"Implementation of tzinfo classes for use with datetime.datetime."
import time
from datetime import timedelta,tzinfo
from django.utils.encoding import smart_unicode,smart_str,DEFAULT_LOCALE_ENCODING
class FixedOffset(tzinfo):
"Fixed offset in minutes east from UTC."
def __init__(self, offset):
if isinstance(offset, timedelta):
self.__offset = offset
offset = self.__offset.seconds // 60
else:
self.__offset = timedelta(minutes=offset)
sign = offset < 0 and '-' or '+'
self.__name = u"%s%02d%02d" % (sign, abs(offset) / 60., abs(offset) % 60)
def __repr__(self):
return self.__name
def utcoffset(self, dt):
return self.__offset
def tzname(self, dt):
return self.__name
def dst(self, dt):
return timedelta(0)
class LocalTimezone(tzinfo):
"Proxy timezone information from time module."
def __init__(self, dt):
tzinfo.__init__(self)
self._tzname = self.tzname(dt)
def __repr__(self):
return smart_str(self._tzname)
def utcoffset(self, dt):
if self._isdst(dt):
return timedelta(seconds=-time.altzone)
else:
return timedelta(seconds=-time.timezone)
def dst(self, dt):
if self._isdst(dt):
return timedelta(seconds=-time.altzone) - timedelta(seconds=-time.timezone)
else:
return timedelta(0)
def tzname(self, dt):
try:
return smart_unicode(time.tzname[self._isdst(dt)],
DEFAULT_LOCALE_ENCODING)
except UnicodeDecodeError:
return None
def _isdst(self, dt):
tt = (dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second, dt.weekday(), 0, -1)
try:
stamp = time.mktime(tt)
except (OverflowError, ValueError):
# 32 bit systems can't handle dates after Jan 2038, and certain
# systems can't handle dates before ~1901-12-01:
#
# >>> time.mktime((1900, 1, 13, 0, 0, 0, 0, 0, 0))
# OverflowError: mktime argument out of range
# >>> time.mktime((1850, 1, 13, 0, 0, 0, 0, 0, 0))
# ValueError: year out of range
#
# In this case, we fake the date, because we only care about the
# DST flag.
tt = (2037,) + tt[1:]
stamp = time.mktime(tt)
tt = time.localtime(stamp)
return tt.tm_isdst > 0
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