// Copyright (c) 2005-2009 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:

// circular.h - Basic circluar list for IPSEC

// @internalComponent	for IPSEC

//

/**

 @internalComponent

*/

#ifndef __CIRCULAR_H__

#define __CIRCULAR_H__

#include <e32def.h>

class RCircularList

	/**

	* Circular list.

	*

	* This is a double linked list without a specific "head".

	* An element may be alone in it's list (both links point

	* to self). The list is never empty, it always includes

	* the object itself.

	*/

	{

public:

	RCircularList();

	~RCircularList();

	RCircularList(RCircularList &aList);

	void Attach(RCircularList &aList);

	void Detach();

	inline TBool IsDetached() const

		/**

		* Return ETrue if this is the only item in the list.

		*/

		{

		return iNext == this;

		}

	RCircularList *iPrev;	//< Previous in the ring (never NULL)

	RCircularList *iNext;	//< Next in the rign (never NULL)

	};

class TCircularListIter

	/**

	* Iterate over the objects in the list.

	*

	* The initial element in construction of the iterator is treated

	* as a traditional list head. The iterator gives the other objects

	* in the list (if any).

	*

	* If the initial element is alone in the ciruclar list, the

	* first application of ++ returns NULL (e.g. the list contains

	* the only the "head", which is never returned by this iterator).

	*/

	{

public:

	inline TCircularListIter(const RCircularList &aList) : iMark(aList), iNext(aList.iNext)

		/**

		* Construct iterator.

		*

		* @param aList	The head element.

		*/

		{}

	RCircularList* operator++(TInt);

private:

	const RCircularList &iMark;	//< The designated list "head" element.

	RCircularList *iNext; 		//< The next element to return with ++ (or "head", if at end of list).

	};

#endif