terminal-chess: src/chess/pawn.c@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  */

    30 #include "pawn.h"

    31 #include "rules.h"

    33 _Bool pawn_chkrules(Board board, Move *move) {

    34     int8_t d = ((move->piece & COLOR_MASK) == WHITE ? -1 : 1);

    36     if (move->torow == (d < 0 ? 7 : 0)) {

    37         if (move->promotion) {

    38             uint8_t promopiece = move->promotion & PIECE_MASK;

    39             if (!promopiece || promopiece == PAWN || promopiece == KING) {

    40                 return 0;

    41             }

    42         } else {

    43             return 0;

    44         }

    45     } else {

    46         if (move->promotion) {

    47             return 0;

    48         }

    49     }

    51     if (move->capture) {

    52         if (move->fromrow == move->torow + d && (

    53             move->fromfile == move->tofile + 1 ||

    54             move->fromfile == move->tofile - 1)) {

    56             return mdst(board,move)

    57                 || (board[move->fromrow][move->tofile] & ENPASSANT_THREAT);

    58         } else {

    59             return 0;

    60         }

    61     } else {

    62         if (move->fromfile == move->tofile) {

    63             return (move->fromrow == move->torow + d) ||

    64                 (move->fromrow == (d < 0 ? 1 : 6) && /* advanced first move */

    65                 move->fromrow == move->torow + d*2);

    66         } else {

    67             return 0;

    68         }

    69     }

    70 }

    72 _Bool pawn_isblocked(Board board, Move *move) {

    73     return mdst(board,move) && !move->capture;

    74 }

    76 int pawn_getlocation(Board board, Move *move) {

    77     int8_t d = ((move->piece & COLOR_MASK) == WHITE ? -1 : 1);

    79     if (move->fromfile == POS_UNSPECIFIED) {

    80         move->fromfile = move->tofile;

    81     }

    82     move->fromrow = move->torow + d;

    83     if (move->fromrow > 6) {

    84         return INVALID_POSITION;

    85     } else {

    86         /* advanced first move */

    87         if (move->fromrow == (d < 0 ? 2 : 5) &&

    88             msrc(board,move) != move->piece) {

    90             move->fromrow += d;

    91             if (move->fromrow > 6) {

    92                 return INVALID_POSITION;

    93             }

    94         }

    95     }

    96     return VALID_MOVE_SYNTAX;

    97 }

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