#!/usr/bin/perl -w
my $usage = "Usage: $0 -a [-][hh:][mm:]ss";

use Date::Calc qw( Decode_Date_US Add_Delta_DHMS Delta_DHMS);

my($option,$adj) = (shift,shift);
$option eq "-a"				or die $usage;
my ($adjsec) = &hhmmss_toseconds($adj)	or die $usage;
print STDERR "adjusting by $adjsec seconds\n";
while(<>) {
###	48778 Thu Feb 22 15:42:39 2001 546.jpg
	chomp;
	my ($size,$day,$mo,$date,$time,$year,$file) = split;
###	print STDERR "time is $time\n";
	my ($timesec) = &hhmmss_toseconds($time);
###	print STDERR "timesec is $timesec\n";
	($time) = &seconds_tohmmss($timesec+$adjsec);
	print join(' ',$size,$day,$mo,$date,$time,$year,$file),"\n";
}
exit;

sub hhmmss_toseconds {
my ($t) = @_;
my $sign = ($t =~ s|^\s*-||) ? -1 : +1;
if ($t =~ m|^([\d]+):([\d]+):([\d\.]+)$|) {
	$t = 3600*$1 + 60*$2 + $3;
} elsif ($t =~ m|^([\d]+):([\d\.]+)$|) {
	$t = 60*$1 + $2;
} else {
	die "hhmmss_toseconds: bad arg <$t> sign <$sign>";
}
return ($sign*$t);
}

sub seconds_tohmmss {
my ($t) = @_;
### print STDERR  "stoh: $t\n";
my (undef,undef,$day,$hour,$minute,$second) = Add_Delta_DHMS(1,1,1,0,0,0,0,0,0,$t);
return (sprintf("%02i:%02i:%02i",$hour,$minute,$second));
if($hour) {
	$t = sprintf("%i:%02i:%02i",$hour,$minute,$second)
} elsif ($minute) {
	$t = sprintf("%i:%02i",$minute,$second)
} else {
	$t = sprintf("%i",$second)
} 
return ($t);
}

sub pretty_date {
return (join('/',$_[1],$_[2],$_[0]).' '.sprintf("%02i:%02i:%02i",@_[3..$#_]));
}