1 /*

     2 * Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description: 

    15 *

    16 */

    17 

    18 #ifndef BUFFERMANAGER_H_

    19 #define BUFFERMANAGER_H_

    20 

    21 class AbstractDataProvider

    22 {

    23 public:

    24 

    25     enum requestsOrder {

    26             ascending,

    27             descending

    28     };   

    29     

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

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

    32 };

    33 

    34 

    35 class BufferManager

    36 {

    37 public:    

    38     

    39 	BufferManager(

    40 	    AbstractDataProvider* aObserver,

    41 		int aBufferSize,

    42 		int aBufferTreshold,

    43 		int aInitialPosition,

    44 		int aTotalCount );

    45 

    46 	~BufferManager();

    47 

    48 	void setPosition( int aIndex );

    49 

    50 	void resetBuffer( int aPosition, int aTotalCount);

    51 

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

    53 	void resizeCache(int newSize, int newTreshold);

    54 	

    55 private:

    56 	void calculate();

    57 

    58 private:

    59     AbstractDataProvider* mObserver; 

    60     

    61 	int mBufferSize;

    62 	int mBufferTreshold;

    63 	int mBufferPosition;

    64 	int mDiff;

    65 	int mTotalCount;

    66 

    67 	bool mResetOrdered;

    68 

    69 	int mRequestStart;

    70 	int mRequestCount;

    71 	int mReleaseStart;

    72 	int mReleaseCount;

    73 };

    74 

    75 

    76 

    77 #endif /*BUFFERMANAGER_H_*/