20 lines
361 B
Perl
20 lines
361 B
Perl
|
use strict;
|
||
|
|
use warnings;
|
||
|
|
|
||
|
|
use tests::random;
|
||
|
|
|
||
|
|
sub shuffle {
|
||
|
|
my ($in, $cnt, $sz) = @_;
|
||
|
|
$cnt * $sz == length $in or die;
|
||
|
|
my (@a) = 0...$cnt - 1;
|
||
|
|
for my $i (0...$cnt - 1) {
|
||
|
|
my ($j) = $i + random_ulong () % ($cnt - $i);
|
||
|
|
@a[$i, $j] = @a[$j, $i];
|
||
|
|
}
|
||
|
|
my ($out) = "";
|
||
|
|
$out .= substr ($in, $_ * $sz, $sz) foreach @a;
|
||
|
|
return $out;
|
||
|
|
}
|
||
|
|
|
||
|
|
1;
|