if ( $str != '' && preg_match( "!<\?xml\b(.*?)\?>!si", $str, $matches ) ) {
if ( preg_match( $encodingRegex, $matches[1], $encMatch )
&& !in_array( strtoupper( $encMatch[1] ), self::$safeXmlEncodings )
if ( $str != '' && preg_match( "!<\?xml\b(.*?)\?>!si", $str, $matches ) ) {
if ( preg_match( $encodingRegex, $matches[1], $encMatch )
&& !in_array( strtoupper( $encMatch[1] ), self::$safeXmlEncodings )