From 9f43d61c2c4f1a9ae760158d3e57601e39ff4a24 Mon Sep 17 00:00:00 2001
From: Quietust <quietust@gmail.com>
Date: Mon, 13 Feb 2012 09:56:35 -0600
Subject: [PATCH] Fix MapCache crash when in Arena mode

---
 library/include/modules/MapCache.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/library/include/modules/MapCache.h b/library/include/modules/MapCache.h
index 953a7ed00..5c227fa70 100644
--- a/library/include/modules/MapCache.h
+++ b/library/include/modules/MapCache.h
@@ -76,6 +76,11 @@ void SquashRocks ( std::vector< std::vector <uint16_t> > * layerassign, DFHack::
                 materials[xx][yy] = -1;
                 continue;
             }
+            if (mb.biome_indices[test] >= layerassign->size())
+            {
+                materials[xx][yy] = -1;
+                continue;
+            }
             materials[xx][yy] =
             layerassign->at(mb.biome_indices[test])[mb.designation[xx][yy].bits.geolayer_index];
         }