[DFDL-WG] ambiguity - mandatory alignment for text (12.1.2)

[Steve Hanson]

Agreed on WG call that there was no contradiction - the first is a rule 
about specifying alignment, the second is about skipping to an alignment.

Regards

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



From:   Mike Beckerle <mbeckerle.dfdl at gmail.com>
To:     "dfdl-wg at ogf.org" <dfdl-wg at ogf.org>, 
Date:   09/09/2013 15:59
Subject:        [DFDL-WG] ambiguity - mandatory alignment for text 
(12.1.2)
Sent by:        dfdl-wg-bounces at ogf.org



These two paragraphs contradict each other.

When processing textual data, it is a schema definition error if the 
dfdl:alignment and dfdl:alignmentUnits properties are used to specify 
alignment that is not a multiple of the encoding-specified mandatory 
alignment.
If the data is not aligned to the proper boundary for the encoding when 
textual data is processed, then bits are skipped (parsing) or filled from 
dfdl:fillByte (unparsing) to achieve the mandatory alignment.

So is it to be SDE (conservative), or just move over to the mandatory 
alignment? E.g.,

<xs:sequence dfdl:encoding="utf-8" dfdl:alignment="7" 
dfdl:alignmentUnits="bits" dfdl:initiator="hello">....

The alignment property says 7 bits, but the initiator is utf-8 which 
requires 8 bits. So we either SDE, or we just add additional alignment 
bits to align the initiator text.


Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology | 
www.tresys.com
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