The DateTime module allows handling of a large range of dates, much
larger than the standard unix epoch (from ~1901 to ~2038). This is
really nice. But when calling the DateTime->from_epoch(epoch => 2**31)
gives not 2038 as I hoped for, but 1901 due to an internal call to gmtime.
Since I'm working with predictions (of air pollution) up to year 2050 or
even 2100, and several models save dates in epoch longlong seconds, I
have to translate those large epoch seconds.
Some 64bit OSes start implementing a gmtime64 routine, but this is not
(yet?) available in perl. As workaround, I use:
use constant SECSPERDAY => 24*60*60;
my $dateTime;
if (($epoch > (2**31 - 1)) || ($epoch < (-1 *(2**31)))) {
my $days = int($epoch / SECSPERDAY);
my $secs = $epoch - ($days*SECSPERDAY);
$dateTime = DateTime->from_epoch(epoch => $secs)->add(days => $days);
} else {
$dateTime = DateTime->from_epoch(epoch => $epoch);
}
print $dateTime, "\n";
Wouldn't it be possible to implement this directly into the from_epoch
routine. Caveats would be missing leap-seconds before 1901 and after
2038. (Any more?) But at least dates up to year 5million would be possible.
Best regards,
Heiko
