--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ganeswidgets/inc/hgscrollbuffermanager.h	Thu Jun 24 12:59:29 2010 +0300
@@ -0,0 +1,133 @@
+/*
+* 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 HGSCROLLBUFFERMANAGER_H_
+#define HGSCROLLBUFFERMANAGER_H_
+
+#include <QObject>
+#include <QTimer>
+
+class UpdatePair
+{
+public:
+    UpdatePair(int start, int count);
+
+    int start() const;
+    int end() const;
+
+    bool adjacent(int start, int count) const;
+    bool contains(const UpdatePair &other) const;
+    void extend(int start, int count);
+    void subtract(int start, int count);
+
+    void shiftRight(int count);
+    void shiftLeft(int count);
+
+    bool operator== (const UpdatePair &other) const;
+    bool operator< (const UpdatePair &other) const;
+
+private:
+    int mStart;
+    int mCount;
+};
+
+class UpdateBuffer : public QList<UpdatePair>
+{
+public:
+    UpdateBuffer();
+
+    void add(int start, int count);
+    void remove(int start, int count);
+    void shiftRight(int startingFrom, int amount);
+    void shiftLeft(int startingFrom, int amount);
+};
+
+class HgScrollBufferManager: public QObject
+    {
+    Q_OBJECT
+public:
+
+    HgScrollBufferManager(
+            int bufferSize,
+            int bufferTreshold,
+            int initialPosition,
+            int totalCount);
+
+    virtual ~HgScrollBufferManager();
+
+    void resetBuffer(int aPosition, int aTotalCount);
+
+    void scrollPositionChanged(int newPosition);
+
+    bool positionInsideBuffer(int position);
+
+    void addItems(int start, int count);
+    void removeItems(int start, int end);
+    void moveItems(int start, int end, int target);
+
+    void flushRequestBuffers();
+
+    void currentBuffer(int& bufferStart, int& bufferEnd);
+
+signals:
+
+    void releaseItems(int releaseStart, int releaseEnd);
+    void requestItems(int requestStart, int requestEnd);
+
+protected slots:
+
+    void timeout();
+
+protected:
+
+    void init();
+    void asyncUpdate();
+
+    int changeBufferPosition(int newPos);
+
+    void simpleAddItems(int start, int end);
+    void simpleRemoveItems(int start, int end);
+
+    void appendRequestBuffer(int start, int end);
+    void appendReleaseBuffer(int start, int end);
+
+private:
+
+    int mBufferSize;
+    int mBufferTreshold;
+    int mBufferPosition;
+    int mDiff;
+    int mTotalCount;
+
+    bool mResetOrdered;
+
+    int mRequestStart;
+    int mRequestCount;
+    int mReleaseStart;
+    int mReleaseCount;
+    QTimer mTimer;
+    bool mFirstTime;
+    
+    UpdateBuffer mRequestBuffer;
+    UpdateBuffer mReleaseBuffer;
+    
+private:
+    Q_DISABLE_COPY(HgScrollBufferManager)
+    };
+
+#endif /*HGSCROLLBUFFERMANAGER_H_*/