Noted when I reviewed latest spec - endOfParent and unparsing is not fully thought through.

The spec today says that I can use endOfParent with binary data. There is a restriction in section 12.3.8, but it only applies when an element is endOfParent and its parent is lengthKind delimited.

There are a couple of cases to consider:

1) Binary data of restricted length (see list in other email "proposed clarification/narrowing - delimited binary data should decimal"). I don't think it makes sense to allow these. We don't allow these binary reps for delimited.

2) Text data of variable length when unparsing. Box scenario. If the data in the infoset is shorter than the space in the box, what we do?  I think we should pad to box length with appropriate padChar, according to justification, as that is effectively a 'specified length'. Error if textPadKind is 'none'. Use parent's lengthUnits.

3) HexBinary data of variable length when unparsing. Box scenario. If the data in the infoset is shorter than the space in the box, what we do?  I think we should right-pad to box length with fill byte, as that is effectively a 'specified length'.

4) Packed/BCD binary data of variable length when unparsing. Box scenario. If the data in the infoset is shorter than the space in the box, what we do?  I think we should pad to box length with zero bytes, according to justification, as that is effectively a 'specified length'.  (Must be zero bytes and not fill byte as must be numeric in order to be parsed).

In relation to 2 - 4, note that lengthKind 'endOfParent' can only be used with a parent lengthKind of 'explicit', 'pattern', 'prefixed' or 'endOfParent' or a choice with choiceLengthKind 'explicit', so the box scenario when unparsing therefore occurs only when lengthKind is 'explicit' or choiceLengthKind is 'explicit' - these are the cases when the length is known.  Also note that when there are nested 'endOfParent' elements (which is allowed) then all padding must be done on the simple element (ie, the innermost element), to ensure that what is output can be parsed.

Regards

Steve Hanson
Architect, Data Format Description Language (DFDL)
Co-Chair, OGF DFDL Working Group
IBM SWG, Hursley, UK
smh@uk.ibm.com
tel:+44-1962-815848