+static game_state *solve_game(game_state *state, game_aux_info *aux,
+ char **error)
+{
+ game_state *ret;
+ int c = state->c, r = state->r;
+ int rsolve_ret;
+
+ /*
+ * I could have stored the grid I invented in the game_aux_info
+ * and extracted it here where available, but it seems easier
+ * just to run my internal solver in all cases.
+ */
+
+ ret = dup_game(state);
+ ret->completed = ret->cheated = TRUE;
+
+ rsolve_ret = rsolve(c, r, ret->grid, NULL, 2);
+
+ if (rsolve_ret != 1) {
+ free_game(ret);
+ if (rsolve_ret == 0)
+ *error = "No solution exists for this puzzle";
+ else
+ *error = "Multiple solutions exist for this puzzle";
+ return NULL;
+ }
+
+ return ret;
+}
+
+static char *grid_text_format(int c, int r, digit *grid)
+{
+ int cr = c*r;
+ int x, y;
+ int maxlen;
+ char *ret, *p;
+
+ /*
+ * There are cr lines of digits, plus r-1 lines of block
+ * separators. Each line contains cr digits, cr-1 separating
+ * spaces, and c-1 two-character block separators. Thus, the
+ * total length of a line is 2*cr+2*c-3 (not counting the
+ * newline), and there are cr+r-1 of them.
+ */
+ maxlen = (cr+r-1) * (2*cr+2*c-2);
+ ret = snewn(maxlen+1, char);
+ p = ret;
+
+ for (y = 0; y < cr; y++) {
+ for (x = 0; x < cr; x++) {
+ int ch = grid[y * cr + x];
+ if (ch == 0)
+ ch = ' ';
+ else if (ch <= 9)
+ ch = '0' + ch;
+ else
+ ch = 'a' + ch-10;
+ *p++ = ch;
+ if (x+1 < cr) {
+ *p++ = ' ';
+ if ((x+1) % r == 0) {
+ *p++ = '|';
+ *p++ = ' ';
+ }
+ }
+ }
+ *p++ = '\n';
+ if (y+1 < cr && (y+1) % c == 0) {
+ for (x = 0; x < cr; x++) {
+ *p++ = '-';
+ if (x+1 < cr) {
+ *p++ = '-';
+ if ((x+1) % r == 0) {
+ *p++ = '+';
+ *p++ = '-';
+ }
+ }
+ }
+ *p++ = '\n';
+ }
+ }
+
+ assert(p - ret == maxlen);
+ *p = '\0';
+ return ret;
+}
+
+static char *game_text_format(game_state *state)
+{
+ return grid_text_format(state->c, state->r, state->grid);
+}
+