function encodeDER($source, $mapping, $special = array())
    {
        $this->location = array();
        return $this->_encode_der($source, $mapping, null, $special);
    }
function encodeDER($source, $mapping, $special = array())
    {
        $this->location = array();
        return $this->_encode_der($source, $mapping, null, $special);
    }
function encodeDER ( $ source , $ mapping , $ special = array ( ) ) { $ this -> location = array ( ) ; return $ this -> _encode_der ( $ source , $ mapping , null , $ special ) ; }
ASN.1 Encode

DER-encodes an ASN.1 semantic mapping ($mapping).  Some libraries would probably call this function
an ASN.1 compiler.

"Special" mappings can be applied via $special.

@param string $source
@param string $mapping
@param int $idx
@return string
@access public
ASN . 1 Encode