This doesn't have to indicate an error (but might):
    __KTRACE_OPT(KPANIC, Kern::Printf("TSglQueBase::DoRemove: ESQueLinkNotQueued"));
    }


TSglQueIterBase::TSglQueIterBase(TSglQueBase& aQue)
//
// Constructor.
//
    : iOffset(aQue.iOffset), iHead(aQue.iHead), iNext(aQue.iHead)
    {
    }


void TSglQueIterBase::SetToFirst()
//
// Start from the beginning of the que.
//
    {
    iNext = iHead->iNext;
    }


TAny* TSglQueIterBase::DoPostInc()
//
// Return the current pointer and increment.
//
    {
    TAny* pN = iNext;
    if (pN == NULL)
        return NULL;
    iNext = iNext->iNext;
    return PtrSub(pN, iOffset);
    }


//---