/**
   * Process the unchecked tiles that are still needed to be done.
   *
   * @return <code>true</code> in case a tile was handled.
   */
  private boolean processUnchecked() {
    long key;
    synchronized (unchecked) {
      final int size = unchecked.size();
      if (size == 0) {
        return false;
      }
      key = unchecked.removeAt(size - 1);
    }

    final MapTile tile = parent.getMapAt(key);

    // no tile found, lets quit here
    if (tile == null) {
      return true;
    }

    // clipping check
    if (checkClipping(tile, key)) {
      return true;
    }

    // obstruction check
    if (checkObstruction(tile, key)) {
      return true;
    }

    // hidden check
    if (checkHidden(tile, key)) {
      return true;
    }

    return true;
  }
 private void readRouteTreeData(
     RouteSubregion routeTree,
     TLongArrayList idTables,
     TLongObjectHashMap<TLongArrayList> restrictions)
     throws IOException {
   routeTree.dataObjects = new ArrayList<RouteDataObject>();
   idTables.clear();
   restrictions.clear();
   List<String> stringTable = null;
   while (true) {
     int t = codedIS.readTag();
     int tag = WireFormat.getTagFieldNumber(t);
     switch (tag) {
       case 0:
         TLongObjectIterator<TLongArrayList> it = restrictions.iterator();
         while (it.hasNext()) {
           it.advance();
           int from = (int) it.key();
           RouteDataObject fromr = routeTree.dataObjects.get(from);
           fromr.restrictions = new long[it.value().size()];
           for (int k = 0; k < fromr.restrictions.length; k++) {
             int to = (int) (it.value().get(k) >> RouteDataObject.RESTRICTION_SHIFT);
             long valto =
                 (idTables.get(to) << RouteDataObject.RESTRICTION_SHIFT)
                     | ((long) it.value().get(k) & RouteDataObject.RESTRICTION_MASK);
             fromr.restrictions[k] = valto;
           }
         }
         for (RouteDataObject o : routeTree.dataObjects) {
           if (o != null) {
             if (o.id < idTables.size()) {
               o.id = idTables.get((int) o.id);
             }
             if (o.names != null && stringTable != null) {
               int[] keys = o.names.keys();
               for (int j = 0; j < keys.length; j++) {
                 o.names.put(keys[j], stringTable.get(o.names.get(keys[j]).charAt(0)));
               }
             }
           }
         }
         return;
       case RouteDataBlock.DATAOBJECTS_FIELD_NUMBER:
         int length = codedIS.readRawVarint32();
         int oldLimit = codedIS.pushLimit(length);
         RouteDataObject obj =
             readRouteDataObject(routeTree.routeReg, routeTree.left, routeTree.top);
         while (obj.id >= routeTree.dataObjects.size()) {
           routeTree.dataObjects.add(null);
         }
         routeTree.dataObjects.set((int) obj.id, obj);
         codedIS.popLimit(oldLimit);
         break;
       case RouteDataBlock.IDTABLE_FIELD_NUMBER:
         long routeId = 0;
         length = codedIS.readRawVarint32();
         oldLimit = codedIS.pushLimit(length);
         idLoop:
         while (true) {
           int ts = codedIS.readTag();
           int tags = WireFormat.getTagFieldNumber(ts);
           switch (tags) {
             case 0:
               break idLoop;
             case IdTable.ROUTEID_FIELD_NUMBER:
               routeId += codedIS.readSInt64();
               idTables.add(routeId);
               break;
             default:
               skipUnknownField(ts);
               break;
           }
         }
         codedIS.popLimit(oldLimit);
         break;
       case RouteDataBlock.RESTRICTIONS_FIELD_NUMBER:
         length = codedIS.readRawVarint32();
         oldLimit = codedIS.pushLimit(length);
         long from = 0;
         long to = 0;
         long type = 0;
         idLoop:
         while (true) {
           int ts = codedIS.readTag();
           int tags = WireFormat.getTagFieldNumber(ts);
           switch (tags) {
             case 0:
               break idLoop;
             case RestrictionData.FROM_FIELD_NUMBER:
               from = codedIS.readInt32();
               break;
             case RestrictionData.TO_FIELD_NUMBER:
               to = codedIS.readInt32();
               break;
             case RestrictionData.TYPE_FIELD_NUMBER:
               type = codedIS.readInt32();
               break;
             default:
               skipUnknownField(ts);
               break;
           }
         }
         if (!restrictions.containsKey(from)) {
           restrictions.put(from, new TLongArrayList());
         }
         restrictions.get(from).add((to << RouteDataObject.RESTRICTION_SHIFT) + type);
         codedIS.popLimit(oldLimit);
         break;
       case RouteDataBlock.STRINGTABLE_FIELD_NUMBER:
         length = codedIS.readRawVarint32();
         oldLimit = codedIS.pushLimit(length);
         stringTable = map.readStringTable();
         //				codedIS.skipRawBytes(codedIS.getBytesUntilLimit());
         codedIS.popLimit(oldLimit);
         break;
       default:
         skipUnknownField(t);
         break;
     }
   }
 }