my @ones = (0);
  push @ones, map $_ + 1, @ones for 1 .. 8;
  my @zeros = map 8 - $_, @ones;
  ...
  read($fh, $buf, 1) or die ...;
  my $val = ord($buf);
  printf "%08b has %s ones and %s zeros\n", $val, $ones[$val], $zeros[$val];