X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FTime%2FLocal.pm;h=0119f9ddb8f0ed3a4705f50865f1664655aee2b2;hb=b133f4ec823b00faf9bd083e0eb8e7a53ba7bfca;hp=64e62405f723421327dd4190a29820ffb644c19a;hpb=a0d0e21ea6ea90a22318550944fe6cb09ae10cda;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/lib/Time/Local.pm b/lib/Time/Local.pm
index 64e6240..0119f9d 100644
--- a/lib/Time/Local.pm
+++ b/lib/Time/Local.pm
@@ -6,55 +6,78 @@ use Carp;
 @ISA = qw(Exporter);
 @EXPORT = qw(timegm timelocal);
 
-# timelocal.pl
-#
-# Usage:
-#	$time = timelocal($sec,$min,$hours,$mday,$mon,$year);
-#	$time = timegm($sec,$min,$hours,$mday,$mon,$year);
-
-# These routines are quite efficient and yet are always guaranteed to agree
-# with localtime() and gmtime().  We manage this by caching the start times
-# of any months we've seen before.  If we know the start time of the month,
-# we can always calculate any time within the month.  The start times
-# themselves are guessed by successive approximation starting at the
-# current time, since most dates seen in practice are close to the
-# current date.  Unlike algorithms that do a binary search (calling gmtime
-# once for each bit of the time value, resulting in 32 calls), this algorithm
-# calls it at most 6 times, and usually only once or twice.  If you hit
-# the month cache, of course, it doesn't call it at all.
-
-# timelocal is implemented using the same cache.  We just assume that we're
-# translating a GMT time, and then fudge it when we're done for the timezone
-# and daylight savings arguments.  The timezone is determined by examining
-# the result of localtime(0) when the package is initialized.  The daylight
-# savings offset is currently assumed to be one hour.
-
-# Both routines return -1 if the integer limit is hit. I.e. for dates
-# after the 1st of January, 2038 on most machines.
-
-@epoch = localtime(0);
-$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
-}
+=head1 NAME
+
+Time::Local - efficiently compute time 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
 
-$SEC = 1;
-$MIN = 60 * $SEC;
-$HR = 60 * $MIN;
-$DAYS = 24 * $HR;
-$YearFix = ((gmtime(946684800))[5] == 100) ? 100 : 0;
+BEGIN {
+    $SEC  = 1;
+    $MIN  = 60 * $SEC;
+    $HR   = 60 * $MIN;
+    $DAY  = 24 * $HR;
+    $epoch = (localtime(2*$DAY))[5];	# Allow for bugs near localtime == 0.
+
+    $YearFix = ((gmtime(946684800))[5] == 100) ? 100 : 0;
+
+    my $t = time;
+    my @lt = localtime($t);
+    my @gt = gmtime($t);
+
+    $tzsec = ($gt[1] - $lt[1]) * $MIN + ($gt[2] - $lt[2]) * $HR;
+
+    my($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;
+    }
+
+  $tzsec += $HR if($lt[8]);
+}
 
 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;
+    return -1 if $cheat<0 and $^O ne 'VMS';
+    $cheat + $_[0] * $SEC + $_[1] * $MIN + $_[2] * $HR + ($_[3]-1) * $DAY;
 }
 
 sub timelocal {
-    $time = &timegm + $tzmin*$MIN;
-    return -1 if $cheat<0;
+    $time = &timegm + $tzsec;
+    return -1 if $cheat<0 and $^O ne 'VMS';
     @test = localtime($time);
     $time -= $HR if $test[2] != $_[2];
     $time;
@@ -62,23 +85,20 @@ sub timelocal {
 
 sub cheat {
     $year = $_[5];
+    $year -= 1900
+    	if $year > 1900;
     $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 || $_[0] < 0;
+    croak "Month '$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[5];
+    $year += $YearFix if $year < $epoch;
     $lastguess = "";
     while ($diff = $year - $g[5]) {
-	$guess += $diff * (363 * $DAYS);
+	$guess += $diff * (363 * $DAY);
 	@g = gmtime($guess);
 	if (($thisguess = "@g") eq $lastguess){
 	    return -1; #date beyond this machine's integer limit
@@ -86,7 +106,7 @@ sub cheat {
 	$lastguess = $thisguess;
     }
     while ($diff = $month - $g[4]) {
-	$guess += $diff * (27 * $DAYS);
+	$guess += $diff * (27 * $DAY);
 	@g = gmtime($guess);
 	if (($thisguess = "@g") eq $lastguess){
 	    return -1; #date beyond this machine's integer limit
@@ -98,7 +118,7 @@ sub cheat {
 	return -1; #date beyond this machine's integer limit
     }
     $g[3]--;
-    $guess -= $g[0] * $SEC + $g[1] * $MIN + $g[2] * $HR + $g[3] * $DAYS;
+    $guess -= $g[0] * $SEC + $g[1] * $MIN + $g[2] * $HR + $g[3] * $DAY;
     $cheat{$ym} = $guess;
 }