sub compress_uint {
   my ($uint) = @_;
   my $compressed = '';
   while ($uint >= 128) {
      $compressed .= chr(($uint & 127) | 128);
      $uint >>= 7;
   }
   $compressed .= chr($uint);
}

for (100, 1000, 100000) {
   print $fh compress_uint($_);
}