ceiling and surface relocations and adjustments

relocate surface(), ceiling(), and avoid_ceiling() to dungeon.c
adjacent to has_ceiling() etc.

astral and fire, like airlevel and waterlevel return FALSE
for has_ceiling()

if a caller does happen to call ceiling() on fire level,
return "flames above"

if a caller does happen to call ceiling() on quest level,
return a more-generic "expanse above", instead of the
word "ceiling"

add "stairs" return to surface()

remove recent update to engrave.c to special-case "stairs"
since surface() will return that now

src/dungeon.c

@@ -1719,8 +1719,95 @@ Can_rise_up(coordxy x, coordxy y, d_level *lev)
 boolean
 has_ceiling(d_level *lev)
 {
-    /* [what about level 1 of the quest?] */
-    return (boolean) (!Is_airlevel(lev) && !Is_waterlevel(lev));
+    if (!(Is_astralevel(lev) || Is_firelevel(lev)
+         || Is_airlevel(lev) || Is_waterlevel(lev)))
+        return TRUE;
+    return FALSE;
+}
+
+boolean
+avoid_ceiling(d_level *lev)
+{
+    /* The quest is challenging since parts of the level
+       may have ceilings and other parts may not; Avoid
+       the ambiguity there by testing with avoid_ceiling()
+       and using alternative messaging that avoids the term
+       ceiling altogether there */
+    if (In_quest(lev) || !has_ceiling(lev))
+        return TRUE;
+    return FALSE;
+}
+
+const char *
+ceiling(coordxy x, coordxy y)
+{
+    struct rm *lev = &levl[x][y];
+    const char *what;
+
+    /* other room types will no longer exist when we're interested --
+     * see check_special_room()
+     */
+    if (*in_rooms(x, y, VAULT))
+        what = "vault's ceiling";
+    else if (*in_rooms(x, y, TEMPLE))
+        what = "temple's ceiling";
+    else if (*in_rooms(x, y, SHOPBASE))
+        what = "shop's ceiling";
+    else if (Is_waterlevel(&u.uz))
+        /* water plane has no surface; its air bubbles aren't below sky */
+        what = "water above";
+    else if (IS_AIR(lev->typ))
+        what = "sky";
+    else if (Is_firelevel(&u.uz))
+        what = "flames above";
+    else if (In_quest(&u.uz))
+        /* just in case; try to avoid in caller if you can */
+        what = "expanse above";
+    else if (Underwater)
+        what = "water's surface";
+    else if ((IS_ROOM(lev->typ) && !Is_earthlevel(&u.uz))
+             || IS_WALL(lev->typ) || IS_DOOR(lev->typ) || lev->typ == SDOOR)
+        what = "ceiling";
+    else
+        what = "rock cavern";
+
+    return what;
+}
+
+const char *
+surface(coordxy x, coordxy y)
+{
+    struct rm *lev = &levl[x][y];
+
+    if (u_at(x, y) && u.uswallow && is_animal(u.ustuck->data))
+        /* 'husk' is iffy but maw is wrong for 't' class */
+        return digests(u.ustuck->data) ? "maw"
+               : enfolds(u.ustuck->data) ? "husk"
+                 : "nonesuch"; /* can't happen (fingers crossed...) */
+    else if (IS_AIR(lev->typ) && Is_airlevel(&u.uz))
+        return "air";
+    else if (is_pool(x, y))
+        return (Underwater && !Is_waterlevel(&u.uz))
+            ? "bottom" : hliquid("water");
+    else if (is_ice(x, y))
+        return "ice";
+    else if (is_lava(x, y))
+        return hliquid("lava");
+    else if (lev->typ == DRAWBRIDGE_DOWN)
+        return "bridge";
+    else if (IS_ALTAR(levl[x][y].typ))
+        return "altar";
+    else if (IS_GRAVE(levl[x][y].typ))
+        return "headstone";
+    else if (IS_FOUNTAIN(levl[x][y].typ))
+        return "fountain";
+    else if (On_stairs(x, y))
+        return "stairs";
+    else if ((IS_ROOM(lev->typ) && !Is_earthlevel(&u.uz))
+             || IS_WALL(lev->typ) || IS_DOOR(lev->typ) || lev->typ == SDOOR)
+        return "floor";
+    else
+        return "ground";
 }
 
 /*