Re #6152. Fix if-else construct that was identical on either branch.

There's also a slight change in behaviour. If a 'good' region contains
more than one log value, and log values are considered to represent the
left of a bin, then the end time will be the point it went 'bad'
(previously it was the time of the last good value + a tolerance).

Code/Mantid/Framework/Kernel/inc/MantidKernel/TimeSeriesProperty.h

@@ -166,7 +166,7 @@ namespace Mantid
       /// Split out a time series property by time intervals.
       void splitByTime(TimeSplitterType& splitter, std::vector< Property * > outputs) const;
       /// Fill a TimeSplitterType that will filter the events by matching
-      void makeFilterByValue(TimeSplitterType& split, TYPE min, TYPE max, double TimeTolerance, bool centre=true);
+      void makeFilterByValue(TimeSplitterType& split, TYPE min, TYPE max, double TimeTolerance, bool centre=true) const;
 
       ///  Return the time series as a correct C++ map<DateAndTime, TYPE>. All values
       std::map<DateAndTime, TYPE> valueAsCorrectMap() const;

Code/Mantid/Framework/Kernel/src/TimeSeriesProperty.cpp

@@ -448,32 +448,33 @@ namespace Mantid
      * @param centre :: Whether the log value time is considered centred or at the beginning.
      */
     template<typename TYPE>
-    void TimeSeriesProperty<TYPE>::makeFilterByValue(TimeSplitterType& split, TYPE min, TYPE max, double TimeTolerance, bool centre)
+    void TimeSeriesProperty<TYPE>::makeFilterByValue(TimeSplitterType& split, TYPE min, TYPE max, double TimeTolerance, bool centre) const
     {
+      // Make sure the splitter starts out empty
+      split.clear();
+
       //Do nothing if the log is empty.
-      if (m_values.size() == 0)
-        return;
+      if ( m_values.empty() ) return;
 
       // 1. Sort
       sort();
 
       // 2. Do the rest
-      bool lastGood = false;
-      bool isGood;
+      bool lastGood(false);
       time_duration tol = DateAndTime::durationFromSeconds( TimeTolerance );
       int numgood = 0;
-      DateAndTime lastTime, t;
+      DateAndTime t;
       DateAndTime start, stop;
 
-      for (size_t i = 0; i < m_values.size(); i ++)
+      for (size_t i = 0; i < m_values.size(); ++i)
       {
-        lastTime = t;
+        const DateAndTime lastTime = t;
         //The new entry
         t =m_values[i].time();
         TYPE val = m_values[i].value();
 
         //A good value?
-        isGood = ((val >= min) && (val < max));
+        const bool isGood = ((val >= min) && (val < max));
         if (isGood)
           numgood++;
 
@@ -492,18 +493,18 @@ namespace Mantid
           else
           {
             //End of the good section
-            if (numgood == 1)
+            if (numgood == 1 || centre )
             {
-              //There was only one point with the value. Use the last time, + the tolerance, as the end time
+              // If there was only one point with the value, or values represent bin centres,
+              // use the last good time, + the tolerance, as the end time
               stop = lastTime + tol;
-              split.push_back( SplittingInterval(start, stop, 0) );
             }
             else
             {
-              //At least 2 good values. Save the end time
-              stop = lastTime + tol;
-              split.push_back( SplittingInterval(start, stop, 0) );
+              // At least 2 good values for left boundary aligned logs. Save the end time.
+              stop = t;
             }
+            split.push_back( SplittingInterval(start, stop, 0) );
             //Reset the number of good ones, for next time
             numgood = 0;
           }
@@ -516,7 +517,6 @@ namespace Mantid
         //The log ended on "good" so we need to close it using the last time we found
         stop = t + tol;
         split.push_back( SplittingInterval(start, stop, 0) );
-        numgood = 0;
       }
 
       return;

Code/Mantid/Framework/Kernel/test/TimeSeriesPropertyTest.h

@@ -344,6 +344,7 @@ class TimeSeriesPropertyTest : public CxxTest::TestSuite
 
     TS_ASSERT_EQUALS( log->realSize(), 6);
 
+    // Test centred log value boundaries
     TimeSplitterType splitter;
     log->makeFilterByValue(splitter, 1.8, 2.2, 1.0);
 
@@ -363,6 +364,24 @@ class TimeSeriesPropertyTest : public CxxTest::TestSuite
     t = DateAndTime("2007-11-30T16:17:41");
     TS_ASSERT_DELTA( s.stop(), t, 1e-3);
 
+
+    // Now test with left-aligned log value boundaries
+    log->makeFilterByValue(splitter, 1.8, 2.2, 1.0, false);
+
+    TS_ASSERT_EQUALS( splitter.size(), 2);
+
+    s = splitter[0];
+    t = DateAndTime("2007-11-30T16:17:10");
+    TS_ASSERT_DELTA( s.start(), t, 1e-3);
+    t = DateAndTime("2007-11-30T16:17:11");
+    TS_ASSERT_DELTA( s.stop(), t, 1e-3);
+
+    s = splitter[1];
+    t = DateAndTime("2007-11-30T16:17:30");
+    TS_ASSERT_DELTA( s.start(), t, 1e-3);
+    t = DateAndTime("2007-11-30T16:17:50");
+    TS_ASSERT_DELTA( s.stop(), t, 1e-3);
+
     delete log;
   }