1#ifndef LOCAL_TIME_LOCAL_DATE_TIME_HPP__
2#define LOCAL_TIME_LOCAL_DATE_TIME_HPP__
3
4/* Copyright (c) 2003-2005 CrystalClear Software, Inc.
5 * Subject to the Boost Software License, Version 1.0.
6 * (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
7 * Author: Jeff Garland, Bart Garst
8 * $Date$
9 */
10
11#include <string>
12#include <iomanip>
13#include <sstream>
14#include <stdexcept>
15#include <boost/shared_ptr.hpp>
16#include <boost/throw_exception.hpp>
17#include <boost/date_time/time.hpp>
18#include <boost/date_time/posix_time/posix_time.hpp> //todo remove?
19#include <boost/date_time/compiler_config.hpp>
20#include <boost/date_time/dst_rules.hpp>
21#include <boost/date_time/time_zone_base.hpp>
22#include <boost/date_time/special_defs.hpp>
23#include <boost/date_time/time_resolution_traits.hpp> // absolute_value
24
25namespace boost {
26namespace local_time {
27
28 //! simple exception for reporting when STD or DST cannot be determined
29 struct BOOST_SYMBOL_VISIBLE ambiguous_result : public std::logic_error
30 {
31 ambiguous_result (std::string const& msg = std::string()) :
32 std::logic_error(std::string("Daylight Savings Results are ambiguous: " + msg)) {}
33 };
34 //! simple exception for when time label given cannot exist
35 struct BOOST_SYMBOL_VISIBLE time_label_invalid : public std::logic_error
36 {
37 time_label_invalid (std::string const& msg = std::string()) :
38 std::logic_error(std::string("Time label given is invalid: " + msg)) {}
39 };
40 struct BOOST_SYMBOL_VISIBLE dst_not_valid: public std::logic_error
41 {
42 dst_not_valid(std::string const& msg = std::string()) :
43 std::logic_error(std::string("is_dst flag does not match resulting dst for time label given: " + msg)) {}
44 };
45
46 //TODO: I think these should be in local_date_time_base and not
47 // necessarily brought into the namespace
48 using date_time::time_is_dst_result;
49 using date_time::is_in_dst;
50 using date_time::is_not_in_dst;
51 using date_time::ambiguous;
52 using date_time::invalid_time_label;
53
54 //! Representation of "wall-clock" time in a particular time zone
55 /*! Representation of "wall-clock" time in a particular time zone
56 * Local_date_time_base holds a time value (date and time offset from 00:00)
57 * along with a time zone. The time value is stored as UTC and conversions
58 * to wall clock time are made as needed. This approach allows for
59 * operations between wall-clock times in different time zones, and
60 * daylight savings time considerations, to be made. Time zones are
61 * required to be in the form of a boost::shared_ptr<time_zone_base>.
62 */
63 template<class utc_time_=posix_time::ptime,
64 class tz_type=date_time::time_zone_base<utc_time_,char> >
65 class BOOST_SYMBOL_VISIBLE local_date_time_base : public date_time::base_time<utc_time_,
66 boost::posix_time::posix_time_system> {
67 public:
68 typedef utc_time_ utc_time_type;
69 typedef typename utc_time_type::time_duration_type time_duration_type;
70 typedef typename utc_time_type::date_type date_type;
71 typedef typename date_type::duration_type date_duration_type;
72 typedef typename utc_time_type::time_system_type time_system_type;
73 /*! This constructor interprets the passed time as a UTC time.
74 * So, for example, if the passed timezone is UTC-5 then the
75 * time will be adjusted back 5 hours. The time zone allows for
76 * automatic calculation of whether the particular time is adjusted for
77 * daylight savings, etc.
78 * If the time zone shared pointer is null then time stays unadjusted.
79 *@param t A UTC time
80 *@param tz Timezone for to adjust the UTC time to.
81 */
82 local_date_time_base(utc_time_type t,
83 boost::shared_ptr<tz_type> tz) :
84 date_time::base_time<utc_time_type, time_system_type>(t),
85 zone_(tz)
86 {
87 // param was already utc so nothing more to do
88 }
89
90 /*! This constructs a local time -- the passed time information
91 * understood to be in the passed tz. The DST flag must be passed
92 * to indicate whether the time is in daylight savings or not.
93 * @throws -- time_label_invalid if the time passed does not exist in
94 * the given locale. The non-existent case occurs typically
95 * during the shift-back from daylight savings time. When
96 * the clock is shifted forward a range of times
97 * (2 am to 3 am in the US) is skipped and hence is invalid.
98 * @throws -- dst_not_valid if the DST flag is passed for a period
99 * where DST is not active.
100 */
101 local_date_time_base(date_type d,
102 time_duration_type td,
103 boost::shared_ptr<tz_type> tz,
104 bool dst_flag) : //necessary for constr_adj()
105 date_time::base_time<utc_time_type,time_system_type>(construction_adjustment(t: utc_time_type(d, td), z: tz, dst_flag)),
106 zone_(tz)
107 {
108 if(tz != boost::shared_ptr<tz_type>() && tz->has_dst()){
109
110 // d & td are already local so we use them
111 time_is_dst_result result = check_dst(d, td, tz);
112 bool in_dst = (result == is_in_dst); // less processing than is_dst()
113
114 // ambig occurs at end, invalid at start
115 if(result == invalid_time_label){
116 // Ex: 2:15am local on trans-in day in nyc, dst_flag irrelevant
117 std::ostringstream ss;
118 ss << "time given: " << d << ' ' << td;
119 boost::throw_exception(e: time_label_invalid(ss.str()));
120 }
121 else if(result != ambiguous && in_dst != dst_flag){
122 // is dst_flag accurate?
123 // Ex: false flag in NYC in June
124 std::ostringstream ss;
125 ss.setf(std::ios_base::boolalpha);
126 ss << "flag given: dst=" << dst_flag << ", dst calculated: dst=" << in_dst;
127 boost::throw_exception(e: dst_not_valid(ss.str()));
128 }
129
130 // everything checks out and conversion to utc already done
131 }
132 }
133
134 //TODO maybe not the right set...Ignore the last 2 for now...
135 enum DST_CALC_OPTIONS { EXCEPTION_ON_ERROR, NOT_DATE_TIME_ON_ERROR };
136 //ASSUME_DST_ON_ERROR, ASSUME_NOT_DST_ON_ERROR };
137
138 /*! This constructs a local time -- the passed time information
139 * understood to be in the passed tz. The DST flag is calculated
140 * according to the specified rule.
141 */
142 local_date_time_base(date_type d,
143 time_duration_type td,
144 boost::shared_ptr<tz_type> tz,
145 DST_CALC_OPTIONS calc_option) :
146 // dummy value - time_ is set in constructor code
147 date_time::base_time<utc_time_type,time_system_type>(utc_time_type(d,td)),
148 zone_(tz)
149 {
150 time_is_dst_result result = check_dst(d, td, tz);
151 if(result == ambiguous) {
152 if(calc_option == EXCEPTION_ON_ERROR){
153 std::ostringstream ss;
154 ss << "time given: " << d << ' ' << td;
155 boost::throw_exception(e: ambiguous_result(ss.str()));
156 }
157 else{ // NADT on error
158 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));
159 }
160 }
161 else if(result == invalid_time_label){
162 if(calc_option == EXCEPTION_ON_ERROR){
163 std::ostringstream ss;
164 ss << "time given: " << d << ' ' << td;
165 boost::throw_exception(e: time_label_invalid(ss.str()));
166 }
167 else{ // NADT on error
168 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));
169 }
170 }
171 else if(result == is_in_dst){
172 utc_time_type t =
173 construction_adjustment(t: utc_time_type(d, td), z: tz, dst_flag: true);
174 this->time_ = posix_time::posix_time_system::get_time_rep(t.date(),
175 t.time_of_day());
176 }
177 else{
178 utc_time_type t =
179 construction_adjustment(t: utc_time_type(d, td), z: tz, dst_flag: false);
180 this->time_ = posix_time::posix_time_system::get_time_rep(t.date(),
181 t.time_of_day());
182 }
183 }
184
185
186 //! Determines if given time label is in daylight savings for given zone
187 /*! Determines if given time label is in daylight savings for given zone.
188 * Takes a date and time_duration representing a local time, along
189 * with time zone, and returns a time_is_dst_result object as result.
190 */
191 static time_is_dst_result check_dst(date_type d,
192 time_duration_type td,
193 boost::shared_ptr<tz_type> tz)
194 {
195 if(tz != boost::shared_ptr<tz_type>() && tz->has_dst()) {
196 typedef typename date_time::dst_calculator<date_type, time_duration_type> dst_calculator;
197 return dst_calculator::local_is_dst(
198 d, td,
199 tz->dst_local_start_time(d.year()).date(),
200 tz->dst_local_start_time(d.year()).time_of_day(),
201 tz->dst_local_end_time(d.year()).date(),
202 tz->dst_local_end_time(d.year()).time_of_day(),
203 tz->dst_offset()
204 );
205 }
206 else{
207 return is_not_in_dst;
208 }
209 }
210
211 //! Simple destructor, releases time zone if last referrer
212 ~local_date_time_base() {}
213
214 //! Copy constructor
215 local_date_time_base(const local_date_time_base& rhs) :
216 date_time::base_time<utc_time_type, time_system_type>(rhs),
217 zone_(rhs.zone_)
218 {}
219
220 //! Special values constructor
221 explicit local_date_time_base(const boost::date_time::special_values sv,
222 boost::shared_ptr<tz_type> tz = boost::shared_ptr<tz_type>()) :
223 date_time::base_time<utc_time_type, time_system_type>(utc_time_type(sv)),
224 zone_(tz)
225 {}
226
227 //! returns time zone associated with calling instance
228 boost::shared_ptr<tz_type> zone() const
229 {
230 return zone_;
231 }
232 //! returns false is time_zone is NULL and if time value is a special_value
233 bool is_dst() const
234 {
235 if(zone_ != boost::shared_ptr<tz_type>() && zone_->has_dst() && !this->is_special()) {
236 // check_dst takes a local time, *this is utc
237 utc_time_type lt(this->time_);
238 lt += zone_->base_utc_offset();
239 // dst_offset only needs to be considered with ambiguous time labels
240 // make that adjustment there
241
242 switch(check_dst(d: lt.date(), td: lt.time_of_day(), tz: zone_)){
243 case is_not_in_dst:
244 return false;
245 case is_in_dst:
246 return true;
247 case ambiguous:
248 if(lt + zone_->dst_offset() < zone_->dst_local_end_time(lt.date().year())) {
249 return true;
250 }
251 break;
252 case invalid_time_label:
253 if(lt >= zone_->dst_local_start_time(lt.date().year())) {
254 return true;
255 }
256 break;
257 }
258 }
259 return false;
260 }
261 //! Returns object's time value as a utc representation
262 utc_time_type utc_time() const
263 {
264 return utc_time_type(this->time_);
265 }
266 //! Returns object's time value as a local representation
267 utc_time_type local_time() const
268 {
269 if(zone_ != boost::shared_ptr<tz_type>()){
270 utc_time_type lt = this->utc_time() + zone_->base_utc_offset();
271 if (is_dst()) {
272 lt += zone_->dst_offset();
273 }
274 return lt;
275 }
276 return utc_time_type(this->time_);
277 }
278 //! Returns string in the form "2003-Aug-20 05:00:00 EDT"
279 /*! Returns string in the form "2003-Aug-20 05:00:00 EDT". If
280 * time_zone is NULL the time zone abbreviation will be "UTC". The time
281 * zone abbrev will not be included if calling object is a special_value*/
282 std::string to_string() const
283 {
284 //TODO is this a temporary function ???
285 std::ostringstream ss;
286 if(this->is_special()){
287 ss << utc_time();
288 return ss.str();
289 }
290 if(zone_ == boost::shared_ptr<tz_type>()) {
291 ss << utc_time() << " UTC";
292 return ss.str();
293 }
294 bool is_dst_ = is_dst();
295 utc_time_type lt = this->utc_time() + zone_->base_utc_offset();
296 if (is_dst_) {
297 lt += zone_->dst_offset();
298 }
299 ss << local_time() << " ";
300 if (is_dst()) {
301 ss << zone_->dst_zone_abbrev();
302 }
303 else {
304 ss << zone_->std_zone_abbrev();
305 }
306 return ss.str();
307 }
308 /*! returns a local_date_time_base in the given time zone with the
309 * optional time_duration added. */
310 local_date_time_base local_time_in(boost::shared_ptr<tz_type> new_tz,
311 time_duration_type td=time_duration_type(0,0,0)) const
312 {
313 return local_date_time_base(utc_time_type(this->time_) + td, new_tz);
314 }
315
316 //! Returns name of associated time zone or "Coordinated Universal Time".
317 /*! Optional bool parameter will return time zone as an offset
318 * (ie "+07:00" extended ISO 8601 format). Empty string is returned for
319 * classes that do not use a time_zone */
320 std::string zone_name(bool as_offset=false) const
321 {
322 if(zone_ == boost::shared_ptr<tz_type>()) {
323 if(as_offset) {
324 return std::string("Z");
325 }
326 else {
327 return std::string("Coordinated Universal Time");
328 }
329 }
330 if (is_dst()) {
331 if(as_offset) {
332 time_duration_type td = zone_->base_utc_offset();
333 td += zone_->dst_offset();
334 return zone_as_offset(td, separator: ":");
335 }
336 else {
337 return zone_->dst_zone_name();
338 }
339 }
340 else {
341 if(as_offset) {
342 time_duration_type td = zone_->base_utc_offset();
343 return zone_as_offset(td, separator: ":");
344 }
345 else {
346 return zone_->std_zone_name();
347 }
348 }
349 }
350 //! Returns abbreviation of associated time zone or "UTC".
351 /*! Optional bool parameter will return time zone as an offset
352 * (ie "+0700" ISO 8601 format). Empty string is returned for classes
353 * that do not use a time_zone */
354 std::string zone_abbrev(bool as_offset=false) const
355 {
356 if(zone_ == boost::shared_ptr<tz_type>()) {
357 if(as_offset) {
358 return std::string("Z");
359 }
360 else {
361 return std::string("UTC");
362 }
363 }
364 if (is_dst()) {
365 if(as_offset) {
366 time_duration_type td = zone_->base_utc_offset();
367 td += zone_->dst_offset();
368 return zone_as_offset(td, separator: "");
369 }
370 else {
371 return zone_->dst_zone_abbrev();
372 }
373 }
374 else {
375 if(as_offset) {
376 time_duration_type td = zone_->base_utc_offset();
377 return zone_as_offset(td, separator: "");
378 }
379 else {
380 return zone_->std_zone_abbrev();
381 }
382 }
383 }
384
385 //! returns a posix_time_zone string for the associated time_zone. If no time_zone, "UTC+00" is returned.
386 std::string zone_as_posix_string() const
387 {
388 if(zone_ == shared_ptr<tz_type>()) {
389 return std::string("UTC+00");
390 }
391 return zone_->to_posix_string();
392 }
393
394 //! Equality comparison operator
395 /*bool operator==(const date_time::base_time<boost::posix_time::ptime,boost::posix_time::posix_time_system>& rhs) const
396 { // fails due to rhs.time_ being protected
397 return date_time::base_time<boost::posix_time::ptime,boost::posix_time::posix_time_system>::operator==(rhs);
398 //return this->time_ == rhs.time_;
399 }*/
400 //! Equality comparison operator
401 bool operator==(const local_date_time_base& rhs) const
402 {
403 return time_system_type::is_equal(this->time_, rhs.time_);
404 }
405 //! Non-Equality comparison operator
406 bool operator!=(const local_date_time_base& rhs) const
407 {
408 return !(*this == rhs);
409 }
410 //! Less than comparison operator
411 bool operator<(const local_date_time_base& rhs) const
412 {
413 return time_system_type::is_less(this->time_, rhs.time_);
414 }
415 //! Less than or equal to comparison operator
416 bool operator<=(const local_date_time_base& rhs) const
417 {
418 return (*this < rhs || *this == rhs);
419 }
420 //! Greater than comparison operator
421 bool operator>(const local_date_time_base& rhs) const
422 {
423 return !(*this <= rhs);
424 }
425 //! Greater than or equal to comparison operator
426 bool operator>=(const local_date_time_base& rhs) const
427 {
428 return (*this > rhs || *this == rhs);
429 }
430
431 //! Local_date_time + date_duration
432 local_date_time_base operator+(const date_duration_type& dd) const
433 {
434 return local_date_time_base(time_system_type::add_days(this->time_,dd), zone_);
435 }
436 //! Local_date_time += date_duration
437 local_date_time_base operator+=(const date_duration_type& dd)
438 {
439 this->time_ = time_system_type::add_days(this->time_,dd);
440 return *this;
441 }
442 //! Local_date_time - date_duration
443 local_date_time_base operator-(const date_duration_type& dd) const
444 {
445 return local_date_time_base(time_system_type::subtract_days(this->time_,dd), zone_);
446 }
447 //! Local_date_time -= date_duration
448 local_date_time_base operator-=(const date_duration_type& dd)
449 {
450 this->time_ = time_system_type::subtract_days(this->time_,dd);
451 return *this;
452 }
453 //! Local_date_time + time_duration
454 local_date_time_base operator+(const time_duration_type& td) const
455 {
456 return local_date_time_base(time_system_type::add_time_duration(this->time_,td), zone_);
457 }
458 //! Local_date_time += time_duration
459 local_date_time_base operator+=(const time_duration_type& td)
460 {
461 this->time_ = time_system_type::add_time_duration(this->time_,td);
462 return *this;
463 }
464 //! Local_date_time - time_duration
465 local_date_time_base operator-(const time_duration_type& td) const
466 {
467 return local_date_time_base(time_system_type::subtract_time_duration(this->time_,td), zone_);
468 }
469 //! Local_date_time -= time_duration
470 local_date_time_base operator-=(const time_duration_type& td)
471 {
472 this->time_ = time_system_type::subtract_time_duration(this->time_,td);
473 return *this;
474 }
475 //! local_date_time -= local_date_time --> time_duration_type
476 time_duration_type operator-(const local_date_time_base& rhs) const
477 {
478 return utc_time_type(this->time_) - utc_time_type(rhs.time_);
479 }
480 private:
481 boost::shared_ptr<tz_type> zone_;
482 //bool is_dst_;
483
484 /*! Adjust the passed in time to UTC?
485 */
486 utc_time_type construction_adjustment(utc_time_type t,
487 boost::shared_ptr<tz_type> z,
488 bool dst_flag)
489 {
490 if(z != boost::shared_ptr<tz_type>()) {
491 if(dst_flag && z->has_dst()) {
492 t -= z->dst_offset();
493 } // else no adjust
494 t -= z->base_utc_offset();
495 }
496 return t;
497 }
498
499 /*! Simple formatting code -- todo remove this?
500 */
501 std::string zone_as_offset(const time_duration_type& td,
502 const std::string& separator) const
503 {
504 std::ostringstream ss;
505 if(td.is_negative()) {
506 // a negative duration is represented as "-[h]h:mm"
507 // we require two digits for the hour. A positive duration
508 // with the %H flag will always give two digits
509 ss << "-";
510 }
511 else {
512 ss << "+";
513 }
514 ss << std::setw(2) << std::setfill('0')
515 << date_time::absolute_value(td.hours())
516 << separator
517 << std::setw(2) << std::setfill('0')
518 << date_time::absolute_value(td.minutes());
519 return ss.str();
520 }
521 };
522
523 //!Use the default parameters to define local_date_time
524 typedef local_date_time_base<> local_date_time;
525
526} }
527
528
529#endif
530

source code of boost/libs/date_time/include/boost/date_time/local_time/local_date_time.hpp