diff options
| -rw-r--r-- | 22.c | 110 |
1 files changed, 110 insertions, 0 deletions
@@ -147,6 +147,27 @@ faceid_orientation(int topid, int destid, enum direction destdir) } +int +mymemswap(void * a, void * b, size_t len) +{ + char tmp[BUFSIZ]; + + if (a == b) + return 0; + + while (len > 0) { + size_t chunk = len < sizeof(tmp) ? len : sizeof(tmp); + + memcpy(tmp, a, chunk); + memcpy(a, b, chunk); + memcpy(b, tmp, chunk); + len -= chunk; + } + + return 0; +} + + struct point { int x; int y; @@ -195,9 +216,75 @@ struct map { int map_elem(struct map const * map, int x, int y); +struct face const * map_face_at(struct map const * map, int x, int y); + int map_outline(struct point ** outline, struct map const * map); +static +int +map__init_faces_reorder(struct map * map, struct face const * face, struct face const * from) +{ + static enum direction const dirs[] = { D_NORTH, D_WEST, D_SOUTH, D_EAST }; + + int fsrcid, dir; + + fsrcid = face - map->faces; + + for (dir = 0; dir < 4; ++dir) { + struct face * nbr; + int nbrid; + + // Get the neighbour in the net in one of the directions + switch (dirs[dir]) { + case D_NORTH: + nbr = (struct face *) map_face_at(map, face->vertices[3].x, face->vertices[3].y); + break; + + case D_WEST: + nbr = (struct face *) map_face_at(map, face->vertices[0].x - 1, face->vertices[0].y); + break; + + case D_SOUTH: + nbr = (struct face *) map_face_at(map, face->vertices[0].x, face->vertices[0].y - 1); + break; + + case D_EAST: + nbr = (struct face *) map_face_at(map, face->vertices[1].x, face->vertices[1].y); + break; + + default: + nbr = NULL; + break; + } + + if (!nbr) + // There is no neighbour in the net at that location. + continue; + if (nbr == from) + // The neighbour is the face that told us to rearrange + // our neighbours. Do nothing. + continue; + + // Find the id of the neighbour + nbrid = faceid_look(fsrcid, face->dir, dirs[dir]); + + // Move the face into the right position in faces[] + mymemswap(map->faces + nbrid, nbr, sizeof(struct face)); + nbr = map->faces + nbrid; + + // Set its direction. + nbr->dir = faceid_orientation(nbrid, fsrcid, dirs[(dir + 2) % 4]); + + // And reorder the faces around it + map__init_faces_reorder(map, nbr, face); + } + + return 0; +} + + +static int map__init_faces(struct map * map) { @@ -269,6 +356,11 @@ map__init_faces(struct map * map) return -1; } + // Reorder the faces around face 0, so that each face is in the right + // place in the faces[] array, and oriented appropriately, according + // to faceids[] + map__init_faces_reorder(map, map->faces + 0, NULL); + free(outline); return 0; } @@ -354,6 +446,24 @@ map_elem(struct map const * map, int x, int y) } +// Get the face at a particular x,y co-ordinate +struct face const * +map_face_at(struct map const * map, int x, int y) +{ + struct face const * face; + + if (map->type != M_NET) + return NULL; + + for (face = map->faces; face < map->faces + 6; ++face) + if (x >= face->vertices[0].x && x < face->vertices[2].x + && y >= face->vertices[0].y && y < face->vertices[2].y) + return face; + + return NULL; +} + + // Get the outline of the map, anti-clockwise // // Note that for lengths to be correct, as we're tracing south and east we keep |