diff --git a/common/rdr/InStream.cxx b/common/rdr/InStream.cxx
new file mode 100644
index 0000000..a413b6c
--- /dev/null
+++ b/common/rdr/InStream.cxx
@@ -0,0 +1,35 @@
+/* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
+ * 
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+
+#include <rdr/InStream.h>
+#include <rdr/Exception.h>
+
+using namespace rdr;
+
+U32 InStream::maxStringLength = 65535;
+
+char* InStream::readString()
+{
+  U32 len = readU32();
+  if (len > maxStringLength)
+    throw Exception("InStream max string length exceeded");
+  char* str = new char[len+1];
+  readBytes(str, len);
+  str[len] = 0;
+  return str;
+}