452 lines
19 KiB
Python
452 lines
19 KiB
Python
"""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
|
|
try:
|
|
from thread import allocate_lock as _thread_allocate_lock
|
|
except:
|
|
from dummy_thread import allocate_lock as _thread_allocate_lock
|
|
|
|
__author__ = "Brett Cannon"
|
|
__email__ = "brett@python.org"
|
|
|
|
__all__ = ['strptime']
|
|
|
|
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")
|
|
|
|
def __pad(self, seq, front):
|
|
# Add '' to seq to either the front (is True), else the back.
|
|
seq = list(seq)
|
|
if front:
|
|
seq.insert(0, '')
|
|
else:
|
|
seq.append('')
|
|
return seq
|
|
|
|
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 (01,22):
|
|
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] == timetzname[1]
|
|
# and time.daylight; handle that in strptime .
|
|
try:
|
|
time.tzset()
|
|
except AttributeError:
|
|
pass
|
|
no_saving = frozenset(["utc", "gmt", time.tzname[0].lower()])
|
|
if time.daylight:
|
|
has_saving = frozenset([time.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(TimeRE, self)
|
|
base.__init__({
|
|
# The " \d" 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])",
|
|
'H': r"(?P<H>2[0-3]|[0-1]\d|\d)",
|
|
'I': r"(?P<I>1[0-2]|0[1-9]|[1-9])",
|
|
'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])",
|
|
# 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)",
|
|
'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 occuring 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('\s+')
|
|
format = whitespace_replacement.sub('\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 strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
|
|
"""Return a time struct based on the input string and the format string."""
|
|
global _TimeRE_cache, _regex_cache
|
|
_cache_lock.acquire()
|
|
try:
|
|
time_re = _TimeRE_cache
|
|
locale_time = time_re.locale_time
|
|
if _getlang() != locale_time.lang:
|
|
_TimeRE_cache = TimeRE()
|
|
_regex_cache = {}
|
|
if len(_regex_cache) > _CACHE_MAX_SIZE:
|
|
_regex_cache.clear()
|
|
format_regex = _regex_cache.get(format)
|
|
if not format_regex:
|
|
try:
|
|
format_regex = time_re.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, 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))
|
|
# IndexError only occurs when the format string is "%"
|
|
except IndexError:
|
|
raise ValueError("stray %% in format '%s'" % format)
|
|
_regex_cache[format] = format_regex
|
|
finally:
|
|
_cache_lock.release()
|
|
found = format_regex.match(data_string)
|
|
if not found:
|
|
raise ValueError("time data did not match format: data=%s fmt=%s" %
|
|
(data_string, format))
|
|
if len(data_string) != found.end():
|
|
raise ValueError("unconverted data remains: %s" %
|
|
data_string[found.end():])
|
|
year = 1900
|
|
month = day = 1
|
|
hour = minute = second = 0
|
|
tz = -1
|
|
# Default to -1 to signify that values not known; not critical to have,
|
|
# though
|
|
week_of_year = -1
|
|
week_of_year_start = -1
|
|
# weekday and julian defaulted to -1 so as to signal need to calculate
|
|
# values
|
|
weekday = julian = -1
|
|
found_dict = found.groupdict()
|
|
for group_key in found_dict.iterkeys():
|
|
# 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 == '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 == '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 == '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 == '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
|
|
# 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 == -1 and week_of_year != -1 and weekday != -1:
|
|
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)
|
|
# Cannot pre-calculate datetime_date() since can change in Julian
|
|
# calculation and thus could have different value for the day of the week
|
|
# calculation.
|
|
if julian == -1:
|
|
# 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 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 == -1:
|
|
weekday = datetime_date(year, month, day).weekday()
|
|
return time.struct_time((year, month, day,
|
|
hour, minute, second,
|
|
weekday, julian, tz))
|