view env/lib/python3.9/site-packages/isodate/tzinfo.py @ 0:4f3585e2f14b draft default tip

"planemo upload commit 60cee0fc7c0cda8592644e1aad72851dec82c959"

'''
This module provides some datetime.tzinfo implementations.

All those classes are taken from the Python documentation.
'''
from datetime import timedelta, tzinfo
import time

ZERO = timedelta(0)
# constant for zero time offset.


class Utc(tzinfo):
    '''UTC

    Universal time coordinated time zone.
    '''

    def utcoffset(self, dt):
        '''
        Return offset from UTC in minutes east of UTC, which is ZERO for UTC.
        '''
        return ZERO

    def tzname(self, dt):
        '''
        Return the time zone name corresponding to the datetime object dt,
        as a string.
        '''
        return "UTC"

    def dst(self, dt):
        '''
        Return the daylight saving time (DST) adjustment, in minutes east
        of UTC.
        '''
        return ZERO

    def __reduce__(self):
        '''
        When unpickling a Utc object, return the default instance below, UTC.
        '''
        return _Utc, ()


UTC = Utc()
# the default instance for UTC.


def _Utc():
    '''
    Helper function for unpickling a Utc object.
    '''
    return UTC


class FixedOffset(tzinfo):
    '''
    A class building tzinfo objects for fixed-offset time zones.

    Note that FixedOffset(0, 0, "UTC") or FixedOffset() is a different way to
    build a UTC tzinfo object.
    '''

    def __init__(self, offset_hours=0, offset_minutes=0, name="UTC"):
        '''
        Initialise an instance with time offset and name.
        The time offset should be positive for time zones east of UTC
        and negate for time zones west of UTC.
        '''
        self.__offset = timedelta(hours=offset_hours, minutes=offset_minutes)
        self.__name = name

    def utcoffset(self, dt):
        '''
        Return offset from UTC in minutes of UTC.
        '''
        return self.__offset

    def tzname(self, dt):
        '''
        Return the time zone name corresponding to the datetime object dt, as a
        string.
        '''
        return self.__name

    def dst(self, dt):
        '''
        Return the daylight saving time (DST) adjustment, in minutes east of
        UTC.
        '''
        return ZERO

    def __repr__(self):
        '''
        Return nicely formatted repr string.
        '''
        return "<FixedOffset %r>" % self.__name


STDOFFSET = timedelta(seconds=-time.timezone)
# locale time zone offset

# calculate local daylight saving offset if any.
if time.daylight:
    DSTOFFSET = timedelta(seconds=-time.altzone)
else:
    DSTOFFSET = STDOFFSET

DSTDIFF = DSTOFFSET - STDOFFSET
# difference between local time zone and local DST time zone


class LocalTimezone(tzinfo):
    """
    A class capturing the platform's idea of local time.
    """

    def utcoffset(self, dt):
        '''
        Return offset from UTC in minutes of UTC.
        '''
        if self._isdst(dt):
            return DSTOFFSET
        else:
            return STDOFFSET

    def dst(self, dt):
        '''
        Return daylight saving offset.
        '''
        if self._isdst(dt):
            return DSTDIFF
        else:
            return ZERO

    def tzname(self, dt):
        '''
        Return the time zone name corresponding to the datetime object dt, as a
        string.
        '''
        return time.tzname[self._isdst(dt)]

    def _isdst(self, dt):
        '''
        Returns true if DST is active for given datetime object dt.
        '''
        tt = (dt.year, dt.month, dt.day,
              dt.hour, dt.minute, dt.second,
              dt.weekday(), 0, -1)
        stamp = time.mktime(tt)
        tt = time.localtime(stamp)
        return tt.tm_isdst > 0


# the default instance for local time zone.
LOCAL = LocalTimezone()