return _pos_to_square($from_row, $from_col) . _pos_to_square($to_row, $to_col) . $promo;
}
+# Note: This is in general not a validation that the move is actually allowed
+# (e.g. you can castle even though you're in check).
sub parse_pretty_move {
my ($board, $move, $toplay) = @_;
for my $col (0..7) {
next if (defined($from_col) && $from_col != $col);
next if ($board->[$row][$col] ne $piece);
- next if (!$board->can_reach($piece, $row, $col, $to_row, $to_col));
-
- # See if doing this move would put us in check
- # (yes, there are clients that expect us to do this).
- next if ($board->make_move($row, $col, $to_row, $to_col, $promo)->in_check($side));
push @squares, [ $row, $col ];
}
}
+ if (scalar @squares > 1) {
+ # Filter out pieces which cannot reach this square.
+ @squares = grep { $board->can_reach($piece, $_->[0], $_->[1], $to_row, $to_col) } @squares;
+ }
+ if (scalar @squares > 1) {
+ # See if doing this move would put us in check
+ # (yes, there are clients that expect us to do this).
+ @squares = grep { !$board->make_move($_->[0], $_->[1], $to_row, $to_col, $promo)->in_check($side) } @squares;
+ }
+ if (scalar @squares == 0) {
+ die "Impossible move $move";
+ }
if (scalar @squares != 1) {
- die "Ambigious or impossible move $move";
+ die "Ambigious move $move";
}
return (@{$squares[0]}, $to_row, $to_col, $promo);
}
return join('/', @rows);
}
+# Returns a compact bit string describing the same data as fen().
+# This is encoded using a Huffman-like encoding, and should be
+# typically about 1/3 the number of bytes.
+sub bitpacked_fen {
+ my ($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*', $bits);
+}
+
sub can_reach {
my ($board, $piece, $from_row, $from_col, $to_row, $to_col) = @_;