Added Ability to read interpolated Values from PI

Author: clackner-gpa

Source/Libraries/Adapters/PIAdapters/PIBufferInputAdapter.cs

@@ -231,17 +231,21 @@ private void GetPIConnection()
             m_connection.Open();
     }
 
-    private IEnumerable<AFValue> ReadData(AFTime startTime, AFTime endTime, PIPointList points)
+    private IEnumerable<AFValue> ReadData(AFTime startTime, AFTime endTime, PIPointList points, int sampleRate)
     {
-        return new TimeSortedValueScanner
-            {
-                Points = points,
-                StartTime = startTime,
-                EndTime = endTime,
-                DataReadExceptionHandler = ex => OnProcessException(MessageLevel.Warning, ex)
-            }
-            .Read(PageFactor);
-    }
+        TimeSortedValueScanner scanner = new TimeSortedValueScanner
+        {
+            Points = points,
+            StartTime = startTime,
+            EndTime = endTime,
+            DataReadExceptionHandler = ex => OnProcessException(MessageLevel.Warning, ex)
+        };
+
+        if (sampleRate <= 0)
+            return scanner.Read(PageFactor);
+        else
+            return scanner.ReadInterpolated(new AFTimeSpan(new TimeSpan(0,0,sampleRate)), PageFactor);
+     }
 
 
     /// <summary>
@@ -251,7 +255,7 @@ private IEnumerable<AFValue> ReadData(AFTime startTime, AFTime endTime, PIPointL
     /// <param name="end">The end time for the data requested.</param>
     /// <param name="tags">The list of PI Tags of the data requested separated by ;.</param>
     /// <returns>A string representing the read buffer data as comma-separated values in form tag:data1,time1;data2,time2 \newLine</returns>
-    public string ReadBuffer(DateTime start, DateTime end, string tags)
+    public string ReadBuffer(DateTime start, DateTime end, string tags, int interpolationInterval)
     {
         if (start.Kind == DateTimeKind.Unspecified)
             start = DateTime.SpecifyKind(start, DateTimeKind.Utc);
@@ -294,7 +298,7 @@ public string ReadBuffer(DateTime start, DateTime end, string tags)
         m_startTime = start < DateTime.MinValue ? DateTime.MinValue : start > DateTime.MaxValue ? DateTime.MaxValue : start;
         m_stopTime = end < DateTime.MinValue ? DateTime.MinValue : end > DateTime.MaxValue ? DateTime.MaxValue : end;
 
-        m_dataReader = ReadData(m_startTime, m_stopTime, points).GetEnumerator();
+        m_dataReader = ReadData(m_startTime, m_stopTime, points, interpolationInterval).GetEnumerator();
 
         while (m_dataReader.MoveNext())
         {
@@ -316,6 +320,7 @@ public string ReadBuffer(DateTime start, DateTime end, string tags)
             tagList.Select(item => $"{item.Key}:{string.Join(";", item.Value.Select(v => $"{v.Item2},{v.Item1}"))}"));
     }
 
+    
     /// <inheritdoc/>
     protected override void AttemptConnection() {}
 

Source/Libraries/Adapters/PIAdapters/TimeSortedValueScanner.cs

@@ -165,5 +165,112 @@ public IEnumerable<AFValue> Read(int pageFactor = 1)
         while (enumerators.Count > 0);
     }
 
+    /// <summary>
+    /// Reads all <see cref="AFValue"/> instances in time sorted order as a yielding enumerable using PI InterpolatedValues API.
+    /// </summary>
+    /// <param name="pageFactor">Defines a paging factor used to load more data into a page.</param>
+    /// <param name="interval">Defines the interval used for interpolation.</param>
+    /// <returns>Each recorded <see cref="AFValue"/> in time-sorted order for the specified <see cref="Points"/> and time-range.</returns>
+    /// 
+    public IEnumerable<AFValue> ReadInterpolated(AFTimeSpan interval, int pageFactor = 1)
+    {
+        PIPagingConfiguration config = new(PIPageType.TagCount, Points.Count * pageFactor < 1 ? 1 : pageFactor);
+        List<IEnumerator<AFValue>> enumerators = [];
+
+        try
+        {
+            // Setup enumerators for each set of points that have data
+            foreach (AFValues scanner in Points.InterpolatedValues(new AFTimeRange(StartTime, EndTime), interval,  null, false, config))
+            {
+                IEnumerator<AFValue> enumerator = scanner.GetEnumerator();
+
+                // Add enumerator to the list if it has at least one value
+                if (enumerator.MoveNext())
+                    enumerators.Add(enumerator);
+            }
+        }
+        catch (OperationCanceledException)
+        {
+            // Errors that occur during bulk calls get trapped here, actual error is stored on the PIPagingConfiguration object
+            DataReadExceptionHandler(config.Error);
+        }
+        catch (Exception ex)
+        {
+            DataReadExceptionHandler(ex);
+        }
+
+        if (enumerators.Count == 0)
+            yield break;
+
+        List<int> completed = [];
+
+        // Start publishing data points in time-sorted order
+        do
+        {
+            AFTime publishTime = AFTime.MaxValue;
+            AFValue dataPoint;
+
+            // Find minimum publication time for current values
+            foreach (IEnumerator<AFValue> enumerator in enumerators)
+            {
+                dataPoint = enumerator.Current;
+
+                if (dataPoint?.Timestamp < publishTime)
+                    publishTime = dataPoint.Timestamp;
+            }
+
+            int index = 0;
+
+            // Publish all values at the current time
+            foreach (IEnumerator<AFValue> enumerator in enumerators)
+            {
+                bool enumerationComplete = false;
+                dataPoint = enumerator.Current;
+
+                if (dataPoint?.Timestamp <= publishTime)
+                {
+                    // Attempt to advance to next data point, tracking completed enumerators
+                    if (!enumerator.MoveNext())
+                    {
+                        enumerationComplete = true;
+                        completed.Add(index);
+                    }
+
+                    yield return dataPoint;
+
+                    // Make sure any point IDs with duplicated times directly follow
+                    if (!enumerationComplete)
+                    {
+                        while (enumerator.Current?.Timestamp <= publishTime)
+                        {
+                            yield return enumerator.Current;
+
+                            if (!enumerator.MoveNext())
+                            {
+                                completed.Add(index);
+                                break;
+                            }
+                        }
+                    }
+                }
+
+                index++;
+            }
+
+            if (completed.Count == 0)
+                continue;
+
+            // Remove completed enumerators
+            completed.Sort();
+
+            for (int i = completed.Count - 1; i >= 0; i--)
+                enumerators.RemoveAt(completed[i]);
+
+            completed.Clear();
+        }
+        while (enumerators.Count > 0);
+    }
+
+
     #endregion
 }