#/usr/bin/perl

#####################################################################################
#######              computerzeit.pl V0.01                       #####
#######          2002 copyleft martin krung                      #####			
#######	 martin at krungkuene dot org martin at krung dot org    #####
#####################################################################################



if ($ARGV[2] == undef ){
print "\nProgram aborted : too less argumentes.\n";
print "Programm vorzeitig beendet : zuwenig Argumente.\n\n";

print "Argumentes:\n\n";

print "number_of_different_characters number_of_digits combinations_per_second\n\n";
print "eg: perl computerzeit.pl 58 8 70000 \n\n";

print "Argumente:\n\n";
print "anzahl_verschiedener_zeichen anzahl_stellen kombinationen_pro_sekunde\n\n";
print "zb: perl computerzeit.pl 58 8 70000 \n";

exit;
};

# ---------input----------------------------------------------------------------------------------
# ------------------------------------------------------------------------------------------------

$diffchar = $ARGV[0];
$pwstellen = $ARGV[1];
$c_p_s= $ARGV[2];

# -----------calculation--------------------------------------------------------------------------
# ------------------------------------------------------------------------------------------------

$combination = $diffchar ** $pwstellen;

$ts = $combination/$c_p_s;

$th = $ts / 3600;

$td = $th / 24;
$tw = $td / 7;
$ty = $td / 356;

# this is only guessed, beause i know a 64 bit DES encrypted password needs 13 bytes
$MB = ($combination * ($pw_stellen + 13))/ (1024*1024);
$GB = $MB / 1024;
$TB = $GB / 1024;





# ------------------------------------------------------------------------------------------------
# -----the following funtions are for better readability of the output ---------------------------

$ts = space_num(eval(int($ts)));
$maxdigit = length($ts);

#add space every 3 digit, it s better readable

sub space_num{
my $num = $_[0];
$num = reverse($num);
$num =~ s/(.{3})/$1 /g;
$num = reverse($num);

#remove the leading space, if there is any.
#this took my several hours, if you know better,
#or even one regexp for all, please mail me !

$num =~ s/^ {1}//;
return($num);
}

# make the digits rightbound, for better readability too

sub right_num{
my $num = $_[0];
my $maxdigit = $_[1];
my $num_lenght = length("$num");
$loops = $maxdigit - $num_lenght;
for ($i=0; $i < $loops; $i++){
$num = " ".$num;
}
return($num);
}

# both in one step

sub show_digit{
my $num = $_[0];
$num = space_num(eval(int($num)));
$num = right_num($num,$maxdigit);
return($num);
}

# ---Output----german---------------------------------------------------------------------------



print "\n ----------- INFO ------------------------------------------ \n\n";

print "There are ".space_num($combination)." differently combinations.\n";
print "Es gibt ".space_num($combination)." verschieden Kombinationen. \n\n";

print "With ".space_num($c_p_s)." combinations per second it needs :\n";
print "Bei ".space_num($c_p_s)." Kombinationen pro Sekunde braucht es :\n\n";


print $ts." seconds / Sekunden\n";

print show_digit($th)." houres  / Stunden \n";
print show_digit($td)." days    / Tagen \n";
print show_digit($tw)." weeks   / Wochen  \n";
print show_digit($ty)." years   / Jahre \n\n";

print "To save all this combinations on harddisk it needs :\n";
print "Um all diese Kombinationen zu speicher braucht es :\n\n";

print  show_digit($GB)." GigaBytes\n";
print  show_digit($TB)." TeraBytes\n\n";


print "\n ---------------------------------------------------------- \n\n";