[tz] [tz-announce] 2018f release of tz code and data available

Paul.Koning at dell.com Paul.Koning at dell.com
Mon Oct 22 18:04:13 UTC 2018



> On Oct 22, 2018, at 1:56 PM, Florian Weimer <fweimer at redhat.com> wrote:
> 
> 
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> 
> * Paul Eggert:
> 
>> Stephen Colebourne wrote:
>>> It would be much better for the upstream source to represent the data in a
>>> more standard and backwards compatible way.
>> 
>> The original Japanese regulation does seem to say that the transition
>> occurs Saturday at 25:00 (as this is how such times are often
>> expressed in Japan), and it's better to represent data as close to the
>> original as the format allows. This is not a recent change to the
>> format, which was relaxed to allow 25:00 (and other out-of-range
>> times) in 2007, as first proposed here:
>> 
>> https://mm.icann.org/pipermail/tz/2007-May/014341.html
>> 
>> with no disagreement at the time.
> 
> What's the exact algorithm for normalizing the date?
> Is there only one possible way of doing this?

It seems reasonably obvious and unambiguous, but perhaps it's worth a few lines in the theory file.  Hours are simply offsets from midnight of the stated day, so 25:00 means plus one day plus one hour.  Similarly, days of the month are offsets from the start of the month (one-based), so January 0 is the beginning of the day one day before the start of January.  (That notation appears in the definition of the second, two or three definitions ago.)

	paul



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