+static game_state *execute_move(game_state *from, char *move)
+{
+ game_state *ret;
+ int x1, x2, y1, y2, xx, yy;
+ int val;
+
+ if (move[0] == 'S' && strlen(move) == from->w * from->h + 1) {
+ int i;
+
+ ret = dup_game(from);
+
+ for (i = 0; i < ret->w * ret->h; i++)
+ ret->grid[i] = (move[i+1] == '1' ? GRID_FULL : GRID_EMPTY);
+
+ ret->completed = ret->cheated = TRUE;
+
+ return ret;
+ } else if ((move[0] == 'F' || move[0] == 'E' || move[0] == 'U') &&
+ sscanf(move+1, "%d,%d,%d,%d", &x1, &y1, &x2, &y2) == 4 &&
+ x1 >= 0 && x2 >= 0 && x1+x2 <= from->w &&
+ y1 >= 0 && y2 >= 0 && y1+y2 <= from->h) {
+
+ x2 += x1;
+ y2 += y1;
+ val = (move[0] == 'F' ? GRID_FULL :
+ move[0] == 'E' ? GRID_EMPTY : GRID_UNKNOWN);
+
+ ret = dup_game(from);
+ for (yy = y1; yy < y2; yy++)
+ for (xx = x1; xx < x2; xx++)
+ ret->grid[yy * ret->w + xx] = val;
+
+ /*
+ * An actual change, so check to see if we've completed the
+ * game.
+ */
+ if (!ret->completed) {
+ int *rowdata = snewn(ret->rowsize, int);
+ int i, len;
+
+ ret->completed = TRUE;
+
+ for (i=0; i<ret->w; i++) {
+ len = compute_rowdata(rowdata,
+ ret->grid+i, ret->h, ret->w);
+ if (len != ret->rowlen[i] ||
+ memcmp(ret->rowdata+i*ret->rowsize, rowdata,
+ len * sizeof(int))) {
+ ret->completed = FALSE;
+ break;
+ }
+ }
+ for (i=0; i<ret->h; i++) {
+ len = compute_rowdata(rowdata,
+ ret->grid+i*ret->w, ret->w, 1);
+ if (len != ret->rowlen[i+ret->w] ||
+ memcmp(ret->rowdata+(i+ret->w)*ret->rowsize, rowdata,
+ len * sizeof(int))) {
+ ret->completed = FALSE;
+ break;
+ }
+ }
+
+ sfree(rowdata);
+ }
+
+ return ret;
+ } else
+ return NULL;
+}
+