_asn1_length
_asn1_length (
val[i].length = _asn1_length(t->ptr, elptr);
ret += _asn1_length(t->ptr, el);
datalen = _asn1_length(t->ptr, data);
ret += _asn1_length(t->ptr, element);
ret += _asn1_length(choice->ptr, DPOC(data, choice->offset));