-# Returns a compact bit string describing the same data as fen().
-# This is encoded using a Huffman-like encoding, and should be
-# typically about 1/3 the number of bytes.
-sub bitpacked_fen {
- my ($board) = @_;
- my $bits = "";
-
- for my $row (0..7) {
- for my $col (0..7) {
- my $piece = $board->[$row][$col];
- if ($piece eq '-') {
- $bits .= "0";
- next;
- }
-
- my $color = (lc($piece) eq $piece) ? 0 : 1;
- $bits .= "1" . $color;
-
- if (lc($piece) eq 'p') {
- $bits .= "0";
- } elsif (lc($piece) eq 'n') {
- $bits .= "100";
- } elsif (lc($piece) eq 'b') {
- $bits .= "101";
- } elsif (lc($piece) eq 'r') {
- $bits .= "1110";
- } elsif (lc($piece) eq 'q') {
- $bits .= "11110";
- } elsif (lc($piece) eq 'k') {
- $bits .= "11111";
- } else {
- die "Unknown piece $piece";
- }
- }
- }
-
- return pack('b*', $bits);
-}
-