1//
2// DateTime.h
3//
4// Library: Foundation
5// Package: DateTime
6// Module: DateTime
7//
8// Definition of the DateTime class.
9//
10// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
11// and Contributors.
12//
13// SPDX-License-Identifier: BSL-1.0
14//
15
16
17#ifndef Foundation_DateTime_INCLUDED
18#define Foundation_DateTime_INCLUDED
19
20
21#include "Poco/Foundation.h"
22#include "Poco/Timestamp.h"
23#include "Poco/Timespan.h"
24
25
26struct tm;
27
28
29namespace Poco {
30
31
32class Foundation_API DateTime
33 /// This class represents an instant in time, expressed
34 /// in years, months, days, hours, minutes, seconds
35 /// and milliseconds based on the Gregorian calendar.
36 /// The class is mainly useful for conversions between
37 /// UTC, Julian day and Gregorian calendar dates.
38 ///
39 /// The date and time stored in a DateTime is always in UTC
40 /// (Coordinated Universal Time) and thus independent of the
41 /// timezone in effect on the system.
42 ///
43 /// Conversion calculations are based on algorithms
44 /// collected and described by Peter Baum at
45 /// http://vsg.cape.com/~pbaum/date/date0.htm
46 ///
47 /// Internally, this class stores a date/time in two
48 /// forms (UTC and broken down) for performance reasons. Only use
49 /// this class for conversions between date/time representations.
50 /// Use the Timestamp class for everything else.
51 ///
52 /// Notes:
53 /// * Zero is a valid year (in accordance with ISO 8601 and astronomical year numbering)
54 /// * Year zero (0) is a leap year
55 /// * Negative years (years preceding 1 BC) are not supported
56 ///
57 /// For more information, please see:
58 /// * http://en.wikipedia.org/wiki/Gregorian_Calendar
59 /// * http://en.wikipedia.org/wiki/Julian_day
60 /// * http://en.wikipedia.org/wiki/UTC
61 /// * http://en.wikipedia.org/wiki/ISO_8601
62{
63public:
64 enum Months
65 /// Symbolic names for month numbers (1 to 12).
66 {
67 JANUARY = 1,
68 FEBRUARY,
69 MARCH,
70 APRIL,
71 MAY,
72 JUNE,
73 JULY,
74 AUGUST,
75 SEPTEMBER,
76 OCTOBER,
77 NOVEMBER,
78 DECEMBER
79 };
80
81 enum DaysOfWeek
82 /// Symbolic names for week day numbers (0 to 6).
83 {
84 SUNDAY = 0,
85 MONDAY,
86 TUESDAY,
87 WEDNESDAY,
88 THURSDAY,
89 FRIDAY,
90 SATURDAY
91 };
92
93 DateTime();
94 /// Creates a DateTime for the current date and time.
95
96 DateTime(const tm& tmStruct);
97 /// Creates a DateTime from tm struct.
98
99 DateTime(const Timestamp& timestamp);
100 /// Creates a DateTime for the date and time given in
101 /// a Timestamp.
102
103 DateTime(int year, int month, int day, int hour = 0, int minute = 0, int second = 0, int millisecond = 0, int microsecond = 0);
104 /// Creates a DateTime for the given Gregorian date and time.
105 /// * year is from 0 to 9999.
106 /// * month is from 1 to 12.
107 /// * day is from 1 to 31.
108 /// * hour is from 0 to 23.
109 /// * minute is from 0 to 59.
110 /// * second is from 0 to 60.
111 /// * millisecond is from 0 to 999.
112 /// * microsecond is from 0 to 999.
113 /// Throws an InvalidArgumentException if an argument date is out of range.
114
115 DateTime(double julianDay);
116 /// Creates a DateTime for the given Julian day.
117
118 DateTime(Timestamp::UtcTimeVal utcTime, Timestamp::TimeDiff diff);
119 /// Creates a DateTime from an UtcTimeVal and a TimeDiff.
120 ///
121 /// Mainly used internally by DateTime and friends.
122
123 DateTime(const DateTime& dateTime);
124 /// Copy constructor. Creates the DateTime from another one.
125
126 ~DateTime();
127 /// Destroys the DateTime.
128
129 DateTime& operator = (const DateTime& dateTime);
130 /// Assigns another DateTime.
131
132 DateTime& operator = (const Timestamp& timestamp);
133 /// Assigns a Timestamp.
134
135 DateTime& operator = (double julianDay);
136 /// Assigns a Julian day.
137
138 DateTime& assign(int year, int month, int day, int hour = 0, int minute = 0, int second = 0, int millisecond = 0, int microseconds = 0);
139 /// Assigns a Gregorian date and time.
140 /// * year is from 0 to 9999.
141 /// * month is from 1 to 12.
142 /// * day is from 1 to 31.
143 /// * hour is from 0 to 23.
144 /// * minute is from 0 to 59.
145 /// * second is from 0 to 60.
146 /// * millisecond is from 0 to 999.
147 /// * microsecond is from 0 to 999.
148 /// Throws an InvalidArgumentException if an argument date is out of range.
149
150 void swap(DateTime& dateTime);
151 /// Swaps the DateTime with another one.
152
153 int year() const;
154 /// Returns the year.
155
156 int month() const;
157 /// Returns the month (1 to 12).
158
159 int week(int firstDayOfWeek = MONDAY) const;
160 /// Returns the week number within the year.
161 /// FirstDayOfWeek should be either SUNDAY (0) or MONDAY (1).
162 /// The returned week number will be from 0 to 53. Week number 1 is the week
163 /// containing January 4. This is in accordance to ISO 8601.
164 ///
165 /// The following example assumes that firstDayOfWeek is MONDAY. For 2005, which started
166 /// on a Saturday, week 1 will be the week starting on Monday, January 3.
167 /// January 1 and 2 will fall within week 0 (or the last week of the previous year).
168 ///
169 /// For 2007, which starts on a Monday, week 1 will be the week starting on Monday, January 1.
170 /// There will be no week 0 in 2007.
171
172 int day() const;
173 /// Returns the day within the month (1 to 31).
174
175 int dayOfWeek() const;
176 /// Returns the weekday (0 to 6, where
177 /// 0 = Sunday, 1 = Monday, ..., 6 = Saturday).
178
179 int dayOfYear() const;
180 /// Returns the number of the day in the year.
181 /// January 1 is 1, February 1 is 32, etc.
182
183 int hour() const;
184 /// Returns the hour (0 to 23).
185
186 int hourAMPM() const;
187 /// Returns the hour (0 to 12).
188
189 bool isAM() const;
190 /// Returns true if hour < 12;
191
192 bool isPM() const;
193 /// Returns true if hour >= 12.
194
195 int minute() const;
196 /// Returns the minute (0 to 59).
197
198 int second() const;
199 /// Returns the second (0 to 59).
200
201 int millisecond() const;
202 /// Returns the millisecond (0 to 999)
203
204 int microsecond() const;
205 /// Returns the microsecond (0 to 999)
206
207 double julianDay() const;
208 /// Returns the julian day for the date and time.
209
210 Timestamp timestamp() const;
211 /// Returns the date and time expressed as a Timestamp.
212
213 Timestamp::UtcTimeVal utcTime() const;
214 /// Returns the date and time expressed in UTC-based
215 /// time. UTC base time is midnight, October 15, 1582.
216 /// Resolution is 100 nanoseconds.
217
218 bool operator == (const DateTime& dateTime) const;
219 bool operator != (const DateTime& dateTime) const;
220 bool operator < (const DateTime& dateTime) const;
221 bool operator <= (const DateTime& dateTime) const;
222 bool operator > (const DateTime& dateTime) const;
223 bool operator >= (const DateTime& dateTime) const;
224
225 DateTime operator + (const Timespan& span) const;
226 DateTime operator - (const Timespan& span) const;
227 Timespan operator - (const DateTime& dateTime) const;
228 DateTime& operator += (const Timespan& span);
229 DateTime& operator -= (const Timespan& span);
230
231 tm makeTM() const;
232 /// Converts DateTime to tm struct.
233
234 void makeUTC(int tzd);
235 /// Converts a local time into UTC, by applying the given time zone differential.
236
237 void makeLocal(int tzd);
238 /// Converts a UTC time into a local time, by applying the given time zone differential.
239
240 static bool isLeapYear(int year);
241 /// Returns true if the given year is a leap year;
242 /// false otherwise.
243
244 static int daysOfMonth(int year, int month);
245 /// Returns the number of days in the given month
246 /// and year. Month is from 1 to 12.
247
248 static bool isValid(int year, int month, int day, int hour = 0, int minute = 0, int second = 0, int millisecond = 0, int microsecond = 0);
249 /// Checks if the given date and time is valid
250 /// (all arguments are within a proper range).
251 ///
252 /// Returns true if all arguments are valid, false otherwise.
253
254protected:
255 static double toJulianDay(Timestamp::UtcTimeVal utcTime);
256 /// Computes the Julian day for an UTC time.
257
258 static double toJulianDay(int year, int month, int day, int hour = 0, int minute = 0, int second = 0, int millisecond = 0, int microsecond = 0);
259 /// Computes the Julian day for a Gregorian calendar date and time.
260 /// See <http://vsg.cape.com/~pbaum/date/jdimp.htm>, section 2.3.1 for the algorithm.
261
262 static Timestamp::UtcTimeVal toUtcTime(double julianDay);
263 /// Computes the UTC time for a Julian day.
264
265 void computeGregorian(double julianDay);
266 /// Computes the Gregorian date for the given Julian day.
267 /// See <http://vsg.cape.com/~pbaum/date/injdimp.htm>, section 3.3.1 for the algorithm.
268
269 void computeDaytime();
270 /// Extracts the daytime (hours, minutes, seconds, etc.) from the stored utcTime.
271
272private:
273 void checkLimit(short& lower, short& higher, short limit);
274 void normalize();
275 ///utility functions used to correct the overflow in computeGregorian
276
277 Timestamp::UtcTimeVal _utcTime;
278 short _year;
279 short _month;
280 short _day;
281 short _hour;
282 short _minute;
283 short _second;
284 short _millisecond;
285 short _microsecond;
286};
287
288
289//
290// inlines
291//
292
293
294inline double DateTime::toJulianDay(Timestamp::UtcTimeVal utcTime)
295{
296 double utcDays = double(utcTime)/864000000000.0;
297 return utcDays + 2299160.5; // first day of Gregorian reform (Oct 15 1582)
298}
299
300
301inline Timestamp::UtcTimeVal DateTime::toUtcTime(double julianDay)
302{
303 return Timestamp::UtcTimeVal((julianDay - 2299160.5)*864000000000.0);
304}
305
306
307inline Timestamp DateTime::timestamp() const
308{
309 return Timestamp::fromUtcTime(_utcTime);
310}
311
312
313inline Timestamp::UtcTimeVal DateTime::utcTime() const
314{
315 return _utcTime;
316}
317
318
319inline int DateTime::year() const
320{
321 return _year;
322}
323
324
325inline int DateTime::month() const
326{
327 return _month;
328}
329
330
331inline int DateTime::day() const
332{
333 return _day;
334}
335
336
337inline int DateTime::hour() const
338{
339 return _hour;
340}
341
342
343inline int DateTime::hourAMPM() const
344{
345 if (_hour < 1)
346 return 12;
347 else if (_hour > 12)
348 return _hour - 12;
349 else
350 return _hour;
351}
352
353
354inline bool DateTime::isAM() const
355{
356 return _hour < 12;
357}
358
359
360inline bool DateTime::isPM() const
361{
362 return _hour >= 12;
363}
364
365
366inline int DateTime::minute() const
367{
368 return _minute;
369}
370
371
372inline int DateTime::second() const
373{
374 return _second;
375}
376
377
378inline int DateTime::millisecond() const
379{
380 return _millisecond;
381}
382
383
384inline int DateTime::microsecond() const
385{
386 return _microsecond;
387}
388
389
390inline bool DateTime::operator == (const DateTime& dateTime) const
391{
392 return _utcTime == dateTime._utcTime;
393}
394
395
396inline bool DateTime::operator != (const DateTime& dateTime) const
397{
398 return _utcTime != dateTime._utcTime;
399}
400
401
402inline bool DateTime::operator < (const DateTime& dateTime) const
403{
404 return _utcTime < dateTime._utcTime;
405}
406
407
408inline bool DateTime::operator <= (const DateTime& dateTime) const
409{
410 return _utcTime <= dateTime._utcTime;
411}
412
413
414inline bool DateTime::operator > (const DateTime& dateTime) const
415{
416 return _utcTime > dateTime._utcTime;
417}
418
419
420inline bool DateTime::operator >= (const DateTime& dateTime) const
421{
422 return _utcTime >= dateTime._utcTime;
423}
424
425
426inline bool DateTime::isLeapYear(int year)
427{
428 return (year % 4) == 0 && ((year % 100) != 0 || (year % 400) == 0);
429}
430
431
432inline void swap(DateTime& d1, DateTime& d2)
433{
434 d1.swap(d2);
435}
436
437
438} // namespace Poco
439
440
441#endif // Foundation_DateTime_INCLUDED
442