Re: [Boost-users] [date_time]time zone input

From: Jeff Garland (jeff_at_[hidden])
Date: 2006-10-01 22:31:31

Sean Huang wrote:
> ----- Original Message ----- 
> From: "Jeff Garland" <jeff_at_[hidden]>
> To: <boost-users_at_[hidden]>
> Sent: Sunday, October 01, 2006 8:03 PM
> Subject: Re: [Boost-users] [date_time]time zone input
> 
> 
>>> That would be great. What we are trying to do is to convert DICOM DT 
>>> (Date
>>> time) element to boost::date_time and it is in the format shown below:
>>> YYYYMMDDHHMMSS.FFFFFF&ZZZZ
>>> One way I can think of is treat the string as posix time and parse the
>>> time-zone offset part ourselves. It sounds like there are better ways to
>>> accomplish this. I would appreciate it very much if you could point me to
>>> the right direction.
>> That's exactly what I would suggest, although actually you can probably 
>> parse
>> it into a time_duration.
> Can you elaborate on this a bit more?

See below.

> I just use it to do a one-time adjustment. I agree with you that the 
> aforemented format does not fully specify a time zone (I guess I used the 
> wrong subject in the first place. :-)). DICOM only uses the ZZZZ as the 
> offset from UTC and that's how we plan to use ZZZZ. We'll convert it to UTC 
> time as soon as it is parsed.

Ok, easy as pie.  We'll set the time_duration_format format, stream it in and 
convert to utc:

     try {
       //setup your input facet
       time_input_facet *facet = new time_input_facet();
       facet->set_iso_format();
       facet->time_duration_format("%H%M"); // just get a tz parts
       some_stream_instance.imbue(std::locale(std::locale::classic(), facet));

       //stream the parts in
       ptime t;
       time_duration td(0,0,0);

       //get the time part
       t >> some_stream_instance;
       //now get the utc offset
       td >> some_stream_instance;
       t += td; //convert time to UTC
     }
     catch(std::exception& e)

I didn't compile or run this...you'll what some error handling...but I'm 99% 
sure it will do what you want :-)

Jeff