+function common_xml_safe_str($str) {
+ $xmlStr = htmlentities(iconv('UTF-8', 'UTF-8//IGNORE', $str), ENT_NOQUOTES, 'UTF-8');
+
+ // Replace control, formatting, and surrogate characters with '*', ala Twitter
+ return preg_replace('/[\p{Cc}\p{Cf}\p{Cs}]/u', '*', $str);
+}
+