package Time::Local;
-require 5.000;
+use 5.006;
require Exporter;
use Carp;
+use Config;
+use strict;
+use integer;
-@ISA = qw(Exporter);
-@EXPORT = qw(timegm timelocal);
+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);
-# Set up constants
- $SEC = 1;
- $MIN = 60 * $SEC;
- $HR = 60 * $MIN;
- $DAY = 24 * $HR;
# Determine breakpoint for rolling century
- my $thisYear = (localtime())[5];
- $nextCentury = int($thisYear / 100) * 100;
- $breakpoint = ($thisYear + 50) % 100;
- $nextCentury += 100 if $breakpoint < 50;
+my $ThisYear = (localtime())[5];
+my $Breakpoint = ($ThisYear + 50) % 100;
+my $NextCentury = $ThisYear - $ThisYear % 100;
+ $NextCentury += 100 if $Breakpoint < 50;
+my $Century = $NextCentury - 100;
+
+my (%Options, %Cheat);
+
+# 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));
+} else {
+ $Epoc = _daygm(gmtime(0));
+}
+
+%Cheat=(); # clear the cache as epoc has changed
+
+my $MaxInt = ((1<<(8 * $Config{intsize} - 2))-1)*2 + 1;
+my $MaxDay = int(($MaxInt-43200)/86400)-1;
+
+
+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 {
+ $_[0] + 60 * $_[1] + 3600 * $_[2] + 86400 * &_daygm;
+}
+
sub timegm {
- my (@date) = @_;
- if ($date[5] > 999) {
- $date[5] -= 1900;
+ my ($sec,$min,$hour,$mday,$month,$year) = @_;
+
+ if ($year >= 1000) {
+ $year -= 1900;
}
- elsif ($date[5] >= 0 && $date[5] < 100) {
- $date[5] -= 100 if $date[5] > $breakpoint;
- $date[5] += $nextCentury;
+ elsif ($year < 100 and $year >= 0) {
+ $year += ($year > $Breakpoint) ? $Century : $NextCentury;
}
- $ym = pack(C2, @date[5,4]);
- $cheat = $cheat{$ym} || &cheat(@date);
- $cheat
- + $date[0] * $SEC
- + $date[1] * $MIN
- + $date[2] * $HR
- + ($date[3]-1) * $DAY;
-}
-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($tt);
- }
+ unless ($Options{no_range_check}) {
+ if (abs($year) >= 0x7fff) {
+ $year += 1900;
+ croak "Cannot handle date ($sec, $min, $hour, $mday, $month, $year)";
+ }
- my $tzsec = ($gt[1] - $lt[1]) * $MIN + ($gt[2] - $lt[2]) * $HR;
+ croak "Month '$month' out of range 0..11" if $month > 11 or $month < 0;
- my($lday,$gday) = ($lt[7],$gt[7]);
- if($lt[5] > $gt[5]) {
- $tzsec -= $DAY;
- }
- elsif($gt[5] > $lt[5]) {
- $tzsec += $DAY;
+ 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;
}
- else {
- $tzsec += ($gt[7] - $lt[7]) * $DAY;
+
+ 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)";
}
- $tzsec += $HR if($lt[8]);
-
- $time = $t + $tzsec;
- @test = localtime($time + ($tt - $t));
- $time -= $HR if $test[2] != $_[2];
- $time;
+ $sec + 60*$min + 3600*$hour + 86400*$days;
}
-sub cheat {
- $year = $_[5];
- $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);
- $lastguess = "";
- $counter = 0;
- while ($diff = $year - $g[5]) {
- croak "Can't handle date (".join(", ",@_).")" if ++$counter > 255;
- $guess += $diff * (363 * $DAY);
- @g = gmtime($guess);
- if (($thisguess = "@g") eq $lastguess){
- croak "Can't handle date (".join(", ",@_).")";
- #date beyond this machine's integer limit
- }
- $lastguess = $thisguess;
- }
- while ($diff = $month - $g[4]) {
- croak "Can't handle date (".join(", ",@_).")" if ++$counter > 255;
- $guess += $diff * (27 * $DAY);
- @g = gmtime($guess);
- if (($thisguess = "@g") eq $lastguess){
- croak "Can't handle date (".join(", ",@_).")";
- #date beyond this machine's integer limit
- }
- $lastguess = $thisguess;
- }
- @gfake = gmtime($guess-1); #still being sceptic
- if ("@gfake" eq $lastguess){
- croak "Can't handle date (".join(", ",@_).")";
- #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;
+
+sub timegm_nocheck {
+ local $Options{no_range_check} = 1;
+ &timegm;
+}
+
+
+sub timelocal {
+ 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;
=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 fuctions localtime()
+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. While the day of the month is expected to be in
-the range 1..31, the month should be in the range 0..11.
+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,
Years greater than 999 are interpreted as being the actual year,
rather than the offset from 1900. Thus, 1963 would indicate the year
-of Martin Luther King's assassination, not the year 2863.
+Martin Luther King won the Nobel prize, not the year 2863.
=item *
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
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.
+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. The daylight savings offset is currently assumed
-to be one hour.
+also be correct.
=head1 BUGS
The whole scheme for interpreting two-digit years can be considered a bug.
-Note that the cache currently handles only years from 1900 through 2155.
-
The proclivity to croak() is probably a bug.
=cut
+
https://perl5.git.perl.org / perl5.git / blobdiff