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Diffstat (limited to 'Windows/dateutil/tz/tz.py')
| -rw-r--r-- | Windows/dateutil/tz/tz.py | 1836 |
1 files changed, 0 insertions, 1836 deletions
diff --git a/Windows/dateutil/tz/tz.py b/Windows/dateutil/tz/tz.py deleted file mode 100644 index d05414e7..00000000 --- a/Windows/dateutil/tz/tz.py +++ /dev/null @@ -1,1836 +0,0 @@ -# -*- coding: utf-8 -*- -""" -This module offers timezone implementations subclassing the abstract -:py:class:`datetime.tzinfo` type. There are classes to handle tzfile format -files (usually are in :file:`/etc/localtime`, :file:`/usr/share/zoneinfo`, -etc), TZ environment string (in all known formats), given ranges (with help -from relative deltas), local machine timezone, fixed offset timezone, and UTC -timezone. -""" -import datetime -import struct -import time -import sys -import os -import bisect -import weakref -from collections import OrderedDict - -import six -from six import string_types -from six.moves import _thread -from ._common import tzname_in_python2, _tzinfo -from ._common import tzrangebase, enfold -from ._common import _validate_fromutc_inputs - -from ._factories import _TzSingleton, _TzOffsetFactory -from ._factories import _TzStrFactory -try: - from .win import tzwin, tzwinlocal -except ImportError: - tzwin = tzwinlocal = None - -# For warning about rounding tzinfo -from warnings import warn - -ZERO = datetime.timedelta(0) -EPOCH = datetime.datetime.utcfromtimestamp(0) -EPOCHORDINAL = EPOCH.toordinal() - - -@six.add_metaclass(_TzSingleton) -class tzutc(datetime.tzinfo): - """ - This is a tzinfo object that represents the UTC time zone. - - **Examples:** - - .. doctest:: - - >>> from datetime import * - >>> from dateutil.tz import * - - >>> datetime.now() - datetime.datetime(2003, 9, 27, 9, 40, 1, 521290) - - >>> datetime.now(tzutc()) - datetime.datetime(2003, 9, 27, 12, 40, 12, 156379, tzinfo=tzutc()) - - >>> datetime.now(tzutc()).tzname() - 'UTC' - - .. versionchanged:: 2.7.0 - ``tzutc()`` is now a singleton, so the result of ``tzutc()`` will - always return the same object. - - .. doctest:: - - >>> from dateutil.tz import tzutc, UTC - >>> tzutc() is tzutc() - True - >>> tzutc() is UTC - True - """ - def utcoffset(self, dt): - return ZERO - - def dst(self, dt): - return ZERO - - @tzname_in_python2 - def tzname(self, dt): - return "UTC" - - def is_ambiguous(self, dt): - """ - 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 - """ - return False - - @_validate_fromutc_inputs - def fromutc(self, dt): - """ - Fast track version of fromutc() returns the original ``dt`` object for - any valid :py:class:`datetime.datetime` object. - """ - return dt - - def __eq__(self, other): - if not isinstance(other, (tzutc, tzoffset)): - return NotImplemented - - return (isinstance(other, tzutc) or - (isinstance(other, tzoffset) and other._offset == ZERO)) - - __hash__ = None - - def __ne__(self, other): - return not (self == other) - - def __repr__(self): - return "%s()" % self.__class__.__name__ - - __reduce__ = object.__reduce__ - - -@six.add_metaclass(_TzOffsetFactory) -class tzoffset(datetime.tzinfo): - """ - A simple class for representing a fixed offset from UTC. - - :param name: - The timezone name, to be returned when ``tzname()`` is called. - :param offset: - The time zone offset in seconds, or (since version 2.6.0, represented - as a :py:class:`datetime.timedelta` object). - """ - def __init__(self, name, offset): - self._name = name - - try: - # Allow a timedelta - offset = offset.total_seconds() - except (TypeError, AttributeError): - pass - - self._offset = datetime.timedelta(seconds=_get_supported_offset(offset)) - - def utcoffset(self, dt): - return self._offset - - def dst(self, dt): - return ZERO - - @tzname_in_python2 - def tzname(self, dt): - return self._name - - @_validate_fromutc_inputs - def fromutc(self, dt): - return dt + self._offset - - def is_ambiguous(self, dt): - """ - 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 - """ - return False - - def __eq__(self, other): - if not isinstance(other, tzoffset): - return NotImplemented - - return self._offset == other._offset - - __hash__ = None - - def __ne__(self, other): - return not (self == other) - - def __repr__(self): - return "%s(%s, %s)" % (self.__class__.__name__, - repr(self._name), - int(self._offset.total_seconds())) - - __reduce__ = object.__reduce__ - - -class tzlocal(_tzinfo): - """ - A :class:`tzinfo` subclass built around the ``time`` timezone functions. - """ - def __init__(self): - super(tzlocal, self).__init__() - - self._std_offset = datetime.timedelta(seconds=-time.timezone) - if time.daylight: - self._dst_offset = datetime.timedelta(seconds=-time.altzone) - else: - self._dst_offset = self._std_offset - - self._dst_saved = self._dst_offset - self._std_offset - self._hasdst = bool(self._dst_saved) - self._tznames = tuple(time.tzname) - - def utcoffset(self, dt): - if dt is None and self._hasdst: - return None - - if self._isdst(dt): - return self._dst_offset - else: - return self._std_offset - - def dst(self, dt): - if dt is None and self._hasdst: - return None - - if self._isdst(dt): - return self._dst_offset - self._std_offset - else: - return ZERO - - @tzname_in_python2 - def tzname(self, dt): - return self._tznames[self._isdst(dt)] - - def is_ambiguous(self, dt): - """ - 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 - """ - naive_dst = self._naive_is_dst(dt) - return (not naive_dst and - (naive_dst != self._naive_is_dst(dt - self._dst_saved))) - - def _naive_is_dst(self, dt): - timestamp = _datetime_to_timestamp(dt) - return time.localtime(timestamp + time.timezone).tm_isdst - - def _isdst(self, dt, fold_naive=True): - # We can't use mktime here. It is unstable when deciding if - # the hour near to a change is DST or not. - # - # timestamp = time.mktime((dt.year, dt.month, dt.day, dt.hour, - # dt.minute, dt.second, dt.weekday(), 0, -1)) - # return time.localtime(timestamp).tm_isdst - # - # The code above yields the following result: - # - # >>> import tz, datetime - # >>> t = tz.tzlocal() - # >>> datetime.datetime(2003,2,15,23,tzinfo=t).tzname() - # 'BRDT' - # >>> datetime.datetime(2003,2,16,0,tzinfo=t).tzname() - # 'BRST' - # >>> datetime.datetime(2003,2,15,23,tzinfo=t).tzname() - # 'BRST' - # >>> datetime.datetime(2003,2,15,22,tzinfo=t).tzname() - # 'BRDT' - # >>> datetime.datetime(2003,2,15,23,tzinfo=t).tzname() - # 'BRDT' - # - # Here is a more stable implementation: - # - if not self._hasdst: - return False - - # Check for ambiguous times: - dstval = self._naive_is_dst(dt) - fold = getattr(dt, 'fold', None) - - if self.is_ambiguous(dt): - if fold is not None: - return not self._fold(dt) - else: - return True - - return dstval - - def __eq__(self, other): - if isinstance(other, tzlocal): - return (self._std_offset == other._std_offset and - self._dst_offset == other._dst_offset) - elif isinstance(other, tzutc): - return (not self._hasdst and - self._tznames[0] in {'UTC', 'GMT'} and - self._std_offset == ZERO) - elif isinstance(other, tzoffset): - return (not self._hasdst and - self._tznames[0] == other._name and - self._std_offset == other._offset) - else: - return NotImplemented - - __hash__ = None - - def __ne__(self, other): - return not (self == other) - - def __repr__(self): - return "%s()" % self.__class__.__name__ - - __reduce__ = object.__reduce__ - - -class _ttinfo(object): - __slots__ = ["offset", "delta", "isdst", "abbr", - "isstd", "isgmt", "dstoffset"] - - def __init__(self): - for attr in self.__slots__: - setattr(self, attr, None) - - def __repr__(self): - l = [] - for attr in self.__slots__: - value = getattr(self, attr) - if value is not None: - l.append("%s=%s" % (attr, repr(value))) - return "%s(%s)" % (self.__class__.__name__, ", ".join(l)) - - def __eq__(self, other): - if not isinstance(other, _ttinfo): - return NotImplemented - - return (self.offset == other.offset and - self.delta == other.delta and - self.isdst == other.isdst and - self.abbr == other.abbr and - self.isstd == other.isstd and - self.isgmt == other.isgmt and - self.dstoffset == other.dstoffset) - - __hash__ = None - - def __ne__(self, other): - return not (self == other) - - def __getstate__(self): - state = {} - for name in self.__slots__: - state[name] = getattr(self, name, None) - return state - - def __setstate__(self, state): - for name in self.__slots__: - if name in state: - setattr(self, name, state[name]) - - -class _tzfile(object): - """ - Lightweight class for holding the relevant transition and time zone - information read from binary tzfiles. - """ - attrs = ['trans_list', 'trans_list_utc', 'trans_idx', 'ttinfo_list', - 'ttinfo_std', 'ttinfo_dst', 'ttinfo_before', 'ttinfo_first'] - - def __init__(self, **kwargs): - for attr in self.attrs: - setattr(self, attr, kwargs.get(attr, None)) - - -class tzfile(_tzinfo): - """ - This is a ``tzinfo`` subclass thant allows one to use the ``tzfile(5)`` - format timezone files to extract current and historical zone information. - - :param fileobj: - This can be an opened file stream or a file name that the time zone - information can be read from. - - :param filename: - This is an optional parameter specifying the source of the time zone - information in the event that ``fileobj`` is a file object. If omitted - and ``fileobj`` is a file stream, this parameter will be set either to - ``fileobj``'s ``name`` attribute or to ``repr(fileobj)``. - - See `Sources for Time Zone and Daylight Saving Time Data - <https://data.iana.org/time-zones/tz-link.html>`_ for more information. - Time zone files can be compiled from the `IANA Time Zone database files - <https://www.iana.org/time-zones>`_ with the `zic time zone compiler - <https://www.freebsd.org/cgi/man.cgi?query=zic&sektion=8>`_ - - .. note:: - - Only construct a ``tzfile`` directly if you have a specific timezone - file on disk that you want to read into a Python ``tzinfo`` object. - If you want to get a ``tzfile`` representing a specific IANA zone, - (e.g. ``'America/New_York'``), you should call - :func:`dateutil.tz.gettz` with the zone identifier. - - - **Examples:** - - Using the US Eastern time zone as an example, we can see that a ``tzfile`` - provides time zone information for the standard Daylight Saving offsets: - - .. testsetup:: tzfile - - from dateutil.tz import gettz - from datetime import datetime - - .. doctest:: tzfile - - >>> NYC = gettz('America/New_York') - >>> NYC - tzfile('/usr/share/zoneinfo/America/New_York') - - >>> print(datetime(2016, 1, 3, tzinfo=NYC)) # EST - 2016-01-03 00:00:00-05:00 - - >>> print(datetime(2016, 7, 7, tzinfo=NYC)) # EDT - 2016-07-07 00:00:00-04:00 - - - The ``tzfile`` structure contains a fully history of the time zone, - so historical dates will also have the right offsets. For example, before - the adoption of the UTC standards, New York used local solar mean time: - - .. doctest:: tzfile - - >>> print(datetime(1901, 4, 12, tzinfo=NYC)) # LMT - 1901-04-12 00:00:00-04:56 - - And during World War II, New York was on "Eastern War Time", which was a - state of permanent daylight saving time: - - .. doctest:: tzfile - - >>> print(datetime(1944, 2, 7, tzinfo=NYC)) # EWT - 1944-02-07 00:00:00-04:00 - - """ - - def __init__(self, fileobj, filename=None): - super(tzfile, self).__init__() - - file_opened_here = False - if isinstance(fileobj, string_types): - self._filename = fileobj - fileobj = open(fileobj, 'rb') - file_opened_here = True - elif filename is not None: - self._filename = filename - elif hasattr(fileobj, "name"): - self._filename = fileobj.name - else: - self._filename = repr(fileobj) - - if fileobj is not None: - if not file_opened_here: - fileobj = _nullcontext(fileobj) - - with fileobj as file_stream: - tzobj = self._read_tzfile(file_stream) - - self._set_tzdata(tzobj) - - def _set_tzdata(self, tzobj): - """ Set the time zone data of this object from a _tzfile object """ - # Copy the relevant attributes over as private attributes - for attr in _tzfile.attrs: - setattr(self, '_' + attr, getattr(tzobj, attr)) - - def _read_tzfile(self, fileobj): - out = _tzfile() - - # From tzfile(5): - # - # The time zone information files used by tzset(3) - # begin with the magic characters "TZif" to identify - # them as time zone information files, followed by - # sixteen bytes reserved for future use, followed by - # six four-byte values of type long, written in a - # ``standard'' byte order (the high-order byte - # of the value is written first). - if fileobj.read(4).decode() != "TZif": - raise ValueError("magic not found") - - fileobj.read(16) - - ( - # The number of UTC/local indicators stored in the file. - ttisgmtcnt, - - # The number of standard/wall indicators stored in the file. - ttisstdcnt, - - # The number of leap seconds for which data is - # stored in the file. - leapcnt, - - # The number of "transition times" for which data - # is stored in the file. - timecnt, - - # The number of "local time types" for which data - # is stored in the file (must not be zero). - typecnt, - - # The number of characters of "time zone - # abbreviation strings" stored in the file. - charcnt, - - ) = struct.unpack(">6l", fileobj.read(24)) - - # The above header is followed by tzh_timecnt four-byte - # values of type long, sorted in ascending order. - # These values are written in ``standard'' byte order. - # Each is used as a transition time (as returned by - # time(2)) at which the rules for computing local time - # change. - - if timecnt: - out.trans_list_utc = list(struct.unpack(">%dl" % timecnt, - fileobj.read(timecnt*4))) - else: - out.trans_list_utc = [] - - # Next come tzh_timecnt one-byte values of type unsigned - # char; each one tells which of the different types of - # ``local time'' types described in the file is associated - # with the same-indexed transition time. These values - # serve as indices into an array of ttinfo structures that - # appears next in the file. - - if timecnt: - out.trans_idx = struct.unpack(">%dB" % timecnt, - 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: - if name.startswith(":"): - name = name[1:] - 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 = tzutc() - 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(tzutc()).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 contextmanager 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 |