summaryrefslogtreecommitdiff
path: root/Master/xemtex/perl/lib/Time/Local.pm
diff options
context:
space:
mode:
Diffstat (limited to 'Master/xemtex/perl/lib/Time/Local.pm')
-rw-r--r--Master/xemtex/perl/lib/Time/Local.pm255
1 files changed, 255 insertions, 0 deletions
diff --git a/Master/xemtex/perl/lib/Time/Local.pm b/Master/xemtex/perl/lib/Time/Local.pm
new file mode 100644
index 00000000000..faef1d78694
--- /dev/null
+++ b/Master/xemtex/perl/lib/Time/Local.pm
@@ -0,0 +1,255 @@
+package Time::Local;
+use 5.006;
+require Exporter;
+use Carp;
+use Config;
+use strict;
+use integer;
+
+our $VERSION = '1.04';
+our @ISA = qw( Exporter );
+our @EXPORT = qw( timegm timelocal );
+our @EXPORT_OK = qw( timegm_nocheck timelocal_nocheck );
+
+my @MonthDays = (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
+
+# Determine breakpoint for rolling century
+my $ThisYear = (localtime())[5];
+my $Breakpoint = ($ThisYear + 50) % 100;
+my $NextCentury = $ThisYear - $ThisYear % 100;
+ $NextCentury += 100 if $Breakpoint < 50;
+my $Century = $NextCentury - 100;
+my $SecOff = 0;
+
+my (%Options, %Cheat);
+
+my $MaxInt = ((1<<(8 * $Config{intsize} - 2))-1)*2 + 1;
+my $MaxDay = int(($MaxInt-43200)/86400)-1;
+
+# Determine the EPOC day for this machine
+my $Epoc = 0;
+if ($^O eq 'vos') {
+# work around posix-977 -- VOS doesn't handle dates in
+# the range 1970-1980.
+ $Epoc = _daygm((0, 0, 0, 1, 0, 70, 4, 0));
+}
+elsif ($^O eq 'MacOS') {
+ no integer;
+
+ $MaxDay *=2 if $^O eq 'MacOS'; # time_t unsigned ... quick hack?
+ # MacOS time() is seconds since 1 Jan 1904, localtime
+ # so we need to calculate an offset to apply later
+ $Epoc = 693901;
+ $SecOff = timelocal(localtime(0)) - timelocal(gmtime(0));
+ $Epoc += _daygm(gmtime(0));
+}
+else {
+ $Epoc = _daygm(gmtime(0));
+}
+
+%Cheat=(); # clear the cache as epoc has changed
+
+sub _daygm {
+ $_[3] + ($Cheat{pack("ss",@_[4,5])} ||= do {
+ my $month = ($_[4] + 10) % 12;
+ my $year = $_[5] + 1900 - $month/10;
+ 365*$year + $year/4 - $year/100 + $year/400 + ($month*306 + 5)/10 - $Epoc
+ });
+}
+
+
+sub _timegm {
+ my $sec = $SecOff + $_[0] + 60 * $_[1] + 3600 * $_[2];
+
+ no integer;
+
+ $sec + 86400 * &_daygm;
+}
+
+
+sub timegm {
+ my ($sec,$min,$hour,$mday,$month,$year) = @_;
+
+ if ($year >= 1000) {
+ $year -= 1900;
+ }
+ elsif ($year < 100 and $year >= 0) {
+ $year += ($year > $Breakpoint) ? $Century : $NextCentury;
+ }
+
+ unless ($Options{no_range_check}) {
+ if (abs($year) >= 0x7fff) {
+ $year += 1900;
+ croak "Cannot handle date ($sec, $min, $hour, $mday, $month, $year)";
+ }
+
+ croak "Month '$month' out of range 0..11" if $month > 11 or $month < 0;
+
+ my $md = $MonthDays[$month];
+ ++$md unless $month != 1 or $year % 4 or !($year % 400);
+
+ croak "Day '$mday' out of range 1..$md" if $mday > $md or $mday < 1;
+ croak "Hour '$hour' out of range 0..23" if $hour > 23 or $hour < 0;
+ croak "Minute '$min' out of range 0..59" if $min > 59 or $min < 0;
+ croak "Second '$sec' out of range 0..59" if $sec > 59 or $sec < 0;
+ }
+
+ my $days = _daygm(undef, undef, undef, $mday, $month, $year);
+
+ unless ($Options{no_range_check} or abs($days) < $MaxDay) {
+ $year += 1900;
+ croak "Cannot handle date ($sec, $min, $hour, $mday, $month, $year)";
+ }
+
+ $sec += $SecOff + 60*$min + 3600*$hour;
+
+ no integer;
+
+ $sec + 86400*$days;
+}
+
+
+sub timegm_nocheck {
+ local $Options{no_range_check} = 1;
+ &timegm;
+}
+
+
+sub timelocal {
+ no integer;
+ my $ref_t = &timegm;
+ my $loc_t = _timegm(localtime($ref_t));
+
+ # Is there a timezone offset from GMT or are we done
+ my $zone_off = $ref_t - $loc_t
+ or return $loc_t;
+
+ # Adjust for timezone
+ $loc_t = $ref_t + $zone_off;
+
+ # Are we close to a DST change or are we done
+ my $dst_off = $ref_t - _timegm(localtime($loc_t))
+ or return $loc_t;
+
+ # Adjust for DST change
+ $loc_t + $dst_off;
+}
+
+
+sub timelocal_nocheck {
+ local $Options{no_range_check} = 1;
+ &timelocal;
+}
+
+1;
+
+__END__
+
+=head1 NAME
+
+Time::Local - efficiently compute time from local and GMT time
+
+=head1 SYNOPSIS
+
+ $time = timelocal($sec,$min,$hour,$mday,$mon,$year);
+ $time = timegm($sec,$min,$hour,$mday,$mon,$year);
+
+=head1 DESCRIPTION
+
+These routines are the inverse of built-in perl functions localtime()
+and gmtime(). They accept a date as a six-element array, and return
+the corresponding time(2) value in seconds since the Epoch (Midnight,
+January 1, 1970). This value can be positive or negative.
+
+It is worth drawing particular attention to the expected ranges for
+the values provided. The value for the day of the month is the actual day
+(ie 1..31), while the month is the number of months since January (0..11).
+This is consistent with the values returned from localtime() and gmtime().
+
+The timelocal() and timegm() functions perform range checking on the
+input $sec, $min, $hour, $mday, and $mon values by default. If you'd
+rather they didn't, you can explicitly import the timelocal_nocheck()
+and timegm_nocheck() functions.
+
+ use Time::Local 'timelocal_nocheck';
+
+ {
+ # The 365th day of 1999
+ print scalar localtime timelocal_nocheck 0,0,0,365,0,99;
+
+ # The twenty thousandth day since 1970
+ print scalar localtime timelocal_nocheck 0,0,0,20000,0,70;
+
+ # And even the 10,000,000th second since 1999!
+ print scalar localtime timelocal_nocheck 10000000,0,0,1,0,99;
+ }
+
+Your mileage may vary when trying these with minutes and hours,
+and it doesn't work at all for months.
+
+Strictly speaking, the year should also be specified in a form consistent
+with localtime(), i.e. the offset from 1900.
+In order to make the interpretation of the year easier for humans,
+however, who are more accustomed to seeing years as two-digit or four-digit
+values, the following conventions are followed:
+
+=over 4
+
+=item *
+
+Years greater than 999 are interpreted as being the actual year,
+rather than the offset from 1900. Thus, 1963 would indicate the year
+Martin Luther King won the Nobel prize, not the year 2863.
+
+=item *
+
+Years in the range 100..999 are interpreted as offset from 1900,
+so that 112 indicates 2012. This rule also applies to years less than zero
+(but see note below regarding date range).
+
+=item *
+
+Years in the range 0..99 are interpreted as shorthand for years in the
+rolling "current century," defined as 50 years on either side of the current
+year. Thus, today, in 1999, 0 would refer to 2000, and 45 to 2045,
+but 55 would refer to 1955. Twenty years from now, 55 would instead refer
+to 2055. This is messy, but matches the way people currently think about
+two digit dates. Whenever possible, use an absolute four digit year instead.
+
+=back
+
+The scheme above allows interpretation of a wide range of dates, particularly
+if 4-digit years are used.
+
+Please note, however, that the range of dates that can be actually be handled
+depends on the size of an integer (time_t) on a given platform.
+Currently, this is 32 bits for most systems, yielding an approximate range
+from Dec 1901 to Jan 2038.
+
+Both timelocal() and timegm() croak if given dates outside the supported
+range.
+
+=head1 IMPLEMENTATION
+
+These routines are quite efficient and yet are always guaranteed to agree
+with localtime() and gmtime(). We manage this by caching the start times
+of any months we've seen before. If we know the start time of the month,
+we can always calculate any time within the month. The start times
+are calculated using a mathematical formula. Unlike other algorithms
+that do multiple calls to gmtime().
+
+timelocal() is implemented using the same cache. We just assume that we're
+translating a GMT time, and then fudge it when we're done for the timezone
+and daylight savings arguments. Note that the timezone is evaluated for
+each date because countries occasionally change their official timezones.
+Assuming that localtime() corrects for these changes, this routine will
+also be correct.
+
+=head1 BUGS
+
+The whole scheme for interpreting two-digit years can be considered a bug.
+
+The proclivity to croak() is probably a bug.
+
+=cut
+