/**
* @param string $matches
* @return string
*/
static function normalizeCharReferencesCallback($matches)
{
$ret = null;
if ($matches[1] != '') {
$ret = Sanitizer::normalizeEntity($matches[1]);
} elseif ($matches[2] != '') {
$ret = Sanitizer::decCharReference($matches[2]);
} elseif ($matches[3] != '') {
$ret = Sanitizer::hexCharReference($matches[3]);
}
if (is_null($ret)) {
return htmlspecialchars($matches[0]);
} else {
return $ret;
}
}