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comparison: src/chess/bishop.c

src/chess/bishop.c

changeset 19
6a26114297a1
parent 18
6008840b859e
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 "bishop.h"
31 #include "rules.h"
32 #include <stdlib.h>
33
34 _Bool bishop_chkrules(Move* move) {
35 return abs(move->torow-move->fromrow) == abs(move->tofile-move->fromfile);
36 }
37
38 _Bool bishop_isblocked(Board board, Move *move) {
39 int dy = move->torow > move->fromrow ? 1 : -1;
40 int dx = move->tofile > move->fromfile ? 1 : -1;
41
42 uint8_t y = move->fromrow;
43 uint8_t x = move->fromfile;
44
45 do {
46 x += dx;
47 y += dy;
48 if (board[y][x]) {
49 return 1;
50 }
51 } while (x != move->tofile && y != move->torow);
52
53 return 0;
54 }
55
56 static int bishop_getloc_fixedfile(Board board, Move *move) {
57 uint8_t d = abs(move->fromfile - move->tofile);
58 if (board[move->torow - d][move->fromfile] == move->piece) {
59 move->fromrow = move->torow - d;
60 }
61 if (board[move->torow + d][move->fromfile] == move->piece) {
62 if (move->fromrow == POS_UNSPECIFIED) {
63 move->fromrow = move->torow + d;
64 } else {
65 return AMBIGUOUS_MOVE; /* rare situation after promotion */
66 }
67 }
68 return move->fromrow == POS_UNSPECIFIED ?
69 INVALID_POSITION : VALID_MOVE_SYNTAX;
70 }
71
72 static int bishop_getloc_fixedrow(Board board, Move *move) {
73 uint8_t d = abs(move->fromrow - move->torow);
74 if (board[move->fromrow][move->tofile - d] == move->piece) {
75 move->fromfile = move->tofile - d;
76 }
77 if (board[move->fromrow][move->tofile + d] == move->piece) {
78 if (move->fromfile == POS_UNSPECIFIED) {
79 move->fromfile = move->tofile + d;
80 } else {
81 return AMBIGUOUS_MOVE; /* rare situation after promotion */
82 }
83 }
84 return move->fromfile == POS_UNSPECIFIED ?
85 INVALID_POSITION : VALID_MOVE_SYNTAX;
86 }
87
88 int bishop_getlocation(Board board, Move *move) {
89
90 if (move->fromfile != POS_UNSPECIFIED) {
91 return bishop_getloc_fixedfile(board, move);
92 }
93
94 if (move->fromrow != POS_UNSPECIFIED) {
95 return bishop_getloc_fixedrow(board, move);
96 }
97
98 _Bool amb = 0;
99 for (int d = -7 ; d < 8 ; d++) {
100 uint8_t row = move->torow + d;
101 if (isidx(row)) {
102 uint8_t file = move->tofile + d;
103 if (isidx(file) && board[row][file] == move->piece) {
104 if (amb) {
105 return AMBIGUOUS_MOVE;
106 }
107 amb = 1;
108 move->fromrow = row;
109 move->fromfile = file;
110 }
111 file = move->tofile - d;
112 if (isidx(file) && board[row][file] == move->piece) {
113 if (amb) {
114 return AMBIGUOUS_MOVE;
115 }
116 amb = 1;
117 move->fromrow = row;
118 move->fromfile = file;
119 }
120 }
121 }
122
123 if (move->fromrow == POS_UNSPECIFIED || move->fromfile == POS_UNSPECIFIED) {
124 return INVALID_POSITION;
125 } else {
126 return VALID_MOVE_SYNTAX;
127 }
128 }

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