+
+ /**
+ * check file exists and is readable
+ *
+ * returns true, if everything is ok, otherwise false
+ * if $silent is not set, this function will output and
+ * error message
+ */
+ private function check_readable($file, $silent = null)
+ {
+ if(!file_exists($file)) {
+ if(!isset($silent))
+ print "File \"". $file ."\" does not exist.\n";
+ return false;
+ }
+
+ if(!is_readable($file)) {
+ if(!isset($silent))
+ print "File \"". $file ."\" is not reachable for user ". $this->getuid() ."\n";
+ return false;
+ }
+
+ return true;
+
+ } // check_readable()