At 15:02 -1000 2000.08.19, Tim Jenness wrote:
>I'm of the camp that feels perl should have a fixed epoch rather than the
>epoch of the underlining OS. Furthermore, I can understand that the OS
>epoch can also be important when looking outside of perl. Thinking this
>over for a while it occurred to me that time() currently has no arguments
>and that an epoch argument would seemingly solve all our problems.
>
>
> time() - returns seconds since Perl epoch
> time("sys") - seconds since start of OS epoch
> time("tai") - seconds since TAI began
> time("jul") - seconds since julian day 0
> time("vms") - seconds since VMS epoch (MJD 0)
> time("wall") - seconds since Larry Wall was born
> etc.
>
>The only assumption here is that time() returns seconds (not necessarily
>integers) from an epoch and that Perl epoch is the thing expected by the
>localtime() replacement. Whether time() returns fractioanl seconds or a
>libtai object (with seconds and nanoseconds) is another issue.
So what would (stat($_))[8,9,10] return? :)
I think maybe what should happen instead is that a function or module be
provided to handle epoch conversions, to and from the default "Perl" epoch.
perl2epoch($perlsec, 'vms'), epoch2perl($vmssec, 'vms').
>All of
>these are simply integer second offsets from each other.
Not quite. For Mac OS, you'd need a third time zone argument (perhaps
offset from GMT), since Mac OS epoch is seconds sin Jan 01, 1904 00:00:00
_local time_: perl2epoch($perlsec, 'macos', '-0500'). Yummy.
Anyway, here is some code that works.
#!perl -wl
my $perlsec = 966770661;
my $epochsec = perl2epoch($perlsec, 'macos', '-0400');
my $perlsec2 = epoch2perl($epochsec, 'macos');
print $perlsec;
print $perlsec2;
print $epochsec;
print scalar localtime $epochsec;
sub perl2epoch {
my($perlsec, $epoch, @extra) = @_;
my $epochsec;
if ($epoch eq 'macos') {
$epochsec = $perlsec + macos_offset();
$epochsec += tz_offset($extra[0]);
}
return $epochsec;
}
sub epoch2perl {
my($epochsec, $epoch, @extra) = @_;
my $perlsec;
if ($epoch eq 'macos') {
$perlsec = $epochsec - macos_offset();
$perlsec -= tz_offset($extra[0]);
}
return $perlsec;
}
sub macos_offset () { 2082844801 }
# guess with Time::Local if not provided?
sub tz_offset {
my($offset) = @_;
my $tz_offset;
if ($offset) {
$tz_offset = $offset * 36;
} else {
require Time::Local;
$tz_offset = sprintf "%+0.4d\n", (Time::Local::timelocal(localtime)
- Time::Local::timelocal(gmtime));
}
return $tz_offset;
}
Returns:
966770661
966770661
3049601062
Sun Aug 20 07:24:22 2000
--
Chris Nandor | [EMAIL PROTECTED] | http://pudge.net/
Andover.Net | [EMAIL PROTECTED] | http://slashcode.com/
