// Copyright (c) 2004-2009 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\euser\cbase\ub_tque.cpp

// 

//

#include <e32std.h>

#include <e32std_private.h>

// Class TTickCountQue

/**

@internalComponent

@released

Constructs an empty list header

*/

TTickCountQue::TTickCountQue()

	{}

/**

@internalComponent

@released

Adds the specified list element.

The element is added into the list in order of its tick count.

@param aRef The list element to be inserted.

*/

void TTickCountQue::Add(TTickCountQueLink& aRef)

	{

	TTickCountQueLink* currentLink = (TTickCountQueLink*)(iHead.iNext);

	TTickCountQueLink* addLink = &aRef;

	while (	(currentLink != (TTickCountQueLink*)&iHead) &&

			(((TInt)(addLink->iTickCount - currentLink->iTickCount)) >= 0)

		)

		{

		currentLink = (TTickCountQueLink*)currentLink->iNext;

		}

	addLink->Enque(currentLink->iPrev);

	}

/**

@internalComponent

@released

Removes the first list element from the linked list if its tick count

is prior to the current tick count.

@param aTickCount The current tick count.

@return A pointer to the element removed from the linked list. This is NULL 

        if the first element has yet to expire or the queue is empty.

*/

TTickCountQueLink* TTickCountQue::RemoveFirst(TUint aTickCount)

	{

	TTickCountQueLink* firstLink = (TTickCountQueLink*)iHead.iNext;

	if (((TInt)(firstLink->iTickCount - aTickCount)) <= 0)

		{

		return RemoveFirst();

		}

	else

		{

		return NULL;

		}

	}

/**

@internalComponent

@released

Removes the first list element from the linked list, if any.

@return A pointer to the element removed from the linked list. This is NULL, 

        if the queue is empty.

*/

TTickCountQueLink* TTickCountQue::RemoveFirst()

	{

	TTickCountQueLink* firstLink = (TTickCountQueLink*)iHead.iNext;

	if (firstLink != (TTickCountQueLink*)&iHead)

		{

		firstLink->Deque();

		return firstLink;

		}

	return NULL;

	}

/**

@internalComponent

@released

Gets a pointer to the first list element in the doubly linked list.

@return A pointer to the first list element in the doubly linked list. If 

        the list is empty, this pointer is not necessarily NULL and must not

		be assumed to point to a valid object.

*/

TTickCountQueLink* TTickCountQue::First() const

	{

#if defined (_DEBUG)

	__DbgTestEmpty();

#endif

    return((TTickCountQueLink*)iHead.iNext);

    }