Mercurial > hg > terminal-chess / file comparison

comparison: src/chess/rules.c

src/chess/rules.c

changeset 19
6a26114297a1
child 21
2e5846019b4f
equal deleted inserted replaced
18:6008840b859e 19:6a26114297a1
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2014 Mike Becker. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 *
28 */
29
30 #include "rules.h"
31 #include "chess.h"
32 #include <string.h>
33
34 char getpiecechr(uint8_t piece) {
35 switch (piece & PIECE_MASK) {
36 case ROOK: return 'R';
37 case KNIGHT: return 'N';
38 case BISHOP: return 'B';
39 case QUEEN: return 'Q';
40 case KING: return 'K';
41 default: return '\0';
42 }
43 }
44
45 uint8_t getpiece(char c) {
46 switch (c) {
47 case 'R': return ROOK;
48 case 'N': return KNIGHT;
49 case 'B': return BISHOP;
50 case 'Q': return QUEEN;
51 case 'K': return KING;
52 default: return 0;
53 }
54 }
55
56 /**
57 * Guesses the location of a piece for short algebraic notation.
58 *
59 * @param board the current state of the board
60 * @param move the move date to operate on
61 * @return status code (see rules/rules.h for the codes)
62 */
63 static int getlocation(Board board, Move *move) {
64 uint8_t piece = move->piece & PIECE_MASK;
65 switch (piece) {
66 case PAWN: return pawn_getlocation(board, move);
67 case ROOK: return rook_getlocation(board, move);
68 case KNIGHT: return knight_getlocation(board, move);
69 case BISHOP: return bishop_getlocation(board, move);
70 case QUEEN: return queen_getlocation(board, move);
71 case KING: return king_getlocation(board, move);
72 default: return INVALID_MOVE_SYNTAX;
73 }
74 }
75
76
77 void apply_move(Board board, Move *move) {
78 uint8_t piece = move->piece & PIECE_MASK;
79 uint8_t color = move->piece & COLOR_MASK;
80
81 /* en passant capture */
82 if (move->capture && piece == PAWN &&
83 mdst(board, move) == 0) {
84 board[move->fromrow][move->tofile] = 0;
85 }
86
87 /* remove old en passant threats */
88 for (uint8_t file = 0 ; file < 8 ; file++) {
89 board[3][file] &= ~ENPASSANT_THREAT;
90 board[4][file] &= ~ENPASSANT_THREAT;
91 }
92
93 /* add new en passant threat */
94 if (piece == PAWN && (
95 (move->fromrow == 1 && move->torow == 3) ||
96 (move->fromrow == 6 && move->torow == 4))) {
97 move->piece |= ENPASSANT_THREAT;
98 }
99
100 /* move (and maybe capture or promote) */
101 msrc(board, move) = 0;
102 if (move->promotion) {
103 mdst(board, move) = move->promotion;
104 } else {
105 mdst(board, move) = move->piece;
106 }
107
108 /* castling */
109 if (piece == KING &&
110 move->fromfile == fileidx('e')) {
111
112 if (move->tofile == fileidx('g')) {
113 board[move->torow][fileidx('h')] = 0;
114 board[move->torow][fileidx('f')] = color|ROOK;
115 } else if (move->tofile == fileidx('c')) {
116 board[move->torow][fileidx('a')] = 0;
117 board[move->torow][fileidx('d')] = color|ROOK;
118 }
119 }
120 }
121
122 _Bool validate_move(Board board, Move *move) {
123 _Bool result;
124
125 /* validate indices (don't trust opponent) */
126 if (!chkidx(move)) {
127 return 0;
128 }
129
130 /* does piece exist */
131 result = msrc(board, move) == move->piece;
132
133 /* can't capture own pieces */
134 if ((mdst(board, move) & COLOR_MASK) == (move->piece & COLOR_MASK)) {
135 return 0;
136 }
137
138 /* validate individual rules */
139 switch (move->piece & PIECE_MASK) {
140 case PAWN:
141 result = result && pawn_chkrules(board, move);
142 result = result && !pawn_isblocked(board, move);
143 break;
144 case ROOK:
145 result = result && rook_chkrules(move);
146 result = result && !rook_isblocked(board, move);
147 break;
148 case KNIGHT:
149 result = result && knight_chkrules(move);
150 result = result && !knight_isblocked(board, move);
151 break;
152 case BISHOP:
153 result = result && bishop_chkrules(move);
154 result = result && !bishop_isblocked(board, move);
155 break;
156 case QUEEN:
157 result = result && queen_chkrules(move);
158 result = result && !queen_isblocked(board, move);
159 break;
160 case KING:
161 result = result && king_chkrules(board, move);
162 result = result && !king_isblocked(board, move);
163 break;
164 default:
165 result = 0;
166 }
167
168 /* is piece pinned */
169 // TODO: make it so
170
171 /* correct check and checkmate flags */
172 // TODO: make it so
173
174 return result;
175 }
176
177 int eval_move(Board board, uint8_t mycolor, char *mstr, Move *move) {
178 memset(move, 0, sizeof(Move));
179 move->fromfile = POS_UNSPECIFIED;
180 move->fromrow = POS_UNSPECIFIED;
181
182 size_t len = strlen(mstr);
183
184 /* evaluate check/checkmate flags */
185 if (mstr[len-1] == '+') {
186 len--; mstr[len] = '\0';
187 move->check = 1;
188 } else if (mstr[len-1] == '#') {
189 len--; mstr[len] = '\0';
190 move->checkmate = 1;
191 }
192
193 /* evaluate promotion */
194 if (len > 3 && mstr[len-2] == '=') {
195 move->promotion = getpiece(mstr[len-1]);
196 if (!move->promotion) {
197 return INVALID_MOVE_SYNTAX;
198 } else {
199 move->promotion |= mycolor;
200 len -= 2;
201 mstr[len] = 0;
202 }
203 }
204
205 if (len == 2) {
206 /* pawn move (e.g. "e4") */
207 move->piece = PAWN;
208 move->tofile = fileidx(mstr[0]);
209 move->torow = rowidx(mstr[1]);
210 } else if (len == 3) {
211 if (strcmp(mstr, "O-O") == 0) {
212 /* king side castling */
213 move->piece = KING;
214 move->fromfile = fileidx('e');
215 move->tofile = fileidx('g');
216 move->fromrow = move->torow = mycolor == WHITE ? 0 : 7;
217 } else {
218 /* move (e.g. "Nf3") */
219 move->piece = getpiece(mstr[0]);
220 move->tofile = fileidx(mstr[1]);
221 move->torow = rowidx(mstr[2]);
222 }
223
224 } else if (len == 4) {
225 move->piece = getpiece(mstr[0]);
226 if (!move->piece) {
227 move->piece = PAWN;
228 move->fromfile = fileidx(mstr[0]);
229 }
230 if (mstr[1] == 'x') {
231 /* capture (e.g. "Nxf3", "dxe5") */
232 move->capture = 1;
233 } else {
234 /* move (e.g. "Ndf3", "N2c3", "e2e4") */
235 if (isfile(mstr[1])) {
236 move->fromfile = fileidx(mstr[1]);
237 if (move->piece == PAWN) {
238 move->piece = 0;
239 }
240 } else {
241 move->fromrow = rowidx(mstr[1]);
242 }
243 }
244 move->tofile = fileidx(mstr[2]);
245 move->torow = rowidx(mstr[3]);
246 } else if (len == 5) {
247 if (strcmp(mstr, "O-O-O") == 0) {
248 /* queen side castling "O-O-O" */
249 move->piece = KING;
250 move->fromfile = fileidx('e');
251 move->tofile = fileidx('c');
252 move->fromrow = move->torow = mycolor == WHITE ? 0 : 7;
253 } else {
254 move->piece = getpiece(mstr[0]);
255 if (mstr[2] == 'x') {
256 move->capture = 1;
257 if (move->piece) {
258 /* capture (e.g. "Ndxf3") */
259 move->fromfile = fileidx(mstr[1]);
260 } else {
261 /* long notation capture (e.g. "e5xf6") */
262 move->piece = PAWN;
263 move->fromfile = fileidx(mstr[0]);
264 move->fromrow = rowidx(mstr[1]);
265 }
266 } else {
267 /* long notation move (e.g. "Nc5a4") */
268 move->fromfile = fileidx(mstr[1]);
269 move->fromrow = rowidx(mstr[2]);
270 }
271 move->tofile = fileidx(mstr[3]);
272 move->torow = rowidx(mstr[4]);
273 }
274 } else if (len == 6) {
275 /* long notation capture (e.g. "Nc5xf3") */
276 if (mstr[3] == 'x') {
277 move->capture = 1;
278 move->piece = getpiece(mstr[0]);
279 move->fromfile = fileidx(mstr[1]);
280 move->fromrow = rowidx(mstr[2]);
281 move->tofile = fileidx(mstr[4]);
282 move->torow = rowidx(mstr[5]);
283 }
284 }
285
286
287 if (move->piece) {
288 if (move->piece == PAWN && move->torow == (mycolor==WHITE?7:0)
289 && !move->promotion) {
290 return NEED_PROMOTION;
291 }
292
293 move->piece |= mycolor;
294 if (move->fromfile == POS_UNSPECIFIED
295 || move->fromrow == POS_UNSPECIFIED) {
296 return getlocation(board, move);
297 } else {
298 return chkidx(move) ? VALID_MOVE_SYNTAX : INVALID_POSITION;
299 }
300 } else {
301 return INVALID_MOVE_SYNTAX;
302 }
303 }

Mercurial Repository: terminal-chess

mercurial