Add pre-assert, fix comment
diff --git a/tinyxml2.cpp b/tinyxml2.cpp
index 9928444..ef3b469 100755
--- a/tinyxml2.cpp
+++ b/tinyxml2.cpp
@@ -1846,6 +1846,7 @@
 

 void XMLDocument::SetError( XMLError error, const char* str1, const char* str2 )

 {

+    TIXMLASSERT( error >= 0 && error < XML_ERROR_COUNT );

     _errorID = error;

     _errorStr1 = str1;

     _errorStr2 = str2;

@@ -1853,7 +1854,7 @@
 

 const char* XMLDocument::ErrorName() const

 {

-	TIXMLASSERT(_errorID >= 0 && _errorID < XML_ERROR_COUNT );

+	TIXMLASSERT( _errorID >= 0 && _errorID < XML_ERROR_COUNT );

 	return _errorNames[_errorID];

 }