+ my $json = { %$pos, fen => $pos->fen() };
+ delete $json->{'board'};
+ delete $json->{'prettyprint_cache'};
+ delete $json->{'black_castle_k'};
+ delete $json->{'black_castle_q'};
+ delete $json->{'white_castle_k'};
+ delete $json->{'white_castle_q'};
+ delete $json->{'time_since_100move_rule_reset'};
+ if ($json->{'player_w'} =~ /^base64:(.*)$/) {
+ $json->{'player_w'} = MIME::Base64::decode_base64($1);
+ }
+ if ($json->{'player_b'} =~ /^base64:(.*)$/) {
+ $json->{'player_b'} = MIME::Base64::decode_base64($1);
+ }
+ return $json;
+}
+
+sub parse_pretty_move {
+ my ($pos, $move) = @_;
+ return $pos->{'board'}->parse_pretty_move($move, $pos->{'toplay'});
+}
+
+sub num_pieces {
+ my ($pos) = @_;
+ return $pos->{'board'}->num_pieces();
+}
+
+# Returns a new Position object.
+sub make_move {
+ my ($pos, $from_row, $from_col, $to_row, $to_col, $promo, $pretty_move) = @_;
+
+ my $from_square = _pos_to_square($from_row, $from_col);
+ my $to_square = _pos_to_square($to_row, $to_col);
+
+ my $np = {};
+ $np->{'board'} = $pos->{'board'}->make_move($from_row, $from_col, $to_row, $to_col, $promo);
+ if ($pos->{'toplay'} eq 'W') {
+ $np->{'toplay'} = 'B';
+ $np->{'move_num'} = $pos->{'move_num'};
+ } else {
+ $np->{'toplay'} = 'W';
+ $np->{'move_num'} = $pos->{'move_num'} + 1;
+ }
+
+ my $piece = $pos->{'board'}[$from_row][$from_col];
+ my $dest_piece = $pos->{'board'}[$to_row][$to_col];
+
+ # Find out if this was a two-step pawn move.
+ if (lc($piece) eq 'p' && abs($from_row - $to_row) == 2) {
+ $np->{'ep_file_num'} = $from_col;
+ } else {
+ $np->{'ep_file_num'} = -1;
+ }
+
+ # Castling rights.
+ $np->{'white_castle_k'} = $pos->{'white_castle_k'};
+ $np->{'white_castle_q'} = $pos->{'white_castle_q'};
+ $np->{'black_castle_k'} = $pos->{'black_castle_k'};
+ $np->{'black_castle_q'} = $pos->{'black_castle_q'};
+ if ($piece eq 'K') {
+ $np->{'white_castle_k'} = 0;
+ $np->{'white_castle_q'} = 0;
+ } elsif ($piece eq 'k') {
+ $np->{'black_castle_k'} = 0;
+ $np->{'black_castle_q'} = 0;
+ } elsif ($from_square eq 'a1' || $to_square eq 'a1') {
+ $np->{'white_castle_q'} = 0;
+ } elsif ($from_square eq 'h1' || $to_square eq 'h1') {
+ $np->{'white_castle_k'} = 0;
+ } elsif ($from_square eq 'a8' || $to_square eq 'a8') {
+ $np->{'black_castle_q'} = 0;
+ } elsif ($from_square eq 'h8' || $to_square eq 'h8') {
+ $np->{'black_castle_k'} = 0;
+ }
+
+ # 50-move rule.
+ if (lc($piece) eq 'p' || $dest_piece ne '-') {
+ $np->{'time_since_100move_rule_reset'} = 0;
+ } else {
+ $np->{'time_since_100move_rule_reset'} = $pos->{'time_since_100move_rule_reset'} + 1;
+ }
+ $np->{'player_w'} = $pos->{'player_w'};
+ $np->{'player_b'} = $pos->{'player_b'};
+ if (defined($pretty_move)) {
+ $np->{'last_move'} = $pretty_move;
+ } else {
+ my ($move, $nb) = $pos->{'board'}->prettyprint_move($from_row, $from_col, $to_row, $to_col, $promo);
+ $np->{'last_move'} = $move;
+ }
+ $np->{'last_move_uci'} = Board::move_to_uci_notation($from_row, $from_col, $to_row, $to_col, $promo);
+
+ return bless $np;
+}
+
+# Returns a new Position object, and the parsed UCI move.
+sub make_pretty_move {
+ my ($pos, $move) = @_;
+
+ my ($from_row, $from_col, $to_row, $to_col, $promo) = $pos->parse_pretty_move($move);
+ my $uci_move = Board::move_to_uci_notation($from_row, $from_col, $to_row, $to_col, $promo);
+ $pos = $pos->make_move($from_row, $from_col, $to_row, $to_col, $promo);
+ return ($pos, $uci_move);
+}
+
+sub _pos_to_square {
+ my ($row, $col) = @_;
+ return sprintf("%c%d", ord('a') + $col, 8 - $row);
+}
+
+sub apply_uci_pv {
+ my ($pos, @pv) = @_;
+
+ my $pvpos = $pos;
+ for my $pv_move (@pv) {
+ my ($from_row, $from_col, $to_row, $to_col, $promo) = _parse_uci_move($pv_move);
+ $pvpos = $pvpos->make_move($from_row, $from_col, $to_row, $to_col, $promo);
+ }
+
+ return $pvpos;
+}
+
+sub _col_letter_to_num {
+ return ord(shift) - ord('a');
+}
+
+sub _row_letter_to_num {
+ return 7 - (ord(shift) - ord('1'));
+}
+
+sub _parse_uci_move {
+ my $move = shift;
+ my $from_col = _col_letter_to_num(substr($move, 0, 1));
+ my $from_row = _row_letter_to_num(substr($move, 1, 1));
+ my $to_col = _col_letter_to_num(substr($move, 2, 1));
+ my $to_row = _row_letter_to_num(substr($move, 3, 1));
+ my $promo = substr($move, 4, 1);
+ return ($from_row, $from_col, $to_row, $to_col, $promo);