Fixed entry searching algorithm to handle sequential same values

(Closes #1482)
ChartsOrg · Sep 21, 2016 · c4480ef · c4480ef
1 parent 95ea820
commit c4480ef
Showing 1 changed file with 24 additions and 4 deletions.
diff --git a/Source/Charts/Data/Implementations/Standard/ChartDataSet.swift b/Source/Charts/Data/Implementations/Standard/ChartDataSet.swift
@@ -298,17 +298,37 @@ open class ChartDataSet: ChartBaseDataSet
         {
             let m = (low + high) / 2
 
-            let d1 = abs(_values[m].x - xValue)
-            let d2 = abs(_values[m + 1].x - xValue)
+            let d1 = _values[m].x - xValue
+            let d2 = _values[m + 1].x - xValue
+            let ad1 = abs(d1), ad2 = abs(d2)
 
-            if d2 <= d1
+            if ad2 < ad1
             {
+                // [m + 1] is closer to xValue
+                // Search in an higher place
                 low = m + 1
             }
-            else
+            else if ad1 < ad2
             {
+                // [m] is closer to xValue
+                // Search in a lower place
                 high = m
             }
+            else
+            {
+                // We have multiple sequential x-value with same distance
+
+                if d1 >= 0.0
+                {
+                    // Search in a lower place
+                    high = m
+                }
+                else if d1 < 0.0
+                {
+                    // Search in an higher place
+                    low = m + 1
+                }
+            }
         }
 
         if high != -1