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@16: #include "rules.h"
universe@10: #include "rook.h"
universe@10: 
universe@16: _Bool rook_chkrules(Move *move) {
universe@21:     return move->torow == move->fromrow || move->tofile == move->fromfile;
universe@21: }
universe@21: 
universe@23: _Bool rook_isblocked(GameState *gamestate, Move *move) {
universe@21:     
universe@21:     if (move->torow == move->fromrow) {
universe@21:         int d = move->tofile > move->fromfile ? 1 : -1;
universe@21:         uint8_t f = move->fromfile;
universe@21:         while (f != move->tofile-d) {
universe@21:             f += d;
universe@23:             if (gamestate->board[move->fromrow][f]) {
universe@21:                 return 1;
universe@21:             }
universe@21:         }
universe@21:     } else {
universe@21:         int d = move->torow > move->fromrow ? 1 : -1;
universe@21:         uint8_t r = move->fromrow;
universe@21:         while (r != move->torow - d) {
universe@21:             r += d;
universe@23:             if (gamestate->board[r][move->fromfile]) {
universe@21:                 return 1;
universe@21:             }
universe@21:         }
universe@21:     }
universe@21:     
universe@19:     return 0;
universe@10: }
universe@10: 
universe@23: static int rook_getloc_fixedrow(GameState *gamestate, Move *move) {
universe@21:     uint8_t file = POS_UNSPECIFIED;
universe@21:     for (uint8_t f = 0 ; f < 8 ; f++) {
universe@23:         if (gamestate->board[move->fromrow][f] == move->piece) {
universe@21:             if (file == POS_UNSPECIFIED) {
universe@21:                 file = f;
universe@21:             } else {
universe@21:                 return AMBIGUOUS_MOVE;
universe@21:             }
universe@21:         }
universe@21:     }
universe@21:     if (file == POS_UNSPECIFIED) {
universe@21:         return INVALID_POSITION;
universe@21:     } else {
universe@21:         move->fromfile = file;
universe@21:         return VALID_MOVE_SYNTAX;
universe@21:     }
universe@21: }
universe@21: 
universe@23: static int rook_getloc_fixedfile(GameState *gamestate, Move *move) {
universe@21:     uint8_t row = POS_UNSPECIFIED;
universe@21:     for (uint8_t r = 0 ; r < 8 ; r++) {
universe@23:         if (gamestate->board[r][move->fromfile] == move->piece) {
universe@21:             if (row == POS_UNSPECIFIED) {
universe@21:                 row = r;
universe@21:             } else {
universe@21:                 return AMBIGUOUS_MOVE;
universe@21:             }
universe@21:         }   
universe@21:     }
universe@21:     if (row == POS_UNSPECIFIED) {
universe@21:         return INVALID_POSITION;
universe@21:     } else {
universe@21:         move->fromrow = row;
universe@21:         return VALID_MOVE_SYNTAX;
universe@21:     }
universe@10: }
universe@10: 
universe@23: int rook_getlocation(GameState *gamestate, Move *move) {
universe@21:     
universe@21:     if (move->fromfile != POS_UNSPECIFIED) {
universe@21:         if (move->fromfile == move->tofile) {
universe@23:             return rook_getloc_fixedfile(gamestate, move);
universe@21:         } else {
universe@23:             if (gamestate->board[move->torow][move->fromfile] == move->piece) {
universe@21:                 move->fromrow = move->torow;
universe@21:                 return VALID_MOVE_SYNTAX;
universe@21:             } else {
universe@21:                 return INVALID_POSITION;
universe@21:             }
universe@21:         }
universe@21:     }
universe@21:     
universe@21:     if (move->fromrow != POS_UNSPECIFIED) {
universe@21:         if (move->fromrow == move->torow) {
universe@23:             return rook_getloc_fixedrow(gamestate, move);
universe@21:         } else {
universe@23:             if (gamestate->board[move->fromrow][move->tofile] == move->piece) {
universe@21:                 move->fromfile = move->tofile;
universe@21:                 return VALID_MOVE_SYNTAX;
universe@21:             } else {
universe@21:                 return INVALID_POSITION;
universe@21:             }
universe@21:         }
universe@21:     }
universe@21:     
universe@21:     Move chkrowmove = *move, chkfilemove = *move;
universe@21:     
universe@21:     chkrowmove.fromrow = move->torow;
universe@23:     int chkrow = rook_getloc_fixedrow(gamestate, &chkrowmove);
universe@21:     
universe@21:     chkfilemove.fromfile = move->tofile;
universe@23:     int chkfile = rook_getloc_fixedfile(gamestate, &chkfilemove);
universe@21:     
universe@21:     if ((chkrow == VALID_MOVE_SYNTAX && chkfile == VALID_MOVE_SYNTAX) ||
universe@21:         chkrow == AMBIGUOUS_MOVE || chkfile == AMBIGUOUS_MOVE) {
universe@21:         return AMBIGUOUS_MOVE;
universe@21:     }
universe@21:     
universe@21:     if (chkrow == VALID_MOVE_SYNTAX) {
universe@21:         *move = chkrowmove;
universe@21:         return VALID_MOVE_SYNTAX;
universe@21:     }
universe@21:     
universe@21:     if (chkfile == VALID_MOVE_SYNTAX) {
universe@21:         *move = chkfilemove;
universe@21:         return VALID_MOVE_SYNTAX;
universe@21:     }
universe@21:     
universe@21:     return INVALID_POSITION;
universe@10: }