Check track iterators for validity before using

diff --git a/source/libr2c2/train.cpp b/source/libr2c2/train.cpp
index b2b4899f9aa6eb7cc1ad83cee23039d073c4b5f4..5b03e9b5e6946827a966080de5fb86084a8db0fa 100644 (file)
--- a/source/libr2c2/train.cpp
+++ b/source/libr2c2/train.cpp
@@ -1294,7 +1294,7 @@ bool Train::is_valid_diversion(const Route &diversion, const TrackIter &from)
 
                track1 = track1.next(path);
 
-               if(track1.looped())
+               if(!track1 || track1.looped())
                        return false;
        }
 
@@ -1312,6 +1312,8 @@ bool Train::is_valid_diversion(const Route &diversion, const TrackIter &from)
                bool ok = (track2!=from && diversion.has_track(*track2));
 
                track2 = track2.next(path);
+               if(!track2)
+                       return false;
 
                if(ok)
                        break;