boost/date_time/local_time/local_date_time.hpp
#ifndef LOCAL_TIME_LOCAL_DATE_TIME_HPP__ #define LOCAL_TIME_LOCAL_DATE_TIME_HPP__ /* Copyright (c) 2003-2005 CrystalClear Software, Inc. * 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: 2010-01-10 14:17:23 -0500 (Sun, 10 Jan 2010) $ */ #include <string> #include <iomanip> #include <sstream> #include <stdexcept> #include <boost/shared_ptr.hpp> #include <boost/throw_exception.hpp> #include <boost/date_time/time.hpp> #include <boost/date_time/posix_time/posix_time.hpp> //todo remove? #include <boost/date_time/dst_rules.hpp> #include <boost/date_time/time_zone_base.hpp> #include <boost/date_time/special_defs.hpp> #include <boost/date_time/time_resolution_traits.hpp> // absolute_value namespace boost { namespace local_time { //! simple exception for reporting when STD or DST cannot be determined struct ambiguous_result : public std::logic_error { ambiguous_result (std::string const& msg = std::string()) : std::logic_error(std::string("Daylight Savings Results are ambiguous: " + msg)) {} }; //! simple exception for when time label given cannot exist struct time_label_invalid : public std::logic_error { time_label_invalid (std::string const& msg = std::string()) : std::logic_error(std::string("Time label given is invalid: " + msg)) {} }; struct dst_not_valid: public std::logic_error { dst_not_valid(std::string const& msg = std::string()) : std::logic_error(std::string("is_dst flag does not match resulting dst for time label given: " + msg)) {} }; //TODO: I think these should be in local_date_time_base and not // necessarily brought into the namespace using date_time::time_is_dst_result; using date_time::is_in_dst; using date_time::is_not_in_dst; using date_time::ambiguous; using date_time::invalid_time_label; //! Representation of "wall-clock" time in a particular time zone /*! Representation of "wall-clock" time in a particular time zone * Local_date_time_base holds a time value (date and time offset from 00:00) * along with a time zone. The time value is stored as UTC and conversions * to wall clock time are made as needed. This approach allows for * operations between wall-clock times in different time zones, and * daylight savings time considerations, to be made. Time zones are * required to be in the form of a boost::shared_ptr<time_zone_base>. */ template<class utc_time_=posix_time::ptime, class tz_type=date_time::time_zone_base<utc_time_,char> > class local_date_time_base : public date_time::base_time<utc_time_, boost::posix_time::posix_time_system> { public: typedef utc_time_ utc_time_type; typedef typename utc_time_type::time_duration_type time_duration_type; typedef typename utc_time_type::date_type date_type; typedef typename date_type::duration_type date_duration_type; typedef typename utc_time_type::time_system_type time_system_type; /*! This constructor interprets the passed time as a UTC time. * So, for example, if the passed timezone is UTC-5 then the * time will be adjusted back 5 hours. The time zone allows for * automatic calculation of whether the particular time is adjusted for * daylight savings, etc. * If the time zone shared pointer is null then time stays unadjusted. *@param t A UTC time *@param tz Timezone for to adjust the UTC time to. */ local_date_time_base(utc_time_type t, boost::shared_ptr<tz_type> tz) : date_time::base_time<utc_time_type, time_system_type>(t), zone_(tz) { // param was already utc so nothing more to do } /*! This constructs a local time -- the passed time information * understood to be in the passed tz. The DST flag must be passed * to indicate whether the time is in daylight savings or not. * @throws -- time_label_invalid if the time passed does not exist in * the given locale. The non-existent case occurs typically * during the shift-back from daylight savings time. When * the clock is shifted forward a range of times * (2 am to 3 am in the US) is skipped and hence is invalid. * @throws -- dst_not_valid if the DST flag is passed for a period * where DST is not active. */ local_date_time_base(date_type d, time_duration_type td, boost::shared_ptr<tz_type> tz, bool dst_flag) : //necessary for constr_adj() date_time::base_time<utc_time_type,time_system_type>(construction_adjustment(utc_time_type(d, td), tz, dst_flag)), zone_(tz) { if(tz != boost::shared_ptr<tz_type>() && tz->has_dst()){ // d & td are already local so we use them time_is_dst_result result = check_dst(d, td, tz); bool in_dst = (result == is_in_dst); // less processing than is_dst() // ambig occurs at end, invalid at start if(result == invalid_time_label){ // Ex: 2:15am local on trans-in day in nyc, dst_flag irrelevant std::ostringstream ss; ss << "time given: " << d << ' ' << td; boost::throw_exception(time_label_invalid(ss.str())); } else if(result != ambiguous && in_dst != dst_flag){ // is dst_flag accurate? // Ex: false flag in NYC in June std::ostringstream ss; ss.setf(std::ios_base::boolalpha); ss << "flag given: dst=" << dst_flag << ", dst calculated: dst=" << in_dst; boost::throw_exception(dst_not_valid(ss.str())); } // everything checks out and conversion to utc already done } } //TODO maybe not the right set...Ignore the last 2 for now... enum DST_CALC_OPTIONS { EXCEPTION_ON_ERROR, NOT_DATE_TIME_ON_ERROR }; //ASSUME_DST_ON_ERROR, ASSUME_NOT_DST_ON_ERROR }; /*! This constructs a local time -- the passed time information * understood to be in the passed tz. The DST flag is calculated * according to the specified rule. */ local_date_time_base(date_type d, time_duration_type td, boost::shared_ptr<tz_type> tz, DST_CALC_OPTIONS calc_option) : // dummy value - time_ is set in constructor code date_time::base_time<utc_time_type,time_system_type>(utc_time_type(d,td)), zone_(tz) { time_is_dst_result result = check_dst(d, td, tz); if(result == ambiguous) { if(calc_option == EXCEPTION_ON_ERROR){ std::ostringstream ss; ss << "time given: " << d << ' ' << td; boost::throw_exception(ambiguous_result(ss.str())); } else{ // NADT on error this->time_ = posix_time::posix_time_system::get_time_rep(date_type(date_time::not_a_date_time), time_duration_type(date_time::not_a_date_time)); } } else if(result == invalid_time_label){ if(calc_option == EXCEPTION_ON_ERROR){ std::ostringstream ss; ss << "time given: " << d << ' ' << td; boost::throw_exception(time_label_invalid(ss.str())); } else{ // NADT on error this->time_ = posix_time::posix_time_system::get_time_rep(date_type(date_time::not_a_date_time), time_duration_type(date_time::not_a_date_time)); } } else if(result == is_in_dst){ utc_time_type t = construction_adjustment(utc_time_type(d, td), tz, true); this->time_ = posix_time::posix_time_system::get_time_rep(t.date(), t.time_of_day()); } else{ utc_time_type t = construction_adjustment(utc_time_type(d, td), tz, false); this->time_ = posix_time::posix_time_system::get_time_rep(t.date(), t.time_of_day()); } } //! Determines if given time label is in daylight savings for given zone /*! Determines if given time label is in daylight savings for given zone. * Takes a date and time_duration representing a local time, along * with time zone, and returns a time_is_dst_result object as result. */ static time_is_dst_result check_dst(date_type d, time_duration_type td, boost::shared_ptr<tz_type> tz) { if(tz != boost::shared_ptr<tz_type>() && tz->has_dst()) { typedef typename date_time::dst_calculator<date_type, time_duration_type> dst_calculator; return dst_calculator::local_is_dst( d, td, tz->dst_local_start_time(d.year()).date(), tz->dst_local_start_time(d.year()).time_of_day(), tz->dst_local_end_time(d.year()).date(), tz->dst_local_end_time(d.year()).time_of_day(), tz->dst_offset() ); } else{ return is_not_in_dst; } } //! Simple destructor, releases time zone if last referrer ~local_date_time_base() {}; //! Copy constructor local_date_time_base(const local_date_time_base& rhs) : date_time::base_time<utc_time_type, time_system_type>(rhs), zone_(rhs.zone_) {} //! Special values constructor explicit local_date_time_base(const boost::date_time::special_values sv, boost::shared_ptr<tz_type> tz = boost::shared_ptr<tz_type>()) : date_time::base_time<utc_time_type, time_system_type>(utc_time_type(sv)), zone_(tz) {} //! returns time zone associated with calling instance boost::shared_ptr<tz_type> zone() const { return zone_; } //! returns false is time_zone is NULL and if time value is a special_value bool is_dst() const { if(zone_ != boost::shared_ptr<tz_type>() && zone_->has_dst() && !this->is_special()) { // check_dst takes a local time, *this is utc utc_time_type lt(this->time_); lt += zone_->base_utc_offset(); // dst_offset only needs to be considered with ambiguous time labels // make that adjustment there switch(check_dst(lt.date(), lt.time_of_day(), zone_)){ case is_not_in_dst: return false; case is_in_dst: return true; case ambiguous: if(lt + zone_->dst_offset() < zone_->dst_local_end_time(lt.date().year())) { return true; } break; case invalid_time_label: if(lt >= zone_->dst_local_start_time(lt.date().year())) { return true; } break; } } return false; } //! Returns object's time value as a utc representation utc_time_type utc_time() const { return utc_time_type(this->time_); } //! Returns object's time value as a local representation utc_time_type local_time() const { if(zone_ != boost::shared_ptr<tz_type>()){ utc_time_type lt = this->utc_time() + zone_->base_utc_offset(); if (is_dst()) { lt += zone_->dst_offset(); } return lt; } return utc_time_type(this->time_); } //! Returns string in the form "2003-Aug-20 05:00:00 EDT" /*! Returns string in the form "2003-Aug-20 05:00:00 EDT". If * time_zone is NULL the time zone abbreviation will be "UTC". The time * zone abbrev will not be included if calling object is a special_value*/ std::string to_string() const { //TODO is this a temporary function ??? std::ostringstream ss; if(this->is_special()){ ss << utc_time(); return ss.str(); } if(zone_ == boost::shared_ptr<tz_type>()) { ss << utc_time() << " UTC"; return ss.str(); } bool is_dst_ = is_dst(); utc_time_type lt = this->utc_time() + zone_->base_utc_offset(); if (is_dst_) { lt += zone_->dst_offset(); } ss << local_time() << " "; if (is_dst()) { ss << zone_->dst_zone_abbrev(); } else { ss << zone_->std_zone_abbrev(); } return ss.str(); } /*! returns a local_date_time_base in the given time zone with the * optional time_duration added. */ local_date_time_base local_time_in(boost::shared_ptr<tz_type> new_tz, time_duration_type td=time_duration_type(0,0,0)) const { return local_date_time_base(utc_time_type(this->time_) + td, new_tz); } //! Returns name of associated time zone or "Coordinated Universal Time". /*! Optional bool parameter will return time zone as an offset * (ie "+07:00" extended iso format). Empty string is returned for * classes that do not use a time_zone */ std::string zone_name(bool as_offset=false) const { if(zone_ == boost::shared_ptr<tz_type>()) { if(as_offset) { return std::string("Z"); } else { return std::string("Coordinated Universal Time"); } } if (is_dst()) { if(as_offset) { time_duration_type td = zone_->base_utc_offset(); td += zone_->dst_offset(); return zone_as_offset(td, ":"); } else { return zone_->dst_zone_name(); } } else { if(as_offset) { time_duration_type td = zone_->base_utc_offset(); return zone_as_offset(td, ":"); } else { return zone_->std_zone_name(); } } } //! Returns abbreviation of associated time zone or "UTC". /*! Optional bool parameter will return time zone as an offset * (ie "+0700" iso format). Empty string is returned for classes * that do not use a time_zone */ std::string zone_abbrev(bool as_offset=false) const { if(zone_ == boost::shared_ptr<tz_type>()) { if(as_offset) { return std::string("Z"); } else { return std::string("UTC"); } } if (is_dst()) { if(as_offset) { time_duration_type td = zone_->base_utc_offset(); td += zone_->dst_offset(); return zone_as_offset(td, ""); } else { return zone_->dst_zone_abbrev(); } } else { if(as_offset) { time_duration_type td = zone_->base_utc_offset(); return zone_as_offset(td, ""); } else { return zone_->std_zone_abbrev(); } } } //! returns a posix_time_zone string for the associated time_zone. If no time_zone, "UTC+00" is returned. std::string zone_as_posix_string() const { if(zone_ == shared_ptr<tz_type>()) { return std::string("UTC+00"); } return zone_->to_posix_string(); } //! Equality comparison operator /*bool operator==(const date_time::base_time<boost::posix_time::ptime,boost::posix_time::posix_time_system>& rhs) const { // fails due to rhs.time_ being protected return date_time::base_time<boost::posix_time::ptime,boost::posix_time::posix_time_system>::operator==(rhs); //return this->time_ == rhs.time_; }*/ //! Equality comparison operator bool operator==(const local_date_time_base& rhs) const { return time_system_type::is_equal(this->time_, rhs.time_); } //! Non-Equality comparison operator bool operator!=(const local_date_time_base& rhs) const { return !(*this == rhs); } //! Less than comparison operator bool operator<(const local_date_time_base& rhs) const { return time_system_type::is_less(this->time_, rhs.time_); } //! Less than or equal to comparison operator bool operator<=(const local_date_time_base& rhs) const { return (*this < rhs || *this == rhs); } //! Greater than comparison operator bool operator>(const local_date_time_base& rhs) const { return !(*this <= rhs); } //! Greater than or equal to comparison operator bool operator>=(const local_date_time_base& rhs) const { return (*this > rhs || *this == rhs); } //! Local_date_time + date_duration local_date_time_base operator+(const date_duration_type& dd) const { return local_date_time_base(time_system_type::add_days(this->time_,dd), zone_); } //! Local_date_time += date_duration local_date_time_base operator+=(const date_duration_type& dd) { this->time_ = time_system_type::add_days(this->time_,dd); return *this; } //! Local_date_time - date_duration local_date_time_base operator-(const date_duration_type& dd) const { return local_date_time_base(time_system_type::subtract_days(this->time_,dd), zone_); } //! Local_date_time -= date_duration local_date_time_base operator-=(const date_duration_type& dd) { this->time_ = time_system_type::subtract_days(this->time_,dd); return *this; } //! Local_date_time + time_duration local_date_time_base operator+(const time_duration_type& td) const { return local_date_time_base(time_system_type::add_time_duration(this->time_,td), zone_); } //! Local_date_time += time_duration local_date_time_base operator+=(const time_duration_type& td) { this->time_ = time_system_type::add_time_duration(this->time_,td); return *this; } //! Local_date_time - time_duration local_date_time_base operator-(const time_duration_type& td) const { return local_date_time_base(time_system_type::subtract_time_duration(this->time_,td), zone_); } //! Local_date_time -= time_duration local_date_time_base operator-=(const time_duration_type& td) { this->time_ = time_system_type::subtract_time_duration(this->time_,td); return *this; } //! local_date_time -= local_date_time --> time_duration_type time_duration_type operator-(const local_date_time_base& rhs) const { return utc_time_type(this->time_) - utc_time_type(rhs.time_); } private: boost::shared_ptr<tz_type> zone_; //bool is_dst_; /*! Adjust the passed in time to UTC? */ utc_time_type construction_adjustment(utc_time_type t, boost::shared_ptr<tz_type> z, bool dst_flag) { if(z != boost::shared_ptr<tz_type>()) { if(dst_flag && z->has_dst()) { t -= z->dst_offset(); } // else no adjust t -= z->base_utc_offset(); } return t; } /*! Simple formatting code -- todo remove this? */ std::string zone_as_offset(const time_duration_type& td, const std::string& separator) const { std::ostringstream ss; if(td.is_negative()) { // a negative duration is represented as "-[h]h:mm" // we require two digits for the hour. A positive duration // with the %H flag will always give two digits ss << "-"; } else { ss << "+"; } ss << std::setw(2) << std::setfill('0') << date_time::absolute_value(td.hours()) << separator << std::setw(2) << std::setfill('0') << date_time::absolute_value(td.minutes()); return ss.str(); } }; //!Use the default parameters to define local_date_time typedef local_date_time_base<> local_date_time; } } #endif