[tz] attic data for the tz database

Paul_Koning at Dell.com Paul_Koning at Dell.com
Thu Aug 29 18:30:07 UTC 2013

On Aug 29, 2013, at 1:51 PM, Paul Eggert <eggert at CS.UCLA.EDU> wrote:

> On 08/29/2013 09:36 AM, Paul_Koning at Dell.com wrote:
>> It's a pretty easy addition to "zic" which I implemented in the
>> version we use internally for the products I work on, exactly for
>> the reason you mention.
> Thanks, is that code something that you and your company would donate
> to the public domain?  If so, it could save us some work.

Quite possibly; I will ask.  We have done open source contributions before, there is a process in place that I can use.
> How does the extension choose which of the alternate pre-1970 (or
> whatever) histories to use?  For example, suppose America/Toronto
> and America/Montreal are the same after 1970, so zic makes them
> links.  Which pre-1970 history does it use, Toronto's or Montreal's?

That's a case I don't have covered; our code only handles cases where you set a horizon later than 1970.  I suppose that the case you mention would have to be handled by recognizing that the data now aren't the same, so it has to generate two real output files instead of one file and one link.  (By the same token, with a later horizon you end up with several files that match when they didn't at the 1970 horizon, in which case more links could be generated as a result.  I didn't bother doing that because our kit building process takes care of such optimizations at a later step.)


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