/*

* Copyright (c) 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:  This is a class, responsible of keeping track of existing presets

*               and their indexes.

*

*

*/

#ifndef CCENREPBOOKKEEPING_H_

#define CCENREPBOOKKEEPING_H_

#include <e32base.h>

class RWriteStream;

class RReadStream;

const TInt KMaxNumberOfPresetStations = 100;  // One temporarily used for internal book keeping

#define  LENGTHOFUSEDINDEXLWORDSARRAY ((KMaxNumberOfPresetStations/32) + 1)

/**

 *  it is a class, responsible of keeping track of existing presets and their indexes.

 */

NONSHARABLE_CLASS( CCenrepBookKeeping ) : public CBase

{

public:

    /**

    * Default class constructor.

    */

    CCenrepBookKeeping();

    /**

    * Destructor of CCenrepBookKeeping class.

    */

    ~CCenrepBookKeeping();

    /**

    * Get the current number of presets.

    * @return The number of presets.

    */

    TInt PresetCount() const;

    /**

    * Get the index of first preset.

    * @return The first preset index.

    */        

    TInt FirstIndex() const;

    /**

    * Get the index of the next preset.

    * @param aFromIndex -  Start from index after this.

    * @return the next preset index.

    */           

    TInt NextIndex( TInt aFromIndex = 0 );

    /**

    * Find an unused preset index.

    * @return Allocated index.

    */           

    TInt FindUnusedIndex() const;

    /**

    * Check if given index is used.

    * @return ETrue if used, otherwise EFalse 

    */           

    TBool IsIndexUsed( const TInt aIndex );

    /**

    * Add a preset.

    * @param aIndex -  Proposed index.

    * @return Used/Allocated index.

    */           

    void AddIndex( const TInt aIndex );

    /**

    * Remove a preset.

    * @param aIndex -  Index of the preset to be removed.

    * @return Used/Allocated index.

    */           

    void RemoveIndex( const TInt aIndex );

    /**

    * Clear all data.

    * @return The first preset index.

    */

    void Clear();

    /**

    * Gives descriptor pointer to bookkeeping's data.

    * @return TPtr8 Descriptor that contains bookkeeping data.

    */

    TPtr8 BookKeepingData();

private:

    // This data is copied to Central Repository Key (buffer) as such without

    // actual serialization.

    // Therefore in order to keep backward incombatibility don't

    // change the order of fields. Only the last array field can be allowed to grow.

    // If a new field is added to the end, the preceding array field cannot grow anymore.

    // Additionally the size of this structure should never shrink.

    class TBookKeepingData 

    {

    public:

        TInt iCount;    

        TUint32 iUsedIndexLWords[ LENGTHOFUSEDINDEXLWORDSARRAY ];

    } iBookKeepingData;

};

#endif // CCENREPBOOKKEEPING_H_