Use sctstr member sct_uid instead of recomputing it

The old code recomputed it with sctoff() in some places, without
checking for failure.  Not a bug, because it can't actually fail, just
confusing.

include/sect.h

@@ -158,7 +158,7 @@ struct dchrstr {
 #define SCT_TYPE_MAX    38
 
 #define getsect(x, y, p) ef_read(EF_SECTOR, sctoff((x), (y)), (p))
-#define putsect(p) ef_write(EF_SECTOR, sctoff((p)->sct_x, (p)->sct_y), (p))
+#define putsect(p) ef_write(EF_SECTOR, (p)->sct_uid, (p))
 #define getsectp(x, y) (struct sctstr *)ef_ptr(EF_SECTOR, sctoff((x), (y)))
 #define getsectid(id) (struct sctstr *)ef_ptr(EF_SECTOR, (id))
 

src/lib/commands/bdes.c

@@ -53,7 +53,7 @@ bdes(void)
     while (!player->aborted && nxtsct(&nstr, &sect)) {
 	if ((nstr.ncond > 0) && (sect.sct_own != player->cnum))
 	    continue;
-	d = player->map[sctoff(nstr.x, nstr.y)];
+	d = player->map[sect.sct_uid];
 	sprintf(prompt, "%s '%c'  desig? ",
 		xyas(nstr.x, nstr.y, player->cnum),
 		d ? d : ' ');

src/lib/commands/navi.c

@@ -327,7 +327,7 @@ nav_map(int x, int y, int show_designations)
 	 * in which case they'll see that.
 	 * --ts
 	 */
-	*ptr = player->bmap[sctoff(sect.sct_x, sect.sct_y)];
+	*ptr = player->bmap[sect.sct_uid];
     }
     if (changed)
 	writemap(player->cnum);

src/lib/common/bestpath.c

@@ -221,6 +221,6 @@ owned_and_navigable(char *bigmap, int x, int y, int own)
     }
 
     /* Can only check bigmap */
-    mapspot = bigmap[sctoff(x, y)];
+    mapspot = bigmap[sect.sct_uid];
     return mapspot == '.' || mapspot == ' ' || mapspot == 0;
 }

src/lib/subs/maps.c

@@ -431,9 +431,9 @@ share_bmap(natid from, natid to, struct nstr_sect *ns, char des,
 	from_des &= ~0x20;
 
     while (nxtsct(ns, &sect)) {
-	if (!(fromdes = from_bmap[sctoff(ns->x, ns->y)]))
+	if (!(fromdes = from_bmap[sect.sct_uid]))
 	    continue;
-	todes = to_bmap[sctoff(ns->x, ns->y)];
+	todes = to_bmap[sect.sct_uid];
 	if (todes &&
 	    todes != '?' &&
 	    todes != '.' && todes != ' ' && todes != from_des)

src/lib/subs/move.c

@@ -300,7 +300,7 @@ fly_map(coord curx, coord cury)
     i = 0;
     while (i < 7 && nxtsct(&ns, &sect)) {
 	/* Nasty: this relies on the iteration order */
-	if (!(view[i] = player->bmap[sctoff(ns.x, ns.y)]))
+	if (!(view[i] = player->bmap[sect.sct_uid]))
 	    view[i] = ' ';
 	i++;
     }

src/lib/update/bp.c

@@ -71,7 +71,7 @@ static enum bp_item_idx bud_key[I_MAX + 1] = {
 static struct bp *
 bp_ref(struct bp *bp, struct sctstr *sp)
 {
-    return &bp[XYOFFSET(sp->sct_x, sp->sct_y)];
+    return &bp[sp->sct_uid];
 }
 
 /*

src/lib/update/finish.c

@@ -125,7 +125,7 @@ finish_sects(int etu)
 	if (np->nat_money < 0)
 	    continue;
 	/* Get the pointer */
-	infptr = &g_distptrs[XYOFFSET(sp->sct_x, sp->sct_y)];
+	infptr = &g_distptrs[sp->sct_uid];
 	dodistribute(sp, EXPORT,
 		     infptr->path, infptr->imcost, infptr->excost);
     }
@@ -135,7 +135,7 @@ finish_sects(int etu)
     logerror("importing...");
     for (n = 0; NULL != (sp = getsectid(n)); n++) {
 	/* Get the pointer (we do it first so we can free if needed) */
-	infptr = &g_distptrs[XYOFFSET(sp->sct_x, sp->sct_y)];
+	infptr = &g_distptrs[sp->sct_uid];
 	if (sp->sct_type == SCT_WATER || sp->sct_own == 0) {
 #ifdef SAVE_FINISH_PATHS
 	    if (infptr->path)
@@ -179,7 +179,7 @@ assemble_dist_paths(struct distinfo *distptrs)
 	if ((sp->sct_dist_x == sp->sct_x) && (sp->sct_dist_y == sp->sct_y))
 	    continue;
 	/* Set the pointer */
-	infptr = &distptrs[XYOFFSET(sp->sct_x, sp->sct_y)];
+	infptr = &distptrs[sp->sct_uid];
 	/* now, get the dist sector */
 	dist = getsectp(sp->sct_dist_x, sp->sct_dist_y);
 	if (dist == NULL) {