From 39b49aadcad15902f31b188d2b0630e35b0702c2 Mon Sep 17 00:00:00 2001
From: Samuel Tardieu <sam@rfc1149.net>
Date: Sat, 26 Jan 2013 21:27:00 +0100
Subject: =?UTF-8?q?Do=20not=20use=20a=20N=C2=B2=20algorithm=20when=20mergi?=
 =?UTF-8?q?ng=20waypoints=20sets?=
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The prefix of a waypoint must be unique for a given cache, so use that
instead of the name for merging (the name needs not be unique).

Also, it won't break if we have duplicate prefixes in the old waypoints
list, those will be kept as well in the new list.
---
 main/src/cgeo/geocaching/Waypoint.java | 39 ++++++++++++++--------------------
 1 file changed, 16 insertions(+), 23 deletions(-)

diff --git a/main/src/cgeo/geocaching/Waypoint.java b/main/src/cgeo/geocaching/Waypoint.java
index 8209b32..1d88c40 100644
--- a/main/src/cgeo/geocaching/Waypoint.java
+++ b/main/src/cgeo/geocaching/Waypoint.java
@@ -8,7 +8,9 @@ import org.apache.commons.lang3.StringUtils;
 import android.content.res.Resources;
 import android.widget.TextView;
 
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 public class Waypoint implements IWaypoint, Comparable<Waypoint> {
 
@@ -82,29 +84,20 @@ public class Waypoint implements IWaypoint, Comparable<Waypoint> {
         }
     }
 
-    public static void mergeWayPoints(List<Waypoint> newPoints,
-            List<Waypoint> oldPoints, boolean forceMerge) {
-        // copy user modified details of the waypoints
-        if (newPoints != null && oldPoints != null) {
-            for (Waypoint old : oldPoints) {
-                if (old != null) {
-                    boolean merged = false;
-                    if (StringUtils.isNotEmpty(old.name)) {
-                        for (Waypoint waypoint : newPoints) {
-                            if (waypoint != null && waypoint.name != null) {
-                                if (old.name.equalsIgnoreCase(waypoint.name)) {
-                                    waypoint.merge(old);
-                                    merged = true;
-                                    break;
-                                }
-                            }
-                        }
-                    }
-                    // user added waypoints should also be in the new list
-                    if (!merged && (old.isUserDefined() || forceMerge)) {
-                        newPoints.add(old);
-                    }
-                }
+    public static void mergeWayPoints(final List<Waypoint> newPoints, final List<Waypoint> oldPoints, final boolean forceMerge) {
+        // Build a map of new waypoints for faster subsequent lookups
+        final Map<String, Waypoint> newPrefixes = new HashMap<String, Waypoint>(newPoints.size());
+        for (final Waypoint waypoint : newPoints) {
+            newPrefixes.put(waypoint.getPrefix(), waypoint);
+        }
+
+        // Copy user modified details of the old waypoints over the new ones
+        for (final Waypoint oldWaypoint : oldPoints) {
+            final String prefix = oldWaypoint.getPrefix();
+            if (newPrefixes.containsKey(prefix)) {
+                newPrefixes.get(prefix).merge(oldWaypoint);
+            } else if (oldWaypoint.isUserDefined() || forceMerge) {
+                newPoints.add(oldWaypoint);
             }
         }
     }
-- 
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