date_generators.hpp

来自「support vector clustering for vc++」· HPP 代码 · 共 510 行 · 第 1/2 页

    typedef typename date_type::calendar_type calendar_type;
    typedef typename calendar_type::day_of_week_type  day_of_week_type;
    typedef typename calendar_type::month_type        month_type;
    typedef typename calendar_type::year_type         year_type;
    typedef typename date_type::duration_type        duration_type;
    //!Specify the first 'Sunday' in 'April' spec
    /*!@param dow The day of week, eg: Sunday, Monday, etc
     * @param m The month of the year, eg: Jan, Feb, Mar, etc
     */
    first_kday_of_month(day_of_week_type dow, month_type m) :
      month_(m),
      dow_(dow)
    {}
    //! Return a concrete date when provided with a year specific year.
    date_type get_date(year_type year) const
    {
      date_type d(year, month_,1);
      duration_type one_day(1);
      while (dow_ != d.day_of_week()) {
        d = d + one_day;
      }
      return d;
        }
    // added for streaming
    month_type month() const
    {
      return month_;
    }
    day_of_week_type day_of_week() const
    {
      return dow_;
    }
    //! Returns string suitable for use in POSIX time zone string
    /*! Returns a string formatted as "M4.1.0" ==> 1st Sunday in April. */
    virtual std::string to_string() const
    {
     std::stringstream ss;
     ss << 'M' 
       << static_cast<int>(month_) << '.'
       << 1 << '.'
       << static_cast<int>(dow_);
     return ss.str();
    }
  private:
    month_type month_;
    day_of_week_type dow_;
  };
  
  
  
  //! Calculate something like Last Sunday of January
  /*! Useful generator functor for finding holidays and daylight savings
   *  Get the last day of the month and then calculate the difference
   *  to the last previous day.
   *  @param date_type A date class that exports day_of_week, month_type, etc.
   *  \ingroup date_alg
   */
  template<class date_type>
  class last_kday_of_month : public year_based_generator<date_type>
  {
  public:
    typedef typename date_type::calendar_type calendar_type;
    typedef typename calendar_type::day_of_week_type  day_of_week_type;
    typedef typename calendar_type::month_type        month_type;
    typedef typename calendar_type::year_type         year_type;
    typedef typename date_type::duration_type        duration_type;
    //!Specify the date spec like last 'Sunday' in 'April' spec
    /*!@param dow The day of week, eg: Sunday, Monday, etc
     * @param m The month of the year, eg: Jan, Feb, Mar, etc
     */
    last_kday_of_month(day_of_week_type dow, month_type m) :
      month_(m),
      dow_(dow)
    {}
    //! Return a concrete date when provided with a year specific year.
    date_type get_date(year_type year) const
    {
      date_type d(year, month_, calendar_type::end_of_month_day(year,month_));
      duration_type one_day(1);
      while (dow_ != d.day_of_week()) {
        d = d - one_day;
      }
      return d;
    }
    // added for streaming
    month_type month() const
    {
      return month_;
    }
    day_of_week_type day_of_week() const
    {
      return dow_;
    }
    //! Returns string suitable for use in POSIX time zone string
    /*! Returns a string formatted as "M4.5.0" ==> last Sunday in April. */
    virtual std::string to_string() const
    {
      std::stringstream ss;
      ss << 'M' 
         << static_cast<int>(month_) << '.'
         << 5 << '.'
         << static_cast<int>(dow_);
      return ss.str();
    }
  private:
    month_type month_;
    day_of_week_type dow_;
   };
  
  
  //! Calculate something like "First Sunday after Jan 1,2002
  /*! Date generator that takes a date and finds kday after
   *@code
     typedef boost::date_time::first_kday_after<date> firstkdayafter;
     firstkdayafter fkaf(Monday);
     fkaf.get_date(date(2002,Feb,1));
   @endcode
   *  \ingroup date_alg
   */
  template<class date_type>
  class first_kday_after
  {
  public:
    typedef typename date_type::calendar_type calendar_type;
    typedef typename calendar_type::day_of_week_type day_of_week_type;
    typedef typename date_type::duration_type        duration_type;
    first_kday_after(day_of_week_type dow) :
      dow_(dow)
    {}
    //! Return next kday given.
    date_type get_date(date_type start_day) const
    {
      duration_type one_day(1);
      date_type d = start_day + one_day;
      while (dow_ != d.day_of_week()) {
        d = d + one_day;
      }
      return d;
    }
    // added for streaming
    day_of_week_type day_of_week() const
    {
      return dow_;
    }
  private:
    day_of_week_type dow_;
  };
  
  //! Calculate something like "First Sunday before Jan 1,2002
  /*! Date generator that takes a date and finds kday after
   *@code
     typedef boost::date_time::first_kday_before<date> firstkdaybefore;
     firstkdaybefore fkbf(Monday);
     fkbf.get_date(date(2002,Feb,1));
   @endcode
   *  \ingroup date_alg
   */
  template<class date_type>
  class first_kday_before
  {
  public:
    typedef typename date_type::calendar_type calendar_type;
    typedef typename calendar_type::day_of_week_type day_of_week_type;
    typedef typename date_type::duration_type        duration_type;
    first_kday_before(day_of_week_type dow) :
      dow_(dow)
    {}
    //! Return next kday given.
    date_type get_date(date_type start_day) const
    {
      duration_type one_day(1);
      date_type d = start_day - one_day;
      while (dow_ != d.day_of_week()) {
        d = d - one_day;
      }
      return d;
    }
    // added for streaming
    day_of_week_type day_of_week() const
    {
      return dow_;
    }
  private:
    day_of_week_type dow_;
  };
  
  //! Calculates the number of days until the next weekday
  /*! Calculates the number of days until the next weekday.
   * If the date given falls on a Sunday and the given weekday 
   * is Tuesday the result will be 2 days */
  template<typename date_type, class weekday_type>
  inline
  typename date_type::duration_type days_until_weekday(const date_type& d, const weekday_type& wd)
  {
    typedef typename date_type::duration_type duration_type;
    duration_type wks(0);
    duration_type dd(wd.as_number() - d.day_of_week().as_number());
    if(dd.is_negative()){
      wks = duration_type(7);
    }
    return dd + wks;
  }

  //! Calculates the number of days since the previous weekday
  /*! Calculates the number of days since the previous weekday
   * If the date given falls on a Sunday and the given weekday 
   * is Tuesday the result will be 5 days. The answer will be a positive 
   * number because Tuesday is 5 days before Sunday, not -5 days before. */
  template<typename date_type, class weekday_type>
  inline
  typename date_type::duration_type days_before_weekday(const date_type& d, const weekday_type& wd)
  {
    typedef typename date_type::duration_type duration_type;
    duration_type wks(0);
    duration_type dd(wd.as_number() - d.day_of_week().as_number());
    if(dd.days() > 0){
      wks = duration_type(7);
    }
    // we want a number of days, not an offset. The value returned must
    // be zero or larger.
    return (-dd + wks);
  }

  //! Generates a date object representing the date of the following weekday from the given date
  /*! Generates a date object representing the date of the following 
   * weekday from the given date. If the date given is 2004-May-9 
   * (a Sunday) and the given weekday is Tuesday then the resulting date 
   * will be 2004-May-11. */
  template<class date_type, class weekday_type>
  inline
  date_type next_weekday(const date_type& d, const weekday_type& wd)
  {
    return d + days_until_weekday(d, wd);
  }

  //! Generates a date object representing the date of the previous weekday from the given date
  /*! Generates a date object representing the date of the previous 
   * weekday from the given date. If the date given is 2004-May-9 
   * (a Sunday) and the given weekday is Tuesday then the resulting date 
   * will be 2004-May-4. */
  template<class date_type, class weekday_type>
  inline
  date_type previous_weekday(const date_type& d, const weekday_type& wd)
  {
    return d - days_before_weekday(d, wd);
  }

} } //namespace date_time




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