1"""Strptime-related classes and functions. 2 3CLASSES: 4 LocaleTime -- Discovers and stores locale-specific time information 5 TimeRE -- Creates regexes for pattern matching a string of text containing 6 time information 7 8FUNCTIONS: 9 _getlang -- Figure out what language is being used for the locale 10 strptime -- Calculates the time struct represented by the passed-in string 11 12""" 13import time 14import locale 15import calendar 16from re import compile as re_compile 17from re import IGNORECASE 18from re import escape as re_escape 19from datetime import (date as datetime_date, 20 timedelta as datetime_timedelta, 21 timezone as datetime_timezone) 22from _thread import allocate_lock as _thread_allocate_lock 23 24__all__ = [] 25 26def _getlang(): 27 # Figure out what the current language is set to. 28 return locale.getlocale(locale.LC_TIME) 29 30class LocaleTime(object): 31 """Stores and handles locale-specific information related to time. 32 33 ATTRIBUTES: 34 f_weekday -- full weekday names (7-item list) 35 a_weekday -- abbreviated weekday names (7-item list) 36 f_month -- full month names (13-item list; dummy value in [0], which 37 is added by code) 38 a_month -- abbreviated month names (13-item list, dummy value in 39 [0], which is added by code) 40 am_pm -- AM/PM representation (2-item list) 41 LC_date_time -- format string for date/time representation (string) 42 LC_date -- format string for date representation (string) 43 LC_time -- format string for time representation (string) 44 timezone -- daylight- and non-daylight-savings timezone representation 45 (2-item list of sets) 46 lang -- Language used by instance (2-item tuple) 47 """ 48 49 def __init__(self): 50 """Set all attributes. 51 52 Order of methods called matters for dependency reasons. 53 54 The locale language is set at the offset and then checked again before 55 exiting. This is to make sure that the attributes were not set with a 56 mix of information from more than one locale. This would most likely 57 happen when using threads where one thread calls a locale-dependent 58 function while another thread changes the locale while the function in 59 the other thread is still running. Proper coding would call for 60 locks to prevent changing the locale while locale-dependent code is 61 running. The check here is done in case someone does not think about 62 doing this. 63 64 Only other possible issue is if someone changed the timezone and did 65 not call tz.tzset . That is an issue for the programmer, though, 66 since changing the timezone is worthless without that call. 67 68 """ 69 self.lang = _getlang() 70 self.__calc_weekday() 71 self.__calc_month() 72 self.__calc_am_pm() 73 self.__calc_timezone() 74 self.__calc_date_time() 75 if _getlang() != self.lang: 76 raise ValueError("locale changed during initialization") 77 if time.tzname != self.tzname or time.daylight != self.daylight: 78 raise ValueError("timezone changed during initialization") 79 80 def __pad(self, seq, front): 81 # Add '' to seq to either the front (is True), else the back. 82 seq = list(seq) 83 if front: 84 seq.insert(0, '') 85 else: 86 seq.append('') 87 return seq 88 89 def __calc_weekday(self): 90 # Set self.a_weekday and self.f_weekday using the calendar 91 # module. 92 a_weekday = [calendar.day_abbr[i].lower() for i in range(7)] 93 f_weekday = [calendar.day_name[i].lower() for i in range(7)] 94 self.a_weekday = a_weekday 95 self.f_weekday = f_weekday 96 97 def __calc_month(self): 98 # Set self.f_month and self.a_month using the calendar module. 99 a_month = [calendar.month_abbr[i].lower() for i in range(13)] 100 f_month = [calendar.month_name[i].lower() for i in range(13)] 101 self.a_month = a_month 102 self.f_month = f_month 103 104 def __calc_am_pm(self): 105 # Set self.am_pm by using time.strftime(). 106 107 # The magic date (1999,3,17,hour,44,55,2,76,0) is not really that 108 # magical; just happened to have used it everywhere else where a 109 # static date was needed. 110 am_pm = [] 111 for hour in (1, 22): 112 time_tuple = time.struct_time((1999,3,17,hour,44,55,2,76,0)) 113 am_pm.append(time.strftime("%p", time_tuple).lower()) 114 self.am_pm = am_pm 115 116 def __calc_date_time(self): 117 # Set self.date_time, self.date, & self.time by using 118 # time.strftime(). 119 120 # Use (1999,3,17,22,44,55,2,76,0) for magic date because the amount of 121 # overloaded numbers is minimized. The order in which searches for 122 # values within the format string is very important; it eliminates 123 # possible ambiguity for what something represents. 124 time_tuple = time.struct_time((1999,3,17,22,44,55,2,76,0)) 125 date_time = [None, None, None] 126 date_time[0] = time.strftime("%c", time_tuple).lower() 127 date_time[1] = time.strftime("%x", time_tuple).lower() 128 date_time[2] = time.strftime("%X", time_tuple).lower() 129 replacement_pairs = [('%', '%%'), (self.f_weekday[2], '%A'), 130 (self.f_month[3], '%B'), (self.a_weekday[2], '%a'), 131 (self.a_month[3], '%b'), (self.am_pm[1], '%p'), 132 ('1999', '%Y'), ('99', '%y'), ('22', '%H'), 133 ('44', '%M'), ('55', '%S'), ('76', '%j'), 134 ('17', '%d'), ('03', '%m'), ('3', '%m'), 135 # '3' needed for when no leading zero. 136 ('2', '%w'), ('10', '%I')] 137 replacement_pairs.extend([(tz, "%Z") for tz_values in self.timezone 138 for tz in tz_values]) 139 for offset,directive in ((0,'%c'), (1,'%x'), (2,'%X')): 140 current_format = date_time[offset] 141 for old, new in replacement_pairs: 142 # Must deal with possible lack of locale info 143 # manifesting itself as the empty string (e.g., Swedish's 144 # lack of AM/PM info) or a platform returning a tuple of empty 145 # strings (e.g., MacOS 9 having timezone as ('','')). 146 if old: 147 current_format = current_format.replace(old, new) 148 # If %W is used, then Sunday, 2005-01-03 will fall on week 0 since 149 # 2005-01-03 occurs before the first Monday of the year. Otherwise 150 # %U is used. 151 time_tuple = time.struct_time((1999,1,3,1,1,1,6,3,0)) 152 if '00' in time.strftime(directive, time_tuple): 153 U_W = '%W' 154 else: 155 U_W = '%U' 156 date_time[offset] = current_format.replace('11', U_W) 157 self.LC_date_time = date_time[0] 158 self.LC_date = date_time[1] 159 self.LC_time = date_time[2] 160 161 def __calc_timezone(self): 162 # Set self.timezone by using time.tzname. 163 # Do not worry about possibility of time.tzname[0] == time.tzname[1] 164 # and time.daylight; handle that in strptime. 165 try: 166 time.tzset() 167 except AttributeError: 168 pass 169 self.tzname = time.tzname 170 self.daylight = time.daylight 171 no_saving = frozenset({"utc", "gmt", self.tzname[0].lower()}) 172 if self.daylight: 173 has_saving = frozenset({self.tzname[1].lower()}) 174 else: 175 has_saving = frozenset() 176 self.timezone = (no_saving, has_saving) 177 178 179class TimeRE(dict): 180 """Handle conversion from format directives to regexes.""" 181 182 def __init__(self, locale_time=None): 183 """Create keys/values. 184 185 Order of execution is important for dependency reasons. 186 187 """ 188 if locale_time: 189 self.locale_time = locale_time 190 else: 191 self.locale_time = LocaleTime() 192 base = super() 193 base.__init__({ 194 # The " \d" part of the regex is to make %c from ANSI C work 195 'd': r"(?P<d>3[0-1]|[1-2]\d|0[1-9]|[1-9]| [1-9])", 196 'f': r"(?P<f>[0-9]{1,6})", 197 'H': r"(?P<H>2[0-3]|[0-1]\d|\d)", 198 'I': r"(?P<I>1[0-2]|0[1-9]|[1-9])", 199 'G': r"(?P<G>\d\d\d\d)", 200 '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])", 201 'm': r"(?P<m>1[0-2]|0[1-9]|[1-9])", 202 'M': r"(?P<M>[0-5]\d|\d)", 203 'S': r"(?P<S>6[0-1]|[0-5]\d|\d)", 204 'U': r"(?P<U>5[0-3]|[0-4]\d|\d)", 205 'w': r"(?P<w>[0-6])", 206 'u': r"(?P<u>[1-7])", 207 'V': r"(?P<V>5[0-3]|0[1-9]|[1-4]\d|\d)", 208 # W is set below by using 'U' 209 'y': r"(?P<y>\d\d)", 210 #XXX: Does 'Y' need to worry about having less or more than 211 # 4 digits? 212 'Y': r"(?P<Y>\d\d\d\d)", 213 'z': r"(?P<z>[+-]\d\d:?[0-5]\d(:?[0-5]\d(\.\d{1,6})?)?|Z)", 214 'A': self.__seqToRE(self.locale_time.f_weekday, 'A'), 215 'a': self.__seqToRE(self.locale_time.a_weekday, 'a'), 216 'B': self.__seqToRE(self.locale_time.f_month[1:], 'B'), 217 'b': self.__seqToRE(self.locale_time.a_month[1:], 'b'), 218 'p': self.__seqToRE(self.locale_time.am_pm, 'p'), 219 'Z': self.__seqToRE((tz for tz_names in self.locale_time.timezone 220 for tz in tz_names), 221 'Z'), 222 '%': '%'}) 223 base.__setitem__('W', base.__getitem__('U').replace('U', 'W')) 224 base.__setitem__('c', self.pattern(self.locale_time.LC_date_time)) 225 base.__setitem__('x', self.pattern(self.locale_time.LC_date)) 226 base.__setitem__('X', self.pattern(self.locale_time.LC_time)) 227 228 def __seqToRE(self, to_convert, directive): 229 """Convert a list to a regex string for matching a directive. 230 231 Want possible matching values to be from longest to shortest. This 232 prevents the possibility of a match occurring for a value that also 233 a substring of a larger value that should have matched (e.g., 'abc' 234 matching when 'abcdef' should have been the match). 235 236 """ 237 to_convert = sorted(to_convert, key=len, reverse=True) 238 for value in to_convert: 239 if value != '': 240 break 241 else: 242 return '' 243 regex = '|'.join(re_escape(stuff) for stuff in to_convert) 244 regex = '(?P<%s>%s' % (directive, regex) 245 return '%s)' % regex 246 247 def pattern(self, format): 248 """Return regex pattern for the format string. 249 250 Need to make sure that any characters that might be interpreted as 251 regex syntax are escaped. 252 253 """ 254 processed_format = '' 255 # The sub() call escapes all characters that might be misconstrued 256 # as regex syntax. Cannot use re.escape since we have to deal with 257 # format directives (%m, etc.). 258 regex_chars = re_compile(r"([\\.^$*+?\(\){}\[\]|])") 259 format = regex_chars.sub(r"\\\1", format) 260 whitespace_replacement = re_compile(r'\s+') 261 format = whitespace_replacement.sub(r'\\s+', format) 262 while '%' in format: 263 directive_index = format.index('%')+1 264 processed_format = "%s%s%s" % (processed_format, 265 format[:directive_index-1], 266 self[format[directive_index]]) 267 format = format[directive_index+1:] 268 return "%s%s" % (processed_format, format) 269 270 def compile(self, format): 271 """Return a compiled re object for the format string.""" 272 return re_compile(self.pattern(format), IGNORECASE) 273 274_cache_lock = _thread_allocate_lock() 275# DO NOT modify _TimeRE_cache or _regex_cache without acquiring the cache lock 276# first! 277_TimeRE_cache = TimeRE() 278_CACHE_MAX_SIZE = 5 # Max number of regexes stored in _regex_cache 279_regex_cache = {} 280 281def _calc_julian_from_U_or_W(year, week_of_year, day_of_week, week_starts_Mon): 282 """Calculate the Julian day based on the year, week of the year, and day of 283 the week, with week_start_day representing whether the week of the year 284 assumes the week starts on Sunday or Monday (6 or 0).""" 285 first_weekday = datetime_date(year, 1, 1).weekday() 286 # If we are dealing with the %U directive (week starts on Sunday), it's 287 # easier to just shift the view to Sunday being the first day of the 288 # week. 289 if not week_starts_Mon: 290 first_weekday = (first_weekday + 1) % 7 291 day_of_week = (day_of_week + 1) % 7 292 # Need to watch out for a week 0 (when the first day of the year is not 293 # the same as that specified by %U or %W). 294 week_0_length = (7 - first_weekday) % 7 295 if week_of_year == 0: 296 return 1 + day_of_week - first_weekday 297 else: 298 days_to_week = week_0_length + (7 * (week_of_year - 1)) 299 return 1 + days_to_week + day_of_week 300 301 302def _calc_julian_from_V(iso_year, iso_week, iso_weekday): 303 """Calculate the Julian day based on the ISO 8601 year, week, and weekday. 304 ISO weeks start on Mondays, with week 01 being the week containing 4 Jan. 305 ISO week days range from 1 (Monday) to 7 (Sunday). 306 """ 307 correction = datetime_date(iso_year, 1, 4).isoweekday() + 3 308 ordinal = (iso_week * 7) + iso_weekday - correction 309 # ordinal may be negative or 0 now, which means the date is in the previous 310 # calendar year 311 if ordinal < 1: 312 ordinal += datetime_date(iso_year, 1, 1).toordinal() 313 iso_year -= 1 314 ordinal -= datetime_date(iso_year, 1, 1).toordinal() 315 return iso_year, ordinal 316 317 318def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"): 319 """Return a 2-tuple consisting of a time struct and an int containing 320 the number of microseconds based on the input string and the 321 format string.""" 322 323 for index, arg in enumerate([data_string, format]): 324 if not isinstance(arg, str): 325 msg = "strptime() argument {} must be str, not {}" 326 raise TypeError(msg.format(index, type(arg))) 327 328 global _TimeRE_cache, _regex_cache 329 with _cache_lock: 330 locale_time = _TimeRE_cache.locale_time 331 if (_getlang() != locale_time.lang or 332 time.tzname != locale_time.tzname or 333 time.daylight != locale_time.daylight): 334 _TimeRE_cache = TimeRE() 335 _regex_cache.clear() 336 locale_time = _TimeRE_cache.locale_time 337 if len(_regex_cache) > _CACHE_MAX_SIZE: 338 _regex_cache.clear() 339 format_regex = _regex_cache.get(format) 340 if not format_regex: 341 try: 342 format_regex = _TimeRE_cache.compile(format) 343 # KeyError raised when a bad format is found; can be specified as 344 # \\, in which case it was a stray % but with a space after it 345 except KeyError as err: 346 bad_directive = err.args[0] 347 if bad_directive == "\\": 348 bad_directive = "%" 349 del err 350 raise ValueError("'%s' is a bad directive in format '%s'" % 351 (bad_directive, format)) from None 352 # IndexError only occurs when the format string is "%" 353 except IndexError: 354 raise ValueError("stray %% in format '%s'" % format) from None 355 _regex_cache[format] = format_regex 356 found = format_regex.match(data_string) 357 if not found: 358 raise ValueError("time data %r does not match format %r" % 359 (data_string, format)) 360 if len(data_string) != found.end(): 361 raise ValueError("unconverted data remains: %s" % 362 data_string[found.end():]) 363 364 iso_year = year = None 365 month = day = 1 366 hour = minute = second = fraction = 0 367 tz = -1 368 gmtoff = None 369 gmtoff_fraction = 0 370 # Default to -1 to signify that values not known; not critical to have, 371 # though 372 iso_week = week_of_year = None 373 week_of_year_start = None 374 # weekday and julian defaulted to None so as to signal need to calculate 375 # values 376 weekday = julian = None 377 found_dict = found.groupdict() 378 for group_key in found_dict.keys(): 379 # Directives not explicitly handled below: 380 # c, x, X 381 # handled by making out of other directives 382 # U, W 383 # worthless without day of the week 384 if group_key == 'y': 385 year = int(found_dict['y']) 386 # Open Group specification for strptime() states that a %y 387 #value in the range of [00, 68] is in the century 2000, while 388 #[69,99] is in the century 1900 389 if year <= 68: 390 year += 2000 391 else: 392 year += 1900 393 elif group_key == 'Y': 394 year = int(found_dict['Y']) 395 elif group_key == 'G': 396 iso_year = int(found_dict['G']) 397 elif group_key == 'm': 398 month = int(found_dict['m']) 399 elif group_key == 'B': 400 month = locale_time.f_month.index(found_dict['B'].lower()) 401 elif group_key == 'b': 402 month = locale_time.a_month.index(found_dict['b'].lower()) 403 elif group_key == 'd': 404 day = int(found_dict['d']) 405 elif group_key == 'H': 406 hour = int(found_dict['H']) 407 elif group_key == 'I': 408 hour = int(found_dict['I']) 409 ampm = found_dict.get('p', '').lower() 410 # If there was no AM/PM indicator, we'll treat this like AM 411 if ampm in ('', locale_time.am_pm[0]): 412 # We're in AM so the hour is correct unless we're 413 # looking at 12 midnight. 414 # 12 midnight == 12 AM == hour 0 415 if hour == 12: 416 hour = 0 417 elif ampm == locale_time.am_pm[1]: 418 # We're in PM so we need to add 12 to the hour unless 419 # we're looking at 12 noon. 420 # 12 noon == 12 PM == hour 12 421 if hour != 12: 422 hour += 12 423 elif group_key == 'M': 424 minute = int(found_dict['M']) 425 elif group_key == 'S': 426 second = int(found_dict['S']) 427 elif group_key == 'f': 428 s = found_dict['f'] 429 # Pad to always return microseconds. 430 s += "0" * (6 - len(s)) 431 fraction = int(s) 432 elif group_key == 'A': 433 weekday = locale_time.f_weekday.index(found_dict['A'].lower()) 434 elif group_key == 'a': 435 weekday = locale_time.a_weekday.index(found_dict['a'].lower()) 436 elif group_key == 'w': 437 weekday = int(found_dict['w']) 438 if weekday == 0: 439 weekday = 6 440 else: 441 weekday -= 1 442 elif group_key == 'u': 443 weekday = int(found_dict['u']) 444 weekday -= 1 445 elif group_key == 'j': 446 julian = int(found_dict['j']) 447 elif group_key in ('U', 'W'): 448 week_of_year = int(found_dict[group_key]) 449 if group_key == 'U': 450 # U starts week on Sunday. 451 week_of_year_start = 6 452 else: 453 # W starts week on Monday. 454 week_of_year_start = 0 455 elif group_key == 'V': 456 iso_week = int(found_dict['V']) 457 elif group_key == 'z': 458 z = found_dict['z'] 459 if z == 'Z': 460 gmtoff = 0 461 else: 462 if z[3] == ':': 463 z = z[:3] + z[4:] 464 if len(z) > 5: 465 if z[5] != ':': 466 msg = f"Inconsistent use of : in {found_dict['z']}" 467 raise ValueError(msg) 468 z = z[:5] + z[6:] 469 hours = int(z[1:3]) 470 minutes = int(z[3:5]) 471 seconds = int(z[5:7] or 0) 472 gmtoff = (hours * 60 * 60) + (minutes * 60) + seconds 473 gmtoff_remainder = z[8:] 474 # Pad to always return microseconds. 475 gmtoff_remainder_padding = "0" * (6 - len(gmtoff_remainder)) 476 gmtoff_fraction = int(gmtoff_remainder + gmtoff_remainder_padding) 477 if z.startswith("-"): 478 gmtoff = -gmtoff 479 gmtoff_fraction = -gmtoff_fraction 480 elif group_key == 'Z': 481 # Since -1 is default value only need to worry about setting tz if 482 # it can be something other than -1. 483 found_zone = found_dict['Z'].lower() 484 for value, tz_values in enumerate(locale_time.timezone): 485 if found_zone in tz_values: 486 # Deal with bad locale setup where timezone names are the 487 # same and yet time.daylight is true; too ambiguous to 488 # be able to tell what timezone has daylight savings 489 if (time.tzname[0] == time.tzname[1] and 490 time.daylight and found_zone not in ("utc", "gmt")): 491 break 492 else: 493 tz = value 494 break 495 # Deal with the cases where ambiguities arize 496 # don't assume default values for ISO week/year 497 if year is None and iso_year is not None: 498 if iso_week is None or weekday is None: 499 raise ValueError("ISO year directive '%G' must be used with " 500 "the ISO week directive '%V' and a weekday " 501 "directive ('%A', '%a', '%w', or '%u').") 502 if julian is not None: 503 raise ValueError("Day of the year directive '%j' is not " 504 "compatible with ISO year directive '%G'. " 505 "Use '%Y' instead.") 506 elif week_of_year is None and iso_week is not None: 507 if weekday is None: 508 raise ValueError("ISO week directive '%V' must be used with " 509 "the ISO year directive '%G' and a weekday " 510 "directive ('%A', '%a', '%w', or '%u').") 511 else: 512 raise ValueError("ISO week directive '%V' is incompatible with " 513 "the year directive '%Y'. Use the ISO year '%G' " 514 "instead.") 515 516 leap_year_fix = False 517 if year is None and month == 2 and day == 29: 518 year = 1904 # 1904 is first leap year of 20th century 519 leap_year_fix = True 520 elif year is None: 521 year = 1900 522 523 524 # If we know the week of the year and what day of that week, we can figure 525 # out the Julian day of the year. 526 if julian is None and weekday is not None: 527 if week_of_year is not None: 528 week_starts_Mon = True if week_of_year_start == 0 else False 529 julian = _calc_julian_from_U_or_W(year, week_of_year, weekday, 530 week_starts_Mon) 531 elif iso_year is not None and iso_week is not None: 532 year, julian = _calc_julian_from_V(iso_year, iso_week, weekday + 1) 533 if julian is not None and julian <= 0: 534 year -= 1 535 yday = 366 if calendar.isleap(year) else 365 536 julian += yday 537 538 if julian is None: 539 # Cannot pre-calculate datetime_date() since can change in Julian 540 # calculation and thus could have different value for the day of 541 # the week calculation. 542 # Need to add 1 to result since first day of the year is 1, not 0. 543 julian = datetime_date(year, month, day).toordinal() - \ 544 datetime_date(year, 1, 1).toordinal() + 1 545 else: # Assume that if they bothered to include Julian day (or if it was 546 # calculated above with year/week/weekday) it will be accurate. 547 datetime_result = datetime_date.fromordinal( 548 (julian - 1) + 549 datetime_date(year, 1, 1).toordinal()) 550 year = datetime_result.year 551 month = datetime_result.month 552 day = datetime_result.day 553 if weekday is None: 554 weekday = datetime_date(year, month, day).weekday() 555 # Add timezone info 556 tzname = found_dict.get("Z") 557 558 if leap_year_fix: 559 # the caller didn't supply a year but asked for Feb 29th. We couldn't 560 # use the default of 1900 for computations. We set it back to ensure 561 # that February 29th is smaller than March 1st. 562 year = 1900 563 564 return (year, month, day, 565 hour, minute, second, 566 weekday, julian, tz, tzname, gmtoff), fraction, gmtoff_fraction 567 568def _strptime_time(data_string, format="%a %b %d %H:%M:%S %Y"): 569 """Return a time struct based on the input string and the 570 format string.""" 571 tt = _strptime(data_string, format)[0] 572 return time.struct_time(tt[:time._STRUCT_TM_ITEMS]) 573 574def _strptime_datetime(cls, data_string, format="%a %b %d %H:%M:%S %Y"): 575 """Return a class cls instance based on the input string and the 576 format string.""" 577 tt, fraction, gmtoff_fraction = _strptime(data_string, format) 578 tzname, gmtoff = tt[-2:] 579 args = tt[:6] + (fraction,) 580 if gmtoff is not None: 581 tzdelta = datetime_timedelta(seconds=gmtoff, microseconds=gmtoff_fraction) 582 if tzname: 583 tz = datetime_timezone(tzdelta, tzname) 584 else: 585 tz = datetime_timezone(tzdelta) 586 args += (tz,) 587 588 return cls(*args) 589