/* Copyright (c) 2002,2003,2005 CrystalClear Software, Inc.

 * Use, modification and distribution is subject to the 

 * Boost Software License, Version 1.0. (See accompanying

 * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)

 * Author: Jeff Garland, Bart Garst

 */

#ifndef DATE_TIME_DATE_DST_TRANSITION_DAY_GEN_HPP__

#define DATE_TIME_DATE_DST_TRANSITION_DAY_GEN_HPP__

namespace boost {

namespace date_time {

    //! Defines base interface for calculating start and end date of daylight savings 

    template<class date_type>

    class dst_day_calc_rule 

    {

    public:

      typedef typename date_type::year_type year_type;

      virtual ~dst_day_calc_rule() {};

      virtual date_type start_day(year_type y) const=0;

      virtual std::string start_rule_as_string() const=0;

      virtual date_type end_day(year_type y) const=0;

      virtual std::string end_rule_as_string() const=0;

    };

    //! Canonical form for a class that provides day rule calculation

    /*! This class is used to generate specific sets of dst rules

     *  

     *@param spec Provides a specifiction of the function object types used

     *            to generate start and end days of daylight savings as well

     *            as the date type.

     */

    template<class spec>

    class day_calc_dst_rule : public dst_day_calc_rule<typename spec::date_type>

    {

    public:

      typedef typename spec::date_type date_type;

      typedef typename date_type::year_type year_type;

      typedef typename spec::start_rule start_rule;

      typedef typename spec::end_rule  end_rule;

      day_calc_dst_rule(start_rule dst_start,

                        end_rule dst_end) :

        dst_start_(dst_start),

        dst_end_(dst_end)

      {}

      virtual date_type start_day(year_type y) const

      {

        return dst_start_.get_date(y);

      }

      virtual std::string start_rule_as_string() const

      {

        return dst_start_.to_string();

      }

      virtual date_type end_day(year_type y) const

      {

        return dst_end_.get_date(y);

      }

      virtual std::string end_rule_as_string() const

      {

        return dst_end_.to_string();

      }

    private:

      start_rule dst_start_;

      end_rule dst_end_;

    };

} }//namespace

#endif