X-Git-Url: https://git.sesse.net/?p=remoteglot;a=blobdiff_plain;f=Board.pm;h=d2a6e0e425f7b48c8584c47e07e1692fd42ab604;hp=2edc07de0c61a37b93ebee9e5aadd73fe29985e2;hb=0a124edc28c716548327826127a9145da091a3d0;hpb=2e02751eebe4f5ed406e0f61c6f6eadae0193a41

diff --git a/Board.pm b/Board.pm
index 2edc07d..d2a6e0e 100644
--- a/Board.pm
+++ b/Board.pm
@@ -200,8 +200,11 @@ sub parse_pretty_move {
 			push @squares, [ $row, $col ];
 		}
 	}
+	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);
 }
@@ -218,6 +221,45 @@ sub fen {
 	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) = @_;