Whatever number of stamps end up in the file, my guess is that the thing
to do is
put at the start of the file a count of the number of bytes worth of
stamp that appear,
then put the stamp information itself at the end of the file. This
minimizes the encroachment
on the twenty remaining bytes of "reserved for future use" space; it
also would allow us to
have longish, easy-for-humans-to-read stamp information (either in
addition to or instead of shorter,
easy-for-computers-to-process information).
My sense is that one stamp might be sufficient.
A client picking up time zone information from multiple sources would
use the one with the largest stamp.
The stamp might be automatically generated as a function of
the maximum "until" time appearing on a "Zone" line for the zone
in question
and
the maximum "from" and "to" years appearing on a "Rule" line for
the zone in question.
Doing this would eliminate the need for separate maintenance of
information from which to generate
stamps; it would also avoid adding information to the zic input files
that old versions of zic
would not be able to handle. The down side would be that if we learned
of a correction to zone information
that only affected past times, we wouldn't get an *automatic* update of
the stamp for the zone.
Comments?
--ado
