from __future__ import division
from datetime import timedelta, tzinfo
from copy import deepcopy
class FixedOffset(tzinfo):
'''
Represent a timezone with a fixed offset from UTC and no adjustment for
DST.
>>> FixedOffset(4,0)
<UTC+04:00>
>>> FixedOffset(-4,0)
<UTC-04:00>
>>> FixedOffset(4,30)
<UTC+04:30>
>>> tz = FixedOffset(-5,0)
>>> tz.dst(None)
datetime.timedelta(0)
The class tries to do the right thing with the sign
of the time zone offset:
>>> FixedOffset(-9,30)
<UTC-09:30>
>>> FixedOffset(-9,-30)
Traceback (most recent call last):
...
ValueError: minutes must not be negative
Offsets must thus be normalized so that the minute value is positive:
>>> FixedOffset(-8,30)
<UTC-08:30>
'''
def __init__(self, hours, minutes):
'''
Create a new FixedOffset instance with the given offset.
'''
tzinfo.__init__(self)
if minutes < 0:
raise ValueError("minutes must not be negative")
if hours < 0:
minutes *= -1
self.__offset = timedelta(hours=hours,
minutes=minutes)
self.__name = "UTC" + timezone(timedelta_seconds(self.__offset))
def dst(self, dt):
'''
Return offset for DST. Always returns timedelta(0).
'''
return timedelta(0)
def utcoffset(self, dt):
'''
Return offset from UTC.
'''
return self.__offset
def tzname(self, dt):
'''
Return name of timezone.
'''
return self.__name
def __repr__(self):
return "<{0}>".format(self.tzname(None))
def __deepcopy__(self, memo):
cls = self.__class__
result = cls.__new__(cls)
memo[id(self)] = result
for k, v in self.__dict__.items():
setattr(result, k, deepcopy(v, memo))
return result
def timedelta_seconds(td):
'''
Return the offset stored by a :class:`datetime.timedelta` object as an
integer number of seconds. Microseconds, if present, are rounded to
the nearest second.
Delegates to
:meth:`timedelta.total_seconds() <datetime.timedelta.total_seconds()>`
if available.
>>> timedelta_seconds(timedelta(hours=1))
3600
>>> timedelta_seconds(timedelta(hours=-1))
-3600
>>> timedelta_seconds(timedelta(hours=1, minutes=30))
5400
>>> timedelta_seconds(timedelta(hours=1, minutes=30,
... microseconds=300000))
5400
>>> timedelta_seconds(timedelta(hours=1, minutes=30,
... microseconds=900000))
5401
'''
try:
return int(round(td.total_seconds()))
except AttributeError:
days = td.days
seconds = td.seconds
microseconds = td.microseconds
return int(round((days * 86400) + seconds + (microseconds / 1000000)))
def timezone(utcoffset):
'''
Return a string representing the timezone offset.
Remaining seconds are rounded to the nearest minute.
>>> timezone(3600)
'+01:00'
>>> timezone(5400)
'+01:30'
>>> timezone(-28800)
'-08:00'
'''
hours, seconds = divmod(abs(utcoffset), 3600)
minutes = round(float(seconds) / 60)
if utcoffset >= 0:
sign = '+'
else:
sign = '-'
return '{0}{1:02d}:{2:02d}'.format(sign, int(hours), int(minutes))