1850 lines
61 KiB
Python
1850 lines
61 KiB
Python
# -*- coding: utf-8 -*-
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"""
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This module offers timezone implementations subclassing the abstract
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:py:class:`datetime.tzinfo` type. There are classes to handle tzfile format
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files (usually are in :file:`/etc/localtime`, :file:`/usr/share/zoneinfo`,
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etc), TZ environment string (in all known formats), given ranges (with help
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from relative deltas), local machine timezone, fixed offset timezone, and UTC
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timezone.
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"""
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import datetime
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import struct
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import time
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import sys
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import os
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import bisect
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import weakref
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from collections import OrderedDict
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import six
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from six import string_types
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from six.moves import _thread
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from ._common import tzname_in_python2, _tzinfo
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from ._common import tzrangebase, enfold
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from ._common import _validate_fromutc_inputs
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from ._factories import _TzSingleton, _TzOffsetFactory
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from ._factories import _TzStrFactory
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try:
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from .win import tzwin, tzwinlocal
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except ImportError:
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tzwin = tzwinlocal = None
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# For warning about rounding tzinfo
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from warnings import warn
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ZERO = datetime.timedelta(0)
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EPOCH = datetime.datetime.utcfromtimestamp(0)
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EPOCHORDINAL = EPOCH.toordinal()
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@six.add_metaclass(_TzSingleton)
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class tzutc(datetime.tzinfo):
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"""
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This is a tzinfo object that represents the UTC time zone.
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**Examples:**
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.. doctest::
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>>> from datetime import *
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>>> from dateutil.tz import *
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>>> datetime.now()
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datetime.datetime(2003, 9, 27, 9, 40, 1, 521290)
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>>> datetime.now(tzutc())
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datetime.datetime(2003, 9, 27, 12, 40, 12, 156379, tzinfo=tzutc())
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>>> datetime.now(tzutc()).tzname()
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'UTC'
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.. versionchanged:: 2.7.0
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``tzutc()`` is now a singleton, so the result of ``tzutc()`` will
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always return the same object.
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.. doctest::
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>>> from dateutil.tz import tzutc, UTC
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>>> tzutc() is tzutc()
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True
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>>> tzutc() is UTC
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True
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"""
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def utcoffset(self, dt):
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return ZERO
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def dst(self, dt):
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return ZERO
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@tzname_in_python2
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def tzname(self, dt):
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return "UTC"
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def is_ambiguous(self, dt):
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"""
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Whether or not the "wall time" of a given datetime is ambiguous in this
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zone.
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:param dt:
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A :py:class:`datetime.datetime`, naive or time zone aware.
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:return:
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Returns ``True`` if ambiguous, ``False`` otherwise.
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.. versionadded:: 2.6.0
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"""
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return False
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@_validate_fromutc_inputs
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def fromutc(self, dt):
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"""
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Fast track version of fromutc() returns the original ``dt`` object for
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any valid :py:class:`datetime.datetime` object.
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"""
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return dt
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def __eq__(self, other):
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if not isinstance(other, (tzutc, tzoffset)):
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return NotImplemented
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return (isinstance(other, tzutc) or
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(isinstance(other, tzoffset) and other._offset == ZERO))
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__hash__ = None
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def __ne__(self, other):
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return not (self == other)
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def __repr__(self):
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return "%s()" % self.__class__.__name__
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__reduce__ = object.__reduce__
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#: Convenience constant providing a :class:`tzutc()` instance
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#:
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#: .. versionadded:: 2.7.0
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UTC = tzutc()
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@six.add_metaclass(_TzOffsetFactory)
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class tzoffset(datetime.tzinfo):
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"""
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A simple class for representing a fixed offset from UTC.
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:param name:
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The timezone name, to be returned when ``tzname()`` is called.
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:param offset:
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The time zone offset in seconds, or (since version 2.6.0, represented
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as a :py:class:`datetime.timedelta` object).
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"""
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def __init__(self, name, offset):
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self._name = name
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try:
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# Allow a timedelta
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offset = offset.total_seconds()
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except (TypeError, AttributeError):
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pass
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self._offset = datetime.timedelta(seconds=_get_supported_offset(offset))
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def utcoffset(self, dt):
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return self._offset
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def dst(self, dt):
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return ZERO
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@tzname_in_python2
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def tzname(self, dt):
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return self._name
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@_validate_fromutc_inputs
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def fromutc(self, dt):
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return dt + self._offset
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def is_ambiguous(self, dt):
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"""
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Whether or not the "wall time" of a given datetime is ambiguous in this
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zone.
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:param dt:
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A :py:class:`datetime.datetime`, naive or time zone aware.
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:return:
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Returns ``True`` if ambiguous, ``False`` otherwise.
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.. versionadded:: 2.6.0
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"""
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return False
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def __eq__(self, other):
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if not isinstance(other, tzoffset):
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return NotImplemented
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return self._offset == other._offset
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__hash__ = None
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def __ne__(self, other):
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return not (self == other)
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def __repr__(self):
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return "%s(%s, %s)" % (self.__class__.__name__,
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repr(self._name),
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int(self._offset.total_seconds()))
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__reduce__ = object.__reduce__
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class tzlocal(_tzinfo):
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"""
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A :class:`tzinfo` subclass built around the ``time`` timezone functions.
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"""
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def __init__(self):
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super(tzlocal, self).__init__()
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self._std_offset = datetime.timedelta(seconds=-time.timezone)
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if time.daylight:
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self._dst_offset = datetime.timedelta(seconds=-time.altzone)
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else:
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self._dst_offset = self._std_offset
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self._dst_saved = self._dst_offset - self._std_offset
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self._hasdst = bool(self._dst_saved)
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self._tznames = tuple(time.tzname)
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def utcoffset(self, dt):
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if dt is None and self._hasdst:
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return None
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if self._isdst(dt):
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return self._dst_offset
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else:
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return self._std_offset
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def dst(self, dt):
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if dt is None and self._hasdst:
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return None
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if self._isdst(dt):
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return self._dst_offset - self._std_offset
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else:
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return ZERO
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@tzname_in_python2
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def tzname(self, dt):
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return self._tznames[self._isdst(dt)]
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def is_ambiguous(self, dt):
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"""
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Whether or not the "wall time" of a given datetime is ambiguous in this
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zone.
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:param dt:
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A :py:class:`datetime.datetime`, naive or time zone aware.
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:return:
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Returns ``True`` if ambiguous, ``False`` otherwise.
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.. versionadded:: 2.6.0
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"""
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naive_dst = self._naive_is_dst(dt)
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return (not naive_dst and
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(naive_dst != self._naive_is_dst(dt - self._dst_saved)))
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def _naive_is_dst(self, dt):
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timestamp = _datetime_to_timestamp(dt)
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return time.localtime(timestamp + time.timezone).tm_isdst
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def _isdst(self, dt, fold_naive=True):
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# We can't use mktime here. It is unstable when deciding if
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# the hour near to a change is DST or not.
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#
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# timestamp = time.mktime((dt.year, dt.month, dt.day, dt.hour,
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# dt.minute, dt.second, dt.weekday(), 0, -1))
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# return time.localtime(timestamp).tm_isdst
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#
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# The code above yields the following result:
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#
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# >>> import tz, datetime
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# >>> t = tz.tzlocal()
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# >>> datetime.datetime(2003,2,15,23,tzinfo=t).tzname()
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# 'BRDT'
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# >>> datetime.datetime(2003,2,16,0,tzinfo=t).tzname()
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# 'BRST'
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# >>> datetime.datetime(2003,2,15,23,tzinfo=t).tzname()
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# 'BRST'
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# >>> datetime.datetime(2003,2,15,22,tzinfo=t).tzname()
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# 'BRDT'
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# >>> datetime.datetime(2003,2,15,23,tzinfo=t).tzname()
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# 'BRDT'
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#
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# Here is a more stable implementation:
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#
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if not self._hasdst:
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return False
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# Check for ambiguous times:
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dstval = self._naive_is_dst(dt)
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fold = getattr(dt, 'fold', None)
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if self.is_ambiguous(dt):
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if fold is not None:
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return not self._fold(dt)
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else:
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return True
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return dstval
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def __eq__(self, other):
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if isinstance(other, tzlocal):
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return (self._std_offset == other._std_offset and
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self._dst_offset == other._dst_offset)
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elif isinstance(other, tzutc):
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return (not self._hasdst and
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self._tznames[0] in {'UTC', 'GMT'} and
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self._std_offset == ZERO)
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elif isinstance(other, tzoffset):
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return (not self._hasdst and
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self._tznames[0] == other._name and
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self._std_offset == other._offset)
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else:
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return NotImplemented
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__hash__ = None
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def __ne__(self, other):
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return not (self == other)
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def __repr__(self):
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return "%s()" % self.__class__.__name__
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__reduce__ = object.__reduce__
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class _ttinfo(object):
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__slots__ = ["offset", "delta", "isdst", "abbr",
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"isstd", "isgmt", "dstoffset"]
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def __init__(self):
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for attr in self.__slots__:
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setattr(self, attr, None)
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def __repr__(self):
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l = []
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for attr in self.__slots__:
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value = getattr(self, attr)
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if value is not None:
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l.append("%s=%s" % (attr, repr(value)))
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return "%s(%s)" % (self.__class__.__name__, ", ".join(l))
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def __eq__(self, other):
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if not isinstance(other, _ttinfo):
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return NotImplemented
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return (self.offset == other.offset and
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self.delta == other.delta and
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self.isdst == other.isdst and
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self.abbr == other.abbr and
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self.isstd == other.isstd and
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self.isgmt == other.isgmt and
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self.dstoffset == other.dstoffset)
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__hash__ = None
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def __ne__(self, other):
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return not (self == other)
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def __getstate__(self):
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state = {}
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for name in self.__slots__:
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state[name] = getattr(self, name, None)
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return state
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def __setstate__(self, state):
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for name in self.__slots__:
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if name in state:
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setattr(self, name, state[name])
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class _tzfile(object):
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"""
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Lightweight class for holding the relevant transition and time zone
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information read from binary tzfiles.
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"""
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attrs = ['trans_list', 'trans_list_utc', 'trans_idx', 'ttinfo_list',
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'ttinfo_std', 'ttinfo_dst', 'ttinfo_before', 'ttinfo_first']
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def __init__(self, **kwargs):
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for attr in self.attrs:
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setattr(self, attr, kwargs.get(attr, None))
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class tzfile(_tzinfo):
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"""
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This is a ``tzinfo`` subclass that allows one to use the ``tzfile(5)``
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format timezone files to extract current and historical zone information.
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:param fileobj:
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This can be an opened file stream or a file name that the time zone
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information can be read from.
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:param filename:
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This is an optional parameter specifying the source of the time zone
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information in the event that ``fileobj`` is a file object. If omitted
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and ``fileobj`` is a file stream, this parameter will be set either to
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``fileobj``'s ``name`` attribute or to ``repr(fileobj)``.
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See `Sources for Time Zone and Daylight Saving Time Data
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<https://data.iana.org/time-zones/tz-link.html>`_ for more information.
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Time zone files can be compiled from the `IANA Time Zone database files
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<https://www.iana.org/time-zones>`_ with the `zic time zone compiler
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<https://www.freebsd.org/cgi/man.cgi?query=zic&sektion=8>`_
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.. note::
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Only construct a ``tzfile`` directly if you have a specific timezone
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file on disk that you want to read into a Python ``tzinfo`` object.
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If you want to get a ``tzfile`` representing a specific IANA zone,
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(e.g. ``'America/New_York'``), you should call
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:func:`dateutil.tz.gettz` with the zone identifier.
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**Examples:**
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Using the US Eastern time zone as an example, we can see that a ``tzfile``
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provides time zone information for the standard Daylight Saving offsets:
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.. testsetup:: tzfile
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from dateutil.tz import gettz
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from datetime import datetime
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.. doctest:: tzfile
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>>> NYC = gettz('America/New_York')
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>>> NYC
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tzfile('/usr/share/zoneinfo/America/New_York')
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>>> print(datetime(2016, 1, 3, tzinfo=NYC)) # EST
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2016-01-03 00:00:00-05:00
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>>> print(datetime(2016, 7, 7, tzinfo=NYC)) # EDT
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2016-07-07 00:00:00-04:00
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The ``tzfile`` structure contains a fully history of the time zone,
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so historical dates will also have the right offsets. For example, before
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the adoption of the UTC standards, New York used local solar mean time:
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.. doctest:: tzfile
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>>> print(datetime(1901, 4, 12, tzinfo=NYC)) # LMT
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1901-04-12 00:00:00-04:56
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And during World War II, New York was on "Eastern War Time", which was a
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state of permanent daylight saving time:
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.. doctest:: tzfile
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>>> print(datetime(1944, 2, 7, tzinfo=NYC)) # EWT
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1944-02-07 00:00:00-04:00
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"""
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def __init__(self, fileobj, filename=None):
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super(tzfile, self).__init__()
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file_opened_here = False
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if isinstance(fileobj, string_types):
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self._filename = fileobj
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fileobj = open(fileobj, 'rb')
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file_opened_here = True
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elif filename is not None:
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self._filename = filename
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elif hasattr(fileobj, "name"):
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self._filename = fileobj.name
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else:
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self._filename = repr(fileobj)
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if fileobj is not None:
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if not file_opened_here:
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fileobj = _nullcontext(fileobj)
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with fileobj as file_stream:
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tzobj = self._read_tzfile(file_stream)
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self._set_tzdata(tzobj)
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def _set_tzdata(self, tzobj):
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""" Set the time zone data of this object from a _tzfile object """
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# Copy the relevant attributes over as private attributes
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for attr in _tzfile.attrs:
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setattr(self, '_' + attr, getattr(tzobj, attr))
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def _read_tzfile(self, fileobj):
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out = _tzfile()
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# From tzfile(5):
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#
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# The time zone information files used by tzset(3)
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# begin with the magic characters "TZif" to identify
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# them as time zone information files, followed by
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# sixteen bytes reserved for future use, followed by
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# six four-byte values of type long, written in a
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# ``standard'' byte order (the high-order byte
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# of the value is written first).
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if fileobj.read(4).decode() != "TZif":
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raise ValueError("magic not found")
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fileobj.read(16)
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(
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# The number of UTC/local indicators stored in the file.
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ttisgmtcnt,
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# The number of standard/wall indicators stored in the file.
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ttisstdcnt,
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# The number of leap seconds for which data is
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# stored in the file.
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leapcnt,
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# The number of "transition times" for which data
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# is stored in the file.
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timecnt,
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# The number of "local time types" for which data
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# is stored in the file (must not be zero).
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typecnt,
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# The number of characters of "time zone
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# abbreviation strings" stored in the file.
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charcnt,
|
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) = struct.unpack(">6l", fileobj.read(24))
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# The above header is followed by tzh_timecnt four-byte
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# values of type long, sorted in ascending order.
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# These values are written in ``standard'' byte order.
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# Each is used as a transition time (as returned by
|
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# time(2)) at which the rules for computing local time
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# change.
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|
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if timecnt:
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out.trans_list_utc = list(struct.unpack(">%dl" % timecnt,
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fileobj.read(timecnt*4)))
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else:
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out.trans_list_utc = []
|
|
|
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# Next come tzh_timecnt one-byte values of type unsigned
|
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# char; each one tells which of the different types of
|
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# ``local time'' types described in the file is associated
|
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# with the same-indexed transition time. These values
|
|
# serve as indices into an array of ttinfo structures that
|
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# appears next in the file.
|
|
|
|
if timecnt:
|
|
out.trans_idx = struct.unpack(">%dB" % timecnt,
|
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fileobj.read(timecnt))
|
|
else:
|
|
out.trans_idx = []
|
|
|
|
# Each ttinfo structure is written as a four-byte value
|
|
# for tt_gmtoff of type long, in a standard byte
|
|
# order, followed by a one-byte value for tt_isdst
|
|
# and a one-byte value for tt_abbrind. In each
|
|
# structure, tt_gmtoff gives the number of
|
|
# seconds to be added to UTC, tt_isdst tells whether
|
|
# tm_isdst should be set by localtime(3), and
|
|
# tt_abbrind serves as an index into the array of
|
|
# time zone abbreviation characters that follow the
|
|
# ttinfo structure(s) in the file.
|
|
|
|
ttinfo = []
|
|
|
|
for i in range(typecnt):
|
|
ttinfo.append(struct.unpack(">lbb", fileobj.read(6)))
|
|
|
|
abbr = fileobj.read(charcnt).decode()
|
|
|
|
# Then there are tzh_leapcnt pairs of four-byte
|
|
# values, written in standard byte order; the
|
|
# first value of each pair gives the time (as
|
|
# returned by time(2)) at which a leap second
|
|
# occurs; the second gives the total number of
|
|
# leap seconds to be applied after the given time.
|
|
# The pairs of values are sorted in ascending order
|
|
# by time.
|
|
|
|
# Not used, for now (but seek for correct file position)
|
|
if leapcnt:
|
|
fileobj.seek(leapcnt * 8, os.SEEK_CUR)
|
|
|
|
# Then there are tzh_ttisstdcnt standard/wall
|
|
# indicators, each stored as a one-byte value;
|
|
# they tell whether the transition times associated
|
|
# with local time types were specified as standard
|
|
# time or wall clock time, and are used when
|
|
# a time zone file is used in handling POSIX-style
|
|
# time zone environment variables.
|
|
|
|
if ttisstdcnt:
|
|
isstd = struct.unpack(">%db" % ttisstdcnt,
|
|
fileobj.read(ttisstdcnt))
|
|
|
|
# Finally, there are tzh_ttisgmtcnt UTC/local
|
|
# indicators, each stored as a one-byte value;
|
|
# they tell whether the transition times associated
|
|
# with local time types were specified as UTC or
|
|
# local time, and are used when a time zone file
|
|
# is used in handling POSIX-style time zone envi-
|
|
# ronment variables.
|
|
|
|
if ttisgmtcnt:
|
|
isgmt = struct.unpack(">%db" % ttisgmtcnt,
|
|
fileobj.read(ttisgmtcnt))
|
|
|
|
# Build ttinfo list
|
|
out.ttinfo_list = []
|
|
for i in range(typecnt):
|
|
gmtoff, isdst, abbrind = ttinfo[i]
|
|
gmtoff = _get_supported_offset(gmtoff)
|
|
tti = _ttinfo()
|
|
tti.offset = gmtoff
|
|
tti.dstoffset = datetime.timedelta(0)
|
|
tti.delta = datetime.timedelta(seconds=gmtoff)
|
|
tti.isdst = isdst
|
|
tti.abbr = abbr[abbrind:abbr.find('\x00', abbrind)]
|
|
tti.isstd = (ttisstdcnt > i and isstd[i] != 0)
|
|
tti.isgmt = (ttisgmtcnt > i and isgmt[i] != 0)
|
|
out.ttinfo_list.append(tti)
|
|
|
|
# Replace ttinfo indexes for ttinfo objects.
|
|
out.trans_idx = [out.ttinfo_list[idx] for idx in out.trans_idx]
|
|
|
|
# Set standard, dst, and before ttinfos. before will be
|
|
# used when a given time is before any transitions,
|
|
# and will be set to the first non-dst ttinfo, or to
|
|
# the first dst, if all of them are dst.
|
|
out.ttinfo_std = None
|
|
out.ttinfo_dst = None
|
|
out.ttinfo_before = None
|
|
if out.ttinfo_list:
|
|
if not out.trans_list_utc:
|
|
out.ttinfo_std = out.ttinfo_first = out.ttinfo_list[0]
|
|
else:
|
|
for i in range(timecnt-1, -1, -1):
|
|
tti = out.trans_idx[i]
|
|
if not out.ttinfo_std and not tti.isdst:
|
|
out.ttinfo_std = tti
|
|
elif not out.ttinfo_dst and tti.isdst:
|
|
out.ttinfo_dst = tti
|
|
|
|
if out.ttinfo_std and out.ttinfo_dst:
|
|
break
|
|
else:
|
|
if out.ttinfo_dst and not out.ttinfo_std:
|
|
out.ttinfo_std = out.ttinfo_dst
|
|
|
|
for tti in out.ttinfo_list:
|
|
if not tti.isdst:
|
|
out.ttinfo_before = tti
|
|
break
|
|
else:
|
|
out.ttinfo_before = out.ttinfo_list[0]
|
|
|
|
# Now fix transition times to become relative to wall time.
|
|
#
|
|
# I'm not sure about this. In my tests, the tz source file
|
|
# is setup to wall time, and in the binary file isstd and
|
|
# isgmt are off, so it should be in wall time. OTOH, it's
|
|
# always in gmt time. Let me know if you have comments
|
|
# about this.
|
|
lastdst = None
|
|
lastoffset = None
|
|
lastdstoffset = None
|
|
lastbaseoffset = None
|
|
out.trans_list = []
|
|
|
|
for i, tti in enumerate(out.trans_idx):
|
|
offset = tti.offset
|
|
dstoffset = 0
|
|
|
|
if lastdst is not None:
|
|
if tti.isdst:
|
|
if not lastdst:
|
|
dstoffset = offset - lastoffset
|
|
|
|
if not dstoffset and lastdstoffset:
|
|
dstoffset = lastdstoffset
|
|
|
|
tti.dstoffset = datetime.timedelta(seconds=dstoffset)
|
|
lastdstoffset = dstoffset
|
|
|
|
# If a time zone changes its base offset during a DST transition,
|
|
# then you need to adjust by the previous base offset to get the
|
|
# transition time in local time. Otherwise you use the current
|
|
# base offset. Ideally, I would have some mathematical proof of
|
|
# why this is true, but I haven't really thought about it enough.
|
|
baseoffset = offset - dstoffset
|
|
adjustment = baseoffset
|
|
if (lastbaseoffset is not None and baseoffset != lastbaseoffset
|
|
and tti.isdst != lastdst):
|
|
# The base DST has changed
|
|
adjustment = lastbaseoffset
|
|
|
|
lastdst = tti.isdst
|
|
lastoffset = offset
|
|
lastbaseoffset = baseoffset
|
|
|
|
out.trans_list.append(out.trans_list_utc[i] + adjustment)
|
|
|
|
out.trans_idx = tuple(out.trans_idx)
|
|
out.trans_list = tuple(out.trans_list)
|
|
out.trans_list_utc = tuple(out.trans_list_utc)
|
|
|
|
return out
|
|
|
|
def _find_last_transition(self, dt, in_utc=False):
|
|
# If there's no list, there are no transitions to find
|
|
if not self._trans_list:
|
|
return None
|
|
|
|
timestamp = _datetime_to_timestamp(dt)
|
|
|
|
# Find where the timestamp fits in the transition list - if the
|
|
# timestamp is a transition time, it's part of the "after" period.
|
|
trans_list = self._trans_list_utc if in_utc else self._trans_list
|
|
idx = bisect.bisect_right(trans_list, timestamp)
|
|
|
|
# We want to know when the previous transition was, so subtract off 1
|
|
return idx - 1
|
|
|
|
def _get_ttinfo(self, idx):
|
|
# For no list or after the last transition, default to _ttinfo_std
|
|
if idx is None or (idx + 1) >= len(self._trans_list):
|
|
return self._ttinfo_std
|
|
|
|
# If there is a list and the time is before it, return _ttinfo_before
|
|
if idx < 0:
|
|
return self._ttinfo_before
|
|
|
|
return self._trans_idx[idx]
|
|
|
|
def _find_ttinfo(self, dt):
|
|
idx = self._resolve_ambiguous_time(dt)
|
|
|
|
return self._get_ttinfo(idx)
|
|
|
|
def fromutc(self, dt):
|
|
"""
|
|
The ``tzfile`` implementation of :py:func:`datetime.tzinfo.fromutc`.
|
|
|
|
:param dt:
|
|
A :py:class:`datetime.datetime` object.
|
|
|
|
:raises TypeError:
|
|
Raised if ``dt`` is not a :py:class:`datetime.datetime` object.
|
|
|
|
:raises ValueError:
|
|
Raised if this is called with a ``dt`` which does not have this
|
|
``tzinfo`` attached.
|
|
|
|
:return:
|
|
Returns a :py:class:`datetime.datetime` object representing the
|
|
wall time in ``self``'s time zone.
|
|
"""
|
|
# These isinstance checks are in datetime.tzinfo, so we'll preserve
|
|
# them, even if we don't care about duck typing.
|
|
if not isinstance(dt, datetime.datetime):
|
|
raise TypeError("fromutc() requires a datetime argument")
|
|
|
|
if dt.tzinfo is not self:
|
|
raise ValueError("dt.tzinfo is not self")
|
|
|
|
# First treat UTC as wall time and get the transition we're in.
|
|
idx = self._find_last_transition(dt, in_utc=True)
|
|
tti = self._get_ttinfo(idx)
|
|
|
|
dt_out = dt + datetime.timedelta(seconds=tti.offset)
|
|
|
|
fold = self.is_ambiguous(dt_out, idx=idx)
|
|
|
|
return enfold(dt_out, fold=int(fold))
|
|
|
|
def is_ambiguous(self, dt, idx=None):
|
|
"""
|
|
Whether or not the "wall time" of a given datetime is ambiguous in this
|
|
zone.
|
|
|
|
:param dt:
|
|
A :py:class:`datetime.datetime`, naive or time zone aware.
|
|
|
|
|
|
:return:
|
|
Returns ``True`` if ambiguous, ``False`` otherwise.
|
|
|
|
.. versionadded:: 2.6.0
|
|
"""
|
|
if idx is None:
|
|
idx = self._find_last_transition(dt)
|
|
|
|
# Calculate the difference in offsets from current to previous
|
|
timestamp = _datetime_to_timestamp(dt)
|
|
tti = self._get_ttinfo(idx)
|
|
|
|
if idx is None or idx <= 0:
|
|
return False
|
|
|
|
od = self._get_ttinfo(idx - 1).offset - tti.offset
|
|
tt = self._trans_list[idx] # Transition time
|
|
|
|
return timestamp < tt + od
|
|
|
|
def _resolve_ambiguous_time(self, dt):
|
|
idx = self._find_last_transition(dt)
|
|
|
|
# If we have no transitions, return the index
|
|
_fold = self._fold(dt)
|
|
if idx is None or idx == 0:
|
|
return idx
|
|
|
|
# If it's ambiguous and we're in a fold, shift to a different index.
|
|
idx_offset = int(not _fold and self.is_ambiguous(dt, idx))
|
|
|
|
return idx - idx_offset
|
|
|
|
def utcoffset(self, dt):
|
|
if dt is None:
|
|
return None
|
|
|
|
if not self._ttinfo_std:
|
|
return ZERO
|
|
|
|
return self._find_ttinfo(dt).delta
|
|
|
|
def dst(self, dt):
|
|
if dt is None:
|
|
return None
|
|
|
|
if not self._ttinfo_dst:
|
|
return ZERO
|
|
|
|
tti = self._find_ttinfo(dt)
|
|
|
|
if not tti.isdst:
|
|
return ZERO
|
|
|
|
# The documentation says that utcoffset()-dst() must
|
|
# be constant for every dt.
|
|
return tti.dstoffset
|
|
|
|
@tzname_in_python2
|
|
def tzname(self, dt):
|
|
if not self._ttinfo_std or dt is None:
|
|
return None
|
|
return self._find_ttinfo(dt).abbr
|
|
|
|
def __eq__(self, other):
|
|
if not isinstance(other, tzfile):
|
|
return NotImplemented
|
|
return (self._trans_list == other._trans_list and
|
|
self._trans_idx == other._trans_idx and
|
|
self._ttinfo_list == other._ttinfo_list)
|
|
|
|
__hash__ = None
|
|
|
|
def __ne__(self, other):
|
|
return not (self == other)
|
|
|
|
def __repr__(self):
|
|
return "%s(%s)" % (self.__class__.__name__, repr(self._filename))
|
|
|
|
def __reduce__(self):
|
|
return self.__reduce_ex__(None)
|
|
|
|
def __reduce_ex__(self, protocol):
|
|
return (self.__class__, (None, self._filename), self.__dict__)
|
|
|
|
|
|
class tzrange(tzrangebase):
|
|
"""
|
|
The ``tzrange`` object is a time zone specified by a set of offsets and
|
|
abbreviations, equivalent to the way the ``TZ`` variable can be specified
|
|
in POSIX-like systems, but using Python delta objects to specify DST
|
|
start, end and offsets.
|
|
|
|
:param stdabbr:
|
|
The abbreviation for standard time (e.g. ``'EST'``).
|
|
|
|
:param stdoffset:
|
|
An integer or :class:`datetime.timedelta` object or equivalent
|
|
specifying the base offset from UTC.
|
|
|
|
If unspecified, +00:00 is used.
|
|
|
|
:param dstabbr:
|
|
The abbreviation for DST / "Summer" time (e.g. ``'EDT'``).
|
|
|
|
If specified, with no other DST information, DST is assumed to occur
|
|
and the default behavior or ``dstoffset``, ``start`` and ``end`` is
|
|
used. If unspecified and no other DST information is specified, it
|
|
is assumed that this zone has no DST.
|
|
|
|
If this is unspecified and other DST information is *is* specified,
|
|
DST occurs in the zone but the time zone abbreviation is left
|
|
unchanged.
|
|
|
|
:param dstoffset:
|
|
A an integer or :class:`datetime.timedelta` object or equivalent
|
|
specifying the UTC offset during DST. If unspecified and any other DST
|
|
information is specified, it is assumed to be the STD offset +1 hour.
|
|
|
|
:param start:
|
|
A :class:`relativedelta.relativedelta` object or equivalent specifying
|
|
the time and time of year that daylight savings time starts. To
|
|
specify, for example, that DST starts at 2AM on the 2nd Sunday in
|
|
March, pass:
|
|
|
|
``relativedelta(hours=2, month=3, day=1, weekday=SU(+2))``
|
|
|
|
If unspecified and any other DST information is specified, the default
|
|
value is 2 AM on the first Sunday in April.
|
|
|
|
:param end:
|
|
A :class:`relativedelta.relativedelta` object or equivalent
|
|
representing the time and time of year that daylight savings time
|
|
ends, with the same specification method as in ``start``. One note is
|
|
that this should point to the first time in the *standard* zone, so if
|
|
a transition occurs at 2AM in the DST zone and the clocks are set back
|
|
1 hour to 1AM, set the ``hours`` parameter to +1.
|
|
|
|
|
|
**Examples:**
|
|
|
|
.. testsetup:: tzrange
|
|
|
|
from dateutil.tz import tzrange, tzstr
|
|
|
|
.. doctest:: tzrange
|
|
|
|
>>> tzstr('EST5EDT') == tzrange("EST", -18000, "EDT")
|
|
True
|
|
|
|
>>> from dateutil.relativedelta import *
|
|
>>> range1 = tzrange("EST", -18000, "EDT")
|
|
>>> range2 = tzrange("EST", -18000, "EDT", -14400,
|
|
... relativedelta(hours=+2, month=4, day=1,
|
|
... weekday=SU(+1)),
|
|
... relativedelta(hours=+1, month=10, day=31,
|
|
... weekday=SU(-1)))
|
|
>>> tzstr('EST5EDT') == range1 == range2
|
|
True
|
|
|
|
"""
|
|
def __init__(self, stdabbr, stdoffset=None,
|
|
dstabbr=None, dstoffset=None,
|
|
start=None, end=None):
|
|
|
|
global relativedelta
|
|
from dateutil import relativedelta
|
|
|
|
self._std_abbr = stdabbr
|
|
self._dst_abbr = dstabbr
|
|
|
|
try:
|
|
stdoffset = stdoffset.total_seconds()
|
|
except (TypeError, AttributeError):
|
|
pass
|
|
|
|
try:
|
|
dstoffset = dstoffset.total_seconds()
|
|
except (TypeError, AttributeError):
|
|
pass
|
|
|
|
if stdoffset is not None:
|
|
self._std_offset = datetime.timedelta(seconds=stdoffset)
|
|
else:
|
|
self._std_offset = ZERO
|
|
|
|
if dstoffset is not None:
|
|
self._dst_offset = datetime.timedelta(seconds=dstoffset)
|
|
elif dstabbr and stdoffset is not None:
|
|
self._dst_offset = self._std_offset + datetime.timedelta(hours=+1)
|
|
else:
|
|
self._dst_offset = ZERO
|
|
|
|
if dstabbr and start is None:
|
|
self._start_delta = relativedelta.relativedelta(
|
|
hours=+2, month=4, day=1, weekday=relativedelta.SU(+1))
|
|
else:
|
|
self._start_delta = start
|
|
|
|
if dstabbr and end is None:
|
|
self._end_delta = relativedelta.relativedelta(
|
|
hours=+1, month=10, day=31, weekday=relativedelta.SU(-1))
|
|
else:
|
|
self._end_delta = end
|
|
|
|
self._dst_base_offset_ = self._dst_offset - self._std_offset
|
|
self.hasdst = bool(self._start_delta)
|
|
|
|
def transitions(self, year):
|
|
"""
|
|
For a given year, get the DST on and off transition times, expressed
|
|
always on the standard time side. For zones with no transitions, this
|
|
function returns ``None``.
|
|
|
|
:param year:
|
|
The year whose transitions you would like to query.
|
|
|
|
:return:
|
|
Returns a :class:`tuple` of :class:`datetime.datetime` objects,
|
|
``(dston, dstoff)`` for zones with an annual DST transition, or
|
|
``None`` for fixed offset zones.
|
|
"""
|
|
if not self.hasdst:
|
|
return None
|
|
|
|
base_year = datetime.datetime(year, 1, 1)
|
|
|
|
start = base_year + self._start_delta
|
|
end = base_year + self._end_delta
|
|
|
|
return (start, end)
|
|
|
|
def __eq__(self, other):
|
|
if not isinstance(other, tzrange):
|
|
return NotImplemented
|
|
|
|
return (self._std_abbr == other._std_abbr and
|
|
self._dst_abbr == other._dst_abbr and
|
|
self._std_offset == other._std_offset and
|
|
self._dst_offset == other._dst_offset and
|
|
self._start_delta == other._start_delta and
|
|
self._end_delta == other._end_delta)
|
|
|
|
@property
|
|
def _dst_base_offset(self):
|
|
return self._dst_base_offset_
|
|
|
|
|
|
@six.add_metaclass(_TzStrFactory)
|
|
class tzstr(tzrange):
|
|
"""
|
|
``tzstr`` objects are time zone objects specified by a time-zone string as
|
|
it would be passed to a ``TZ`` variable on POSIX-style systems (see
|
|
the `GNU C Library: TZ Variable`_ for more details).
|
|
|
|
There is one notable exception, which is that POSIX-style time zones use an
|
|
inverted offset format, so normally ``GMT+3`` would be parsed as an offset
|
|
3 hours *behind* GMT. The ``tzstr`` time zone object will parse this as an
|
|
offset 3 hours *ahead* of GMT. If you would like to maintain the POSIX
|
|
behavior, pass a ``True`` value to ``posix_offset``.
|
|
|
|
The :class:`tzrange` object provides the same functionality, but is
|
|
specified using :class:`relativedelta.relativedelta` objects. rather than
|
|
strings.
|
|
|
|
:param s:
|
|
A time zone string in ``TZ`` variable format. This can be a
|
|
:class:`bytes` (2.x: :class:`str`), :class:`str` (2.x:
|
|
:class:`unicode`) or a stream emitting unicode characters
|
|
(e.g. :class:`StringIO`).
|
|
|
|
:param posix_offset:
|
|
Optional. If set to ``True``, interpret strings such as ``GMT+3`` or
|
|
``UTC+3`` as being 3 hours *behind* UTC rather than ahead, per the
|
|
POSIX standard.
|
|
|
|
.. caution::
|
|
|
|
Prior to version 2.7.0, this function also supported time zones
|
|
in the format:
|
|
|
|
* ``EST5EDT,4,0,6,7200,10,0,26,7200,3600``
|
|
* ``EST5EDT,4,1,0,7200,10,-1,0,7200,3600``
|
|
|
|
This format is non-standard and has been deprecated; this function
|
|
will raise a :class:`DeprecatedTZFormatWarning` until
|
|
support is removed in a future version.
|
|
|
|
.. _`GNU C Library: TZ Variable`:
|
|
https://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html
|
|
"""
|
|
def __init__(self, s, posix_offset=False):
|
|
global parser
|
|
from dateutil.parser import _parser as parser
|
|
|
|
self._s = s
|
|
|
|
res = parser._parsetz(s)
|
|
if res is None or res.any_unused_tokens:
|
|
raise ValueError("unknown string format")
|
|
|
|
# Here we break the compatibility with the TZ variable handling.
|
|
# GMT-3 actually *means* the timezone -3.
|
|
if res.stdabbr in ("GMT", "UTC") and not posix_offset:
|
|
res.stdoffset *= -1
|
|
|
|
# We must initialize it first, since _delta() needs
|
|
# _std_offset and _dst_offset set. Use False in start/end
|
|
# to avoid building it two times.
|
|
tzrange.__init__(self, res.stdabbr, res.stdoffset,
|
|
res.dstabbr, res.dstoffset,
|
|
start=False, end=False)
|
|
|
|
if not res.dstabbr:
|
|
self._start_delta = None
|
|
self._end_delta = None
|
|
else:
|
|
self._start_delta = self._delta(res.start)
|
|
if self._start_delta:
|
|
self._end_delta = self._delta(res.end, isend=1)
|
|
|
|
self.hasdst = bool(self._start_delta)
|
|
|
|
def _delta(self, x, isend=0):
|
|
from dateutil import relativedelta
|
|
kwargs = {}
|
|
if x.month is not None:
|
|
kwargs["month"] = x.month
|
|
if x.weekday is not None:
|
|
kwargs["weekday"] = relativedelta.weekday(x.weekday, x.week)
|
|
if x.week > 0:
|
|
kwargs["day"] = 1
|
|
else:
|
|
kwargs["day"] = 31
|
|
elif x.day:
|
|
kwargs["day"] = x.day
|
|
elif x.yday is not None:
|
|
kwargs["yearday"] = x.yday
|
|
elif x.jyday is not None:
|
|
kwargs["nlyearday"] = x.jyday
|
|
if not kwargs:
|
|
# Default is to start on first sunday of april, and end
|
|
# on last sunday of october.
|
|
if not isend:
|
|
kwargs["month"] = 4
|
|
kwargs["day"] = 1
|
|
kwargs["weekday"] = relativedelta.SU(+1)
|
|
else:
|
|
kwargs["month"] = 10
|
|
kwargs["day"] = 31
|
|
kwargs["weekday"] = relativedelta.SU(-1)
|
|
if x.time is not None:
|
|
kwargs["seconds"] = x.time
|
|
else:
|
|
# Default is 2AM.
|
|
kwargs["seconds"] = 7200
|
|
if isend:
|
|
# Convert to standard time, to follow the documented way
|
|
# of working with the extra hour. See the documentation
|
|
# of the tzinfo class.
|
|
delta = self._dst_offset - self._std_offset
|
|
kwargs["seconds"] -= delta.seconds + delta.days * 86400
|
|
return relativedelta.relativedelta(**kwargs)
|
|
|
|
def __repr__(self):
|
|
return "%s(%s)" % (self.__class__.__name__, repr(self._s))
|
|
|
|
|
|
class _tzicalvtzcomp(object):
|
|
def __init__(self, tzoffsetfrom, tzoffsetto, isdst,
|
|
tzname=None, rrule=None):
|
|
self.tzoffsetfrom = datetime.timedelta(seconds=tzoffsetfrom)
|
|
self.tzoffsetto = datetime.timedelta(seconds=tzoffsetto)
|
|
self.tzoffsetdiff = self.tzoffsetto - self.tzoffsetfrom
|
|
self.isdst = isdst
|
|
self.tzname = tzname
|
|
self.rrule = rrule
|
|
|
|
|
|
class _tzicalvtz(_tzinfo):
|
|
def __init__(self, tzid, comps=[]):
|
|
super(_tzicalvtz, self).__init__()
|
|
|
|
self._tzid = tzid
|
|
self._comps = comps
|
|
self._cachedate = []
|
|
self._cachecomp = []
|
|
self._cache_lock = _thread.allocate_lock()
|
|
|
|
def _find_comp(self, dt):
|
|
if len(self._comps) == 1:
|
|
return self._comps[0]
|
|
|
|
dt = dt.replace(tzinfo=None)
|
|
|
|
try:
|
|
with self._cache_lock:
|
|
return self._cachecomp[self._cachedate.index(
|
|
(dt, self._fold(dt)))]
|
|
except ValueError:
|
|
pass
|
|
|
|
lastcompdt = None
|
|
lastcomp = None
|
|
|
|
for comp in self._comps:
|
|
compdt = self._find_compdt(comp, dt)
|
|
|
|
if compdt and (not lastcompdt or lastcompdt < compdt):
|
|
lastcompdt = compdt
|
|
lastcomp = comp
|
|
|
|
if not lastcomp:
|
|
# RFC says nothing about what to do when a given
|
|
# time is before the first onset date. We'll look for the
|
|
# first standard component, or the first component, if
|
|
# none is found.
|
|
for comp in self._comps:
|
|
if not comp.isdst:
|
|
lastcomp = comp
|
|
break
|
|
else:
|
|
lastcomp = comp[0]
|
|
|
|
with self._cache_lock:
|
|
self._cachedate.insert(0, (dt, self._fold(dt)))
|
|
self._cachecomp.insert(0, lastcomp)
|
|
|
|
if len(self._cachedate) > 10:
|
|
self._cachedate.pop()
|
|
self._cachecomp.pop()
|
|
|
|
return lastcomp
|
|
|
|
def _find_compdt(self, comp, dt):
|
|
if comp.tzoffsetdiff < ZERO and self._fold(dt):
|
|
dt -= comp.tzoffsetdiff
|
|
|
|
compdt = comp.rrule.before(dt, inc=True)
|
|
|
|
return compdt
|
|
|
|
def utcoffset(self, dt):
|
|
if dt is None:
|
|
return None
|
|
|
|
return self._find_comp(dt).tzoffsetto
|
|
|
|
def dst(self, dt):
|
|
comp = self._find_comp(dt)
|
|
if comp.isdst:
|
|
return comp.tzoffsetdiff
|
|
else:
|
|
return ZERO
|
|
|
|
@tzname_in_python2
|
|
def tzname(self, dt):
|
|
return self._find_comp(dt).tzname
|
|
|
|
def __repr__(self):
|
|
return "<tzicalvtz %s>" % repr(self._tzid)
|
|
|
|
__reduce__ = object.__reduce__
|
|
|
|
|
|
class tzical(object):
|
|
"""
|
|
This object is designed to parse an iCalendar-style ``VTIMEZONE`` structure
|
|
as set out in `RFC 5545`_ Section 4.6.5 into one or more `tzinfo` objects.
|
|
|
|
:param `fileobj`:
|
|
A file or stream in iCalendar format, which should be UTF-8 encoded
|
|
with CRLF endings.
|
|
|
|
.. _`RFC 5545`: https://tools.ietf.org/html/rfc5545
|
|
"""
|
|
def __init__(self, fileobj):
|
|
global rrule
|
|
from dateutil import rrule
|
|
|
|
if isinstance(fileobj, string_types):
|
|
self._s = fileobj
|
|
# ical should be encoded in UTF-8 with CRLF
|
|
fileobj = open(fileobj, 'r')
|
|
else:
|
|
self._s = getattr(fileobj, 'name', repr(fileobj))
|
|
fileobj = _nullcontext(fileobj)
|
|
|
|
self._vtz = {}
|
|
|
|
with fileobj as fobj:
|
|
self._parse_rfc(fobj.read())
|
|
|
|
def keys(self):
|
|
"""
|
|
Retrieves the available time zones as a list.
|
|
"""
|
|
return list(self._vtz.keys())
|
|
|
|
def get(self, tzid=None):
|
|
"""
|
|
Retrieve a :py:class:`datetime.tzinfo` object by its ``tzid``.
|
|
|
|
:param tzid:
|
|
If there is exactly one time zone available, omitting ``tzid``
|
|
or passing :py:const:`None` value returns it. Otherwise a valid
|
|
key (which can be retrieved from :func:`keys`) is required.
|
|
|
|
:raises ValueError:
|
|
Raised if ``tzid`` is not specified but there are either more
|
|
or fewer than 1 zone defined.
|
|
|
|
:returns:
|
|
Returns either a :py:class:`datetime.tzinfo` object representing
|
|
the relevant time zone or :py:const:`None` if the ``tzid`` was
|
|
not found.
|
|
"""
|
|
if tzid is None:
|
|
if len(self._vtz) == 0:
|
|
raise ValueError("no timezones defined")
|
|
elif len(self._vtz) > 1:
|
|
raise ValueError("more than one timezone available")
|
|
tzid = next(iter(self._vtz))
|
|
|
|
return self._vtz.get(tzid)
|
|
|
|
def _parse_offset(self, s):
|
|
s = s.strip()
|
|
if not s:
|
|
raise ValueError("empty offset")
|
|
if s[0] in ('+', '-'):
|
|
signal = (-1, +1)[s[0] == '+']
|
|
s = s[1:]
|
|
else:
|
|
signal = +1
|
|
if len(s) == 4:
|
|
return (int(s[:2]) * 3600 + int(s[2:]) * 60) * signal
|
|
elif len(s) == 6:
|
|
return (int(s[:2]) * 3600 + int(s[2:4]) * 60 + int(s[4:])) * signal
|
|
else:
|
|
raise ValueError("invalid offset: " + s)
|
|
|
|
def _parse_rfc(self, s):
|
|
lines = s.splitlines()
|
|
if not lines:
|
|
raise ValueError("empty string")
|
|
|
|
# Unfold
|
|
i = 0
|
|
while i < len(lines):
|
|
line = lines[i].rstrip()
|
|
if not line:
|
|
del lines[i]
|
|
elif i > 0 and line[0] == " ":
|
|
lines[i-1] += line[1:]
|
|
del lines[i]
|
|
else:
|
|
i += 1
|
|
|
|
tzid = None
|
|
comps = []
|
|
invtz = False
|
|
comptype = None
|
|
for line in lines:
|
|
if not line:
|
|
continue
|
|
name, value = line.split(':', 1)
|
|
parms = name.split(';')
|
|
if not parms:
|
|
raise ValueError("empty property name")
|
|
name = parms[0].upper()
|
|
parms = parms[1:]
|
|
if invtz:
|
|
if name == "BEGIN":
|
|
if value in ("STANDARD", "DAYLIGHT"):
|
|
# Process component
|
|
pass
|
|
else:
|
|
raise ValueError("unknown component: "+value)
|
|
comptype = value
|
|
founddtstart = False
|
|
tzoffsetfrom = None
|
|
tzoffsetto = None
|
|
rrulelines = []
|
|
tzname = None
|
|
elif name == "END":
|
|
if value == "VTIMEZONE":
|
|
if comptype:
|
|
raise ValueError("component not closed: "+comptype)
|
|
if not tzid:
|
|
raise ValueError("mandatory TZID not found")
|
|
if not comps:
|
|
raise ValueError(
|
|
"at least one component is needed")
|
|
# Process vtimezone
|
|
self._vtz[tzid] = _tzicalvtz(tzid, comps)
|
|
invtz = False
|
|
elif value == comptype:
|
|
if not founddtstart:
|
|
raise ValueError("mandatory DTSTART not found")
|
|
if tzoffsetfrom is None:
|
|
raise ValueError(
|
|
"mandatory TZOFFSETFROM not found")
|
|
if tzoffsetto is None:
|
|
raise ValueError(
|
|
"mandatory TZOFFSETFROM not found")
|
|
# Process component
|
|
rr = None
|
|
if rrulelines:
|
|
rr = rrule.rrulestr("\n".join(rrulelines),
|
|
compatible=True,
|
|
ignoretz=True,
|
|
cache=True)
|
|
comp = _tzicalvtzcomp(tzoffsetfrom, tzoffsetto,
|
|
(comptype == "DAYLIGHT"),
|
|
tzname, rr)
|
|
comps.append(comp)
|
|
comptype = None
|
|
else:
|
|
raise ValueError("invalid component end: "+value)
|
|
elif comptype:
|
|
if name == "DTSTART":
|
|
# DTSTART in VTIMEZONE takes a subset of valid RRULE
|
|
# values under RFC 5545.
|
|
for parm in parms:
|
|
if parm != 'VALUE=DATE-TIME':
|
|
msg = ('Unsupported DTSTART param in ' +
|
|
'VTIMEZONE: ' + parm)
|
|
raise ValueError(msg)
|
|
rrulelines.append(line)
|
|
founddtstart = True
|
|
elif name in ("RRULE", "RDATE", "EXRULE", "EXDATE"):
|
|
rrulelines.append(line)
|
|
elif name == "TZOFFSETFROM":
|
|
if parms:
|
|
raise ValueError(
|
|
"unsupported %s parm: %s " % (name, parms[0]))
|
|
tzoffsetfrom = self._parse_offset(value)
|
|
elif name == "TZOFFSETTO":
|
|
if parms:
|
|
raise ValueError(
|
|
"unsupported TZOFFSETTO parm: "+parms[0])
|
|
tzoffsetto = self._parse_offset(value)
|
|
elif name == "TZNAME":
|
|
if parms:
|
|
raise ValueError(
|
|
"unsupported TZNAME parm: "+parms[0])
|
|
tzname = value
|
|
elif name == "COMMENT":
|
|
pass
|
|
else:
|
|
raise ValueError("unsupported property: "+name)
|
|
else:
|
|
if name == "TZID":
|
|
if parms:
|
|
raise ValueError(
|
|
"unsupported TZID parm: "+parms[0])
|
|
tzid = value
|
|
elif name in ("TZURL", "LAST-MODIFIED", "COMMENT"):
|
|
pass
|
|
else:
|
|
raise ValueError("unsupported property: "+name)
|
|
elif name == "BEGIN" and value == "VTIMEZONE":
|
|
tzid = None
|
|
comps = []
|
|
invtz = True
|
|
|
|
def __repr__(self):
|
|
return "%s(%s)" % (self.__class__.__name__, repr(self._s))
|
|
|
|
|
|
if sys.platform != "win32":
|
|
TZFILES = ["/etc/localtime", "localtime"]
|
|
TZPATHS = ["/usr/share/zoneinfo",
|
|
"/usr/lib/zoneinfo",
|
|
"/usr/share/lib/zoneinfo",
|
|
"/etc/zoneinfo"]
|
|
else:
|
|
TZFILES = []
|
|
TZPATHS = []
|
|
|
|
|
|
def __get_gettz():
|
|
tzlocal_classes = (tzlocal,)
|
|
if tzwinlocal is not None:
|
|
tzlocal_classes += (tzwinlocal,)
|
|
|
|
class GettzFunc(object):
|
|
"""
|
|
Retrieve a time zone object from a string representation
|
|
|
|
This function is intended to retrieve the :py:class:`tzinfo` subclass
|
|
that best represents the time zone that would be used if a POSIX
|
|
`TZ variable`_ were set to the same value.
|
|
|
|
If no argument or an empty string is passed to ``gettz``, local time
|
|
is returned:
|
|
|
|
.. code-block:: python3
|
|
|
|
>>> gettz()
|
|
tzfile('/etc/localtime')
|
|
|
|
This function is also the preferred way to map IANA tz database keys
|
|
to :class:`tzfile` objects:
|
|
|
|
.. code-block:: python3
|
|
|
|
>>> gettz('Pacific/Kiritimati')
|
|
tzfile('/usr/share/zoneinfo/Pacific/Kiritimati')
|
|
|
|
On Windows, the standard is extended to include the Windows-specific
|
|
zone names provided by the operating system:
|
|
|
|
.. code-block:: python3
|
|
|
|
>>> gettz('Egypt Standard Time')
|
|
tzwin('Egypt Standard Time')
|
|
|
|
Passing a GNU ``TZ`` style string time zone specification returns a
|
|
:class:`tzstr` object:
|
|
|
|
.. code-block:: python3
|
|
|
|
>>> gettz('AEST-10AEDT-11,M10.1.0/2,M4.1.0/3')
|
|
tzstr('AEST-10AEDT-11,M10.1.0/2,M4.1.0/3')
|
|
|
|
:param name:
|
|
A time zone name (IANA, or, on Windows, Windows keys), location of
|
|
a ``tzfile(5)`` zoneinfo file or ``TZ`` variable style time zone
|
|
specifier. An empty string, no argument or ``None`` is interpreted
|
|
as local time.
|
|
|
|
:return:
|
|
Returns an instance of one of ``dateutil``'s :py:class:`tzinfo`
|
|
subclasses.
|
|
|
|
.. versionchanged:: 2.7.0
|
|
|
|
After version 2.7.0, any two calls to ``gettz`` using the same
|
|
input strings will return the same object:
|
|
|
|
.. code-block:: python3
|
|
|
|
>>> tz.gettz('America/Chicago') is tz.gettz('America/Chicago')
|
|
True
|
|
|
|
In addition to improving performance, this ensures that
|
|
`"same zone" semantics`_ are used for datetimes in the same zone.
|
|
|
|
|
|
.. _`TZ variable`:
|
|
https://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html
|
|
|
|
.. _`"same zone" semantics`:
|
|
https://blog.ganssle.io/articles/2018/02/aware-datetime-arithmetic.html
|
|
"""
|
|
def __init__(self):
|
|
|
|
self.__instances = weakref.WeakValueDictionary()
|
|
self.__strong_cache_size = 8
|
|
self.__strong_cache = OrderedDict()
|
|
self._cache_lock = _thread.allocate_lock()
|
|
|
|
def __call__(self, name=None):
|
|
with self._cache_lock:
|
|
rv = self.__instances.get(name, None)
|
|
|
|
if rv is None:
|
|
rv = self.nocache(name=name)
|
|
if not (name is None
|
|
or isinstance(rv, tzlocal_classes)
|
|
or rv is None):
|
|
# tzlocal is slightly more complicated than the other
|
|
# time zone providers because it depends on environment
|
|
# at construction time, so don't cache that.
|
|
#
|
|
# We also cannot store weak references to None, so we
|
|
# will also not store that.
|
|
self.__instances[name] = rv
|
|
else:
|
|
# No need for strong caching, return immediately
|
|
return rv
|
|
|
|
self.__strong_cache[name] = self.__strong_cache.pop(name, rv)
|
|
|
|
if len(self.__strong_cache) > self.__strong_cache_size:
|
|
self.__strong_cache.popitem(last=False)
|
|
|
|
return rv
|
|
|
|
def set_cache_size(self, size):
|
|
with self._cache_lock:
|
|
self.__strong_cache_size = size
|
|
while len(self.__strong_cache) > size:
|
|
self.__strong_cache.popitem(last=False)
|
|
|
|
def cache_clear(self):
|
|
with self._cache_lock:
|
|
self.__instances = weakref.WeakValueDictionary()
|
|
self.__strong_cache.clear()
|
|
|
|
@staticmethod
|
|
def nocache(name=None):
|
|
"""A non-cached version of gettz"""
|
|
tz = None
|
|
if not name:
|
|
try:
|
|
name = os.environ["TZ"]
|
|
except KeyError:
|
|
pass
|
|
if name is None or name == ":":
|
|
for filepath in TZFILES:
|
|
if not os.path.isabs(filepath):
|
|
filename = filepath
|
|
for path in TZPATHS:
|
|
filepath = os.path.join(path, filename)
|
|
if os.path.isfile(filepath):
|
|
break
|
|
else:
|
|
continue
|
|
if os.path.isfile(filepath):
|
|
try:
|
|
tz = tzfile(filepath)
|
|
break
|
|
except (IOError, OSError, ValueError):
|
|
pass
|
|
else:
|
|
tz = tzlocal()
|
|
else:
|
|
try:
|
|
if name.startswith(":"):
|
|
name = name[1:]
|
|
except TypeError as e:
|
|
if isinstance(name, bytes):
|
|
new_msg = "gettz argument should be str, not bytes"
|
|
six.raise_from(TypeError(new_msg), e)
|
|
else:
|
|
raise
|
|
if os.path.isabs(name):
|
|
if os.path.isfile(name):
|
|
tz = tzfile(name)
|
|
else:
|
|
tz = None
|
|
else:
|
|
for path in TZPATHS:
|
|
filepath = os.path.join(path, name)
|
|
if not os.path.isfile(filepath):
|
|
filepath = filepath.replace(' ', '_')
|
|
if not os.path.isfile(filepath):
|
|
continue
|
|
try:
|
|
tz = tzfile(filepath)
|
|
break
|
|
except (IOError, OSError, ValueError):
|
|
pass
|
|
else:
|
|
tz = None
|
|
if tzwin is not None:
|
|
try:
|
|
tz = tzwin(name)
|
|
except (WindowsError, UnicodeEncodeError):
|
|
# UnicodeEncodeError is for Python 2.7 compat
|
|
tz = None
|
|
|
|
if not tz:
|
|
from dateutil.zoneinfo import get_zonefile_instance
|
|
tz = get_zonefile_instance().get(name)
|
|
|
|
if not tz:
|
|
for c in name:
|
|
# name is not a tzstr unless it has at least
|
|
# one offset. For short values of "name", an
|
|
# explicit for loop seems to be the fastest way
|
|
# To determine if a string contains a digit
|
|
if c in "0123456789":
|
|
try:
|
|
tz = tzstr(name)
|
|
except ValueError:
|
|
pass
|
|
break
|
|
else:
|
|
if name in ("GMT", "UTC"):
|
|
tz = UTC
|
|
elif name in time.tzname:
|
|
tz = tzlocal()
|
|
return tz
|
|
|
|
return GettzFunc()
|
|
|
|
|
|
gettz = __get_gettz()
|
|
del __get_gettz
|
|
|
|
|
|
def datetime_exists(dt, tz=None):
|
|
"""
|
|
Given a datetime and a time zone, determine whether or not a given datetime
|
|
would fall in a gap.
|
|
|
|
:param dt:
|
|
A :class:`datetime.datetime` (whose time zone will be ignored if ``tz``
|
|
is provided.)
|
|
|
|
:param tz:
|
|
A :class:`datetime.tzinfo` with support for the ``fold`` attribute. If
|
|
``None`` or not provided, the datetime's own time zone will be used.
|
|
|
|
:return:
|
|
Returns a boolean value whether or not the "wall time" exists in
|
|
``tz``.
|
|
|
|
.. versionadded:: 2.7.0
|
|
"""
|
|
if tz is None:
|
|
if dt.tzinfo is None:
|
|
raise ValueError('Datetime is naive and no time zone provided.')
|
|
tz = dt.tzinfo
|
|
|
|
dt = dt.replace(tzinfo=None)
|
|
|
|
# This is essentially a test of whether or not the datetime can survive
|
|
# a round trip to UTC.
|
|
dt_rt = dt.replace(tzinfo=tz).astimezone(UTC).astimezone(tz)
|
|
dt_rt = dt_rt.replace(tzinfo=None)
|
|
|
|
return dt == dt_rt
|
|
|
|
|
|
def datetime_ambiguous(dt, tz=None):
|
|
"""
|
|
Given a datetime and a time zone, determine whether or not a given datetime
|
|
is ambiguous (i.e if there are two times differentiated only by their DST
|
|
status).
|
|
|
|
:param dt:
|
|
A :class:`datetime.datetime` (whose time zone will be ignored if ``tz``
|
|
is provided.)
|
|
|
|
:param tz:
|
|
A :class:`datetime.tzinfo` with support for the ``fold`` attribute. If
|
|
``None`` or not provided, the datetime's own time zone will be used.
|
|
|
|
:return:
|
|
Returns a boolean value whether or not the "wall time" is ambiguous in
|
|
``tz``.
|
|
|
|
.. versionadded:: 2.6.0
|
|
"""
|
|
if tz is None:
|
|
if dt.tzinfo is None:
|
|
raise ValueError('Datetime is naive and no time zone provided.')
|
|
|
|
tz = dt.tzinfo
|
|
|
|
# If a time zone defines its own "is_ambiguous" function, we'll use that.
|
|
is_ambiguous_fn = getattr(tz, 'is_ambiguous', None)
|
|
if is_ambiguous_fn is not None:
|
|
try:
|
|
return tz.is_ambiguous(dt)
|
|
except Exception:
|
|
pass
|
|
|
|
# If it doesn't come out and tell us it's ambiguous, we'll just check if
|
|
# the fold attribute has any effect on this particular date and time.
|
|
dt = dt.replace(tzinfo=tz)
|
|
wall_0 = enfold(dt, fold=0)
|
|
wall_1 = enfold(dt, fold=1)
|
|
|
|
same_offset = wall_0.utcoffset() == wall_1.utcoffset()
|
|
same_dst = wall_0.dst() == wall_1.dst()
|
|
|
|
return not (same_offset and same_dst)
|
|
|
|
|
|
def resolve_imaginary(dt):
|
|
"""
|
|
Given a datetime that may be imaginary, return an existing datetime.
|
|
|
|
This function assumes that an imaginary datetime represents what the
|
|
wall time would be in a zone had the offset transition not occurred, so
|
|
it will always fall forward by the transition's change in offset.
|
|
|
|
.. doctest::
|
|
|
|
>>> from dateutil import tz
|
|
>>> from datetime import datetime
|
|
>>> NYC = tz.gettz('America/New_York')
|
|
>>> print(tz.resolve_imaginary(datetime(2017, 3, 12, 2, 30, tzinfo=NYC)))
|
|
2017-03-12 03:30:00-04:00
|
|
|
|
>>> KIR = tz.gettz('Pacific/Kiritimati')
|
|
>>> print(tz.resolve_imaginary(datetime(1995, 1, 1, 12, 30, tzinfo=KIR)))
|
|
1995-01-02 12:30:00+14:00
|
|
|
|
As a note, :func:`datetime.astimezone` is guaranteed to produce a valid,
|
|
existing datetime, so a round-trip to and from UTC is sufficient to get
|
|
an extant datetime, however, this generally "falls back" to an earlier time
|
|
rather than falling forward to the STD side (though no guarantees are made
|
|
about this behavior).
|
|
|
|
:param dt:
|
|
A :class:`datetime.datetime` which may or may not exist.
|
|
|
|
:return:
|
|
Returns an existing :class:`datetime.datetime`. If ``dt`` was not
|
|
imaginary, the datetime returned is guaranteed to be the same object
|
|
passed to the function.
|
|
|
|
.. versionadded:: 2.7.0
|
|
"""
|
|
if dt.tzinfo is not None and not datetime_exists(dt):
|
|
|
|
curr_offset = (dt + datetime.timedelta(hours=24)).utcoffset()
|
|
old_offset = (dt - datetime.timedelta(hours=24)).utcoffset()
|
|
|
|
dt += curr_offset - old_offset
|
|
|
|
return dt
|
|
|
|
|
|
def _datetime_to_timestamp(dt):
|
|
"""
|
|
Convert a :class:`datetime.datetime` object to an epoch timestamp in
|
|
seconds since January 1, 1970, ignoring the time zone.
|
|
"""
|
|
return (dt.replace(tzinfo=None) - EPOCH).total_seconds()
|
|
|
|
|
|
if sys.version_info >= (3, 6):
|
|
def _get_supported_offset(second_offset):
|
|
return second_offset
|
|
else:
|
|
def _get_supported_offset(second_offset):
|
|
# For python pre-3.6, round to full-minutes if that's not the case.
|
|
# Python's datetime doesn't accept sub-minute timezones. Check
|
|
# http://python.org/sf/1447945 or https://bugs.python.org/issue5288
|
|
# for some information.
|
|
old_offset = second_offset
|
|
calculated_offset = 60 * ((second_offset + 30) // 60)
|
|
return calculated_offset
|
|
|
|
|
|
try:
|
|
# Python 3.7 feature
|
|
from contextlib import nullcontext as _nullcontext
|
|
except ImportError:
|
|
class _nullcontext(object):
|
|
"""
|
|
Class for wrapping contexts so that they are passed through in a
|
|
with statement.
|
|
"""
|
|
def __init__(self, context):
|
|
self.context = context
|
|
|
|
def __enter__(self):
|
|
return self.context
|
|
|
|
def __exit__(*args, **kwargs):
|
|
pass
|
|
|
|
# vim:ts=4:sw=4:et
|