universe@10: /*
universe@10:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
universe@10:  *
universe@55:  * Copyright 2016 Mike Becker. All rights reserved.
universe@10:  *
universe@10:  * Redistribution and use in source and binary forms, with or without
universe@10:  * modification, are permitted provided that the following conditions are met:
universe@10:  *
universe@10:  *   1. Redistributions of source code must retain the above copyright
universe@10:  *      notice, this list of conditions and the following disclaimer.
universe@10:  *
universe@10:  *   2. Redistributions in binary form must reproduce the above copyright
universe@10:  *      notice, this list of conditions and the following disclaimer in the
universe@10:  *      documentation and/or other materials provided with the distribution.
universe@10:  *
universe@10:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
universe@10:  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
universe@10:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
universe@10:  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
universe@10:  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
universe@10:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
universe@10:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
universe@10:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
universe@10:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
universe@10:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
universe@10:  * POSSIBILITY OF SUCH DAMAGE.
universe@10:  *
universe@10:  */
universe@10: 
universe@16: #include "rules.h"
universe@10: #include "king.h"
universe@25: #include <stdlib.h>
universe@10: 
universe@25: static _Bool king_castling_chkmoved(GameState *gamestate,
universe@25:     uint8_t row, uint8_t file) {
universe@25:     
universe@25:     MoveList *ml = gamestate->movelist;
universe@25:     while (ml) {
universe@25:         if (ml->move.fromfile == file && ml->move.fromrow == row) {
universe@25:             return 1;
universe@25:         }
universe@25:         ml = ml->next;
universe@25:     }
universe@25:     
universe@19:     return 0;
universe@10: }
universe@10: 
universe@25: _Bool king_chkrules(GameState *gamestate, Move* move) {
universe@25:     if (abs(move->torow - move->fromrow) <= 1 &&
universe@25:         abs(move->tofile - move->fromfile) <= 1) {
universe@25:         return 1;
universe@25:     } else {
universe@25:         /* castling */
universe@25:         if (move->fromrow == move->torow &&
universe@25:             move->fromrow == ((move->piece&COLOR_MASK) == WHITE ? 0 : 7) &&
universe@25:             move->fromfile == fileidx('e') &&
universe@25:             (move->tofile == fileidx('c') || move->tofile == fileidx('g'))) {
universe@25:             
universe@25:             return !king_castling_chkmoved(gamestate,
universe@25:                 move->fromrow, move->fromfile) &&
universe@25:                 !king_castling_chkmoved(gamestate, move->fromrow,
universe@25:                 move->tofile == fileidx('c') ? 0 : 7);
universe@25:         } else {
universe@25:             return 0;
universe@25:         }
universe@25:     }
universe@25: }
universe@25: 
universe@23: _Bool king_isblocked(GameState *gamestate, Move *move) {
universe@25:     
universe@25:     uint8_t opponent_color = opponent_color(move->piece&COLOR_MASK);
universe@25:     
universe@64:     /* being in check does not "block" the king, so don't test it here */
universe@47:     _Bool blocked = 0;
universe@47:     
universe@64:     /* just test, if castling move is blocked */
universe@25:     if (abs(move->tofile - move->fromfile) == 2) {
universe@25:         if (move->tofile == fileidx('c')) {
universe@25:             blocked |= gamestate->board[move->torow][fileidx('b')];
universe@25:         }
universe@25:         uint8_t midfile = (move->tofile+move->fromfile)/2;
universe@25:         blocked |= gamestate->lastmove->move.check ||
universe@25:             gamestate->board[move->torow][midfile] ||
universe@25:             is_covered(gamestate, move->torow, midfile, opponent_color);
universe@25:     }
universe@25:     
universe@25:     return blocked;
universe@10: }