*
* ---
*
- * path.c: Empire/A* Interface code.
- * Define AS_STATS for A* statistics.
+ * path.c: Path finding interface code
*
* Known contributors to this file:
* Phil Lapsley, 1991
* Dave Pare, 1991
* Thomas Ruschak, 1993
* Steve McClure, 1997
+ * Markus Armbruster, 2011
*/
#include <config.h>
-#include <stdio.h>
-#include "../as/as.h"
+#include <string.h>
#include "file.h"
-#include "misc.h"
#include "optlist.h"
#include "path.h"
-#include "prototypes.h"
#include "sect.h"
#include "xy.h"
-#define BP_ASHASHSIZE 128 /* A* queue hash table size */
-#define BP_NEIGHBORS 6 /* max number of neighbors */
-
-struct bestp {
- int sctcache_hits;
- int sctcache_misses;
- int bp_mobtype;
- struct as_data *adp;
-};
-
-static int bp_path(struct as_path *pp, char *buf);
-static int bp_neighbors(struct as_coord c, struct as_coord *cp, void *);
-static double bp_lbcost(struct as_coord from, struct as_coord to, void *);
-static double bp_realcost(struct as_coord from, struct as_coord to, void *);
-static double bp_seccost(struct as_coord from, struct as_coord to, void *);
-static int bp_coord_hash(struct as_coord c);
-
-/* We use this for caching neighbors. It never changes except
- * at reboot time (maybe) so we never need to free it */
-static struct sctstr **neighsects;
-
-static struct bestp *
-bp_init(void)
+char *
+BestLandPath(char *path,
+ struct sctstr *from,
+ struct sctstr *to, double *cost, int mob_type)
{
- struct bestp *bp;
+ double c;
+ size_t len;
- bp = malloc(sizeof(*bp));
- memset(bp, 0, sizeof(*bp));
- bp->adp = as_init(BP_NEIGHBORS, BP_ASHASHSIZE, bp_coord_hash,
- bp_neighbors, bp_lbcost, bp_realcost,
- bp_seccost, bp);
+ *cost = 0.0;
+ *path = 0;
- if (bp->adp == NULL)
+ /*
+ * Note: passing from->sct_own for actor is funny, but works: its
+ * only effect is to confine the search to that nation's land. It
+ * doesn't affect mobility costs. The real actor is different for
+ * marching in allied land, and passing it would break path
+ * finding there.
+ */
+ c = path_find(from->sct_x, from->sct_y, to->sct_x, to->sct_y,
+ from->sct_own, mob_type);
+ if (c < 0)
return NULL;
-
- if (neighsects == NULL)
- neighsects = calloc(WORLD_SZ() * 6, sizeof(struct sctstr *));
-
- return bp;
-}
-
-/*
- * Find the best path from sector to to sector, and put the Empire movement
- * string in path. Return 0 on success, -1 on error.
- * FIXME unsafe by design: assumes path[] has space; buffer overrun
- * when path gets long!
- */
-static int
-best_path(struct sctstr *from, struct sctstr *to, char *path, int mob_type)
-{
- static struct bestp *mybestpath;
- struct as_data *adp;
- struct as_path *ap;
-
- if (!mybestpath)
- mybestpath = bp_init();
- adp = mybestpath->adp;
- ap = as_find_cachepath(from->sct_x, from->sct_y, to->sct_x, to->sct_y);
- if (ap == NULL) {
- adp->from.x = from->sct_x;
- adp->from.y = from->sct_y;
- adp->to.x = to->sct_x;
- adp->to.y = to->sct_y;
- mybestpath->bp_mobtype = mob_type;
-
- if (as_search(adp) < 0)
- return -1;
- ap = adp->path;
- }
-
- if (bp_path(ap, path) < 0)
- return -1;
-
-#ifdef AS_STATS
- as_stats(adp, stderr);
-#endif /* AS_STATS */
-#ifdef BP_STATS
- fprintf(stderr, "best path %s\n", path);
- fprintf(stderr, "cache hits/misses: %d/%d\n",
- bp->sctcache_hits, bp->sctcache_misses);
-#endif /* BP_STATS */
- return 0;
-}
-
-/*
- * Translate an A* path into an empire movement string. Return 0 on
- * success, -1 on failure.
- */
-static int
-bp_path(struct as_path *pp, char *buf)
-{
- struct as_path *np;
- char *cp = buf;
- int dx, dy;
- int n;
-
- np = pp->next;
- while (np) {
- dx = np->c.x - pp->c.x;
- /* deal with wraparound from non-neg coords */
- if (dx < -2)
- dx += WORLD_X;
- else if (dx > 2)
- dx -= WORLD_X;
- dy = np->c.y - pp->c.y;
- if (dy < -1)
- dy += WORLD_Y;
- else if (dy > 1)
- dy -= WORLD_Y;
- for (n = 1; n <= 6; n++)
- if (dx == diroff[n][0] && dy == diroff[n][1])
- break;
- if (n > 6)
- return -1;
-
- *cp++ = dirch[n];
- pp = np;
- np = np->next;
- }
- *cp = '\0';
- return 0;
-}
-
-/*
- * Find coords neighboring this sector; return number of such
- * coords, and coordinartes themselves in an array pointed
- * to by *cpp.
- * XXX need to check ownership, sector types, etc.
- */
-static int
-bp_neighbors(struct as_coord c, struct as_coord *cp, void *pp)
-{
- struct sctstr *sectp = (void *)empfile[EF_SECTOR].cache;
- struct bestp *bp = pp;
- coord x, y;
- coord nx, ny;
- int n = 0, i;
- struct sctstr *sp, *from, **ssp;
- /* Six pointers, just in case our cache isn't there */
- struct sctstr *tsp[] = { NULL, NULL, NULL, NULL, NULL, NULL };
- int sx, sy, offset;
-
- x = c.x;
- y = c.y;
- sx = XNORM(x);
- sy = YNORM(y);
- offset = XYOFFSET(sx, sy);
- from = §p[offset];
-
- if (neighsects == NULL)
- ssp = (struct sctstr **)&tsp[0];
- else
- ssp = (struct sctstr **)&neighsects[offset * 6];
- for (i = 1; i <= 6; i++, ssp++) {
- if (*ssp == NULL) {
- /* We haven't cached this neighbor yet */
- nx = x + diroff[i][0];
- ny = y + diroff[i][1];
- sx = XNORM(nx);
- sy = YNORM(ny);
- offset = XYOFFSET(sx, sy);
- sp = §p[offset];
- *ssp = sp;
- } else {
- sp = *ssp;
- sx = XNORM(sp->sct_x);
- sy = YNORM(sp->sct_y);
- }
- /* No need to calculate cost each time, just make sure we can
- move through it. We calculate it later. */
- if (dchr[sp->sct_type].d_mob0 < 0)
- continue;
- if (bp->bp_mobtype == MOB_RAIL && !SCT_HAS_RAIL(sp))
- continue;
- if (sp->sct_own != from->sct_own)
- continue;
- cp[n].x = sx;
- cp[n].y = sy;
- n++;
- }
- return n;
-}
-
-/*
- * Compute a lower-bound on the cost from "from" to "to".
- */
-/*ARGSUSED*/
-static double
-bp_lbcost(struct as_coord from, struct as_coord to, void *pp)
-{
- struct sctstr *sectp = (void *)empfile[EF_SECTOR].cache;
- struct bestp *bp = pp;
- int x, y, sx, sy, offset;
-
- x = to.x;
- y = to.y;
- sx = XNORM(x);
- sy = YNORM(y);
- offset = XYOFFSET(sx, sy);
- return sector_mcost(§p[offset], bp->bp_mobtype);
-}
-
-/*
- * Compute the real cost to move from "from" to "to".
- */
-static double
-bp_realcost(struct as_coord from, struct as_coord to, void *pp)
-{
- return bp_lbcost(from, to, pp);
-}
-
-/*
- * Tie breaker secondary metric (only used when lower bound costs
- * are equal).
- */
-/*ARGSUSED*/
-static double
-bp_seccost(struct as_coord from, struct as_coord to, void *pp)
-{
- return mapdist((coord)from.x, (coord)from.y,
- (coord)to.x, (coord)to.y);
-}
-
-/*
- * Hash a coordinate into an integer.
- */
-static int
-bp_coord_hash(struct as_coord c)
-{
- return ((abs(c.x) + 1) << 3) ^ abs(c.y);
-}
-
-void
-bp_enable_cachepath(void)
-{
- as_enable_cachepath();
-}
-
-void
-bp_disable_cachepath(void)
-{
- as_disable_cachepath();
-}
-
-void
-bp_clear_cachepath(void)
-{
- as_clear_cachepath();
-}
-
-double
-pathcost(struct sctstr *start, char *path, int mob_type)
-{
- struct sctstr *sectp = (void *)empfile[EF_SECTOR].cache;
- unsigned i;
- int o;
- int cx, cy;
- double cost = 0.0;
- struct sctstr *sp;
- int sx, sy, offset;
-
- cx = start->sct_x;
- cy = start->sct_y;
-
- while (*path) {
- if (*path == 'h') {
- path++;
- continue;
- }
- i = *path - 'a';
- if (CANT_HAPPEN(i >= sizeof(dirindex) / sizeof(*dirindex)))
- break;
- o = dirindex[i];
- if (CANT_HAPPEN(o < 0))
- break;
- cx += diroff[o][0];
- cy += diroff[o][1];
- sx = XNORM(cx);
- sy = YNORM(cy);
- offset = XYOFFSET(sx, sy);
- sp = §p[offset];
- cost += sector_mcost(sp, mob_type);
- path++;
- }
-
- return cost;
+ len = path_find_route(path, 1024,
+ from->sct_x, from->sct_y,
+ to->sct_x, to->sct_y);
+ if (len + 1 >= 1024)
+ return NULL;
+ strcpy(path + len, "h");
+ *cost = c;
+ return path;
}
char *
return BestLandPath(path, from, to, cost, MOB_MOVE);
}
-char *
-BestLandPath(char *path,
- struct sctstr *from,
- struct sctstr *to, double *cost, int mob_type)
-{
- int length;
-
- *path = 0;
- *cost = 0.0;
- if (best_path(from, to, path, mob_type) < 0)
- return NULL;
- *cost = pathcost(from, path, mob_type);
- length = strlen(path);
- path[length] = 'h';
- path[length + 1] = '\0';
- return path;
-}
-
char *
BestShipPath(char *path, int fx, int fy, int tx, int ty, int owner)
{
projects / empserver / blobdiff