/*

* Copyright (c) 2002 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:  Define CCalcHistory class. This class is handled historical 

*                line of Calculator. 

*

*/

#ifndef     CALCHISTORY_H

#define     CALCHISTORY_H

//  INCLUDES

#include   <e32base.h>

//  CONSTANTS  

const TInt KCalcMaxHistoryLines(100);

//  FORWARD DECLARATIONS

class TCalcEditLine;

//  CLASS DEFINITIONS 

/**

CCalcHistory handles historical line of the calculator. 

*/

class   CCalcHistory :

        public CBase

    {

    public:  // Constructors and destructor

        /**

        * C++ default constructor.

        */

        CCalcHistory();

        /**

        * Destructor.

        */

        virtual ~CCalcHistory();

    public:     // New functions

        /**

        * Return (aIndex + 1)th latest history line.

        * @param aIndex  

        * @return (aIndex + 1)th latest history line.

        */

        const TCalcEditLine& operator[](TInt aIndex);  

        /**

        * Return count of historical lines. 

        * @return Count of historical lines

        */

        TInt Count() const;

        /**

        * Add newest history line

        * @param aLine : added line  

        */

        void Add(const TCalcEditLine aLine); 

        /**

        * Clear calculation history.

        */

        void ClearHistory();

        /**

        * Notify changing decimal separator.

        * @param aOld : Old decimal separator

        * @param aNew : New decimal separator  

        */

        void NotifyChangeDecimal(TChar aOld, TChar aNew);

    private:    // New functions

    private:    // Data

        //

        //  historical data

        //  Newest data index is iNewestIndex.

        //  

        //  <Case that iCount is smaller than KCalcMaxHistoryLines>

        //    As data is older, index is smaller. The oldest dara index is zero.

        //

        //  <Case that iCount is KCalcMaxHistoryLines>

        //    As data is older, index is smaller. But previous data index

        //   to index zero is KCalcMaxHistoryLines-1. previous index to

        //   KCalcMaxHistoryLines-1 is KCalcMaxHistoryLines-2. ..... 

        //   Therefore the oldest data index is iNewestIndex+1.

        //

        TCalcEditLine iHistory[KCalcMaxHistoryLines]; // Calculation history

        TInt      iCount;  // Valid historical lines

        TInt      iNewestIndex;  // Index of newest history

    };

#endif      //  CALCHISTORY_H

// End of File