class time_zone {
public:
  // types
  typedef boost::posix_time::time_duration time_duration_type;
  typedef time_zone_base                   base_type;         
  typedef base_type::string_type           string_type;       
  typedef base_type::stringstream_type     stringstream_type; 

  // construct/copy/destruct
  time_zone(const time_zone_names &, const time_duration_type &, 
            const dst_adjustment_offsets &, 
            boost::shared_ptr< dst_calc_rule >);
  ~time_zone();

  // public member functions
  virtual std::string dst_zone_abbrev() const;
  virtual std::string std_zone_abbrev() const;
  virtual std::string dst_zone_name() const;
  virtual std::string std_zone_name() const;
  virtual bool has_dst() const;
  virtual posix_time::ptime dst_local_start_time(gregorian::greg_year) const;
  virtual posix_time::ptime dst_local_end_time(gregorian::greg_year) const;
  virtual time_duration_type base_utc_offset() const;
  virtual time_duration_type dst_offset() const;
  virtual string_type to_posix_string() const;
};