Ref T297, calculate ts differences ITimestampObjectList::getTimestampDifferenceMinMaxMean

src/blackmisc/timestampbased.h

@@ -49,6 +49,15 @@ namespace BlackMisc
         //! Time difference in ms
         qint64 getTimeDifferenceMs(qint64 compareTime) const { return compareTime - this->getMSecsSinceEpoch(); }
 
+        //! Time difference in ms
+        qint64 getTimeDifferenceMs(const ITimestampBased &compare) const { return compare.getMSecsSinceEpoch() - this->getMSecsSinceEpoch(); }
+
+        //! Time difference in ms
+        qint64 getAbsTimeDifferenceMs(qint64 compareTime) const { return qAbs(this->getTimeDifferenceMs(compareTime)); }
+
+        //! Time difference in ms
+        qint64 getAbsTimeDifferenceMs(const ITimestampBased &compare) const { return qAbs(this->getTimeDifferenceMs(compare)); }
+
         //! Set to null
         void setTimestampToNull();
 

src/blackmisc/timestampobjectlist.cpp

@@ -37,6 +37,7 @@
 #include <limits>
 #include <iterator>
 #include <type_traits>
+#include <numeric>
 
 using namespace BlackConfig;
 
@@ -330,6 +331,45 @@ namespace BlackMisc
         }
     }
 
+    template<class OBJ, class CONTAINER>
+    MillisecondsMinMaxMean ITimestampObjectList<OBJ, CONTAINER>::getTimestampDifferenceMinMaxMean() const
+    {
+        MillisecondsMinMaxMean mmm;
+        mmm.reset();
+        if (this->container().size() < 2) { return mmm; }
+
+        if (m_tsSortHint == NoTimestampSortHint)
+        {
+            CONTAINER copy(this->container());
+            copy.sortLatestFirst();
+            copy.m_tsSortHint = TimestampLatestFirst;
+            return copy.getTimestampDifferenceMinMaxMean();
+        }
+
+        mmm.max = std::numeric_limits<qint64>::min();
+        mmm.min = std::numeric_limits<qint64>::max();
+        qint64 mean = 0;
+        int c = 0;
+        OBJ last;
+
+        for (const OBJ &object : this->container())
+        {
+            c++;
+            last = object;
+            if (c < 2) { continue; }
+
+            const ITimestampBased &l = last;
+            const ITimestampBased &o = object;
+            const qint64 diff = l.getAbsTimeDifferenceMs(o);
+            if (diff > mmm.max) { mmm.max  = diff; }
+            if (diff < mmm.min) { mmm.min = diff;  }
+            mean += diff;
+        }
+
+        mmm.mean = mean / c;
+        return mmm;
+    }
+
     template <class OBJ, class CONTAINER>
     void ITimestampWithOffsetObjectList<OBJ, CONTAINER>::sortAdjustedLatestFirst()
     {

src/blackmisc/timestampobjectlist.h

@@ -21,6 +21,23 @@ class QDateTime;
 
 namespace BlackMisc
 {
+    //! Milliseconds minimum/maximum/mean
+    struct MillisecondsMinMaxMean
+    {
+        qint64 min;  //!< Minimum
+        qint64 max;  //!< Maximum
+        double mean; //!< Mean (average)
+
+        //! Valid?
+        bool isValid() const { return min >= 0 && max >= 0; }
+
+        //! Reset the values
+        void reset() { min = -1; max = -1; mean = -1;}
+
+        //! As string
+        QString asString() const { static const QString s("Min: %1 Max: %2 Mean: %3"); return s.arg(min).arg(max).arg(mean, 0, 'f', 2); }
+    };
+
     //! List of objects with timestamp.
     //! Such objects should implement \sa ITimestampBased
     template<class OBJ, class CONTAINER> class ITimestampObjectList
@@ -30,7 +47,8 @@ namespace BlackMisc
         enum HintTimestampSort
         {
             NoTimestampSortHint,
-            TimestampLatestFirst
+            TimestampLatestFirst,
+            TimestampLatestLast
         };
 
         //! List of objects before dateTime (older)
@@ -125,6 +143,10 @@ namespace BlackMisc
         //! Adds a time to all values
         void addMsecs(qint64 msToAdd);
 
+        //! Difference of timestamp values
+        //! \cond timestamp list has to be sorted to get meaninful values
+        MillisecondsMinMaxMean getTimestampDifferenceMinMaxMean() const;
+
         //! Set the hint
         void setSortHint(HintTimestampSort hint) { m_tsSortHint = hint; }