Assert for impossible case
diff --git a/tinyxml2.cpp b/tinyxml2.cpp
index ef00f13..5b32f40 100755
--- a/tinyxml2.cpp
+++ b/tinyxml2.cpp
@@ -338,8 +338,9 @@
         case 1:

             --output;

             *output = (char)(input | FIRST_BYTE_MARK[*length]);

-        default:

             break;

+        default:

+            TIXMLASSERT( false );

     }

 }