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 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;
263 int promoRank = gameInfo.variant == VariantMakruk ? 3 : 1;
265 for (rf = 0; rf < BOARD_HEIGHT; rf++)
266 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
269 if (flags & F_WHITE_ON_MOVE) {
270 if (!WhitePiece(board[rf][ff])) continue;
272 if (!BlackPiece(board[rf][ff])) continue;
274 m = 0; piece = board[rf][ff];
275 if(PieceToChar(piece) == '~')
276 piece = (ChessSquare) ( DEMOTED piece );
277 if(gameInfo.variant == VariantShogi)
278 piece = (ChessSquare) ( SHOGI piece );
281 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
283 /* can't happen ([HGM] except for faries...) */
287 if(gameInfo.variant == VariantXiangqi) {
288 /* [HGM] capture and move straight ahead in Xiangqi */
289 if (rf < BOARD_HEIGHT-1 &&
290 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
291 callback(board, flags, NormalMove,
292 rf, ff, rf + 1, ff, closure);
294 /* and move sideways when across the river */
295 for (s = -1; s <= 1; s += 2) {
296 if (rf >= BOARD_HEIGHT>>1 &&
297 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
298 !WhitePiece(board[rf][ff+s]) ) {
299 callback(board, flags, NormalMove,
300 rf, ff, rf, ff+s, closure);
305 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
306 callback(board, flags,
307 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotionQueen : NormalMove,
308 rf, ff, rf + 1, ff, closure);
310 if (rf == 1 && board[2][ff] == EmptySquare &&
311 gameInfo.variant != VariantShatranj && /* [HGM] */
312 gameInfo.variant != VariantCourier && /* [HGM] */
313 board[3][ff] == EmptySquare ) {
314 callback(board, flags, NormalMove,
315 rf, ff, 3, ff, closure);
317 for (s = -1; s <= 1; s += 2) {
318 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
319 ((flags & F_KRIEGSPIEL_CAPTURE) ||
320 BlackPiece(board[rf + 1][ff + s]))) {
321 callback(board, flags,
322 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotionQueen : NormalMove,
323 rf, ff, rf + 1, ff + s, closure);
325 if (rf == BOARD_HEIGHT-4) {
326 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
327 (epfile == ff + s || epfile == EP_UNKNOWN) &&
328 board[BOARD_HEIGHT-4][ff + s] == BlackPawn &&
329 board[BOARD_HEIGHT-3][ff + s] == EmptySquare) {
330 callback(board, flags, WhiteCapturesEnPassant,
331 rf, ff, 5, ff + s, closure);
338 if(gameInfo.variant == VariantXiangqi) {
339 /* [HGM] capture straight ahead in Xiangqi */
340 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
341 callback(board, flags, NormalMove,
342 rf, ff, rf - 1, ff, closure);
344 /* and move sideways when across the river */
345 for (s = -1; s <= 1; s += 2) {
346 if (rf < BOARD_HEIGHT>>1 &&
347 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
348 !BlackPiece(board[rf][ff+s]) ) {
349 callback(board, flags, NormalMove,
350 rf, ff, rf, ff+s, closure);
355 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
356 callback(board, flags,
357 rf <= promoRank ? BlackPromotionQueen : NormalMove,
358 rf, ff, rf - 1, ff, closure);
360 if (rf == BOARD_HEIGHT-2 && board[BOARD_HEIGHT-3][ff] == EmptySquare &&
361 gameInfo.variant != VariantShatranj && /* [HGM] */
362 gameInfo.variant != VariantCourier && /* [HGM] */
363 board[BOARD_HEIGHT-4][ff] == EmptySquare) {
364 callback(board, flags, NormalMove,
365 rf, ff, BOARD_HEIGHT-4, ff, closure);
367 for (s = -1; s <= 1; s += 2) {
368 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
369 ((flags & F_KRIEGSPIEL_CAPTURE) ||
370 WhitePiece(board[rf - 1][ff + s]))) {
371 callback(board, flags,
372 rf <= promoRank ? BlackPromotionQueen : NormalMove,
373 rf, ff, rf - 1, ff + s, closure);
376 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
377 (epfile == ff + s || epfile == EP_UNKNOWN) &&
378 board[3][ff + s] == WhitePawn &&
379 board[2][ff + s] == EmptySquare) {
380 callback(board, flags, BlackCapturesEnPassant,
381 rf, ff, 2, ff + s, closure);
392 for (i = -1; i <= 1; i += 2)
393 for (j = -1; j <= 1; j += 2)
394 for (s = 1; s <= 2; s++) {
397 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
398 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
399 && !SameColor(board[rf][ff], board[rt][ft]))
400 callback(board, flags, NormalMove,
401 rf, ff, rt, ft, closure);
405 case SHOGI WhiteKnight:
406 for (s = -1; s <= 1; s += 2) {
407 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
408 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
409 callback(board, flags, NormalMove,
410 rf, ff, rf + 2, ff + s, closure);
415 case SHOGI BlackKnight:
416 for (s = -1; s <= 1; s += 2) {
417 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
418 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
419 callback(board, flags, NormalMove,
420 rf, ff, rf - 2, ff + s, closure);
427 for (d = 0; d <= 1; d++)
428 for (s = -1; s <= 1; s += 2) {
431 rt = rf + (i * s) * d;
432 ft = ff + (i * s) * (1 - d);
433 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
434 if (m == 0 && board[rt][ft] == EmptySquare)
435 callback(board, flags, NormalMove,
436 rf, ff, rt, ft, closure);
437 if (m == 1 && board[rt][ft] != EmptySquare &&
438 !SameColor(board[rf][ff], board[rt][ft]) )
439 callback(board, flags, NormalMove,
440 rf, ff, rt, ft, closure);
441 if (board[rt][ft] != EmptySquare && m++) break;
446 /* Gold General (and all its promoted versions) . First do the */
447 /* diagonal forward steps, then proceed as normal Wazir */
448 case SHOGI WhiteWazir:
449 case SHOGI (PROMOTED WhitePawn):
450 case SHOGI (PROMOTED WhiteKnight):
451 case SHOGI (PROMOTED WhiteQueen):
452 case SHOGI (PROMOTED WhiteFerz):
453 for (s = -1; s <= 1; s += 2) {
454 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
455 !SameColor(board[rf][ff], board[rf + 1][ff + s])) {
456 callback(board, flags, NormalMove,
457 rf, ff, rf + 1, ff + s, closure);
462 case SHOGI BlackWazir:
463 case SHOGI (PROMOTED BlackPawn):
464 case SHOGI (PROMOTED BlackKnight):
465 case SHOGI (PROMOTED BlackQueen):
466 case SHOGI (PROMOTED BlackFerz):
467 for (s = -1; s <= 1; s += 2) {
468 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
469 !SameColor(board[rf][ff], board[rf - 1][ff + s])) {
470 callback(board, flags, NormalMove,
471 rf, ff, rf - 1, ff + s, closure);
478 for (d = 0; d <= 1; d++)
479 for (s = -1; s <= 1; s += 2) {
481 ft = ff + s * (1 - d);
482 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
483 && !SameColor(board[rf][ff], board[rt][ft]) &&
484 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
485 callback(board, flags, NormalMove,
486 rf, ff, rt, ft, closure);
492 /* [HGM] support Shatranj pieces */
493 for (rs = -1; rs <= 1; rs += 2)
494 for (fs = -1; fs <= 1; fs += 2) {
497 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
498 && ( gameInfo.variant != VariantXiangqi ||
499 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
501 && !SameColor(board[rf][ff], board[rt][ft]))
502 callback(board, flags, NormalMove,
503 rf, ff, rt, ft, closure);
507 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
508 case SHOGI WhiteCardinal:
509 case SHOGI BlackCardinal:
512 /* Capablanca Archbishop continues as Knight */
517 /* Shogi Bishops are ordinary Bishops */
518 case SHOGI WhiteBishop:
519 case SHOGI BlackBishop:
522 for (rs = -1; rs <= 1; rs += 2)
523 for (fs = -1; fs <= 1; fs += 2)
527 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
528 if (SameColor(board[rf][ff], board[rt][ft])) break;
529 callback(board, flags, NormalMove,
530 rf, ff, rt, ft, closure);
531 if (board[rt][ft] != EmptySquare) break;
533 if(m==1) goto mounted;
534 if(m==2) goto finishGold;
535 /* Bishop falls through */
538 /* Shogi Lance is unlike anything, and asymmetric at that */
539 case SHOGI WhiteQueen:
543 if (rt >= BOARD_HEIGHT) break;
544 if (SameColor(board[rf][ff], board[rt][ft])) break;
545 callback(board, flags, NormalMove,
546 rf, ff, rt, ft, closure);
547 if (board[rt][ft] != EmptySquare) break;
551 case SHOGI BlackQueen:
556 if (SameColor(board[rf][ff], board[rt][ft])) break;
557 callback(board, flags, NormalMove,
558 rf, ff, rt, ft, closure);
559 if (board[rt][ft] != EmptySquare) break;
563 /* Shogi Dragon King has to continue as Ferz after Rook moves */
564 case SHOGI WhiteDragon:
565 case SHOGI BlackDragon:
568 /* Capablanca Chancellor sets flag to continue as Knight */
573 /* Shogi Rooks are ordinary Rooks */
574 case SHOGI WhiteRook:
575 case SHOGI BlackRook:
578 for (d = 0; d <= 1; d++)
579 for (s = -1; s <= 1; s += 2)
581 rt = rf + (i * s) * d;
582 ft = ff + (i * s) * (1 - d);
583 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
584 if (SameColor(board[rf][ff], board[rt][ft])) break;
585 callback(board, flags, NormalMove,
586 rf, ff, rt, ft, closure);
587 if (board[rt][ft] != EmptySquare) break;
589 if(m==1) goto mounted;
590 if(m==2) goto finishSilver;
595 for (rs = -1; rs <= 1; rs++)
596 for (fs = -1; fs <= 1; fs++) {
597 if (rs == 0 && fs == 0) continue;
601 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
602 if (SameColor(board[rf][ff], board[rt][ft])) break;
603 callback(board, flags, NormalMove,
604 rf, ff, rt, ft, closure);
605 if (board[rt][ft] != EmptySquare) break;
610 /* Shogi Pawn and Silver General: first the Pawn move, */
611 /* then the General continues like a Ferz */
613 if(gameInfo.variant != VariantMakruk) goto commoner;
614 case SHOGI WhitePawn:
615 case SHOGI WhiteFerz:
616 if (rf < BOARD_HEIGHT-1 &&
617 !SameColor(board[rf][ff], board[rf + 1][ff]) )
618 callback(board, flags, NormalMove,
619 rf, ff, rf + 1, ff, closure);
620 if(piece != SHOGI WhitePawn) goto finishSilver;
624 if(gameInfo.variant != VariantMakruk) goto commoner;
625 case SHOGI BlackPawn:
626 case SHOGI BlackFerz:
628 !SameColor(board[rf][ff], board[rf - 1][ff]) )
629 callback(board, flags, NormalMove,
630 rf, ff, rf - 1, ff, closure);
631 if(piece == SHOGI BlackPawn) break;
636 /* [HGM] support Shatranj pieces */
637 for (rs = -1; rs <= 1; rs += 2)
638 for (fs = -1; fs <= 1; fs += 2) {
641 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
642 if (!SameColor(board[rf][ff], board[rt][ft]) &&
643 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
644 callback(board, flags, NormalMove,
645 rf, ff, rt, ft, closure);
651 m++; // [HGM] superchess: use for Centaur
653 case SHOGI WhiteKing:
654 case SHOGI BlackKing:
658 for (i = -1; i <= 1; i++)
659 for (j = -1; j <= 1; j++) {
660 if (i == 0 && j == 0) continue;
663 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
664 if (SameColor(board[rf][ff], board[rt][ft])) continue;
665 callback(board, flags, NormalMove,
666 rf, ff, rt, ft, closure);
668 if(m==1) goto mounted;
671 case WhiteNightrider:
672 case BlackNightrider:
673 for (i = -1; i <= 1; i += 2)
674 for (j = -1; j <= 1; j += 2)
675 for (s = 1; s <= 2; s++) { int k;
679 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
680 if (SameColor(board[rf][ff], board[rt][ft])) break;
681 callback(board, flags, NormalMove,
682 rf, ff, rt, ft, closure);
683 if (board[rt][ft] != EmptySquare) break;
687 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
693 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
706 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
707 int rf, int ff, int rt, int ft,
710 void GenLegalCallback(board, flags, kind, rf, ff, rt, ft, closure)
717 register GenLegalClosure *cl = (GenLegalClosure *) closure;
719 if (!(flags & F_IGNORE_CHECK) &&
720 CheckTest(board, flags, rf, ff, rt, ft,
721 kind == WhiteCapturesEnPassant ||
722 kind == BlackCapturesEnPassant)) return;
723 if (flags & F_ATOMIC_CAPTURE) {
724 if (board[rt][ft] != EmptySquare ||
725 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
727 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
728 if (board[rf][ff] == king) return;
729 for (r = rt-1; r <= rt+1; r++) {
730 for (f = ft-1; f <= ft+1; f++) {
731 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
732 board[r][f] == king) return;
737 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
744 int captures; // [HGM] losers
745 } LegalityTestClosure;
748 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
749 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
750 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
751 moves that would destroy your own king. The CASTLE_OK flags are
752 true if castling is not yet ruled out by a move of the king or
753 rook. Return TRUE if the player on move is currently in check and
754 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
755 int GenLegal(board, flags, epfile, castlingRights, callback, closure)
759 char castlingRights[];
760 MoveCallback callback;
764 int ff, ft, k, left, right;
765 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
766 ChessSquare wKing = WhiteKing, bKing = BlackKing;
770 GenPseudoLegal(board, flags, epfile, GenLegalCallback, (VOIDSTAR) &cl);
773 CheckTest(board, flags, -1, -1, -1, -1, FALSE)) return TRUE;
775 /* Generate castling moves */
776 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
777 wKing = WhiteUnicorn; bKing = BlackUnicorn;
780 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
781 if ((flags & F_WHITE_ON_MOVE) &&
782 (flags & F_WHITE_KCASTLE_OK) &&
783 board[0][ff] == wKing &&
784 board[0][ff + 1] == EmptySquare &&
785 board[0][ff + 2] == EmptySquare &&
786 board[0][BOARD_RGHT-3] == EmptySquare &&
787 board[0][BOARD_RGHT-2] == EmptySquare &&
788 board[0][BOARD_RGHT-1] == WhiteRook &&
789 castlingRights[0] >= 0 && /* [HGM] check rights */
790 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
792 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
793 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
794 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
795 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
797 callback(board, flags,
798 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
799 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
801 if ((flags & F_WHITE_ON_MOVE) &&
802 (flags & F_WHITE_QCASTLE_OK) &&
803 board[0][ff] == wKing &&
804 board[0][ff - 1] == EmptySquare &&
805 board[0][ff - 2] == EmptySquare &&
806 board[0][BOARD_LEFT+2] == EmptySquare &&
807 board[0][BOARD_LEFT+1] == EmptySquare &&
808 board[0][BOARD_LEFT+0] == WhiteRook &&
809 castlingRights[1] >= 0 && /* [HGM] check rights */
810 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
812 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
813 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
814 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
816 callback(board, flags,
817 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
818 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
820 if (!(flags & F_WHITE_ON_MOVE) &&
821 (flags & F_BLACK_KCASTLE_OK) &&
822 board[BOARD_HEIGHT-1][ff] == bKing &&
823 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
824 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
825 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
826 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
827 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
828 castlingRights[3] >= 0 && /* [HGM] check rights */
829 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
831 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
832 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
833 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
834 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
836 callback(board, flags,
837 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
838 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
840 if (!(flags & F_WHITE_ON_MOVE) &&
841 (flags & F_BLACK_QCASTLE_OK) &&
842 board[BOARD_HEIGHT-1][ff] == bKing &&
843 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
844 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
845 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
846 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
847 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
848 castlingRights[4] >= 0 && /* [HGM] check rights */
849 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
851 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
852 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
853 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
855 callback(board, flags,
856 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
857 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
861 if(flags & F_FRC_TYPE_CASTLING) {
863 /* generate all potential FRC castling moves (KxR), ignoring flags */
864 /* [HGM] test if the Rooks we find have castling rights */
867 if ((flags & F_WHITE_ON_MOVE) != 0) {
868 ff = castlingRights[2]; /* King file if we have any rights */
869 if(ff > 0 && board[0][ff] == WhiteKing) {
870 ft = castlingRights[0]; /* Rook file if we have H-side rights */
872 right = BOARD_RGHT-2;
873 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
874 for(k=left; k<=right && ft >= 0; k++) /* first test if blocked */
875 if(k != ft && board[0][k] != EmptySquare) ft = -1;
876 for(k=left; k<right && ft >= 0; k++) /* then if not checked */
877 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = -1;
878 if(ft >= 0 && board[0][ft] == WhiteRook)
879 callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
881 ft = castlingRights[1]; /* Rook file if we have A-side rights */
884 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
885 for(k=left; k<=right && ft >= 0; k++) /* first test if blocked */
886 if(k != ft && board[0][k] != EmptySquare) ft = -1;
887 if(ff > BOARD_LEFT+2)
888 for(k=left+1; k<=right && ft >= 0; k++) /* then if not checked */
889 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = -1;
890 if(ft >= 0 && board[0][ft] == WhiteRook)
891 callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
894 ff = castlingRights[5]; /* King file if we have any rights */
895 if(ff > 0 && board[BOARD_HEIGHT-1][ff] == BlackKing) {
896 ft = castlingRights[3]; /* Rook file if we have H-side rights */
898 right = BOARD_RGHT-2;
899 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
900 for(k=left; k<=right && ft >= 0; k++) /* first test if blocked */
901 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = -1;
902 for(k=left; k<right && ft >= 0; k++) /* then if not checked */
903 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = -1;
904 if(ft >= 0 && board[BOARD_HEIGHT-1][ft] == BlackRook)
905 callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
907 ft = castlingRights[4]; /* Rook file if we have A-side rights */
910 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
911 for(k=left; k<=right && ft >= 0; k++) /* first test if blocked */
912 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = -1;
913 if(ff > BOARD_LEFT+2)
914 for(k=left+1; k<=right && ft >= 0; k++) /* then if not checked */
915 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = -1;
916 if(ft >= 0 && board[BOARD_HEIGHT-1][ft] == BlackRook)
917 callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
933 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
934 int rf, int ff, int rt, int ft,
938 void CheckTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
945 register CheckTestClosure *cl = (CheckTestClosure *) closure;
947 if (rt == cl->rking && ft == cl->fking) cl->check++;
951 /* If the player on move were to move from (rf, ff) to (rt, ft), would
952 he leave himself in check? Or if rf == -1, is the player on move
953 in check now? enPassant must be TRUE if the indicated move is an
954 e.p. capture. The possibility of castling out of a check along the
955 back rank is not accounted for (i.e., we still return nonzero), as
956 this is illegal anyway. Return value is the number of times the
958 int CheckTest(board, flags, rf, ff, rt, ft, enPassant)
961 int rf, ff, rt, ft, enPassant;
964 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
965 ChessSquare captured = EmptySquare;
966 /* Suppress warnings on uninitialized variables */
968 if(gameInfo.variant == VariantXiangqi)
969 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
970 if(gameInfo.variant == VariantKnightmate)
971 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
975 captured = board[rf][ft];
976 board[rf][ft] = EmptySquare;
978 captured = board[rt][ft];
980 board[rt][ft] = board[rf][ff];
981 board[rf][ff] = EmptySquare;
984 /* For compatibility with ICS wild 9, we scan the board in the
985 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
986 and we test only whether that one is in check. */
988 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
989 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
990 if (board[cl.rking][cl.fking] == king) {
991 if(gameInfo.variant == VariantXiangqi) {
992 /* [HGM] In Xiangqi opposing Kings means check as well */
994 dir = (king >= BlackPawn) ? -1 : 1;
995 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
996 board[i][cl.fking] == EmptySquare; i+=dir );
997 if(i>=0 && i<BOARD_HEIGHT &&
998 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1002 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, -1,
1003 CheckTestCallback, (VOIDSTAR) &cl);
1004 goto undo_move; /* 2-level break */
1011 board[rf][ff] = board[rt][ft];
1013 board[rf][ft] = captured;
1014 board[rt][ft] = EmptySquare;
1016 board[rt][ft] = captured;
1020 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1024 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1025 int rf, int ff, int rt, int ft,
1028 void LegalityTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1035 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1037 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1038 cl->captures++; // [HGM] losers: count legal captures
1039 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1043 ChessMove LegalityTest(board, flags, epfile, castlingRights, rf, ff, rt, ft, promoChar)
1046 int rf, ff, rt, ft, promoChar;
1047 char castlingRights[];
1049 LegalityTestClosure cl; ChessSquare piece = board[rf][ff];
1051 /* [HGM] Lance, Cobra and Falcon are wildcard pieces; consider all their moves legal */
1052 /* (perhaps we should disallow moves that obviously leave us in check?) */
1053 if(piece == WhiteFalcon || piece == BlackFalcon ||
1054 piece == WhiteCobra || piece == BlackCobra ||
1055 piece == WhiteLance || piece == BlackLance)
1056 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1062 cl.kind = IllegalMove;
1063 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1064 GenLegal(board, flags, epfile, castlingRights, LegalityTestCallback, (VOIDSTAR) &cl);
1065 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1066 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1067 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1069 if(gameInfo.variant == VariantShogi) {
1070 /* [HGM] Shogi promotions. '=' means defer */
1071 if(rf != DROP_RANK && cl.kind == NormalMove) {
1072 ChessSquare piece = board[rf][ff];
1074 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1075 if(promoChar != NULLCHAR && promoChar != 'x' &&
1076 promoChar != '+' && promoChar != '=' &&
1077 ToUpper(PieceToChar(PROMOTED piece)) != ToUpper(promoChar) )
1078 cl.kind = IllegalMove;
1079 else if(flags & F_WHITE_ON_MOVE) {
1080 if( (int) piece < (int) WhiteWazir &&
1081 (rf > BOARD_HEIGHT-4 || rt > BOARD_HEIGHT-4) ) {
1082 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1083 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1084 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotionKnight;
1085 else /* promotion optional, default is promote */
1086 cl.kind = promoChar == '=' ? NormalMove : WhitePromotionQueen;
1088 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1089 NormalMove : IllegalMove;
1091 if( (int) piece < (int) BlackWazir && (rf < 3 || rt < 3) ) {
1092 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1093 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1094 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotionKnight;
1095 else /* promotion optional, default is promote */
1096 cl.kind = promoChar == '=' ? NormalMove : BlackPromotionQueen;
1098 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1099 NormalMove : IllegalMove;
1103 if (promoChar != NULLCHAR && promoChar != 'x') {
1104 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1105 if (cl.kind == WhitePromotionQueen || cl.kind == BlackPromotionQueen) {
1107 PromoCharToMoveType((flags & F_WHITE_ON_MOVE) != 0, promoChar);
1109 cl.kind = IllegalMove;
1112 /* [HGM] For promotions, 'ToQueen' = optional, 'ToKnight' = mandatory */
1120 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1121 int rf, int ff, int rt, int ft,
1124 void MateTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1131 register MateTestClosure *cl = (MateTestClosure *) closure;
1136 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1137 int MateTest(board, flags, epfile, castlingRights)
1140 char castlingRights[];
1143 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1144 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1146 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1147 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1148 nrKing += (board[r][f] == king); // stm has king
1149 if( board[r][f] != EmptySquare ) {
1150 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1156 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1157 case VariantShatranj:
1158 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1162 if(nrKing == 0) return MT_NOKING;
1165 if(myPieces == 1) return MT_BARE;
1168 inCheck = GenLegal(board, flags, epfile, castlingRights, MateTestCallback, (VOIDSTAR) &cl);
1169 // [HGM] 3check: yet to do!
1171 return inCheck ? MT_CHECK : MT_NONE;
1173 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1174 return myPieces == hisPieces ? MT_STALEMATE :
1175 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1176 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1177 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1179 return inCheck ? MT_CHECKMATE
1180 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj) ?
1181 MT_STAINMATE : MT_STALEMATE;
1186 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1187 int rf, int ff, int rt, int ft,
1190 void DisambiguateCallback(board, flags, kind, rf, ff, rt, ft, closure)
1197 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1198 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1200 // [HGM] wild: for wild-card pieces rt and rf are dummies
1201 if(piece == WhiteFalcon || piece == BlackFalcon ||
1202 piece == WhiteCobra || piece == BlackCobra ||
1203 piece == WhiteLance || piece == BlackLance)
1206 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1207 || PieceToChar(board[rf][ff]) == '~'
1208 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1210 (cl->rfIn == -1 || cl->rfIn == rf) &&
1211 (cl->ffIn == -1 || cl->ffIn == ff) &&
1212 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1213 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1216 cl->piece = board[rf][ff];
1219 cl->rt = wildCard ? cl->rtIn : rt;
1220 cl->ft = wildCard ? cl->ftIn : ft;
1225 void Disambiguate(board, flags, epfile, closure)
1228 DisambiguateClosure *closure;
1230 int illegal = 0; char c = closure->promoCharIn;
1233 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1234 closure->kind = ImpossibleMove;
1236 GenLegal(board, flags, epfile, initialRights, DisambiguateCallback, (VOIDSTAR) closure);
1237 if (closure->count == 0) {
1238 /* See if it's an illegal move due to check */
1240 GenLegal(board, flags|F_IGNORE_CHECK, epfile, initialRights, DisambiguateCallback,
1241 (VOIDSTAR) closure);
1242 if (closure->count == 0) {
1243 /* No, it's not even that */
1248 if(gameInfo.variant == VariantShogi) {
1249 /* [HGM] Shogi promotions. '=' means defer */
1250 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
1251 ChessSquare piece = closure->piece;
1252 if(c != NULLCHAR && c != 'x' && c != '+' && c != '=' &&
1253 ToUpper(PieceToChar(PROMOTED piece)) != ToUpper(c) )
1254 closure->kind = IllegalMove;
1255 else if(flags & F_WHITE_ON_MOVE) {
1256 if( (int) piece < (int) WhiteWazir &&
1257 (closure->rf > BOARD_HEIGHT-4 || closure->rt > BOARD_HEIGHT-4) ) {
1258 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
1259 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
1260 closure->kind = c == '=' ? IllegalMove : WhitePromotionKnight;
1261 else /* promotion optional, default is promote */
1262 closure->kind = c == '=' ? NormalMove : WhitePromotionQueen;
1264 } else closure->kind = (c == NULLCHAR || c == 'x' || c == '=') ?
1265 NormalMove : IllegalMove;
1267 if( (int) piece < (int) BlackWazir && (closure->rf < 3 || closure->rt < 3) ) {
1268 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
1269 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
1270 closure->kind = c == '=' ? IllegalMove : BlackPromotionKnight;
1271 else /* promotion optional, default is promote */
1272 closure->kind = c == '=' ? NormalMove : BlackPromotionQueen;
1274 } else closure->kind = (c == NULLCHAR || c == 'x' || c == '=') ?
1275 NormalMove : IllegalMove;
1279 if (closure->promoCharIn != NULLCHAR && closure->promoCharIn != 'x') {
1280 if (closure->kind == WhitePromotionQueen
1281 || closure->kind == BlackPromotionQueen) {
1283 PromoCharToMoveType((flags & F_WHITE_ON_MOVE) != 0,
1284 closure->promoCharIn);
1286 closure->kind = IllegalMove;
1289 /* [HGM] returns 'q' for optional promotion, 'n' for mandatory */
1290 if(closure->promoCharIn != '=')
1291 closure->promoChar = ToLower(closure->promoCharIn);
1292 else closure->promoChar = '=';
1293 if (closure->promoChar == 'x') closure->promoChar = NULLCHAR;
1294 if (closure->count > 1) {
1295 closure->kind = AmbiguousMove;
1298 /* Note: If more than one illegal move matches, but no legal
1299 moves, we return IllegalMove, not AmbiguousMove. Caller
1300 can look at closure->count to detect this.
1302 closure->kind = IllegalMove;
1304 if(closure->kind == IllegalMove)
1305 /* [HGM] might be a variant we don't understand, pass on promotion info */
1306 closure->promoChar = ToLower(closure->promoCharIn);
1319 } CoordsToAlgebraicClosure;
1321 extern void CoordsToAlgebraicCallback P((Board board, int flags,
1322 ChessMove kind, int rf, int ff,
1323 int rt, int ft, VOIDSTAR closure));
1325 void CoordsToAlgebraicCallback(board, flags, kind, rf, ff, rt, ft, closure)
1332 register CoordsToAlgebraicClosure *cl =
1333 (CoordsToAlgebraicClosure *) closure;
1335 if (rt == cl->rt && ft == cl->ft &&
1336 (board[rf][ff] == cl->piece
1337 || PieceToChar(board[rf][ff]) == '~' &&
1338 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
1342 cl->kind = kind; /* this is the move we want */
1344 cl->file++; /* need file to rule out this move */
1348 cl->rank++; /* need rank to rule out this move */
1350 cl->either++; /* rank or file will rule out this move */
1356 /* Convert coordinates to normal algebraic notation.
1357 promoChar must be NULLCHAR or 'x' if not a promotion.
1359 ChessMove CoordsToAlgebraic(board, flags, epfile,
1360 rf, ff, rt, ft, promoChar, out)
1369 char *outp = out, c;
1370 CoordsToAlgebraicClosure cl;
1372 if (rf == DROP_RANK) {
1373 /* Bughouse piece drop */
1374 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
1379 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1381 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
1384 if (promoChar == 'x') promoChar = NULLCHAR;
1385 piece = board[rf][ff];
1386 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
1391 kind = LegalityTest(board, flags, epfile, initialRights, rf, ff, rt, ft, promoChar);
1392 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1393 /* Keep short notation if move is illegal only because it
1394 leaves the player in check, but still return IllegalMove */
1395 kind = LegalityTest(board, flags|F_IGNORE_CHECK, epfile, initialRights,
1396 rf, ff, rt, ft, promoChar);
1397 if (kind == IllegalMove) break;
1402 if (ff == ft && board[rt][ft] == EmptySquare) { /* [HGM] Xiangqi has straight noncapts! */
1403 /* Non-capture; use style "e5" */
1406 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1408 /* Capture; use style "exd5" */
1409 if(gameInfo.variant != VariantXiangqi || board[rt][ft] != EmptySquare )
1410 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
1414 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1416 /* Use promotion suffix style "=Q" */
1418 if (promoChar != NULLCHAR) {
1419 if(gameInfo.variant == VariantShogi) {
1420 /* [HGM] ... but not in Shogi! */
1421 *outp++ = promoChar == '=' ? '=' : '+';
1424 *outp++ = ToUpper(promoChar);
1433 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
1434 /* Code added by Tord: FRC castling. */
1435 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
1436 (piece == BlackKing && board[rt][ft] == BlackRook)) {
1437 if(ft > ff) strcpy(out, "O-O"); else strcpy(out, "O-O-O");
1438 return LegalityTest(board, flags, epfile, initialRights,
1439 rf, ff, rt, ft, promoChar);
1441 /* End of code added by Tord */
1442 /* Test for castling or ICS wild castling */
1443 /* Use style "O-O" (oh-oh) for PGN compatibility */
1444 else if (rf == rt &&
1445 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
1446 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
1447 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
1448 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
1451 strcpy(out, "O-O-O");
1453 /* This notation is always unambiguous, unless there are
1454 kings on both the d and e files, with "wild castling"
1455 possible for the king on the d file and normal castling
1456 possible for the other. ICS rules for wild 9
1457 effectively make castling illegal for either king in
1458 this situation. So I am not going to worry about it;
1459 I'll just generate an ambiguous O-O in this case.
1461 return LegalityTest(board, flags, epfile, initialRights,
1462 rf, ff, rt, ft, promoChar);
1465 /* else fall through */
1473 cl.kind = IllegalMove;
1474 cl.rank = cl.file = cl.either = 0;
1475 GenLegal(board, flags, epfile, initialRights,
1476 CoordsToAlgebraicCallback, (VOIDSTAR) &cl);
1478 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1479 /* Generate pretty moves for moving into check, but
1480 still return IllegalMove.
1482 GenLegal(board, flags|F_IGNORE_CHECK, epfile, initialRights,
1483 CoordsToAlgebraicCallback, (VOIDSTAR) &cl);
1484 if (cl.kind == IllegalMove) break;
1485 cl.kind = IllegalMove;
1488 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
1489 else "Ngf3" or "Ngxf7",
1490 else "N1f3" or "N5xf7",
1491 else "Ng1f3" or "Ng5xf7".
1493 c = PieceToChar(piece) ;
1494 if( c == '~' || c == '+') {
1495 /* [HGM] print nonexistent piece as its demoted version */
1496 piece = (ChessSquare) (DEMOTED piece);
1498 if(c=='+') *outp++ = c;
1499 *outp++ = ToUpper(PieceToChar(piece));
1501 if (cl.file || (cl.either && !cl.rank)) {
1507 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1510 if(board[rt][ft] != EmptySquare)
1516 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1518 if (gameInfo.variant == VariantShogi) {
1519 /* [HGM] in Shogi non-pawns can promote */
1520 if(flags & F_WHITE_ON_MOVE) {
1521 if( (int) cl.piece < (int) WhiteWazir &&
1522 (rf > BOARD_HEIGHT-4 || rt > BOARD_HEIGHT-4) ) {
1523 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1524 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1525 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotionKnight;
1526 else cl.kind = WhitePromotionQueen; /* promotion optional */
1528 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1529 NormalMove : IllegalMove;
1531 if( (int) cl.piece < (int) BlackWazir && (rf < 3 || rt < 3) ) {
1532 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1533 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1534 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotionKnight;
1535 else cl.kind = BlackPromotionQueen; /* promotion optional */
1536 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1537 NormalMove : IllegalMove;
1539 if(cl.kind == WhitePromotionQueen || cl.kind == BlackPromotionQueen) {
1540 /* for optional promotions append '+' or '=' */
1541 if(promoChar == '=') {
1543 cl.kind = NormalMove;
1544 } else *outp++ = '+';
1546 } else if(cl.kind == IllegalMove) {
1547 /* Illegal move specifies any given promotion */
1548 if(promoChar != NULLCHAR && promoChar != 'x') {
1550 *outp++ = ToUpper(promoChar);
1557 /* [HGM] Always long notation for fairies we don't know */
1562 case WhiteGrasshopper:
1563 case BlackGrasshopper:
1565 /* Moving a nonexistent piece */
1569 /* Not a legal move, even ignoring check.
1570 If there was a piece on the from square,
1571 use style "Ng1g3" or "Ng1xe8";
1572 if there was a pawn or nothing (!),
1573 use style "g1g3" or "g1xe8". Use "x"
1574 if a piece was on the to square, even
1575 a piece of the same color.
1578 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
1579 *outp++ = ToUpper(PieceToChar(piece));
1584 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1585 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
1589 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1590 /* Use promotion suffix style "=Q" */
1591 if (promoChar != NULLCHAR && promoChar != 'x') {
1593 *outp++ = ToUpper(promoChar);
1600 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
1609 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
1611 int preyStackPointer, chaseStackPointer;
1614 char rf, ff, rt, ft;
1624 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
1626 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
1627 int rf, int ff, int rt, int ft,
1630 void AttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1636 { // For adding captures that can lead to chase indictment to the chaseStack
1637 if(board[rt][ft] == EmptySquare) return; // non-capture
1638 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
1639 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
1640 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
1641 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
1642 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
1643 chaseStack[chaseStackPointer].rf = rf;
1644 chaseStack[chaseStackPointer].ff = ff;
1645 chaseStack[chaseStackPointer].rt = rt;
1646 chaseStack[chaseStackPointer].ft = ft;
1647 chaseStackPointer++;
1650 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
1651 int rf, int ff, int rt, int ft,
1654 void ExistingAttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1660 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
1662 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
1664 if(board[rt][ft] == EmptySquare) return; // no capture
1665 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
1666 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
1668 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
1669 for(i=0; i<chaseStackPointer; i++) {
1670 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
1671 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
1672 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
1673 chaseStack[i] = chaseStack[--chaseStackPointer];
1679 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
1680 int rf, int ff, int rt, int ft,
1683 void ProtectedCallback(board, flags, kind, rf, ff, rt, ft, closure)
1689 { // for determining if a piece (given through the closure) is protected
1690 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
1692 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
1693 if(appData.debugMode && board[rt][ft] != EmptySquare)
1694 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
1697 extern char moveList[MAX_MOVES][MOVE_LEN];
1699 int PerpetualChase(int first, int last)
1700 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
1703 ChessSquare captured;
1705 preyStackPointer = 0; // clear stack of chased pieces
1706 for(i=first; i<last; i+=2) { // for all positions with same side to move
1707 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
1708 chaseStackPointer = 0; // clear stack that is going to hold possible chases
1709 // determine all captures possible after the move, and put them on chaseStack
1710 GenLegal(boards[i+1], PosFlags(i), EP_NONE, initialRights, AttacksCallback, &cl);
1711 if(appData.debugMode) { int n;
1712 for(n=0; n<chaseStackPointer; n++)
1713 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1714 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1715 fprintf(debugFP, ": all capts\n");
1717 // determine all captures possible before the move, and delete them from chaseStack
1718 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
1719 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
1720 cl.rt = moveList[i][3]-ONE;
1721 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
1722 GenLegal(boards[i], PosFlags(i), EP_NONE, initialRights, ExistingAttacksCallback, &cl);
1723 if(appData.debugMode) { int n;
1724 for(n=0; n<chaseStackPointer; n++)
1725 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1726 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1727 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
1729 // chaseSack now contains all captures made possible by the move
1730 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
1731 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1732 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1734 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
1735 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
1737 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
1738 continue; // C or H attack on R is always chase; leave on chaseStack
1740 if(attacker == victim) {
1741 if(LegalityTest(boards[i+1], PosFlags(i+1), EP_NONE, initialRights, chaseStack[j].rt,
1742 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
1743 // we can capture back with equal piece, so this is no chase but a sacrifice
1744 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
1745 j--; /* ! */ continue;
1750 // the attack is on a lower piece, or on a pinned or blocked equal one
1751 // test if the victim is protected by a true protector. First make the capture.
1752 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1753 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1754 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
1755 // Then test if the opponent can recapture
1756 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
1757 cl.rt = chaseStack[j].rt;
1758 cl.ft = chaseStack[j].ft;
1759 if(appData.debugMode) {
1760 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
1762 GenLegal(boards[i+1], PosFlags(i+1), EP_NONE, initialRights, ProtectedCallback, &cl); // try all moves
1763 // unmake the capture
1764 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1765 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
1766 // if a recapture was found, piece is protected, and we are not chasing it.
1767 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
1768 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
1772 // chaseStack now contains all moves that chased
1773 if(appData.debugMode) { int n;
1774 for(n=0; n<chaseStackPointer; n++)
1775 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1776 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1777 fprintf(debugFP, ": chases\n");
1779 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
1780 for(j=0; j<chaseStackPointer; j++) {
1781 preyStack[j].rank = chaseStack[j].rt;
1782 preyStack[j].file = chaseStack[j].ft;
1784 preyStackPointer = chaseStackPointer;
1787 for(j=0; j<chaseStackPointer; j++) {
1788 for(k=0; k<preyStackPointer; k++) {
1789 // search the victim of each chase move on the preyStack (first occurrence)
1790 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
1791 if(k < tail) break; // piece was already identified as still being chased
1792 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
1793 preyStack[tail] = preyStack[k]; // by swapping
1794 preyStack[k] = preyStack[preyStackPointer];
1800 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
1801 if(appData.debugMode) { int n;
1802 for(n=0; n<preyStackPointer; n++)
1803 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
1804 fprintf(debugFP, "always chased upto ply %d\n", i);
1806 // now adjust the location of the chased pieces according to opponent move
1807 for(j=0; j<preyStackPointer; j++) {
1808 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
1809 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
1810 preyStack[j].rank = moveList[i+1][3]-ONE;
1811 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
1816 return preyStackPointer; // if any piece was left on preyStack, it has been perpetually chased