Mercurial > hg > terminal-chess / file comparison
comparison: src/chess/knight.c
src/chess/knight.c
- changeset 19
- 6a26114297a1
- parent 16
- a298c6637c30
- child 23
- 824c9522ce66
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| 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 "knight.h" | |
| 31 #include "rules.h" | |
| 32 #include <stdlib.h> | |
| 33 | |
| 34 _Bool knight_chkrules(Move *move) { | |
| 35 int dx = abs(move->fromfile - move->tofile); | |
| 36 int dy = abs(move->fromrow - move->torow); | |
| 37 | |
| 38 return (dx == 2 && dy == 1) || (dx == 1 && dy == 2); | |
| 39 } | |
| 40 | |
| 41 static int knight_getloc_fixedrow(Board board, Move *move) { | |
| 42 int d = 3 - abs(move->fromrow - move->torow); | |
| 43 | |
| 44 if (d == 1 || d == 2) { | |
| 45 if (move->tofile < 6 && | |
| 46 board[move->fromrow][move->tofile + d] == move->piece) { | |
| 47 if (move->fromfile == POS_UNSPECIFIED) { | |
| 48 move->fromfile = move->tofile + d; | |
| 49 return VALID_MOVE_SYNTAX; | |
| 50 } else { | |
| 51 return AMBIGUOUS_MOVE; | |
| 52 } | |
| 53 } | |
| 54 if (move->tofile > 1 && | |
| 55 board[move->fromrow][move->tofile - d] == move->piece) { | |
| 56 if (move->fromfile == POS_UNSPECIFIED) { | |
| 57 move->fromfile = move->tofile - d; | |
| 58 return VALID_MOVE_SYNTAX; | |
| 59 } else { | |
| 60 return AMBIGUOUS_MOVE; | |
| 61 } | |
| 62 } | |
| 63 } | |
| 64 | |
| 65 return INVALID_POSITION; | |
| 66 } | |
| 67 | |
| 68 static int knight_getloc_fixedfile(Board board, Move *move) { | |
| 69 int d = 3 - abs(move->fromfile - move->tofile); | |
| 70 | |
| 71 if (d == 1 || d == 2) { | |
| 72 if (move->torow < 6 && | |
| 73 board[move->torow + d][move->fromfile] == move->piece) { | |
| 74 if (move->fromrow == POS_UNSPECIFIED) { | |
| 75 move->fromrow = move->torow + d; | |
| 76 return VALID_MOVE_SYNTAX; | |
| 77 } else { | |
| 78 return AMBIGUOUS_MOVE; | |
| 79 } | |
| 80 } | |
| 81 if (move->torow > 1 && | |
| 82 board[move->torow - d][move->fromfile] == move->piece) { | |
| 83 if (move->fromrow == POS_UNSPECIFIED) { | |
| 84 move->fromrow = move->torow - d; | |
| 85 return VALID_MOVE_SYNTAX; | |
| 86 } else { | |
| 87 return AMBIGUOUS_MOVE; | |
| 88 } | |
| 89 } | |
| 90 } | |
| 91 | |
| 92 return INVALID_POSITION; | |
| 93 } | |
| 94 | |
| 95 int knight_getlocation(Board board, Move *move) { | |
| 96 | |
| 97 if (move->fromfile != POS_UNSPECIFIED) { | |
| 98 return knight_getloc_fixedfile(board, move); | |
| 99 } | |
| 100 | |
| 101 if (move->fromrow != POS_UNSPECIFIED) { | |
| 102 return knight_getloc_fixedrow(board, move); | |
| 103 } | |
| 104 | |
| 105 for (int x = -2 ; x <= 2 ; x++) { | |
| 106 if (x == 0) { | |
| 107 continue; | |
| 108 } | |
| 109 for (int y = -2 ; y <= 2 ; y++) { | |
| 110 if (y == 0 || y == x) { | |
| 111 continue; | |
| 112 } | |
| 113 uint8_t cx = move->tofile + x; | |
| 114 uint8_t cy = move->torow + y; | |
| 115 | |
| 116 if (isidx(cx) && isidx(cy) && board[cy][cx] == move->piece) { | |
| 117 if (move->fromfile == POS_UNSPECIFIED | |
| 118 && move->fromrow == POS_UNSPECIFIED) { | |
| 119 move->fromfile = cx; | |
| 120 move->fromrow = cy; | |
| 121 } else { | |
| 122 return AMBIGUOUS_MOVE; | |
| 123 } | |
| 124 } | |
| 125 } | |
| 126 } | |
| 127 | |
| 128 if (move->fromfile == POS_UNSPECIFIED || move->fromrow == POS_UNSPECIFIED) { | |
| 129 return INVALID_POSITION; | |
| 130 } else { | |
| 131 return VALID_MOVE_SYNTAX; | |
| 132 } | |
| 133 } |
