diff options
author | Jason Downs <downsj@cvs.openbsd.org> | 1996-08-19 10:13:38 +0000 |
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committer | Jason Downs <downsj@cvs.openbsd.org> | 1996-08-19 10:13:38 +0000 |
commit | 14856225739aa48b6c9cf4c17925362b2d95cea3 (patch) | |
tree | dfd38f1b654fb5bbdfc38887c1a829b658e71530 /gnu/usr.bin/perl/lib/Time | |
parent | 77469082517e44fe6ca347d9e8dc7dffd1583637 (diff) |
Import of Perl 5.003 into the tree. Makefile.bsd-wrapper and
config.sh.OpenBSD are the only local changes.
Diffstat (limited to 'gnu/usr.bin/perl/lib/Time')
-rw-r--r-- | gnu/usr.bin/perl/lib/Time/Local.pm | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/gnu/usr.bin/perl/lib/Time/Local.pm b/gnu/usr.bin/perl/lib/Time/Local.pm new file mode 100644 index 00000000000..451c7fa20c7 --- /dev/null +++ b/gnu/usr.bin/perl/lib/Time/Local.pm @@ -0,0 +1,112 @@ +package Time::Local; +require 5.000; +require Exporter; +use Carp; + +@ISA = qw(Exporter); +@EXPORT = qw(timegm timelocal); + +=head1 NAME + +Time::Local - efficiently compute tome from local and GMT time + +=head1 SYNOPSIS + + $time = timelocal($sec,$min,$hours,$mday,$mon,$year); + $time = timegm($sec,$min,$hours,$mday,$mon,$year); + +=head1 DESCRIPTION + +These routines are quite efficient and yet are always guaranteed to agree +with localtime() and gmtime(). We manage this by caching the start times +of any months we've seen before. If we know the start time of the month, +we can always calculate any time within the month. The start times +themselves are guessed by successive approximation starting at the +current time, since most dates seen in practice are close to the +current date. Unlike algorithms that do a binary search (calling gmtime +once for each bit of the time value, resulting in 32 calls), this algorithm +calls it at most 6 times, and usually only once or twice. If you hit +the month cache, of course, it doesn't call it at all. + +timelocal is implemented using the same cache. We just assume that we're +translating a GMT time, and then fudge it when we're done for the timezone +and daylight savings arguments. The timezone is determined by examining +the result of localtime(0) when the package is initialized. The daylight +savings offset is currently assumed to be one hour. + +Both routines return -1 if the integer limit is hit. I.e. for dates +after the 1st of January, 2038 on most machines. + +=cut + +@epoch = localtime(0); +$tzmin = $epoch[2] * 60 + $epoch[1]; # minutes east of GMT +if ($tzmin > 0) { + $tzmin = 24 * 60 - $tzmin; # minutes west of GMT + $tzmin -= 24 * 60 if $epoch[5] == 70; # account for the date line +} + +$SEC = 1; +$MIN = 60 * $SEC; +$HR = 60 * $MIN; +$DAYS = 24 * $HR; +$YearFix = ((gmtime(946684800))[5] == 100) ? 100 : 0; + +sub timegm { + $ym = pack(C2, @_[5,4]); + $cheat = $cheat{$ym} || &cheat; + return -1 if $cheat<0; + $cheat + $_[0] * $SEC + $_[1] * $MIN + $_[2] * $HR + ($_[3]-1) * $DAYS; +} + +sub timelocal { + $time = &timegm + $tzmin*$MIN; + return -1 if $cheat<0; + @test = localtime($time); + $time -= $HR if $test[2] != $_[2]; + $time; +} + +sub cheat { + $year = $_[5]; + $month = $_[4]; + croak "Month out of range 0..11 in timelocal.pl" + if $month > 11 || $month < 0; + croak "Day out of range 1..31 in timelocal.pl" + if $_[3] > 31 || $_[3] < 1; + croak "Hour out of range 0..23 in timelocal.pl" + if $_[2] > 23 || $_[2] < 0; + croak "Minute out of range 0..59 in timelocal.pl" + if $_[1] > 59 || $_[1] < 0; + croak "Second out of range 0..59 in timelocal.pl" + if $_[0] > 59 || $_[0] < 0; + $guess = $^T; + @g = gmtime($guess); + $year += $YearFix if $year < $epoch[5]; + $lastguess = ""; + while ($diff = $year - $g[5]) { + $guess += $diff * (363 * $DAYS); + @g = gmtime($guess); + if (($thisguess = "@g") eq $lastguess){ + return -1; #date beyond this machine's integer limit + } + $lastguess = $thisguess; + } + while ($diff = $month - $g[4]) { + $guess += $diff * (27 * $DAYS); + @g = gmtime($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] * $DAYS; + $cheat{$ym} = $guess; +} + +1; |