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561 lines
22 KiB
Python
561 lines
22 KiB
Python
"""Strptime-related classes and functions.
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CLASSES:
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LocaleTime -- Discovers and/or stores locale-specific time information
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TimeRE -- Creates regexes for pattern matching a string of text containing
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time information as is returned by time.strftime()
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FUNCTIONS:
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firstjulian -- Calculates the Julian date up to the first of the specified
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year
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gregorian -- Calculates the Gregorian date based on the Julian day and
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year
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julianday -- Calculates the Julian day since the first of the year based
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on the Gregorian date
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dayofweek -- Calculates the day of the week from the Gregorian date.
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strptime -- Calculates the time struct represented by the passed-in string
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Requires Python 2.2.1 or higher.
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Can be used in Python 2.2 if the following line is added:
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>>> True = 1; False = 0
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"""
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import time
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import locale
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import calendar
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from re import compile as re_compile
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from re import IGNORECASE
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__author__ = "Brett Cannon"
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__email__ = "drifty@bigfoot.com"
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__all__ = ['strptime']
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RegexpType = type(re_compile(''))
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def _getlang():
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# Figure out what the current language is set to.
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current_lang = locale.getlocale(locale.LC_TIME)[0]
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if current_lang:
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return current_lang
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else:
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current_lang = locale.getdefaultlocale()[0]
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if current_lang:
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return current_lang
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else:
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return ''
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class LocaleTime(object):
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"""Stores and handles locale-specific information related to time.
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ATTRIBUTES (all read-only after instance creation! Instance variables that
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store the values have mangled names):
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f_weekday -- full weekday names (7-item list)
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a_weekday -- abbreviated weekday names (7-item list)
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f_month -- full weekday names (14-item list; dummy value in [0], which
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is added by code)
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a_month -- abbreviated weekday names (13-item list, dummy value in
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[0], which is added by code)
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am_pm -- AM/PM representation (2-item list)
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LC_date_time -- format string for date/time representation (string)
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LC_date -- format string for date representation (string)
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LC_time -- format string for time representation (string)
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timezone -- daylight- and non-daylight-savings timezone representation
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(3-item list; code tacks on blank item at end for
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possible lack of timezone such as UTC)
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lang -- Language used by instance (string)
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"""
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def __init__(self, f_weekday=None, a_weekday=None, f_month=None,
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a_month=None, am_pm=None, LC_date_time=None, LC_time=None,
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LC_date=None, timezone=None, lang=None):
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"""Optionally set attributes with passed-in values."""
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if f_weekday is None:
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self.__f_weekday = None
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elif len(f_weekday) == 7:
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self.__f_weekday = list(f_weekday)
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else:
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raise TypeError("full weekday names must be a 7-item sequence")
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if a_weekday is None:
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self.__a_weekday = None
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elif len(a_weekday) == 7:
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self.__a_weekday = list(a_weekday)
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else:
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raise TypeError(
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"abbreviated weekday names must be a 7-item sequence")
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if f_month is None:
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self.__f_month = None
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elif len(f_month) == 12:
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self.__f_month = self.__pad(f_month, True)
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else:
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raise TypeError("full month names must be a 12-item sequence")
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if a_month is None:
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self.__a_month = None
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elif len(a_month) == 12:
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self.__a_month = self.__pad(a_month, True)
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else:
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raise TypeError(
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"abbreviated month names must be a 12-item sequence")
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if am_pm is None:
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self.__am_pm = None
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elif len(am_pm) == 2:
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self.__am_pm = am_pm
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else:
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raise TypeError("AM/PM representation must be a 2-item sequence")
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self.__LC_date_time = LC_date_time
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self.__LC_time = LC_time
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self.__LC_date = LC_date
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self.__timezone = timezone
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if timezone:
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if len(timezone) != 2:
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raise TypeError("timezone names must contain 2 items")
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else:
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self.__timezone = self.__pad(timezone, False)
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self.__lang = lang
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def __pad(self, seq, front):
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# Add '' to seq to either front (is True), else the back.
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seq = list(seq)
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if front:
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seq.insert(0, '')
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else:
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seq.append('')
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return seq
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def __set_nothing(self, stuff):
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# Raise TypeError when trying to set an attribute.
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raise TypeError("attribute does not support assignment")
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def __get_f_weekday(self):
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# Fetch self.f_weekday.
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if not self.__f_weekday:
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self.__calc_weekday()
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return self.__f_weekday
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def __get_a_weekday(self):
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# Fetch self.a_weekday.
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if not self.__a_weekday:
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self.__calc_weekday()
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return self.__a_weekday
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f_weekday = property(__get_f_weekday, __set_nothing,
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doc="Full weekday names")
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a_weekday = property(__get_a_weekday, __set_nothing,
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doc="Abbreviated weekday names")
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def __get_f_month(self):
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# Fetch self.f_month.
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if not self.__f_month:
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self.__calc_month()
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return self.__f_month
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def __get_a_month(self):
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# Fetch self.a_month.
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if not self.__a_month:
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self.__calc_month()
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return self.__a_month
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f_month = property(__get_f_month, __set_nothing,
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doc="Full month names (dummy value at index 0)")
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a_month = property(__get_a_month, __set_nothing,
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doc="Abbreviated month names (dummy value at index 0)")
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def __get_am_pm(self):
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# Fetch self.am_pm.
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if not self.__am_pm:
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self.__calc_am_pm()
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return self.__am_pm
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am_pm = property(__get_am_pm, __set_nothing, doc="AM/PM representation")
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def __get_timezone(self):
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# Fetch self.timezone.
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if not self.__timezone:
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self.__calc_timezone()
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return self.__timezone
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timezone = property(__get_timezone, __set_nothing,
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doc="Timezone representation (dummy value at index 2)")
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def __get_LC_date_time(self):
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# Fetch self.LC_date_time.
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if not self.__LC_date_time:
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self.__calc_date_time()
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return self.__LC_date_time
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def __get_LC_date(self):
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# Fetch self.LC_date.
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if not self.__LC_date:
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self.__calc_date_time()
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return self.__LC_date
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def __get_LC_time(self):
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# Fetch self.LC_time.
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if not self.__LC_time:
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self.__calc_date_time()
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return self.__LC_time
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LC_date_time = property(
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__get_LC_date_time, __set_nothing,
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doc=
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"Format string for locale's date/time representation ('%c' format)")
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LC_date = property(__get_LC_date, __set_nothing,
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doc="Format string for locale's date representation ('%x' format)")
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LC_time = property(__get_LC_time, __set_nothing,
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doc="Format string for locale's time representation ('%X' format)")
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def __get_lang(self):
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# Fetch self.lang.
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if not self.__lang:
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self.__calc_lang()
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return self.__lang
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lang = property(__get_lang, __set_nothing,
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doc="Language used for instance")
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def __calc_weekday(self):
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# Set self.__a_weekday and self.__f_weekday using the calendar
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# module.
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a_weekday = [calendar.day_abbr[i] for i in range(7)]
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f_weekday = [calendar.day_name[i] for i in range(7)]
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if not self.__a_weekday:
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self.__a_weekday = a_weekday
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if not self.__f_weekday:
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self.__f_weekday = f_weekday
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def __calc_month(self):
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# Set self.__f_month and self.__a_month using the calendar module.
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a_month = [calendar.month_abbr[i] for i in range(13)]
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f_month = [calendar.month_name[i] for i in range(13)]
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if not self.__a_month:
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self.__a_month = a_month
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if not self.__f_month:
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self.__f_month = f_month
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def __calc_am_pm(self):
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# Set self.__am_pm by using time.strftime().
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# The magic date (1999,3,17,hour,44,55,2,76,0) is not really that
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# magical; just happened to have used it everywhere else where a
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# static date was needed.
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am_pm = []
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for hour in (01,22):
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time_tuple = time.struct_time((1999,3,17,hour,44,55,2,76,0))
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am_pm.append(time.strftime("%p", time_tuple))
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self.__am_pm = am_pm
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def __calc_date_time(self):
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# Set self.__date_time, self.__date, & self.__time by using
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# time.strftime().
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# Use (1999,3,17,22,44,55,2,76,0) for magic date because the amount of
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# overloaded numbers is minimized. The order in which searches for
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# values within the format string is very important; it eliminates
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# possible ambiguity for what something represents.
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time_tuple = time.struct_time((1999,3,17,22,44,55,2,76,0))
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date_time = [None, None, None]
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date_time[0] = time.strftime("%c", time_tuple)
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date_time[1] = time.strftime("%x", time_tuple)
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date_time[2] = time.strftime("%X", time_tuple)
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for offset,directive in ((0,'%c'), (1,'%x'), (2,'%X')):
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current_format = date_time[offset]
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for old, new in (
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('%', '%%'), (self.f_weekday[2], '%A'),
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(self.f_month[3], '%B'), (self.a_weekday[2], '%a'),
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(self.a_month[3], '%b'), (self.am_pm[1], '%p'),
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(self.timezone[0], '%Z'), (self.timezone[1], '%Z'),
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('1999', '%Y'), ('99', '%y'), ('22', '%H'),
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('44', '%M'), ('55', '%S'), ('76', '%j'),
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('17', '%d'), ('03', '%m'), ('3', '%m'),
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# '3' needed for when no leading zero.
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('2', '%w'), ('10', '%I')):
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# Must deal with possible lack of locale info
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# manifesting itself as the empty string (e.g., Swedish's
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# lack of AM/PM info) or a platform returning a tuple of empty
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# strings (e.g., MacOS 9 having timezone as ('','')).
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if old:
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current_format = current_format.replace(old, new)
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time_tuple = time.struct_time((1999,1,3,1,1,1,6,3,0))
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if time.strftime(directive, time_tuple).find('00'):
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U_W = '%U'
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else:
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U_W = '%W'
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date_time[offset] = current_format.replace('11', U_W)
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if not self.__LC_date_time:
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self.__LC_date_time = date_time[0]
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if not self.__LC_date:
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self.__LC_date = date_time[1]
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if not self.__LC_time:
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self.__LC_time = date_time[2]
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def __calc_timezone(self):
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# Set self.__timezone by using time.tzname.
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#
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# Empty string used for matching when timezone is not used/needed such
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# as with UTC.
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self.__timezone = self.__pad(time.tzname, 0)
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def __calc_lang(self):
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# Set self.__lang by using __getlang().
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self.__lang = _getlang()
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class TimeRE(dict):
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"""Handle conversion from format directives to regexes."""
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def __init__(self, locale_time=LocaleTime()):
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"""Init inst with non-locale regexes and store LocaleTime object."""
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#XXX: Does 'Y' need to worry about having less or more than 4 digits?
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base = super(TimeRE, self)
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base.__init__({
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# The " \d" option is to make %c from ANSI C work
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'd': r"(?P<d>3[0-1]|[1-2]\d|0[1-9]|[1-9]| [1-9])",
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'H': r"(?P<H>2[0-3]|[0-1]\d|\d)",
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'I': r"(?P<I>1[0-2]|0[1-9]|[1-9])",
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'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])",
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'm': r"(?P<m>1[0-2]|0[1-9]|[1-9])",
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'M': r"(?P<M>[0-5]\d|\d)",
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'S': r"(?P<S>6[0-1]|[0-5]\d|\d)",
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'U': r"(?P<U>5[0-3]|[0-4]\d|\d)",
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'w': r"(?P<w>[0-6])",
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# W is set below by using 'U'
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'y': r"(?P<y>\d\d)",
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'Y': r"(?P<Y>\d\d\d\d)"})
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base.__setitem__('W', base.__getitem__('U'))
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self.locale_time = locale_time
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def __getitem__(self, fetch):
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"""Try to fetch regex; if it does not exist, construct it."""
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try:
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return super(TimeRE, self).__getitem__(fetch)
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except KeyError:
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constructors = {
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'A': lambda: self.__seqToRE(self.locale_time.f_weekday, fetch),
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'a': lambda: self.__seqToRE(self.locale_time.a_weekday, fetch),
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'B': lambda: self.__seqToRE(self.locale_time.f_month[1:],
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fetch),
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'b': lambda: self.__seqToRE(self.locale_time.a_month[1:],
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fetch),
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'c': lambda: self.pattern(self.locale_time.LC_date_time),
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'p': lambda: self.__seqToRE(self.locale_time.am_pm, fetch),
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'x': lambda: self.pattern(self.locale_time.LC_date),
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'X': lambda: self.pattern(self.locale_time.LC_time),
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'Z': lambda: self.__seqToRE(self.locale_time.timezone, fetch),
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'%': lambda: '%',
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}
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if fetch in constructors:
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self[fetch] = constructors[fetch]()
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return self[fetch]
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else:
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raise
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def __seqToRE(self, to_convert, directive):
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"""Convert a list to a regex string for matching a directive."""
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def sorter(a, b):
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"""Sort based on length.
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Done in case for some strange reason that names in the locale only
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differ by a suffix and thus want the name with the suffix to match
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first.
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"""
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try:
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a_length = len(a)
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except TypeError:
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a_length = 0
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try:
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b_length = len(b)
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except TypeError:
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b_length = 0
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return cmp(b_length, a_length)
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to_convert = to_convert[:] # Don't want to change value in-place.
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for value in to_convert:
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if value != '':
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break
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else:
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return ''
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to_convert.sort(sorter)
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regex = '|'.join(to_convert)
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regex = '(?P<%s>%s' % (directive, regex)
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return '%s)' % regex
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def pattern(self, format):
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"""Return re pattern for the format string."""
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processed_format = ''
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whitespace_replacement = re_compile('\s+')
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format = whitespace_replacement.sub('\s*', format)
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while format.find('%') != -1:
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directive_index = format.index('%')+1
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processed_format = "%s%s%s" % (processed_format,
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format[:directive_index-1],
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self[format[directive_index]])
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format = format[directive_index+1:]
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return "%s%s" % (processed_format, format)
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def compile(self, format):
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"""Return a compiled re object for the format string."""
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return re_compile(self.pattern(format), IGNORECASE)
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# Cached TimeRE; probably only need one instance ever so cache it for performance
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_locale_cache = TimeRE()
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# Cached regex objects; same reason as for TimeRE cache
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_regex_cache = dict()
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def strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
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"""Return a time struct based on the input data and the format string."""
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global _locale_cache
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global _regex_cache
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locale_time = _locale_cache.locale_time
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# If the language changes, caches are invalidated, so clear them
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if locale_time.lang != _getlang():
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_locale_cache = TimeRE()
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_regex_cache.clear()
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format_regex = _regex_cache.get(format)
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if not format_regex:
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# Limit regex cache size to prevent major bloating of the module;
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# The value 5 is arbitrary
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if len(_regex_cache) > 5:
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_regex_cache.clear()
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format_regex = _locale_cache.compile(format)
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_regex_cache[format] = format_regex
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found = format_regex.match(data_string)
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if not found:
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raise ValueError("time data did not match format")
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year = 1900
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month = day = 1
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hour = minute = second = 0
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tz = -1
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# Defaulted to -1 so as to signal using functions to calc values
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weekday = julian = -1
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found_dict = found.groupdict()
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for group_key in found_dict.iterkeys():
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if group_key == 'y':
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year = int(found_dict['y'])
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# Open Group specification for strptime() states that a %y
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#value in the range of [00, 68] is in the century 2000, while
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#[69,99] is in the century 1900
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if year <= 68:
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year += 2000
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else:
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year += 1900
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elif group_key == 'Y':
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year = int(found_dict['Y'])
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elif group_key == 'm':
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month = int(found_dict['m'])
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elif group_key == 'B':
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month = _insensitiveindex(locale_time.f_month, found_dict['B'])
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elif group_key == 'b':
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month = _insensitiveindex(locale_time.a_month, found_dict['b'])
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elif group_key == 'd':
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day = int(found_dict['d'])
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elif group_key is 'H':
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hour = int(found_dict['H'])
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elif group_key == 'I':
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hour = int(found_dict['I'])
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ampm = found_dict.get('p', '').lower()
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# If there was no AM/PM indicator, we'll treat this like AM
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if ampm in ('', locale_time.am_pm[0].lower()):
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# We're in AM so the hour is correct unless we're
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# looking at 12 midnight.
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# 12 midnight == 12 AM == hour 0
|
|
if hour == 12:
|
|
hour = 0
|
|
elif ampm == locale_time.am_pm[1].lower():
|
|
# 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 = _insensitiveindex(locale_time.f_weekday,
|
|
found_dict['A'])
|
|
elif group_key == 'a':
|
|
weekday = _insensitiveindex(locale_time.a_weekday,
|
|
found_dict['a'])
|
|
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 == 'Z':
|
|
found_zone = found_dict['Z'].lower()
|
|
if locale_time.timezone[0] == locale_time.timezone[1]:
|
|
pass #Deals with bad locale setup where timezone info is
|
|
# the same; first found on FreeBSD 4.4.
|
|
elif locale_time.timezone[0].lower() == found_zone:
|
|
tz = 0
|
|
elif locale_time.timezone[1].lower() == found_zone:
|
|
tz = 1
|
|
elif locale_time.timezone[2].lower() == found_zone:
|
|
tz = -1
|
|
#XXX <bc>: If calculating fxns are never exposed to the general
|
|
#populous then just inline calculations. Also might be able to use
|
|
#``datetime`` and the methods it provides.
|
|
if julian == -1:
|
|
julian = julianday(year, month, day)
|
|
else: # Assuming that if they bothered to include Julian day it will
|
|
#be accurate
|
|
year, month, day = gregorian(julian, year)
|
|
if weekday == -1:
|
|
weekday = dayofweek(year, month, day)
|
|
return time.struct_time((year, month, day,
|
|
hour, minute, second,
|
|
weekday, julian, tz))
|
|
|
|
def _insensitiveindex(lst, findme):
|
|
# Perform a case-insensitive index search.
|
|
|
|
#XXX <bc>: If LocaleTime is not exposed, then consider removing this and
|
|
# just lowercase when LocaleTime sets its vars and lowercasing
|
|
# search values.
|
|
findme = findme.lower()
|
|
for key,item in enumerate(lst):
|
|
if item.lower() == findme:
|
|
return key
|
|
else:
|
|
raise ValueError("value not in list")
|
|
|
|
def firstjulian(year):
|
|
"""Calculate the Julian date up until the first of the year."""
|
|
return ((146097 * (year + 4799)) // 400) - 31738
|
|
|
|
def julianday(year, month, day):
|
|
"""Calculate the Julian day since the beginning of the year.
|
|
Calculated from the Gregorian date.
|
|
"""
|
|
a = (14 - month) // 12
|
|
return (day - 32045
|
|
+ (((153 * (month + (12 * a) - 3)) + 2) // 5)
|
|
+ ((146097 * (year + 4800 - a)) // 400)) - firstjulian(year) + 1
|
|
|
|
def gregorian(julian, year):
|
|
"""Return 3-item list containing Gregorian date based on the Julian day."""
|
|
a = 32043 + julian + firstjulian(year)
|
|
b = ((4 * a) + 3) // 146097
|
|
c = a - ((146097 * b) // 4)
|
|
d = ((4 * c) + 3) // 1461
|
|
e = c - ((1461 * d) // 4)
|
|
m = ((5 * e) + 2) // 153
|
|
day = 1 + e - (((153 * m) + 2) // 5)
|
|
month = m + 3 - (12 * (m // 10))
|
|
year = (100 * b) + d - 4800 + (m // 10)
|
|
return [year, month, day]
|
|
|
|
def dayofweek(year, month, day):
|
|
"""Calculate the day of the week (Monday is 0)."""
|
|
a = (14 - month) // 12
|
|
y = year - a
|
|
weekday = (day + y + ((97 * y) // 400)
|
|
+ ((31 * (month + (12 * a) -2 )) // 12)) % 7
|
|
if weekday == 0:
|
|
return 6
|
|
else:
|
|
return weekday-1
|