des_cblock		T_BYTES
des_key_schedule	T_BYTES
struct des_ks_struct *	T_DES_SCHED_PTR
des_cblock *		T_BYTES_PTR

INPUT
T_BYTES_PTR
	if (SvOK($arg) && SvCUR($arg) == sizeof(*$var))
	    $var = ($type) SvPV($arg, na);
	else
	    croak(\"$var must be exactly %lu bytes long\", (unsigned long) sizeof(*$var))

T_DES_SCHED_PTR
	if (SvOK($arg) && SvCUR($arg) == sizeof(des_key_schedule))
	    $var = ($type) SvPV($arg, na);
	else
	    croak(\"$var must be exactly %lu bytes long\",
		  (unsigned long) sizeof(des_key_schedule))

OUTPUT
T_BYTES
	sv_setpvn($arg, (char *) $var, sizeof($var));

T_BYTES_PTR
	UNIMPLEMENTED

T_DES_SCHED_PTR
	UNIMPLEMENTED
