    /*
     * call-seq:
     *  native_parse_file(data)
     *
     * Parse the document stored in +data+
     */
    static VALUE native_parse_file(VALUE self, VALUE data)
    {
      xmlSAXHandlerPtr handler;
      Data_Get_Struct(self, xmlSAXHandler, handler);
      xmlSAXUserParseFile(  handler,
                            (void *)self,
                            StringValuePtr(data)
      );
      return data;
    }