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Diffstat (limited to 'Doc/includes/tzinfo-examples.py')
| -rw-r--r-- | Doc/includes/tzinfo-examples.py | 175 |
1 files changed, 0 insertions, 175 deletions
diff --git a/Doc/includes/tzinfo-examples.py b/Doc/includes/tzinfo-examples.py deleted file mode 100644 index ae5a509266..0000000000 --- a/Doc/includes/tzinfo-examples.py +++ /dev/null @@ -1,175 +0,0 @@ -from datetime import tzinfo, timedelta, datetime, timezone - -ZERO = timedelta(0) -HOUR = timedelta(hours=1) -SECOND = timedelta(seconds=1) - -# A class capturing the platform's idea of local time. -# (May result in wrong values on historical times in -# timezones where UTC offset and/or the DST rules had -# changed in the past.) -import time as _time - -STDOFFSET = timedelta(seconds = -_time.timezone) -if _time.daylight: - DSTOFFSET = timedelta(seconds = -_time.altzone) -else: - DSTOFFSET = STDOFFSET - -DSTDIFF = DSTOFFSET - STDOFFSET - -class LocalTimezone(tzinfo): - - def fromutc(self, dt): - assert dt.tzinfo is self - stamp = (dt - datetime(1970, 1, 1, tzinfo=self)) // SECOND - args = _time.localtime(stamp)[:6] - dst_diff = DSTDIFF // SECOND - # Detect fold - fold = (args == _time.localtime(stamp - dst_diff)) - return datetime(*args, microsecond=dt.microsecond, - tzinfo=self, fold=fold) - - def utcoffset(self, dt): - if self._isdst(dt): - return DSTOFFSET - else: - return STDOFFSET - - def dst(self, dt): - if self._isdst(dt): - return DSTDIFF - else: - return ZERO - - def tzname(self, dt): - return _time.tzname[self._isdst(dt)] - - def _isdst(self, dt): - tt = (dt.year, dt.month, dt.day, - dt.hour, dt.minute, dt.second, - dt.weekday(), 0, 0) - stamp = _time.mktime(tt) - tt = _time.localtime(stamp) - return tt.tm_isdst > 0 - -Local = LocalTimezone() - - -# A complete implementation of current DST rules for major US time zones. - -def first_sunday_on_or_after(dt): - days_to_go = 6 - dt.weekday() - if days_to_go: - dt += timedelta(days_to_go) - return dt - - -# US DST Rules -# -# This is a simplified (i.e., wrong for a few cases) set of rules for US -# DST start and end times. For a complete and up-to-date set of DST rules -# and timezone definitions, visit the Olson Database (or try pytz): -# http://www.twinsun.com/tz/tz-link.htm -# http://sourceforge.net/projects/pytz/ (might not be up-to-date) -# -# In the US, since 2007, DST starts at 2am (standard time) on the second -# Sunday in March, which is the first Sunday on or after Mar 8. -DSTSTART_2007 = datetime(1, 3, 8, 2) -# and ends at 2am (DST time) on the first Sunday of Nov. -DSTEND_2007 = datetime(1, 11, 1, 2) -# From 1987 to 2006, DST used to start at 2am (standard time) on the first -# Sunday in April and to end at 2am (DST time) on the last -# Sunday of October, which is the first Sunday on or after Oct 25. -DSTSTART_1987_2006 = datetime(1, 4, 1, 2) -DSTEND_1987_2006 = datetime(1, 10, 25, 2) -# From 1967 to 1986, DST used to start at 2am (standard time) on the last -# Sunday in April (the one on or after April 24) and to end at 2am (DST time) -# on the last Sunday of October, which is the first Sunday -# on or after Oct 25. -DSTSTART_1967_1986 = datetime(1, 4, 24, 2) -DSTEND_1967_1986 = DSTEND_1987_2006 - -def us_dst_range(year): - # Find start and end times for US DST. For years before 1967, return - # start = end for no DST. - if 2006 < year: - dststart, dstend = DSTSTART_2007, DSTEND_2007 - elif 1986 < year < 2007: - dststart, dstend = DSTSTART_1987_2006, DSTEND_1987_2006 - elif 1966 < year < 1987: - dststart, dstend = DSTSTART_1967_1986, DSTEND_1967_1986 - else: - return (datetime(year, 1, 1), ) * 2 - - start = first_sunday_on_or_after(dststart.replace(year=year)) - end = first_sunday_on_or_after(dstend.replace(year=year)) - return start, end - - -class USTimeZone(tzinfo): - - def __init__(self, hours, reprname, stdname, dstname): - self.stdoffset = timedelta(hours=hours) - self.reprname = reprname - self.stdname = stdname - self.dstname = dstname - - def __repr__(self): - return self.reprname - - def tzname(self, dt): - if self.dst(dt): - return self.dstname - else: - return self.stdname - - def utcoffset(self, dt): - return self.stdoffset + self.dst(dt) - - def dst(self, dt): - if dt is None or dt.tzinfo is None: - # An exception may be sensible here, in one or both cases. - # It depends on how you want to treat them. The default - # fromutc() implementation (called by the default astimezone() - # implementation) passes a datetime with dt.tzinfo is self. - return ZERO - assert dt.tzinfo is self - start, end = us_dst_range(dt.year) - # Can't compare naive to aware objects, so strip the timezone from - # dt first. - dt = dt.replace(tzinfo=None) - if start + HOUR <= dt < end - HOUR: - # DST is in effect. - return HOUR - if end - HOUR <= dt < end: - # Fold (an ambiguous hour): use dt.fold to disambiguate. - return ZERO if dt.fold else HOUR - if start <= dt < start + HOUR: - # Gap (a non-existent hour): reverse the fold rule. - return HOUR if dt.fold else ZERO - # DST is off. - return ZERO - - def fromutc(self, dt): - assert dt.tzinfo is self - start, end = us_dst_range(dt.year) - start = start.replace(tzinfo=self) - end = end.replace(tzinfo=self) - std_time = dt + self.stdoffset - dst_time = std_time + HOUR - if end <= dst_time < end + HOUR: - # Repeated hour - return std_time.replace(fold=1) - if std_time < start or dst_time >= end: - # Standard time - return std_time - if start <= std_time < end - HOUR: - # Daylight saving time - return dst_time - - -Eastern = USTimeZone(-5, "Eastern", "EST", "EDT") -Central = USTimeZone(-6, "Central", "CST", "CDT") -Mountain = USTimeZone(-7, "Mountain", "MST", "MDT") -Pacific = USTimeZone(-8, "Pacific", "PST", "PDT") |