Re: [Boost-bugs] [Boost C++ Libraries] #3109: time_duration::total_seconds() - overflow

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #3109: time_duration::total_seconds() - overflow
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-02-08 13:28:55

#3109: time_duration::total_seconds() - overflow
-------------------------------+--------------------------------------------
  Reporter:  ioni@…            |       Owner:  az_sw_dude       
      Type:  Bugs              |      Status:  new              
 Milestone:  To Be Determined  |   Component:  date_time        
   Version:  Boost 1.41.0      |    Severity:  Problem          
Resolution:                    |    Keywords:  year 2038 problem
-------------------------------+--------------------------------------------

Comment (by Klemens Schindler):

 This problem still applies to Boost version 1.47 (I didn't check even
 newer versions)

 The following code:
 {{{#!c++
     using namespace boost::posix_time;
     using namespace boost::gregorian;
     using namespace boost::local_time;

     local_date_time now(local_sec_clock::local_time(time_zone_ptr()));
     local_date_time baseADTime( date(1601, 1, 1), hours(0),
 time_zone_ptr(), local_date_time::NOT_DATE_TIME_ON_ERROR);
     time_duration timeInterval(now.utc_time() - baseADTime.utc_time());

     cout << "BaseTime: " << baseADTime << endl;
     cout << "Time: " << now << endl;
     cout << "MicroSeconds: " << timeInterval.total_microseconds() << endl;
     cout << "MilliSeconds: " << timeInterval.total_milliseconds() << endl;
     cout << "Seconds: " << timeInterval.total_seconds() << endl;

 }}}

 produces the following output:
 {{{#!sh
 BaseTime: 1601-Jan-01 00:00:00 UTC
 Time: 2012-Feb-08 12:36:54 UTC
 MicroSeconds: 12973178214000000
 MilliSeconds: 12973178214000
 Seconds: 88276326
 }}}
 In case you're wondering why it would be interesting to calculate the time
 interval between 01-01-1601 and now: the time representation in Microsoft
 Active Directory uses a time representation based on the time between 1601
 and now.

 It is at least counterintuitive that types with a higher
 resolution/precision are able to store larger intervals. According to the
 documentation
 [[http://www.boost.org/doc/libs/1_47_0/doc/html/date_time/posix_time.html

 | documentation]], all "total_x" methods should return the same type, that
 doesn't seem to be the case.

 It is probably possible to use type traits to set the internal
 representation, but this is somewhat complex to do. (Thanks to Andrei
 Korostelev for pointing out this possibility). In any case as far as I
 know it cannot be done in an obvious/self-explanatory way.

 Another proposed solution would be to add a template parameter to
 total_seconds and similar methods so you can explicitly specify the
 representation type. For example:
 {{{#!cpp
 int_fast64_t numSeconds = timeInterval.total_seconds<int_fast64_t>()
 }}}

 This way a user explicitly states what he wants and will not run into
 surprises.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3109#comment:2>
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