terminal-chess: src/chess/rook.c@824c9522ce66

     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 "rules.h"

    31 #include "rook.h"

    33 _Bool rook_chkrules(Move *move) {

    34     return move->torow == move->fromrow || move->tofile == move->fromfile;

    35 }

    37 _Bool rook_isblocked(GameState *gamestate, Move *move) {

    39     if (move->torow == move->fromrow) {

    40         int d = move->tofile > move->fromfile ? 1 : -1;

    41         uint8_t f = move->fromfile;

    42         while (f != move->tofile-d) {

    43             f += d;

    44             if (gamestate->board[move->fromrow][f]) {

    45                 return 1;

    46             }

    47         }

    48     } else {

    49         int d = move->torow > move->fromrow ? 1 : -1;

    50         uint8_t r = move->fromrow;

    51         while (r != move->torow - d) {

    52             r += d;

    53             if (gamestate->board[r][move->fromfile]) {

    54                 return 1;

    55             }

    56         }

    57     }

    59     return 0;

    60 }

    62 static int rook_getloc_fixedrow(GameState *gamestate, Move *move) {

    63     uint8_t file = POS_UNSPECIFIED;

    64     for (uint8_t f = 0 ; f < 8 ; f++) {

    65         if (gamestate->board[move->fromrow][f] == move->piece) {

    66             if (file == POS_UNSPECIFIED) {

    67                 file = f;

    68             } else {

    69                 return AMBIGUOUS_MOVE;

    70             }

    71         }

    72     }

    73     if (file == POS_UNSPECIFIED) {

    74         return INVALID_POSITION;

    75     } else {

    76         move->fromfile = file;

    77         return VALID_MOVE_SYNTAX;

    78     }

    79 }

    81 static int rook_getloc_fixedfile(GameState *gamestate, Move *move) {

    82     uint8_t row = POS_UNSPECIFIED;

    83     for (uint8_t r = 0 ; r < 8 ; r++) {

    84         if (gamestate->board[r][move->fromfile] == move->piece) {

    85             if (row == POS_UNSPECIFIED) {

    86                 row = r;

    87             } else {

    88                 return AMBIGUOUS_MOVE;

    89             }

    90         }

    91     }

    92     if (row == POS_UNSPECIFIED) {

    93         return INVALID_POSITION;

    94     } else {

    95         move->fromrow = row;

    96         return VALID_MOVE_SYNTAX;

    97     }

    98 }

   100 int rook_getlocation(GameState *gamestate, Move *move) {

   102     if (move->fromfile != POS_UNSPECIFIED) {

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

   104             return rook_getloc_fixedfile(gamestate, move);

   105         } else {

   106             if (gamestate->board[move->torow][move->fromfile] == move->piece) {

   107                 move->fromrow = move->torow;

   108                 return VALID_MOVE_SYNTAX;

   109             } else {

   110                 return INVALID_POSITION;

   111             }

   112         }

   113     }

   115     if (move->fromrow != POS_UNSPECIFIED) {

   116         if (move->fromrow == move->torow) {

   117             return rook_getloc_fixedrow(gamestate, move);

   118         } else {

   119             if (gamestate->board[move->fromrow][move->tofile] == move->piece) {

   120                 move->fromfile = move->tofile;

   121                 return VALID_MOVE_SYNTAX;

   122             } else {

   123                 return INVALID_POSITION;

   124             }

   125         }

   126     }

   128     Move chkrowmove = *move, chkfilemove = *move;

   130     chkrowmove.fromrow = move->torow;

   131     int chkrow = rook_getloc_fixedrow(gamestate, &chkrowmove);

   133     chkfilemove.fromfile = move->tofile;

   134     int chkfile = rook_getloc_fixedfile(gamestate, &chkfilemove);

   136     if ((chkrow == VALID_MOVE_SYNTAX && chkfile == VALID_MOVE_SYNTAX) ||

   137         chkrow == AMBIGUOUS_MOVE || chkfile == AMBIGUOUS_MOVE) {

   138         return AMBIGUOUS_MOVE;

   139     }

   141     if (chkrow == VALID_MOVE_SYNTAX) {

   142         *move = chkrowmove;

   143         return VALID_MOVE_SYNTAX;

   144     }

   146     if (chkfile == VALID_MOVE_SYNTAX) {

   147         *move = chkfilemove;

   148         return VALID_MOVE_SYNTAX;

   149     }

   151     return INVALID_POSITION;

   152 }

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