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# These classes override date and datetime to ensure that strftime('%Y')
# returns four digits (with leading zeros) on years < 1000.
# https://bugs.python.org/issue13305
#
# Based on code submitted to comp.lang.python by Andrew Dalke
#
# >>> datetime_safe.date(10, 8, 2).strftime("%Y/%m/%d was a %A")
# '0010/08/02 was a Monday'
import time as ttime
from datetime import (
date as real_date, datetime as real_datetime, time as real_time,
)
from django.utils.regex_helper import _lazy_re_compile
class date(real_date):
def strftime(self, fmt):
return strftime(self, fmt)
class datetime(real_datetime):
def strftime(self, fmt):
return strftime(self, fmt)
@classmethod
def combine(cls, date, time):
return cls(date.year, date.month, date.day,
time.hour, time.minute, time.second,
time.microsecond, time.tzinfo)
def date(self):
return date(self.year, self.month, self.day)
class time(real_time):
pass
def new_date(d):
"Generate a safe date from a datetime.date object."
return date(d.year, d.month, d.day)
def new_datetime(d):
"""
Generate a safe datetime from a datetime.date or datetime.datetime object.
"""
kw = [d.year, d.month, d.day]
if isinstance(d, real_datetime):
kw.extend([d.hour, d.minute, d.second, d.microsecond, d.tzinfo])
return datetime(*kw)
# This library does not support strftime's "%s" or "%y" format strings.
# Allowed if there's an even number of "%"s because they are escaped.
_illegal_formatting = _lazy_re_compile(r"((^|[^%])(%%)*%[sy])")
def _findall(text, substr):
# Also finds overlaps
sites = []
i = 0
while True:
i = text.find(substr, i)
if i == -1:
break
sites.append(i)
i += 1
return sites
def strftime(dt, fmt):
if dt.year >= 1000:
return super(type(dt), dt).strftime(fmt)
illegal_formatting = _illegal_formatting.search(fmt)
if illegal_formatting:
raise TypeError('strftime of dates before 1000 does not handle ' + illegal_formatting[0])
year = dt.year
# For every non-leap year century, advance by
# 6 years to get into the 28-year repeat cycle
delta = 2000 - year
off = 6 * (delta // 100 + delta // 400)
year = year + off
# Move to around the year 2000
year = year + ((2000 - year) // 28) * 28
timetuple = dt.timetuple()
s1 = ttime.strftime(fmt, (year,) + timetuple[1:])
sites1 = _findall(s1, str(year))
s2 = ttime.strftime(fmt, (year + 28,) + timetuple[1:])
sites2 = _findall(s2, str(year + 28))
sites = []
for site in sites1:
if site in sites2:
sites.append(site)
s = s1
syear = "%04d" % dt.year
for site in sites:
s = s[:site] + syear + s[site + 4:]
return s
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