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))
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);
700 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
704 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
717 int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
718 Board xqCheckers, nullBoard;
720 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
721 int rf, int ff, int rt, int ft,
725 GenLegalCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
727 register GenLegalClosure *cl = (GenLegalClosure *) closure;
729 if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
731 if (!(flags & F_IGNORE_CHECK) ) {
732 int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
735 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
736 kings += (board[r][f] == BlackKing);
740 board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
742 check = CheckTest(board, flags, rf, ff, rt, ft,
743 kind == WhiteCapturesEnPassant ||
744 kind == BlackCapturesEnPassant);
745 if(promo) board[rf][ff] = BlackLance;
748 if (flags & F_ATOMIC_CAPTURE) {
749 if (board[rt][ft] != EmptySquare ||
750 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
752 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
753 if (board[rf][ff] == king) return;
754 for (r = rt-1; r <= rt+1; r++) {
755 for (f = ft-1; f <= ft+1; f++) {
756 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
757 board[r][f] == king) return;
762 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
769 int captures; // [HGM] losers
770 } LegalityTestClosure;
773 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
774 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
775 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
776 moves that would destroy your own king. The CASTLE_OK flags are
777 true if castling is not yet ruled out by a move of the king or
778 rook. Return TRUE if the player on move is currently in check and
779 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
781 GenLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
784 int ff, ft, k, left, right, swap;
785 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
786 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
787 int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
791 xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
792 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
793 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
795 if (inCheck) return TRUE;
797 /* Generate castling moves */
798 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
799 wKing = WhiteUnicorn; bKing = BlackUnicorn;
802 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
803 if ((flags & F_WHITE_ON_MOVE) &&
804 (flags & F_WHITE_KCASTLE_OK) &&
805 board[0][ff] == wKing &&
806 board[0][ff + 1] == EmptySquare &&
807 board[0][ff + 2] == EmptySquare &&
808 board[0][BOARD_RGHT-3] == EmptySquare &&
809 board[0][BOARD_RGHT-2] == EmptySquare &&
810 board[0][BOARD_RGHT-1] == WhiteRook &&
811 castlingRights[0] != NoRights && /* [HGM] check rights */
812 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
814 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
815 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
816 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
817 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
819 callback(board, flags,
820 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
821 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
823 if ((flags & F_WHITE_ON_MOVE) &&
824 (flags & F_WHITE_QCASTLE_OK) &&
825 board[0][ff] == wKing &&
826 board[0][ff - 1] == EmptySquare &&
827 board[0][ff - 2] == EmptySquare &&
828 board[0][BOARD_LEFT+2] == EmptySquare &&
829 board[0][BOARD_LEFT+1] == EmptySquare &&
830 board[0][BOARD_LEFT+0] == WhiteRook &&
831 castlingRights[1] != NoRights && /* [HGM] check rights */
832 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
834 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
835 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
836 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
838 callback(board, flags,
839 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
840 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
842 if (!(flags & F_WHITE_ON_MOVE) &&
843 (flags & F_BLACK_KCASTLE_OK) &&
844 board[BOARD_HEIGHT-1][ff] == bKing &&
845 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
846 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
847 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
848 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
849 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
850 castlingRights[3] != NoRights && /* [HGM] check rights */
851 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
853 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
854 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
855 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
856 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
858 callback(board, flags,
859 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
860 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
862 if (!(flags & F_WHITE_ON_MOVE) &&
863 (flags & F_BLACK_QCASTLE_OK) &&
864 board[BOARD_HEIGHT-1][ff] == bKing &&
865 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
866 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
867 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
868 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
869 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
870 castlingRights[4] != NoRights && /* [HGM] check rights */
871 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
873 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
874 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
875 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
877 callback(board, flags,
878 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
879 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
883 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
885 /* generate all potential FRC castling moves (KxR), ignoring flags */
886 /* [HGM] test if the Rooks we find have castling rights */
887 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
890 if ((flags & F_WHITE_ON_MOVE) != 0) {
891 ff = castlingRights[2]; /* King file if we have any rights */
892 if(ff != NoRights && board[0][ff] == WhiteKing) {
893 if (appData.debugMode) {
894 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
895 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
897 ft = castlingRights[0]; /* Rook file if we have H-side rights */
899 right = BOARD_RGHT-2;
900 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
901 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
902 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
903 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
904 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
905 if(ft != NoRights && board[0][ft] == WhiteRook)
906 callback(board, flags, WhiteHSideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
908 ft = castlingRights[1]; /* Rook file if we have A-side rights */
911 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
912 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
913 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
914 if(ff > BOARD_LEFT+2)
915 for(k=left+1; 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, WhiteASideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
921 ff = castlingRights[5]; /* King file if we have any rights */
922 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
923 ft = castlingRights[3]; /* Rook file if we have H-side rights */
925 right = BOARD_RGHT-2;
926 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
927 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
928 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
929 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
930 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
931 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
932 callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
934 ft = castlingRights[4]; /* Rook file if we have A-side rights */
937 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
938 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
939 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
940 if(ff > BOARD_LEFT+2)
941 for(k=left+1; 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, BlackASideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
960 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
961 int rf, int ff, int rt, int ft,
966 CheckTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
968 register CheckTestClosure *cl = (CheckTestClosure *) closure;
970 if (rt == cl->rking && ft == cl->fking) {
971 if(xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
973 xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
978 /* If the player on move were to move from (rf, ff) to (rt, ft), would
979 he leave himself in check? Or if rf == -1, is the player on move
980 in check now? enPassant must be TRUE if the indicated move is an
981 e.p. capture. The possibility of castling out of a check along the
982 back rank is not accounted for (i.e., we still return nonzero), as
983 this is illegal anyway. Return value is the number of times the
986 CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant)
989 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
990 ChessSquare captured = EmptySquare;
991 /* Suppress warnings on uninitialized variables */
993 if(gameInfo.variant == VariantXiangqi)
994 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
995 if(gameInfo.variant == VariantKnightmate)
996 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
1000 captured = board[rf][ft];
1001 board[rf][ft] = EmptySquare;
1003 captured = board[rt][ft];
1005 if(rf == DROP_RANK) board[rt][ft] = ff; else { // [HGM] drop
1006 board[rt][ft] = board[rf][ff];
1007 board[rf][ff] = EmptySquare;
1011 /* For compatibility with ICS wild 9, we scan the board in the
1012 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1013 and we test only whether that one is in check. */
1014 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1015 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1016 if (board[cl.rking][cl.fking] == king) {
1018 if(gameInfo.variant == VariantXiangqi) {
1019 /* [HGM] In Xiangqi opposing Kings means check as well */
1021 dir = (king >= BlackPawn) ? -1 : 1;
1022 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1023 board[i][cl.fking] == EmptySquare; i+=dir );
1024 if(i>=0 && i<BOARD_HEIGHT &&
1025 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1028 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1029 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1030 goto undo_move; /* 2-level break */
1037 if(rf != DROP_RANK) // [HGM] drop
1038 board[rf][ff] = board[rt][ft];
1040 board[rf][ft] = captured;
1041 board[rt][ft] = EmptySquare;
1043 board[rt][ft] = captured;
1047 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1051 LegalDrop (Board board, int flags, ChessSquare piece, int rt, int ft)
1052 { // [HGM] put drop legality testing in separate routine for clarity
1054 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1055 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1056 n = PieceToNumber(piece);
1057 if((gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1058 && gameInfo.variant != VariantBughouse) // in bughouse we don't check for availability, because ICS doesn't always tell us
1059 return ImpossibleMove; // piece not available
1060 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1061 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1062 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1063 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1064 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1065 if(piece == WhitePawn || piece == BlackPawn) {
1067 for(r=1; r<BOARD_HEIGHT-1; r++)
1068 if(board[r][ft] == piece) return IllegalMove; // or there already is a Pawn in file
1069 // should still test if we mate with this Pawn
1071 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1072 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1074 if( (piece == WhitePawn || piece == BlackPawn) &&
1075 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1076 return IllegalMove; /* no pawn drops on 1st/8th */
1078 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1079 if (!(flags & F_IGNORE_CHECK) &&
1080 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1081 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1084 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1085 int rf, int ff, int rt, int ft,
1089 LegalityTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1091 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1093 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1094 cl->captures++; // [HGM] losers: count legal captures
1095 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1100 LegalityTest (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar)
1102 LegalityTestClosure cl; ChessSquare piece, filterPiece;
1104 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1105 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1106 piece = filterPiece = board[rf][ff];
1107 if(PieceToChar(piece) == '~') filterPiece = DEMOTED piece;
1109 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1110 /* (perhaps we should disallow moves that obviously leave us in check?) */
1111 if(piece == WhiteFalcon || piece == BlackFalcon ||
1112 piece == WhiteCobra || piece == BlackCobra)
1113 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1117 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1118 cl.ft = fFilter = ft;
1119 cl.kind = IllegalMove;
1120 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1121 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1122 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1123 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1124 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1125 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1127 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1128 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1129 if(board[rf][ff] < BlackPawn) { // white
1130 if(rf != 0) return IllegalMove; // must be on back rank
1131 if(!(board[VIRGIN][ff] & VIRGIN_W)) return IllegalMove; // non-virgin
1132 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1134 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1135 if(!(board[VIRGIN][ff] & VIRGIN_B)) return IllegalMove; // non-virgin
1136 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1139 if(gameInfo.variant == VariantShogi) {
1140 /* [HGM] Shogi promotions. '=' means defer */
1141 if(rf != DROP_RANK && cl.kind == NormalMove) {
1142 ChessSquare piece = board[rf][ff];
1144 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1145 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1146 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1147 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1148 promoChar = '+'; // allowed ICS notations
1149 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1150 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1151 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1152 else if(flags & F_WHITE_ON_MOVE) {
1153 if( (int) piece < (int) WhiteWazir &&
1154 (rf >= BOARD_HEIGHT - BOARD_HEIGHT/3 || rt >= BOARD_HEIGHT - BOARD_HEIGHT/3) ) {
1155 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1156 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1157 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1158 else /* promotion optional, default is defer */
1159 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1160 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1162 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1163 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1164 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1165 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1166 else /* promotion optional, default is defer */
1167 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1168 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1172 if (promoChar != NULLCHAR) {
1173 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1174 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1175 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1176 if(piece == EmptySquare)
1177 cl.kind = ImpossibleMove; // non-existing piece
1178 if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1179 if(promoChar != PieceToChar(BlackKing)) {
1180 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1181 if(piece == BlackLance) cl.kind = ImpossibleMove;
1182 } else { // promotion to King allowed only if we do not haave two yet
1183 int r, f, kings = 0;
1184 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1185 if(kings == 2) cl.kind = IllegalMove;
1187 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1188 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1189 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1190 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1191 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1192 cl.kind = IllegalMove; // promotion to King usually not allowed
1194 cl.kind = IllegalMove;
1204 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1205 int rf, int ff, int rt, int ft,
1209 MateTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1211 register MateTestClosure *cl = (MateTestClosure *) closure;
1216 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1218 MateTest (Board board, int flags)
1221 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1222 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1224 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1225 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1226 nrKing += (board[r][f] == king); // stm has king
1227 if( board[r][f] != EmptySquare ) {
1228 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1233 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1234 case VariantShatranj:
1235 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1239 if(nrKing == 0) return MT_NOKING;
1242 if(myPieces == 1) return MT_BARE;
1245 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1246 // [HGM] 3check: yet to do!
1248 return inCheck ? MT_CHECK : MT_NONE;
1250 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1251 && gameInfo.variant != VariantSChess && gameInfo.variant != VariantGrand) { // drop game
1252 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1253 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1254 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1255 if(board[n][holdings] != EmptySquare) {
1256 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1257 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
1260 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1261 return myPieces == hisPieces ? MT_STALEMATE :
1262 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1263 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1264 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1266 return inCheck ? MT_CHECKMATE
1267 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj || gameInfo.variant == VariantShogi) ?
1268 MT_STAINMATE : MT_STALEMATE;
1273 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1274 int rf, int ff, int rt, int ft,
1278 DisambiguateCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1280 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1281 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1283 // [HGM] wild: for wild-card pieces rt and rf are dummies
1284 if(piece == WhiteFalcon || piece == BlackFalcon ||
1285 piece == WhiteCobra || piece == BlackCobra)
1288 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1289 || PieceToChar(board[rf][ff]) == '~'
1290 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1292 (cl->rfIn == -1 || cl->rfIn == rf) &&
1293 (cl->ffIn == -1 || cl->ffIn == ff) &&
1294 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1295 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1298 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1299 // [HGM] oneclick: if multiple moves, be sure we remember capture
1300 cl->piece = board[rf][ff];
1303 cl->rt = wildCard ? cl->rtIn : rt;
1304 cl->ft = wildCard ? cl->ftIn : ft;
1307 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
1312 Disambiguate (Board board, int flags, DisambiguateClosure *closure)
1314 int illegal = 0; char c = closure->promoCharIn;
1316 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1317 closure->count = closure->captures = 0;
1318 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1319 closure->kind = ImpossibleMove;
1320 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
1321 fFilter = closure->ftIn;
1322 if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
1323 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1324 if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
1325 closure->count = closure->captures = 0;
1326 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1327 closure->kind = ImpossibleMove;
1328 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
1331 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
1332 if (closure->count == 0) {
1333 /* See if it's an illegal move due to check */
1335 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1336 if (closure->count == 0) {
1337 /* No, it's not even that */
1338 if(!appData.testLegality && closure->pieceIn != EmptySquare) {
1339 int f, r; // if there is only a single piece of the requested type on the board, use that
1340 closure->rt = closure->rtIn, closure->ft = closure->ftIn;
1341 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1342 if(board[r][f] == closure->pieceIn) closure->count++, closure->rf = r, closure->ff = f;
1343 if(closure->count > 1) illegal = 0; // ambiguous
1345 if(closure->count == 0) {
1346 if (appData.debugMode) { int i, j;
1347 for(i=BOARD_HEIGHT-1; i>=0; i--) {
1348 for(j=0; j<BOARD_WIDTH; j++)
1349 fprintf(debugFP, "%3d", (int) board[i][j]);
1350 fprintf(debugFP, "\n");
1358 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
1359 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
1360 if(closure->piece < BlackPawn) { // white
1361 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
1362 if(!(board[VIRGIN][closure->ff] & VIRGIN_W)) closure->kind = IllegalMove; // non-virgin
1363 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
1365 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
1366 if(!(board[VIRGIN][closure->ff] & VIRGIN_B)) closure->kind = IllegalMove; // non-virgin
1367 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
1370 if(gameInfo.variant == VariantShogi) {
1371 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
1372 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
1373 ChessSquare piece = closure->piece;
1374 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1375 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1376 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1377 c = '+'; // allowed ICS notations
1378 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
1379 else if(flags & F_WHITE_ON_MOVE) {
1380 if( (int) piece < (int) WhiteWazir &&
1381 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
1382 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
1383 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
1384 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
1385 else /* promotion optional, default is defer */
1386 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
1387 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1389 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
1390 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
1391 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
1392 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
1393 else /* promotion optional, default is defer */
1394 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
1395 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1398 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
1399 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
1401 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
1402 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
1403 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
1404 gameInfo.variant == VariantMakruk || gameInfo.variant == VariantASEAN)
1405 c = PieceToChar(BlackFerz);
1406 else if(gameInfo.variant == VariantGreat)
1407 c = PieceToChar(BlackMan);
1408 else if(gameInfo.variant == VariantGrand)
1409 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
1411 c = PieceToChar(BlackQueen);
1412 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
1413 } else if (c != NULLCHAR) closure->kind = IllegalMove;
1415 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
1416 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
1417 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
1418 if (closure->count > 1) {
1419 closure->kind = AmbiguousMove;
1422 /* Note: If more than one illegal move matches, but no legal
1423 moves, we return IllegalMove, not AmbiguousMove. Caller
1424 can look at closure->count to detect this.
1426 closure->kind = IllegalMove;
1440 } CoordsToAlgebraicClosure;
1442 extern void CoordsToAlgebraicCallback P((Board board, int flags,
1443 ChessMove kind, int rf, int ff,
1444 int rt, int ft, VOIDSTAR closure));
1447 CoordsToAlgebraicCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1449 register CoordsToAlgebraicClosure *cl =
1450 (CoordsToAlgebraicClosure *) closure;
1452 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
1453 (board[rf][ff] == cl->piece
1454 || PieceToChar(board[rf][ff]) == '~' &&
1455 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
1459 cl->kind = kind; /* this is the move we want */
1461 cl->file++; /* need file to rule out this move */
1465 cl->rank++; /* need rank to rule out this move */
1467 cl->either++; /* rank or file will rule out this move */
1473 /* Convert coordinates to normal algebraic notation.
1474 promoChar must be NULLCHAR or 'x' if not a promotion.
1477 CoordsToAlgebraic (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar, char out[MOVE_LEN])
1481 char *outp = out, c;
1482 CoordsToAlgebraicClosure cl;
1484 if (rf == DROP_RANK) {
1485 if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
1486 /* Bughouse piece drop */
1487 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
1492 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1494 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
1497 if (promoChar == 'x') promoChar = NULLCHAR;
1498 piece = board[rf][ff];
1499 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
1504 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1505 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1506 /* Keep short notation if move is illegal only because it
1507 leaves the player in check, but still return IllegalMove */
1508 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
1509 if (kind == IllegalMove) break;
1514 if (ff == ft && board[rt][ft] == EmptySquare) { /* [HGM] Xiangqi has straight noncapts! */
1515 /* Non-capture; use style "e5" */
1518 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1520 /* Capture; use style "exd5" */
1521 if(gameInfo.variant != VariantXiangqi || board[rt][ft] != EmptySquare )
1522 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
1526 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1528 /* Use promotion suffix style "=Q" */
1530 if (promoChar != NULLCHAR) {
1531 if(gameInfo.variant == VariantShogi) {
1532 /* [HGM] ... but not in Shogi! */
1533 *outp++ = promoChar == '=' ? '=' : '+';
1536 *outp++ = ToUpper(promoChar);
1545 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
1546 /* Code added by Tord: FRC castling. */
1547 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
1548 (piece == BlackKing && board[rt][ft] == BlackRook)) {
1550 safeStrCpy(out, "O-O", MOVE_LEN);
1552 safeStrCpy(out, "O-O-O", MOVE_LEN);
1553 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1555 /* End of code added by Tord */
1556 /* Test for castling or ICS wild castling */
1557 /* Use style "O-O" (oh-oh) for PGN compatibility */
1558 else if (rf == rt &&
1559 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
1560 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
1561 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
1562 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
1563 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
1564 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1566 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1568 /* This notation is always unambiguous, unless there are
1569 kings on both the d and e files, with "wild castling"
1570 possible for the king on the d file and normal castling
1571 possible for the other. ICS rules for wild 9
1572 effectively make castling illegal for either king in
1573 this situation. So I am not going to worry about it;
1574 I'll just generate an ambiguous O-O in this case.
1576 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1579 /* else fall through */
1584 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1585 cl.ft = fFilter = ft;
1587 cl.kind = IllegalMove;
1588 cl.rank = cl.file = cl.either = 0;
1589 c = PieceToChar(piece) ;
1590 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece)); // [HGM] speed
1592 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1593 /* Generate pretty moves for moving into check, but
1594 still return IllegalMove.
1596 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece));
1597 if (cl.kind == IllegalMove) break;
1598 cl.kind = IllegalMove;
1601 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
1602 else "Ngf3" or "Ngxf7",
1603 else "N1f3" or "N5xf7",
1604 else "Ng1f3" or "Ng5xf7".
1606 if( c == '~' || c == '+') {
1607 /* [HGM] print nonexistent piece as its demoted version */
1608 piece = (ChessSquare) (DEMOTED piece);
1610 if(c=='+') *outp++ = c;
1611 *outp++ = ToUpper(PieceToChar(piece));
1613 if (cl.file || (cl.either && !cl.rank)) {
1619 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1622 if(board[rt][ft] != EmptySquare)
1628 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1629 if (gameInfo.variant == VariantShogi) {
1630 /* [HGM] in Shogi non-pawns can promote */
1631 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
1633 else if (gameInfo.variant != VariantSuper && promoChar &&
1634 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
1636 *outp++ = ToUpper(promoChar);
1638 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
1640 *outp++ = ToUpper(promoChar);
1646 /* Moving a nonexistent piece */
1650 /* Not a legal move, even ignoring check.
1651 If there was a piece on the from square,
1652 use style "Ng1g3" or "Ng1xe8";
1653 if there was a pawn or nothing (!),
1654 use style "g1g3" or "g1xe8". Use "x"
1655 if a piece was on the to square, even
1656 a piece of the same color.
1660 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
1662 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
1663 c += (board[r][f] == piece); // count on-board pieces of given type
1664 *outp++ = ToUpper(PieceToChar(piece));
1666 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
1670 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1672 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
1676 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1677 /* Use promotion suffix style "=Q" */
1678 if (promoChar != NULLCHAR && promoChar != 'x') {
1680 *outp++ = ToUpper(promoChar);
1687 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
1696 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
1698 int preyStackPointer, chaseStackPointer;
1701 unsigned char rf, ff, rt, ft;
1705 unsigned char rank, file;
1711 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
1713 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
1714 int rf, int ff, int rt, int ft,
1718 AttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1719 { // For adding captures that can lead to chase indictment to the chaseStack
1720 if(board[rt][ft] == EmptySquare) return; // non-capture
1721 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
1722 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
1723 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
1724 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
1725 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
1726 chaseStack[chaseStackPointer].rf = rf;
1727 chaseStack[chaseStackPointer].ff = ff;
1728 chaseStack[chaseStackPointer].rt = rt;
1729 chaseStack[chaseStackPointer].ft = ft;
1730 chaseStackPointer++;
1733 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
1734 int rf, int ff, int rt, int ft,
1738 ExistingAttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1739 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
1741 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
1743 if(board[rt][ft] == EmptySquare) return; // no capture
1744 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
1745 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
1747 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
1748 for(i=0; i<chaseStackPointer; i++) {
1749 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
1750 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
1751 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
1752 chaseStack[i] = chaseStack[--chaseStackPointer];
1758 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
1759 int rf, int ff, int rt, int ft,
1763 ProtectedCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1764 { // for determining if a piece (given through the closure) is protected
1765 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
1767 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
1768 if(appData.debugMode && board[rt][ft] != EmptySquare)
1769 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
1772 extern char moveList[MAX_MOVES][MOVE_LEN];
1775 PerpetualChase (int first, int last)
1776 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
1779 ChessSquare captured;
1781 preyStackPointer = 0; // clear stack of chased pieces
1782 for(i=first; i<last; i+=2) { // for all positions with same side to move
1783 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
1784 chaseStackPointer = 0; // clear stack that is going to hold possible chases
1785 // determine all captures possible after the move, and put them on chaseStack
1786 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
1787 if(appData.debugMode) { int n;
1788 for(n=0; n<chaseStackPointer; n++)
1789 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1790 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1791 fprintf(debugFP, ": all capts\n");
1793 // determine all captures possible before the move, and delete them from chaseStack
1794 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
1795 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
1796 cl.rt = moveList[i][3]-ONE;
1797 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
1798 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
1799 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
1800 xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
1801 if(appData.debugMode) { int n;
1802 for(n=0; n<chaseStackPointer; n++)
1803 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1804 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1805 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
1807 // chaseSack now contains all captures made possible by the move
1808 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
1809 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1810 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1812 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
1813 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
1815 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
1816 continue; // C or H attack on R is always chase; leave on chaseStack
1818 if(attacker == victim) {
1819 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
1820 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
1821 // we can capture back with equal piece, so this is no chase but a sacrifice
1822 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
1823 j--; /* ! */ continue;
1828 // the attack is on a lower piece, or on a pinned or blocked equal one
1829 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
1830 CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
1831 // test if the victim is protected by a true protector. First make the capture.
1832 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1833 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1834 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
1835 // Then test if the opponent can recapture
1836 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
1837 cl.rt = chaseStack[j].rt;
1838 cl.ft = chaseStack[j].ft;
1839 if(appData.debugMode) {
1840 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
1842 xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
1843 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
1844 xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
1845 // unmake the capture
1846 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1847 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
1848 // if a recapture was found, piece is protected, and we are not chasing it.
1849 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
1850 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
1854 // chaseStack now contains all moves that chased
1855 if(appData.debugMode) { int n;
1856 for(n=0; n<chaseStackPointer; n++)
1857 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1858 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1859 fprintf(debugFP, ": chases\n");
1861 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
1862 for(j=0; j<chaseStackPointer; j++) {
1863 preyStack[j].rank = chaseStack[j].rt;
1864 preyStack[j].file = chaseStack[j].ft;
1866 preyStackPointer = chaseStackPointer;
1869 for(j=0; j<chaseStackPointer; j++) {
1870 for(k=0; k<preyStackPointer; k++) {
1871 // search the victim of each chase move on the preyStack (first occurrence)
1872 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
1873 if(k < tail) break; // piece was already identified as still being chased
1874 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
1875 preyStack[tail] = preyStack[k]; // by swapping
1876 preyStack[k] = preyStack[preyStackPointer];
1882 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
1883 if(appData.debugMode) { int n;
1884 for(n=0; n<preyStackPointer; n++)
1885 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
1886 fprintf(debugFP, "always chased upto ply %d\n", i);
1888 // now adjust the location of the chased pieces according to opponent move
1889 for(j=0; j<preyStackPointer; j++) {
1890 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
1891 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
1892 preyStack[j].rank = moveList[i+1][3]-ONE;
1893 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
1898 return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
1899 : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the