-#ifdef ASTAR
-
-struct astar_hex {
- int hex;
- int f, g, h;
- int parent;
-};
-
-struct astar {
- int open, closed; /* how many in open or closed */
- int closedroom, openroom; /* how much is malloced */
- struct astar_hex *openlist;
- struct astar_hex *closedlist;
- int known, index;
- int error;
-};
-
-static void astar_init(struct astar *state) {
- state->open = 0;
- state->closed = 0;
- state->closedroom = 0;
- state->openroom = 0;
- state->openlist = 0;
- state->closedlist = 0;
- state->error = 0;
- state->known = 0;
- state->index = 0;
-
- return;
-}
-
-static void removeopen(struct astar *s, int hex) {
- int index;
-
- if (s->error) return;
- if (s->open == 0) return;
-
- if (s->known != hex) {
- for (index = 0; index < s->open; index++) {
- if (s->openlist[index].hex == hex) break;
- }
- } else {
- index = s->index;
- s->known = 0; s->index = 0;
- }
- s->openlist[index] = s->openlist[open];
- s->open--;
-}
-
-static void addopen(struct astar *s, int hex) {
- struct astar_hex *mem;
- if (s->error) return;
-
- if (s->open + 1 > s->openroom) {
- mem = realloc(s->openlist, s->openroom * 2 * sizeof *mem);
- if (mem == NULL) {
- s->error = errno;
- return;
- }
- state->openlist = mem;
- s->openroom = s->openroom * 2;
- }
-
- s->openlist[s->open].hex = hex;
- s->openlist[s->open].f = 0;
- s->openlist[s->open].g = 0;
- s->openlist[s->open].h = 0;
- s->known = hex;
- s->index = s->open;
- s->open = s->open + 1;
-}
-
-int lowrank(struct astar *s) {
- int f;
- int hex;
- int i;
-
- if (!s || s->open = 0) return 0;
-
- hex = s->openlist[0].hex;
- f = s->openlist[0].f;
-
- for(i=1; i < s->open; i++) {
- if (s->openlist[i].f < f) {
- hex = s->openlist[i].hex;
- f = s->openlist[i].f;
- }
- /* TODO check s->openlist[i].tiebreak */
- }
-
- return hex;
-}
-
-static int default_metric(int a, int b) {
- return 1;
-}
-
-/*
- * find a path from start to end. we use A*
- */
-int HL_findpath(int start, int end, int psize, int *path,
- double (*metric)(int,int)) {
- int neighbors[6];
- int count;
- int cur = 0;
- struct astar state;
- int neighbor;
-
- if (start == end) return 0;
- if (!metric) metric = default_metric;
-
- astar_init(&state);
- addopen(&state, start);
-
- while (1) {
- cur = lowrank(&state);
- if (cur == end) {
- break;
- }
- addclosed(&state, cur);
- count = HL_hexes_at_range(cur->hex, 1, neighbors, 6);
- for (i=0;i<count;i++) {
- neighbor = neighbors[i];
- cost = g(&state, current) + metric(current, neighbor);
- if (inopen(&state, neighbor) && cost < g(&state, neighbor)) {
- removeopen(&state, neighbor);
- } else
- if (inclosed(&state, neighbor) && cost < g(&state, neighbor)) {
- /* should never happen with
- * admissible heuristic
- */
- removeclosed(&state, neighbor);
- } else
- if (!inopen(&state, neighbor) && !inclosed(&state, neighbor)) {
- addopen(&state, neighbor);
- setg(&state, neighbor, cost);
- setrank(&state, neighbor, cost + h(neighbor,end));
- setparent(&state, neighbor, current);
- } else {
- abort();
- }
- }
- }
-
- count = 0;
- while (parent(&state, cur) != start) {
- count++;
- cur = parent(&state, cur);
- }
- cur = end;
- while (parent(&state, cur) != start) {
- path[count--] = cur;
- cur = parent(&state, cur);
- }
-
-}
-
-#endif
-