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@uk.ibm.com
tel:+44-1962-815848




From:        Mike Beckerle <mbeckerle.dfdl@gmail.com>
To:        "dfdl-wg@ogf.org" <dfdl-wg@ogf.org>,
Date:        09/09/2013 15:59
Subject:        [DFDL-WG] ambiguity - mandatory alignment for text (12.1.2)
Sent by:        dfdl-wg-bounces@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
Please note: Contributions to the DFDL Workgroup's email discussions are subject to the OGF Intellectual Property Policy
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