use Time::JulianDay;

my @start = (1981, 2, 1);
my @end   = (1982, 2, 5);
my $days = days('start' => \@start, 'end' => \@end, 'type' => 'yearly');
my $days = days('start' => \@start, 'end' => \@end, 'type' => 'range');

sub days {
	my (%a) = @_;
	
	my ($start, $end, $type) = ($a{'start'}, $a{'end'}, $a{'type'});
	
	if ($type eq 'range') {
		my $j0 = julian_day(1980, 1, 1);
		my $j1 = julian_day(@$start);
		my $j2 = julian_day(@$end);
		
		return (($j1 - $j0), ($j2 - $j0));
	}
	elsif ($type eq 'yearly') {
		my $start_year = $start->[0];
		my $end_year = $end->[0];
		
		my %days;
		for my $year ($start_year .. $end_year) {
			my $j0 = julian_day($year, 1, 1);
			my $j1; my $j2;
			if ($year == $start_year) {
				$j1 = julian_day($year, $start->[1], $start->[2]);
				$j2 = julian_day($year, 12, 31);
			}
			elsif ($year == $end_year) {
				$j1 = julian_day($year, 1, 1);
				$j2 = julian_day($year, $end->[1], $end->[2]);			
			}
			else {
				$j1 = julian_day($year, 1, 1);
				$j2 = julian_day($year, 12, 31);
			}
			
			$days{"$year"} = [($j1 - $j0) .. ($j2 - $j0)];
		}
		
		return \%days;
	}
}