From 5d4ab7362037265c7b8040d8b1760ecd7ec236d5 Mon Sep 17 00:00:00 2001
From: Andrew Davie <andrew@taswegian.com>
Date: Wed, 30 Mar 2016 15:14:24 +1100
Subject: [PATCH] Edge cases handled gracefully for low point-count arrays

Sitations with low point-counts may have been problematic. Now, 0, 1 and 2 point arrays are explicitly handled.
Added a copy constructor to WptPt to allow copies to be made, rather than returning original array.
Cases where no data is returned always returns a zero-sized array rather than a null array.
---
 OsmAnd/src/net/osmand/plus/GPXUtilities.java  | 21 ++++++++++++++++
 .../plus/views/AsynchronousResampler.java     | 25 +++++++++++++------
 .../src/net/osmand/plus/views/Renderable.java |  1 +
 3 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/OsmAnd/src/net/osmand/plus/GPXUtilities.java b/OsmAnd/src/net/osmand/plus/GPXUtilities.java
index 68760bd836..8099f433d4 100644
--- a/OsmAnd/src/net/osmand/plus/GPXUtilities.java
+++ b/OsmAnd/src/net/osmand/plus/GPXUtilities.java
@@ -109,6 +109,27 @@ public class GPXUtilities {
 		public WptPt() {
 		}
 
+		public WptPt(WptPt toCopy) {
+			this.lat = toCopy.lat;
+			this.lon = toCopy.lon;
+			if (toCopy.name != null) {
+				this.name = new String(toCopy.name);
+			}
+			if (toCopy.link != null) {
+				this.link = new String(toCopy.link);
+			}
+			if (toCopy.category != null) {
+				this.category = new String(toCopy.category);
+			}
+			this.time = toCopy.time;
+			this.ele = toCopy.ele;
+			this.speed = toCopy.speed;
+			this.hdop = toCopy.hdop;
+			this.deleted = toCopy.deleted;
+			this.colourARGB = toCopy.colourARGB;
+			this.distance = toCopy.distance;
+		}
+
 		public void setDistance(double dist) {
 			distance = dist;
 		}
diff --git a/OsmAnd/src/net/osmand/plus/views/AsynchronousResampler.java b/OsmAnd/src/net/osmand/plus/views/AsynchronousResampler.java
index fbe46572d4..a7fbd8dcfc 100644
--- a/OsmAnd/src/net/osmand/plus/views/AsynchronousResampler.java
+++ b/OsmAnd/src/net/osmand/plus/views/AsynchronousResampler.java
@@ -16,7 +16,7 @@ public abstract class AsynchronousResampler extends AsyncTask<String,Integer,Str
 
     AsynchronousResampler(Renderable.RenderableSegment rs) {
         this.rs = rs;
-        culled = null;
+        culled = new ArrayList<>();     // so we NEVER return a null list
     }
 
     @Override protected void onPostExecute(String result) {
@@ -35,10 +35,10 @@ public abstract class AsynchronousResampler extends AsyncTask<String,Integer,Str
 
     protected List<GPXUtilities.WptPt> resampleTrack(List<GPXUtilities.WptPt> pts, double dist) {
 
-        ArrayList<GPXUtilities.WptPt> newPts = new ArrayList<>();
+        List<GPXUtilities.WptPt> newPts = new ArrayList<>();
 
         int ptCt = pts.size();
-        if (ptCt > 0) {
+        if (ptCt > 1) {
 
             GPXUtilities.WptPt lastPt = pts.get(0);
             double segSub = 0;
@@ -76,6 +76,11 @@ public abstract class AsynchronousResampler extends AsyncTask<String,Integer,Str
             GPXUtilities.WptPt newPoint = new GPXUtilities.WptPt( lastPt.getLatitude(), lastPt.getLongitude(), lastPt.time, lastPt.ele, lastPt.speed, lastPt. hdop);
             newPoint.setDistance(cumDist);
             newPts.add(newPts.size(), newPoint);
+
+        } else { // 0 and 1 point lines are just copied
+            for (GPXUtilities.WptPt pt : pts) {
+                newPts.add(new GPXUtilities.WptPt(pt));
+            }
         }
         return newPts;
     }
@@ -98,7 +103,7 @@ public abstract class AsynchronousResampler extends AsyncTask<String,Integer,Str
             // Resample track, then analyse altitudes and set colours for each point
 
             culled = resampleTrack(rs.getPoints(), segmentSize);
-            if (!isCancelled()) {
+            if (!isCancelled() && !culled.isEmpty()) {
 
                 int halfC = Algorithms.getRainbowColor(0.5);
 
@@ -138,7 +143,7 @@ public abstract class AsynchronousResampler extends AsyncTask<String,Integer,Str
 
             List<GPXUtilities.WptPt> points = rs.getPoints();
             culled = resampleTrack(points, segmentSize);
-            if (!isCancelled()) {
+            if (!isCancelled() && !culled.isEmpty()) {
 
                 GPXUtilities.WptPt lastPt = points.get(0);
                 lastPt.speed = 0;
@@ -211,10 +216,9 @@ public abstract class AsynchronousResampler extends AsyncTask<String,Integer,Str
             // Reduce the point-count of the GPX track using Ramer-Douglas-Peucker algorithm.
 
             points = rs.getPoints();
-            culled = new ArrayList<>();
-
             int nsize = points.size();
-            if (nsize > 0) {
+            if (nsize > 2) {
+                culled = new ArrayList<>();
                 survivor = new boolean[nsize];
                 cullRamerDouglasPeucer(0, nsize - 1);
                 if (!isCancelled()) {
@@ -224,6 +228,11 @@ public abstract class AsynchronousResampler extends AsyncTask<String,Integer,Str
                             culled.add(points.get(i));
                         }
                 }
+            } else { // make a copy of 0-1-2 point arrays
+                culled = new ArrayList<>();
+                for (GPXUtilities.WptPt pt : points) {
+                    culled.add(new GPXUtilities.WptPt(pt));
+                }
             }
             return isCancelled() ? "" : "OK";
         }
diff --git a/OsmAnd/src/net/osmand/plus/views/Renderable.java b/OsmAnd/src/net/osmand/plus/views/Renderable.java
index 684bc7e5e7..64b734fb4a 100644
--- a/OsmAnd/src/net/osmand/plus/views/Renderable.java
+++ b/OsmAnd/src/net/osmand/plus/views/Renderable.java
@@ -78,6 +78,7 @@ public class Renderable {
         // When the asynchronous task has finished, it calls this function to set the 'culled' list
         public void setRDP(List<GPXUtilities.WptPt> cull) {
 
+            assert cull!=null;
             culled = cull;
 
             // Find the segment's bounding box, to allow quick draw rejection later