2 * moves.c - Move generation and checking
4 * Copyright 1991 by Digital Equipment Corporation, Maynard,
7 * Enhancements Copyright 1992-2001, 2002, 2003, 2004, 2005, 2006,
8 * 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
10 * Enhancements Copyright 2005 Alessandro Scotti
12 * The following terms apply to Digital Equipment Corporation's copyright
14 * ------------------------------------------------------------------------
17 * Permission to use, copy, modify, and distribute this software and its
18 * documentation for any purpose and without fee is hereby granted,
19 * provided that the above copyright notice appear in all copies and that
20 * both that copyright notice and this permission notice appear in
21 * supporting documentation, and that the name of Digital not be
22 * used in advertising or publicity pertaining to distribution of the
23 * software without specific, written prior permission.
25 * DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
26 * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
27 * DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
28 * ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
29 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
30 * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
32 * ------------------------------------------------------------------------
34 * The following terms apply to the enhanced version of XBoard
35 * distributed by the Free Software Foundation:
36 * ------------------------------------------------------------------------
38 * GNU XBoard is free software: you can redistribute it and/or modify
39 * it under the terms of the GNU General Public License as published by
40 * the Free Software Foundation, either version 3 of the License, or (at
41 * your option) any later version.
43 * GNU XBoard is distributed in the hope that it will be useful, but
44 * WITHOUT ANY WARRANTY; without even the implied warranty of
45 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
46 * General Public License for more details.
48 * You should have received a copy of the GNU General Public License
49 * along with this program. If not, see http://www.gnu.org/licenses/. *
51 *------------------------------------------------------------------------
52 ** See the file ChangeLog for a revision history. */
59 #else /* not HAVE_STRING_H */
61 #endif /* not HAVE_STRING_H */
67 int WhitePiece P((ChessSquare));
68 int BlackPiece P((ChessSquare));
69 int SameColor P((ChessSquare, ChessSquare));
70 int PosFlags(int index);
72 extern signed char initialRights[BOARD_FILES]; /* [HGM] all rights enabled, set in InitPosition */
76 WhitePiece (ChessSquare piece)
78 return (int) piece >= (int) WhitePawn && (int) piece < (int) BlackPawn;
82 BlackPiece (ChessSquare piece)
84 return (int) piece >= (int) BlackPawn && (int) piece < (int) EmptySquare;
89 SameColor (ChessSquare piece1, ChessSquare piece2)
91 return ((int) piece1 >= (int) WhitePawn && /* [HGM] can be > King ! */
92 (int) piece1 < (int) BlackPawn &&
93 (int) piece2 >= (int) WhitePawn &&
94 (int) piece2 < (int) BlackPawn)
95 || ((int) piece1 >= (int) BlackPawn &&
96 (int) piece1 < (int) EmptySquare &&
97 (int) piece2 >= (int) BlackPawn &&
98 (int) piece2 < (int) EmptySquare);
101 #define SameColor(piece1, piece2) (piece1 < EmptySquare && piece2 < EmptySquare && (piece1 < BlackPawn) == (piece2 < BlackPawn) || piece1 == DarkSquare || piece2 == DarkSquare)
104 char pieceToChar[] = {
105 'P', 'N', 'B', 'R', 'Q', 'F', 'E', 'A', 'C', 'W', 'M',
106 'O', 'H', 'I', 'J', 'G', 'D', 'V', 'L', 'S', 'U', 'K',
107 'p', 'n', 'b', 'r', 'q', 'f', 'e', 'a', 'c', 'w', 'm',
108 'o', 'h', 'i', 'j', 'g', 'd', 'v', 'l', 's', 'u', 'k',
110 char pieceNickName[EmptySquare];
113 PieceToChar (ChessSquare p)
115 if((int)p < 0 || (int)p >= (int)EmptySquare) return('x'); /* [HGM] for safety */
116 return pieceToChar[(int) p];
120 PieceToNumber (ChessSquare p) /* [HGM] holdings: count piece type, ignoring non-participating piece types */
123 ChessSquare start = (int)p >= (int)BlackPawn ? BlackPawn : WhitePawn;
125 while(start++ != p) if(pieceToChar[(int)start-1] != '.') i++;
133 if(c == '.') return EmptySquare;
134 for(i=0; i< (int) EmptySquare; i++)
135 if(pieceNickName[i] == c) return (ChessSquare) i;
136 for(i=0; i< (int) EmptySquare; i++)
137 if(pieceToChar[i] == c) return (ChessSquare) i;
142 CopyBoard (Board to, Board from)
146 for (i = 0; i < BOARD_HEIGHT; i++)
147 for (j = 0; j < BOARD_WIDTH; j++)
148 to[i][j] = from[i][j];
149 for (j = 0; j < BOARD_FILES; j++) // [HGM] gamestate: copy castling rights and ep status
150 to[VIRGIN][j] = from[VIRGIN][j],
151 to[CASTLING][j] = from[CASTLING][j];
152 to[HOLDINGS_SET] = 0; // flag used in ICS play
156 CompareBoards (Board board1, Board board2)
160 for (i = 0; i < BOARD_HEIGHT; i++)
161 for (j = 0; j < BOARD_WIDTH; j++) {
162 if (board1[i][j] != board2[i][j])
169 /* Call callback once for each pseudo-legal move in the given
170 position, except castling moves. A move is pseudo-legal if it is
171 legal, or if it would be legal except that it leaves the king in
172 check. In the arguments, epfile is EP_NONE if the previous move
173 was not a double pawn push, or the file 0..7 if it was, or
174 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
175 Promotion moves generated are to Queen only.
178 GenPseudoLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
179 // speed: only do moves with this piece type
182 int i, j, d, s, fs, rs, rt, ft, m;
183 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
184 int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand ? 3 : 1;
186 for (rf = 0; rf < BOARD_HEIGHT; rf++)
187 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
191 if(board[rf][ff] == EmptySquare) continue;
192 if ((flags & F_WHITE_ON_MOVE) != (board[rf][ff] < BlackPawn)) continue; // [HGM] speed: wrong color
194 m = 0; piece = board[rf][ff];
195 if(PieceToChar(piece) == '~')
196 piece = (ChessSquare) ( DEMOTED piece );
197 if(filter != EmptySquare && piece != filter) continue;
198 if(gameInfo.variant == VariantShogi)
199 piece = (ChessSquare) ( SHOGI piece );
201 switch ((int)piece) {
202 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
204 /* can't happen ([HGM] except for faries...) */
208 if(gameInfo.variant == VariantXiangqi) {
209 /* [HGM] capture and move straight ahead in Xiangqi */
210 if (rf < BOARD_HEIGHT-1 &&
211 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
212 callback(board, flags, NormalMove,
213 rf, ff, rf + 1, ff, closure);
215 /* and move sideways when across the river */
216 for (s = -1; s <= 1; s += 2) {
217 if (rf >= BOARD_HEIGHT>>1 &&
218 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
219 !WhitePiece(board[rf][ff+s]) ) {
220 callback(board, flags, NormalMove,
221 rf, ff, rf, ff+s, closure);
226 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
227 callback(board, flags,
228 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
229 rf, ff, rf + 1, ff, closure);
231 if (rf <= (BOARD_HEIGHT>>1)-3 && board[rf+1][ff] == EmptySquare && // [HGM] grand: also on 3rd rank on 10-board
232 gameInfo.variant != VariantShatranj && /* [HGM] */
233 gameInfo.variant != VariantCourier && /* [HGM] */
234 board[rf+2][ff] == EmptySquare ) {
235 callback(board, flags, NormalMove,
236 rf, ff, rf+2, ff, closure);
238 for (s = -1; s <= 1; s += 2) {
239 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
240 ((flags & F_KRIEGSPIEL_CAPTURE) ||
241 BlackPiece(board[rf + 1][ff + s]))) {
242 callback(board, flags,
243 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
244 rf, ff, rf + 1, ff + s, closure);
246 if (rf >= BOARD_HEIGHT+1>>1) {// [HGM] grand: 4th & 5th rank on 10-board
247 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
248 (epfile == ff + s || epfile == EP_UNKNOWN) && rf < BOARD_HEIGHT-3 &&
249 board[rf][ff + s] == BlackPawn &&
250 board[rf+1][ff + s] == EmptySquare) {
251 callback(board, flags, WhiteCapturesEnPassant,
252 rf, ff, rf+1, ff + s, closure);
259 if(gameInfo.variant == VariantXiangqi) {
260 /* [HGM] capture straight ahead in Xiangqi */
261 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
262 callback(board, flags, NormalMove,
263 rf, ff, rf - 1, ff, closure);
265 /* and move sideways when across the river */
266 for (s = -1; s <= 1; s += 2) {
267 if (rf < BOARD_HEIGHT>>1 &&
268 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
269 !BlackPiece(board[rf][ff+s]) ) {
270 callback(board, flags, NormalMove,
271 rf, ff, rf, ff+s, closure);
276 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
277 callback(board, flags,
278 rf <= promoRank ? BlackPromotion : NormalMove,
279 rf, ff, rf - 1, ff, closure);
281 if (rf >= (BOARD_HEIGHT+1>>1)+2 && board[rf-1][ff] == EmptySquare && // [HGM] grand
282 gameInfo.variant != VariantShatranj && /* [HGM] */
283 gameInfo.variant != VariantCourier && /* [HGM] */
284 board[rf-2][ff] == EmptySquare) {
285 callback(board, flags, NormalMove,
286 rf, ff, rf-2, ff, closure);
288 for (s = -1; s <= 1; s += 2) {
289 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
290 ((flags & F_KRIEGSPIEL_CAPTURE) ||
291 WhitePiece(board[rf - 1][ff + s]))) {
292 callback(board, flags,
293 rf <= promoRank ? BlackPromotion : NormalMove,
294 rf, ff, rf - 1, ff + s, closure);
296 if (rf < BOARD_HEIGHT>>1) {
297 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
298 (epfile == ff + s || epfile == EP_UNKNOWN) && rf > 2 &&
299 board[rf][ff + s] == WhitePawn &&
300 board[rf-1][ff + s] == EmptySquare) {
301 callback(board, flags, BlackCapturesEnPassant,
302 rf, ff, rf-1, ff + s, closure);
313 for (i = -1; i <= 1; i += 2)
314 for (j = -1; j <= 1; j += 2)
315 for (s = 1; s <= 2; s++) {
318 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
319 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
320 && !SameColor(board[rf][ff], board[rt][ft]))
321 callback(board, flags, NormalMove,
322 rf, ff, rt, ft, closure);
326 case SHOGI WhiteKnight:
327 for (s = -1; s <= 1; s += 2) {
328 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
329 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
330 callback(board, flags, NormalMove,
331 rf, ff, rf + 2, ff + s, closure);
336 case SHOGI BlackKnight:
337 for (s = -1; s <= 1; s += 2) {
338 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
339 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
340 callback(board, flags, NormalMove,
341 rf, ff, rf - 2, ff + s, closure);
348 for (d = 0; d <= 1; d++)
349 for (s = -1; s <= 1; s += 2) {
352 rt = rf + (i * s) * d;
353 ft = ff + (i * s) * (1 - d);
354 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
355 if (m == 0 && board[rt][ft] == EmptySquare)
356 callback(board, flags, NormalMove,
357 rf, ff, rt, ft, closure);
358 if (m == 1 && board[rt][ft] != EmptySquare &&
359 !SameColor(board[rf][ff], board[rt][ft]) )
360 callback(board, flags, NormalMove,
361 rf, ff, rt, ft, closure);
362 if (board[rt][ft] != EmptySquare && m++) break;
367 /* Gold General (and all its promoted versions) . First do the */
368 /* diagonal forward steps, then proceed as normal Wazir */
369 case SHOGI WhiteWazir:
370 case SHOGI (PROMOTED WhitePawn):
371 case SHOGI (PROMOTED WhiteKnight):
372 case SHOGI (PROMOTED WhiteQueen):
373 case SHOGI (PROMOTED WhiteFerz):
374 for (s = -1; s <= 1; s += 2) {
375 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
376 !SameColor(board[rf][ff], board[rf + 1][ff + s])) {
377 callback(board, flags, NormalMove,
378 rf, ff, rf + 1, ff + s, closure);
383 case SHOGI BlackWazir:
384 case SHOGI (PROMOTED BlackPawn):
385 case SHOGI (PROMOTED BlackKnight):
386 case SHOGI (PROMOTED BlackQueen):
387 case SHOGI (PROMOTED BlackFerz):
388 for (s = -1; s <= 1; s += 2) {
389 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
390 !SameColor(board[rf][ff], board[rf - 1][ff + s])) {
391 callback(board, flags, NormalMove,
392 rf, ff, rf - 1, ff + s, closure);
399 for (d = 0; d <= 1; d++)
400 for (s = -1; s <= 1; s += 2) {
402 ft = ff + s * (1 - d);
403 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
404 && !SameColor(board[rf][ff], board[rt][ft]) &&
405 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
406 callback(board, flags, NormalMove,
407 rf, ff, rt, ft, closure);
413 /* [HGM] support Shatranj pieces */
414 for (rs = -1; rs <= 1; rs += 2)
415 for (fs = -1; fs <= 1; fs += 2) {
418 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
419 && ( gameInfo.variant != VariantXiangqi ||
420 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
422 && !SameColor(board[rf][ff], board[rt][ft]))
423 callback(board, flags, NormalMove,
424 rf, ff, rt, ft, closure);
425 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier
426 || gameInfo.variant == VariantXiangqi) continue; // classical Alfil
427 rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
429 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
430 && !SameColor(board[rf][ff], board[rt][ft]))
431 callback(board, flags, NormalMove,
432 rf, ff, rt, ft, closure);
434 if(gameInfo.variant == VariantSpartan)
435 for(fs = -1; fs <= 1; fs += 2) {
437 if (!(ft < BOARD_LEFT || ft >= BOARD_RGHT) && board[rf][ft] == EmptySquare)
438 callback(board, flags, NormalMove, rf, ff, rf, ft, closure);
442 /* Make Dragon-Horse also do Dababba moves outside Shogi, for better disambiguation in variant Fairy */
445 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
446 for (s = -2; s <= 2; s += 4) {
448 ft = ff + s * (1 - d);
449 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
450 if (SameColor(board[rf][ff], board[rt][ft])) continue;
451 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
454 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
455 case SHOGI WhiteCardinal:
456 case SHOGI BlackCardinal:
459 /* Capablanca Archbishop continues as Knight */
464 /* Shogi Bishops are ordinary Bishops */
465 case SHOGI WhiteBishop:
466 case SHOGI BlackBishop:
469 for (rs = -1; rs <= 1; rs += 2)
470 for (fs = -1; fs <= 1; fs += 2)
474 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
475 if (SameColor(board[rf][ff], board[rt][ft])) break;
476 callback(board, flags, NormalMove,
477 rf, ff, rt, ft, closure);
478 if (board[rt][ft] != EmptySquare) break;
480 if(m==1) goto mounted;
481 if(m==2) goto finishGold;
482 /* Bishop falls through */
485 /* Shogi Lance is unlike anything, and asymmetric at that */
486 case SHOGI WhiteQueen:
490 if (rt >= BOARD_HEIGHT) break;
491 if (SameColor(board[rf][ff], board[rt][ft])) break;
492 callback(board, flags, NormalMove,
493 rf, ff, rt, ft, closure);
494 if (board[rt][ft] != EmptySquare) break;
498 case SHOGI BlackQueen:
503 if (SameColor(board[rf][ff], board[rt][ft])) break;
504 callback(board, flags, NormalMove,
505 rf, ff, rt, ft, closure);
506 if (board[rt][ft] != EmptySquare) break;
510 /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
513 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
514 for (s = -2; s <= 2; s += 4) {
516 ft = ff + s * (1 - d);
517 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT || board[rf+rt>>1][ff+ft>>1] == EmptySquare) continue;
518 if (SameColor(board[rf][ff], board[rt][ft])) continue;
519 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
521 if(gameInfo.variant == VariantSpartan) rookRange = 2; // in Spartan Chess restrict range to modern Dababba
524 /* Shogi Dragon King has to continue as Ferz after Rook moves */
525 case SHOGI WhiteDragon:
526 case SHOGI BlackDragon:
529 /* Capablanca Chancellor sets flag to continue as Knight */
533 m += (gameInfo.variant == VariantSpartan); // in Spartan Chess Chancellor is used for Dragon King.
535 /* Shogi Rooks are ordinary Rooks */
536 case SHOGI WhiteRook:
537 case SHOGI BlackRook:
541 for (d = 0; d <= 1; d++)
542 for (s = -1; s <= 1; s += 2)
544 rt = rf + (i * s) * d;
545 ft = ff + (i * s) * (1 - d);
546 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
547 if (SameColor(board[rf][ff], board[rt][ft])) break;
548 callback(board, flags, NormalMove,
549 rf, ff, rt, ft, closure);
550 if (board[rt][ft] != EmptySquare || i == rookRange) break;
552 if(m==1) goto mounted;
553 if(m==2) goto finishSilver;
558 for (rs = -1; rs <= 1; rs++)
559 for (fs = -1; fs <= 1; fs++) {
560 if (rs == 0 && fs == 0) continue;
564 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
565 if (SameColor(board[rf][ff], board[rt][ft])) break;
566 callback(board, flags, NormalMove,
567 rf, ff, rt, ft, closure);
568 if (board[rt][ft] != EmptySquare) break;
573 /* Shogi Pawn and Silver General: first the Pawn move, */
574 /* then the General continues like a Ferz */
576 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
577 case SHOGI WhitePawn:
578 case SHOGI WhiteFerz:
579 if (rf < BOARD_HEIGHT-1 &&
580 !SameColor(board[rf][ff], board[rf + 1][ff]) )
581 callback(board, flags, NormalMove,
582 rf, ff, rf + 1, ff, closure);
583 if(piece != SHOGI WhitePawn) goto finishSilver;
587 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
588 case SHOGI BlackPawn:
589 case SHOGI BlackFerz:
591 !SameColor(board[rf][ff], board[rf - 1][ff]) )
592 callback(board, flags, NormalMove,
593 rf, ff, rf - 1, ff, closure);
594 if(piece == SHOGI BlackPawn) break;
599 /* [HGM] support Shatranj pieces */
600 for (rs = -1; rs <= 1; rs += 2)
601 for (fs = -1; fs <= 1; fs += 2) {
604 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
605 if (!SameColor(board[rf][ff], board[rt][ft]) &&
606 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
607 callback(board, flags, NormalMove,
608 rf, ff, rt, ft, closure);
614 m++; // [HGM] superchess: use for Centaur
616 case SHOGI WhiteKing:
617 case SHOGI BlackKing:
621 for (i = -1; i <= 1; i++)
622 for (j = -1; j <= 1; j++) {
623 if (i == 0 && j == 0) continue;
626 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
627 if (SameColor(board[rf][ff], board[rt][ft])) continue;
628 callback(board, flags, NormalMove,
629 rf, ff, rt, ft, closure);
631 if(m==1) goto mounted;
634 case WhiteNightrider:
635 case BlackNightrider:
636 for (i = -1; i <= 1; i += 2)
637 for (j = -1; j <= 1; j += 2)
638 for (s = 1; s <= 2; s++) { int k;
642 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
643 if (SameColor(board[rf][ff], board[rt][ft])) break;
644 callback(board, flags, NormalMove,
645 rf, ff, rt, ft, closure);
646 if (board[rt][ft] != EmptySquare) break;
652 /* First do Bishop,then continue like Chancellor */
653 for (rs = -1; rs <= 1; rs += 2)
654 for (fs = -1; fs <= 1; fs += 2)
658 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
659 if (SameColor(board[rf][ff], board[rt][ft])) break;
660 callback(board, flags, NormalMove,
661 rf, ff, rt, ft, closure);
662 if (board[rt][ft] != EmptySquare) break;
667 // Use Lance as Berolina / Spartan Pawn.
669 if(gameInfo.variant == VariantSuper) goto Amazon;
670 if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
671 callback(board, flags,
672 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
673 rf, ff, rf + 1, ff, closure);
674 for (s = -1; s <= 1; s += 2) {
675 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
676 callback(board, flags,
677 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
678 rf, ff, rf + 1, ff + s, closure);
679 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
680 callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
685 if(gameInfo.variant == VariantSuper) goto Amazon;
686 if (rf > 0 && WhitePiece(board[rf - 1][ff]))
687 callback(board, flags,
688 rf <= promoRank ? BlackPromotion : NormalMove,
689 rf, ff, rf - 1, ff, closure);
690 for (s = -1; s <= 1; s += 2) {
691 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
692 callback(board, flags,
693 rf <= promoRank ? BlackPromotion : NormalMove,
694 rf, ff, rf - 1, ff + s, closure);
695 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
696 callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
702 for(rt = rf - 2; rt <= rf + 2; rt++) for(ft = ff - 2; ft <= ff + 2; ft++) {
703 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
704 if (!(ff == ft && rf == rt) && SameColor(board[rf][ff], board[rt][ft])) continue;
705 callback(board, flags, (rt-rf)*(rt-rf) + (ff-ft)*(ff-ft) < 3 && board[rt][ft] != EmptySquare ? FirstLeg : NormalMove,
706 rf, ff, rt, ft, closure);
710 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
714 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
727 int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
728 Board xqCheckers, nullBoard;
730 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
731 int rf, int ff, int rt, int ft,
735 GenLegalCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
737 register GenLegalClosure *cl = (GenLegalClosure *) closure;
739 if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
741 if (board[EP_STATUS] == EP_IRON_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)) return; //[HGM] lion
743 if (!(flags & F_IGNORE_CHECK) ) {
744 int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
747 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
748 kings += (board[r][f] == BlackKing);
752 board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
754 check = CheckTest(board, flags, rf, ff, rt, ft,
755 kind == WhiteCapturesEnPassant ||
756 kind == BlackCapturesEnPassant);
757 if(promo) board[rf][ff] = BlackLance;
760 if (flags & F_ATOMIC_CAPTURE) {
761 if (board[rt][ft] != EmptySquare ||
762 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
764 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
765 if (board[rf][ff] == king) return;
766 for (r = rt-1; r <= rt+1; r++) {
767 for (f = ft-1; f <= ft+1; f++) {
768 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
769 board[r][f] == king) return;
774 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
781 int captures; // [HGM] losers
782 } LegalityTestClosure;
785 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
786 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
787 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
788 moves that would destroy your own king. The CASTLE_OK flags are
789 true if castling is not yet ruled out by a move of the king or
790 rook. Return TRUE if the player on move is currently in check and
791 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
793 GenLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
796 int ff, ft, k, left, right, swap;
797 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
798 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
799 int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
803 xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
804 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
805 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
807 if (inCheck) return TRUE;
809 /* Generate castling moves */
810 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
811 wKing = WhiteUnicorn; bKing = BlackUnicorn;
814 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
815 if ((flags & F_WHITE_ON_MOVE) &&
816 (flags & F_WHITE_KCASTLE_OK) &&
817 board[0][ff] == wKing &&
818 board[0][ff + 1] == EmptySquare &&
819 board[0][ff + 2] == EmptySquare &&
820 board[0][BOARD_RGHT-3] == EmptySquare &&
821 board[0][BOARD_RGHT-2] == EmptySquare &&
822 board[0][BOARD_RGHT-1] == WhiteRook &&
823 castlingRights[0] != NoRights && /* [HGM] check rights */
824 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
826 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
827 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
828 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
829 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
831 callback(board, flags,
832 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
833 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
835 if ((flags & F_WHITE_ON_MOVE) &&
836 (flags & F_WHITE_QCASTLE_OK) &&
837 board[0][ff] == wKing &&
838 board[0][ff - 1] == EmptySquare &&
839 board[0][ff - 2] == EmptySquare &&
840 board[0][BOARD_LEFT+2] == EmptySquare &&
841 board[0][BOARD_LEFT+1] == EmptySquare &&
842 board[0][BOARD_LEFT+0] == WhiteRook &&
843 castlingRights[1] != NoRights && /* [HGM] check rights */
844 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
846 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
847 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
848 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
850 callback(board, flags,
851 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
852 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
854 if (!(flags & F_WHITE_ON_MOVE) &&
855 (flags & F_BLACK_KCASTLE_OK) &&
856 board[BOARD_HEIGHT-1][ff] == bKing &&
857 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
858 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
859 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
860 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
861 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
862 castlingRights[3] != NoRights && /* [HGM] check rights */
863 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
865 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
866 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
867 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
868 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
870 callback(board, flags,
871 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
872 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
874 if (!(flags & F_WHITE_ON_MOVE) &&
875 (flags & F_BLACK_QCASTLE_OK) &&
876 board[BOARD_HEIGHT-1][ff] == bKing &&
877 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
878 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
879 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
880 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
881 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
882 castlingRights[4] != NoRights && /* [HGM] check rights */
883 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
885 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
886 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
887 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
889 callback(board, flags,
890 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
891 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
895 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
897 /* generate all potential FRC castling moves (KxR), ignoring flags */
898 /* [HGM] test if the Rooks we find have castling rights */
899 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
902 if ((flags & F_WHITE_ON_MOVE) != 0) {
903 ff = castlingRights[2]; /* King file if we have any rights */
904 if(ff != NoRights && board[0][ff] == WhiteKing) {
905 if (appData.debugMode) {
906 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
907 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
909 ft = castlingRights[0]; /* Rook file if we have H-side rights */
911 right = BOARD_RGHT-2;
912 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
913 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
914 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
915 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
916 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
917 if(ft != NoRights && board[0][ft] == WhiteRook)
918 callback(board, flags, WhiteHSideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
920 ft = castlingRights[1]; /* Rook file if we have A-side rights */
923 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
924 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
925 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
926 if(ff > BOARD_LEFT+2)
927 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
928 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
929 if(ft != NoRights && board[0][ft] == WhiteRook)
930 callback(board, flags, WhiteASideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
933 ff = castlingRights[5]; /* King file if we have any rights */
934 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
935 ft = castlingRights[3]; /* Rook file if we have H-side rights */
937 right = BOARD_RGHT-2;
938 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
939 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
940 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
941 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
942 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
943 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
944 callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
946 ft = castlingRights[4]; /* Rook file if we have A-side rights */
949 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
950 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
951 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
952 if(ff > BOARD_LEFT+2)
953 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
954 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
955 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
956 callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
972 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
973 int rf, int ff, int rt, int ft,
978 CheckTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
980 register CheckTestClosure *cl = (CheckTestClosure *) closure;
982 if (rt == cl->rking && ft == cl->fking) {
983 if(xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
985 xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
987 if( board[EP_STATUS] == EP_ROYAL_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)
988 && (gameInfo.variant != VariantLion || board[rf][ff] != WhiteKing && board[rf][ff] != BlackKing) )
989 cl->check++; // [HGM] lion: forbidden counterstrike against Lion equated to putting yourself in check
993 /* If the player on move were to move from (rf, ff) to (rt, ft), would
994 he leave himself in check? Or if rf == -1, is the player on move
995 in check now? enPassant must be TRUE if the indicated move is an
996 e.p. capture. The possibility of castling out of a check along the
997 back rank is not accounted for (i.e., we still return nonzero), as
998 this is illegal anyway. Return value is the number of times the
1001 CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant)
1003 CheckTestClosure cl;
1004 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1005 ChessSquare captured = EmptySquare, ep;
1006 /* Suppress warnings on uninitialized variables */
1008 if(gameInfo.variant == VariantXiangqi)
1009 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
1010 if(gameInfo.variant == VariantKnightmate)
1011 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
1015 captured = board[rf][ft];
1016 board[rf][ft] = EmptySquare;
1018 captured = board[rt][ft];
1020 if(rf == DROP_RANK) board[rt][ft] = ff; else { // [HGM] drop
1021 board[rt][ft] = board[rf][ff];
1022 board[rf][ff] = EmptySquare;
1024 ep = board[EP_STATUS];
1025 if( captured == WhiteLion || captured == BlackLion ) { // [HGM] lion: Chu Lion-capture rules
1026 ChessSquare victim = killX < 0 ? EmptySquare : board[killY][killX];
1027 if( (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion) && // capturer is Lion
1028 (ff - ft > 1 || ft - ff > 1 || rf - rt > 1 || rt - rf > 1) && // captures from a distance
1029 (victim == EmptySquare || victim == WhitePawn || victim == BlackPawn) ) // no or worthless 'bridge'
1030 board[EP_STATUS] = EP_ROYAL_LION; // on distant Lion x Lion victim must not be pseudo-legally protected
1034 /* For compatibility with ICS wild 9, we scan the board in the
1035 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1036 and we test only whether that one is in check. */
1037 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1038 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1039 if (board[cl.rking][cl.fking] == king) {
1041 if(gameInfo.variant == VariantXiangqi) {
1042 /* [HGM] In Xiangqi opposing Kings means check as well */
1044 dir = (king >= BlackPawn) ? -1 : 1;
1045 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1046 board[i][cl.fking] == EmptySquare; i+=dir );
1047 if(i>=0 && i<BOARD_HEIGHT &&
1048 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1051 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1052 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1053 goto undo_move; /* 2-level break */
1060 if(rf != DROP_RANK) // [HGM] drop
1061 board[rf][ff] = board[rt][ft];
1063 board[rf][ft] = captured;
1064 board[rt][ft] = EmptySquare;
1066 board[rt][ft] = captured;
1068 board[EP_STATUS] = ep;
1071 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1075 LegalDrop (Board board, int flags, ChessSquare piece, int rt, int ft)
1076 { // [HGM] put drop legality testing in separate routine for clarity
1078 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1079 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1080 n = PieceToNumber(piece);
1081 if((gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1082 && gameInfo.variant != VariantBughouse) // in bughouse we don't check for availability, because ICS doesn't always tell us
1083 return ImpossibleMove; // piece not available
1084 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1085 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1086 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1087 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1088 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1089 if(piece == WhitePawn || piece == BlackPawn) {
1091 for(r=1; r<BOARD_HEIGHT-1; r++)
1092 if(board[r][ft] == piece) return IllegalMove; // or there already is a Pawn in file
1093 // should still test if we mate with this Pawn
1095 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1096 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1098 if( (piece == WhitePawn || piece == BlackPawn) &&
1099 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1100 return IllegalMove; /* no pawn drops on 1st/8th */
1102 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1103 if (!(flags & F_IGNORE_CHECK) &&
1104 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1105 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1108 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1109 int rf, int ff, int rt, int ft,
1113 LegalityTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1115 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1117 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1118 cl->captures++; // [HGM] losers: count legal captures
1119 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1124 LegalityTest (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar)
1126 LegalityTestClosure cl; ChessSquare piece, filterPiece;
1128 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1129 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1130 piece = filterPiece = board[rf][ff];
1131 if(PieceToChar(piece) == '~') filterPiece = DEMOTED piece;
1133 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1134 /* (perhaps we should disallow moves that obviously leave us in check?) */
1135 if(piece == WhiteFalcon || piece == BlackFalcon ||
1136 piece == WhiteCobra || piece == BlackCobra)
1137 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1141 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1142 cl.ft = fFilter = ft;
1143 cl.kind = IllegalMove;
1144 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1145 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1146 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1147 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1148 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1149 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1151 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1152 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1153 if(board[rf][ff] < BlackPawn) { // white
1154 if(rf != 0) return IllegalMove; // must be on back rank
1155 if(!(board[VIRGIN][ff] & VIRGIN_W)) return IllegalMove; // non-virgin
1156 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1158 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1159 if(!(board[VIRGIN][ff] & VIRGIN_B)) return IllegalMove; // non-virgin
1160 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1163 if(gameInfo.variant == VariantChu) {
1164 if(cl.kind != NormalMove || promoChar == NULLCHAR || promoChar == '=') return cl.kind;
1165 if(promoChar != '+')
1166 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1167 if(PieceToChar(CHUPROMOTED board[rf][ff]) != '+') return ImpossibleMove;
1168 return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1170 if(gameInfo.variant == VariantShogi) {
1171 /* [HGM] Shogi promotions. '=' means defer */
1172 if(rf != DROP_RANK && cl.kind == NormalMove) {
1173 ChessSquare piece = board[rf][ff];
1175 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1176 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1177 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1178 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1179 promoChar = '+'; // allowed ICS notations
1180 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1181 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1182 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1183 else if(flags & F_WHITE_ON_MOVE) {
1184 if( (int) piece < (int) WhiteWazir &&
1185 (rf >= BOARD_HEIGHT - BOARD_HEIGHT/3 || rt >= BOARD_HEIGHT - BOARD_HEIGHT/3) ) {
1186 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1187 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1188 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1189 else /* promotion optional, default is defer */
1190 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1191 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1193 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1194 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1195 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1196 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1197 else /* promotion optional, default is defer */
1198 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1199 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1203 if (promoChar != NULLCHAR) {
1204 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1205 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1206 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1207 if(piece == EmptySquare)
1208 cl.kind = ImpossibleMove; // non-existing piece
1209 if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1210 if(promoChar != PieceToChar(BlackKing)) {
1211 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1212 if(piece == BlackLance) cl.kind = ImpossibleMove;
1213 } else { // promotion to King allowed only if we do not haave two yet
1214 int r, f, kings = 0;
1215 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1216 if(kings == 2) cl.kind = IllegalMove;
1218 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1219 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1220 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1221 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1222 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1223 cl.kind = IllegalMove; // promotion to King usually not allowed
1225 cl.kind = IllegalMove;
1235 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1236 int rf, int ff, int rt, int ft,
1240 MateTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1242 register MateTestClosure *cl = (MateTestClosure *) closure;
1247 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1249 MateTest (Board board, int flags)
1252 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1253 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1255 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1256 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1257 nrKing += (board[r][f] == king); // stm has king
1258 if( board[r][f] != EmptySquare ) {
1259 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1264 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1265 case VariantShatranj:
1266 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1270 if(nrKing == 0) return MT_NOKING;
1273 if(myPieces == 1) return MT_BARE;
1276 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1277 // [HGM] 3check: yet to do!
1279 return inCheck ? MT_CHECK : MT_NONE;
1281 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1282 && gameInfo.variant != VariantSChess && gameInfo.variant != VariantGrand) { // drop game
1283 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1284 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1285 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1286 if(board[n][holdings] != EmptySquare) {
1287 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1288 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
1291 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1292 return myPieces == hisPieces ? MT_STALEMATE :
1293 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1294 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1295 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1297 return inCheck ? MT_CHECKMATE
1298 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj || gameInfo.variant == VariantShogi) ?
1299 MT_STAINMATE : MT_STALEMATE;
1304 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1305 int rf, int ff, int rt, int ft,
1309 DisambiguateCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1311 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1312 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1314 // [HGM] wild: for wild-card pieces rt and rf are dummies
1315 if(piece == WhiteFalcon || piece == BlackFalcon ||
1316 piece == WhiteCobra || piece == BlackCobra)
1319 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1320 || PieceToChar(board[rf][ff]) == '~'
1321 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1323 (cl->rfIn == -1 || cl->rfIn == rf) &&
1324 (cl->ffIn == -1 || cl->ffIn == ff) &&
1325 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1326 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1329 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1330 // [HGM] oneclick: if multiple moves, be sure we remember capture
1331 cl->piece = board[rf][ff];
1334 cl->rt = wildCard ? cl->rtIn : rt;
1335 cl->ft = wildCard ? cl->ftIn : ft;
1338 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
1343 Disambiguate (Board board, int flags, DisambiguateClosure *closure)
1345 int illegal = 0; char c = closure->promoCharIn;
1347 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1348 closure->count = closure->captures = 0;
1349 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1350 closure->kind = ImpossibleMove;
1351 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
1352 fFilter = closure->ftIn;
1353 if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
1354 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1355 if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
1356 closure->count = closure->captures = 0;
1357 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1358 closure->kind = ImpossibleMove;
1359 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
1362 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
1363 if (closure->count == 0) {
1364 /* See if it's an illegal move due to check */
1366 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1367 if (closure->count == 0) {
1368 /* No, it's not even that */
1369 if(!appData.testLegality && closure->pieceIn != EmptySquare) {
1370 int f, r; // if there is only a single piece of the requested type on the board, use that
1371 closure->rt = closure->rtIn, closure->ft = closure->ftIn;
1372 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1373 if(board[r][f] == closure->pieceIn) closure->count++, closure->rf = r, closure->ff = f;
1374 if(closure->count > 1) illegal = 0; // ambiguous
1376 if(closure->count == 0) {
1377 if (appData.debugMode) { int i, j;
1378 for(i=BOARD_HEIGHT-1; i>=0; i--) {
1379 for(j=0; j<BOARD_WIDTH; j++)
1380 fprintf(debugFP, "%3d", (int) board[i][j]);
1381 fprintf(debugFP, "\n");
1389 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
1390 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
1391 if(closure->piece < BlackPawn) { // white
1392 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
1393 if(!(board[VIRGIN][closure->ff] & VIRGIN_W)) closure->kind = IllegalMove; // non-virgin
1394 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
1396 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
1397 if(!(board[VIRGIN][closure->ff] & VIRGIN_B)) closure->kind = IllegalMove; // non-virgin
1398 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
1401 if(gameInfo.variant == VariantChu) {
1402 if(c == '+') closure->kind = (flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion); // for now, accept any
1404 if(gameInfo.variant == VariantShogi) {
1405 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
1406 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
1407 ChessSquare piece = closure->piece;
1408 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1409 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1410 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1411 c = '+'; // allowed ICS notations
1412 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
1413 else if(flags & F_WHITE_ON_MOVE) {
1414 if( (int) piece < (int) WhiteWazir &&
1415 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
1416 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
1417 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
1418 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
1419 else /* promotion optional, default is defer */
1420 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
1421 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1423 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
1424 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
1425 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
1426 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
1427 else /* promotion optional, default is defer */
1428 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
1429 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1432 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
1433 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
1435 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
1436 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
1437 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
1438 gameInfo.variant == VariantMakruk || gameInfo.variant == VariantASEAN)
1439 c = PieceToChar(BlackFerz);
1440 else if(gameInfo.variant == VariantGreat)
1441 c = PieceToChar(BlackMan);
1442 else if(gameInfo.variant == VariantGrand)
1443 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
1445 c = PieceToChar(BlackQueen);
1446 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
1447 } else if (c != NULLCHAR) closure->kind = IllegalMove;
1449 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
1450 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
1451 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
1452 if (closure->count > 1) {
1453 closure->kind = AmbiguousMove;
1456 /* Note: If more than one illegal move matches, but no legal
1457 moves, we return IllegalMove, not AmbiguousMove. Caller
1458 can look at closure->count to detect this.
1460 closure->kind = IllegalMove;
1474 } CoordsToAlgebraicClosure;
1476 extern void CoordsToAlgebraicCallback P((Board board, int flags,
1477 ChessMove kind, int rf, int ff,
1478 int rt, int ft, VOIDSTAR closure));
1481 CoordsToAlgebraicCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1483 register CoordsToAlgebraicClosure *cl =
1484 (CoordsToAlgebraicClosure *) closure;
1486 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
1487 (board[rf][ff] == cl->piece
1488 || PieceToChar(board[rf][ff]) == '~' &&
1489 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
1493 cl->kind = kind; /* this is the move we want */
1495 cl->file++; /* need file to rule out this move */
1499 cl->rank++; /* need rank to rule out this move */
1501 cl->either++; /* rank or file will rule out this move */
1507 /* Convert coordinates to normal algebraic notation.
1508 promoChar must be NULLCHAR or 'x' if not a promotion.
1511 CoordsToAlgebraic (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar, char out[MOVE_LEN])
1515 char *outp = out, c;
1516 CoordsToAlgebraicClosure cl;
1518 if (rf == DROP_RANK) {
1519 if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
1520 /* Bughouse piece drop */
1521 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
1526 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1528 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
1531 if (promoChar == 'x') promoChar = NULLCHAR;
1532 piece = board[rf][ff];
1533 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
1538 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1539 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1540 /* Keep short notation if move is illegal only because it
1541 leaves the player in check, but still return IllegalMove */
1542 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
1543 if (kind == IllegalMove) break;
1548 if (ff == ft && board[rt][ft] == EmptySquare) { /* [HGM] Xiangqi has straight noncapts! */
1549 /* Non-capture; use style "e5" */
1552 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1554 /* Capture; use style "exd5" */
1555 if(gameInfo.variant != VariantXiangqi || board[rt][ft] != EmptySquare )
1556 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
1560 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1562 /* Use promotion suffix style "=Q" */
1564 if (promoChar != NULLCHAR) {
1565 if(IS_SHOGI(gameInfo.variant)) {
1566 /* [HGM] ... but not in Shogi! */
1567 *outp++ = promoChar == '=' ? '=' : '+';
1570 *outp++ = ToUpper(promoChar);
1579 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
1580 /* Code added by Tord: FRC castling. */
1581 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
1582 (piece == BlackKing && board[rt][ft] == BlackRook)) {
1584 safeStrCpy(out, "O-O", MOVE_LEN);
1586 safeStrCpy(out, "O-O-O", MOVE_LEN);
1587 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1589 /* End of code added by Tord */
1590 /* Test for castling or ICS wild castling */
1591 /* Use style "O-O" (oh-oh) for PGN compatibility */
1592 else if (rf == rt &&
1593 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
1594 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
1595 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
1596 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
1597 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
1598 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1600 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1602 /* This notation is always unambiguous, unless there are
1603 kings on both the d and e files, with "wild castling"
1604 possible for the king on the d file and normal castling
1605 possible for the other. ICS rules for wild 9
1606 effectively make castling illegal for either king in
1607 this situation. So I am not going to worry about it;
1608 I'll just generate an ambiguous O-O in this case.
1610 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1613 /* else fall through */
1618 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1619 cl.ft = fFilter = ft;
1621 cl.kind = IllegalMove;
1622 cl.rank = cl.file = cl.either = 0;
1623 c = PieceToChar(piece) ;
1624 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece)); // [HGM] speed
1626 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1627 /* Generate pretty moves for moving into check, but
1628 still return IllegalMove.
1630 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece));
1631 if (cl.kind == IllegalMove) break;
1632 cl.kind = IllegalMove;
1635 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
1636 else "Ngf3" or "Ngxf7",
1637 else "N1f3" or "N5xf7",
1638 else "Ng1f3" or "Ng5xf7".
1640 if( c == '~' || c == '+') {
1641 /* [HGM] print nonexistent piece as its demoted version */
1642 piece = (ChessSquare) (DEMOTED piece);
1644 if(c=='+') *outp++ = c;
1645 *outp++ = ToUpper(PieceToChar(piece));
1647 if (cl.file || (cl.either && !cl.rank)) {
1653 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1656 if(board[rt][ft] != EmptySquare)
1662 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1663 if (IS_SHOGI(gameInfo.variant)) {
1664 /* [HGM] in Shogi non-pawns can promote */
1665 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
1667 else if (gameInfo.variant != VariantSuper && promoChar &&
1668 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
1670 *outp++ = ToUpper(promoChar);
1672 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
1674 *outp++ = ToUpper(promoChar);
1680 /* Moving a nonexistent piece */
1684 /* Not a legal move, even ignoring check.
1685 If there was a piece on the from square,
1686 use style "Ng1g3" or "Ng1xe8";
1687 if there was a pawn or nothing (!),
1688 use style "g1g3" or "g1xe8". Use "x"
1689 if a piece was on the to square, even
1690 a piece of the same color.
1694 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
1696 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
1697 c += (board[r][f] == piece); // count on-board pieces of given type
1698 *outp++ = ToUpper(PieceToChar(piece));
1700 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
1704 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1706 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
1710 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1711 /* Use promotion suffix style "=Q" */
1712 if (promoChar != NULLCHAR && promoChar != 'x') {
1714 *outp++ = ToUpper(promoChar);
1721 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
1730 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
1732 int preyStackPointer, chaseStackPointer;
1735 unsigned char rf, ff, rt, ft;
1739 unsigned char rank, file;
1745 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
1747 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
1748 int rf, int ff, int rt, int ft,
1752 AttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1753 { // For adding captures that can lead to chase indictment to the chaseStack
1754 if(board[rt][ft] == EmptySquare) return; // non-capture
1755 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
1756 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
1757 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
1758 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
1759 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
1760 chaseStack[chaseStackPointer].rf = rf;
1761 chaseStack[chaseStackPointer].ff = ff;
1762 chaseStack[chaseStackPointer].rt = rt;
1763 chaseStack[chaseStackPointer].ft = ft;
1764 chaseStackPointer++;
1767 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
1768 int rf, int ff, int rt, int ft,
1772 ExistingAttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1773 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
1775 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
1777 if(board[rt][ft] == EmptySquare) return; // no capture
1778 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
1779 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
1781 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
1782 for(i=0; i<chaseStackPointer; i++) {
1783 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
1784 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
1785 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
1786 chaseStack[i] = chaseStack[--chaseStackPointer];
1792 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
1793 int rf, int ff, int rt, int ft,
1797 ProtectedCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1798 { // for determining if a piece (given through the closure) is protected
1799 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
1801 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
1802 if(appData.debugMode && board[rt][ft] != EmptySquare)
1803 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
1806 extern char moveList[MAX_MOVES][MOVE_LEN];
1809 PerpetualChase (int first, int last)
1810 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
1813 ChessSquare captured;
1815 preyStackPointer = 0; // clear stack of chased pieces
1816 for(i=first; i<last; i+=2) { // for all positions with same side to move
1817 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
1818 chaseStackPointer = 0; // clear stack that is going to hold possible chases
1819 // determine all captures possible after the move, and put them on chaseStack
1820 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
1821 if(appData.debugMode) { int n;
1822 for(n=0; n<chaseStackPointer; n++)
1823 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1824 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1825 fprintf(debugFP, ": all capts\n");
1827 // determine all captures possible before the move, and delete them from chaseStack
1828 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
1829 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
1830 cl.rt = moveList[i][3]-ONE;
1831 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
1832 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
1833 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
1834 xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
1835 if(appData.debugMode) { int n;
1836 for(n=0; n<chaseStackPointer; n++)
1837 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1838 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1839 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
1841 // chaseSack now contains all captures made possible by the move
1842 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
1843 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1844 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1846 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
1847 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
1849 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
1850 continue; // C or H attack on R is always chase; leave on chaseStack
1852 if(attacker == victim) {
1853 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
1854 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
1855 // we can capture back with equal piece, so this is no chase but a sacrifice
1856 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
1857 j--; /* ! */ continue;
1862 // the attack is on a lower piece, or on a pinned or blocked equal one
1863 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
1864 CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
1865 // test if the victim is protected by a true protector. First make the capture.
1866 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1867 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1868 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
1869 // Then test if the opponent can recapture
1870 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
1871 cl.rt = chaseStack[j].rt;
1872 cl.ft = chaseStack[j].ft;
1873 if(appData.debugMode) {
1874 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
1876 xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
1877 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
1878 xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
1879 // unmake the capture
1880 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1881 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
1882 // if a recapture was found, piece is protected, and we are not chasing it.
1883 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
1884 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
1888 // chaseStack now contains all moves that chased
1889 if(appData.debugMode) { int n;
1890 for(n=0; n<chaseStackPointer; n++)
1891 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1892 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1893 fprintf(debugFP, ": chases\n");
1895 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
1896 for(j=0; j<chaseStackPointer; j++) {
1897 preyStack[j].rank = chaseStack[j].rt;
1898 preyStack[j].file = chaseStack[j].ft;
1900 preyStackPointer = chaseStackPointer;
1903 for(j=0; j<chaseStackPointer; j++) {
1904 for(k=0; k<preyStackPointer; k++) {
1905 // search the victim of each chase move on the preyStack (first occurrence)
1906 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
1907 if(k < tail) break; // piece was already identified as still being chased
1908 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
1909 preyStack[tail] = preyStack[k]; // by swapping
1910 preyStack[k] = preyStack[preyStackPointer];
1916 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
1917 if(appData.debugMode) { int n;
1918 for(n=0; n<preyStackPointer; n++)
1919 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
1920 fprintf(debugFP, "always chased upto ply %d\n", i);
1922 // now adjust the location of the chased pieces according to opponent move
1923 for(j=0; j<preyStackPointer; j++) {
1924 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
1925 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
1926 preyStack[j].rank = moveList[i+1][3]-ONE;
1927 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
1932 return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
1933 : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the