#ifndef DATE_TIME_HIGHRES_TIME_CLOCK_HPP___ | |
#define DATE_TIME_HIGHRES_TIME_CLOCK_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: 2010-05-10 05:15:48 -0400 (Mon, 10 May 2010) $ | |
*/ | |
/*! @file microsec_time_clock.hpp | |
This file contains a high resolution time clock implementation. | |
*/ | |
#include <boost/cstdint.hpp> | |
#include <boost/shared_ptr.hpp> | |
#include <boost/detail/workaround.hpp> | |
#include <boost/date_time/compiler_config.hpp> | |
#include <boost/date_time/c_time.hpp> | |
#include <boost/date_time/time_clock.hpp> | |
#include <boost/date_time/filetime_functions.hpp> | |
#ifdef BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK | |
namespace boost { | |
namespace date_time { | |
//! A clock providing microsecond level resolution | |
/*! A high precision clock that measures the local time | |
* at a resolution up to microseconds and adjusts to the | |
* resolution of the time system. For example, for the | |
* a library configuration with nano second resolution, | |
* the last 3 places of the fractional seconds will always | |
* be 000 since there are 1000 nano-seconds in a micro second. | |
*/ | |
template<class time_type> | |
class microsec_clock | |
{ | |
private: | |
//! Type for the function used to convert time_t to tm | |
typedef std::tm* (*time_converter)(const std::time_t*, std::tm*); | |
public: | |
typedef typename time_type::date_type date_type; | |
typedef typename time_type::time_duration_type time_duration_type; | |
typedef typename time_duration_type::rep_type resolution_traits_type; | |
//! return a local time object for the given zone, based on computer clock | |
//JKG -- looks like we could rewrite this against universal_time | |
template<class time_zone_type> | |
static time_type local_time(shared_ptr<time_zone_type> tz_ptr) | |
{ | |
typedef typename time_type::utc_time_type utc_time_type; | |
typedef second_clock<utc_time_type> second_clock; | |
// we'll need to know the utc_offset this machine has | |
// in order to get a utc_time_type set to utc | |
utc_time_type utc_time = second_clock::universal_time(); | |
time_duration_type utc_offset = second_clock::local_time() - utc_time; | |
// use micro clock to get a local time with sub seconds | |
// and adjust it to get a true utc time reading with sub seconds | |
utc_time = microsec_clock<utc_time_type>::local_time() - utc_offset; | |
return time_type(utc_time, tz_ptr); | |
} | |
//! Returns the local time based on computer clock settings | |
static time_type local_time() | |
{ | |
return create_time(&c_time::localtime); | |
} | |
//! Returns the UTC time based on computer settings | |
static time_type universal_time() | |
{ | |
return create_time(&c_time::gmtime); | |
} | |
private: | |
static time_type create_time(time_converter converter) | |
{ | |
#ifdef BOOST_HAS_GETTIMEOFDAY | |
timeval tv; | |
gettimeofday(&tv, 0); //gettimeofday does not support TZ adjust on Linux. | |
std::time_t t = tv.tv_sec; | |
boost::uint32_t sub_sec = tv.tv_usec; | |
#elif defined(BOOST_HAS_FTIME) | |
winapi::file_time ft; | |
winapi::get_system_time_as_file_time(ft); | |
uint64_t micros = winapi::file_time_to_microseconds(ft); // it will not wrap, since ft is the current time | |
// and cannot be before 1970-Jan-01 | |
std::time_t t = static_cast<std::time_t>(micros / 1000000UL); // seconds since epoch | |
// microseconds -- static casts supress warnings | |
boost::uint32_t sub_sec = static_cast<boost::uint32_t>(micros % 1000000UL); | |
#else | |
#error Internal Boost.DateTime error: BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK is defined, however neither gettimeofday nor FILETIME support is detected. | |
#endif | |
std::tm curr; | |
std::tm* curr_ptr = converter(&t, &curr); | |
date_type d(static_cast< typename date_type::year_type::value_type >(curr_ptr->tm_year + 1900), | |
static_cast< typename date_type::month_type::value_type >(curr_ptr->tm_mon + 1), | |
static_cast< typename date_type::day_type::value_type >(curr_ptr->tm_mday)); | |
//The following line will adjust the fractional second tick in terms | |
//of the current time system. For example, if the time system | |
//doesn't support fractional seconds then res_adjust returns 0 | |
//and all the fractional seconds return 0. | |
int adjust = static_cast< int >(resolution_traits_type::res_adjust() / 1000000); | |
time_duration_type td(static_cast< typename time_duration_type::hour_type >(curr_ptr->tm_hour), | |
static_cast< typename time_duration_type::min_type >(curr_ptr->tm_min), | |
static_cast< typename time_duration_type::sec_type >(curr_ptr->tm_sec), | |
sub_sec * adjust); | |
return time_type(d,td); | |
} | |
}; | |
} } //namespace date_time | |
#endif //BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK | |
#endif | |