_strptime.py

"""Strptime-related classes and functions.

CLASSES:
 LocaleTime -- Discovers and stores locale-specific time information
 TimeRE -- Creates regexes for pattern matching a string of text containing
 time information

FUNCTIONS:
 _getlang -- Figure out what language is being used for the locale
 strptime -- Calculates the time struct represented by the passed-in string

"""
importos
importtime
importlocale
importcalendar
fromreimportcompileasre_compile
fromreimportsubasre_sub
fromreimportIGNORECASE
fromreimportescapeasre_escape
fromdatetimeimport (dateasdatetime_date,
timedeltaasdatetime_timedelta,
timezoneasdatetime_timezone)
from_threadimportallocate_lockas_thread_allocate_lock

__all__= []

def_getlang():
# Figure out what the current language is set to.
returnlocale.getlocale(locale.LC_TIME)

def_findall(haystack, needle):
# Find all positions of needle in haystack.
ifnotneedle:
return
i=0
whileTrue:
i=haystack.find(needle, i)
ifi<0:
break
yieldi
i+=len(needle)

classLocaleTime(object):
"""Stores and handles locale-specific information related to time.

 ATTRIBUTES:
 f_weekday -- full weekday names (7-item list)
 a_weekday -- abbreviated weekday names (7-item list)
 f_month -- full month names (13-item list; dummy value in [0], which
 is added by code)
 a_month -- abbreviated month names (13-item list, dummy value in
 [0], which is added by code)
 am_pm -- AM/PM representation (2-item list)
 LC_date_time -- format string for date/time representation (string)
 LC_date -- format string for date representation (string)
 LC_time -- format string for time representation (string)
 timezone -- daylight- and non-daylight-savings timezone representation
 (2-item list of sets)
 lang -- Language used by instance (2-item tuple)
 """

def__init__(self):
"""Set all attributes.

 Order of methods called matters for dependency reasons.

 The locale language is set at the offset and then checked again before
 exiting. This is to make sure that the attributes were not set with a
 mix of information from more than one locale. This would most likely
 happen when using threads where one thread calls a locale-dependent
 function while another thread changes the locale while the function in
 the other thread is still running. Proper coding would call for
 locks to prevent changing the locale while locale-dependent code is
 running. The check here is done in case someone does not think about
 doing this.

 Only other possible issue is if someone changed the timezone and did
 not call tz.tzset . That is an issue for the programmer, though,
 since changing the timezone is worthless without that call.

 """
self.lang=_getlang()
self.__calc_weekday()
self.__calc_month()
self.__calc_am_pm()
self.__calc_timezone()
self.__calc_date_time()
if_getlang() !=self.lang:
raiseValueError("locale changed during initialization")
iftime.tzname!=self.tznameortime.daylight!=self.daylight:
raiseValueError("timezone changed during initialization")

def__calc_weekday(self):
# Set self.a_weekday and self.f_weekday using the calendar
# module.
a_weekday= [calendar.day_abbr[i].lower() foriinrange(7)]
f_weekday= [calendar.day_name[i].lower() foriinrange(7)]
self.a_weekday=a_weekday
self.f_weekday=f_weekday

def__calc_month(self):
# Set self.f_month and self.a_month using the calendar module.
a_month= [calendar.month_abbr[i].lower() foriinrange(13)]
f_month= [calendar.month_name[i].lower() foriinrange(13)]
self.a_month=a_month
self.f_month=f_month

def__calc_am_pm(self):
# Set self.am_pm by using time.strftime().

# The magic date (1999,3,17,hour,44,55,2,76,0) is not really that
# magical; just happened to have used it everywhere else where a
# static date was needed.
am_pm= []
forhourin (1, 22):
time_tuple=time.struct_time((1999,3,17,hour,44,55,2,76,0))
# br_FR has AM/PM info (' ',' ').
am_pm.append(time.strftime("%p", time_tuple).lower().strip())
self.am_pm=am_pm

def__calc_date_time(self):
# Set self.date_time, self.date, & self.time by using
# time.strftime().

# Use (1999,3,17,22,44,55,2,76,0) for magic date because the amount of
# overloaded numbers is minimized. The order in which searches for
# values within the format string is very important; it eliminates
# possible ambiguity for what something represents.
time_tuple=time.struct_time((1999,3,17,22,44,55,2,76,0))
time_tuple2=time.struct_time((1999,1,3,1,1,1,6,3,0))
replacement_pairs= [
 ('1999', '%Y'), ('99', '%y'), ('22', '%H'),
 ('44', '%M'), ('55', '%S'), ('76', '%j'),
 ('17', '%d'), ('03', '%m'), ('3', '%m'),
# '3' needed for when no leading zero.
 ('2', '%w'), ('10', '%I'),
# Non-ASCII digits
 ('\u0661\u0669\u0669\u0669', '%Y'),
 ('\u0669\u0669', '%Oy'),
 ('\u0662\u0662', '%OH'),
 ('\u0664\u0664', '%OM'),
 ('\u0665\u0665', '%OS'),
 ('\u0661\u0667', '%Od'),
 ('\u0660\u0663', '%Om'),
 ('\u0663', '%Om'),
 ('\u0662', '%Ow'),
 ('\u0661\u0660', '%OI'),
 ]
date_time= []
fordirectivein ('%c', '%x', '%X'):
current_format=time.strftime(directive, time_tuple).lower()
current_format=current_format.replace('%', '%%')
# The month and the day of the week formats are treated specially
# because of a possible ambiguity in some locales where the full
# and abbreviated names are equal or names of different types
# are equal. See doc of __find_month_format for more details.
lst, fmt=self.__find_weekday_format(directive)
iflst:
current_format=current_format.replace(lst[2], fmt, 1)
lst, fmt=self.__find_month_format(directive)
iflst:
current_format=current_format.replace(lst[3], fmt, 1)
ifself.am_pm[1]:
# Must deal with possible lack of locale info
# manifesting itself as the empty string (e.g., Swedish's
# lack of AM/PM info) or a platform returning a tuple of empty
# strings (e.g., MacOS 9 having timezone as ('','')).
current_format=current_format.replace(self.am_pm[1], '%p')
fortz_valuesinself.timezone:
fortzintz_values:
iftz:
current_format=current_format.replace(tz, "%Z")
# Transform all non-ASCII digits to digits in range U+0660 to U+0669.
current_format=re_sub(r'\d(?<![0-9])',
lambdam: chr(0x0660+int(m[0])),
current_format)
forold, newinreplacement_pairs:
current_format=current_format.replace(old, new)
# If %W is used, then Sunday, 2005-01-03 will fall on week 0 since
# 2005-01-03 occurs before the first Monday of the year. Otherwise
# %U is used.
if'00'intime.strftime(directive, time_tuple2):
U_W='%W'
else:
U_W='%U'
current_format=current_format.replace('11', U_W)
date_time.append(current_format)
self.LC_date_time=date_time[0]
self.LC_date=date_time[1]
self.LC_time=date_time[2]

def__find_month_format(self, directive):
"""Find the month format appropriate for the current locale.

 In some locales (for example French and Hebrew), the default month
 used in __calc_date_time has the same name in full and abbreviated
 form. Also, the month name can by accident match other part of the
 representation: the day of the week name (for example in Morisyen)
 or the month number (for example in Japanese). Thus, cycle months
 of the year and find all positions that match the month name for
 each month, If no common positions are found, the representation
 does not use the month name.
 """
full_indices=abbr_indices=None
forminrange(1, 13):
time_tuple=time.struct_time((1999, m, 17, 22, 44, 55, 2, 76, 0))
datetime=time.strftime(directive, time_tuple).lower()
indices=set(_findall(datetime, self.f_month[m]))
iffull_indicesisNone:
full_indices=indices
else:
full_indices&=indices
indices=set(_findall(datetime, self.a_month[m]))
ifabbr_indicesisNone:
abbr_indices=indices
else:
abbr_indices&=indices
ifnotfull_indicesandnotabbr_indices:
returnNone, None
iffull_indices:
returnself.f_month, '%B'
ifabbr_indices:
returnself.a_month, '%b'
returnNone, None

def__find_weekday_format(self, directive):
"""Find the day of the week format appropriate for the current locale.

 Similar to __find_month_format().
 """
full_indices=abbr_indices=None
forwdinrange(7):
time_tuple=time.struct_time((1999, 3, 17, 22, 44, 55, wd, 76, 0))
datetime=time.strftime(directive, time_tuple).lower()
indices=set(_findall(datetime, self.f_weekday[wd]))
iffull_indicesisNone:
full_indices=indices
else:
full_indices&=indices
ifself.f_weekday[wd] !=self.a_weekday[wd]:
indices=set(_findall(datetime, self.a_weekday[wd]))
ifabbr_indicesisNone:
abbr_indices=indices
else:
abbr_indices&=indices
ifnotfull_indicesandnotabbr_indices:
returnNone, None
iffull_indices:
returnself.f_weekday, '%A'
ifabbr_indices:
returnself.a_weekday, '%a'
returnNone, None

def__calc_timezone(self):
# Set self.timezone by using time.tzname.
# Do not worry about possibility of time.tzname[0] == time.tzname[1]
# and time.daylight; handle that in strptime.
try:
time.tzset()
exceptAttributeError:
pass
self.tzname=time.tzname
self.daylight=time.daylight
no_saving=frozenset({"utc", "gmt", self.tzname[0].lower()})
ifself.daylight:
has_saving=frozenset({self.tzname[1].lower()})
else:
has_saving=frozenset()
self.timezone= (no_saving, has_saving)


classTimeRE(dict):
"""Handle conversion from format directives to regexes."""

def__init__(self, locale_time=None):
"""Create keys/values.

 Order of execution is important for dependency reasons.

 """
iflocale_time:
self.locale_time=locale_time
else:
self.locale_time=LocaleTime()
base=super()
mapping= {
# The " [1-9]" part of the regex is to make %c from ANSI C work
'd': r"(?P<d>3[0-1]|[1-2]\d|0[1-9]|[1-9]| [1-9])",
'f': r"(?P<f>[0-9]{1,6})",
'H': r"(?P<H>2[0-3]|[0-1]\d|\d)",
'I': r"(?P<I>1[0-2]|0[1-9]|[1-9]| [1-9])",
'G': r"(?P<G>\d\d\d\d)",
'j': r"(?P<j>36[0-6]|3[0-5]\d|[1-2]\d\d|0[1-9]\d|00[1-9]|[1-9]\d|0[1-9]|[1-9])",
'm': r"(?P<m>1[0-2]|0[1-9]|[1-9])",
'M': r"(?P<M>[0-5]\d|\d)",
'S': r"(?P<S>6[0-1]|[0-5]\d|\d)",
'U': r"(?P<U>5[0-3]|[0-4]\d|\d)",
'w': r"(?P<w>[0-6])",
'u': r"(?P<u>[1-7])",
'V': r"(?P<V>5[0-3]|0[1-9]|[1-4]\d|\d)",
# W is set below by using 'U'
'y': r"(?P<y>\d\d)",
'Y': r"(?P<Y>\d\d\d\d)",
'z': r"(?P<z>[+-]\d\d:?[0-5]\d(:?[0-5]\d(\.\d{1,6})?)?|(?-i:Z))",
'A': self.__seqToRE(self.locale_time.f_weekday, 'A'),
'a': self.__seqToRE(self.locale_time.a_weekday, 'a'),
'B': self.__seqToRE(self.locale_time.f_month[1:], 'B'),
'b': self.__seqToRE(self.locale_time.a_month[1:], 'b'),
'p': self.__seqToRE(self.locale_time.am_pm, 'p'),
'Z': self.__seqToRE((tzfortz_namesinself.locale_time.timezone
fortzintz_names),
'Z'),
'%': '%'}
fordin'dmyHIMS':
mapping['O'+d] =r'(?P<%s>\d\d|\d| \d)'%d
mapping['Ow'] =r'(?P<w>\d)'
mapping['W'] =mapping['U'].replace('U', 'W')
base.__init__(mapping)
base.__setitem__('X', self.pattern(self.locale_time.LC_time))
base.__setitem__('x', self.pattern(self.locale_time.LC_date))
base.__setitem__('c', self.pattern(self.locale_time.LC_date_time))

def__seqToRE(self, to_convert, directive):
"""Convert a list to a regex string for matching a directive.

 Want possible matching values to be from longest to shortest. This
 prevents the possibility of a match occurring for a value that also
 a substring of a larger value that should have matched (e.g., 'abc'
 matching when 'abcdef' should have been the match).

 """
to_convert=sorted(to_convert, key=len, reverse=True)
forvalueinto_convert:
ifvalue!='':
break
else:
return''
regex='|'.join(re_escape(stuff) forstuffinto_convert)
regex='(?P<%s>%s'% (directive, regex)
return'%s)'%regex

defpattern(self, format):
"""Return regex pattern for the format string.

 Need to make sure that any characters that might be interpreted as
 regex syntax are escaped.

 """
# The sub() call escapes all characters that might be misconstrued
# as regex syntax. Cannot use re.escape since we have to deal with
# format directives (%m, etc.).
format=re_sub(r"([\\.^$*+?\(\){}\[\]|])", r"\\\1", format)
format=re_sub(r'\s+', r'\\s+', format)
format=re_sub(r"'", "['\u02bc]", format) # needed for br_FR
year_in_format=False
day_of_month_in_format=False
defrepl(m):
format_char=m[1]
matchformat_char:
case'Y'|'y'|'G':
nonlocalyear_in_format
year_in_format=True
case'd':
nonlocalday_of_month_in_format
day_of_month_in_format=True
returnself[format_char]
format=re_sub(r'%([OE]?\\?.?)', repl, format)
ifday_of_month_in_formatandnotyear_in_format:
importwarnings
warnings.warn("""\
Parsing dates involving a day of month without a year specified is ambiguious
and fails to parse leap day. The default behavior will change in Python 3.15
to either always raise an exception or to use a different default year (TBD).
To avoid trouble, add a specific year to the input & format.
See https://github.com/python/cpython/issues/70647.""",
DeprecationWarning,
skip_file_prefixes=(os.path.dirname(__file__),))
returnformat

defcompile(self, format):
"""Return a compiled re object for the format string."""
returnre_compile(self.pattern(format), IGNORECASE)

_cache_lock=_thread_allocate_lock()
# DO NOT modify _TimeRE_cache or _regex_cache without acquiring the cache lock
# first!
_TimeRE_cache=TimeRE()
_CACHE_MAX_SIZE=5# Max number of regexes stored in _regex_cache
_regex_cache= {}

def_calc_julian_from_U_or_W(year, week_of_year, day_of_week, week_starts_Mon):
"""Calculate the Julian day based on the year, week of the year, and day of
 the week, with week_start_day representing whether the week of the year
 assumes the week starts on Sunday or Monday (6 or 0)."""
first_weekday=datetime_date(year, 1, 1).weekday()
# If we are dealing with the %U directive (week starts on Sunday), it's
# easier to just shift the view to Sunday being the first day of the
# week.
ifnotweek_starts_Mon:
first_weekday= (first_weekday+1) %7
day_of_week= (day_of_week+1) %7
# Need to watch out for a week 0 (when the first day of the year is not
# the same as that specified by %U or %W).
week_0_length= (7-first_weekday) %7
ifweek_of_year==0:
return1+day_of_week-first_weekday
else:
days_to_week=week_0_length+ (7* (week_of_year-1))
return1+days_to_week+day_of_week


def_strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
"""Return a 2-tuple consisting of a time struct and an int containing
 the number of microseconds based on the input string and the
 format string."""

forindex, arginenumerate([data_string, format]):
ifnotisinstance(arg, str):
msg="strptime() argument {} must be str, not {}"
raiseTypeError(msg.format(index, type(arg)))

global_TimeRE_cache, _regex_cache
with_cache_lock:
locale_time=_TimeRE_cache.locale_time
if (_getlang() !=locale_time.langor
time.tzname!=locale_time.tznameor
time.daylight!=locale_time.daylight):
_TimeRE_cache=TimeRE()
_regex_cache.clear()
locale_time=_TimeRE_cache.locale_time
iflen(_regex_cache) >_CACHE_MAX_SIZE:
_regex_cache.clear()
format_regex=_regex_cache.get(format)
ifnotformat_regex:
try:
format_regex=_TimeRE_cache.compile(format)
# KeyError raised when a bad format is found; can be specified as
# \\, in which case it was a stray % but with a space after it
exceptKeyErroraserr:
bad_directive=err.args[0]
delerr
bad_directive=bad_directive.replace('\\s', '')
ifnotbad_directive:
raiseValueError("stray %% in format '%s'"%format) fromNone
bad_directive=bad_directive.replace('\\', '', 1)
raiseValueError("'%s' is a bad directive in format '%s'"%
 (bad_directive, format)) fromNone
_regex_cache[format] =format_regex
found=format_regex.match(data_string)
ifnotfound:
raiseValueError("time data %r does not match format %r"%
 (data_string, format))
iflen(data_string) !=found.end():
raiseValueError("unconverted data remains: %s"%
data_string[found.end():])

iso_year=year=None
month=day=1
hour=minute=second=fraction=0
tz=-1
gmtoff=None
gmtoff_fraction=0
iso_week=week_of_year=None
week_of_year_start=None
# weekday and julian defaulted to None so as to signal need to calculate
# values
weekday=julian=None
found_dict=found.groupdict()
forgroup_keyinfound_dict.keys():
# Directives not explicitly handled below:
# c, x, X
# handled by making out of other directives
# U, W
# worthless without day of the week
ifgroup_key=='y':
year=int(found_dict['y'])
# Open Group specification for strptime() states that a %y
#value in the range of [00, 68] is in the century 2000, while
#[69,99] is in the century 1900
ifyear<=68:
year+=2000
else:
year+=1900
elifgroup_key=='Y':
year=int(found_dict['Y'])
elifgroup_key=='G':
iso_year=int(found_dict['G'])
elifgroup_key=='m':
month=int(found_dict['m'])
elifgroup_key=='B':
month=locale_time.f_month.index(found_dict['B'].lower())
elifgroup_key=='b':
month=locale_time.a_month.index(found_dict['b'].lower())
elifgroup_key=='d':
day=int(found_dict['d'])
elifgroup_key=='H':
hour=int(found_dict['H'])
elifgroup_key=='I':
hour=int(found_dict['I'])
ampm=found_dict.get('p', '').lower()
# If there was no AM/PM indicator, we'll treat this like AM
ifampmin ('', locale_time.am_pm[0]):
# We're in AM so the hour is correct unless we're
# looking at 12 midnight.
# 12 midnight == 12 AM == hour 0
ifhour==12:
hour=0
elifampm==locale_time.am_pm[1]:
# We're in PM so we need to add 12 to the hour unless
# we're looking at 12 noon.
# 12 noon == 12 PM == hour 12
ifhour!=12:
hour+=12
elifgroup_key=='M':
minute=int(found_dict['M'])
elifgroup_key=='S':
second=int(found_dict['S'])
elifgroup_key=='f':
s=found_dict['f']
# Pad to always return microseconds.
s+="0"* (6-len(s))
fraction=int(s)
elifgroup_key=='A':
weekday=locale_time.f_weekday.index(found_dict['A'].lower())
elifgroup_key=='a':
weekday=locale_time.a_weekday.index(found_dict['a'].lower())
elifgroup_key=='w':
weekday=int(found_dict['w'])
ifweekday==0:
weekday=6
else:
weekday-=1
elifgroup_key=='u':
weekday=int(found_dict['u'])
weekday-=1
elifgroup_key=='j':
julian=int(found_dict['j'])
elifgroup_keyin ('U', 'W'):
week_of_year=int(found_dict[group_key])
ifgroup_key=='U':
# U starts week on Sunday.
week_of_year_start=6
else:
# W starts week on Monday.
week_of_year_start=0
elifgroup_key=='V':
iso_week=int(found_dict['V'])
elifgroup_key=='z':
z=found_dict['z']
ifz=='Z':
gmtoff=0
else:
ifz[3] ==':':
z=z[:3] +z[4:]
iflen(z) >5:
ifz[5] !=':':
msg=f"Inconsistent use of : in {found_dict['z']}"
raiseValueError(msg)
z=z[:5] +z[6:]
hours=int(z[1:3])
minutes=int(z[3:5])
seconds=int(z[5:7] or0)
gmtoff= (hours*60*60) + (minutes*60) +seconds
gmtoff_remainder=z[8:]
# Pad to always return microseconds.
gmtoff_remainder_padding="0"* (6-len(gmtoff_remainder))
gmtoff_fraction=int(gmtoff_remainder+gmtoff_remainder_padding)
ifz.startswith("-"):
gmtoff=-gmtoff
gmtoff_fraction=-gmtoff_fraction
elifgroup_key=='Z':
# Since -1 is default value only need to worry about setting tz if
# it can be something other than -1.
found_zone=found_dict['Z'].lower()
forvalue, tz_valuesinenumerate(locale_time.timezone):
iffound_zoneintz_values:
# Deal with bad locale setup where timezone names are the
# same and yet time.daylight is true; too ambiguous to
# be able to tell what timezone has daylight savings
if (time.tzname[0] ==time.tzname[1] and
time.daylightandfound_zonenotin ("utc", "gmt")):
break
else:
tz=value
break

# Deal with the cases where ambiguities arise
# don't assume default values for ISO week/year
ifiso_yearisnotNone:
ifjulianisnotNone:
raiseValueError("Day of the year directive '%j' is not "
"compatible with ISO year directive '%G'. "
"Use '%Y' instead.")
elifiso_weekisNoneorweekdayisNone:
raiseValueError("ISO year directive '%G' must be used with "
"the ISO week directive '%V' and a weekday "
"directive ('%A', '%a', '%w', or '%u').")
elifiso_weekisnotNone:
ifyearisNoneorweekdayisNone:
raiseValueError("ISO week directive '%V' must be used with "
"the ISO year directive '%G' and a weekday "
"directive ('%A', '%a', '%w', or '%u').")
else:
raiseValueError("ISO week directive '%V' is incompatible with "
"the year directive '%Y'. Use the ISO year '%G' "
"instead.")

leap_year_fix=False
ifyearisNone:
ifmonth==2andday==29:
year=1904# 1904 is first leap year of 20th century
leap_year_fix=True
else:
year=1900

# If we know the week of the year and what day of that week, we can figure
# out the Julian day of the year.
ifjulianisNoneandweekdayisnotNone:
ifweek_of_yearisnotNone:
week_starts_Mon=Trueifweek_of_year_start==0elseFalse
julian=_calc_julian_from_U_or_W(year, week_of_year, weekday,
week_starts_Mon)
elifiso_yearisnotNoneandiso_weekisnotNone:
datetime_result=datetime_date.fromisocalendar(iso_year, iso_week, weekday+1)
year=datetime_result.year
month=datetime_result.month
day=datetime_result.day
ifjulianisnotNoneandjulian<=0:
year-=1
yday=366ifcalendar.isleap(year) else365
julian+=yday

ifjulianisNone:
# Cannot pre-calculate datetime_date() since can change in Julian
# calculation and thus could have different value for the day of
# the week calculation.
# Need to add 1 to result since first day of the year is 1, not 0.
julian=datetime_date(year, month, day).toordinal() - \
datetime_date(year, 1, 1).toordinal() +1
else: # Assume that if they bothered to include Julian day (or if it was
# calculated above with year/week/weekday) it will be accurate.
datetime_result=datetime_date.fromordinal(
 (julian-1) +
datetime_date(year, 1, 1).toordinal())
year=datetime_result.year
month=datetime_result.month
day=datetime_result.day
ifweekdayisNone:
weekday=datetime_date(year, month, day).weekday()
# Add timezone info
tzname=found_dict.get("Z")

ifleap_year_fix:
# the caller didn't supply a year but asked for Feb 29th. We couldn't
# use the default of 1900 for computations. We set it back to ensure
# that February 29th is smaller than March 1st.
year=1900

return (year, month, day,
hour, minute, second,
weekday, julian, tz, tzname, gmtoff), fraction, gmtoff_fraction

def_strptime_time(data_string, format="%a %b %d %H:%M:%S %Y"):
"""Return a time struct based on the input string and the
 format string."""
tt=_strptime(data_string, format)[0]
returntime.struct_time(tt[:time._STRUCT_TM_ITEMS])

def_strptime_datetime(cls, data_string, format="%a %b %d %H:%M:%S %Y"):
"""Return a class cls instance based on the input string and the
 format string."""
tt, fraction, gmtoff_fraction=_strptime(data_string, format)
tzname, gmtoff=tt[-2:]
args=tt[:6] + (fraction,)
ifgmtoffisnotNone:
tzdelta=datetime_timedelta(seconds=gmtoff, microseconds=gmtoff_fraction)
iftzname:
tz=datetime_timezone(tzdelta, tzname)
else:
tz=datetime_timezone(tzdelta)
args+= (tz,)

returncls(*args)