| 1 |
package Time::Local; |
| 2 |
|
| 3 |
require Exporter; |
| 4 |
use Carp; |
| 5 |
use Config; |
| 6 |
use strict; |
| 7 |
use integer; |
| 8 |
|
| 9 |
use vars qw( $VERSION @ISA @EXPORT @EXPORT_OK ); |
| 10 |
$VERSION = '1.11'; |
| 11 |
$VERSION = eval $VERSION; |
| 12 |
@ISA = qw( Exporter ); |
| 13 |
@EXPORT = qw( timegm timelocal ); |
| 14 |
@EXPORT_OK = qw( timegm_nocheck timelocal_nocheck ); |
| 15 |
|
| 16 |
my @MonthDays = (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31); |
| 17 |
|
| 18 |
# Determine breakpoint for rolling century |
| 19 |
my $ThisYear = (localtime())[5]; |
| 20 |
my $Breakpoint = ($ThisYear + 50) % 100; |
| 21 |
my $NextCentury = $ThisYear - $ThisYear % 100; |
| 22 |
$NextCentury += 100 if $Breakpoint < 50; |
| 23 |
my $Century = $NextCentury - 100; |
| 24 |
my $SecOff = 0; |
| 25 |
|
| 26 |
my (%Options, %Cheat, %Min, %Max); |
| 27 |
my ($MinInt, $MaxInt); |
| 28 |
|
| 29 |
if ($^O eq 'MacOS') { |
| 30 |
# time_t is unsigned... |
| 31 |
$MaxInt = (1 << (8 * $Config{intsize})) - 1; |
| 32 |
$MinInt = 0; |
| 33 |
} else { |
| 34 |
$MaxInt = ((1 << (8 * $Config{intsize} - 2))-1)*2 + 1; |
| 35 |
$MinInt = -$MaxInt - 1; |
| 36 |
|
| 37 |
# On Win32 (and others?) time_t appears to be signed, but negative |
| 38 |
# epochs still don't work. - XXX - this is experimental |
| 39 |
$MinInt = 0 |
| 40 |
unless defined ((localtime(-1))[0]); |
| 41 |
} |
| 42 |
|
| 43 |
$Max{Day} = ($MaxInt >> 1) / 43200; |
| 44 |
$Min{Day} = $MinInt ? -($Max{Day} + 1) : 0; |
| 45 |
|
| 46 |
$Max{Sec} = $MaxInt - 86400 * $Max{Day}; |
| 47 |
$Min{Sec} = $MinInt - 86400 * $Min{Day}; |
| 48 |
|
| 49 |
# Determine the EPOC day for this machine |
| 50 |
my $Epoc = 0; |
| 51 |
if ($^O eq 'vos') { |
| 52 |
# work around posix-977 -- VOS doesn't handle dates in |
| 53 |
# the range 1970-1980. |
| 54 |
$Epoc = _daygm((0, 0, 0, 1, 0, 70, 4, 0)); |
| 55 |
} |
| 56 |
elsif ($^O eq 'MacOS') { |
| 57 |
no integer; |
| 58 |
|
| 59 |
# MacOS time() is seconds since 1 Jan 1904, localtime |
| 60 |
# so we need to calculate an offset to apply later |
| 61 |
$Epoc = 693901; |
| 62 |
$SecOff = timelocal(localtime(0)) - timelocal(gmtime(0)); |
| 63 |
$Epoc += _daygm(gmtime(0)); |
| 64 |
} |
| 65 |
else { |
| 66 |
$Epoc = _daygm(gmtime(0)); |
| 67 |
} |
| 68 |
|
| 69 |
%Cheat=(); # clear the cache as epoc has changed |
| 70 |
|
| 71 |
sub _daygm { |
| 72 |
$_[3] + ($Cheat{pack("ss",@_[4,5])} ||= do { |
| 73 |
my $month = ($_[4] + 10) % 12; |
| 74 |
my $year = $_[5] + 1900 - $month/10; |
| 75 |
365*$year + $year/4 - $year/100 + $year/400 + ($month*306 + 5)/10 - $Epoc |
| 76 |
}); |
| 77 |
} |
| 78 |
|
| 79 |
|
| 80 |
sub _timegm { |
| 81 |
my $sec = $SecOff + $_[0] + 60 * $_[1] + 3600 * $_[2]; |
| 82 |
|
| 83 |
no integer; |
| 84 |
|
| 85 |
$sec + 86400 * &_daygm; |
| 86 |
} |
| 87 |
|
| 88 |
|
| 89 |
sub _zoneadjust { |
| 90 |
my ($day, $sec, $time) = @_; |
| 91 |
|
| 92 |
$sec = $sec + _timegm(localtime($time)) - $time; |
| 93 |
if ($sec >= 86400) { $day++; $sec -= 86400; } |
| 94 |
if ($sec < 0) { $day--; $sec += 86400; } |
| 95 |
|
| 96 |
($day, $sec); |
| 97 |
} |
| 98 |
|
| 99 |
|
| 100 |
sub timegm { |
| 101 |
my ($sec,$min,$hour,$mday,$month,$year) = @_; |
| 102 |
|
| 103 |
if ($year >= 1000) { |
| 104 |
$year -= 1900; |
| 105 |
} |
| 106 |
elsif ($year < 100 and $year >= 0) { |
| 107 |
$year += ($year > $Breakpoint) ? $Century : $NextCentury; |
| 108 |
} |
| 109 |
|
| 110 |
unless ($Options{no_range_check}) { |
| 111 |
if (abs($year) >= 0x7fff) { |
| 112 |
$year += 1900; |
| 113 |
croak "Cannot handle date ($sec, $min, $hour, $mday, $month, *$year*)"; |
| 114 |
} |
| 115 |
|
| 116 |
croak "Month '$month' out of range 0..11" if $month > 11 or $month < 0; |
| 117 |
|
| 118 |
my $md = $MonthDays[$month]; |
| 119 |
# ++$md if $month == 1 and $year % 4 == 0 and |
| 120 |
# ($year % 100 != 0 or ($year + 1900) % 400 == 0); |
| 121 |
++$md unless $month != 1 or $year % 4 or !($year % 400); |
| 122 |
|
| 123 |
croak "Day '$mday' out of range 1..$md" if $mday > $md or $mday < 1; |
| 124 |
croak "Hour '$hour' out of range 0..23" if $hour > 23 or $hour < 0; |
| 125 |
croak "Minute '$min' out of range 0..59" if $min > 59 or $min < 0; |
| 126 |
croak "Second '$sec' out of range 0..59" if $sec > 59 or $sec < 0; |
| 127 |
} |
| 128 |
|
| 129 |
my $days = _daygm(undef, undef, undef, $mday, $month, $year); |
| 130 |
my $xsec = $sec + $SecOff + 60*$min + 3600*$hour; |
| 131 |
|
| 132 |
unless ($Options{no_range_check} |
| 133 |
or ($days > $Min{Day} or $days == $Min{Day} and $xsec >= $Min{Sec}) |
| 134 |
and ($days < $Max{Day} or $days == $Max{Day} and $xsec <= $Max{Sec})) |
| 135 |
{ |
| 136 |
warn "Day too small - $days > $Min{Day}\n" if $days < $Min{Day}; |
| 137 |
warn "Day too big - $days > $Max{Day}\n" if $days > $Max{Day}; |
| 138 |
warn "Sec too small - $days < $Min{Sec}\n" if $days < $Min{Sec}; |
| 139 |
warn "Sec too big - $days > $Max{Sec}\n" if $days > $Max{Sec}; |
| 140 |
$year += 1900; |
| 141 |
croak "Cannot handle date ($sec, $min, $hour, $mday, $month, $year)"; |
| 142 |
} |
| 143 |
|
| 144 |
no integer; |
| 145 |
|
| 146 |
$xsec + 86400 * $days; |
| 147 |
} |
| 148 |
|
| 149 |
|
| 150 |
sub timegm_nocheck { |
| 151 |
local $Options{no_range_check} = 1; |
| 152 |
&timegm; |
| 153 |
} |
| 154 |
|
| 155 |
|
| 156 |
sub timelocal { |
| 157 |
# Adjust Max/Min allowed times to fit local time zone and call timegm |
| 158 |
local ($Max{Day}, $Max{Sec}) = _zoneadjust($Max{Day}, $Max{Sec}, $MaxInt); |
| 159 |
local ($Min{Day}, $Min{Sec}) = _zoneadjust($Min{Day}, $Min{Sec}, $MinInt); |
| 160 |
my $ref_t = &timegm; |
| 161 |
|
| 162 |
# Calculate first guess with a one-day delta to avoid localtime overflow |
| 163 |
my $delta = ($_[5] < 100)? 86400 : -86400; |
| 164 |
my $loc_t = _timegm(localtime( $ref_t + $delta )) - $delta; |
| 165 |
|
| 166 |
# Is there a timezone offset from GMT or are we done |
| 167 |
my $zone_off = $ref_t - $loc_t |
| 168 |
or return $loc_t; |
| 169 |
|
| 170 |
# This hack is needed to always pick the first matching time |
| 171 |
# during a DST change when time would otherwise be ambiguous |
| 172 |
$zone_off -= 3600 if ($delta > 0 && $ref_t >= 3600); |
| 173 |
|
| 174 |
# Adjust for timezone |
| 175 |
$loc_t = $ref_t + $zone_off; |
| 176 |
|
| 177 |
# Are we close to a DST change or are we done |
| 178 |
my $dst_off = $ref_t - _timegm(localtime($loc_t)) |
| 179 |
or return $loc_t; |
| 180 |
|
| 181 |
# Adjust for DST change |
| 182 |
$loc_t += $dst_off; |
| 183 |
|
| 184 |
return $loc_t if $dst_off >= 0; |
| 185 |
|
| 186 |
# for a negative offset from GMT, and if the original date |
| 187 |
# was a non-extent gap in a forward DST jump, we should |
| 188 |
# now have the wrong answer - undo the DST adjust; |
| 189 |
|
| 190 |
my ($s,$m,$h) = localtime($loc_t); |
| 191 |
$loc_t -= $dst_off if $s != $_[0] || $m != $_[1] || $h != $_[2]; |
| 192 |
|
| 193 |
$loc_t; |
| 194 |
} |
| 195 |
|
| 196 |
|
| 197 |
sub timelocal_nocheck { |
| 198 |
local $Options{no_range_check} = 1; |
| 199 |
&timelocal; |
| 200 |
} |
| 201 |
|
| 202 |
1; |
| 203 |
|
| 204 |
__END__ |
| 205 |
|
| 206 |
=head1 NAME |
| 207 |
|
| 208 |
Time::Local - efficiently compute time from local and GMT time |
| 209 |
|
| 210 |
=head1 SYNOPSIS |
| 211 |
|
| 212 |
$time = timelocal($sec,$min,$hour,$mday,$mon,$year); |
| 213 |
$time = timegm($sec,$min,$hour,$mday,$mon,$year); |
| 214 |
|
| 215 |
=head1 DESCRIPTION |
| 216 |
|
| 217 |
These routines are the inverse of built-in perl functions localtime() |
| 218 |
and gmtime(). They accept a date as a six-element array, and return |
| 219 |
the corresponding time(2) value in seconds since the system epoch |
| 220 |
(Midnight, January 1, 1970 GMT on Unix, for example). This value can |
| 221 |
be positive or negative, though POSIX only requires support for |
| 222 |
positive values, so dates before the system's epoch may not work on |
| 223 |
all operating systems. |
| 224 |
|
| 225 |
It is worth drawing particular attention to the expected ranges for |
| 226 |
the values provided. The value for the day of the month is the actual day |
| 227 |
(ie 1..31), while the month is the number of months since January (0..11). |
| 228 |
This is consistent with the values returned from localtime() and gmtime(). |
| 229 |
|
| 230 |
The timelocal() and timegm() functions perform range checking on the |
| 231 |
input $sec, $min, $hour, $mday, and $mon values by default. If you'd |
| 232 |
rather they didn't, you can explicitly import the timelocal_nocheck() |
| 233 |
and timegm_nocheck() functions. |
| 234 |
|
| 235 |
use Time::Local 'timelocal_nocheck'; |
| 236 |
|
| 237 |
{ |
| 238 |
# The 365th day of 1999 |
| 239 |
print scalar localtime timelocal_nocheck 0,0,0,365,0,99; |
| 240 |
|
| 241 |
# The twenty thousandth day since 1970 |
| 242 |
print scalar localtime timelocal_nocheck 0,0,0,20000,0,70; |
| 243 |
|
| 244 |
# And even the 10,000,000th second since 1999! |
| 245 |
print scalar localtime timelocal_nocheck 10000000,0,0,1,0,99; |
| 246 |
} |
| 247 |
|
| 248 |
Your mileage may vary when trying these with minutes and hours, |
| 249 |
and it doesn't work at all for months. |
| 250 |
|
| 251 |
Strictly speaking, the year should also be specified in a form consistent |
| 252 |
with localtime(), i.e. the offset from 1900. |
| 253 |
In order to make the interpretation of the year easier for humans, |
| 254 |
however, who are more accustomed to seeing years as two-digit or four-digit |
| 255 |
values, the following conventions are followed: |
| 256 |
|
| 257 |
=over 4 |
| 258 |
|
| 259 |
=item * |
| 260 |
|
| 261 |
Years greater than 999 are interpreted as being the actual year, |
| 262 |
rather than the offset from 1900. Thus, 1964 would indicate the year |
| 263 |
Martin Luther King won the Nobel prize, not the year 3864. |
| 264 |
|
| 265 |
=item * |
| 266 |
|
| 267 |
Years in the range 100..999 are interpreted as offset from 1900, |
| 268 |
so that 112 indicates 2012. This rule also applies to years less than zero |
| 269 |
(but see note below regarding date range). |
| 270 |
|
| 271 |
=item * |
| 272 |
|
| 273 |
Years in the range 0..99 are interpreted as shorthand for years in the |
| 274 |
rolling "current century," defined as 50 years on either side of the current |
| 275 |
year. Thus, today, in 1999, 0 would refer to 2000, and 45 to 2045, |
| 276 |
but 55 would refer to 1955. Twenty years from now, 55 would instead refer |
| 277 |
to 2055. This is messy, but matches the way people currently think about |
| 278 |
two digit dates. Whenever possible, use an absolute four digit year instead. |
| 279 |
|
| 280 |
=back |
| 281 |
|
| 282 |
The scheme above allows interpretation of a wide range of dates, particularly |
| 283 |
if 4-digit years are used. |
| 284 |
|
| 285 |
Please note, however, that the range of dates that can be actually be handled |
| 286 |
depends on the size of an integer (time_t) on a given platform. |
| 287 |
Currently, this is 32 bits for most systems, yielding an approximate range |
| 288 |
from Dec 1901 to Jan 2038. |
| 289 |
|
| 290 |
Both timelocal() and timegm() croak if given dates outside the supported |
| 291 |
range. |
| 292 |
|
| 293 |
=head2 Ambiguous Local Times (DST) |
| 294 |
|
| 295 |
Because of DST changes, there are many time zones where the same local |
| 296 |
time occurs for two different GMT times on the same day. For example, |
| 297 |
in the "Europe/Paris" time zone, the local time of 2001-10-28 02:30:00 |
| 298 |
can represent either 2001-10-28 00:30:00 GMT, B<or> 2001-10-28 |
| 299 |
01:30:00 GMT. |
| 300 |
|
| 301 |
When given an ambiguous local time, the timelocal() function should |
| 302 |
always return the epoch for the I<earlier> of the two possible GMT |
| 303 |
times. |
| 304 |
|
| 305 |
=head2 Non-Existent Local Times (DST) |
| 306 |
|
| 307 |
When a DST change causes a locale clock to skip one hour forward, |
| 308 |
there will be an hour's worth of local times that don't exist. Again, |
| 309 |
for the "Europe/Paris" time zone, the local clock jumped from |
| 310 |
2001-03-25 01:59:59 to 2001-03-25 03:00:00. |
| 311 |
|
| 312 |
If the timelocal() function is given a non-existent local time, it |
| 313 |
will simply return an epoch value for the time one hour later. |
| 314 |
|
| 315 |
=head2 Negative Epoch Values |
| 316 |
|
| 317 |
Negative epoch (time_t) values are not officially supported by the |
| 318 |
POSIX standards, so this module's tests do not test them. On some |
| 319 |
systems, they are known not to work. These include MacOS (pre-OSX) |
| 320 |
and Win32. |
| 321 |
|
| 322 |
On systems which do support negative epoch values, this module should |
| 323 |
be able to cope with dates before the start of the epoch, down the |
| 324 |
minimum value of time_t for the system. |
| 325 |
|
| 326 |
=head1 IMPLEMENTATION |
| 327 |
|
| 328 |
These routines are quite efficient and yet are always guaranteed to agree |
| 329 |
with localtime() and gmtime(). We manage this by caching the start times |
| 330 |
of any months we've seen before. If we know the start time of the month, |
| 331 |
we can always calculate any time within the month. The start times |
| 332 |
are calculated using a mathematical formula. Unlike other algorithms |
| 333 |
that do multiple calls to gmtime(). |
| 334 |
|
| 335 |
timelocal() is implemented using the same cache. We just assume that we're |
| 336 |
translating a GMT time, and then fudge it when we're done for the timezone |
| 337 |
and daylight savings arguments. Note that the timezone is evaluated for |
| 338 |
each date because countries occasionally change their official timezones. |
| 339 |
Assuming that localtime() corrects for these changes, this routine will |
| 340 |
also be correct. |
| 341 |
|
| 342 |
=head1 BUGS |
| 343 |
|
| 344 |
The whole scheme for interpreting two-digit years can be considered a bug. |
| 345 |
|
| 346 |
=head1 SUPPORT |
| 347 |
|
| 348 |
Support for this module is provided via the datetime@perl.org |
| 349 |
email list. See http://lists.perl.org/ for more details. |
| 350 |
|
| 351 |
Please submit bugs using the RT system at rt.cpan.org, or as a last |
| 352 |
resort, to the datetime@perl.org list. |
| 353 |
|
| 354 |
=head1 AUTHOR |
| 355 |
|
| 356 |
This module is based on a Perl 4 library, timelocal.pl, that was |
| 357 |
included with Perl 4.036, and was most likely written by Tom |
| 358 |
Christiansen. |
| 359 |
|
| 360 |
The current version was written by Graham Barr. |
| 361 |
|
| 362 |
It is now being maintained separately from the Perl core by Dave |
| 363 |
Rolsky, <autarch@urth.org>. |
| 364 |
|
| 365 |
=cut |
| 366 |
|
