+++ /dev/null
-from datetime import tzinfo, timedelta, datetime
-
-ZERO = timedelta(0)
-HOUR = timedelta(hours=1)
-
-
-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; 1am standard time) on the first Sunday of Nov.
-DSTEND_2007 = datetime(1, 11, 1, 1)
-# 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; 1am standard 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, 1)
-# 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;
-# 1am standard 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
-
-
-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
-
- # Find start and end times for US DST. For years before 1967, return
- # ZERO for no DST.
- if 2006 < dt.year:
- dststart, dstend = DSTSTART_2007, DSTEND_2007
- elif 1986 < dt.year < 2007:
- dststart, dstend = DSTSTART_1987_2006, DSTEND_1987_2006
- elif 1966 < dt.year < 1987:
- dststart, dstend = DSTSTART_1967_1986, DSTEND_1967_1986
- else:
- return ZERO
-
- start = first_sunday_on_or_after(dststart.replace(year=dt.year))
- end = first_sunday_on_or_after(dstend.replace(year=dt.year))
-
- # Can't compare naive to aware objects, so strip the timezone from
- # dt first.
- if start <= dt.replace(tzinfo=None) < end:
- return HOUR
- else:
- return ZERO
-
-
-Eastern = USTimeZone(-5, "Eastern", "EST", "EDT")
-Central = USTimeZone(-6, "Central", "CST", "CDT")
-Mountain = USTimeZone(-7, "Mountain", "MST", "MDT")
-Pacific = USTimeZone(-8, "Pacific", "PST", "PDT")