text: """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)
              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 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:
              format_regex = time_re.compile(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
      # Calculations below assume 0 is a Monday
      if julian == -1 and week_of_year != -1 and weekday != -1:
          # Calculate how many days in week 0
          first_weekday = datetime_date(year, 1, 1).weekday()
          preceeding_days = 7 - first_weekday
          if preceeding_days == 7:
              preceeding_days = 0
          # Adjust for U directive so that calculations are not dependent on
          # directive used to figure out week of year
          if weekday == 6 and week_of_year_start == 6:
              week_of_year -= 1
          # If a year starts and ends on a Monday but a week is specified to
          # start on a Sunday we need to up the week to counter-balance the fact
          # that with %W that first Monday starts week 1 while with %U that is
          # week 0 and thus shifts everything by a week
          if weekday == 0 and first_weekday == 0 and week_of_year_start == 6:
              week_of_year += 1
          # If in week 0, then just figure out how many days from Jan 1 to day of
          # week specified, else calculate by multiplying week of year by 7,
          # adding in days in week 0, and the number of days from Monday to the
          # day of the week
          if week_of_year == 0:
              julian = 1 + weekday - first_weekday
          else:
              days_to_week = preceeding_days + (7 * (week_of_year - 1))
              julian = 1 + days_to_week + weekday
      # 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))
  