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