tighten up the error checks
diff --git a/tinyxml2.cpp b/tinyxml2.cpp
index 81296e6..cefd22d 100755
--- a/tinyxml2.cpp
+++ b/tinyxml2.cpp
@@ -1857,7 +1857,7 @@
         return _errorID;

     }

 

-    if ( filelength >= (size_t)-1 ) {

+    if ( (size_t)filelength >= (size_t)-1 ) {

         // Cannot handle files which won't fit in buffer together with null terminator

         SetError( XML_ERROR_FILE_READ_ERROR, 0, 0 );

         return _errorID;