--- /dev/null
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <errno.h>
+
+#include "hexagon.h"
+
+/*
+ * TODO use binary heap for the openlist and closed list.
+ * open list should be a min-heap on the f value
+ * closed list is just tested for existence, so a sort on
+ * the hex id is fine
+ */
+
+#if 0
+#define DEBUG_ASTAR 1
+#endif
+
+static double default_metric(struct HL_hex a, struct HL_hex b) {
+ return 1.0;
+}
+
+static double default_heuristic(struct HL_hex a, struct HL_hex b) {
+ return (double)HL_distance(a, b);
+}
+
+struct HL_astar *HL_astar_init(struct HL_astar *state) {
+ if (!state) {
+ state = malloc(sizeof *state);
+ if (!state) return NULL;
+ state->malloced = 1;
+ }
+ state->open = 0;
+ state->closed = 0;
+ state->nodes = 0;
+ state->allocated = 0;
+ state->error = 0;
+ state->known = 0;
+ state->index = 0;
+ state->pathlen = 0;
+
+ state->metric = default_metric;
+ state->heuristic = default_heuristic;
+ state->neighbor = HL_adjhexp;
+
+ return state;
+}
+
+/*
+ * Reset a state to enpty.
+ */
+struct HL_astar *HL_astar_clear(struct HL_astar *s) {
+ struct HL_astar_hex *hex;
+ if (!s) return NULL;
+ while (s->open) {
+ hex = s->open->next;
+ free(s->open);
+ s->open = hex;
+ }
+ while (s->closed) {
+ hex = s->closed->next;
+ free(s->closed);
+ s->closed = hex;
+ }
+
+ s->open = 0;
+ s->closed = 0;
+ s->nodes = 0;
+ s->pathlen = 0;
+
+ return s;
+}
+
+void HL_astar_free(struct HL_astar *s) {
+ struct HL_astar_hex *hex;
+ /* free open and closed lists */
+ while (s->open) {
+ hex = s->open->next;
+ free(s->open);
+ s->open = hex;
+ }
+ while (s->closed) {
+ hex = s->closed->next;
+ free(s->closed);
+ s->closed = hex;
+ }
+
+ if (s->malloced) {
+ free(s);
+ }
+}
+
+static struct HL_astar_hex *add_open(struct HL_astar *s, struct HL_hex hex) {
+ struct HL_astar_hex *node;
+#ifdef DEBUG_ASTAR
+ fprintf(stderr, "add to open %d\n", HL_cantor(hex));
+#endif
+
+ if (!s || s->error) {
+#ifdef DEBUG_ASTAR
+ fprintf(stderr, "returning null\n");
+#endif
+
+ return NULL;
+ }
+#ifdef DEBUG_ASTAR
+ fprintf(stderr, "mallocing node(%zd)\n", sizeof *node);
+#endif
+
+ /* TODO check in open or closed */
+ node = malloc(sizeof *node);
+#ifdef DEBUG_ASTAR
+ fprintf(stderr, "add to open %d = %p\n", HL_cantor(hex), node);
+#endif
+
+ node->hex = hex;
+ node->g = 0.0;
+ node->f = 0.0;
+ node->h = 0.0;
+ node->open = 1;
+ node->parent = 0;
+ if (s->open) {
+ s->open->prev = node;
+ }
+ node->next = s->open;
+ node->prev = NULL;
+ s->open = node;
+
+ return node;
+}
+
+static struct HL_astar_hex *closehex(struct HL_astar *s, struct HL_astar_hex *h) {
+ if (!s || s->error) return NULL;
+ if (!h) {
+ s->error = 1;
+ return NULL;
+ }
+
+#ifdef DEBUG_ASTAR
+ fprintf(stderr, "Closing hex: (%d,%d)\n", h->hex.x, h->hex.y);
+#endif
+ h->open = 0;
+ if (h->prev) h->prev->next = h->next;
+ if (h->next) h->next->prev = h->prev;
+ if (s->closed) s->closed->prev = h;
+ if (s->open == h) s->open = h->next;
+ h->next = s->closed;
+ s->closed = h;
+ h->prev = NULL;
+
+ return h;
+}
+
+struct HL_astar_hex *in_closed(struct HL_astar *s, struct HL_hex hex) {
+ struct HL_astar_hex *h;
+ if (!s) return 0;
+
+ for (h = s->closed; h; h = h->next) {
+ if (h->hex.x == hex.x && h->hex.y == hex.y) return h;
+ }
+ return NULL;
+}
+
+struct HL_astar_hex *in_open(struct HL_astar *s, struct HL_hex hex) {
+ struct HL_astar_hex *h;
+ if (!s) return 0;
+
+ for (h = s->open; h; h = h->next) {
+ if (h->hex.x == hex.x && h->hex.y == hex.y) return h;
+ }
+ return NULL;
+}
+
+static struct HL_astar_hex *lowrank(struct HL_astar *s) {
+ struct HL_astar_hex *n, *r;
+
+ if (!s || s->open == 0) return 0;
+
+ r = s->open;
+ for(n = r; n; n = n->next) {
+ if (n->f < r->f) {
+ r = n;
+ }
+ }
+
+ return r;
+}
+
+#ifdef DEBUG_ASTAR
+void dump_list(char *name, struct HL_astar_hex *x) {
+ fprintf(stderr, "%s list: ", name);
+ for(; x; x = x->next) {
+ fprintf(stderr, "(%d,%d)", x->hex.x, x->hex.y);
+ }
+ fprintf(stderr, "\n");
+}
+#endif
+
+/*
+ * find a path from start to end. we use A*
+ */
+int HL_findpath(struct HL_astar *s, int loops) {
+ int dir;
+ struct HL_hex y;
+ struct HL_astar_hex *node, *x, *yopen;
+ int tent_better;
+ double cost;
+
+ s->error = 0;
+
+ if (HL_distance(s->start, s->goal) == 0) return 0;
+
+ node = add_open(s, s->start);
+ node->g = 0.0;
+ node->h = s->heuristic(s->start, s->goal);
+ node->f = node->h;
+
+#ifdef DEBUG_ASTAR
+ fprintf(stderr, "A* findpath: ");
+ fprintf(stderr, "(%d,%d)", s->start.x, s->start.y);
+ fprintf(stderr, " -> ");
+ fprintf(stderr, "(%d,%d)", s->goal.x, s->goal.y);
+ fprintf(stderr, "\n");
+#endif
+
+ while (s->open) {
+
+#ifdef DEBUG_ASTAR
+ dump_list("open", s->open);
+ dump_list("closed", s->closed);
+#endif
+
+ x = lowrank(s);
+#ifdef DEBUG_ASTAR
+ fprintf(stderr, "checking lowest f hex = (%d,%d) f = %f, g = %f, h = %f\n",
+ x->hex.x, x->hex.y,
+ x->f, x->g, x->h
+ );
+#endif
+ if (HL_distance(x->hex, s->goal) == 0) {
+ break;
+ }
+ closehex(s, x);
+
+ int n;
+ for (dir = 0; n = s->neighbor(x->hex, dir, &y),dir<6; dir++) {
+ if (n == 0) continue; /* no hex in that direction */
+ if (in_closed(s, y)) {
+ continue;
+ }
+#ifdef DEBUG_ASTAR
+ fprintf(stderr, "checking dir %d, hex (%d, %d)\n", dir,
+ y.x, y.y);
+#endif
+
+ cost = x->g + s->metric(x->hex, y);
+
+ yopen = in_open(s, y);
+#ifdef DEBUG_ASTAR
+ fprintf(stderr, "checking inopen = %p\n", yopen);
+#endif
+ if (!yopen) {
+ yopen = add_open(s, y);
+ tent_better = 1;
+ } else if (cost < yopen->g) {
+ tent_better = 1;
+ } else {
+ tent_better = 0;
+ }
+
+ if (tent_better) {
+ if (yopen->parent) {
+ if (x->f < yopen->parent->f) {
+ yopen->parent = x;
+ }
+ } else {
+ yopen->parent = x;
+ }
+ yopen->g = cost;
+ yopen->h = s->heuristic(y, s->goal);
+ yopen->f = yopen->g + yopen->h;
+#ifdef DEBUG_ASTAR
+ fprintf(stderr, "maybe better hex = (%d,%d) f = %f, g = %f, h = %f\n",
+ yopen->hex.x, yopen->hex.y,
+ yopen->f, yopen->g, yopen->h
+ );
+#endif
+ }
+ }
+
+ }
+
+ /* error no path ? */
+ if (HL_distance(x->hex, s->goal) != 0) {
+ s->error = 1;
+ return 0;
+ }
+
+#ifdef DEBUG_ASTAR
+ fprintf(stderr, "found path: ");
+#endif
+
+ /* reconstruct path */
+ s->to = x;
+ x->next = 0;
+ for (s->pathlen = 0, yopen = x; yopen; yopen = yopen->parent) {
+ if (yopen->parent) {
+ yopen->parent->next = yopen;
+ }
+ if (HL_distance(yopen->hex, s->start) == 0) s->from = yopen;
+#ifdef DEBUG_ASTAR
+ fprintf(stderr, "(%p %d %d,%d)",
+ yopen, yopen->hex,
+ yopen->hex.x,
+ yopen->hex.y
+ );
+#endif
+ s->pathlen++;
+ };
+ s->pathlen--;
+
+#ifdef DEBUG_ASTAR
+ fprintf(stderr, "\n");
+#endif
+
+ return s->pathlen;
+}
projects / hexagon / blobdiff