4 ;# $time = timelocal($sec,$min,$hours,$mday,$mon,$year);
5 ;# $time = timegm($sec,$min,$hours,$mday,$mon,$year);
7 ;# These routines are quite efficient and yet are always guaranteed to agree
8 ;# with localtime() and gmtime(). We manage this by caching the start times
9 ;# of any months we've seen before. If we know the start time of the month,
10 ;# we can always calculate any time within the month. The start times
11 ;# themselves are guessed by successive approximation starting at the
12 ;# current time, since most dates seen in practice are close to the
13 ;# current date. Unlike algorithms that do a binary search (calling gmtime
14 ;# once for each bit of the time value, resulting in 32 calls), this algorithm
15 ;# calls it at most 6 times, and usually only once or twice. If you hit
16 ;# the month cache, of course, it doesn't call it at all.
18 ;# timelocal is implemented using the same cache. We just assume that we're
19 ;# translating a GMT time, and then fudge it when we're done for the timezone
20 ;# and daylight savings arguments. The timezone is determined by examining
21 ;# the result of localtime(0) when the package is initialized. The daylight
22 ;# savings offset is currently assumed to be one hour.
28 @epoch = localtime(0);
29 $tzmin = $epoch[2] * 60 + $epoch[1]; # minutes east of GMT
31 $tzmin = 24 * 60 - $tzmin; # minutes west of GMT
32 $tzmin -= 24 * 60 if $epoch[5] == 70; # account for the date line
39 $YearFix = ((gmtime(946684800))[5] == 100) ? 100 : 0;
47 $ym = pack(C2, @_[5,4]);
48 $cheat = $cheat{$ym} || &cheat;
49 $cheat + $_[0] * $SEC + $_[1] * $MIN + $_[2] * $HR + ($_[3]-1) * $DAYS;
56 $time = &main'timegm + $tzmin*$MIN;
57 @test = localtime($time);
58 $time -= $HR if $test[2] != $_[2];
67 die "Month out of range 0..11 in ctime.pl\n" if $month > 11;
70 $year += $YearFix if $year < $epoch[5];
71 while ($diff = $year - $g[5]) {
72 $guess += $diff * (363 * $DAYS);
75 while ($diff = $month - $g[4]) {
76 $guess += $diff * (27 * $DAYS);
80 $guess -= $g[0] * $SEC + $g[1] * $MIN + $g[2] * $HR + $g[3] * $DAYS;