#ifndef LOCAL_TIME_DATE_DURATION_OPERATORS_HPP___

#define LOCAL_TIME_DATE_DURATION_OPERATORS_HPP___

/* Copyright (c) 2004 CrystalClear Software, Inc.

 * 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: 2008-02-27 15:00:24 -0500 (Wed, 27 Feb 2008) $

 */

#include "boost/date_time/gregorian/greg_duration_types.hpp"

#include "boost/date_time/local_time/local_date_time.hpp"

namespace boost {

namespace local_time {

  /*!@file date_duration_operators.hpp Operators for local_date_time and 

   * optional gregorian types. Operators use snap-to-end-of-month behavior. 

   * Further details on this behavior can be found in reference for 

   * date_time/date_duration_types.hpp and documentation for 

   * month and year iterators.

   */

  /*! Adds a months object and a local_date_time. Result will be same 

   * day-of-month as local_date_time unless original day was the last day of month.

   * see date_time::months_duration for more details */

  inline

  local_date_time 

  operator+(const local_date_time& t, const boost::gregorian::months& m)

  {

    return t + m.get_offset(t.utc_time().date());

  }

  /*! Adds a months object to a local_date_time. Result will be same 

   * day-of-month as local_date_time unless original day was the last day of month.

   * see date_time::months_duration for more details */

  inline

  local_date_time 

  operator+=(local_date_time& t, const boost::gregorian::months& m)

  {

    return t += m.get_offset(t.utc_time().date());

  }

  /*! Subtracts a months object and a local_date_time. Result will be same 

   * day-of-month as local_date_time unless original day was the last day of month.

   * see date_time::months_duration for more details */

  inline

  local_date_time 

  operator-(const local_date_time& t, const boost::gregorian::months& m)

  {

    // get_neg_offset returns a negative duration, so we add

    return t + m.get_neg_offset(t.utc_time().date());

  }

  /*! Subtracts a months object from a local_date_time. Result will be same 

   * day-of-month as local_date_time unless original day was the last day of month.

   * see date_time::months_duration for more details */

  inline

  local_date_time 

  operator-=(local_date_time& t, const boost::gregorian::months& m)

  {

    // get_neg_offset returns a negative duration, so we add

    return t += m.get_neg_offset(t.utc_time().date());

  }

  // local_date_time & years

  /*! Adds a years object and a local_date_time. Result will be same 

   * month and day-of-month as local_date_time unless original day was the 

   * last day of month. see date_time::years_duration for more details */

  inline

  local_date_time 

  operator+(const local_date_time& t, const boost::gregorian::years& y)

  {

    return t + y.get_offset(t.utc_time().date());

  }

  /*! Adds a years object to a local_date_time. Result will be same 

   * month and day-of-month as local_date_time unless original day was the 

   * last day of month. see date_time::years_duration for more details */

  inline

  local_date_time 

  operator+=(local_date_time& t, const boost::gregorian::years& y)

  {

    return t += y.get_offset(t.utc_time().date());

  }

  /*! Subtracts a years object and a local_date_time. Result will be same 

   * month and day-of-month as local_date_time unless original day was the 

   * last day of month. see date_time::years_duration for more details */

  inline

  local_date_time 

  operator-(const local_date_time& t, const boost::gregorian::years& y)

  {

    // get_neg_offset returns a negative duration, so we add

    return t + y.get_neg_offset(t.utc_time().date());

  }

  /*! Subtracts a years object from a local_date_time. Result will be same 

   * month and day-of-month as local_date_time unless original day was the 

   * last day of month. see date_time::years_duration for more details */

  inline

  local_date_time 

  operator-=(local_date_time& t, const boost::gregorian::years& y)

  {

    // get_neg_offset returns a negative duration, so we add

    return t += y.get_neg_offset(t.utc_time().date());

  }

}} // namespaces

#endif // LOCAL_TIME_DATE_DURATION_OPERATORS_HPP___