diff options
| -rw-r--r-- | pearl.c | 29 |
1 files changed, 29 insertions, 0 deletions
@@ -855,6 +855,35 @@ cleanup: if (ret == 1) assert(b < 0xD); /* we should have had a break by now */ } } + + /* + * Ensure we haven't left the _data structure_ inconsistent, + * regardless of the consistency of the _puzzle_. In + * particular, we should never have marked one square as + * linked to its neighbour if the neighbour is not + * reciprocally linked back to the original square. + * + * This can happen if we get part way through solving an + * impossible puzzle and then give up trying to make further + * progress. So here we fix it up to avoid confusing the rest + * of the game. + */ + for (y = 0; y < h; y++) { + for (x = 0; x < w; x++) { + for (d = 1; d <= 8; d += d) { + int nx = x + DX(d), ny = y + DY(d); + int rlink; + if (0 <= nx && nx < w && 0 <= ny && ny < w) + rlink = result[ny*w+nx] & F(d); + else + rlink = 0; /* off-board squares don't link back */ + + /* If other square doesn't link to us, don't link to it */ + if (!rlink) + result[y*w+x] &= ~d; + } + } + } } sfree(dsfsize); |