return ret;
}
+/*
+ * Return values: -1 means puzzle was proved inconsistent, 0 means we
+ * failed to narrow down to a unique solution, +1 means we solved it
+ * fully.
+ */
static int net_solver(int w, int h, unsigned char *tiles,
unsigned char *barriers, int wrapping)
{
#endif
}
- assert(j > 0); /* we can't lose _all_ possibilities! */
+ if (j == 0) {
+ /* If we've ruled out all possible orientations for a
+ * tile, then our puzzle has no solution at all. */
+ return -1;
+ }
if (j < i) {
done_something = TRUE;
/*
* Mark all completely determined tiles as locked.
*/
- j = TRUE;
+ j = +1;
for (i = 0; i < w*h; i++) {
if (tilestate[i * 4 + 1] == 255) {
assert(tilestate[i * 4 + 0] != 255);
tiles[i] = tilestate[i * 4] | LOCKED;
} else {
tiles[i] &= ~LOCKED;
- j = FALSE;
+ j = 0;
}
}
/*
* Run the solver to check unique solubility.
*/
- while (!net_solver(w, h, tiles, NULL, params->wrapping)) {
+ while (net_solver(w, h, tiles, NULL, params->wrapping) != 1) {
int n = 0;
/*
* Run the internal solver on the provided grid. This might
* not yield a complete solution.
*/
+ int solver_result;
+
memcpy(tiles, state->tiles, state->width * state->height);
- net_solver(state->width, state->height, tiles,
- state->barriers, state->wrapping);
+ solver_result = net_solver(state->width, state->height, tiles,
+ state->barriers, state->wrapping);
+
+ if (solver_result < 0) {
+ *error = "No solution exists for this puzzle";
+ sfree(tiles);
+ return NULL;
+ }
} else {
for (i = 0; i < state->width * state->height; i++) {
int c = aux[i];
const struct game thegame = {
"Net", "games.net", "net",
default_params,
- game_fetch_preset,
+ game_fetch_preset, NULL,
decode_params,
encode_params,
free_params,