#!/usr/bin/perl

use Time::Local;

# check for DST adjustments in 2007.
# Begins 3/11, ends 11/4.
# On each day, check 1AM, then check 1AM+1hr (as opposed to 2AM)
# Convert back to dates and compare hours.
#
# David Torrey <tj@mtu.edu>

%checks = ( # deltaHour => dateStrList
	2 => [ '3/11/2007' ], # spring forward = 1AM,3AM
	0 => [ '11/4/2007' ]  # fall back = 1AM,1AM
);

foreach $timechange (keys %checks) {

	my @dates = @{$checks{$timechange}};

	foreach $date (@dates) {

		my ($month, $day, $year) = split(/\//,$date);
		# cheat by adding a day's worth of seconds.
		$oneAM = timelocal(0,0,1,$day,$month-1,$year);

		$oneAMhour = (localtime($oneAM))[2];
		$twoAMhour = (localtime($oneAM+3600))[2];

		$delta = $twoAMhour - $oneAMhour;

		if($delta == $timechange) {

			print "$date: change okay\n";

		} else {

			print "$date: not correct\n";

		}

	}

}