PHP Convert String to HTML Entity Reference_PHP Tutorial

class HtmlEncode { 
    static $_convertToHtmlEntitiesSrcEncoding='UTF-8'; 
 
    /**
* Convert non-ASCII string to HTML entity
*
* @example HtmlEncode::encode("I believe it"); //Output:我信了
* @param string $s The string to be encoded
* @return string Returns the HTML entity reference www.2cto.com
​​*/ 
    public static function encode($s,$srcEncoding='UTF-8') { 
        self::$_convertToHtmlEntitiesSrcEncoding=$srcEncoding; 
        return preg_replace_callback('|[^x00-x7F]+|',array(__CLASS__,'_convertToHtmlEntities'),$s); 
    } 
 
    public static function _convertToHtmlEntities($data) { 
        if (is_array($data)) { 
            $chars=str_split(iconv(self::$_convertToHtmlEntitiesSrcEncoding,"UCS-2BE",$data[0]),2); 
            $chars=array_map(array(__CLASS__,__FUNCTION__),$chars); 
            return join("",$chars); 
        } else { 
            $code=hexdec(sprintf("%02s%02s;",dechex(ord($data {0})),dechex(ord($data {1})))); 
            return sprintf("%s;",$code); 
        } 
    } 
 
}