use Storable;
use File::Flat;

my @to_save;
my $nrows=10000;
my $rowmax=300;

for (0..$nrows) {
  my @r;
  $r[0]=int(rand(20));
  for (1..int(rand($rowmax))) {
    push @r, $r[$_-1] + 1 + int(rand(200));
  }
  push @to_save, join ',',@r;
}

my $in="";
foreach( @to_save ) {
  $in .= $_."\n";
  my @a = sort {$a<=>$b} split/,/;
  my $d=0;
  for( @a ){ ($d,$_)=($_,$_-$d); }
  $_ = pack'w*',@a;
}

open(TEXT, ">array.txt") or die "Can't open output file";
print TEXT $in;
close TEXT;

store (\@to_save, 'array.sto');

my $to_retrieve= retrieve ('array.sto');
my $out="";
foreach( @$to_retrieve ) {
  my @a = unpack'w*',$_;
  my $c = 0;
  foreach my $n (@a) {
    $c += $n;
    $out .= $c.",";
  }
  chop $out;
  $out .= "\n";
}

if ($in eq $out) {
  print "OK\n"
}

my $sz_in= File::Flat->fileSize('array.txt')
             or die "Can't size array.txt";
my $sz_out= File::Flat->fileSize('array.sto')
             or die "Can't size array.sto";

print "Final size = ",int(100*$sz_out/$sz_in+0.5),"% of input\n";