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Fix bug of implementation of algorithm for calculating the date from year, week

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of the year, and day of the week.  Was not taking into consideration properly
the issue of when %U is used for the week of the year but the year starts on
Monday.

Closes bug #1045381 again.
This commit is contained in:
Brett Cannon 2004-10-28 04:49:21 +00:00
parent 79d9bfa28f
commit 14adbe77b5
2 changed files with 30 additions and 13 deletions
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22
Lib/_strptime.py
View File

@ -391,25 +391,27 @@ def strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
# If we know the week of the year and what day of that week, we can figure
# out the Julian day of the year
# Calculations below assume 0 is a Monday
if julian == -1 and week_of_year != -1 and weekday != -1 and year != -1:
# Adjust for U directive so that calculations are not dependent on
# directive used to figure out week of year
if weekday == 6 and week_of_year_start == 6:
week_of_year -= 1
# For some reason when Dec 31 falls on a Monday the week of the year is
# off by a week; verified on both OS X and Solaris.
elif weekday == 0 and week_of_year_start == 6 and week_of_year >= 52:
week_of_year += 1
if julian == -1 and week_of_year != -1 and weekday != -1:
# Calculate how many days in week 0
first_weekday = datetime_date(year, 1, 1).weekday()
preceeding_days = 7 - first_weekday
if preceeding_days == 7:
preceeding_days = 0
# Adjust for U directive so that calculations are not dependent on
# directive used to figure out week of year
if weekday == 6 and week_of_year_start == 6:
week_of_year -= 1
# If a year starts and ends on a Monday but a week is specified to
# start on a Sunday we need to up the week to counter-balance the fact
# that with %W that first Monday starts week 1 while with %U that is
# week 0 and thus shifts everything by a week
if weekday == 0 and first_weekday == 0 and week_of_year_start == 6:
week_of_year += 1
# If in week 0, then just figure out how many days from Jan 1 to day of
# week specified, else calculate by multiplying week of year by 7,
# adding in days in week 0, and the number of days from Monday to the
# day of the week
if not week_of_year:
if week_of_year == 0:
julian = 1 + weekday - first_weekday
else:
days_to_week = preceeding_days + (7 * (week_of_year - 1))

21
Lib/test/test_strptime.py
View File

@ -424,20 +424,35 @@ class CalculationTests(unittest.TestCase):
def test_helper(ymd_tuple, test_reason):
for directive in ('W', 'U'):
format_string = "%%Y %%%s %%w" % directive
strp_input = datetime_date(*ymd_tuple).strftime(format_string)
dt_date = datetime_date(*ymd_tuple)
strp_input = dt_date.strftime(format_string)
strp_output = _strptime.strptime(strp_input, format_string)
self.failUnless(strp_output[:3] == ymd_tuple,
"%s(%s) test failed w/ '%s': %s != %s" %
"%s(%s) test failed w/ '%s': %s != %s (%s != %s)" %
(test_reason, directive, strp_input,
strp_output[:3], ymd_tuple[:3]))
strp_output[:3], ymd_tuple,
strp_output[7], dt_date.timetuple()[7]))
test_helper((1901, 1, 3), "week 0")
test_helper((1901, 1, 8), "common case")
test_helper((1901, 1, 13), "day on Sunday")
test_helper((1901, 1, 14), "day on Monday")
test_helper((1905, 1, 1), "Jan 1 on Sunday")
test_helper((1906, 1, 1), "Jan 1 on Monday")
test_helper((1906, 1, 7), "first Sunday in a year starting on Monday")
test_helper((1905, 12, 31), "Dec 31 on Sunday")
test_helper((1906, 12, 31), "Dec 31 on Monday")
test_helper((2008, 12, 29), "Monday in the last week of the year")
test_helper((2008, 12, 22), "Monday in the second-to-last week of the "
"year")
test_helper((1978, 10, 23), "randomly chosen date")
test_helper((2004, 12, 18), "randomly chosen date")
test_helper((1978, 10, 23), "year starting and ending on Monday while "
"date not on Sunday or Monday")
test_helper((1917, 12, 17), "year starting and ending on Monday with "
"a Monday not at the beginning or end "
"of the year")
test_helper((1917, 12, 31), "Dec 31 on Monday with year starting and "
"ending on Monday")
class CacheTests(unittest.TestCase):