1*abb0f93cSkardel;# timelocal.pl 2*abb0f93cSkardel;# 3*abb0f93cSkardel;# Usage: 4*abb0f93cSkardel;# $time = timelocal($sec,$min,$hours,$mday,$mon,$year,$junk,$junk,$isdst); 5*abb0f93cSkardel;# $time = timegm($sec,$min,$hours,$mday,$mon,$year); 6*abb0f93cSkardel 7*abb0f93cSkardel;# These routines are quite efficient and yet are always guaranteed to agree 8*abb0f93cSkardel;# with localtime() and gmtime(). We manage this by caching the start times 9*abb0f93cSkardel;# of any months we've seen before. If we know the start time of the month, 10*abb0f93cSkardel;# we can always calculate any time within the month. The start times 11*abb0f93cSkardel;# themselves are guessed by successive approximation starting at the 12*abb0f93cSkardel;# current time, since most dates seen in practice are close to the 13*abb0f93cSkardel;# current date. Unlike algorithms that do a binary search (calling gmtime 14*abb0f93cSkardel;# once for each bit of the time value, resulting in 32 calls), this algorithm 15*abb0f93cSkardel;# calls it at most 6 times, and usually only once or twice. If you hit 16*abb0f93cSkardel;# the month cache, of course, it doesn't call it at all. 17*abb0f93cSkardel 18*abb0f93cSkardel;# timelocal is implemented using the same cache. We just assume that we're 19*abb0f93cSkardel;# translating a GMT time, and then fudge it when we're done for the timezone 20*abb0f93cSkardel;# and daylight savings arguments. The timezone is determined by examining 21*abb0f93cSkardel;# the result of localtime(0) when the package is initialized. The daylight 22*abb0f93cSkardel;# savings offset is currently assumed to be one hour. 23*abb0f93cSkardel 24*abb0f93cSkardelCONFIG: { 25*abb0f93cSkardel package timelocal; 26*abb0f93cSkardel 27*abb0f93cSkardel @epoch = localtime(0); 28*abb0f93cSkardel $tzmin = $epoch[2] * 60 + $epoch[1]; # minutes east of GMT 29*abb0f93cSkardel if ($tzmin > 0) { 30*abb0f93cSkardel $tzmin = 24 * 60 - $tzmin; # minutes west of GMT 31*abb0f93cSkardel $tzmin -= 24 * 60 if $epoch[5] == 70; # account for the date line 32*abb0f93cSkardel } 33*abb0f93cSkardel 34*abb0f93cSkardel $SEC = 1; 35*abb0f93cSkardel $MIN = 60 * $SEC; 36*abb0f93cSkardel $HR = 60 * $MIN; 37*abb0f93cSkardel $DAYS = 24 * $HR; 38*abb0f93cSkardel $YearFix = ((gmtime(946684800))[5] == 100) ? 100 : 0; 39*abb0f93cSkardel} 40*abb0f93cSkardel 41*abb0f93cSkardelsub timegm { 42*abb0f93cSkardel package timelocal; 43*abb0f93cSkardel 44*abb0f93cSkardel $ym = pack(C2, @_[5,4]); 45*abb0f93cSkardel $cheat = $cheat{$ym} || &cheat; 46*abb0f93cSkardel $cheat + $_[0] * $SEC + $_[1] * $MIN + $_[2] * $HR + ($_[3]-1) * $DAYS; 47*abb0f93cSkardel} 48*abb0f93cSkardel 49*abb0f93cSkardelsub timelocal { 50*abb0f93cSkardel package timelocal; 51*abb0f93cSkardel 52*abb0f93cSkardel $ym = pack(C2, @_[5,4]); 53*abb0f93cSkardel $cheat = $cheat{$ym} || &cheat; 54*abb0f93cSkardel $cheat + $_[0] * $SEC + $_[1] * $MIN + $_[2] * $HR + ($_[3]-1) * $DAYS 55*abb0f93cSkardel + $tzmin * $MIN - 60 * 60 * ($_[8] != 0); 56*abb0f93cSkardel} 57*abb0f93cSkardel 58*abb0f93cSkardelpackage timelocal; 59*abb0f93cSkardel 60*abb0f93cSkardelsub cheat { 61*abb0f93cSkardel $year = $_[5]; 62*abb0f93cSkardel $month = $_[4]; 63*abb0f93cSkardel $guess = $^T; 64*abb0f93cSkardel @g = gmtime($guess); 65*abb0f93cSkardel $year += $YearFix if $year < $epoch[5]; 66*abb0f93cSkardel while ($diff = $year - $g[5]) { 67*abb0f93cSkardel $guess += $diff * (364 * $DAYS); 68*abb0f93cSkardel @g = gmtime($guess); 69*abb0f93cSkardel } 70*abb0f93cSkardel while ($diff = $month - $g[4]) { 71*abb0f93cSkardel $guess += $diff * (28 * $DAYS); 72*abb0f93cSkardel @g = gmtime($guess); 73*abb0f93cSkardel } 74*abb0f93cSkardel $g[3]--; 75*abb0f93cSkardel $guess -= $g[0] * $SEC + $g[1] * $MIN + $g[2] * $HR + $g[3] * $DAYS; 76*abb0f93cSkardel $cheat{$ym} = $guess; 77*abb0f93cSkardel} 78