#ifndef _GREGORIAN__CONVERSION_HPP___

#define _GREGORIAN__CONVERSION_HPP___

/* Copyright (c) 2004-2005 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

 * $Date$

 */

#include <cstring>

#include <string>

#include <stdexcept>

#include <boost/throw_exception.hpp>

#include <boost/date_time/c_time.hpp>

#include <boost/date_time/special_defs.hpp>

#include <boost/date_time/gregorian/gregorian_types.hpp>

namespace boost {

namespace gregorian {

  //! Converts a date to a tm struct. Throws out_of_range exception if date is a special value

  inline

  std::tm to_tm(const date& d)

  {

    if (d.is_special())

    {

        std::string s = "tm unable to handle ";

        switch (d.as_special())

        {

        case date_time::not_a_date_time:

            s += "not-a-date-time value"; break;

        case date_time::neg_infin:

            s += "-infinity date value"; break;

        case date_time::pos_infin:

            s += "+infinity date value"; break;

        default:

            s += "a special date value"; break;

        }

        boost::throw_exception(std::out_of_range(s));

    }

    std::tm datetm;

    std::memset(&datetm, 0, sizeof(datetm));

    boost::gregorian::date::ymd_type ymd = d.year_month_day();

    datetm.tm_year = ymd.year - 1900;

    datetm.tm_mon = ymd.month - 1;

    datetm.tm_mday = ymd.day;

    datetm.tm_wday = d.day_of_week();

    datetm.tm_yday = d.day_of_year() - 1;

    datetm.tm_isdst = -1; // negative because not enough info to set tm_isdst

    return datetm;

  }

  //! Converts a tm structure into a date dropping the any time values.

  inline

  date date_from_tm(const std::tm& datetm)

  {

    return date(static_cast<unsigned short>(datetm.tm_year+1900),

                static_cast<unsigned short>(datetm.tm_mon+1),

                static_cast<unsigned short>(datetm.tm_mday));

  }

} } //namespace boost::gregorian

#endif