stack.push(reverse(encoded.subSequence(start, idx)));

    if (c == '!' || c == '?' || c == ':' || c == ',') {
      // '!' represents an interior node that represents a REGISTRY entry in the map.
      // '?' represents a leaf node, which represents a REGISTRY entry in map.
      // ':' represents an interior node that represents a private entry in the map
      // ',' represents a leaf node, which represents a private entry in the map.