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_FILES]; /* [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];
230 for (j = 0; j < BOARD_FILES-1; j++) // [HGM] gamestate: copy castling rights and ep status
231 to[CASTLING][j] = from[CASTLING][j];
232 to[HOLDINGS_SET] = 0; // flag used in ICS play
235 int CompareBoards(board1, board2)
236 Board board1, board2;
240 for (i = 0; i < BOARD_HEIGHT; i++)
241 for (j = 0; j < BOARD_WIDTH; j++) {
242 if (board1[i][j] != board2[i][j])
249 /* Call callback once for each pseudo-legal move in the given
250 position, except castling moves. A move is pseudo-legal if it is
251 legal, or if it would be legal except that it leaves the king in
252 check. In the arguments, epfile is EP_NONE if the previous move
253 was not a double pawn push, or the file 0..7 if it was, or
254 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
255 Promotion moves generated are to Queen only.
257 void GenPseudoLegal(board, flags, callback, closure)
260 MoveCallback callback;
264 int i, j, d, s, fs, rs, rt, ft, m;
265 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
267 for (rf = 0; rf < BOARD_HEIGHT; rf++)
268 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
271 if (flags & F_WHITE_ON_MOVE) {
272 if (!WhitePiece(board[rf][ff])) continue;
274 if (!BlackPiece(board[rf][ff])) continue;
276 m = 0; piece = board[rf][ff];
277 if(PieceToChar(piece) == '~')
278 piece = (ChessSquare) ( DEMOTED piece );
279 if(gameInfo.variant == VariantShogi)
280 piece = (ChessSquare) ( SHOGI piece );
283 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
285 /* can't happen ([HGM] except for faries...) */
289 if(gameInfo.variant == VariantXiangqi) {
290 /* [HGM] capture and move straight ahead in Xiangqi */
291 if (rf < BOARD_HEIGHT-1 &&
292 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
293 callback(board, flags, NormalMove,
294 rf, ff, rf + 1, ff, closure);
296 /* and move sideways when across the river */
297 for (s = -1; s <= 1; s += 2) {
298 if (rf >= BOARD_HEIGHT>>1 &&
299 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
300 !WhitePiece(board[rf][ff+s]) ) {
301 callback(board, flags, NormalMove,
302 rf, ff, rf, ff+s, closure);
307 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
308 callback(board, flags,
309 rf == BOARD_HEIGHT-2 ? WhitePromotionQueen : NormalMove,
310 rf, ff, rf + 1, ff, closure);
312 if (rf == 1 && board[2][ff] == EmptySquare &&
313 gameInfo.variant != VariantShatranj && /* [HGM] */
314 gameInfo.variant != VariantCourier && /* [HGM] */
315 board[3][ff] == EmptySquare ) {
316 callback(board, flags, NormalMove,
317 rf, ff, 3, ff, closure);
319 for (s = -1; s <= 1; s += 2) {
320 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
321 ((flags & F_KRIEGSPIEL_CAPTURE) ||
322 BlackPiece(board[rf + 1][ff + s]))) {
323 callback(board, flags,
324 rf == BOARD_HEIGHT-2 ? WhitePromotionQueen : NormalMove,
325 rf, ff, rf + 1, ff + s, closure);
327 if (rf == BOARD_HEIGHT-4) {
328 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
329 (epfile == ff + s || epfile == EP_UNKNOWN) &&
330 board[BOARD_HEIGHT-4][ff + s] == BlackPawn &&
331 board[BOARD_HEIGHT-3][ff + s] == EmptySquare) {
332 callback(board, flags, WhiteCapturesEnPassant,
333 rf, ff, 5, ff + s, closure);
340 if(gameInfo.variant == VariantXiangqi) {
341 /* [HGM] capture straight ahead in Xiangqi */
342 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
343 callback(board, flags, NormalMove,
344 rf, ff, rf - 1, ff, closure);
346 /* and move sideways when across the river */
347 for (s = -1; s <= 1; s += 2) {
348 if (rf < BOARD_HEIGHT>>1 &&
349 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
350 !BlackPiece(board[rf][ff+s]) ) {
351 callback(board, flags, NormalMove,
352 rf, ff, rf, ff+s, closure);
357 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
358 callback(board, flags,
359 rf == 1 ? BlackPromotionQueen : NormalMove,
360 rf, ff, rf - 1, ff, closure);
362 if (rf == BOARD_HEIGHT-2 && board[BOARD_HEIGHT-3][ff] == EmptySquare &&
363 gameInfo.variant != VariantShatranj && /* [HGM] */
364 gameInfo.variant != VariantCourier && /* [HGM] */
365 board[BOARD_HEIGHT-4][ff] == EmptySquare) {
366 callback(board, flags, NormalMove,
367 rf, ff, BOARD_HEIGHT-4, ff, closure);
369 for (s = -1; s <= 1; s += 2) {
370 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
371 ((flags & F_KRIEGSPIEL_CAPTURE) ||
372 WhitePiece(board[rf - 1][ff + s]))) {
373 callback(board, flags,
374 rf == 1 ? BlackPromotionQueen : NormalMove,
375 rf, ff, rf - 1, ff + s, closure);
378 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
379 (epfile == ff + s || epfile == EP_UNKNOWN) &&
380 board[3][ff + s] == WhitePawn &&
381 board[2][ff + s] == EmptySquare) {
382 callback(board, flags, BlackCapturesEnPassant,
383 rf, ff, 2, ff + s, closure);
394 for (i = -1; i <= 1; i += 2)
395 for (j = -1; j <= 1; j += 2)
396 for (s = 1; s <= 2; s++) {
399 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
400 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
401 && !SameColor(board[rf][ff], board[rt][ft]))
402 callback(board, flags, NormalMove,
403 rf, ff, rt, ft, closure);
407 case SHOGI WhiteKnight:
408 for (s = -1; s <= 1; s += 2) {
409 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
410 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
411 callback(board, flags, NormalMove,
412 rf, ff, rf + 2, ff + s, closure);
417 case SHOGI BlackKnight:
418 for (s = -1; s <= 1; s += 2) {
419 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
420 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
421 callback(board, flags, NormalMove,
422 rf, ff, rf - 2, ff + s, closure);
429 for (d = 0; d <= 1; d++)
430 for (s = -1; s <= 1; s += 2) {
433 rt = rf + (i * s) * d;
434 ft = ff + (i * s) * (1 - d);
435 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
436 if (m == 0 && board[rt][ft] == EmptySquare)
437 callback(board, flags, NormalMove,
438 rf, ff, rt, ft, closure);
439 if (m == 1 && board[rt][ft] != EmptySquare &&
440 !SameColor(board[rf][ff], board[rt][ft]) )
441 callback(board, flags, NormalMove,
442 rf, ff, rt, ft, closure);
443 if (board[rt][ft] != EmptySquare && m++) break;
448 /* Gold General (and all its promoted versions) . First do the */
449 /* diagonal forward steps, then proceed as normal Wazir */
450 case SHOGI WhiteWazir:
451 case SHOGI (PROMOTED WhitePawn):
452 case SHOGI (PROMOTED WhiteKnight):
453 case SHOGI (PROMOTED WhiteQueen):
454 case SHOGI (PROMOTED WhiteFerz):
455 for (s = -1; s <= 1; s += 2) {
456 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
457 !SameColor(board[rf][ff], board[rf + 1][ff + s])) {
458 callback(board, flags, NormalMove,
459 rf, ff, rf + 1, ff + s, closure);
464 case SHOGI BlackWazir:
465 case SHOGI (PROMOTED BlackPawn):
466 case SHOGI (PROMOTED BlackKnight):
467 case SHOGI (PROMOTED BlackQueen):
468 case SHOGI (PROMOTED BlackFerz):
469 for (s = -1; s <= 1; s += 2) {
470 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
471 !SameColor(board[rf][ff], board[rf - 1][ff + s])) {
472 callback(board, flags, NormalMove,
473 rf, ff, rf - 1, ff + s, closure);
480 for (d = 0; d <= 1; d++)
481 for (s = -1; s <= 1; s += 2) {
483 ft = ff + s * (1 - d);
484 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
485 && !SameColor(board[rf][ff], board[rt][ft]) &&
486 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
487 callback(board, flags, NormalMove,
488 rf, ff, rt, ft, closure);
494 /* [HGM] support Shatranj pieces */
495 for (rs = -1; rs <= 1; rs += 2)
496 for (fs = -1; fs <= 1; fs += 2) {
499 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
500 && ( gameInfo.variant != VariantXiangqi ||
501 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
503 && !SameColor(board[rf][ff], board[rt][ft]))
504 callback(board, flags, NormalMove,
505 rf, ff, rt, ft, closure);
509 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
510 case SHOGI WhiteCardinal:
511 case SHOGI BlackCardinal:
514 /* Capablanca Archbishop continues as Knight */
519 /* Shogi Bishops are ordinary Bishops */
520 case SHOGI WhiteBishop:
521 case SHOGI BlackBishop:
524 for (rs = -1; rs <= 1; rs += 2)
525 for (fs = -1; fs <= 1; fs += 2)
529 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
530 if (SameColor(board[rf][ff], board[rt][ft])) break;
531 callback(board, flags, NormalMove,
532 rf, ff, rt, ft, closure);
533 if (board[rt][ft] != EmptySquare) break;
535 if(m==1) goto mounted;
536 if(m==2) goto finishGold;
537 /* Bishop falls through */
540 /* Shogi Lance is unlike anything, and asymmetric at that */
541 case SHOGI WhiteQueen:
545 if (rt >= BOARD_HEIGHT) break;
546 if (SameColor(board[rf][ff], board[rt][ft])) break;
547 callback(board, flags, NormalMove,
548 rf, ff, rt, ft, closure);
549 if (board[rt][ft] != EmptySquare) break;
553 case SHOGI BlackQueen:
558 if (SameColor(board[rf][ff], board[rt][ft])) break;
559 callback(board, flags, NormalMove,
560 rf, ff, rt, ft, closure);
561 if (board[rt][ft] != EmptySquare) break;
565 /* Shogi Dragon King has to continue as Ferz after Rook moves */
566 case SHOGI WhiteDragon:
567 case SHOGI BlackDragon:
570 /* Capablanca Chancellor sets flag to continue as Knight */
575 /* Shogi Rooks are ordinary Rooks */
576 case SHOGI WhiteRook:
577 case SHOGI BlackRook:
580 for (d = 0; d <= 1; d++)
581 for (s = -1; s <= 1; s += 2)
583 rt = rf + (i * s) * d;
584 ft = ff + (i * s) * (1 - d);
585 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
586 if (SameColor(board[rf][ff], board[rt][ft])) break;
587 callback(board, flags, NormalMove,
588 rf, ff, rt, ft, closure);
589 if (board[rt][ft] != EmptySquare) break;
591 if(m==1) goto mounted;
592 if(m==2) goto finishSilver;
597 for (rs = -1; rs <= 1; rs++)
598 for (fs = -1; fs <= 1; fs++) {
599 if (rs == 0 && fs == 0) continue;
603 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
604 if (SameColor(board[rf][ff], board[rt][ft])) break;
605 callback(board, flags, NormalMove,
606 rf, ff, rt, ft, closure);
607 if (board[rt][ft] != EmptySquare) break;
612 /* Shogi Pawn and Silver General: first the Pawn move, */
613 /* then the General continues like a Ferz */
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;
623 case SHOGI BlackPawn:
624 case SHOGI BlackFerz:
626 !SameColor(board[rf][ff], board[rf - 1][ff]) )
627 callback(board, flags, NormalMove,
628 rf, ff, rf - 1, ff, closure);
629 if(piece == SHOGI BlackPawn) break;
634 /* [HGM] support Shatranj pieces */
635 for (rs = -1; rs <= 1; rs += 2)
636 for (fs = -1; fs <= 1; fs += 2) {
639 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
640 if (!SameColor(board[rf][ff], board[rt][ft]) &&
641 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
642 callback(board, flags, NormalMove,
643 rf, ff, rt, ft, closure);
649 m++; // [HGM] superchess: use for Centaur
652 case SHOGI WhiteKing:
653 case SHOGI BlackKing:
657 for (i = -1; i <= 1; i++)
658 for (j = -1; j <= 1; j++) {
659 if (i == 0 && j == 0) continue;
662 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
663 if (SameColor(board[rf][ff], board[rt][ft])) continue;
664 callback(board, flags, NormalMove,
665 rf, ff, rt, ft, closure);
667 if(m==1) goto mounted;
670 case WhiteNightrider:
671 case BlackNightrider:
672 for (i = -1; i <= 1; i += 2)
673 for (j = -1; j <= 1; j += 2)
674 for (s = 1; s <= 2; s++) { int k;
678 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
679 if (SameColor(board[rf][ff], board[rt][ft])) break;
680 callback(board, flags, NormalMove,
681 rf, ff, rt, ft, closure);
682 if (board[rt][ft] != EmptySquare) break;
686 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
692 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
705 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
706 int rf, int ff, int rt, int ft,
709 void GenLegalCallback(board, flags, kind, rf, ff, rt, ft, closure)
716 register GenLegalClosure *cl = (GenLegalClosure *) closure;
718 if (!(flags & F_IGNORE_CHECK) &&
719 CheckTest(board, flags, rf, ff, rt, ft,
720 kind == WhiteCapturesEnPassant ||
721 kind == BlackCapturesEnPassant)) return;
722 if (flags & F_ATOMIC_CAPTURE) {
723 if (board[rt][ft] != EmptySquare ||
724 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
726 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
727 if (board[rf][ff] == king) return;
728 for (r = rt-1; r <= rt+1; r++) {
729 for (f = ft-1; f <= ft+1; f++) {
730 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
731 board[r][f] == king) return;
736 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
743 int captures; // [HGM] losers
744 } LegalityTestClosure;
747 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
748 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
749 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
750 moves that would destroy your own king. The CASTLE_OK flags are
751 true if castling is not yet ruled out by a move of the king or
752 rook. Return TRUE if the player on move is currently in check and
753 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
754 int GenLegal(board, flags, callback, closure)
757 MoveCallback callback;
761 int ff, ft, k, left, right;
762 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
763 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
767 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl);
770 CheckTest(board, flags, -1, -1, -1, -1, FALSE)) return TRUE;
772 /* Generate castling moves */
773 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
774 wKing = WhiteUnicorn; bKing = BlackUnicorn;
777 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
778 if ((flags & F_WHITE_ON_MOVE) &&
779 (flags & F_WHITE_KCASTLE_OK) &&
780 board[0][ff] == wKing &&
781 board[0][ff + 1] == EmptySquare &&
782 board[0][ff + 2] == EmptySquare &&
783 board[0][BOARD_RGHT-3] == EmptySquare &&
784 board[0][BOARD_RGHT-2] == EmptySquare &&
785 board[0][BOARD_RGHT-1] == WhiteRook &&
786 castlingRights[0] != NoRights && /* [HGM] check rights */
787 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
789 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
790 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
791 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
792 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
794 callback(board, flags,
795 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
796 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
798 if ((flags & F_WHITE_ON_MOVE) &&
799 (flags & F_WHITE_QCASTLE_OK) &&
800 board[0][ff] == wKing &&
801 board[0][ff - 1] == EmptySquare &&
802 board[0][ff - 2] == EmptySquare &&
803 board[0][BOARD_LEFT+2] == EmptySquare &&
804 board[0][BOARD_LEFT+1] == EmptySquare &&
805 board[0][BOARD_LEFT+0] == WhiteRook &&
806 castlingRights[1] != NoRights && /* [HGM] check rights */
807 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
809 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
810 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
811 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
813 callback(board, flags,
814 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
815 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
817 if (!(flags & F_WHITE_ON_MOVE) &&
818 (flags & F_BLACK_KCASTLE_OK) &&
819 board[BOARD_HEIGHT-1][ff] == bKing &&
820 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
821 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
822 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
823 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
824 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
825 castlingRights[3] != NoRights && /* [HGM] check rights */
826 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
828 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
829 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
830 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
831 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
833 callback(board, flags,
834 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
835 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
837 if (!(flags & F_WHITE_ON_MOVE) &&
838 (flags & F_BLACK_QCASTLE_OK) &&
839 board[BOARD_HEIGHT-1][ff] == bKing &&
840 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
841 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
842 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
843 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
844 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
845 castlingRights[4] != NoRights && /* [HGM] check rights */
846 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
848 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
849 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
850 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
852 callback(board, flags,
853 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
854 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
858 if(flags & F_FRC_TYPE_CASTLING) {
860 /* generate all potential FRC castling moves (KxR), ignoring flags */
861 /* [HGM] test if the Rooks we find have castling rights */
864 if ((flags & F_WHITE_ON_MOVE) != 0) {
865 ff = castlingRights[2]; /* King file if we have any rights */
866 if(ff != NoRights && board[0][ff] == WhiteKing) {
867 if (appData.debugMode) {
868 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
869 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
871 ft = castlingRights[0]; /* Rook file if we have H-side rights */
873 right = BOARD_RGHT-2;
874 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
875 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
876 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
877 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
878 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
879 if(ft != NoRights && board[0][ft] == WhiteRook)
880 callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
882 ft = castlingRights[1]; /* Rook file if we have A-side rights */
885 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
886 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
887 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
888 if(ff > BOARD_LEFT+2)
889 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
890 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
891 if(ft != NoRights && board[0][ft] == WhiteRook)
892 callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
895 ff = castlingRights[5]; /* King file if we have any rights */
896 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
897 ft = castlingRights[3]; /* Rook file if we have H-side rights */
899 right = BOARD_RGHT-2;
900 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
901 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
902 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
903 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
904 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
905 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
906 callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
908 ft = castlingRights[4]; /* Rook file if we have A-side rights */
911 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
912 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
913 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
914 if(ff > BOARD_LEFT+2)
915 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
916 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
917 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
918 callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
934 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
935 int rf, int ff, int rt, int ft,
939 void CheckTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
946 register CheckTestClosure *cl = (CheckTestClosure *) closure;
948 if (rt == cl->rking && ft == cl->fking) cl->check++;
952 /* If the player on move were to move from (rf, ff) to (rt, ft), would
953 he leave himself in check? Or if rf == -1, is the player on move
954 in check now? enPassant must be TRUE if the indicated move is an
955 e.p. capture. The possibility of castling out of a check along the
956 back rank is not accounted for (i.e., we still return nonzero), as
957 this is illegal anyway. Return value is the number of times the
959 int CheckTest(board, flags, rf, ff, rt, ft, enPassant)
962 int rf, ff, rt, ft, enPassant;
965 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
966 ChessSquare captured = EmptySquare;
967 /* Suppress warnings on uninitialized variables */
969 if(gameInfo.variant == VariantXiangqi)
970 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
971 if(gameInfo.variant == VariantKnightmate)
972 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
976 captured = board[rf][ft];
977 board[rf][ft] = EmptySquare;
979 captured = board[rt][ft];
981 board[rt][ft] = board[rf][ff];
982 board[rf][ff] = EmptySquare;
985 /* For compatibility with ICS wild 9, we scan the board in the
986 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
987 and we test only whether that one is in check. */
989 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
990 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
991 if (board[cl.rking][cl.fking] == king) {
992 if(gameInfo.variant == VariantXiangqi) {
993 /* [HGM] In Xiangqi opposing Kings means check as well */
995 dir = (king >= BlackPawn) ? -1 : 1;
996 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
997 board[i][cl.fking] == EmptySquare; i+=dir );
998 if(i>=0 && i<BOARD_HEIGHT &&
999 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1003 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, 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 (appData.debugMode) {
1038 // fprintf(debugFP, "Legality test: %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
1040 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1041 cl->captures++; // [HGM] losers: count legal captures
1042 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1046 ChessMove LegalityTest(board, flags, rf, ff, rt, ft, promoChar)
1049 int rf, ff, rt, ft, promoChar;
1051 LegalityTestClosure cl; ChessSquare piece = board[rf][ff], *castlingRights = board[CASTLING];
1053 if (appData.debugMode) {
1055 for(i=0; i<6; i++) fprintf(debugFP, "%d ", castlingRights[i]);
1056 fprintf(debugFP, "Legality test? %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
1058 /* [HGM] Lance, Cobra and Falcon are wildcard pieces; consider all their moves legal */
1059 /* (perhaps we should disallow moves that obviously leave us in check?) */
1060 if(piece == WhiteFalcon || piece == BlackFalcon ||
1061 piece == WhiteCobra || piece == BlackCobra ||
1062 piece == WhiteLance || piece == BlackLance)
1063 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1069 cl.kind = IllegalMove;
1070 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1071 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl);
1072 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1073 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1074 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1076 if(gameInfo.variant == VariantShogi) {
1077 /* [HGM] Shogi promotions. '=' means defer */
1078 if(rf != DROP_RANK && cl.kind == NormalMove) {
1079 ChessSquare piece = board[rf][ff];
1081 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1082 if(promoChar != NULLCHAR && promoChar != 'x' &&
1083 promoChar != '+' && promoChar != '=' &&
1084 ToUpper(PieceToChar(PROMOTED piece)) != ToUpper(promoChar) )
1085 cl.kind = IllegalMove;
1086 else if(flags & F_WHITE_ON_MOVE) {
1087 if( (int) piece < (int) WhiteWazir &&
1088 (rf > BOARD_HEIGHT-4 || rt > BOARD_HEIGHT-4) ) {
1089 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1090 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1091 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotionKnight;
1092 else /* promotion optional, default is promote */
1093 cl.kind = promoChar == '=' ? NormalMove : WhitePromotionQueen;
1095 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1096 NormalMove : IllegalMove;
1098 if( (int) piece < (int) BlackWazir && (rf < 3 || rt < 3) ) {
1099 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1100 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1101 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotionKnight;
1102 else /* promotion optional, default is promote */
1103 cl.kind = promoChar == '=' ? NormalMove : BlackPromotionQueen;
1105 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1106 NormalMove : IllegalMove;
1110 if (promoChar != NULLCHAR && promoChar != 'x') {
1111 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1112 if (cl.kind == WhitePromotionQueen || cl.kind == BlackPromotionQueen) {
1114 PromoCharToMoveType((flags & F_WHITE_ON_MOVE) != 0, promoChar);
1116 cl.kind = IllegalMove;
1119 /* [HGM] For promotions, 'ToQueen' = optional, 'ToKnight' = mandatory */
1127 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1128 int rf, int ff, int rt, int ft,
1131 void MateTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1138 register MateTestClosure *cl = (MateTestClosure *) closure;
1143 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1144 int MateTest(board, flags)
1149 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1150 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1152 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1153 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1154 nrKing += (board[r][f] == king); // stm has king
1155 if( board[r][f] != EmptySquare ) {
1156 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1161 if(appData.debugMode) fprintf(debugFP, "MateTest: K=%d, my=%d, his=%d\n", nrKing, myPieces, hisPieces);
1162 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1163 case VariantShatranj:
1164 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1168 if(nrKing == 0) return MT_NOKING;
1171 if(myPieces == 1) return MT_BARE;
1174 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl);
1175 // [HGM] 3check: yet to do!
1177 return inCheck ? MT_CHECK : MT_NONE;
1179 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1180 return myPieces == hisPieces ? MT_STALEMATE :
1181 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1182 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1183 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1185 return inCheck ? MT_CHECKMATE
1186 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj) ?
1187 MT_STAINMATE : MT_STALEMATE;
1192 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1193 int rf, int ff, int rt, int ft,
1196 void DisambiguateCallback(board, flags, kind, rf, ff, rt, ft, closure)
1203 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1204 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1206 // [HGM] wild: for wild-card pieces rt and rf are dummies
1207 if(piece == WhiteFalcon || piece == BlackFalcon ||
1208 piece == WhiteCobra || piece == BlackCobra ||
1209 piece == WhiteLance || piece == BlackLance)
1212 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1213 || PieceToChar(board[rf][ff]) == '~'
1214 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1216 (cl->rfIn == -1 || cl->rfIn == rf) &&
1217 (cl->ffIn == -1 || cl->ffIn == ff) &&
1218 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1219 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1222 cl->piece = board[rf][ff];
1225 cl->rt = wildCard ? cl->rtIn : rt;
1226 cl->ft = wildCard ? cl->ftIn : ft;
1231 void Disambiguate(board, flags, closure)
1234 DisambiguateClosure *closure;
1236 int illegal = 0; char c = closure->promoCharIn;
1239 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1240 closure->kind = ImpossibleMove;
1241 if (appData.debugMode) {
1242 fprintf(debugFP, "Disambiguate in: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1243 closure->pieceIn,closure->ffIn,closure->rfIn,closure->ftIn,closure->rtIn,
1244 closure->promoCharIn, closure->promoCharIn >= ' ' ? closure->promoCharIn : '-');
1246 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure);
1247 if (closure->count == 0) {
1248 /* See if it's an illegal move due to check */
1250 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure);
1251 if (closure->count == 0) {
1252 /* No, it's not even that */
1253 if (appData.debugMode) { int i, j;
1254 for(i=BOARD_HEIGHT-1; i>=0; i--) {
1255 for(j=0; j<BOARD_WIDTH; j++)
1256 fprintf(debugFP, "%3d", (int) board[i][j]);
1257 fprintf(debugFP, "\n");
1264 if(gameInfo.variant == VariantShogi) {
1265 /* [HGM] Shogi promotions. '=' means defer */
1266 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
1267 ChessSquare piece = closure->piece;
1268 if(c != NULLCHAR && c != 'x' && c != '+' && c != '=' &&
1269 ToUpper(PieceToChar(PROMOTED piece)) != ToUpper(c) )
1270 closure->kind = IllegalMove;
1271 else if(flags & F_WHITE_ON_MOVE) {
1272 if( (int) piece < (int) WhiteWazir &&
1273 (closure->rf > BOARD_HEIGHT-4 || closure->rt > BOARD_HEIGHT-4) ) {
1274 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
1275 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
1276 closure->kind = c == '=' ? IllegalMove : WhitePromotionKnight;
1277 else /* promotion optional, default is promote */
1278 closure->kind = c == '=' ? NormalMove : WhitePromotionQueen;
1280 } else closure->kind = (c == NULLCHAR || c == 'x' || c == '=') ?
1281 NormalMove : IllegalMove;
1283 if( (int) piece < (int) BlackWazir && (closure->rf < 3 || closure->rt < 3) ) {
1284 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
1285 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
1286 closure->kind = c == '=' ? IllegalMove : BlackPromotionKnight;
1287 else /* promotion optional, default is promote */
1288 closure->kind = c == '=' ? NormalMove : BlackPromotionQueen;
1290 } else closure->kind = (c == NULLCHAR || c == 'x' || c == '=') ?
1291 NormalMove : IllegalMove;
1295 if (closure->promoCharIn != NULLCHAR && closure->promoCharIn != 'x') {
1296 if (closure->kind == WhitePromotionQueen
1297 || closure->kind == BlackPromotionQueen) {
1299 PromoCharToMoveType((flags & F_WHITE_ON_MOVE) != 0,
1300 closure->promoCharIn);
1302 closure->kind = IllegalMove;
1305 /* [HGM] returns 'q' for optional promotion, 'n' for mandatory */
1306 if(closure->promoCharIn != '=')
1307 closure->promoChar = ToLower(closure->promoCharIn);
1308 else closure->promoChar = '=';
1309 if (closure->promoChar == 'x') closure->promoChar = NULLCHAR;
1310 if (closure->count > 1) {
1311 closure->kind = AmbiguousMove;
1314 /* Note: If more than one illegal move matches, but no legal
1315 moves, we return IllegalMove, not AmbiguousMove. Caller
1316 can look at closure->count to detect this.
1318 closure->kind = IllegalMove;
1320 if(closure->kind == IllegalMove)
1321 /* [HGM] might be a variant we don't understand, pass on promotion info */
1322 closure->promoChar = ToLower(closure->promoCharIn);
1323 if (appData.debugMode) {
1324 fprintf(debugFP, "Disambiguate out: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1325 closure->piece,closure->ff,closure->rf,closure->ft,closure->rt,closure->promoChar,
1326 closure->promoChar >= ' ' ? closure->promoChar:'-');
1340 } CoordsToAlgebraicClosure;
1342 extern void CoordsToAlgebraicCallback P((Board board, int flags,
1343 ChessMove kind, int rf, int ff,
1344 int rt, int ft, VOIDSTAR closure));
1346 void CoordsToAlgebraicCallback(board, flags, kind, rf, ff, rt, ft, closure)
1353 register CoordsToAlgebraicClosure *cl =
1354 (CoordsToAlgebraicClosure *) closure;
1356 if (rt == cl->rt && ft == cl->ft &&
1357 (board[rf][ff] == cl->piece
1358 || PieceToChar(board[rf][ff]) == '~' &&
1359 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
1363 cl->kind = kind; /* this is the move we want */
1365 cl->file++; /* need file to rule out this move */
1369 cl->rank++; /* need rank to rule out this move */
1371 cl->either++; /* rank or file will rule out this move */
1377 /* Convert coordinates to normal algebraic notation.
1378 promoChar must be NULLCHAR or 'x' if not a promotion.
1380 ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
1389 char *outp = out, c;
1390 CoordsToAlgebraicClosure cl;
1392 if (rf == DROP_RANK) {
1393 /* Bughouse piece drop */
1394 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
1399 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1401 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
1404 if (promoChar == 'x') promoChar = NULLCHAR;
1405 piece = board[rf][ff];
1406 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
1408 if (appData.debugMode)
1409 fprintf(debugFP, "CoordsToAlgebraic, piece=%d (%d,%d)-(%d,%d) %c\n", (int)piece,ff,rf,ft,rt,promoChar >= ' ' ? promoChar : '-');
1413 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1414 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1415 /* Keep short notation if move is illegal only because it
1416 leaves the player in check, but still return IllegalMove */
1417 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
1418 if (kind == IllegalMove) break;
1423 if (ff == ft && board[rt][ft] == EmptySquare) { /* [HGM] Xiangqi has straight noncapts! */
1424 /* Non-capture; use style "e5" */
1427 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1429 /* Capture; use style "exd5" */
1430 if(gameInfo.variant != VariantXiangqi || board[rt][ft] != EmptySquare )
1431 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
1435 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1437 /* Use promotion suffix style "=Q" */
1439 if (appData.debugMode)
1440 fprintf(debugFP, "movetype=%d, promochar=%d=%c\n", (int)kind, promoChar, promoChar >= ' ' ? promoChar : '-');
1441 if (promoChar != NULLCHAR) {
1442 if(gameInfo.variant == VariantShogi) {
1443 /* [HGM] ... but not in Shogi! */
1444 *outp++ = promoChar == '=' ? '=' : '+';
1447 *outp++ = ToUpper(promoChar);
1456 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
1457 /* Code added by Tord: FRC castling. */
1458 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
1459 (piece == BlackKing && board[rt][ft] == BlackRook)) {
1460 if(ft > ff) strcpy(out, "O-O"); else strcpy(out, "O-O-O");
1461 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1463 /* End of code added by Tord */
1464 /* Test for castling or ICS wild castling */
1465 /* Use style "O-O" (oh-oh) for PGN compatibility */
1466 else if (rf == rt &&
1467 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
1468 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
1469 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
1470 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
1473 strcpy(out, "O-O-O");
1475 /* This notation is always unambiguous, unless there are
1476 kings on both the d and e files, with "wild castling"
1477 possible for the king on the d file and normal castling
1478 possible for the other. ICS rules for wild 9
1479 effectively make castling illegal for either king in
1480 this situation. So I am not going to worry about it;
1481 I'll just generate an ambiguous O-O in this case.
1483 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1486 /* else fall through */
1494 cl.kind = IllegalMove;
1495 cl.rank = cl.file = cl.either = 0;
1496 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl);
1498 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1499 /* Generate pretty moves for moving into check, but
1500 still return IllegalMove.
1502 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl);
1503 if (cl.kind == IllegalMove) break;
1504 cl.kind = IllegalMove;
1507 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
1508 else "Ngf3" or "Ngxf7",
1509 else "N1f3" or "N5xf7",
1510 else "Ng1f3" or "Ng5xf7".
1512 c = PieceToChar(piece) ;
1513 if( c == '~' || c == '+') {
1514 /* [HGM] print nonexistent piece as its demoted version */
1515 piece = (ChessSquare) (DEMOTED piece);
1517 if(c=='+') *outp++ = c;
1518 *outp++ = ToUpper(PieceToChar(piece));
1520 if (cl.file || (cl.either && !cl.rank)) {
1526 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1529 if(board[rt][ft] != EmptySquare)
1535 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1537 if (gameInfo.variant == VariantShogi) {
1538 /* [HGM] in Shogi non-pawns can promote */
1539 if(flags & F_WHITE_ON_MOVE) {
1540 if( (int) cl.piece < (int) WhiteWazir &&
1541 (rf > BOARD_HEIGHT-4 || rt > BOARD_HEIGHT-4) ) {
1542 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1543 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1544 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotionKnight;
1545 else cl.kind = WhitePromotionQueen; /* promotion optional */
1547 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1548 NormalMove : IllegalMove;
1550 if( (int) cl.piece < (int) BlackWazir && (rf < 3 || rt < 3) ) {
1551 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1552 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1553 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotionKnight;
1554 else cl.kind = BlackPromotionQueen; /* promotion optional */
1555 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1556 NormalMove : IllegalMove;
1558 if(cl.kind == WhitePromotionQueen || cl.kind == BlackPromotionQueen) {
1559 /* for optional promotions append '+' or '=' */
1560 if(promoChar == '=') {
1562 cl.kind = NormalMove;
1563 } else *outp++ = '+';
1565 } else if(cl.kind == IllegalMove) {
1566 /* Illegal move specifies any given promotion */
1567 if(promoChar != NULLCHAR && promoChar != 'x') {
1569 *outp++ = ToUpper(promoChar);
1576 /* [HGM] Always long notation for fairies we don't know */
1581 case WhiteGrasshopper:
1582 case BlackGrasshopper:
1584 /* Moving a nonexistent piece */
1588 /* Not a legal move, even ignoring check.
1589 If there was a piece on the from square,
1590 use style "Ng1g3" or "Ng1xe8";
1591 if there was a pawn or nothing (!),
1592 use style "g1g3" or "g1xe8". Use "x"
1593 if a piece was on the to square, even
1594 a piece of the same color.
1597 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
1598 *outp++ = ToUpper(PieceToChar(piece));
1603 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1604 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
1608 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1609 /* Use promotion suffix style "=Q" */
1610 if (promoChar != NULLCHAR && promoChar != 'x') {
1612 *outp++ = ToUpper(promoChar);
1619 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
1628 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
1630 int preyStackPointer, chaseStackPointer;
1633 char rf, ff, rt, ft;
1643 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
1645 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
1646 int rf, int ff, int rt, int ft,
1649 void AttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1655 { // For adding captures that can lead to chase indictment to the chaseStack
1656 if(board[rt][ft] == EmptySquare) return; // non-capture
1657 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
1658 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
1659 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
1660 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
1661 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
1662 chaseStack[chaseStackPointer].rf = rf;
1663 chaseStack[chaseStackPointer].ff = ff;
1664 chaseStack[chaseStackPointer].rt = rt;
1665 chaseStack[chaseStackPointer].ft = ft;
1666 chaseStackPointer++;
1669 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
1670 int rf, int ff, int rt, int ft,
1673 void ExistingAttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1679 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
1681 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
1683 if(board[rt][ft] == EmptySquare) return; // no capture
1684 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
1685 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
1687 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
1688 for(i=0; i<chaseStackPointer; i++) {
1689 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
1690 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
1691 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
1692 chaseStack[i] = chaseStack[--chaseStackPointer];
1698 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
1699 int rf, int ff, int rt, int ft,
1702 void ProtectedCallback(board, flags, kind, rf, ff, rt, ft, closure)
1708 { // for determining if a piece (given through the closure) is protected
1709 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
1711 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
1712 if(appData.debugMode && board[rt][ft] != EmptySquare)
1713 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
1716 extern char moveList[MAX_MOVES][MOVE_LEN];
1718 int PerpetualChase(int first, int last)
1719 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
1722 ChessSquare captured;
1724 preyStackPointer = 0; // clear stack of chased pieces
1725 for(i=first; i<last; i+=2) { // for all positions with same side to move
1726 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
1727 chaseStackPointer = 0; // clear stack that is going to hold possible chases
1728 // determine all captures possible after the move, and put them on chaseStack
1729 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl);
1730 if(appData.debugMode) { int n;
1731 for(n=0; n<chaseStackPointer; n++)
1732 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1733 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1734 fprintf(debugFP, ": all capts\n");
1736 // determine all captures possible before the move, and delete them from chaseStack
1737 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
1738 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
1739 cl.rt = moveList[i][3]-ONE;
1740 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
1741 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl);
1742 if(appData.debugMode) { int n;
1743 for(n=0; n<chaseStackPointer; n++)
1744 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1745 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1746 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
1748 // chaseSack now contains all captures made possible by the move
1749 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
1750 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1751 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1753 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
1754 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
1756 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
1757 continue; // C or H attack on R is always chase; leave on chaseStack
1759 if(attacker == victim) {
1760 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
1761 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
1762 // we can capture back with equal piece, so this is no chase but a sacrifice
1763 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
1764 j--; /* ! */ continue;
1769 // the attack is on a lower piece, or on a pinned or blocked equal one
1770 // test if the victim is protected by a true protector. First make the capture.
1771 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1772 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1773 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
1774 // Then test if the opponent can recapture
1775 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
1776 cl.rt = chaseStack[j].rt;
1777 cl.ft = chaseStack[j].ft;
1778 if(appData.debugMode) {
1779 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
1781 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl); // try all moves
1782 // unmake the capture
1783 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1784 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
1785 // if a recapture was found, piece is protected, and we are not chasing it.
1786 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
1787 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
1791 // chaseStack now contains all moves that chased
1792 if(appData.debugMode) { int n;
1793 for(n=0; n<chaseStackPointer; n++)
1794 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1795 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1796 fprintf(debugFP, ": chases\n");
1798 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
1799 for(j=0; j<chaseStackPointer; j++) {
1800 preyStack[j].rank = chaseStack[j].rt;
1801 preyStack[j].file = chaseStack[j].ft;
1803 preyStackPointer = chaseStackPointer;
1806 for(j=0; j<chaseStackPointer; j++) {
1807 for(k=0; k<preyStackPointer; k++) {
1808 // search the victim of each chase move on the preyStack (first occurrence)
1809 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
1810 if(k < tail) break; // piece was already identified as still being chased
1811 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
1812 preyStack[tail] = preyStack[k]; // by swapping
1813 preyStack[k] = preyStack[preyStackPointer];
1819 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
1820 if(appData.debugMode) { int n;
1821 for(n=0; n<preyStackPointer; n++)
1822 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
1823 fprintf(debugFP, "always chased upto ply %d\n", i);
1825 // now adjust the location of the chased pieces according to opponent move
1826 for(j=0; j<preyStackPointer; j++) {
1827 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
1828 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
1829 preyStack[j].rank = moveList[i+1][3]-ONE;
1830 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
1835 return preyStackPointer; // if any piece was left on preyStack, it has been perpetually chased