[datetime] IANA Time Zone Database
Hi Boost, I have files with timestamps in various timezones. I would like to be able to convert these timestamps, no matter what timezone they are in (I know the names of the timezones) to UTC timestamps. I looked through datatime library documentation and found date_time_zonespec.csv database which doesn't seem to support the notion of different rules for the same timezone depending on the date. For example, Russia used to have summer time but not any more. Another method seems to be passing a timezone specification string manually, which requires the user to figure what it should be for a particular date. In other words, given a timestamp and its timezone, I would like to be able to convert that timestamp into a UTC timestamp using conversion rules in force at that particular date in the past. Ideally, this would use IANA Time Zone Database or something similar. Is there a facility in boost to do just that? -- Maxim
On Thu, Nov 8, 2012 at 7:53 AM, Maxim Yegorushkin < maxim.yegorushkin@gmail.com> wrote:
Hi Boost,
I have files with timestamps in various timezones. I would like to be able to convert these timestamps, no matter what timezone they are in (I know the names of the timezones) to UTC timestamps.
I looked through datatime library documentation and found date_time_zonespec.csv database which doesn't seem to support the notion of different rules for the same timezone depending on the date. For example, Russia used to have summer time but not any more. Another method seems to be passing a timezone specification string manually, which requires the user to figure what it should be for a particular date.
In other words, given a timestamp and its timezone, I would like to be able to convert that timestamp into a UTC timestamp using conversion rules in force at that particular date in the past. Ideally, this would use IANA Time Zone Database or something similar. Is there a facility in boost to do just that?
Hi Maxim - That would require an extension to date-time to handle -- all the interfaces are there, but the machinery to lookup in a database that has historical entries would need to be developed. Unfortunately it's not a function that's been requested much and there isn't really a plan to develop it...sorry. Jeff
You can use Boost.Locale that is compiled with ICU backend. ICU supports Time Zone database and you can specify the timezone by its name, parse time or create date_time object and get POSIX (UTC) time form it. Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.com/ CppDB - C++ SQL Connectivity: http://cppcms.com/sql/cppdb/
________________________________ From: Maxim Yegorushkin <maxim.yegorushkin@gmail.com> To: boost@lists.boost.org Sent: Thursday, November 8, 2012 4:53 PM Subject: [boost] [datetime] IANA Time Zone Database
Hi Boost,
I have files with timestamps in various timezones. I would like to be able to convert these timestamps, no matter what timezone they are in (I know the names of the timezones) to UTC timestamps.
I looked through datatime library documentation and found date_time_zonespec.csv database which doesn't seem to support the notion of different rules for the same timezone depending on the date. For example, Russia used to have summer time but not any more. Another method seems to be passing a timezone specification string manually, which requires the user to figure what it should be for a particular date.
In other words, given a timestamp and its timezone, I would like to be able to convert that timestamp into a UTC timestamp using conversion rules in force at that particular date in the past. Ideally, this would use IANA Time Zone Database or something similar. Is there a facility in boost to do just that?
-- Maxim
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On 08/11/12 15:15, Artyom Beilis wrote:
You can use Boost.Locale that is compiled with ICU backend.
ICU supports Time Zone database and you can specify the timezone by its name, parse time or create
date_time object and get POSIX (UTC) time form it.
Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.com/ CppDB - C++ SQL Connectivity: http://cppcms.com/sql/cppdb/
________________________________ From: Maxim Yegorushkin <maxim.yegorushkin@gmail.com> To: boost@lists.boost.org Sent: Thursday, November 8, 2012 4:53 PM Subject: [boost] [datetime] IANA Time Zone Database
Hi Boost,
I have files with timestamps in various timezones. I would like to be able to convert these timestamps, no matter what timezone they are in (I know the names of the timezones) to UTC timestamps.
I looked through datatime library documentation and found date_time_zonespec.csv database which doesn't seem to support the notion of different rules for the same timezone depending on the date. For example, Russia used to have summer time but not any more. Another method seems to be passing a timezone specification string manually, which requires the user to figure what it should be for a particular date.
In other words, given a timestamp and its timezone, I would like to be able to convert that timestamp into a UTC timestamp using conversion rules in force at that particular date in the past. Ideally, this would use IANA Time Zone Database or something similar. Is there a facility in boost to do just that?
Oh, thanks Artyom. That is quite a surprising place to find this functionality. Not sure why it is not in datetime library. Anyway, I managed to get a small test working: #include <iostream> #include <sstream> #include <boost/locale.hpp> int main() { boost::locale::generator gen; std::locale::global(gen("en_GB.UTF-8")); std::cout.imbue(std::locale()); boost::locale::date_time d; std::istringstream ss("8 Nov 2012 17:00:00"); ss >> boost::locale::as::time_zone("America/New_York") >> d; std::cout << boost::locale::as::time_zone("UTC") << d << '\n'; // prints 8 Nov 2012 22:00:00 } Thanks a lot! -- Maxim
On Thu, Nov 8, 2012 at 10:36 AM, Maxim Yegorushkin < maxim.yegorushkin@gmail.com> wrote:
Oh, thanks Artyom.
That is quite a surprising place to find this functionality. Not sure why it is not in datetime library.
Anyway, I managed to get a small test working:
#include <iostream> #include <sstream> #include <boost/locale.hpp>
int main() { boost::locale::generator gen; std::locale::global(gen("en_**GB.UTF-8")); std::cout.imbue(std::locale())**;
boost::locale::date_time d; std::istringstream ss("8 Nov 2012 17:00:00"); ss >> boost::locale::as::time_zone("**America/New_York") >> d;
std::cout << boost::locale::as::time_zone("**UTC") << d << '\n'; // prints 8 Nov 2012 22:00:00 }
Thanks a lot!
-- Maxim
Yes, surprising -- obviously I've been asleep b/c I was completely unaware of this work...seems like we now have a lot of library duplication :-(
On Fri, Nov 9, 2012 at 4:54 AM, Jeff Garland <azswdude@gmail.com> wrote:
On Thu, Nov 8, 2012 at 10:36 AM, Maxim Yegorushkin < maxim.yegorushkin@gmail.com> wrote:
Oh, thanks Artyom.
That is quite a surprising place to find this functionality. Not sure why it is not in datetime library.
Anyway, I managed to get a small test working:
#include <iostream> #include <sstream> #include <boost/locale.hpp>
int main() { boost::locale::generator gen; std::locale::global(gen("en_**GB.UTF-8")); std::cout.imbue(std::locale())**;
boost::locale::date_time d; std::istringstream ss("8 Nov 2012 17:00:00"); ss >> boost::locale::as::time_zone("**America/New_York") >> d;
std::cout << boost::locale::as::time_zone("**UTC") << d << '\n'; // prints 8 Nov 2012 22:00:00 }
Thanks a lot!
-- Maxim
Yes, surprising -- obviously I've been asleep b/c I was completely unaware of this work...seems like we now have a lot of library duplication :-(
_______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
The Boost.Locale docs explain why it it has its own date and time functionality rather than using or building on for example Boost.DateTime: http://www.boost.org/doc/libs/1_52_0/libs/locale/doc/html/dates_times_timezo...
On Thu, Nov 8, 2012 at 8:24 PM, Joshua Boyce <raptorfactor@raptorfactor.com>wrote:
The Boost.Locale docs explain why it it has its own date and time functionality rather than using or building on for example Boost.DateTime:
http://www.boost.org/doc/libs/1_52_0/libs/locale/doc/html/dates_times_timezo...
Thanks that's helpful. Unfortunately, I don't think some of the analysis on this page is correct. Good that I see this now, though so that I can work with Artyom and make sure this stuff is in date_time2 :-) Jeff
----- Original Message -----
From: Jeff Garland <azswdude@gmail.com> To: boost@lists.boost.org Cc: Sent: Friday, November 9, 2012 12:52 PM Subject: Re: [boost] [datetime] IANA Time Zone Database
On Thu, Nov 8, 2012 at 8:24 PM, Joshua Boyce <raptorfactor@raptorfactor.com>wrote:
The Boost.Locale docs explain why it it has its own date and time functionality rather than using or building on for example Boost.DateTime:
http://www.boost.org/doc/libs/1_52_0/libs/locale/doc/html/dates_times_timezo...
Thanks that's helpful. Unfortunately, I don't think some of the analysis on this page is correct. Good that I see this now, though so that I can work with Artyom and make sure this stuff is in date_time2 :-)
I mostly had 3 major problems with boost.DateTime: 1. Broken TZ API (you see the discussion, it is not capable of handling all TZ in Olson DB) 2. There is a mixup of POSIX time (ptime) and local time for example stuff like ptime second_clock::local_time() Makes no sense (for me) as POSIX time is by _definition_ UTC time. 3. There was a need of locale aware date handling, which is ok. I think boost date_time can be significantly improved, and I assume boost::locale::date_time as well. I'd be glad to cooperate.
Jeff
Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.com/ CppDB - C++ SQL Connectivity: http://cppcms.com/sql/cppdb/
On 08/11/12 17:36, Maxim Yegorushkin wrote:
On 08/11/12 15:15, Artyom Beilis wrote:
You can use Boost.Locale that is compiled with ICU backend.
ICU supports Time Zone database and you can specify the timezone by its name, parse time or create
date_time object and get POSIX (UTC) time form it.
Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.com/ CppDB - C++ SQL Connectivity: http://cppcms.com/sql/cppdb/
________________________________ From: Maxim Yegorushkin <maxim.yegorushkin@gmail.com> To: boost@lists.boost.org Sent: Thursday, November 8, 2012 4:53 PM Subject: [boost] [datetime] IANA Time Zone Database
Hi Boost,
I have files with timestamps in various timezones. I would like to be able to convert these timestamps, no matter what timezone they are in (I know the names of the timezones) to UTC timestamps.
I looked through datatime library documentation and found date_time_zonespec.csv database which doesn't seem to support the notion of different rules for the same timezone depending on the date. For example, Russia used to have summer time but not any more. Another method seems to be passing a timezone specification string manually, which requires the user to figure what it should be for a particular date.
In other words, given a timestamp and its timezone, I would like to be able to convert that timestamp into a UTC timestamp using conversion rules in force at that particular date in the past. Ideally, this would use IANA Time Zone Database or something similar. Is there a facility in boost to do just that?
Oh, thanks Artyom.
That is quite a surprising place to find this functionality. Not sure why it is not in datetime library.
Anyway, I managed to get a small test working:
#include <iostream> #include <sstream> #include <boost/locale.hpp>
int main() { boost::locale::generator gen; std::locale::global(gen("en_GB.UTF-8")); std::cout.imbue(std::locale());
boost::locale::date_time d; std::istringstream ss("8 Nov 2012 17:00:00"); ss >> boost::locale::as::time_zone("America/New_York") >> d;
std::cout << boost::locale::as::time_zone("UTC") << d << '\n'; // prints 8 Nov 2012 22:00:00 }
Thanks a lot!
Thinking more about it, my local times are coming in as broken down time representation (year, month, ...), so I won't be dealing with streams at all. Is there a way to do timezone conversions without using streams? Something similar to pytz: timezone paris("Europe/Paris"), utc("UTC"); date_time t(2012, 10, 9, 10, 19, 0); // no timezone associated date_time utc_t(paris.localize(t).astimezone(utc)); ? -- Maxim
On Fri, Nov 9, 2012 at 3:22 AM, Maxim Yegorushkin < maxim.yegorushkin@gmail.com> wrote:
Thinking more about it, my local times are coming in as broken down time representation (year, month, ...), so I won't be dealing with streams at all.
Is there a way to do timezone conversions without using streams? Something similar to pytz:
timezone paris("Europe/Paris"), utc("UTC"); date_time t(2012, 10, 9, 10, 19, 0); // no timezone associated date_time utc_t(paris.localize(t).**astimezone(utc));
?
You're probably asking about locale, but this you can do in date_time: ptime pt(date(2004,Nov,5), hours(10)); time_zone_ptr zone(new posix_time_zone("MST-07")); local_date_time az(pt, zone); cout << az.utc_time() << endl; // 10am 2004-Nov-5 cout << az.local_time() << endl; // 3am 2004-Nov-5 time_zone_ptr nyc_zone = ... //get an nyc timezone local_date_time nyc = az.local_time_in(nyc_zone); In bdt the time_zone is abstract -- so you can build your own time zone names and such in any fashion you like. What's needed to handle all the historic cases correctly is a derivative of time_zone which has the history and when asked to convert local to utc, adjusts appropriately for the relative time historically (effectively a list of offset rules). There's an example and code that creates custom timezone types. And lastly, you'd need to create some code to parse the iana data and create the tz objects to lookup by string...not a huge amount of work. Certainly this should be out of the box some day...
On 2012-11-09 12:29, Jeff Garland wrote:
In bdt the time_zone is abstract -- so you can build your own time zone names and such in any fashion you like. What's needed to handle all the historic cases correctly is a derivative of time_zone which has the history and when asked to convert local to utc, adjusts appropriately for the relative time historically (effectively a list of offset rules).
Unfortunately, time_zone_base is not able to handle "any fashion you like", e.g., the Olsen database. It assumes exactly 2 switches per year, whereas there are cases that require 1 or 3 time zone changes in a single year. Cheers, Rutger
On Fri, Nov 9, 2012 at 4:56 AM, Rutger ter Borg <rutger@terborg.net> wrote:
Unfortunately, time_zone_base is not able to handle "any fashion you like", e.g., the Olsen database. It assumes exactly 2 switches per year, whereas there are cases that require 1 or 3 time zone changes in a single year.
Well maybe, although some of this might be treated a bit differently. I guess I'll have to look those examples up, but a "1 time per year" sounds more like a permanent shift in base time from UTC then dst change. And not sure what you'd do with 3 either. If that's the case, v2 will have to treat these events as a list. Jeff
----- Original Message -----
From: Maxim Yegorushkin <maxim.yegorushkin@gmail.com> To: boost@lists.boost.org Cc: Sent: Friday, November 9, 2012 12:22 PM Subject: Re: [boost] [datetime] IANA Time Zone Database
On 08/11/12 15:15, Artyom Beilis wrote:
You can use Boost.Locale that is compiled with ICU backend.
ICU supports Time Zone database and you can specify the timezone by its name, parse time or create
date_time object and get POSIX (UTC) time form it.
Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.com/ CppDB - C++ SQL Connectivity: http://cppcms.com/sql/cppdb/
________________________________ From: Maxim Yegorushkin <maxim.yegorushkin@gmail.com> To: boost@lists.boost.org Sent: Thursday, November 8, 2012 4:53 PM Subject: [boost] [datetime] IANA Time Zone Database
Hi Boost,
I have files with timestamps in various timezones. I would like to be able to convert these timestamps, no matter what timezone they are in (I know the names of the timezones) to UTC timestamps.
I looked through datatime library documentation and found date_time_zonespec.csv database which doesn't seem to support
On 08/11/12 17:36, Maxim Yegorushkin wrote: the
notion of different rules for the same timezone depending on the date. For example, Russia used to have summer time but not any more. Another method seems to be passing a timezone specification string manually, which requires the user to figure what it should be for a particular date.
In other words, given a timestamp and its timezone, I would like to be able to convert that timestamp into a UTC timestamp using conversion rules in force at that particular date in the past. Ideally, this would use IANA Time Zone Database or something similar. Is there a facility in boost to do just that?
Oh, thanks Artyom.
That is quite a surprising place to find this functionality. Not sure why it is not in datetime library.
Anyway, I managed to get a small test working: [snip]
Thanks a lot!
Thinking more about it, my local times are coming in as broken down time representation (year, month, ...), so I won't be dealing with streams at all.
Is there a way to do timezone conversions without using streams? Something similar to pytz:
timezone paris("Europe/Paris"), utc("UTC"); date_time t(2012, 10, 9, 10, 19, 0); // no timezone associated date_time utc_t(paris.localize(t).astimezone(utc));
?
-- Maxim
First you can create boost::locale::calendar using TZ name http://www.boost.org/doc/libs/1_52_0/libs/locale/doc/html/classboost_1_1loca... Than you create a date_time object using calendar and than setup all parameters you need. http://www.boost.org/doc/libs/1_52_0/libs/locale/doc/html/classboost_1_1loca... It should be something like using namespace boost::locale::period; boost::locale::date_time dt( year(2012) + month(10) + day(9) + hour(10) + minute(19) + second(0), boost::locale::calendar("Europe/Paris")); Than you can get a POSIX time from it dt.time(), print it to stream with UTC time zone or create other date_time object like boost::locale::date_time dt_utc(dt.time(),boost::locale::calendar("UTC")); And fetch its parameters. I hadn't tested the chunk of code above but this is a general direction. Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.com/ CppDB - C++ SQL Connectivity: http://cppcms.com/sql/cppdb/
On 09/11/12 14:38, Artyom Beilis wrote: []
First you can create boost::locale::calendar using TZ name
http://www.boost.org/doc/libs/1_52_0/libs/locale/doc/html/classboost_1_1loca...
Than you create a date_time object using calendar and than setup all parameters you need.
http://www.boost.org/doc/libs/1_52_0/libs/locale/doc/html/classboost_1_1loca...
It should be something like using namespace boost::locale::period; boost::locale::date_time dt( year(2012) + month(10) + day(9) + hour(10) + minute(19) + second(0), boost::locale::calendar("Europe/Paris"));
Than you can get a POSIX time from it dt.time(), print it to stream with UTC time zone or create other date_time object like
boost::locale::date_time dt_utc(dt.time(),boost::locale::calendar("UTC"));
And fetch its parameters.
I hadn't tested the chunk of code above but this is a general direction.
Thanks again Artyom, this is exactly what I was looking for. -- Maxim
Hi! Artyom Beilis wrote:
You can use Boost.Locale that is compiled with ICU backend.
ICU supports Time Zone database and you can specify the timezone by its name, parse time or create
date_time object and get POSIX (UTC) time form it.
On POSIX systems with tzdata installed Boost.Locale could also have this feature without ICU. Any plans to do this? best regards Markus Raab -- http://www.markus-raab.org | "Those who make peaceful revolution -o) | impossible, will make violent revolution Kernel 2.6.32-5-a /\ | inevitable." -- John F. Kennedy on a x86_64 _\_v |
On 09/11/12 05:57, Markus Raab wrote:
Artyom Beilis wrote:
You can use Boost.Locale that is compiled with ICU backend.
ICU supports Time Zone database and you can specify the timezone by its name, parse time or create
date_time object and get POSIX (UTC) time form it.
On POSIX systems with tzdata installed Boost.Locale could also have this feature without ICU. Any plans to do this?
Not sure if it could, since there is no official API in C standard library to do timezone conversions between arbitrary timezones and UTC. Only between the local timezone and UTC. http://sourceware.org/bugzilla/show_bug.cgi?id=11620 -- Maxim
________________________________ From: Markus Raab <usenet@markus-raab.org> To: boost@lists.boost.org Sent: Friday, November 9, 2012 7:57 AM Subject: Re: [boost] [datetime] IANA Time Zone Database
Hi!
Artyom Beilis wrote:
You can use Boost.Locale that is compiled with ICU backend.
ICU supports Time Zone database and you can specify the timezone by its name, parse time or create
date_time object and get POSIX (UTC) time form it.
On POSIX systems with tzdata installed Boost.Locale could also have this feature without ICU. Any plans to do this?
Currently there is no API that allows to to get TZ offset for specific date for specific time zone. The OS API that provides TZ handing is limited and assumes global TZ. The only way I can see, and it is probably simpler way is to use Olson database directly and implement it withing Boost.Locale.
best regards Markus Raab
on a x86_64 _\_v |
Regards, Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.com/ CppDB - C++ SQL Connectivity: http://cppcms.com/sql/cppdb/
participants (6)
-
Artyom Beilis -
Jeff Garland -
Joshua Boyce -
Markus Raab -
Maxim Yegorushkin -
Rutger ter Borg