Mercurial > hg > terminal-chess / file revision

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2016 Mike Becker. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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 */

#include "pawn.h"
#include "rules.h"

bool pawn_chkrules(GameState *gamestate, Move *move) {
    int8_t d = piece_color(move->piece) == WHITE ? -1 : 1;
    
    if (move->torow == (d < 0 ? 7 : 0)) {
        if (move->promotion) {
            unsigned ppiecetype = piece_type(move->promotion);
            if (!ppiecetype || ppiecetype == PAWN || ppiecetype == KING) {
                return false;
            }
        } else {
            return false;
        }
    } else {
        if (move->promotion) {
            return false;
        }
    }
    
    if (move->capture) {
        if (move->fromrow == move->torow + d && (
            move->fromfile == move->tofile + 1 ||
            move->fromfile == move->tofile - 1)) {

            return piece_at(gamestate, mdst(move)) ||
                enpassant_threat_exists(gamestate, move->fromrow, move->tofile);
        } else {
            return false;
        }
    } else {
        if (move->fromfile == move->tofile) {
            return (move->fromrow == move->torow + d) ||
                (move->fromrow == (d < 0 ? 1 : 6) && /* advanced first move */
                move->fromrow == move->torow + d*2);
        } else {
            return false;
        }
    }
}

bool pawn_isblocked(GameState *gamestate, Move *move) {
    if (move->torow == move->fromrow + 1 || move->torow == move->fromrow - 1) {
        return piece_at(gamestate, mdst(move)) && !move->capture;
    } else {
        return piece_at(gamestate, mdst(move)) ||
            gamestate->board[(move->fromrow+move->torow)/2][move->tofile];
    }
}