sokoban.c

#include <stdio.h>
#include <stdlib.h>

#define EMPTY   0x00
#define PLAYER  0x01
#define BOX     0x02
#define TARGET  0x04
#define OUTSIDE 0xf0

#define MATCH(x, bits) ((x & bits) == bits)
#define AVAILABLE(x) (!MATCH(x, OUTSIDE) && !MATCH(x, BOX))

#define MAX_WIDTH  10
#define MAX_HEIGTH 10

int WIDTH, HEIGTH;

#define POS(x, y) (y * MAX_WIDTH + x)
#define X(pos)    (pos % MAX_WIDTH + 1)
#define Y(pos)    (pos / MAX_WIDTH + 1)
#define END 987654321

int posx, posy;
int board[MAX_WIDTH + 4][MAX_HEIGTH + 4];

void reset_board(int *boxes, int *targets, int *blocks) {
    int i, j, pos;
    for(i = 0; i < MAX_WIDTH+4; i++) {
        for(j = 0; j < MAX_HEIGTH+4; j++) {
            board[i][j] = OUTSIDE;
            if(2 <= i && i < WIDTH+2 && 2 <= j && j < HEIGTH+2) board[i][j] = EMPTY;
        }
    }
    for(i = 0; boxes[i] != END; i++) { int pos = boxes[i]; board[X(pos)][Y(pos)] = BOX; }
    for(i = 0; targets[i] != END; i++) { int pos = targets[i]; board[X(pos)][Y(pos)] |= TARGET; }
    for(i = 0; blocks[i] != END; i++) { int pos = blocks[i]; board[X(pos)][Y(pos)] |= OUTSIDE; }

    for(i = 2; i < WIDTH+2; i++) for(j = 2; j < HEIGTH+2; j++) {
        if(board[i][j] == EMPTY) { posx = i; posy = j; return; }
    }

    for(i = 2; i < WIDTH+2; i++) for(j = 2; j < HEIGTH+2; j++) {
        if(board[i][j] == TARGET) { posx = i; posy = j; return; }
    }

    fprintf(stderr, "no empty spaces!\n");
    exit(1);
}

int win_yet() {
    int i, j, tmp;
    for(j = 2; j < HEIGTH+2; j++) {
        for(i = 2; i < WIDTH+2; i++) {
            tmp = board[i][j];
            if(MATCH(tmp, TARGET) && !MATCH(tmp, BOX)) return 0;
        }
    }
    return 1;
}


#define OUTPUT(ch, attr) do {                             \
    if(attr != a) { printf("\x1b[%dm", attr); a = attr; } \
    printf("%c", ch);                                     \
    } while(0)

void draw_board() {
    int i, j, x;
    int a = 0, a_ = 0;

    OUTPUT('\r', 0); OUTPUT('\n', 0);

    for(j = 2; j < HEIGTH+2; j++) {
        OUTPUT(' ', 0);
        for(i = 2; i < WIDTH+2; i++) {
            x = board[i][j];
            if(i == posx && j == posy) OUTPUT('@', 36);
            else if(MATCH(x,OUTSIDE))  OUTPUT('=', 36);
            else if(MATCH(x, BOX))     OUTPUT('#', 33);
            else if(MATCH(x, TARGET))  OUTPUT('$', 35);
            else if(x == EMPTY)        OUTPUT('.', 0);
            else OUTPUT('?', 41);
        }
        OUTPUT('\r', 0);
        OUTPUT('\n', 0);
    }
    return;
}

enum { North, South, East, West, Nowhere };

void step(int x, int y, int dir) {
    int nx = x, ny = y;
    int nnx = x, nny = y;
    int t, s;

    if(dir == North) { ny--; nny -= 2; }
    if(dir == South) { ny++; nny += 2; }
    if(dir == East)  { nx++; nnx += 2; }
    if(dir == West)  { nx--; nnx -= 2; }

    t = board[nx][ny];
    s = board[nnx][nny];

    if(AVAILABLE(t)) { posx = nx; posy = ny; return; }

    if(MATCH(t, BOX) && AVAILABLE(s)) {
        t ^= BOX; board[nx][ny]   = t;
        s ^= BOX; board[nnx][nny] = s;
        posx = nx; posy = ny; return;
    }

    return;
}


int main() {
    int boxes[]   = { POS(3, 2), POS(4, 2), POS(2, 3), POS(2, 4), END };
    int targets[] = { POS(3, 3), POS(4, 3), POS(3, 4), POS(4, 4), END };
    int blocks[] = { END };

    WIDTH  = 5;
    HEIGTH = 5;
    reset_board(boxes, targets, blocks);
    draw_board();

    int c = getc(stdin);
    while(c != EOF) {
        int dir = Nowhere;
        switch(c) {
            //case '\n': draw_board(); break;

            case '!': printf("goodbye\r\n"); exit(0); break;

            case 'q': printf("starting over...\r\n");
                      reset_board(boxes, targets, blocks);
                      break;

            default: printf("direction? [n, s, e, w]\r\n"); break;

            case 'n': case 'A': dir = North; break;
            case 's': case 'B': dir = South; break;
            case 'e': case 'C': dir = East; break;
            case 'w': case 'D': dir = West; break;
        };

        step(posx, posy, dir);
        if(win_yet()) {
            draw_board();
            printf("you win!\r\n");
            exit(0);
        }
        draw_board();
        c = getc(stdin);
    }
    return 0;
}