universe@10: /*
universe@10:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
universe@10:  *
universe@10:  * Copyright 2014 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@10: #include "pawn.h"
universe@16: #include "rules.h"
universe@10: 
universe@23: _Bool pawn_chkrules(GameState *gamestate, Move *move) {
universe@14:     int8_t d = ((move->piece & COLOR_MASK) == WHITE ? -1 : 1);
universe@18:     
universe@18:     if (move->torow == (d < 0 ? 7 : 0)) {
universe@18:         if (move->promotion) {
universe@18:             uint8_t promopiece = move->promotion & PIECE_MASK;
universe@18:             if (!promopiece || promopiece == PAWN || promopiece == KING) {
universe@19:                 return 0;
universe@18:             }
universe@18:         } else {
universe@19:             return 0;
universe@18:         }
universe@18:     } else {
universe@18:         if (move->promotion) {
universe@19:             return 0;
universe@18:         }
universe@18:     }
universe@18:     
universe@14:     if (move->capture) {
universe@14:         if (move->fromrow == move->torow + d && (
universe@14:             move->fromfile == move->tofile + 1 ||
universe@14:             move->fromfile == move->tofile - 1)) {
universe@15: 
universe@23:             return mdst(gamestate->board, move) ||
universe@23:                 (gamestate->board[move->fromrow][move->tofile]
universe@23:                 & ENPASSANT_THREAT);
universe@14:         } else {
universe@19:             return 0;
universe@14:         }
universe@14:     } else {
universe@14:         if (move->fromfile == move->tofile) {
universe@14:             return (move->fromrow == move->torow + d) ||
universe@14:                 (move->fromrow == (d < 0 ? 1 : 6) && /* advanced first move */
universe@14:                 move->fromrow == move->torow + d*2);
universe@14:         } else {
universe@19:             return 0;
universe@14:         }
universe@14:     }
universe@10: }
universe@10: 
universe@23: _Bool pawn_isblocked(GameState *gamestate, Move *move) {
universe@23:     return mdst(gamestate->board, move) && !move->capture;
universe@10: }
universe@10: 
universe@23: int pawn_getlocation(GameState *gamestate, Move *move) {
universe@10:     int8_t d = ((move->piece & COLOR_MASK) == WHITE ? -1 : 1);
universe@10:     
universe@14:     if (move->fromfile == POS_UNSPECIFIED) {
universe@14:         move->fromfile = move->tofile;
universe@14:     }
universe@10:     move->fromrow = move->torow + d;
universe@10:     if (move->fromrow > 6) {
universe@16:         return INVALID_POSITION;
universe@10:     } else {
universe@10:         /* advanced first move */
universe@10:         if (move->fromrow == (d < 0 ? 2 : 5) &&
universe@23:             msrc(gamestate->board,move) != move->piece) {
universe@10: 
universe@10:             move->fromrow += d;
universe@10:             if (move->fromrow > 6) {
universe@16:                 return INVALID_POSITION;
universe@10:             }
universe@10:         }
universe@10:     }
universe@16:     return VALID_MOVE_SYNTAX;
universe@10: }