1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/chess/bishop.c Mon Mar 31 11:16:32 2014 +0200
1.3 @@ -0,0 +1,128 @@
1.4 +/*
1.5 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
1.6 + *
1.7 + * Copyright 2014 Mike Becker. All rights reserved.
1.8 + *
1.9 + * Redistribution and use in source and binary forms, with or without
1.10 + * modification, are permitted provided that the following conditions are met:
1.11 + *
1.12 + * 1. Redistributions of source code must retain the above copyright
1.13 + * notice, this list of conditions and the following disclaimer.
1.14 + *
1.15 + * 2. Redistributions in binary form must reproduce the above copyright
1.16 + * notice, this list of conditions and the following disclaimer in the
1.17 + * documentation and/or other materials provided with the distribution.
1.18 + *
1.19 + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
1.20 + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.21 + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1.22 + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
1.23 + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
1.24 + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
1.25 + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
1.26 + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
1.27 + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.28 + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1.29 + * POSSIBILITY OF SUCH DAMAGE.
1.30 + *
1.31 + */
1.32 +
1.33 +#include "bishop.h"
1.34 +#include "rules.h"
1.35 +#include <stdlib.h>
1.36 +
1.37 +_Bool bishop_chkrules(Move* move) {
1.38 + return abs(move->torow-move->fromrow) == abs(move->tofile-move->fromfile);
1.39 +}
1.40 +
1.41 +_Bool bishop_isblocked(Board board, Move *move) {
1.42 + int dy = move->torow > move->fromrow ? 1 : -1;
1.43 + int dx = move->tofile > move->fromfile ? 1 : -1;
1.44 +
1.45 + uint8_t y = move->fromrow;
1.46 + uint8_t x = move->fromfile;
1.47 +
1.48 + do {
1.49 + x += dx;
1.50 + y += dy;
1.51 + if (board[y][x]) {
1.52 + return 1;
1.53 + }
1.54 + } while (x != move->tofile && y != move->torow);
1.55 +
1.56 + return 0;
1.57 +}
1.58 +
1.59 +static int bishop_getloc_fixedfile(Board board, Move *move) {
1.60 + uint8_t d = abs(move->fromfile - move->tofile);
1.61 + if (board[move->torow - d][move->fromfile] == move->piece) {
1.62 + move->fromrow = move->torow - d;
1.63 + }
1.64 + if (board[move->torow + d][move->fromfile] == move->piece) {
1.65 + if (move->fromrow == POS_UNSPECIFIED) {
1.66 + move->fromrow = move->torow + d;
1.67 + } else {
1.68 + return AMBIGUOUS_MOVE; /* rare situation after promotion */
1.69 + }
1.70 + }
1.71 + return move->fromrow == POS_UNSPECIFIED ?
1.72 + INVALID_POSITION : VALID_MOVE_SYNTAX;
1.73 +}
1.74 +
1.75 +static int bishop_getloc_fixedrow(Board board, Move *move) {
1.76 + uint8_t d = abs(move->fromrow - move->torow);
1.77 + if (board[move->fromrow][move->tofile - d] == move->piece) {
1.78 + move->fromfile = move->tofile - d;
1.79 + }
1.80 + if (board[move->fromrow][move->tofile + d] == move->piece) {
1.81 + if (move->fromfile == POS_UNSPECIFIED) {
1.82 + move->fromfile = move->tofile + d;
1.83 + } else {
1.84 + return AMBIGUOUS_MOVE; /* rare situation after promotion */
1.85 + }
1.86 + }
1.87 + return move->fromfile == POS_UNSPECIFIED ?
1.88 + INVALID_POSITION : VALID_MOVE_SYNTAX;
1.89 +}
1.90 +
1.91 +int bishop_getlocation(Board board, Move *move) {
1.92 +
1.93 + if (move->fromfile != POS_UNSPECIFIED) {
1.94 + return bishop_getloc_fixedfile(board, move);
1.95 + }
1.96 +
1.97 + if (move->fromrow != POS_UNSPECIFIED) {
1.98 + return bishop_getloc_fixedrow(board, move);
1.99 + }
1.100 +
1.101 + _Bool amb = 0;
1.102 + for (int d = -7 ; d < 8 ; d++) {
1.103 + uint8_t row = move->torow + d;
1.104 + if (isidx(row)) {
1.105 + uint8_t file = move->tofile + d;
1.106 + if (isidx(file) && board[row][file] == move->piece) {
1.107 + if (amb) {
1.108 + return AMBIGUOUS_MOVE;
1.109 + }
1.110 + amb = 1;
1.111 + move->fromrow = row;
1.112 + move->fromfile = file;
1.113 + }
1.114 + file = move->tofile - d;
1.115 + if (isidx(file) && board[row][file] == move->piece) {
1.116 + if (amb) {
1.117 + return AMBIGUOUS_MOVE;
1.118 + }
1.119 + amb = 1;
1.120 + move->fromrow = row;
1.121 + move->fromfile = file;
1.122 + }
1.123 + }
1.124 + }
1.125 +
1.126 + if (move->fromrow == POS_UNSPECIFIED || move->fromfile == POS_UNSPECIFIED) {
1.127 + return INVALID_POSITION;
1.128 + } else {
1.129 + return VALID_MOVE_SYNTAX;
1.130 + }
1.131 +}
