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fen.c: improve castling for chess960 - chess-puzzles - chess puzzle book genera… |
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git clone git://git.codemadness.org/chess-puzzles |
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--- |
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commit 35cfce88175a31ca9b1db67e70575f66182d8ab2 |
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parent cb828aa3fa341d3af5e9338132497cf49671369f |
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Author: Hiltjo Posthuma <[email protected]> |
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Date: Thu, 21 Dec 2023 22:19:16 +0100 |
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fen.c: improve castling for chess960 |
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In chess960 you can castle right next to the king also. |
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This is handled in the code by "taking a piece", although this is of course |
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your own piece. |
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Note that this doesn't reset the halfmove counter. |
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Diffstat: |
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M fen.c | 86 +++++++++++++++++++++--------… |
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1 file changed, 58 insertions(+), 28 deletions(-) |
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--- |
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diff --git a/fen.c b/fen.c |
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@@ -39,6 +39,20 @@ isvalidsquare(int x, int y) |
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} |
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int |
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+iswhitepiece(int piece) |
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+{ |
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+ return piece == 'K' || piece == 'Q' || piece == 'R' || |
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+ piece == 'B' || piece == 'N' || piece == 'P'; |
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+} |
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+ |
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+int |
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+isblackpiece(int piece) |
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+{ |
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+ return piece == 'k' || piece == 'q' || piece == 'r' || |
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+ piece == 'b' || piece == 'n' || piece == 'p'; |
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+} |
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+ |
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+int |
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isvalidpiece(int c) |
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{ |
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static char pieces[] = "PNBRQKpnbrqk"; |
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@@ -535,33 +549,40 @@ parsemoves(const char *moves) |
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squaretoxy(square, &x, &y); |
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piece = getpiece(x, y); |
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- place(0, x, y); /* clear square */ |
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- |
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- /* place piece at new location */ |
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+ /* target location */ |
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square[0] = *s; |
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square[1] = *(s + 1); |
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squaretoxy(square, &x2, &y2); |
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+ |
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+ /* place piece at new location */ |
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+ place(0, x, y); /* clear previous square */ |
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+ /* take piece (can be your own) */ |
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takepiece = getpiece(x2, y2); |
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- place(piece, x2, y2); |
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+ |
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s += 2; |
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/* if pawn move or taken a piece increase halfmove cou… |
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- if (piece == 'p' || piece == 'P' || takepiece != 0) |
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+ if (piece == 'p' || piece == 'P' || |
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+ (side_to_move == 'w' && isblackpiece(takepiece)) || |
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+ (side_to_move == 'b' && iswhitepiece(takepiece))) |
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halfmove = 0; |
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else |
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halfmove++; |
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/* castling */ |
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if (piece == 'K' && y == 7 && y2 == 7) { |
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- /* white: kingside castling: "e1g1" */ |
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- if (x2 >= x + 2) { /* moved more than 1 square… |
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- place('R', x2 - 1, y2); |
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- x2 = 7; |
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- y2 = 7; |
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- place(0, x2, y2); /* clear rook square… |
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- } else if (x2 <= x - 2) { /* moved more than 1… |
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- /* white: queenside castling: "e1c1" */ |
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- for (i = x2 - 1; i > 0; i--) { |
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+ /* white: kingside castling */ |
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+ if (x2 > x + 1 || takepiece == 'R') { |
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+ for (i = x2; i < 8; i++) { |
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+ if (getpiece(i, y2) == 'R') { |
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+ place(0, i, y2); /* cl… |
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+ place('R', x2 - 1, y2)… |
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+ break; |
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+ } |
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+ } |
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+ } else if (x2 < x - 1 || takepiece == 'R') { |
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+ /* white: queenside castling */ |
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+ for (i = x2; i >= 0; i--) { |
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if (getpiece(i, y2) == 'R') { |
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place('R', x2 + 1, y2)… |
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place(0, i, y2); /* cl… |
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@@ -570,18 +591,24 @@ parsemoves(const char *moves) |
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} |
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} |
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} else if (piece == 'k' && y == 0 && y2 == 0) { |
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- /* black: kingside castling: "e8g8" */ |
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- if (x2 == 6) { |
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- place('r', x2 - 1, y2); |
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- x2 = 7; |
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- y2 = 0; |
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- place(0, x2, y2); /* clear rook square… |
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- } else if (x2 == 2) { |
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- /* black: queenside castling: "e8c8" */ |
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- place('r', x2 + 1, y2); |
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- x2 = 0; |
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- y2 = 0; |
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- place(0, x2, y2); /* clear rook square… |
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+ /* black: kingside castling */ |
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+ if (x2 > x + 1 || takepiece == 'r') { |
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+ for (i = x2; i < 8; i++) { |
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+ if (getpiece(i, y2) == 'r') { |
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+ place(0, i, y2); /* cl… |
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+ place('r', x2 - 1, y2)… |
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+ break; |
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+ } |
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+ } |
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+ } else if (x2 < x - 1 || takepiece == 'R') { |
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+ /* black: queenside castling */ |
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+ for (i = x2; i >= 0; i--) { |
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+ if (getpiece(i, y2) == 'r') { |
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+ place('r', x2 + 1, y2)… |
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+ place(0, i, y2); /* cl… |
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+ break; |
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+ } |
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+ } |
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} |
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} |
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@@ -591,7 +618,7 @@ parsemoves(const char *moves) |
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} else if (piece == 'k') { |
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black_can_castle[0] = black_can_castle[1] = 0; |
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} else if (piece == 'R' && y == 7) { |
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- for (i = 0; i < 7; i++) { |
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+ for (i = 0; i < 8; i++) { |
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if (getpiece(i, y) == 'K') { |
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if (i < x) |
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white_can_castle[0] = … |
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@@ -601,7 +628,7 @@ parsemoves(const char *moves) |
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} |
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} |
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} else if (piece == 'r' && y == 0) { |
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- for (i = 0; i < 7; i++) { |
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+ for (i = 0; i < 8; i++) { |
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if (getpiece(i, y) == 'k') { |
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if (i > x) |
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black_can_castle[1] = … |
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@@ -634,6 +661,9 @@ parsemoves(const char *moves) |
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} |
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} |
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+ /* place piece */ |
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+ place(piece, x2, y2); |
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+ |
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/* possible promotion: queen, knight, bishop */ |
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if (*s == 'q' || *s == 'n' || *s == 'b') { |
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if (side_to_move == 'w') |
