Pure Python strptime implementation by Brett Cannon. See SF patch 474274.

Also adds tests.

1 files changed, 488 insertions, 0 deletions

diff --git a/Lib/_strptime.py b/Lib/_strptime.py
new file mode 100644
index 0000000..cde6e5f
--- /dev/null
+++ b/Lib/_strptime.py
@@ -0,0 +1,488 @@
+"""Strptime-related classes and functions.
+
+CLASSES:
+    LocaleTime -- Discovers and/or stores locale-specific time information
+    TimeRE -- Creates regexes for pattern matching string of text containing 
+                time information as is returned by time.strftime()
+
+FUNCTIONS:
+    firstjulian -- Calculates the Julian date up to the first of the specified
+                    year
+    gregorian -- Calculates the Gregorian date based on the Julian day and
+                    year
+    julianday -- Calculates the Julian day since the first of the year based 
+                    on the Gregorian date
+    dayofweek -- Calculates the day of the week from the Gregorian date.
+    strptime -- Calculates the time struct represented by the passed-in string
+
+Requires Python 2.2.1 or higher.
+Can be used in Python 2.2 if the following line is added:
+    >>> True = 1; False = 0
+
+"""
+import time
+import locale
+import calendar
+from re import compile as re_compile
+from re import IGNORECASE
+from string import whitespace as whitespace_string
+
+__version__ = (2,1,5)
+__author__ = "Brett Cannon"
+__email__ = "drifty@bigfoot.com"
+
+__all__ = ['strptime']
+
+class LocaleTime(object):
+    """Stores and handles locale-specific information related to time.
+
+    ATTRIBUTES (all read-only after instance creation! Instance variables that
+                store the values have mangled names):
+        f_weekday -- full weekday names (7-item list)
+        a_weekday -- abbreviated weekday names (7-item list)
+        f_month -- full weekday names (14-item list; dummy value in [0], which 
+                    is added by code)
+        a_month -- abbreviated weekday 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 
+                    (3-item list; code tacks on blank item at end for 
+                    possible lack of timezone such as UTC)
+        lang -- Language used by instance (string)
+    
+    """
+
+    def __init__(self, f_weekday=None, a_weekday=None, f_month=None, 
+    a_month=None, am_pm=None, LC_date_time=None, LC_time=None, LC_date=None, 
+    timezone=None, lang=None):
+        """Optionally set attributes with passed-in values."""
+        if f_weekday is None: self.__f_weekday = None
+        elif len(f_weekday) == 7: self.__f_weekday = list(f_weekday)
+        else:
+            raise TypeError("full weekday names must be a 7-item sequence")
+        if a_weekday is None: self.__a_weekday = None
+        elif len(a_weekday) == 7: self.__a_weekday = list(a_weekday)
+        else:
+            raise TypeError(
+                    "abbreviated weekday names must be a 7-item  sequence")
+        if f_month is None: self.__f_month = None
+        elif len(f_month) == 12:
+            self.__f_month = self.__pad(f_month, True)
+        else:
+            raise TypeError("full month names must be a 12-item sequence")
+        if a_month is None: self.__a_month = None
+        elif len(a_month) == 12:
+            self.__a_month = self.__pad(a_month, True)
+        else:
+            raise TypeError(
+                        "abbreviated month names must be a 12-item sequence")
+        if am_pm is None:
+            self.__am_pm = None
+        elif len(am_pm) == 2:
+            self.__am_pm = am_pm
+        else:
+            raise TypeError("AM/PM representation must be a 2-item sequence")
+        self.__LC_date_time = LC_date_time
+        self.__LC_time = LC_time
+        self.__LC_date = LC_date
+        self.__timezone = timezone
+        if timezone:
+            if len(timezone) != 2:
+                raise TypeError("timezone names must contain 2 items")
+            else:
+                self.__timezone = self.__pad(timezone, False)
+        self.__lang = lang
+
+    def __pad(self, seq, front):
+        """Add '' to seq to either front (is True), else the back."""
+        seq = list(seq)
+        if front: seq.insert(0, '')
+        else: seq.append('')
+        return seq
+
+    def __set_nothing(self, stuff):
+        """Raise TypeError when trying to set an attribute."""
+        raise TypeError("attribute does not support assignment")
+
+    def __get_f_weekday(self):
+        """Fetch self.f_weekday."""
+        if not self.__f_weekday: self.__calc_weekday()
+        return self.__f_weekday
+
+    def __get_a_weekday(self):
+        """Fetch self.a_weekday."""
+        if not self.__a_weekday: self.__calc_weekday()
+        return self.__a_weekday
+
+    f_weekday = property(__get_f_weekday, __set_nothing, 
+                        doc="Full weekday names")
+    a_weekday = property(__get_a_weekday, __set_nothing, 
+                        doc="Abbreviated weekday names")
+
+    def __get_f_month(self):
+        """Fetch self.f_month."""
+        if not self.__f_month: self.__calc_month()
+        return self.__f_month
+
+    def __get_a_month(self):
+        """Fetch self.a_month."""
+        if not self.__a_month: self.__calc_month()
+        return self.__a_month
+
+    f_month = property(__get_f_month, __set_nothing,
+                        doc="Full month names (dummy value at index 0)")
+    a_month = property(__get_a_month, __set_nothing,
+                        doc="Abbreviated month names (dummy value at index 0)")
+
+    def __get_am_pm(self):
+        """Fetch self.am_pm."""
+        if not self.__am_pm: self.__calc_am_pm()
+        return self.__am_pm
+
+    am_pm = property(__get_am_pm, __set_nothing, doc="AM/PM representation")
+
+    def __get_timezone(self):
+        """Fetch self.timezone."""
+        if not self.__timezone: self.__calc_timezone()
+        return self.__timezone
+
+    timezone = property(__get_timezone, __set_nothing,
+                        doc="Timezone representation (dummy value at index 2)")
+
+    def __get_LC_date_time(self):
+        """Fetch self.LC_date_time."""
+        if not self.__LC_date_time: self.__calc_date_time()
+        return self.__LC_date_time
+
+    def __get_LC_date(self):
+        """Fetch self.LC_date."""
+        if not self.__LC_date: self.__calc_date_time()
+        return self.__LC_date
+
+    def __get_LC_time(self):
+        """Fetch self.LC_time."""
+        if not self.__LC_time: self.__calc_date_time()
+        return self.__LC_time
+
+    LC_date_time = property(__get_LC_date_time, __set_nothing,
+        doc="Format string for locale's date/time representation ('%c' format)")
+    LC_date = property(__get_LC_date, __set_nothing,
+        doc="Format string for locale's date representation ('%x' format)")
+    LC_time = property(__get_LC_time, __set_nothing,
+        doc="Format string for locale's time representation ('%X' format)")
+
+    def __get_lang(self):
+        """Fetch self.lang."""
+        if not self.__lang: self.__calc_lang()
+        return self.__lang
+
+    lang = property(__get_lang, __set_nothing, doc="Language used for instance")
+
+    def __calc_weekday(self):
+        """Set self.__a_weekday and self.__f_weekday using the calendar module."""
+        a_weekday = [calendar.day_abbr[i] for i in range(7)]
+        f_weekday = [calendar.day_name[i] for i in range(7)]
+        if not self.__a_weekday: self.__a_weekday = a_weekday
+        if not self.__f_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] for i in range(13)]
+        f_month = [calendar.month_name[i] for i in range(13)]
+        if not self.__a_month: self.__a_month = a_month
+        if not self.__f_month: self.__f_month = f_month
+
+    def __calc_am_pm(self):
+        """Set self.__am_pm by using time.strftime().
+        
+        The magic date (2002, 3, 17, hour, 44, 44, 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))
+        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)
+        date_time[1] = time.strftime("%x", time_tuple)
+        date_time[2] = time.strftime("%X", time_tuple)
+        for offset,directive in ((0,'%c'), (1,'%x'), (2,'%X')):
+            current_format = date_time[offset]
+            current_format = current_format.replace('%', '%%')
+            current_format = current_format.replace(self.f_weekday[2], '%A')
+            current_format = current_format.replace(self.f_month[3], '%B')
+            current_format = current_format.replace(self.a_weekday[2], '%a')
+            current_format = current_format.replace(self.a_month[3], '%b')
+            current_format = current_format.replace(self.am_pm[1], '%p')
+            current_format = current_format.replace(self.timezone[0], '%Z')
+            current_format = current_format.replace(self.timezone[1], '%Z')
+            current_format = current_format.replace('1999', '%Y')
+            current_format = current_format.replace('99', '%y')
+            current_format = current_format.replace('22', '%H')
+            current_format = current_format.replace('44', '%M')
+            current_format = current_format.replace('55', '%S')
+            current_format = current_format.replace('76', '%j')
+            current_format = current_format.replace('17', '%d')
+            current_format = current_format.replace('03', '%m')
+            current_format = current_format.replace('2', '%w')
+            current_format = current_format.replace('10', '%I')
+            time_tuple = time.struct_time((1999,1,3,1,1,1,6,3,0))
+            if time.strftime(directive, time_tuple).find('00'):
+                U_W = '%U'
+            else:
+                U_W = '%W'
+            date_time[offset] = current_format.replace('11', U_W)
+        if not self.__LC_date_time: self.__LC_date_time = date_time[0]
+        if not self.__LC_date: self.__LC_date = date_time[1]
+        if not self.__LC_time: self.__LC_time = date_time[2]
+
+    def __calc_timezone(self):
+        """Set self.__timezone by using time.tzname.
+        
+        Empty string used for matching when timezone is not used/needed such 
+        as with UTC.
+
+        """
+        self.__timezone = self.__pad(time.tzname, 0)
+
+    def __calc_lang(self):
+        """Set self.lang by using locale.getlocale() or 
+        locale.getdefaultlocale().
+        
+        """
+        current_lang = locale.getlocale(locale.LC_TIME)[0]
+        if current_lang: self.__lang = current_lang
+        else: self.__lang = locale.getdefaultlocale()[0]
+
+class TimeRE(dict):
+    """Handle conversion from format directives to regexes."""
+
+    def __init__(self, locale_time=LocaleTime()):
+        """Initialize instance with non-locale regexes and store LocaleTime object."""
+        super(TimeRE,self).__init__({
+            'd': r"(?P<d>3[0-1]|[0-2]\d|\d| \d)",  #The " \d" option is 
+                                                         #to make %c from ANSI
+                                                         #C work
+            'H': r"(?P<H>2[0-3]|[0-1]\d|\d)",
+            'I': r"(?P<I>0\d|1[0-2]|\d)",
+            'j': r"(?P<j>(?:3[0-5]\d|6[0-6])|[0-2]\d\d|\d)",
+            'm': r"(?P<m>0\d|1[0-2]|\d)",
+            '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': r"(?P<W>5[0-3]|[0-4]\d|\d)",  #Same as U
+            'y': r"(?P<y>\d\d)",
+            'Y': r"(?P<Y>\d\d\d\d)"})
+        self.locale_time = locale_time
+
+    def __getitem__(self, fetch):
+        """Try to fetch regex; if it does not exist, construct it."""
+        try:
+            return super(TimeRE,self).__getitem__(fetch)
+        except KeyError:
+            if fetch == 'A':
+                self[fetch] = self.__seqToRE(self.locale_time.f_weekday, 
+                                                fetch)
+            elif fetch == 'a':
+                self[fetch] = self.__seqToRE(self.locale_time.a_weekday, 
+                                                fetch)
+            elif fetch == 'B':
+                self[fetch] = self.__seqToRE(self.locale_time.f_month[1:], 
+                                                fetch)
+            elif fetch == 'b':
+                self[fetch] = self.__seqToRE(self.locale_time.a_month[1:], 
+                                                fetch)
+            elif fetch == 'c':
+                self[fetch] = self.pattern(self.locale_time.LC_date_time)
+            elif fetch == 'p':
+                self[fetch] = self.__seqToRE(self.locale_time.am_pm, fetch)
+            elif fetch == 'x':
+                self[fetch] = self.pattern(self.locale_time.LC_date)
+            elif fetch == 'X':
+                self[fetch] = self.pattern(self.locale_time.LC_time)
+            elif fetch == 'Z':
+                self[fetch] = self.__seqToRE(self.locale_time.timezone, 
+                                                fetch)
+            elif fetch == '%':
+                return '%'
+            return super(TimeRE,self).__getitem__(fetch)
+        
+    def __seqToRE(self, to_convert, directive):
+        """Convert a list to a regex string for matching directive."""
+        def sorter(a, b):
+            """Sort based on length.
+            
+            Done in case for some strange reason that names in the locale only
+            differ by a suffix and thus want the name with the suffix to match
+            first.
+            
+            """
+            try: a_length = len(a)
+            except TypeError: a_length = 0
+            try: b_length = len(b)
+            except TypeError: b_length = 0
+            return cmp(b_length, a_length)
+        
+        to_convert = to_convert[:]  #Don't want to change value in-place.
+        to_convert.sort(sorter)
+        regex = '(?P<%s>' % directive
+        for item in to_convert:
+            regex = "%s(?:%s)|" % (regex, item)
+        else:
+            regex = regex[:-1]
+        return '%s)' % regex
+
+    def pattern(self, format):
+        """Return re pattern for the format string."""
+        processed_format = ''
+        for whitespace in whitespace_string:
+            format = format.replace(whitespace, r'\s*')
+        while format.find('%') != -1:
+            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."""
+        format = "(?#%s)%s" % (self.locale_time.lang,format)
+        return re_compile(self.pattern(format), IGNORECASE)
+
+
+def strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
+    """Convert data_string to a time struct based on the format string or re object; will return an re object for format if data_string is False.
+    
+    The object passed in for format may either be a re object compiled by 
+    strptime() or a format string.  If False is passed in for data_string 
+    then an re object for format will be returned.  The re object 
+    must be used with the same language as used to compile the re object.
+    
+    """
+    locale_time = LocaleTime()
+    if isinstance(format, type(re_compile(''))):
+        if format.pattern.find(locale_time.lang) == -1:
+            raise TypeError("re object not created with same language as \
+            LocaleTime instance")
+        else:
+            compiled_re = format
+    else:
+        compiled_re = TimeRE(locale_time).compile(format)
+    if data_string is False:
+        return compiled_re
+    else:
+        found = compiled_re.match(data_string)
+        if not found:
+            raise ValueError("time data did not match format")
+        year = month = day = hour = minute = second = weekday = julian = tz = -1
+        found_dict = found.groupdict()
+        for group_key in found_dict.iterkeys():
+            if group_key in 'yY':
+                if group_key is 'y':
+                    year = int("%s%s" % (time.strftime("%Y")[:-2], found_dict['y']))
+                else:
+                    year = int(found_dict['Y'])
+            elif group_key in 'Bbm':
+                if group_key is 'm':
+                    month = int(found_dict['m'])
+                elif group_key is 'B':
+                    month = locale_time.f_month.index(found_dict['B'])
+                else:
+                    month = locale_time.a_month.index(found_dict['b'])
+            elif group_key is 'd':
+                day = int(found_dict['d'])
+            elif group_key in 'HI':
+                if group_key is 'H':
+                    hour = int(found_dict['H'])
+                else:
+                    hour = int(found_dict['I'])
+                    if found_dict.has_key('p'):
+                        if found_dict['p'] == locale_time.am_pm[1]:
+                            hour += 12
+                        else:
+                            if hour is 12:
+                                hour = 0
+            elif group_key is 'M':
+                minute = int(found_dict['M'])
+            elif group_key is 'S':
+                second = int(found_dict['S'])
+            elif group_key in 'Aaw':
+                if group_key is 'A':
+                    weekday = locale_time.f_weekday.index(found_dict['A'])
+                elif group_key is 'a':
+                    weekday = locale_time.a_weekday.index(found_dict['a'])
+                else:
+                    weekday = int(found_dict['w'])
+                    if weekday == 0:
+                        weekday = 6
+                    else:
+                        weekday -= 1
+            elif group_key is 'j':
+                julian = int(found_dict['j'])
+            elif group_key is 'Z':
+                if locale_time.timezone[0] == found_dict['Z']:
+                    tz = 0
+                elif locale_time.timezone[1] == found_dict['Z']:
+                    tz = 1
+                elif locale_time.timezone[2] == found_dict['Z']:
+                    tz = 0
+        if julian == -1 and year != -1 and month != -1 and day != -1:
+            julian = julianday(year, month, day)
+        if (month == -1 or day == -1) and julian != -1 and year != -1:
+            year,month,day = gregorian(julian, year)
+        if weekday == -1 and year != -1 and month != -1 and day != -1:
+            weekday = dayofweek(year, month, day)
+        return time.struct_time((year,month,day,hour,minute,second,weekday,
+                                julian,tz))
+
+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 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 a 3-item list containing the 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