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"""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 | |
""" | |
import time | |
import locale | |
import calendar | |
from re import compile as re_compile | |
from re import IGNORECASE | |
from re import escape as re_escape | |
from datetime import (date as datetime_date, | |
timedelta as datetime_timedelta, | |
timezone as datetime_timezone) | |
from _thread import allocate_lock as _thread_allocate_lock | |
__all__ = [] | |
def _getlang(): | |
# Figure out what the current language is set to. | |
return locale.getlocale(locale.LC_TIME) | |
class LocaleTime(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: | |
raise ValueError("locale changed during initialization") | |
if time.tzname != self.tzname or time.daylight != self.daylight: | |
raise ValueError("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() for i in range(7)] | |
f_weekday = [calendar.day_name[i].lower() for i in range(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() for i in range(13)] | |
f_month = [calendar.month_name[i].lower() for i in range(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 = [] | |
for hour in (1, 22): | |
time_tuple = time.struct_time((1999,3,17,hour,44,55,2,76,0)) | |
am_pm.append(time.strftime("%p", time_tuple).lower()) | |
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)) | |
date_time = [None, None, None] | |
date_time[0] = time.strftime("%c", time_tuple).lower() | |
date_time[1] = time.strftime("%x", time_tuple).lower() | |
date_time[2] = time.strftime("%X", time_tuple).lower() | |
replacement_pairs = [('%', '%%'), (self.f_weekday[2], '%A'), | |
(self.f_month[3], '%B'), (self.a_weekday[2], '%a'), | |
(self.a_month[3], '%b'), (self.am_pm[1], '%p'), | |
('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')] | |
replacement_pairs.extend([(tz, "%Z") for tz_values in self.timezone | |
for tz in tz_values]) | |
for offset,directive in ((0,'%c'), (1,'%x'), (2,'%X')): | |
current_format = date_time[offset] | |
for old, new in replacement_pairs: | |
# 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 ('','')). | |
if old: | |
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. | |
time_tuple = time.struct_time((1999,1,3,1,1,1,6,3,0)) | |
if '00' in time.strftime(directive, time_tuple): | |
U_W = '%W' | |
else: | |
U_W = '%U' | |
date_time[offset] = current_format.replace('11', U_W) | |
self.LC_date_time = date_time[0] | |
self.LC_date = date_time[1] | |
self.LC_time = date_time[2] | |
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() | |
except AttributeError: | |
pass | |
self.tzname = time.tzname | |
self.daylight = time.daylight | |
no_saving = frozenset({"utc", "gmt", self.tzname[0].lower()}) | |
if self.daylight: | |
has_saving = frozenset({self.tzname[1].lower()}) | |
else: | |
has_saving = frozenset() | |
self.timezone = (no_saving, has_saving) | |
class TimeRE(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. | |
""" | |
if locale_time: | |
self.locale_time = locale_time | |
else: | |
self.locale_time = LocaleTime() | |
base = super() | |
base.__init__({ | |
# 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])", | |
'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)", | |
#XXX: Does 'Y' need to worry about having less or more than | |
# 4 digits? | |
'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((tz for tz_names in self.locale_time.timezone | |
for tz in tz_names), | |
'Z'), | |
'%': '%'}) | |
base.__setitem__('W', base.__getitem__('U').replace('U', 'W')) | |
base.__setitem__('c', self.pattern(self.locale_time.LC_date_time)) | |
base.__setitem__('x', self.pattern(self.locale_time.LC_date)) | |
base.__setitem__('X', self.pattern(self.locale_time.LC_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) | |
for value in to_convert: | |
if value != '': | |
break | |
else: | |
return '' | |
regex = '|'.join(re_escape(stuff) for stuff in to_convert) | |
regex = '(?P<%s>%s' % (directive, regex) | |
return '%s)' % regex | |
def pattern(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. | |
""" | |
processed_format = '' | |
# 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.). | |
regex_chars = re_compile(r"([\\.^$*+?\(\){}\[\]|])") | |
format = regex_chars.sub(r"\\\1", format) | |
whitespace_replacement = re_compile(r'\s+') | |
format = whitespace_replacement.sub(r'\\s+', format) | |
while '%' in format: | |
directive_index = format.index('%')+1 | |
processed_format = "%s%s%s" % (processed_format, | |
format[:directive_index-1], | |
self[format[directive_index]]) | |
format = format[directive_index+1:] | |
return "%s%s" % (processed_format, format) | |
def compile(self, format): | |
"""Return a compiled re object for the format string.""" | |
return re_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. | |
if not week_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 | |
if week_of_year == 0: | |
return 1 + day_of_week - first_weekday | |
else: | |
days_to_week = week_0_length + (7 * (week_of_year - 1)) | |
return 1 + days_to_week + day_of_week | |
def _calc_julian_from_V(iso_year, iso_week, iso_weekday): | |
"""Calculate the Julian day based on the ISO 8601 year, week, and weekday. | |
ISO weeks start on Mondays, with week 01 being the week containing 4 Jan. | |
ISO week days range from 1 (Monday) to 7 (Sunday). | |
""" | |
correction = datetime_date(iso_year, 1, 4).isoweekday() + 3 | |
ordinal = (iso_week * 7) + iso_weekday - correction | |
# ordinal may be negative or 0 now, which means the date is in the previous | |
# calendar year | |
if ordinal < 1: | |
ordinal += datetime_date(iso_year, 1, 1).toordinal() | |
iso_year -= 1 | |
ordinal -= datetime_date(iso_year, 1, 1).toordinal() | |
return iso_year, ordinal | |
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.""" | |
for index, arg in enumerate([data_string, format]): | |
if not isinstance(arg, str): | |
msg = "strptime() argument {} must be str, not {}" | |
raise TypeError(msg.format(index, type(arg))) | |
global _TimeRE_cache, _regex_cache | |
with _cache_lock: | |
locale_time = _TimeRE_cache.locale_time | |
if (_getlang() != locale_time.lang or | |
time.tzname != locale_time.tzname or | |
time.daylight != locale_time.daylight): | |
_TimeRE_cache = TimeRE() | |
_regex_cache.clear() | |
locale_time = _TimeRE_cache.locale_time | |
if len(_regex_cache) > _CACHE_MAX_SIZE: | |
_regex_cache.clear() | |
format_regex = _regex_cache.get(format) | |
if not format_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 | |
except KeyError as err: | |
bad_directive = err.args[0] | |
if bad_directive == "\\": | |
bad_directive = "%" | |
del err | |
raise ValueError("'%s' is a bad directive in format '%s'" % | |
(bad_directive, format)) from None | |
# IndexError only occurs when the format string is "%" | |
except IndexError: | |
raise ValueError("stray %% in format '%s'" % format) from None | |
_regex_cache[format] = format_regex | |
found = format_regex.match(data_string) | |
if not found: | |
raise ValueError("time data %r does not match format %r" % | |
(data_string, format)) | |
if len(data_string) != found.end(): | |
raise ValueError("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 | |
# Default to -1 to signify that values not known; not critical to have, | |
# though | |
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() | |
for group_key in found_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 | |
if group_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 | |
if year <= 68: | |
year += 2000 | |
else: | |
year += 1900 | |
elif group_key == 'Y': | |
year = int(found_dict['Y']) | |
elif group_key == 'G': | |
iso_year = int(found_dict['G']) | |
elif group_key == 'm': | |
month = int(found_dict['m']) | |
elif group_key == 'B': | |
month = locale_time.f_month.index(found_dict['B'].lower()) | |
elif group_key == 'b': | |
month = locale_time.a_month.index(found_dict['b'].lower()) | |
elif group_key == 'd': | |
day = int(found_dict['d']) | |
elif group_key == 'H': | |
hour = int(found_dict['H']) | |
elif group_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 | |
if ampm in ('', 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 | |
if hour == 12: | |
hour = 0 | |
elif ampm == 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 | |
if hour != 12: | |
hour += 12 | |
elif group_key == 'M': | |
minute = int(found_dict['M']) | |
elif group_key == 'S': | |
second = int(found_dict['S']) | |
elif group_key == 'f': | |
s = found_dict['f'] | |
# Pad to always return microseconds. | |
s += "0" * (6 - len(s)) | |
fraction = int(s) | |
elif group_key == 'A': | |
weekday = locale_time.f_weekday.index(found_dict['A'].lower()) | |
elif group_key == 'a': | |
weekday = locale_time.a_weekday.index(found_dict['a'].lower()) | |
elif group_key == 'w': | |
weekday = int(found_dict['w']) | |
if weekday == 0: | |
weekday = 6 | |
else: | |
weekday -= 1 | |
elif group_key == 'u': | |
weekday = int(found_dict['u']) | |
weekday -= 1 | |
elif group_key == 'j': | |
julian = int(found_dict['j']) | |
elif group_key in ('U', 'W'): | |
week_of_year = int(found_dict[group_key]) | |
if group_key == 'U': | |
# U starts week on Sunday. | |
week_of_year_start = 6 | |
else: | |
# W starts week on Monday. | |
week_of_year_start = 0 | |
elif group_key == 'V': | |
iso_week = int(found_dict['V']) | |
elif group_key == 'z': | |
z = found_dict['z'] | |
if z == 'Z': | |
gmtoff = 0 | |
else: | |
if z[3] == ':': | |
z = z[:3] + z[4:] | |
if len(z) > 5: | |
if z[5] != ':': | |
msg = f"Inconsistent use of : in {found_dict['z']}" | |
raise ValueError(msg) | |
z = z[:5] + z[6:] | |
hours = int(z[1:3]) | |
minutes = int(z[3:5]) | |
seconds = int(z[5:7] or 0) | |
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) | |
if z.startswith("-"): | |
gmtoff = -gmtoff | |
gmtoff_fraction = -gmtoff_fraction | |
elif group_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() | |
for value, tz_values in enumerate(locale_time.timezone): | |
if found_zone in tz_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.daylight and found_zone not in ("utc", "gmt")): | |
break | |
else: | |
tz = value | |
break | |
# Deal with the cases where ambiguities arize | |
# don't assume default values for ISO week/year | |
if year is None and iso_year is not None: | |
if iso_week is None or weekday is None: | |
raise ValueError("ISO year directive '%G' must be used with " | |
"the ISO week directive '%V' and a weekday " | |
"directive ('%A', '%a', '%w', or '%u').") | |
if julian is not None: | |
raise ValueError("Day of the year directive '%j' is not " | |
"compatible with ISO year directive '%G'. " | |
"Use '%Y' instead.") | |
elif week_of_year is None and iso_week is not None: | |
if weekday is None: | |
raise ValueError("ISO week directive '%V' must be used with " | |
"the ISO year directive '%G' and a weekday " | |
"directive ('%A', '%a', '%w', or '%u').") | |
else: | |
raise ValueError("ISO week directive '%V' is incompatible with " | |
"the year directive '%Y'. Use the ISO year '%G' " | |
"instead.") | |
leap_year_fix = False | |
if year is None and month == 2 and day == 29: | |
year = 1904 # 1904 is first leap year of 20th century | |
leap_year_fix = True | |
elif year is None: | |
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. | |
if julian is None and weekday is not None: | |
if week_of_year is not None: | |
week_starts_Mon = True if week_of_year_start == 0 else False | |
julian = _calc_julian_from_U_or_W(year, week_of_year, weekday, | |
week_starts_Mon) | |
elif iso_year is not None and iso_week is not None: | |
year, julian = _calc_julian_from_V(iso_year, iso_week, weekday + 1) | |
if julian is not None and julian <= 0: | |
year -= 1 | |
yday = 366 if calendar.isleap(year) else 365 | |
julian += yday | |
if julian is None: | |
# 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 | |
if weekday is None: | |
weekday = datetime_date(year, month, day).weekday() | |
# Add timezone info | |
tzname = found_dict.get("Z") | |
if leap_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] | |
return time.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,) | |
if gmtoff is not None: | |
tzdelta = datetime_timedelta(seconds=gmtoff, microseconds=gmtoff_fraction) | |
if tzname: | |
tz = datetime_timezone(tzdelta, tzname) | |
else: | |
tz = datetime_timezone(tzdelta) | |
args += (tz,) | |
return cls(*args) | |