fen.c: simplify castling code - chess-puzzles - chess puzzle book generator
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---
(DIR) commit 14096028aee533f132200b020687e1ce3884105b
(DIR) parent 3ccf4d4450965cc2853d9cbc8b81b75cfd44660a
(HTM) Author: Hiltjo Posthuma <hiltjo@codemadness.org>
Date: Mon, 22 Jan 2024 01:04:59 +0100
fen.c: simplify castling code
Diffstat:
M TODO | 2 --
M fen.c | 56 ++++++++++---------------------
2 files changed, 18 insertions(+), 40 deletions(-)
---
(DIR) diff --git a/TODO b/TODO
@@ -8,8 +8,6 @@
- in check, checkmate.
- test more chess960 black kingside and queenside castling.
- test more long sequence and halfmove and movenumber counts.
-- code cleanup:
- - castling code can be much simplified.
? PGN output: add game termination state?
- PGN output: add stalemate?
- PGN output: but what if resign, time-out, draw offer?
(DIR) diff --git a/fen.c b/fen.c
@@ -1088,7 +1088,8 @@ board_playmoves(struct board *b, const char *moves)
{
char square[3];
const char *castled, *s;
- int firstmove, i, x, y, x2, y2, side, otherside, piece, takepiece, tookpiece;
+ int firstmove, i, x, y, x2, y2, side, otherside, piece;
+ int rookpiece, takepiece, tookpiece;
int countfile, countrank, countboard, px, py;
int promote, tookeps;
@@ -1171,59 +1172,38 @@ board_playmoves(struct board *b, const char *moves)
castled = NULL;
/* castling */
- if (piece == 'K' && y == 7 && y2 == 7) {
- /* white: kingside castling */
- if (x2 > x + 1 || (x2 > x && takepiece == 'R')) {
- for (i = x2; i < 8; i++) {
- if (getpiece(b, i, y2) == 'R') {
- place(b, 0, x, y); /* clear previous square */
- place(b, 0, i, y2); /* clear rook square */
- place(b, 'R', x2 - 1, y2); /* rook next to king */
- castled = "O-O";
- break;
- }
- }
- } else if (x2 < x - 1 || (x2 < x && takepiece == 'R')) {
- /* white: queenside castling */
- for (i = x2; i >= 0; i--) {
- if (getpiece(b, i, y2) == 'R') {
- place(b, 0, x, y); /* clear previous square */
- place(b, 0, i, y2); /* clear rook square */
- place(b, 'R', x2 + 1, y2); /* rook next to king */
- castled = "O-O-O";
- break;
- }
- }
- }
- } else if (piece == 'k' && y == 0 && y2 == 0) {
- /* black: kingside castling */
- if (x2 > x + 1 || (x2 > x && takepiece == 'r')) {
+ if ((piece == 'K' && y == 7 && y2 == 7) ||
+ (piece == 'k' && y == 0 && y2 == 0)) {
+ rookpiece = piece == 'K' ? 'R' : 'r';
+
+ /* kingside castling */
+ if (x2 > x + 1 || (x2 > x && takepiece == rookpiece)) {
for (i = x2; i < 8; i++) {
- if (getpiece(b, i, y2) == 'r') {
+ if (getpiece(b, i, y2) == rookpiece) {
place(b, 0, x, y); /* clear previous square */
place(b, 0, i, y2); /* clear rook square */
- place(b, 'r', x2 - 1, y2); /* rook next to king */
+ place(b, rookpiece, x2 - 1, y2); /* rook next to king */
+ place(b, piece, x2, y2); /* place king */
+ x2 = i; /* set square for highlight */
castled = "O-O";
break;
}
}
- } else if (x2 < x - 1 || (x2 < x && takepiece == 'r')) {
- /* black: queenside castling */
+ } else if (x2 < x - 1 || (x2 < x && takepiece == rookpiece)) {
+ /* queenside castling */
for (i = x2; i >= 0; i--) {
- if (getpiece(b, i, y2) == 'r') {
+ if (getpiece(b, i, y2) == rookpiece) {
place(b, 0, x, y); /* clear previous square */
place(b, 0, i, y2); /* clear rook square */
- place(b, 'r', x2 + 1, y2); /* rook next to king */
+ place(b, rookpiece, x2 + 1, y2); /* rook next to king */
+ place(b, piece, x2, y2); /* place king */
+ x2 = i; /* set square for highlight */
castled = "O-O-O";
break;
}
}
}
}
- if (castled) {
- place(b, piece, x2, y2); /* place king */
- x2 = i; /* set square for highlight */
- }
/* remove the ability to castle */
if (piece == 'K') {