1 #
2 # Copyright (c) 2001 Bizar Software Pty Ltd (http://www.bizarsoftware.com.au/)
3 # This module is free software, and you may redistribute it and/or modify
4 # under the same terms as Python, so long as this copyright message and
5 # disclaimer are retained in their original form.
6 #
7 # IN NO EVENT SHALL BIZAR SOFTWARE PTY LTD BE LIABLE TO ANY PARTY FOR
8 # DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING
9 # OUT OF THE USE OF THIS CODE, EVEN IF THE AUTHOR HAS BEEN ADVISED OF THE
10 # POSSIBILITY OF SUCH DAMAGE.
11 #
12 # BIZAR SOFTWARE PTY LTD SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
13 # BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
14 # FOR A PARTICULAR PURPOSE. THE CODE PROVIDED HEREUNDER IS ON AN "AS IS"
15 # BASIS, AND THERE IS NO OBLIGATION WHATSOEVER TO PROVIDE MAINTENANCE,
16 # SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
17 #
18 # $Id: date.py,v 1.38 2002-12-16 04:39:36 richard Exp $
20 __doc__ = """
21 Date, time and time interval handling.
22 """
24 import time, re, calendar
25 from i18n import _
27 class Date:
28 '''
29 As strings, date-and-time stamps are specified with the date in
30 international standard format (yyyy-mm-dd) joined to the time
31 (hh:mm:ss) by a period ("."). Dates in this form can be easily compared
32 and are fairly readable when printed. An example of a valid stamp is
33 "2000-06-24.13:03:59". We'll call this the "full date format". When
34 Timestamp objects are printed as strings, they appear in the full date
35 format with the time always given in GMT. The full date format is
36 always exactly 19 characters long.
38 For user input, some partial forms are also permitted: the whole time
39 or just the seconds may be omitted; and the whole date may be omitted
40 or just the year may be omitted. If the time is given, the time is
41 interpreted in the user's local time zone. The Date constructor takes
42 care of these conversions. In the following examples, suppose that yyyy
43 is the current year, mm is the current month, and dd is the current day
44 of the month; and suppose that the user is on Eastern Standard Time.
46 "2000-04-17" means <Date 2000-04-17.00:00:00>
47 "01-25" means <Date yyyy-01-25.00:00:00>
48 "2000-04-17.03:45" means <Date 2000-04-17.08:45:00>
49 "08-13.22:13" means <Date yyyy-08-14.03:13:00>
50 "11-07.09:32:43" means <Date yyyy-11-07.14:32:43>
51 "14:25" means <Date yyyy-mm-dd.19:25:00>
52 "8:47:11" means <Date yyyy-mm-dd.13:47:11>
53 "." means "right now"
55 The Date class should understand simple date expressions of the form
56 stamp + interval and stamp - interval. When adding or subtracting
57 intervals involving months or years, the components are handled
58 separately. For example, when evaluating "2000-06-25 + 1m 10d", we
59 first add one month to get 2000-07-25, then add 10 days to get
60 2000-08-04 (rather than trying to decide whether 1m 10d means 38 or 40
61 or 41 days).
63 Example usage:
64 >>> Date(".")
65 <Date 2000-06-26.00:34:02>
66 >>> _.local(-5)
67 "2000-06-25.19:34:02"
68 >>> Date(". + 2d")
69 <Date 2000-06-28.00:34:02>
70 >>> Date("1997-04-17", -5)
71 <Date 1997-04-17.00:00:00>
72 >>> Date("01-25", -5)
73 <Date 2000-01-25.00:00:00>
74 >>> Date("08-13.22:13", -5)
75 <Date 2000-08-14.03:13:00>
76 >>> Date("14:25", -5)
77 <Date 2000-06-25.19:25:00>
79 The date format 'yyyymmddHHMMSS' (year, month, day, hour,
80 minute, second) is the serialisation format returned by the serialise()
81 method, and is accepted as an argument on instatiation.
82 '''
83 def __init__(self, spec='.', offset=0):
84 """Construct a date given a specification and a time zone offset.
86 'spec' is a full date or a partial form, with an optional
87 added or subtracted interval. Or a date 9-tuple.
88 'offset' is the local time zone offset from GMT in hours.
89 """
90 if type(spec) == type(''):
91 self.set(spec, offset=offset)
92 else:
93 y,m,d,H,M,S,x,x,x = spec
94 ts = calendar.timegm((y,m,d,H+offset,M,S,0,0,0))
95 self.year, self.month, self.day, self.hour, self.minute, \
96 self.second, x, x, x = time.gmtime(ts)
98 def addInterval(self, interval):
99 ''' Add the interval to this date, returning the date tuple
100 '''
101 # do the basic calc
102 sign = interval.sign
103 year = self.year + sign * interval.year
104 month = self.month + sign * interval.month
105 day = self.day + sign * interval.day
106 hour = self.hour + sign * interval.hour
107 minute = self.minute + sign * interval.minute
108 second = self.second + sign * interval.second
110 # now cope with under- and over-flow
111 # first do the time
112 while (second < 0 or second > 59 or minute < 0 or minute > 59 or
113 hour < 0 or hour > 59):
114 if second < 0: minute -= 1; second += 60
115 elif second > 59: minute += 1; second -= 60
116 if minute < 0: hour -= 1; minute += 60
117 elif minute > 59: hour += 1; minute -= 60
118 if hour < 0: day -= 1; hour += 24
119 elif hour > 59: day += 1; hour -= 24
121 # fix up the month so we're within range
122 while month < 1 or month > 12:
123 if month < 1: year -= 1; month += 12
124 if month > 12: year += 1; month -= 12
126 # now do the days, now that we know what month we're in
127 mdays = calendar.mdays
128 if month == 2 and calendar.isleap(year): month_days = 29
129 else: month_days = mdays[month]
130 while month < 1 or month > 12 or day < 0 or day > month_days:
131 # now to day under/over
132 if day < 0: month -= 1; day += month_days
133 elif day > month_days: month += 1; day -= month_days
135 # possibly fix up the month so we're within range
136 while month < 1 or month > 12:
137 if month < 1: year -= 1; month += 12
138 if month > 12: year += 1; month -= 12
140 # re-figure the number of days for this month
141 if month == 2 and calendar.isleap(year): month_days = 29
142 else: month_days = mdays[month]
143 return (year, month, day, hour, minute, second, 0, 0, 0)
145 def applyInterval(self, interval):
146 ''' Apply the interval to this date
147 '''
148 self.year, self.month, self.day, self.hour, self.minute, \
149 self.second, x, x, x = self.addInterval(interval)
151 def __add__(self, interval):
152 """Add an interval to this date to produce another date.
153 """
154 return Date(self.addInterval(interval))
156 # deviates from spec to allow subtraction of dates as well
157 def __sub__(self, other):
158 """ Subtract:
159 1. an interval from this date to produce another date.
160 2. a date from this date to produce an interval.
161 """
162 if isinstance(other, Interval):
163 other = Interval(other.get_tuple())
164 other.sign *= -1
165 return self.__add__(other)
167 assert isinstance(other, Date), 'May only subtract Dates or Intervals'
169 # TODO this code will fall over laughing if the dates cross
170 # leap years, phases of the moon, ....
171 a = calendar.timegm((self.year, self.month, self.day, self.hour,
172 self.minute, self.second, 0, 0, 0))
173 b = calendar.timegm((other.year, other.month, other.day,
174 other.hour, other.minute, other.second, 0, 0, 0))
175 diff = a - b
176 if diff < 0:
177 sign = 1
178 diff = -diff
179 else:
180 sign = -1
181 S = diff%60
182 M = (diff/60)%60
183 H = (diff/(60*60))%60
184 if H>1: S = 0
185 d = (diff/(24*60*60))%30
186 if d>1: H = S = M = 0
187 m = (diff/(30*24*60*60))%12
188 if m>1: H = S = M = 0
189 y = (diff/(365*24*60*60))
190 if y>1: d = H = S = M = 0
191 return Interval((y, m, d, H, M, S), sign=sign)
193 def __cmp__(self, other):
194 """Compare this date to another date."""
195 if other is None:
196 return 1
197 for attr in ('year', 'month', 'day', 'hour', 'minute', 'second'):
198 if not hasattr(other, attr):
199 return 1
200 r = cmp(getattr(self, attr), getattr(other, attr))
201 if r: return r
202 return 0
204 def __str__(self):
205 """Return this date as a string in the yyyy-mm-dd.hh:mm:ss format."""
206 return '%4d-%02d-%02d.%02d:%02d:%02d'%(self.year, self.month, self.day,
207 self.hour, self.minute, self.second)
209 def pretty(self, format='%d %B %Y'):
210 ''' print up the date date using a pretty format...
212 Note that if the day is zero, and the day appears first in the
213 format, then the day number will be removed from output.
214 '''
215 str = time.strftime(format, (self.year, self.month, self.day,
216 self.hour, self.minute, self.second, 0, 0, 0))
217 # handle zero day by removing it
218 if format.startswith('%d') and str[0] == '0':
219 return ' ' + str[1:]
220 return str
222 def set(self, spec, offset=0, date_re=re.compile(r'''
223 (((?P<y>\d\d\d\d)-)?((?P<m>\d\d?)-(?P<d>\d\d?))?)? # yyyy-mm-dd
224 (?P<n>\.)? # .
225 (((?P<H>\d?\d):(?P<M>\d\d))?(:(?P<S>\d\d))?)? # hh:mm:ss
226 (?P<o>.+)? # offset
227 ''', re.VERBOSE), serialised_re=re.compile(r'''
228 (\d{4})(\d\d)(\d\d)(\d\d)(\d\d)(\d\d)
229 ''', re.VERBOSE)):
230 ''' set the date to the value in spec
231 '''
232 m = serialised_re.match(spec)
233 if m is not None:
234 # we're serialised - easy!
235 self.year, self.month, self.day, self.hour, self.minute, \
236 self.second = map(int, m.groups()[:6])
237 return
239 # not serialised data, try usual format
240 m = date_re.match(spec)
241 if m is None:
242 raise ValueError, _('Not a date spec: [[yyyy-]mm-dd].'
243 '[[h]h:mm[:ss]][offset]')
245 info = m.groupdict()
247 # get the current date as our default
248 y,m,d = time.gmtime(time.time())[:3]
250 # time defaults to 00:00:00 _always_
251 H = M = S = 0
253 # override year, month, day parts
254 if info['m'] is not None and info['d'] is not None:
255 m = int(info['m'])
256 d = int(info['d'])
257 if info['y'] is not None:
258 y = int(info['y'])
260 # override hour, minute, second parts
261 if info['H'] is not None and info['M'] is not None:
262 H = int(info['H']) - offset
263 M = int(info['M'])
264 S = 0
265 if info['S'] is not None: S = int(info['S'])
267 # now handle the adjustment of hour
268 ts = calendar.timegm((y,m,d,H,M,S,0,0,0))
269 self.year, self.month, self.day, self.hour, self.minute, \
270 self.second, x, x, x = time.gmtime(ts)
272 if info.get('o', None):
273 self.applyInterval(Interval(info['o']))
275 def __repr__(self):
276 return '<Date %s>'%self.__str__()
278 def local(self, offset):
279 """ Return this date as yyyy-mm-dd.hh:mm:ss in a local time zone.
280 """
281 return Date((self.year, self.month, self.day, self.hour + offset,
282 self.minute, self.second, 0, 0, 0))
284 def get_tuple(self):
285 return (self.year, self.month, self.day, self.hour, self.minute,
286 self.second, 0, 0, 0)
288 def serialise(self):
289 return '%4d%02d%02d%02d%02d%02d'%(self.year, self.month,
290 self.day, self.hour, self.minute, self.second)
292 class Interval:
293 '''
294 Date intervals are specified using the suffixes "y", "m", and "d". The
295 suffix "w" (for "week") means 7 days. Time intervals are specified in
296 hh:mm:ss format (the seconds may be omitted, but the hours and minutes
297 may not).
299 "3y" means three years
300 "2y 1m" means two years and one month
301 "1m 25d" means one month and 25 days
302 "2w 3d" means two weeks and three days
303 "1d 2:50" means one day, two hours, and 50 minutes
304 "14:00" means 14 hours
305 "0:04:33" means four minutes and 33 seconds
307 Example usage:
308 >>> Interval(" 3w 1 d 2:00")
309 <Interval 22d 2:00>
310 >>> Date(". + 2d") + Interval("- 3w")
311 <Date 2000-06-07.00:34:02>
313 Intervals are added/subtracted in order of:
314 seconds, minutes, hours, years, months, days
316 Calculations involving monts (eg '+2m') have no effect on days - only
317 days (or over/underflow from hours/mins/secs) will do that, and
318 days-per-month and leap years are accounted for. Leap seconds are not.
320 The interval format 'syyyymmddHHMMSS' (sign, year, month, day, hour,
321 minute, second) is the serialisation format returned by the serialise()
322 method, and is accepted as an argument on instatiation.
324 TODO: more examples, showing the order of addition operation
325 '''
326 def __init__(self, spec, sign=1):
327 """Construct an interval given a specification."""
328 if type(spec) == type(''):
329 self.set(spec)
330 else:
331 if len(spec) == 7:
332 self.sign, self.year, self.month, self.day, self.hour, \
333 self.minute, self.second = spec
334 else:
335 # old, buggy spec form
336 self.sign = sign
337 self.year, self.month, self.day, self.hour, self.minute, \
338 self.second = spec
340 def __cmp__(self, other):
341 """Compare this interval to another interval."""
342 if other is None:
343 return 1
344 for attr in ('year', 'month', 'day', 'hour', 'minute', 'second'):
345 if not hasattr(other, attr):
346 return 1
347 r = cmp(getattr(self, attr), getattr(other, attr))
348 if r: return r
349 return 0
351 def __str__(self):
352 """Return this interval as a string."""
353 sign = {1:'+', -1:'-'}[self.sign]
354 l = [sign]
355 if self.year: l.append('%sy'%self.year)
356 if self.month: l.append('%sm'%self.month)
357 if self.day: l.append('%sd'%self.day)
358 if self.second:
359 l.append('%d:%02d:%02d'%(self.hour, self.minute, self.second))
360 elif self.hour or self.minute:
361 l.append('%d:%02d'%(self.hour, self.minute))
362 return ' '.join(l)
364 def __add__(self, other):
365 if isinstance(other, Date):
366 # the other is a Date - produce a Date
367 return Date(other.addInterval(self))
368 elif isinstance(other, Interval):
369 # add the other Interval to this one
370 a = self.get_tuple()
371 b = other.get_tuple()
372 if b[0] < 0:
373 i = Interval([x-y for x,y in zip(a[1:],b[1:])])
374 else:
375 i = Interval([x+y for x,y in zip(a[1:],b[1:])])
376 return i
377 # nope, no idea what to do with this other...
378 raise TypeError, "Can't add %r"%other
380 def set(self, spec, interval_re=re.compile('''
381 \s*(?P<s>[-+])? # + or -
382 \s*((?P<y>\d+\s*)y)? # year
383 \s*((?P<m>\d+\s*)m)? # month
384 \s*((?P<w>\d+\s*)w)? # week
385 \s*((?P<d>\d+\s*)d)? # day
386 \s*(((?P<H>\d+):(?P<M>\d+))?(:(?P<S>\d+))?)? # time
387 \s*''', re.VERBOSE), serialised_re=re.compile('''
388 (?P<s>[+-])?1?(?P<y>([ ]{3}\d|\d{4}))(?P<m>\d{2})(?P<d>\d{2})
389 (?P<H>\d{2})(?P<M>\d{2})(?P<S>\d{2})''', re.VERBOSE)):
390 ''' set the date to the value in spec
391 '''
392 self.year = self.month = self.week = self.day = self.hour = \
393 self.minute = self.second = 0
394 self.sign = 1
395 m = serialised_re.match(spec)
396 if not m:
397 m = interval_re.match(spec)
398 if not m:
399 raise ValueError, _('Not an interval spec: [+-] [#y] [#m] [#w] '
400 '[#d] [[[H]H:MM]:SS]')
402 info = m.groupdict()
403 for group, attr in {'y':'year', 'm':'month', 'w':'week', 'd':'day',
404 'H':'hour', 'M':'minute', 'S':'second'}.items():
405 if info.get(group, None) is not None:
406 setattr(self, attr, int(info[group]))
408 if self.week:
409 self.day = self.day + self.week*7
411 if info['s'] is not None:
412 self.sign = {'+':1, '-':-1}[info['s']]
414 def __repr__(self):
415 return '<Interval %s>'%self.__str__()
417 def pretty(self):
418 ''' print up the date date using one of these nice formats..
419 '''
420 if self.year:
421 if self.year == 1:
422 return _('1 year')
423 else:
424 return _('%(number)s years')%{'number': self.year}
425 elif self.month or self.day > 13:
426 days = (self.month * 30) + self.day
427 if days > 28:
428 if int(days/30) > 1:
429 s = _('%(number)s months')%{'number': int(days/30)}
430 else:
431 s = _('1 month')
432 else:
433 s = _('%(number)s weeks')%{'number': int(days/7)}
434 elif self.day > 7:
435 s = _('1 week')
436 elif self.day > 1:
437 s = _('%(number)s days')%{'number': self.day}
438 elif self.day == 1 or self.hour > 12:
439 if self.sign > 0:
440 return _('tomorrow')
441 else:
442 return _('yesterday')
443 elif self.hour > 1:
444 s = _('%(number)s hours')%{'number': self.hour}
445 elif self.hour == 1:
446 if self.minute < 15:
447 s = _('an hour')
448 elif self.minute/15 == 2:
449 s = _('1 1/2 hours')
450 else:
451 s = _('1 %(number)s/4 hours')%{'number': self.minute/15}
452 elif self.minute < 1:
453 if self.sign > 0:
454 return _('in a moment')
455 else:
456 return _('just now')
457 elif self.minute == 1:
458 s = _('1 minute')
459 elif self.minute < 15:
460 s = _('%(number)s minutes')%{'number': self.minute}
461 elif int(self.minute/15) == 2:
462 s = _('1/2 an hour')
463 else:
464 s = _('%(number)s/4 hour')%{'number': int(self.minute/15)}
465 return s
467 def get_tuple(self):
468 return (self.sign, self.year, self.month, self.day, self.hour,
469 self.minute, self.second)
471 def serialise(self):
472 sign = self.sign > 0 and '+' or '-'
473 return '%s%04d%02d%02d%02d%02d%02d'%(sign, self.year, self.month,
474 self.day, self.hour, self.minute, self.second)
477 def test():
478 intervals = (" 3w 1 d 2:00", " + 2d", "3w")
479 for interval in intervals:
480 print '>>> Interval("%s")'%interval
481 print `Interval(interval)`
483 dates = (".", "2000-06-25.19:34:02", ". + 2d", "1997-04-17", "01-25",
484 "08-13.22:13", "14:25")
485 for date in dates:
486 print '>>> Date("%s")'%date
487 print `Date(date)`
489 sums = ((". + 2d", "3w"), (".", " 3w 1 d 2:00"))
490 for date, interval in sums:
491 print '>>> Date("%s") + Interval("%s")'%(date, interval)
492 print `Date(date) + Interval(interval)`
494 if __name__ == '__main__':
495 test()
497 # vim: set filetype=python ts=4 sw=4 et si