#ifndef DATE_TIME_C_LOCAL_TIME_ADJUSTOR_HPP__ | |
#define DATE_TIME_C_LOCAL_TIME_ADJUSTOR_HPP__ | |
/* 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 | |
* $Date: 2008-11-12 14:37:53 -0500 (Wed, 12 Nov 2008) $ | |
*/ | |
/*! @file c_local_time_adjustor.hpp | |
Time adjustment calculations based on machine | |
*/ | |
#include <stdexcept> | |
#include <boost/throw_exception.hpp> | |
#include <boost/date_time/compiler_config.hpp> | |
#include <boost/date_time/c_time.hpp> | |
namespace boost { | |
namespace date_time { | |
//! Adjust to / from utc using the C API | |
/*! Warning!!! This class assumes that timezone settings of the | |
* machine are correct. This can be a very dangerous assumption. | |
*/ | |
template<class time_type> | |
class c_local_adjustor { | |
public: | |
typedef typename time_type::time_duration_type time_duration_type; | |
typedef typename time_type::date_type date_type; | |
typedef typename date_type::duration_type date_duration_type; | |
//! Convert a utc time to local time | |
static time_type utc_to_local(const time_type& t) | |
{ | |
date_type time_t_start_day(1970,1,1); | |
time_type time_t_start_time(time_t_start_day,time_duration_type(0,0,0)); | |
if (t < time_t_start_time) { | |
boost::throw_exception(std::out_of_range("Cannot convert dates prior to Jan 1, 1970")); | |
BOOST_DATE_TIME_UNREACHABLE_EXPRESSION(return time_t_start_time); // should never reach | |
} | |
date_duration_type dd = t.date() - time_t_start_day; | |
time_duration_type td = t.time_of_day(); | |
std::time_t t2 = dd.days()*86400 + td.hours()*3600 + td.minutes()*60 + td.seconds(); | |
std::tm tms, *tms_ptr; | |
tms_ptr = c_time::localtime(&t2, &tms); | |
date_type d(static_cast<unsigned short>(tms_ptr->tm_year + 1900), | |
static_cast<unsigned short>(tms_ptr->tm_mon + 1), | |
static_cast<unsigned short>(tms_ptr->tm_mday)); | |
time_duration_type td2(tms_ptr->tm_hour, | |
tms_ptr->tm_min, | |
tms_ptr->tm_sec, | |
t.time_of_day().fractional_seconds()); | |
return time_type(d,td2); | |
} | |
}; | |
} } //namespace date_time | |
#endif |