1 "Implementation of tzinfo classes for use with datetime.datetime."

     2 

     3 import locale

     4 import time

     5 from datetime import timedelta, tzinfo

     6 from django.utils.encoding import smart_unicode

     7 

     8 try:

     9     DEFAULT_ENCODING = locale.getdefaultlocale()[1] or 'ascii'

    10 except:

    11     # Any problems at all determining the locale and we fallback. See #5846.

    12     DEFAULT_ENCODING = 'ascii'

    13 

    14 class FixedOffset(tzinfo):

    15     "Fixed offset in minutes east from UTC."

    16     def __init__(self, offset):

    17         self.__offset = timedelta(minutes=offset)

    18         self.__name = u"%+03d%02d" % (offset // 60, offset % 60)

    19 

    20     def __repr__(self):

    21         return self.__name

    22 

    23     def utcoffset(self, dt):

    24         return self.__offset

    25 

    26     def tzname(self, dt):

    27         return self.__name

    28 

    29     def dst(self, dt):

    30         return timedelta(0)

    31 

    32 class LocalTimezone(tzinfo):

    33     "Proxy timezone information from time module."

    34     def __init__(self, dt):

    35         tzinfo.__init__(self, dt)

    36         self._tzname = self.tzname(dt)

    37 

    38     def __repr__(self):

    39         return self._tzname

    40 

    41     def utcoffset(self, dt):

    42         if self._isdst(dt):

    43             return timedelta(seconds=-time.altzone)

    44         else:

    45             return timedelta(seconds=-time.timezone)

    46 

    47     def dst(self, dt):

    48         if self._isdst(dt):

    49             return timedelta(seconds=-time.altzone) - timedelta(seconds=-time.timezone)

    50         else:

    51             return timedelta(0)

    52 

    53     def tzname(self, dt):

    54         try:

    55             return smart_unicode(time.tzname[self._isdst(dt)], DEFAULT_ENCODING)

    56         except UnicodeDecodeError:

    57             return None

    58 

    59     def _isdst(self, dt):

    60         tt = (dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second, dt.weekday(), 0, -1)

    61         try:

    62             stamp = time.mktime(tt)

    63         except OverflowError:

    64             # 32 bit systems can't handle dates after Jan 2038, so we fake it

    65             # in that case (since we only care about the DST flag here).

    66             tt = (2037,) + tt[1:]

    67             stamp = time.mktime(tt)

    68         tt = time.localtime(stamp)

    69         return tt.tm_isdst > 0