/*

* 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: 

*

*/

#ifndef BUFFERMANAGER_H_

#define BUFFERMANAGER_H_

class AbstractDataProvider

{

public:

    enum requestsOrder {

            ascending,

            descending

    };   

    virtual void release(int start, int end) = 0;

    virtual void request(int start, int end, requestsOrder order) = 0;    

};

class BufferManager

{

public:    

	BufferManager(

	    AbstractDataProvider* aObserver,

		int aBufferSize,

		int aBufferTreshold,

		int aInitialPosition,

		int aTotalCount );

	~BufferManager();

	void setPosition( int aIndex );

	void resetBuffer( int aPosition, int aTotalCount);

	void itemCountChanged( int aIndex, bool aRemoved, int aNewTotalCount );

	void resizeCache(int newSize, int newTreshold);

private:

	void calculate();

private:

    AbstractDataProvider* mObserver; 

	int mBufferSize;

	int mBufferTreshold;

	int mBufferPosition;

	int mDiff;

	int mTotalCount;

	bool mResetOrdered;

	int mRequestStart;

	int mRequestCount;

	int mReleaseStart;

	int mReleaseCount;

};

#endif /*BUFFERMANAGER_H_*/