Small microoptimization in in_check; do not go through a row unless it has attacking...

diff --git a/Board.pm b/Board.pm
index 1bedd56a23d704f458384a858f69b4120cf652d4..7e120053144691af3edaf0377f7446ab7f5f7e79 100644 (file)
--- a/Board.pm
+++ b/Board.pm
@@ -336,13 +336,19 @@ sub can_reach {
        return 0;
 }
 
+my %pieces_against_side = (
+       k => { K => 1, Q => 1, R => 1, N => 1, B => 1, P => 1 },
+       K => { k => 1, q => 1, r => 1, n => 1, b => 1, p => 1 },
+);
+
 # Returns whether the given side (given as k or K for black and white) is in check.
 sub in_check {
-       my ($board, $piece) = @_;
-       my ($kr, $kc) = _find_piece($board, $piece);
+       my ($board, $side) = @_;
+       my ($kr, $kc) = _find_piece($board, $side);
 
        # check all pieces for the possibility of threatening this king
        for my $row (0..7) {
+               next unless grep { exists($pieces_against_side{$side}{$_}) } @{$board->[$row]};
                for my $col (0..7) {
                        my $piece = $board->[$row][$col];
                        next if ($piece eq '-');