--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/landmarks/locationlandmarks/localsearchprov/src/EPos_TPosLmProgressHelper.cpp	Tue Feb 02 01:06:48 2010 +0200
@@ -0,0 +1,167 @@
+/*
+* Copyright (c) 2005 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 helper class for calculating progress during a search operation.
+*
+*/
+
+
+// INCLUDE FILES
+#include <e32math.h>
+#include "EPos_TPosLmProgressHelper.h"
+
+// CONSTANTS
+const TInt KGuessNumOfEvaluatedRows = 16;
+const TInt KGuessNumOfEvaluatedRowsNoSearchCondition = 257;
+const TReal32 KTarget = 0.5;
+const TReal32 KPosNumOfEvalsMinLimit = 1.0;
+
+// ============================ MEMBER FUNCTIONS ===============================
+
+// -----------------------------------------------------------------------------
+// TPosLmProgressHelper::TPosLmProgressHelper
+// C++ default constructor can NOT contain any code, that
+// might leave.
+// -----------------------------------------------------------------------------
+//
+TPosLmProgressHelper::TPosLmProgressHelper()
+:   iEvalCounter(0),
+    iGuessNumOfEvalsDivByTwo(0),
+    iPreviousEvaluationProgress(0),
+    iEvaluationProgress(0),
+    iNumOfRowsInPreviousEvaluations(0),
+    iNumOfRowsInEvaluation(0),
+    iRowCounter(0)
+    {
+    }
+
+// -----------------------------------------------------------------------------
+// TPosLmProgressHelper::PrepareCalculateProgress
+//
+// (other items were commented in a header).
+// -----------------------------------------------------------------------------
+//
+void TPosLmProgressHelper::PrepareCalculateProgress(
+    TInt aNoOfRowsToEvaluate,
+    TBool aSqlQueryIncludesSearchCondition)
+    {
+    iEvalCounter = 0;
+
+    TInt guessNumOfEvaluatedRows = KGuessNumOfEvaluatedRows;
+    if (!aSqlQueryIncludesSearchCondition)
+        {
+        guessNumOfEvaluatedRows = KGuessNumOfEvaluatedRowsNoSearchCondition;
+        }
+
+    TReal32 guessNumOfEvals =
+        TReal32(aNoOfRowsToEvaluate) / TReal32(guessNumOfEvaluatedRows);
+
+    if (guessNumOfEvals < KPosNumOfEvalsMinLimit)
+        {
+        // We always need to evaluate the view at least one time.
+        guessNumOfEvals = KPosNumOfEvalsMinLimit;
+        }
+
+    iGuessNumOfEvalsDivByTwo = guessNumOfEvals * KTarget;
+    }
+
+// -----------------------------------------------------------------------------
+// TPosLmProgressHelper::HandleViewPrepared
+//
+// (other items were commented in a header).
+// -----------------------------------------------------------------------------
+//
+void TPosLmProgressHelper::HandleViewPrepared()
+    {
+    iNumOfRowsInPreviousEvaluations = 0;
+    iNumOfRowsInEvaluation = 0;
+    iRowCounter = 0;
+    }
+
+// -----------------------------------------------------------------------------
+// TPosLmProgressHelper::HandleViewEvaluatedL
+//
+// (other items were commented in a header).
+// -----------------------------------------------------------------------------
+//
+void TPosLmProgressHelper::HandleViewEvaluatedL(TInt aNumOfRowsInView)
+    {
+    iEvalCounter++;
+    iPreviousEvaluationProgress = iEvaluationProgress;
+    iEvaluationProgress = CalculateEvaluationProgressL();
+
+    iNumOfRowsInEvaluation = aNumOfRowsInView - iNumOfRowsInPreviousEvaluations;
+    iNumOfRowsInPreviousEvaluations = aNumOfRowsInView;
+    iRowCounter = 0;
+    }
+
+// -----------------------------------------------------------------------------
+// TPosLmProgressHelper::HandleViewGetRow
+//
+// (other items were commented in a header).
+// -----------------------------------------------------------------------------
+//
+void TPosLmProgressHelper::HandleViewGetRow()
+    {
+    iRowCounter++;
+    }
+
+// -----------------------------------------------------------------------------
+// TPosLmProgressHelper::CalculateProgressL
+//
+// (other items were commented in a header).
+// -----------------------------------------------------------------------------
+//
+TReal32 TPosLmProgressHelper::CalculateProgressL()
+    {
+    TReal32 progress = iEvaluationProgress;
+
+    if (iRowCounter != iNumOfRowsInEvaluation)
+        {
+        __ASSERT_DEBUG(iNumOfRowsInEvaluation != 0,
+            User::Leave(KErrDivideByZero));
+        progress = iPreviousEvaluationProgress +
+                   (iEvaluationProgress - iPreviousEvaluationProgress) *
+                   iRowCounter / iNumOfRowsInEvaluation;
+        }
+
+    return progress;
+    }
+
+// -----------------------------------------------------------------------------
+// TPosLmProgressHelper::CalculateEvaluationProgressL
+//
+// (other items were commented in a header).
+// -----------------------------------------------------------------------------
+//
+TReal32 TPosLmProgressHelper::CalculateEvaluationProgressL()
+    {
+    // The formula 1-2^(-steps/(guessed number of steps/2)) has the following
+    // characteristics:
+    // * After 0 steps, the progress is 0%
+    // * Progress increases for each step
+    // * After half the guessed number of steps, the progress is 50%
+    // * Progress will increase towards 100% but will never get there even if
+    //   the number of steps passes the guessed number of steps.
+
+    TReal target;
+    User::LeaveIfError(
+        Math::Pow(target,
+                  TReal(2),
+                  TReal(-(iEvalCounter / iGuessNumOfEvalsDivByTwo))));
+
+    return TReal32(1 - target);
+    }
+
+// End of File