问题描述

boost::date_time 和 std::chrono 的互操作性如何?

How interoperable are boost::date_time and std::chrono?

例如，有没有办法在 boost::posix_time::ptime 和 std::chrono::time_point 之间转换?

For example, is there a way to convert between boost::posix_time::ptime and std::chrono::time_point?

我尝试搜索有关此类转换的文档，但找不到任何文档.

I tried searching for documentation on such conversions but couldn't find any.

推荐答案

我在 boost 提交邮件列表中找到了这个:http://lists.boost.org/boost-commit/2009/04/15209.php

I found this on the boost commits mailing list: http://lists.boost.org/boost-commit/2009/04/15209.php

以下是相关函数:

template < class Clock, class Duration> 
struct convert_to<posix_time::ptime, chrono::time_point<Clock, Duration> > { 
    inline static posix_time::ptime apply(const chrono::time_point<Clock, Duration>& from) 
    { 
        typedef chrono::time_point<Clock, Duration> time_point_t; 
        typedef chrono::nanoseconds duration_t; 
        typedef duration_t::rep rep_t; 
        rep_t d = chrono::duration_cast<duration_t>(from.time_since_epoch()).count(); 
        rep_t sec = d/1000000000; 
        rep_t nsec = d%1000000000; 
        return boost::posix_time::from_time_t(0)+ 
        boost::posix_time::seconds(static_cast<long>(sec))+ 
        #ifdef BOOST_DATE_TIME_HAS_NANOSECONDS 
        boost::posix_time::nanoseconds(nsec); 
        #else 
        boost::posix_time::microseconds((nsec+500)/1000); 
        #endif 
    } 
}; 

template < class Clock, class Duration> 
struct convert_to<chrono::time_point<Clock, Duration>, posix_time::ptime> { 
    inline static chrono::time_point<Clock, Duration> apply(const posix_time::ptime& from) 
    { 
        boost::posix_time::time_duration const time_since_epoch=from-boost::posix_time::from_time_t(0); 
        chrono::time_point<Clock, Duration> t=chrono::system_clock::from_time_t(time_since_epoch.total_seconds()); 
        long nsec=time_since_epoch.fractional_seconds()*(1000000000/time_since_epoch.ticks_per_second()); 
        return t+chrono::nanoseconds(nsec); 

    } 
}; 

我不确定它们何时会成为 Boost 版本的一部分.他们现在似乎不在升压后备箱中...

I'm not sure when they're going to become part of a boost release. They don't seem to be in boost trunk right now...

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