path: root/mbbsd/chc_rule.c

/* $Id: chc_rule.c,v 1.4 2002/07/21 09:26:02 in2 Exp $ */
#include "bbs.h"

#define CENTER(a, b)      (((a) + (b)) >> 1)

void
chc_init_board(board_t board)
{
    memset(board, 0, sizeof(board_t));
    board[0][4] = CHE(1, chc_my ^ 1);   /* 將 */
    board[0][3] = board[0][5] = CHE(2, chc_my ^ 1); /* 士 */
    board[0][2] = board[0][6] = CHE(3, chc_my ^ 1); /* 象 */
    board[0][0] = board[0][8] = CHE(4, chc_my ^ 1); /* 車 */
    board[0][1] = board[0][7] = CHE(5, chc_my ^ 1); /* 馬 */
    board[2][1] = board[2][7] = CHE(6, chc_my ^ 1); /* 包 */
    board[3][0] = board[3][2] = board[3][4] =
    board[3][6] = board[3][8] = CHE(7, chc_my ^ 1); /* 卒 */

    board[9][4] = CHE(1, chc_my);   /* 帥 */
    board[9][3] = board[9][5] = CHE(2, chc_my); /* 仕 */
    board[9][2] = board[9][6] = CHE(3, chc_my); /* 相 */
    board[9][0] = board[9][8] = CHE(4, chc_my); /* 車 */
    board[9][1] = board[9][7] = CHE(5, chc_my); /* 傌 */
    board[7][1] = board[7][7] = CHE(6, chc_my); /* 炮 */
    board[6][0] = board[6][2] = board[6][4] =
    board[6][6] = board[6][8] = CHE(7, chc_my); /* 兵 */
}

void
chc_movechess(board_t board)
{
    board[chc_to.r][chc_to.c] = board[chc_from.r][chc_from.c];
    board[chc_from.r][chc_from.c] = 0;
}

static int
dist(rc_t from, rc_t to, int rowcol)
{
    int             d;

    d = rowcol ? from.c - to.c : from.r - to.r;
    return d > 0 ? d : -d;
}

static int
between(board_t board, rc_t from, rc_t to, int rowcol)
{
    int             i, rtv = 0;

    if (rowcol) {
    if (from.c > to.c)
        i = from.c, from.c = to.c, to.c = i;
    for (i = from.c + 1; i < to.c; i++)
        if (board[to.r][i])
        rtv++;
    } else {
    if (from.r > to.r)
        i = from.r, from.r = to.r, to.r = i;
    for (i = from.r + 1; i < to.r; i++)
        if (board[i][to.c])
        rtv++;
    }
    return rtv;
}

int
chc_canmove(board_t board, rc_t from, rc_t to)
{
    int             i;
    int             rd, cd, turn;

    rd = dist(from, to, 0);
    cd = dist(from, to, 1);
    turn = CHE_O(board[from.r][from.c]);

    /* general check */
    if (board[to.r][to.c] && CHE_O(board[to.r][to.c]) == turn)
    return 0;

    /* individual check */
    switch (CHE_P(board[from.r][from.c])) {
    case 1:         /* 將 帥 */
    if (!(rd == 1 && cd == 0) &&
        !(rd == 0 && cd == 1))
        return 0;
    if ((turn == (chc_my ^ 1) && to.r > 2) ||
        (turn == chc_my && to.r < 7) ||
        to.c < 3 || to.c > 5)
        return 0;
    break;
    case 2:         /* 士 仕 */
    if (!(rd == 1 && cd == 1))
        return 0;
    if ((turn == (chc_my ^ 1) && to.r > 2) ||
        (turn == chc_my && to.r < 7) ||
        to.c < 3 || to.c > 5)
        return 0;
    break;
    case 3:         /* 象 相 */
    if (!(rd == 2 && cd == 2))
        return 0;
    if ((turn == (chc_my ^ 1) && to.r > 4) ||
        (turn == chc_my && to.r < 5))
        return 0;
    /* 拐象腿 */
    if (board[CENTER(from.r, to.r)][CENTER(from.c, to.c)])
        return 0;
    break;
    case 4:         /* 車 */
    if (!(rd > 0 && cd == 0) &&
        !(rd == 0 && cd > 0))
        return 0;
    if (between(board, from, to, rd == 0))
        return 0;
    break;
    case 5:         /* 馬 傌 */
    if (!(rd == 2 && cd == 1) &&
        !(rd == 1 && cd == 2))
        return 0;
    /* 拐馬腳 */
    if (rd == 2) {
        if (board[CENTER(from.r, to.r)][from.c])
        return 0;
    } else {
        if (board[from.r][CENTER(from.c, to.c)])
        return 0;
    }
    break;
    case 6:         /* 包 炮 */
    if (!(rd > 0 && cd == 0) &&
        !(rd == 0 && cd > 0))
        return 0;
    i = between(board, from, to, rd == 0);
    if ((i > 1) ||
        (i == 1 && !board[to.r][to.c]) ||
        (i == 0 && board[to.r][to.c]))
        return 0;
    break;
    case 7:         /* 卒 兵 */
    if (!(rd == 1 && cd == 0) &&
        !(rd == 0 && cd == 1))
        return 0;
    if (((turn == (chc_my ^ 1) && to.r < 5) ||
         (turn == chc_my && to.r > 4)) &&
        cd != 0)
        return 0;
    if ((turn == (chc_my ^ 1) && to.r < from.r) ||
        (turn == chc_my && to.r > from.r))
        return 0;
    break;
    }
    return 1;
}

static void
findking(board_t board, int turn, rc_t * buf)
{
    int             i, r, c;

    r = (turn == (chc_my ^ 1)) ? 0 : 7;
    for (i = 0; i < 3; r++, i++)
    for (c = 3; c < 6; c++)
        if (CHE_P(board[r][c]) == 1 &&
        CHE_O(board[r][c]) == turn) {
        buf->r = r, buf->c = c;
        return;
        }
}

int
chc_iskfk(board_t board)
{
    rc_t            from, to;

    findking(board, 0, &to);
    findking(board, 1, &from);
    if (from.c == to.c && between(board, from, to, 0) == 0)
    return 1;
    return 0;
}

int
chc_ischeck(board_t board, int turn)
{
    rc_t            from, to;

    findking(board, turn, &to);
    for (from.r = 0; from.r < BRD_ROW; from.r++)
    for (from.c = 0; from.c < BRD_COL; from.c++)
        if (board[from.r][from.c] &&
        CHE_O(board[from.r][from.c]) != turn)
        if (chc_canmove(board, from, to))
            return 1;
    return 0;
}