* Markus Armbruster, 2011
*/
+/*
+ * Define AS_STATS for A* statistics on stderr.
+ *
+ * Define AS_NO_PATH_CACHE to disable the path cache. The path cache
+ * saves a lot of work, but uses lots of memory. It should be a
+ * significant net win, unless you run out of memory.
+ *
+ * Define AS_NO_NEIGHBOR_CACHE to disable the neighbor cache. The
+ * neighbor cache trades a modest amount of memory to save a bit of
+ * work. In its current form, it doesn't really make a difference.
+ */
+
#include <config.h>
#include <string.h>
+#include "../as/as.h"
#include "file.h"
#include "optlist.h"
#include "path.h"
+#include "prototypes.h"
#include "sect.h"
#include "xy.h"
+#ifdef USE_PATH_FIND
+void
+bp_enable_cachepath(void)
+{
+}
+
+void
+bp_disable_cachepath(void)
+{
+}
+
+void
+bp_clear_cachepath(void)
+{
+}
+
char *
BestLandPath(char *path,
struct sctstr *from,
strcpy(path, "h");
return path;
}
+#else /* !USE_PATH_FIND */
+#define BP_ASHASHSIZE 128 /* A* queue hash table size */
+#define BP_NEIGHBORS 6 /* max number of neighbors */
+
+struct bestp {
+ 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)
+{
+ struct bestp *bp;
+
+ 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);
+
+ if (bp->adp == NULL)
+ return NULL;
+
+#ifndef AS_NO_NEIGHBOR_CACHE
+ if (neighsects == NULL)
+ neighsects = calloc(WORLD_SZ() * 6, sizeof(struct sctstr *));
+#endif
+
+ 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;
+ int res;
+
+ if (!mybestpath)
+ mybestpath = bp_init();
+ adp = mybestpath->adp;
+#ifdef AS_NO_PATH_CACHE
+ ap = NULL;
+#else
+ ap = as_find_cachepath(from->sct_x, from->sct_y, to->sct_x, to->sct_y);
+#endif
+ 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;
+
+ res = as_search(adp);
+#ifdef AS_STATS
+ as_stats(adp, stderr);
+#ifndef AS_NO_NEIGHBOR_CACHE
+ fprintf(stderr, "neighbor cache %zu bytes\n",
+ WORLD_SZ() * 6 * sizeof(struct sctstr *));
+#endif
+#endif
+ if (res < 0)
+ return -1;
+ ap = adp->path;
+ }
+
+ if (bp_path(ap, path) < 0)
+ return -1;
+ 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 = sp->sct_x;
+ sy = 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)
+{
+#ifndef AS_NO_PATH_CACHE
+ as_enable_cachepath();
+#endif
+}
+
+void
+bp_disable_cachepath(void)
+{
+#ifndef AS_NO_PATH_CACHE
+ as_disable_cachepath();
+#endif
+}
+
+void
+bp_clear_cachepath(void)
+{
+#ifndef AS_NO_PATH_CACHE
+ as_clear_cachepath();
+#endif
+}
+
+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;
+}
+
+char *
+BestDistPath(char *path,
+ struct sctstr *from,
+ struct sctstr *to, double *cost)
+{
+ 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)
+{
+ char *map;
+
+ map = ef_ptr(EF_BMAP, owner);
+ if (!map)
+ return NULL;
+ return bestownedpath(path, map, fx, fy, tx, ty, owner);
+}
+
+char *
+BestAirPath(char *path, int fx, int fy, int tx, int ty)
+{
+ return bestownedpath(path, NULL, fx, fy, tx, ty, -1);
+}
+#endif /* !USE_PATH_FIND */
projects / empserver / blobdiff