altoslib: Avoid crashing when computing stats for empty flight logs

[fw/altos] / altoslib / AltosTimeSeries.java

diff --git a/altoslib/AltosTimeSeries.java b/altoslib/AltosTimeSeries.java
index b3c432fcf565e1b481d63e0025024334a8d90061..9f3b4d807ef26bb36ae9a358515ac41c17f3bad5 100644 (file)
--- a/altoslib/AltosTimeSeries.java
+++ b/altoslib/AltosTimeSeries.java
@@ -151,11 +151,15 @@ public class AltosTimeSeries implements Iterable<AltosTimeValue>, Comparable<Alt
        }
 
        public AltosTimeValue first() {
-               return values.get(0);
+               if (values.size() > 0)
+                       return values.get(0);
+               return null;
        }
 
        public AltosTimeValue last() {
-               return values.get(values.size() - 1);
+               if (values.size() > 0)
+                       return values.get(values.size() - 1);
+               return null;
        }
 
        public double average() {