Show strptime.py syntax highlighted
"""Strptime-related classes and functions.
CLASSES:
TimeRE -- Creates regexes for pattern matching a string of text containing
time information
FUNCTIONS:
strptime -- Calculates the time struct represented by the passed-in string
"""
import time
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']
class TimeRE(dict):
"""Handle conversion from format directives to regexes."""
def __init__(self):
"""Create keys/values.
Order of execution is important for dependency reasons.
"""
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(['monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday', 'sunday'], 'A'),
'a': self.__seqToRE(['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun'], 'a'),
'B': self.__seqToRE(['january', 'february', 'march', 'april', 'may', 'june', 'july', 'august', 'september', 'october', 'november', 'december'], 'B'),
'b': self.__seqToRE(['jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul', 'aug', 'sep', 'oct', 'nov', 'dec'], 'b'),
'p': self.__seqToRE(['am', 'pm'], 'p'),
'Z': self.__seqToRE(['utc', 'cst', 'gmt', 'cst'], 'Z'),
'%': '%'})
base.__setitem__('W', base.__getitem__('U').replace('U', 'W'))
base.__setitem__('c', self.pattern('%a %b %d %H:%M:%S %Y'))
base.__setitem__('x', self.pattern('%m/%d/%y'))
base.__setitem__('X', self.pattern('%H:%M:%S'))
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
_cache_lock.acquire()
try:
time_re = _TimeRE_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 = ['', 'january', 'february', 'march', 'april', 'may', 'june', 'july', 'august', 'september', 'october', 'november', 'december'].index(found_dict['B'].lower())
elif group_key == 'b':
month = ['', 'jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul', 'aug', 'sep', 'oct', 'nov', 'dec'].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 ('', 'am'):
# 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 == 'pm':
# 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 = ['monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday', 'sunday'].index(found_dict['A'].lower())
elif group_key == 'a':
weekday = ['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun'].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((frozenset(['utc', 'cst', 'gmt']), frozenset(['cst']))):
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))
See more files for this project here