[DFDL-WG] ICU and rounding for fractional seconds

[Steve Hanson]

Mike

I suspect that the statement about rounding of fractional seconds was 
introduced before the ICU behaviour was realised. We should go along with 
the ICU behaviour for ease of implementation.  I'll raise at the next DFDL 
WG call, and get a clarification from ICU in the meantime.

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, 
Date:   12/04/2013 15:54
Subject:        [DFDL-WG] ICU and rounding for fractional seconds
Sent by:        dfdl-wg-bounces at ogf.org




Steve Lawrence on the Daffodil team has been implementing the date & time 
features. He has identified this issue:
ICU doesn't support rounding, in fact they explicitly state rounding is 
not performed. From the javadoc:
FieldPosition selector for 'S' field alignment, corresponding to the 
Calendar.MILLISECOND field. Note: Time formats that use 'S' can display a 
maximum of three significant digits for fractional seconds, corresponding 
to millisecond resolution and a fractional seconds sub-pattern of SSS. If 
the sub-pattern is S or SS, the fractional seconds value will be truncated 
(not rounded) to the number of display places specified. If the fractional 
seconds sub-pattern is longer than SSS, the additional display places will 
be filled with zeros.
Are we reading the DFDL spec right? In regards to fractional seconds, it 
says:
Round up rounding must occur when converting between external and internal
representations.
Does this mean that a time of 01:02:03.0019 should be represented as 
01:02:03.002 in the infoset rather than 01:02:03.001? I don't think ICU 
supports that, and I thought DFDL attempted to fit as closely with ICU as 
possible, so this seems an odd change from ICU.
--
  dfdl-wg mailing list
  dfdl-wg at ogf.org
  https://www.ogf.org/mailman/listinfo/dfdl-wg

Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 
741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.ogf.org/pipermail/dfdl-wg/attachments/20130415/8cc9d059/attachment-0001.html>