package Time::Local;
-require 5.000;
+
require Exporter;
use Carp;
+use Config;
+use strict;
+use integer;
+
+use vars qw( $VERSION @ISA @EXPORT @EXPORT_OK );
+$VERSION = '1.07';
+@ISA = qw( Exporter );
+@EXPORT = qw( timegm timelocal );
+@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;
+
+ # for a negative offset from GMT, and if the original date
+ # was a non-extent gap in a forward DST jump, we should
+ # now have the wrong answer - undo the DST adjust;
+
+ return $loc_t if $zone_off <= 0;
-@ISA = qw(Exporter);
-@EXPORT = qw(timegm timelocal);
+ my ($s,$m,$h) = localtime($loc_t);
+ $loc_t -= $dst_off if $s != $_[0] || $m != $_[1] || $h != $_[2];
+
+ $loc_t;
+}
+
+
+sub timelocal_nocheck {
+ local $Options{no_range_check} = 1;
+ &timelocal;
+}
+
+1;
+
+__END__
=head1 NAME
=head1 SYNOPSIS
- $time = timelocal($sec,$min,$hours,$mday,$mon,$year);
- $time = timegm($sec,$min,$hours,$mday,$mon,$year);
+ $time = timelocal($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 system epoch
+(Midnight, January 1, 1970 UTC on Unix, for example). This value can
+be positive or negative, though POSIX only requires support for
+positive values, so dates before the system's epoch may not work on
+all operating systems.
+
+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
-themselves are guessed by successive approximation starting at the
-current time, since most dates seen in practice are close to the
-current date. Unlike algorithms that do a binary search (calling gmtime
-once for each bit of the time value, resulting in 32 calls), this algorithm
-calls it at most 6 times, and usually only once or twice. If you hit
-the month cache, of course, it doesn't call it at all.
-
-timelocal is implemented using the same cache. We just assume that we're
+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. The timezone is determined by examining
-the result of localtime(0) when the package is initialized. The daylight
-savings offset is currently assumed to be one hour.
+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.
-Both routines return -1 if the integer limit is hit. I.e. for dates
-after the 1st of January, 2038 on most machines.
+=head1 BUGS
-=cut
+The whole scheme for interpreting two-digit years can be considered a bug.
-BEGIN {
- $SEC = 1;
- $MIN = 60 * $SEC;
- $HR = 60 * $MIN;
- $DAY = 24 * $HR;
- $epoch = (localtime(2*$DAY))[5]; # Allow for bugs near localtime == 0.
+The proclivity to croak() is probably a bug.
- $YearFix = ((gmtime(946684800))[5] == 100) ? 100 : 0;
+=head1 SUPPORT
-}
+Support for this module is provided via the perl5-porters@perl.org
+email list. See http://lists.perl.org/ for more details.
-sub timegm {
- $ym = pack(C2, @_[5,4]);
- $cheat = $cheat{$ym} || &cheat;
- return -1 if $cheat<0 and $^O ne 'VMS';
- $cheat + $_[0] * $SEC + $_[1] * $MIN + $_[2] * $HR + ($_[3]-1) * $DAY;
-}
+Please submit bugs using the RT system at bugs.perl.org, the perlbug
+script, or as a last resort, to the perl5-porters@perl.org list.
-sub timelocal {
- my $t = &timegm;
- my $tt = $t;
-
- my (@lt) = localtime($t);
- my (@gt) = gmtime($t);
- if ($t < $DAY and ($lt[5] >= 70 or $gt[5] >= 70 )) {
- # Wrap error, too early a date
- # Try a safer date
- $tt = $DAY;
- @lt = localtime($tt);
- @gt = gmtime($tt);
- }
+=head1 AUTHOR
- my $tzsec = ($gt[1] - $lt[1]) * $MIN + ($gt[2] - $lt[2]) * $HR;
+This module is based on a Perl 4 library, timelocal.pl, that was
+included with Perl 4.036, and was most likely written by Tom
+Christiansen.
- my($lday,$gday) = ($lt[7],$gt[7]);
- if($lt[5] > $gt[5]) {
- $tzsec -= $DAY;
- }
- elsif($gt[5] > $lt[5]) {
- $tzsec += $DAY;
- }
- else {
- $tzsec += ($gt[7] - $lt[7]) * $DAY;
- }
+The current version was written by Graham Barr.
- $tzsec += $HR if($lt[8]);
-
- $time = $t + $tzsec;
- return -1 if $cheat<0 and $^O ne 'VMS';
- @test = localtime($time + ($tt - $t));
- $time -= $HR if $test[2] != $_[2];
- $time;
-}
+It is now being maintained separately from the Perl core by Dave
+Rolsky, <autarch@urth.org>.
-sub cheat {
- $year = $_[5];
- $year -= 1900
- if $year > 1900;
- $month = $_[4];
- croak "Month '$month' out of range 0..11" if $month > 11 || $month < 0;
- croak "Day '$_[3]' out of range 1..31" if $_[3] > 31 || $_[3] < 1;
- croak "Hour '$_[2]' out of range 0..23" if $_[2] > 23 || $_[2] < 0;
- croak "Minute '$_[1]' out of range 0..59" if $_[1] > 59 || $_[1] < 0;
- croak "Second '$_[0]' out of range 0..59" if $_[0] > 59 || $_[0] < 0;
- $guess = $^T;
- @g = gmtime($guess);
- $year += $YearFix if $year < $epoch;
- $lastguess = "";
- $counter = 0;
- while ($diff = $year - $g[5]) {
- croak "Couldn't handle date (".join(", ",@_).")" if ++$counter > 255;
- $guess += $diff * (363 * $DAY);
- @g = gmtime($guess);
- if (($thisguess = "@g") eq $lastguess){
- return -1; #date beyond this machine's integer limit
- }
- $lastguess = $thisguess;
- }
- while ($diff = $month - $g[4]) {
- croak "Couldn't handle date (".join(", ",@_).")" if ++$counter > 255;
- $guess += $diff * (27 * $DAY);
- @g = gmtime($guess);
- if (($thisguess = "@g") eq $lastguess){
- return -1; #date beyond this machine's integer limit
- }
- $lastguess = $thisguess;
- }
- @gfake = gmtime($guess-1); #still being sceptic
- if ("@gfake" eq $lastguess){
- return -1; #date beyond this machine's integer limit
- }
- $g[3]--;
- $guess -= $g[0] * $SEC + $g[1] * $MIN + $g[2] * $HR + $g[3] * $DAY;
- $cheat{$ym} = $guess;
-}
+=cut
-1;
projects / p5sagit/p5-mst-13.2.git / blobdiff