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 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_SIZE]; /* [HGM] all rights enabled, set in InitPosition */
78 return (int) piece >= (int) WhitePawn && (int) piece < (int) BlackPawn;
84 return (int) piece >= (int) BlackPawn && (int) piece < (int) EmptySquare;
87 int SameColor(piece1, piece2)
88 ChessSquare piece1, piece2;
90 return ((int) piece1 >= (int) WhitePawn && /* [HGM] can be > King ! */
91 (int) piece1 < (int) BlackPawn &&
92 (int) piece2 >= (int) WhitePawn &&
93 (int) piece2 < (int) BlackPawn)
94 || ((int) piece1 >= (int) BlackPawn &&
95 (int) piece1 < (int) EmptySquare &&
96 (int) piece2 >= (int) BlackPawn &&
97 (int) piece2 < (int) EmptySquare);
100 ChessSquare PromoPiece(moveType)
106 case WhitePromotionQueen:
108 case BlackPromotionQueen:
110 case WhitePromotionRook:
112 case BlackPromotionRook:
114 case WhitePromotionBishop:
116 case BlackPromotionBishop:
118 case WhitePromotionKnight:
120 case BlackPromotionKnight:
122 case WhitePromotionKing:
124 case BlackPromotionKing:
126 case WhitePromotionChancellor:
127 return WhiteMarshall;
128 case BlackPromotionChancellor:
129 return BlackMarshall;
130 case WhitePromotionArchbishop:
132 case BlackPromotionArchbishop:
134 case WhitePromotionCentaur:
136 case BlackPromotionCentaur:
141 char pieceToChar[] = {
142 'P', 'N', 'B', 'R', 'Q', 'F', 'E', 'A', 'C', 'W', 'M',
143 'O', 'H', 'I', 'J', 'G', 'D', 'V', 'L', 'S', 'U', 'K',
144 'p', 'n', 'b', 'r', 'q', 'f', 'e', 'a', 'c', 'w', 'm',
145 'o', 'h', 'i', 'j', 'g', 'd', 'v', 'l', 's', 'u', 'k',
151 if((int)p < 0 || (int)p >= (int)EmptySquare) return('x'); /* [HGM] for safety */
152 return pieceToChar[(int) p];
155 int PieceToNumber(p) /* [HGM] holdings: count piece type, ignoring non-participating piece types */
159 ChessSquare start = (int)p >= (int)BlackPawn ? BlackPawn : WhitePawn;
161 while(start++ != p) if(pieceToChar[(int)start-1] != '.') i++;
165 ChessSquare CharToPiece(c)
169 for(i=0; i< (int) EmptySquare; i++)
170 if(pieceToChar[i] == c) return (ChessSquare) i;
174 ChessMove PromoCharToMoveType(whiteOnMove, promoChar)
177 { /* [HGM] made dependent on CharToPiece to alow alternate piece letters */
178 ChessSquare piece = CharToPiece(whiteOnMove ? ToUpper(promoChar) : ToLower(promoChar) );
181 if(promoChar == NULLCHAR) return NormalMove;
185 return WhitePromotionQueen;
187 return WhitePromotionRook;
189 return WhitePromotionBishop;
191 return WhitePromotionKnight;
193 return WhitePromotionKing;
195 return WhitePromotionArchbishop;
197 return WhitePromotionChancellor;
199 return WhitePromotionCentaur;
201 return BlackPromotionQueen;
203 return BlackPromotionRook;
205 return BlackPromotionBishop;
207 return BlackPromotionKnight;
209 return BlackPromotionKing;
211 return BlackPromotionArchbishop;
213 return BlackPromotionChancellor;
215 return BlackPromotionCentaur;
217 // not all promotion implemented yet! Take Queen for those we don't know.
218 return (whiteOnMove ? WhitePromotionQueen : BlackPromotionQueen);
222 void CopyBoard(to, from)
227 for (i = 0; i < BOARD_HEIGHT; i++)
228 for (j = 0; j < BOARD_WIDTH; j++)
229 to[i][j] = from[i][j];
232 int CompareBoards(board1, board2)
233 Board board1, board2;
237 for (i = 0; i < BOARD_HEIGHT; i++)
238 for (j = 0; j < BOARD_WIDTH; j++) {
239 if (board1[i][j] != board2[i][j])
246 /* Call callback once for each pseudo-legal move in the given
247 position, except castling moves. A move is pseudo-legal if it is
248 legal, or if it would be legal except that it leaves the king in
249 check. In the arguments, epfile is EP_NONE if the previous move
250 was not a double pawn push, or the file 0..7 if it was, or
251 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
252 Promotion moves generated are to Queen only.
254 void GenPseudoLegal(board, flags, epfile, callback, closure)
258 MoveCallback callback;
262 int i, j, d, s, fs, rs, rt, ft, m;
264 for (rf = 0; rf < BOARD_HEIGHT; rf++)
265 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
268 if (flags & F_WHITE_ON_MOVE) {
269 if (!WhitePiece(board[rf][ff])) continue;
271 if (!BlackPiece(board[rf][ff])) continue;
273 m = 0; piece = board[rf][ff];
274 if(PieceToChar(piece) == '~')
275 piece = (ChessSquare) ( DEMOTED piece );
276 if(gameInfo.variant == VariantShogi)
277 piece = (ChessSquare) ( SHOGI piece );
280 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
282 /* can't happen ([HGM] except for faries...) */
286 if(gameInfo.variant == VariantXiangqi) {
287 /* [HGM] capture and move straight ahead in Xiangqi */
288 if (rf < BOARD_HEIGHT-1 &&
289 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
290 callback(board, flags, NormalMove,
291 rf, ff, rf + 1, ff, closure);
293 /* and move sideways when across the river */
294 for (s = -1; s <= 1; s += 2) {
295 if (rf >= BOARD_HEIGHT>>1 &&
296 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
297 !WhitePiece(board[rf][ff+s]) ) {
298 callback(board, flags, NormalMove,
299 rf, ff, rf, ff+s, closure);
304 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
305 callback(board, flags,
306 rf == BOARD_HEIGHT-2 ? WhitePromotionQueen : NormalMove,
307 rf, ff, rf + 1, ff, closure);
309 if (rf == 1 && board[2][ff] == EmptySquare &&
310 gameInfo.variant != VariantShatranj && /* [HGM] */
311 gameInfo.variant != VariantCourier && /* [HGM] */
312 board[3][ff] == EmptySquare ) {
313 callback(board, flags, NormalMove,
314 rf, ff, 3, ff, closure);
316 for (s = -1; s <= 1; s += 2) {
317 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
318 ((flags & F_KRIEGSPIEL_CAPTURE) ||
319 BlackPiece(board[rf + 1][ff + s]))) {
320 callback(board, flags,
321 rf == BOARD_HEIGHT-2 ? WhitePromotionQueen : NormalMove,
322 rf, ff, rf + 1, ff + s, closure);
324 if (rf == BOARD_HEIGHT-4) {
325 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
326 (epfile == ff + s || epfile == EP_UNKNOWN) &&
327 board[BOARD_HEIGHT-4][ff + s] == BlackPawn &&
328 board[BOARD_HEIGHT-3][ff + s] == EmptySquare) {
329 callback(board, flags, WhiteCapturesEnPassant,
330 rf, ff, 5, ff + s, closure);
337 if(gameInfo.variant == VariantXiangqi) {
338 /* [HGM] capture straight ahead in Xiangqi */
339 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
340 callback(board, flags, NormalMove,
341 rf, ff, rf - 1, ff, closure);
343 /* and move sideways when across the river */
344 for (s = -1; s <= 1; s += 2) {
345 if (rf < BOARD_HEIGHT>>1 &&
346 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
347 !BlackPiece(board[rf][ff+s]) ) {
348 callback(board, flags, NormalMove,
349 rf, ff, rf, ff+s, closure);
354 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
355 callback(board, flags,
356 rf == 1 ? BlackPromotionQueen : NormalMove,
357 rf, ff, rf - 1, ff, closure);
359 if (rf == BOARD_HEIGHT-2 && board[BOARD_HEIGHT-3][ff] == EmptySquare &&
360 gameInfo.variant != VariantShatranj && /* [HGM] */
361 gameInfo.variant != VariantCourier && /* [HGM] */
362 board[BOARD_HEIGHT-4][ff] == EmptySquare) {
363 callback(board, flags, NormalMove,
364 rf, ff, BOARD_HEIGHT-4, ff, closure);
366 for (s = -1; s <= 1; s += 2) {
367 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
368 ((flags & F_KRIEGSPIEL_CAPTURE) ||
369 WhitePiece(board[rf - 1][ff + s]))) {
370 callback(board, flags,
371 rf == 1 ? BlackPromotionQueen : NormalMove,
372 rf, ff, rf - 1, ff + s, closure);
375 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
376 (epfile == ff + s || epfile == EP_UNKNOWN) &&
377 board[3][ff + s] == WhitePawn &&
378 board[2][ff + s] == EmptySquare) {
379 callback(board, flags, BlackCapturesEnPassant,
380 rf, ff, 2, ff + s, closure);
391 for (i = -1; i <= 1; i += 2)
392 for (j = -1; j <= 1; j += 2)
393 for (s = 1; s <= 2; s++) {
396 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
397 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
398 && !SameColor(board[rf][ff], board[rt][ft]))
399 callback(board, flags, NormalMove,
400 rf, ff, rt, ft, closure);
404 case SHOGI WhiteKnight:
405 for (s = -1; s <= 1; s += 2) {
406 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
407 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
408 callback(board, flags, NormalMove,
409 rf, ff, rf + 2, ff + s, closure);
414 case SHOGI BlackKnight:
415 for (s = -1; s <= 1; s += 2) {
416 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
417 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
418 callback(board, flags, NormalMove,
419 rf, ff, rf - 2, ff + s, closure);
426 for (d = 0; d <= 1; d++)
427 for (s = -1; s <= 1; s += 2) {
430 rt = rf + (i * s) * d;
431 ft = ff + (i * s) * (1 - d);
432 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
433 if (m == 0 && board[rt][ft] == EmptySquare)
434 callback(board, flags, NormalMove,
435 rf, ff, rt, ft, closure);
436 if (m == 1 && board[rt][ft] != EmptySquare &&
437 !SameColor(board[rf][ff], board[rt][ft]) )
438 callback(board, flags, NormalMove,
439 rf, ff, rt, ft, closure);
440 if (board[rt][ft] != EmptySquare && m++) break;
445 /* Gold General (and all its promoted versions) . First do the */
446 /* diagonal forward steps, then proceed as normal Wazir */
447 case SHOGI WhiteWazir:
448 case SHOGI (PROMOTED WhitePawn):
449 case SHOGI (PROMOTED WhiteKnight):
450 case SHOGI (PROMOTED WhiteQueen):
451 case SHOGI (PROMOTED WhiteFerz):
452 for (s = -1; s <= 1; s += 2) {
453 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
454 !SameColor(board[rf][ff], board[rf + 1][ff + s])) {
455 callback(board, flags, NormalMove,
456 rf, ff, rf + 1, ff + s, closure);
461 case SHOGI BlackWazir:
462 case SHOGI (PROMOTED BlackPawn):
463 case SHOGI (PROMOTED BlackKnight):
464 case SHOGI (PROMOTED BlackQueen):
465 case SHOGI (PROMOTED BlackFerz):
466 for (s = -1; s <= 1; s += 2) {
467 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
468 !SameColor(board[rf][ff], board[rf - 1][ff + s])) {
469 callback(board, flags, NormalMove,
470 rf, ff, rf - 1, ff + s, closure);
477 for (d = 0; d <= 1; d++)
478 for (s = -1; s <= 1; s += 2) {
480 ft = ff + s * (1 - d);
481 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
482 && !SameColor(board[rf][ff], board[rt][ft]) &&
483 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
484 callback(board, flags, NormalMove,
485 rf, ff, rt, ft, closure);
491 /* [HGM] support Shatranj pieces */
492 for (rs = -1; rs <= 1; rs += 2)
493 for (fs = -1; fs <= 1; fs += 2) {
496 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
497 && ( gameInfo.variant != VariantXiangqi ||
498 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
500 && !SameColor(board[rf][ff], board[rt][ft]))
501 callback(board, flags, NormalMove,
502 rf, ff, rt, ft, closure);
506 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
507 case SHOGI WhiteCardinal:
508 case SHOGI BlackCardinal:
511 /* Capablanca Archbishop continues as Knight */
516 /* Shogi Bishops are ordinary Bishops */
517 case SHOGI WhiteBishop:
518 case SHOGI BlackBishop:
521 for (rs = -1; rs <= 1; rs += 2)
522 for (fs = -1; fs <= 1; fs += 2)
526 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
527 if (SameColor(board[rf][ff], board[rt][ft])) break;
528 callback(board, flags, NormalMove,
529 rf, ff, rt, ft, closure);
530 if (board[rt][ft] != EmptySquare) break;
532 if(m==1) goto mounted;
533 if(m==2) goto finishGold;
534 /* Bishop falls through */
537 /* Shogi Lance is unlike anything, and asymmetric at that */
538 case SHOGI WhiteQueen:
542 if (rt >= BOARD_HEIGHT) break;
543 if (SameColor(board[rf][ff], board[rt][ft])) break;
544 callback(board, flags, NormalMove,
545 rf, ff, rt, ft, closure);
546 if (board[rt][ft] != EmptySquare) break;
550 case SHOGI BlackQueen:
555 if (SameColor(board[rf][ff], board[rt][ft])) break;
556 callback(board, flags, NormalMove,
557 rf, ff, rt, ft, closure);
558 if (board[rt][ft] != EmptySquare) break;
562 /* Shogi Dragon King has to continue as Ferz after Rook moves */
563 case SHOGI WhiteDragon:
564 case SHOGI BlackDragon:
567 /* Capablanca Chancellor sets flag to continue as Knight */
572 /* Shogi Rooks are ordinary Rooks */
573 case SHOGI WhiteRook:
574 case SHOGI BlackRook:
577 for (d = 0; d <= 1; d++)
578 for (s = -1; s <= 1; s += 2)
580 rt = rf + (i * s) * d;
581 ft = ff + (i * s) * (1 - d);
582 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
583 if (SameColor(board[rf][ff], board[rt][ft])) break;
584 callback(board, flags, NormalMove,
585 rf, ff, rt, ft, closure);
586 if (board[rt][ft] != EmptySquare) break;
588 if(m==1) goto mounted;
589 if(m==2) goto finishSilver;
594 for (rs = -1; rs <= 1; rs++)
595 for (fs = -1; fs <= 1; fs++) {
596 if (rs == 0 && fs == 0) continue;
600 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
601 if (SameColor(board[rf][ff], board[rt][ft])) break;
602 callback(board, flags, NormalMove,
603 rf, ff, rt, ft, closure);
604 if (board[rt][ft] != EmptySquare) break;
609 /* Shogi Pawn and Silver General: first the Pawn move, */
610 /* then the General continues like a Ferz */
611 case SHOGI WhitePawn:
612 case SHOGI WhiteFerz:
613 if (rf < BOARD_HEIGHT-1 &&
614 !SameColor(board[rf][ff], board[rf + 1][ff]) )
615 callback(board, flags, NormalMove,
616 rf, ff, rf + 1, ff, closure);
617 if(piece != SHOGI WhitePawn) goto finishSilver;
620 case SHOGI BlackPawn:
621 case SHOGI BlackFerz:
623 !SameColor(board[rf][ff], board[rf - 1][ff]) )
624 callback(board, flags, NormalMove,
625 rf, ff, rf - 1, ff, closure);
626 if(piece == SHOGI BlackPawn) break;
631 /* [HGM] support Shatranj pieces */
632 for (rs = -1; rs <= 1; rs += 2)
633 for (fs = -1; fs <= 1; fs += 2) {
636 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
637 if (!SameColor(board[rf][ff], board[rt][ft]) &&
638 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
639 callback(board, flags, NormalMove,
640 rf, ff, rt, ft, closure);
646 m++; // [HGM] superchess: use for Centaur
649 case SHOGI WhiteKing:
650 case SHOGI BlackKing:
654 for (i = -1; i <= 1; i++)
655 for (j = -1; j <= 1; j++) {
656 if (i == 0 && j == 0) continue;
659 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
660 if (SameColor(board[rf][ff], board[rt][ft])) continue;
661 callback(board, flags, NormalMove,
662 rf, ff, rt, ft, closure);
664 if(m==1) goto mounted;
667 case WhiteNightrider:
668 case BlackNightrider:
669 for (i = -1; i <= 1; i += 2)
670 for (j = -1; j <= 1; j += 2)
671 for (s = 1; s <= 2; s++) { int k;
675 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
676 if (SameColor(board[rf][ff], board[rt][ft])) break;
677 callback(board, flags, NormalMove,
678 rf, ff, rt, ft, closure);
679 if (board[rt][ft] != EmptySquare) break;
683 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
689 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
702 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
703 int rf, int ff, int rt, int ft,
706 void GenLegalCallback(board, flags, kind, rf, ff, rt, ft, closure)
713 register GenLegalClosure *cl = (GenLegalClosure *) closure;
715 if (!(flags & F_IGNORE_CHECK) &&
716 CheckTest(board, flags, rf, ff, rt, ft,
717 kind == WhiteCapturesEnPassant ||
718 kind == BlackCapturesEnPassant)) return;
719 if (flags & F_ATOMIC_CAPTURE) {
720 if (board[rt][ft] != EmptySquare ||
721 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
723 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
724 if (board[rf][ff] == king) return;
725 for (r = rt-1; r <= rt+1; r++) {
726 for (f = ft-1; f <= ft+1; f++) {
727 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
728 board[r][f] == king) return;
733 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
740 int captures; // [HGM] losers
741 } LegalityTestClosure;
744 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
745 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
746 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
747 moves that would destroy your own king. The CASTLE_OK flags are
748 true if castling is not yet ruled out by a move of the king or
749 rook. Return TRUE if the player on move is currently in check and
750 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
751 int GenLegal(board, flags, epfile, castlingRights, callback, closure)
755 char castlingRights[];
756 MoveCallback callback;
760 int ff, ft, k, left, right;
761 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
762 ChessSquare wKing = WhiteKing, bKing = BlackKing;
766 GenPseudoLegal(board, flags, epfile, GenLegalCallback, (VOIDSTAR) &cl);
769 CheckTest(board, flags, -1, -1, -1, -1, FALSE)) return TRUE;
771 /* Generate castling moves */
772 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
773 wKing = WhiteUnicorn; bKing = BlackUnicorn;
776 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
777 if ((flags & F_WHITE_ON_MOVE) &&
778 (flags & F_WHITE_KCASTLE_OK) &&
779 board[0][ff] == wKing &&
780 board[0][ff + 1] == EmptySquare &&
781 board[0][ff + 2] == EmptySquare &&
782 board[0][BOARD_RGHT-3] == EmptySquare &&
783 board[0][BOARD_RGHT-2] == EmptySquare &&
784 board[0][BOARD_RGHT-1] == WhiteRook &&
785 castlingRights[0] >= 0 && /* [HGM] check rights */
786 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
788 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
789 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
790 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
791 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
793 callback(board, flags,
794 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
795 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
797 if ((flags & F_WHITE_ON_MOVE) &&
798 (flags & F_WHITE_QCASTLE_OK) &&
799 board[0][ff] == wKing &&
800 board[0][ff - 1] == EmptySquare &&
801 board[0][ff - 2] == EmptySquare &&
802 board[0][BOARD_LEFT+2] == EmptySquare &&
803 board[0][BOARD_LEFT+1] == EmptySquare &&
804 board[0][BOARD_LEFT+0] == WhiteRook &&
805 castlingRights[1] >= 0 && /* [HGM] check rights */
806 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
808 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
809 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
810 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
812 callback(board, flags,
813 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
814 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
816 if (!(flags & F_WHITE_ON_MOVE) &&
817 (flags & F_BLACK_KCASTLE_OK) &&
818 board[BOARD_HEIGHT-1][ff] == bKing &&
819 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
820 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
821 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
822 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
823 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
824 castlingRights[3] >= 0 && /* [HGM] check rights */
825 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
827 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
828 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
829 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
830 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
832 callback(board, flags,
833 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
834 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
836 if (!(flags & F_WHITE_ON_MOVE) &&
837 (flags & F_BLACK_QCASTLE_OK) &&
838 board[BOARD_HEIGHT-1][ff] == bKing &&
839 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
840 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
841 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
842 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
843 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
844 castlingRights[4] >= 0 && /* [HGM] check rights */
845 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
847 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
848 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
849 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
851 callback(board, flags,
852 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
853 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
857 if(gameInfo.variant == VariantFischeRandom) {
859 /* generate all potential FRC castling moves (KxR), ignoring flags */
860 /* [HGM] test if the Rooks we find have castling rights */
863 if ((flags & F_WHITE_ON_MOVE) != 0) {
864 ff = castlingRights[2]; /* King file if we have any rights */
865 if(ff > 0 && board[0][ff] == WhiteKing) {
866 ft = castlingRights[0]; /* Rook file if we have H-side rights */
868 right = BOARD_RGHT-2;
869 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
870 for(k=left; k<=right && ft >= 0; k++) /* first test if blocked */
871 if(k != ft && board[0][k] != EmptySquare) ft = -1;
872 for(k=left; k<right && ft >= 0; k++) /* then if not checked */
873 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = -1;
874 if(ft >= 0 && board[0][ft] == WhiteRook)
875 callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
877 ft = castlingRights[1]; /* Rook file if we have A-side rights */
880 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
881 for(k=left; k<=right && ft >= 0; k++) /* first test if blocked */
882 if(k != ft && board[0][k] != EmptySquare) ft = -1;
883 if(ff > BOARD_LEFT+2)
884 for(k=left+1; k<=right && ft >= 0; k++) /* then if not checked */
885 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = -1;
886 if(ft >= 0 && board[0][ft] == WhiteRook)
887 callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
890 ff = castlingRights[5]; /* King file if we have any rights */
891 if(ff > 0 && board[BOARD_HEIGHT-1][ff] == BlackKing) {
892 ft = castlingRights[3]; /* Rook file if we have H-side rights */
894 right = BOARD_RGHT-2;
895 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
896 for(k=left; k<=right && ft >= 0; k++) /* first test if blocked */
897 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = -1;
898 for(k=left; k<right && ft >= 0; k++) /* then if not checked */
899 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = -1;
900 if(ft >= 0 && board[BOARD_HEIGHT-1][ft] == BlackRook)
901 callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
903 ft = castlingRights[4]; /* Rook file if we have A-side rights */
906 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
907 for(k=left; k<=right && ft >= 0; k++) /* first test if blocked */
908 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = -1;
909 if(ff > BOARD_LEFT+2)
910 for(k=left+1; k<=right && ft >= 0; k++) /* then if not checked */
911 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = -1;
912 if(ft >= 0 && board[BOARD_HEIGHT-1][ft] == BlackRook)
913 callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
929 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
930 int rf, int ff, int rt, int ft,
934 void CheckTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
941 register CheckTestClosure *cl = (CheckTestClosure *) closure;
943 if (rt == cl->rking && ft == cl->fking) cl->check++;
947 /* If the player on move were to move from (rf, ff) to (rt, ft), would
948 he leave himself in check? Or if rf == -1, is the player on move
949 in check now? enPassant must be TRUE if the indicated move is an
950 e.p. capture. The possibility of castling out of a check along the
951 back rank is not accounted for (i.e., we still return nonzero), as
952 this is illegal anyway. Return value is the number of times the
954 int CheckTest(board, flags, rf, ff, rt, ft, enPassant)
957 int rf, ff, rt, ft, enPassant;
960 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
961 ChessSquare captured = EmptySquare;
962 /* Suppress warnings on uninitialized variables */
964 if(gameInfo.variant == VariantXiangqi)
965 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
966 if(gameInfo.variant == VariantKnightmate)
967 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
971 captured = board[rf][ft];
972 board[rf][ft] = EmptySquare;
974 captured = board[rt][ft];
976 board[rt][ft] = board[rf][ff];
977 board[rf][ff] = EmptySquare;
980 /* For compatibility with ICS wild 9, we scan the board in the
981 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
982 and we test only whether that one is in check. */
984 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
985 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
986 if (board[cl.rking][cl.fking] == king) {
987 if(gameInfo.variant == VariantXiangqi) {
988 /* [HGM] In Xiangqi opposing Kings means check as well */
990 dir = (king >= BlackPawn) ? -1 : 1;
991 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
992 board[i][cl.fking] == EmptySquare; i+=dir );
993 if(i>=0 && i<BOARD_HEIGHT &&
994 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
998 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, -1,
999 CheckTestCallback, (VOIDSTAR) &cl);
1000 goto undo_move; /* 2-level break */
1007 board[rf][ff] = board[rt][ft];
1009 board[rf][ft] = captured;
1010 board[rt][ft] = EmptySquare;
1012 board[rt][ft] = captured;
1016 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1020 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1021 int rf, int ff, int rt, int ft,
1024 void LegalityTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1031 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1033 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1034 cl->captures++; // [HGM] losers: count legal captures
1035 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1039 ChessMove LegalityTest(board, flags, epfile, castlingRights, rf, ff, rt, ft, promoChar)
1042 int rf, ff, rt, ft, promoChar;
1043 char castlingRights[];
1045 LegalityTestClosure cl; ChessSquare piece = board[rf][ff];
1047 /* [HGM] Lance, Cobra and Falcon are wildcard pieces; consider all their moves legal */
1048 /* (perhaps we should disallow moves that obviously leave us in check?) */
1049 if(piece == WhiteFalcon || piece == BlackFalcon ||
1050 piece == WhiteCobra || piece == BlackCobra ||
1051 piece == WhiteLance || piece == BlackLance)
1052 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1058 cl.kind = IllegalMove;
1059 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1060 GenLegal(board, flags, epfile, castlingRights, LegalityTestCallback, (VOIDSTAR) &cl);
1061 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1062 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1063 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1065 if(gameInfo.variant == VariantShogi) {
1066 /* [HGM] Shogi promotions. '=' means defer */
1067 if(rf != DROP_RANK && cl.kind == NormalMove) {
1068 ChessSquare piece = board[rf][ff];
1070 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1071 if(promoChar != NULLCHAR && promoChar != 'x' &&
1072 promoChar != '+' && promoChar != '=' &&
1073 ToUpper(PieceToChar(PROMOTED piece)) != ToUpper(promoChar) )
1074 cl.kind = IllegalMove;
1075 else if(flags & F_WHITE_ON_MOVE) {
1076 if( (int) piece < (int) WhiteWazir &&
1077 (rf > BOARD_HEIGHT-4 || rt > BOARD_HEIGHT-4) ) {
1078 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1079 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1080 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotionKnight;
1081 else /* promotion optional, default is promote */
1082 cl.kind = promoChar == '=' ? NormalMove : WhitePromotionQueen;
1084 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1085 NormalMove : IllegalMove;
1087 if( (int) piece < (int) BlackWazir && (rf < 3 || rt < 3) ) {
1088 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1089 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1090 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotionKnight;
1091 else /* promotion optional, default is promote */
1092 cl.kind = promoChar == '=' ? NormalMove : BlackPromotionQueen;
1094 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1095 NormalMove : IllegalMove;
1099 if (promoChar != NULLCHAR && promoChar != 'x') {
1100 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1101 if (cl.kind == WhitePromotionQueen || cl.kind == BlackPromotionQueen) {
1103 PromoCharToMoveType((flags & F_WHITE_ON_MOVE) != 0, promoChar);
1105 cl.kind = IllegalMove;
1108 /* [HGM] For promotions, 'ToQueen' = optional, 'ToKnight' = mandatory */
1116 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1117 int rf, int ff, int rt, int ft,
1120 void MateTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1127 register MateTestClosure *cl = (MateTestClosure *) closure;
1132 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1133 int MateTest(board, flags, epfile, castlingRights)
1136 char castlingRights[];
1139 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1140 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1142 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1143 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1144 nrKing += (board[r][f] == king); // stm has king
1145 if( board[r][f] != EmptySquare ) {
1146 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1152 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1153 case VariantShatranj:
1154 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1158 if(nrKing == 0) return MT_NOKING;
1161 if(myPieces == 1) return MT_BARE;
1164 inCheck = GenLegal(board, flags, epfile, castlingRights, MateTestCallback, (VOIDSTAR) &cl);
1165 // [HGM] 3check: yet to do!
1167 return inCheck ? MT_CHECK : MT_NONE;
1169 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1170 return myPieces == hisPieces ? MT_STALEMATE :
1171 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1172 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1173 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1175 return inCheck ? MT_CHECKMATE
1176 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj) ?
1177 MT_STAINMATE : MT_STALEMATE;
1182 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1183 int rf, int ff, int rt, int ft,
1186 void DisambiguateCallback(board, flags, kind, rf, ff, rt, ft, closure)
1193 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1194 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1196 // [HGM] wild: for wild-card pieces rt and rf are dummies
1197 if(piece == WhiteFalcon || piece == BlackFalcon ||
1198 piece == WhiteCobra || piece == BlackCobra ||
1199 piece == WhiteLance || piece == BlackLance)
1202 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1203 || PieceToChar(board[rf][ff]) == '~'
1204 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1206 (cl->rfIn == -1 || cl->rfIn == rf) &&
1207 (cl->ffIn == -1 || cl->ffIn == ff) &&
1208 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1209 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1212 cl->piece = board[rf][ff];
1215 cl->rt = wildCard ? cl->rtIn : rt;
1216 cl->ft = wildCard ? cl->ftIn : ft;
1221 void Disambiguate(board, flags, epfile, closure)
1224 DisambiguateClosure *closure;
1226 int illegal = 0; char c = closure->promoCharIn;
1229 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1230 closure->kind = ImpossibleMove;
1232 GenLegal(board, flags, epfile, initialRights, DisambiguateCallback, (VOIDSTAR) closure);
1233 if (closure->count == 0) {
1234 /* See if it's an illegal move due to check */
1236 GenLegal(board, flags|F_IGNORE_CHECK, epfile, initialRights, DisambiguateCallback,
1237 (VOIDSTAR) closure);
1238 if (closure->count == 0) {
1239 /* No, it's not even that */
1244 if(gameInfo.variant == VariantShogi) {
1245 /* [HGM] Shogi promotions. '=' means defer */
1246 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
1247 ChessSquare piece = closure->piece;
1248 if(c != NULLCHAR && c != 'x' && c != '+' && c != '=' &&
1249 ToUpper(PieceToChar(PROMOTED piece)) != ToUpper(c) )
1250 closure->kind = IllegalMove;
1251 else if(flags & F_WHITE_ON_MOVE) {
1252 if( (int) piece < (int) WhiteWazir &&
1253 (closure->rf > BOARD_HEIGHT-4 || closure->rt > BOARD_HEIGHT-4) ) {
1254 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
1255 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
1256 closure->kind = c == '=' ? IllegalMove : WhitePromotionKnight;
1257 else /* promotion optional, default is promote */
1258 closure->kind = c == '=' ? NormalMove : WhitePromotionQueen;
1260 } else closure->kind = (c == NULLCHAR || c == 'x' || c == '=') ?
1261 NormalMove : IllegalMove;
1263 if( (int) piece < (int) BlackWazir && (closure->rf < 3 || closure->rt < 3) ) {
1264 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
1265 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
1266 closure->kind = c == '=' ? IllegalMove : BlackPromotionKnight;
1267 else /* promotion optional, default is promote */
1268 closure->kind = c == '=' ? NormalMove : BlackPromotionQueen;
1270 } else closure->kind = (c == NULLCHAR || c == 'x' || c == '=') ?
1271 NormalMove : IllegalMove;
1275 if (closure->promoCharIn != NULLCHAR && closure->promoCharIn != 'x') {
1276 if (closure->kind == WhitePromotionQueen
1277 || closure->kind == BlackPromotionQueen) {
1279 PromoCharToMoveType((flags & F_WHITE_ON_MOVE) != 0,
1280 closure->promoCharIn);
1282 closure->kind = IllegalMove;
1285 /* [HGM] returns 'q' for optional promotion, 'n' for mandatory */
1286 if(closure->promoCharIn != '=')
1287 closure->promoChar = ToLower(closure->promoCharIn);
1288 else closure->promoChar = '=';
1289 if (closure->promoChar == 'x') closure->promoChar = NULLCHAR;
1290 if (closure->count > 1) {
1291 closure->kind = AmbiguousMove;
1294 /* Note: If more than one illegal move matches, but no legal
1295 moves, we return IllegalMove, not AmbiguousMove. Caller
1296 can look at closure->count to detect this.
1298 closure->kind = IllegalMove;
1300 if(closure->kind == IllegalMove)
1301 /* [HGM] might be a variant we don't understand, pass on promotion info */
1302 closure->promoChar = ToLower(closure->promoCharIn);
1315 } CoordsToAlgebraicClosure;
1317 extern void CoordsToAlgebraicCallback P((Board board, int flags,
1318 ChessMove kind, int rf, int ff,
1319 int rt, int ft, VOIDSTAR closure));
1321 void CoordsToAlgebraicCallback(board, flags, kind, rf, ff, rt, ft, closure)
1328 register CoordsToAlgebraicClosure *cl =
1329 (CoordsToAlgebraicClosure *) closure;
1331 if (rt == cl->rt && ft == cl->ft &&
1332 (board[rf][ff] == cl->piece
1333 || PieceToChar(board[rf][ff]) == '~' &&
1334 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
1338 cl->kind = kind; /* this is the move we want */
1340 cl->file++; /* need file to rule out this move */
1344 cl->rank++; /* need rank to rule out this move */
1346 cl->either++; /* rank or file will rule out this move */
1352 /* Convert coordinates to normal algebraic notation.
1353 promoChar must be NULLCHAR or 'x' if not a promotion.
1355 ChessMove CoordsToAlgebraic(board, flags, epfile,
1356 rf, ff, rt, ft, promoChar, out)
1365 char *outp = out, c;
1366 CoordsToAlgebraicClosure cl;
1368 if (rf == DROP_RANK) {
1369 /* Bughouse piece drop */
1370 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
1375 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1377 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
1380 if (promoChar == 'x') promoChar = NULLCHAR;
1381 piece = board[rf][ff];
1382 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
1387 kind = LegalityTest(board, flags, epfile, initialRights, rf, ff, rt, ft, promoChar);
1388 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1389 /* Keep short notation if move is illegal only because it
1390 leaves the player in check, but still return IllegalMove */
1391 kind = LegalityTest(board, flags|F_IGNORE_CHECK, epfile, initialRights,
1392 rf, ff, rt, ft, promoChar);
1393 if (kind == IllegalMove) break;
1398 if (ff == ft && board[rt][ft] == EmptySquare) { /* [HGM] Xiangqi has straight noncapts! */
1399 /* Non-capture; use style "e5" */
1402 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1404 /* Capture; use style "exd5" */
1405 if(gameInfo.variant != VariantXiangqi || board[rt][ft] != EmptySquare )
1406 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
1410 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1412 /* Use promotion suffix style "=Q" */
1414 if (promoChar != NULLCHAR) {
1415 if(gameInfo.variant == VariantShogi) {
1416 /* [HGM] ... but not in Shogi! */
1417 *outp++ = promoChar == '=' ? '=' : '+';
1420 *outp++ = ToUpper(promoChar);
1429 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
1430 /* Code added by Tord: FRC castling. */
1431 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
1432 (piece == BlackKing && board[rt][ft] == BlackRook)) {
1433 if(ft > ff) strcpy(out, "O-O"); else strcpy(out, "O-O-O");
1434 return LegalityTest(board, flags, epfile, initialRights,
1435 rf, ff, rt, ft, promoChar);
1437 /* End of code added by Tord */
1438 /* Test for castling or ICS wild castling */
1439 /* Use style "O-O" (oh-oh) for PGN compatibility */
1440 else if (rf == rt &&
1441 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
1442 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
1443 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
1444 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
1447 strcpy(out, "O-O-O");
1449 /* This notation is always unambiguous, unless there are
1450 kings on both the d and e files, with "wild castling"
1451 possible for the king on the d file and normal castling
1452 possible for the other. ICS rules for wild 9
1453 effectively make castling illegal for either king in
1454 this situation. So I am not going to worry about it;
1455 I'll just generate an ambiguous O-O in this case.
1457 return LegalityTest(board, flags, epfile, initialRights,
1458 rf, ff, rt, ft, promoChar);
1461 /* else fall through */
1469 cl.kind = IllegalMove;
1470 cl.rank = cl.file = cl.either = 0;
1471 GenLegal(board, flags, epfile, initialRights,
1472 CoordsToAlgebraicCallback, (VOIDSTAR) &cl);
1474 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1475 /* Generate pretty moves for moving into check, but
1476 still return IllegalMove.
1478 GenLegal(board, flags|F_IGNORE_CHECK, epfile, initialRights,
1479 CoordsToAlgebraicCallback, (VOIDSTAR) &cl);
1480 if (cl.kind == IllegalMove) break;
1481 cl.kind = IllegalMove;
1484 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
1485 else "Ngf3" or "Ngxf7",
1486 else "N1f3" or "N5xf7",
1487 else "Ng1f3" or "Ng5xf7".
1489 c = PieceToChar(piece) ;
1490 if( c == '~' || c == '+') {
1491 /* [HGM] print nonexistent piece as its demoted version */
1492 piece = (ChessSquare) (DEMOTED piece);
1494 if(c=='+') *outp++ = c;
1495 *outp++ = ToUpper(PieceToChar(piece));
1497 if (cl.file || (cl.either && !cl.rank)) {
1503 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1506 if(board[rt][ft] != EmptySquare)
1512 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1514 if (gameInfo.variant == VariantShogi) {
1515 /* [HGM] in Shogi non-pawns can promote */
1516 if(flags & F_WHITE_ON_MOVE) {
1517 if( (int) cl.piece < (int) WhiteWazir &&
1518 (rf > BOARD_HEIGHT-4 || rt > BOARD_HEIGHT-4) ) {
1519 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1520 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1521 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotionKnight;
1522 else cl.kind = WhitePromotionQueen; /* promotion optional */
1524 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1525 NormalMove : IllegalMove;
1527 if( (int) cl.piece < (int) BlackWazir && (rf < 3 || rt < 3) ) {
1528 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1529 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1530 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotionKnight;
1531 else cl.kind = BlackPromotionQueen; /* promotion optional */
1532 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1533 NormalMove : IllegalMove;
1535 if(cl.kind == WhitePromotionQueen || cl.kind == BlackPromotionQueen) {
1536 /* for optional promotions append '+' or '=' */
1537 if(promoChar == '=') {
1539 cl.kind = NormalMove;
1540 } else *outp++ = '+';
1542 } else if(cl.kind == IllegalMove) {
1543 /* Illegal move specifies any given promotion */
1544 if(promoChar != NULLCHAR && promoChar != 'x') {
1546 *outp++ = ToUpper(promoChar);
1553 /* [HGM] Always long notation for fairies we don't know */
1558 case WhiteGrasshopper:
1559 case BlackGrasshopper:
1561 /* Moving a nonexistent piece */
1565 /* Not a legal move, even ignoring check.
1566 If there was a piece on the from square,
1567 use style "Ng1g3" or "Ng1xe8";
1568 if there was a pawn or nothing (!),
1569 use style "g1g3" or "g1xe8". Use "x"
1570 if a piece was on the to square, even
1571 a piece of the same color.
1574 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
1575 *outp++ = ToUpper(PieceToChar(piece));
1580 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1581 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
1585 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1586 /* Use promotion suffix style "=Q" */
1587 if (promoChar != NULLCHAR && promoChar != 'x') {
1589 *outp++ = ToUpper(promoChar);
1596 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
1605 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
1607 int preyStackPointer, chaseStackPointer;
1610 char rf, ff, rt, ft;
1620 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
1622 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
1623 int rf, int ff, int rt, int ft,
1626 void AttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1632 { // For adding captures that can lead to chase indictment to the chaseStack
1633 if(board[rt][ft] == EmptySquare) return; // non-capture
1634 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
1635 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
1636 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
1637 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
1638 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
1639 chaseStack[chaseStackPointer].rf = rf;
1640 chaseStack[chaseStackPointer].ff = ff;
1641 chaseStack[chaseStackPointer].rt = rt;
1642 chaseStack[chaseStackPointer].ft = ft;
1643 chaseStackPointer++;
1646 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
1647 int rf, int ff, int rt, int ft,
1650 void ExistingAttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1656 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
1658 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
1660 if(board[rt][ft] == EmptySquare) return; // no capture
1661 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
1662 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
1664 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
1665 for(i=0; i<chaseStackPointer; i++) {
1666 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
1667 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
1668 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
1669 chaseStack[i] = chaseStack[--chaseStackPointer];
1675 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
1676 int rf, int ff, int rt, int ft,
1679 void ProtectedCallback(board, flags, kind, rf, ff, rt, ft, closure)
1685 { // for determining if a piece (given through the closure) is protected
1686 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
1688 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
1689 if(appData.debugMode && board[rt][ft] != EmptySquare)
1690 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
1693 extern char moveList[MAX_MOVES][MOVE_LEN];
1695 int PerpetualChase(int first, int last)
1696 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
1699 ChessSquare captured;
1701 preyStackPointer = 0; // clear stack of chased pieces
1702 for(i=first; i<last; i+=2) { // for all positions with same side to move
1703 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
1704 chaseStackPointer = 0; // clear stack that is going to hold possible chases
1705 // determine all captures possible after the move, and put them on chaseStack
1706 GenLegal(boards[i+1], PosFlags(i), EP_NONE, initialRights, AttacksCallback, &cl);
1707 if(appData.debugMode) { int n;
1708 for(n=0; n<chaseStackPointer; n++)
1709 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1710 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1711 fprintf(debugFP, ": all capts\n");
1713 // determine all captures possible before the move, and delete them from chaseStack
1714 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
1715 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
1716 cl.rt = moveList[i][3]-ONE;
1717 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
1718 GenLegal(boards[i], PosFlags(i), EP_NONE, initialRights, ExistingAttacksCallback, &cl);
1719 if(appData.debugMode) { int n;
1720 for(n=0; n<chaseStackPointer; n++)
1721 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1722 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1723 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
1725 // chaseSack now contains all captures made possible by the move
1726 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
1727 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1728 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1730 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
1731 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
1733 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
1734 continue; // C or H attack on R is always chase; leave on chaseStack
1736 if(attacker == victim) {
1737 if(LegalityTest(boards[i+1], PosFlags(i+1), EP_NONE, initialRights, chaseStack[j].rt,
1738 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
1739 // we can capture back with equal piece, so this is no chase but a sacrifice
1740 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
1741 j--; /* ! */ continue;
1746 // the attack is on a lower piece, or on a pinned or blocked equal one
1747 // test if the victim is protected by a true protector. First make the capture.
1748 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1749 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1750 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
1751 // Then test if the opponent can recapture
1752 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
1753 cl.rt = chaseStack[j].rt;
1754 cl.ft = chaseStack[j].ft;
1755 if(appData.debugMode) {
1756 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
1758 GenLegal(boards[i+1], PosFlags(i+1), EP_NONE, initialRights, ProtectedCallback, &cl); // try all moves
1759 // unmake the capture
1760 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1761 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
1762 // if a recapture was found, piece is protected, and we are not chasing it.
1763 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
1764 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
1768 // chaseStack now contains all moves that chased
1769 if(appData.debugMode) { int n;
1770 for(n=0; n<chaseStackPointer; n++)
1771 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1772 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1773 fprintf(debugFP, ": chases\n");
1775 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
1776 for(j=0; j<chaseStackPointer; j++) {
1777 preyStack[j].rank = chaseStack[j].rt;
1778 preyStack[j].file = chaseStack[j].ft;
1780 preyStackPointer = chaseStackPointer;
1783 for(j=0; j<chaseStackPointer; j++) {
1784 for(k=0; k<preyStackPointer; k++) {
1785 // search the victim of each chase move on the preyStack (first occurrence)
1786 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
1787 if(k < tail) break; // piece was already identified as still being chased
1788 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
1789 preyStack[tail] = preyStack[k]; // by swapping
1790 preyStack[k] = preyStack[preyStackPointer];
1796 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
1797 if(appData.debugMode) { int n;
1798 for(n=0; n<preyStackPointer; n++)
1799 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
1800 fprintf(debugFP, "always chased upto ply %d\n", i);
1802 // now adjust the location of the chased pieces according to opponent move
1803 for(j=0; j<preyStackPointer; j++) {
1804 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
1805 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
1806 preyStack[j].rank = moveList[i+1][3]-ONE;
1807 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
1812 return preyStackPointer; // if any piece was left on preyStack, it has been perpetually chased