aboutsummaryrefslogtreecommitdiffstats
path: root/FICS/algcheck.c
blob: 67609b104dbfd18436759878eba289f4cf8ee7e9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
/* algcheck.c
 *
 */

/*
    fics - An internet chess server.
    Copyright (C) 1993  Richard V. Nash

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
*/

/* Revision history:
   name		email		yy/mm/dd	Change
   Richard Nash                 93/10/22	Created
   Markus Uhlin                 24/01/04	Reformatted functions
   Markus Uhlin                 24/01/06	Switched to usage of strlcpy,
						strlcat and snprintf. Also added
						truncation checks.
*/

#include "stdinclude.h"
#include "common.h"

#include "algcheck.h"
#include "board.h"
#include "movecheck.h"
#include "utils.h"

#if __linux__
#include <bsd/string.h>
#endif

/* Well, lets see if I can list the possibilities
 * Piece moves
 * Ne4
 * Nxe4
 * Nce4
 * Ncxe4
 * R2f3
 * R2xf3
 * Special pawn moves
 * e4
 * ed
 * exd
 * exd5
 * ed5
 * Drop moves (bughouse, board edit)
 * P@f7 P*f7
 * #f7 #Nf7
 * (o-o, o-o-o) Castling is handled earlier, so don't worry about that
 * Of course any of these can have a + or ++ or = string on the end, just
 * cut that off.
 */

/* f - file
 * r - rank
 * p - piece
 * x - x
 * @ - drop character (bughouse)
 */
PRIVATE char *alg_list[] = {
	"fxfr", "pxfr",  /* These two get confused in case of bishop */
	"ffr", "pfr",    /* These two get confused in case of bishop */
	"pffr",
	"pfxfr",
	"prfr",
	"prxfr",
	"fr",
	"ff",
	"fxf",
	"p@fr",
	"#fr",
	"#pfr",
	NULL
};

PRIVATE int
get_move_info(char *str, int *piece, int *ff, int *fr, int *tf, int *tr,
	      int *bishconfusion)
{
	char	*s;
	char	 c;
	char	 tmp[1024] = { '\0' };
	int	 i, j, len;
	int	 lpiece, lff, lfr, ltf, ltr;
	int	 matchVal = -1;

	*bishconfusion = 0;
	strlcpy(tmp, str, sizeof tmp);

	if ((s = strchr(tmp, '+')) != NULL) {	// Cut off any check marks
		*s = '\0';
	}
	if ((s = strchr(tmp, '=')) != NULL) {	// Cut off any promotion marks
		*s = '\0';
	}

	*piece = *ff = *fr = *tf = *tr = ALG_UNKNOWN;
	len = strlen(tmp);

	for (i = 0; alg_list[i]; i++) {
		lpiece = lff = lfr = ltf = ltr = ALG_UNKNOWN;

		if (strlen(alg_list[i]) != len)
			continue;

		for (j = len - 1; j >= 0; j--) {
			switch (alg_list[i][j]) {
			case 'f':
				if (tmp[j] < 'a' || tmp[j] > 'h')
					goto nomatch;

				if (ltf == ALG_UNKNOWN)
					ltf = (tmp[j] - 'a');
				else
					lff = (tmp[j] - 'a');
				break;
			case 'r':
				if (tmp[j] < '1' || tmp[j] > '8')
					goto nomatch;

				if (ltr == ALG_UNKNOWN)
					ltr = (tmp[j] - '1');
				else
					lfr = (tmp[j] - '1');
				break;
			case 'p':
				if (isupper(tmp[j]))
					c = tolower(tmp[j]);
				else
					c = tmp[j];

				if (c == 'k')
					lpiece = KING;
				else if (c == 'q')
					lpiece = QUEEN;
				else if (c == 'r')
					lpiece = ROOK;
				else if (c == 'b')
					lpiece = BISHOP;
				else if (c == 'n')
					lpiece = KNIGHT;
				else if (c == 'p')
					lpiece = PAWN;
				else
					goto nomatch;
				break;
			case 'x':
				if (tmp[j] != 'x' && tmp[j] != 'X')
					goto nomatch;
				break;
			case '@':
				if (tmp[j] != '@' && tmp[j] != '*')
					goto nomatch;
				lff = lfr = ALG_DROP;
				break;
			case '#':
				if (tmp[j] != '#')
					goto nomatch;
				lff = lfr = ALG_DROP;
				break;
			default:
				fprintf(stderr, "Unknown character in "
				    "algebraic parsing\n");
				break;
			}
		}

		if (lpiece == ALG_UNKNOWN)
			lpiece = PAWN;

		if (lpiece == PAWN && lfr == ALG_UNKNOWN) { // ffr or ff
			if (lff != ALG_UNKNOWN) {
				if (lff == ltf)
					goto nomatch;
				if ((lff - ltf) != 1 && (ltf - lff) != 1)
					goto nomatch;
			}
		}

		*piece = lpiece; // We have a match

		*tf = ltf;
		*tr = ltr;
		*ff = lff;
		*fr = lfr;

		if (matchVal != -1) {
			/*
			 * We have two matches, it must be that Bxc4
			 * vs. bxc4 problem. Or it could be the Bc4 vs
			 * bc4 problem.
			 */
			*bishconfusion = 1;
		}

		matchVal = i;

	  nomatch:;
	}

	if (matchVal != -1)
		return MS_ALG;
	else
		return MS_NOTMOVE;
}

PUBLIC int
alg_is_move(char *mstr)
{
	int piece, ff, fr, tf, tr, bc;

	return get_move_info(mstr, &piece, &ff, &fr, &tf, &tr, &bc);
}

/*
 * We already know it is algebraic. Get the move squares.
 */
PUBLIC int
alg_parse_move(char *mstr, game_state_t *gs, move_t *mt)
{
	int	f, r, tmpr, posf, posr, posr2;
	int	piece, ff, fr, tf, tr, bc;

	if (get_move_info(mstr, &piece, &ff, &fr, &tf, &tr, &bc) != MS_ALG) {
		fprintf(stderr, "FICS: Shouldn't try to algebraically parse "
		    "non-algebraic move string.\n");
		return MOVE_ILLEGAL;
	}

	if (tf == ALG_UNKNOWN)
		return MOVE_AMBIGUOUS; /* Must always know to file */

	if (tr == ALG_UNKNOWN) {
		posr = posr2 = ALG_UNKNOWN;

		if (piece != PAWN)
			return MOVE_AMBIGUOUS;
		if (ff == ALG_UNKNOWN)
			return MOVE_AMBIGUOUS;

		/*
		 * Need to find pawn on ff that can take to tf and
		 * fill in ranks.
		 */
		for (InitPieceLoop(gs->board, &f, &r, gs->onMove);
		     NextPieceLoop(gs->board, &f, &r, gs->onMove);) {
			if (ff != ALG_UNKNOWN && ff != f)
				continue;
			if (piecetype(gs->board[f][r]) != piece)
				continue;

			if (gs->onMove == WHITE) {
				tmpr = r + 1;
			} else {
				tmpr = r - 1;
			}

			if (gs->board[tf][tmpr] == NOPIECE) {
				const int is_black = (gs->onMove == WHITE ?
				    0 : 1);

				if (gs->ep_possible[is_black][ff] != (tf - ff))
					continue;
			} else {
				if (iscolor(gs->board[tf][tmpr], gs->onMove))
					continue;
			}

			if (legal_andcheck_move(gs, f, r, tf, tmpr)) {
				if (posr != ALG_UNKNOWN && posr2 != ALG_UNKNOWN)
					return MOVE_AMBIGUOUS;

				posr = tmpr;
				posr2 = r;
			}
		}

		tr = posr;
		fr = posr2;
	} else if (bc) { /* Could be bxc4 or Bxc4, tr is known. */
		ff = ALG_UNKNOWN;
		fr = ALG_UNKNOWN;

		for (InitPieceLoop(gs->board, &f, &r, gs->onMove);
		     NextPieceLoop(gs->board, &f, &r, gs->onMove);) {
			if (piecetype(gs->board[f][r]) != PAWN &&
			    piecetype(gs->board[f][r]) != BISHOP)
				continue;
			if (legal_andcheck_move(gs, f, r, tf, tr)) {
				if (piecetype(gs->board[f][r]) == PAWN &&
				    f != 1)
					continue;
				if (ff != ALG_UNKNOWN && fr != ALG_UNKNOWN)
					return (MOVE_AMBIGUOUS);

				ff = f;
				fr = r;
			}
		}
	} else {	/* The from position is unknown */
		posf = ALG_UNKNOWN;
		posr = ALG_UNKNOWN;

		if (ff == ALG_UNKNOWN || fr == ALG_UNKNOWN) {
			/*
			 * Need to find a piece that can go to tf, tr.
			 */
			for (InitPieceLoop(gs->board, &f, &r, gs->onMove);
			     NextPieceLoop(gs->board, &f, &r, gs->onMove);) {
				if (ff != ALG_UNKNOWN && ff != f)
					continue;
				if (fr != ALG_UNKNOWN && fr != r)
					continue;
				if (piecetype(gs->board[f][r]) != piece)
					continue;

				if (legal_andcheck_move(gs, f, r, tf, tr)) {
					if (posf != ALG_UNKNOWN &&
					    posr != ALG_UNKNOWN)
						return MOVE_AMBIGUOUS;

					posf = f;
					posr = r;
				}
			}
		} else if (ff == ALG_DROP) {
			if (legal_andcheck_move(gs, ALG_DROP, piece, tf, tr)) {
				posf = ALG_DROP;
				posr = piece;
			}
		}

		ff = posf;
		fr = posr;
	}

	if (tf == ALG_UNKNOWN || tr == ALG_UNKNOWN || ff == ALG_UNKNOWN ||
	    fr == ALG_UNKNOWN)
		return MOVE_ILLEGAL;

	mt->fromFile = ff;
	mt->fromRank = fr;
	mt->toFile = tf;
	mt->toRank = tr;

	return MOVE_OK;
}

PRIVATE void
not_pawn(game_state_t *gs, move_t *mt, game_state_t *fakeMove, const int piece,
	 char *tmp, char *mStr, size_t tmp_size, size_t mStr_size)
{
	int ambig, r_ambig, f_ambig;

	ambig = r_ambig = f_ambig = 0;

	for (int r = 0; r < 8; r++) {
		for (int f = 0; f < 8; f++) {
			if (gs->board[f][r] != NOPIECE &&
			    iscolor(gs->board[f][r], gs->onMove) &&
			    piecetype(gs->board[f][r]) == piece &&
			    (f != mt->fromFile || r != mt->fromRank)) {
				if (legal_move(gs, f, r, mt->toFile,
				    mt->toRank)) {
					fakeMove = gs;
					fakeMove->board[f][r] = NOPIECE;
					fakeMove->onMove =
					    CToggle(fakeMove->onMove);
					gs->onMove = CToggle(gs->onMove);

					/*
					 * New bracketing below to try
					 * to fix 'ambiguous move'
					 * bug.
					 */

					if (in_check(gs) || !in_check(fakeMove))
						ambig++;

					if (f == mt->fromFile) {
						f_ambig++;
						ambig++;
					}
					if (r == mt->fromRank) {
						r_ambig++;
						ambig++;
					}

					gs->onMove = CToggle(gs->onMove);
				}
			}
		} /* for */
	} /* for */

	if (ambig > 0) {
		/*
		 * Ambiguity in short notation. Need to add file, rank
		 * or _both_ in notation.
		 */

		if (f_ambig == 0) {
			snprintf(tmp, tmp_size, "%c", (mt->fromFile + 'a'));
			strlcat(mStr, tmp, mStr_size);
		} else if (r_ambig == 0) {
			snprintf(tmp, tmp_size, "%d", (mt->fromRank + 1));
			strlcat(mStr, tmp, mStr_size);
		} else {
			snprintf(tmp, tmp_size, "%c%d",
			    (mt->fromFile + 'a'),
			    (mt->fromRank + 1));
			strlcat(mStr, tmp, mStr_size);
		}
	}
}

/*
 * Soso: rewrote alg_unparse function.  Algebraic deparser - sets the
 * 'mStr' variable with move description in short notation. Used in
 * last move report and in 'moves' command.
 */
PUBLIC char *
alg_unparse(game_state_t *gs, move_t *mt)
{
	char		tmp[20] = { '\0' };
	game_state_t	fakeMove;
	int		piece;
	size_t		ret = 0;
	static char	mStr[20] = { '\0' };

	if (mt->fromFile == ALG_DROP) {
		piece = mt->fromRank;
	} else {
		piece = piecetype(gs->board[mt->fromFile][mt->fromRank]);
	}

	if (piece == KING && (mt->fromFile == 4 && mt->toFile == 6)) {
		strlcpy(mStr, "O-O", sizeof mStr);
		goto check;
	}

	if (piece == KING && (mt->fromFile == 4 && mt->toFile == 2)) {
		strlcpy(mStr, "O-O-O", sizeof mStr);
		goto check;
	}

	mStr[0] = '\0';

	switch (piece) {
	case PAWN:
		if (mt->fromFile == ALG_DROP) {
			strlcpy(mStr, "P", sizeof mStr);
		} else if (mt->fromFile != mt->toFile) {
			snprintf(tmp, sizeof tmp, "%c", (mt->fromFile + 'a'));
			strlcpy(mStr, tmp, sizeof mStr);
		}
		break;
	case KNIGHT:
		strlcpy(mStr, "N", sizeof mStr);
		break;
	case BISHOP:
		strlcpy(mStr, "B", sizeof mStr);
		break;
	case ROOK:
		strlcpy(mStr, "R", sizeof mStr);
		break;
	case QUEEN:
		strlcpy(mStr, "Q", sizeof mStr);
		break;
	case KING:
		strlcpy(mStr, "K", sizeof mStr);
		break;
	default:
		strlcpy(mStr, "", sizeof mStr);
		break;
	} /* switch */

	if (mt->fromFile == ALG_DROP) {
		strlcat(mStr, DROP_STR, sizeof mStr);
	} else {
		/*
		 * Checks for ambiguity in short notation (Ncb3, R8e8
		 * or so.)
		 */

		if (piece != PAWN) {
			not_pawn(gs, mt, &fakeMove, piece, &tmp[0], &mStr[0],
			    sizeof tmp, sizeof mStr);
		} /* not pawn */

		if (gs->board[mt->toFile][mt->toRank] != NOPIECE ||
		    (piece == PAWN && mt->fromFile != mt->toFile))
			strlcat(mStr, "x", sizeof mStr);
	}

	snprintf(tmp, sizeof tmp, "%c%d", (mt->toFile + 'a'), (mt->toRank + 1));
	ret = strlcat(mStr, tmp, sizeof mStr);

	if (ret >= sizeof mStr) {
		fprintf(stderr, "FICS: %s (line %d): warning: "
		    "strlcat() truncated\n", __func__, __LINE__);
	}

	if (piece == PAWN && mt->piecePromotionTo != NOPIECE) {
		strlcat(mStr, "=", sizeof mStr); /* = before promoting piece */

		switch (piecetype(mt->piecePromotionTo)) {
		case KNIGHT:
			strlcat(mStr, "N", sizeof mStr);
			break;
		case BISHOP:
			strlcat(mStr, "B", sizeof mStr);
			break;
		case ROOK:
			strlcat(mStr, "R", sizeof mStr);
			break;
		case QUEEN:
			strlcat(mStr, "Q", sizeof mStr);
			break;
		default:
			break;
		}
	}

  check:;

	fakeMove = *gs;
	execute_move(&fakeMove, mt, 0);
	fakeMove.onMove = CToggle(fakeMove.onMove);

	if (in_check(&fakeMove)) {
		ret = strlcat(mStr, "+", sizeof mStr);

		if (ret >= sizeof mStr) {
			fprintf(stderr, "FICS: %s (line %d): warning: "
			    "strlcat() truncated\n", __func__, __LINE__);
		}
	}

	return mStr;
}