344 lines
11 KiB
Python
344 lines
11 KiB
Python
# -*- coding: utf-8 -*-
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from __future__ import absolute_import
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from __future__ import unicode_literals
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from datetime import datetime
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from dateutil import tz
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import re
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try:
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from functools import lru_cache
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except ImportError: # pragma: no cover
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from backports.functools_lru_cache import lru_cache # pragma: no cover
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from arrow import locales
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class ParserError(RuntimeError):
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pass
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class DateTimeParser(object):
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_FORMAT_RE = re.compile('(YYY?Y?|MM?M?M?|Do|DD?D?D?|d?d?d?d|HH?|hh?|mm?|ss?|S+|ZZ?Z?|a|A|X)')
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_ESCAPE_RE = re.compile('\[[^\[\]]*\]')
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_ONE_OR_MORE_DIGIT_RE = re.compile('\d+')
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_ONE_OR_TWO_DIGIT_RE = re.compile('\d{1,2}')
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_FOUR_DIGIT_RE = re.compile('\d{4}')
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_TWO_DIGIT_RE = re.compile('\d{2}')
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_TZ_RE = re.compile('[+\-]?\d{2}:?(\d{2})?')
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_TZ_NAME_RE = re.compile('\w[\w+\-/]+')
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_BASE_INPUT_RE_MAP = {
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'YYYY': _FOUR_DIGIT_RE,
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'YY': _TWO_DIGIT_RE,
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'MM': _TWO_DIGIT_RE,
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'M': _ONE_OR_TWO_DIGIT_RE,
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'DD': _TWO_DIGIT_RE,
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'D': _ONE_OR_TWO_DIGIT_RE,
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'HH': _TWO_DIGIT_RE,
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'H': _ONE_OR_TWO_DIGIT_RE,
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'hh': _TWO_DIGIT_RE,
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'h': _ONE_OR_TWO_DIGIT_RE,
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'mm': _TWO_DIGIT_RE,
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'm': _ONE_OR_TWO_DIGIT_RE,
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'ss': _TWO_DIGIT_RE,
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's': _ONE_OR_TWO_DIGIT_RE,
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'X': re.compile('\d+'),
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'ZZZ': _TZ_NAME_RE,
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'ZZ': _TZ_RE,
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'Z': _TZ_RE,
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'S': _ONE_OR_MORE_DIGIT_RE,
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}
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MARKERS = ['YYYY', 'MM', 'DD']
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SEPARATORS = ['-', '/', '.']
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def __init__(self, locale='en_us', cache_size=0):
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self.locale = locales.get_locale(locale)
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self._input_re_map = self._BASE_INPUT_RE_MAP.copy()
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self._input_re_map.update({
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'MMMM': self._choice_re(self.locale.month_names[1:], re.IGNORECASE),
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'MMM': self._choice_re(self.locale.month_abbreviations[1:],
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re.IGNORECASE),
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'Do': re.compile(self.locale.ordinal_day_re),
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'dddd': self._choice_re(self.locale.day_names[1:], re.IGNORECASE),
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'ddd': self._choice_re(self.locale.day_abbreviations[1:],
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re.IGNORECASE),
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'd': re.compile(r"[1-7]"),
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'a': self._choice_re(
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(self.locale.meridians['am'], self.locale.meridians['pm'])
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),
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# note: 'A' token accepts both 'am/pm' and 'AM/PM' formats to
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# ensure backwards compatibility of this token
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'A': self._choice_re(self.locale.meridians.values())
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})
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if cache_size > 0:
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self._generate_pattern_re =\
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lru_cache(maxsize=cache_size)(self._generate_pattern_re)
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def parse_iso(self, string):
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has_time = 'T' in string or ' ' in string.strip()
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space_divider = ' ' in string.strip()
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if has_time:
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if space_divider:
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date_string, time_string = string.split(' ', 1)
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else:
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date_string, time_string = string.split('T', 1)
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time_parts = re.split('[+-]', time_string, 1)
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has_tz = len(time_parts) > 1
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has_seconds = time_parts[0].count(':') > 1
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has_subseconds = re.search('[.,]', time_parts[0])
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if has_subseconds:
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formats = ['YYYY-MM-DDTHH:mm:ss%sS' % has_subseconds.group()]
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elif has_seconds:
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formats = ['YYYY-MM-DDTHH:mm:ss']
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else:
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formats = ['YYYY-MM-DDTHH:mm']
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else:
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has_tz = False
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# generate required formats: YYYY-MM-DD, YYYY-MM-DD, YYYY
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# using various separators: -, /, .
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l = len(self.MARKERS)
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formats = [separator.join(self.MARKERS[:l-i])
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for i in range(l)
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for separator in self.SEPARATORS]
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if has_time and has_tz:
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formats = [f + 'Z' for f in formats]
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if space_divider:
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formats = [item.replace('T', ' ', 1) for item in formats]
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return self._parse_multiformat(string, formats)
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def _generate_pattern_re(self, fmt):
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# fmt is a string of tokens like 'YYYY-MM-DD'
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# we construct a new string by replacing each
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# token by its pattern:
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# 'YYYY-MM-DD' -> '(?P<YYYY>\d{4})-(?P<MM>\d{2})-(?P<DD>\d{2})'
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tokens = []
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offset = 0
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# Extract the bracketed expressions to be reinserted later.
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escaped_fmt = re.sub(self._ESCAPE_RE, "#", fmt)
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# Any number of S is the same as one.
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escaped_fmt = re.sub('S+', 'S', escaped_fmt)
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escaped_data = re.findall(self._ESCAPE_RE, fmt)
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fmt_pattern = escaped_fmt
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for m in self._FORMAT_RE.finditer(escaped_fmt):
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token = m.group(0)
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try:
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input_re = self._input_re_map[token]
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except KeyError:
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raise ParserError('Unrecognized token \'{0}\''.format(token))
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input_pattern = '(?P<{0}>{1})'.format(token, input_re.pattern)
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tokens.append(token)
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# a pattern doesn't have the same length as the token
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# it replaces! We keep the difference in the offset variable.
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# This works because the string is scanned left-to-right and matches
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# are returned in the order found by finditer.
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fmt_pattern = fmt_pattern[:m.start() + offset] + input_pattern + fmt_pattern[m.end() + offset:]
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offset += len(input_pattern) - (m.end() - m.start())
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final_fmt_pattern = ""
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a = fmt_pattern.split("#")
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b = escaped_data
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# Due to the way Python splits, 'a' will always be longer
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for i in range(len(a)):
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final_fmt_pattern += a[i]
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if i < len(b):
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final_fmt_pattern += b[i][1:-1]
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return tokens, re.compile(final_fmt_pattern, flags=re.IGNORECASE)
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def parse(self, string, fmt):
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if isinstance(fmt, list):
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return self._parse_multiformat(string, fmt)
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fmt_tokens, fmt_pattern_re = self._generate_pattern_re(fmt)
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match = fmt_pattern_re.search(string)
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if match is None:
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raise ParserError('Failed to match \'{0}\' when parsing \'{1}\''
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.format(fmt_pattern_re.pattern, string))
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parts = {}
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for token in fmt_tokens:
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if token == 'Do':
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value = match.group('value')
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else:
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value = match.group(token)
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self._parse_token(token, value, parts)
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return self._build_datetime(parts)
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def _parse_token(self, token, value, parts):
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if token == 'YYYY':
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parts['year'] = int(value)
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elif token == 'YY':
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value = int(value)
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parts['year'] = 1900 + value if value > 68 else 2000 + value
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elif token in ['MMMM', 'MMM']:
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parts['month'] = self.locale.month_number(value.lower())
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elif token in ['MM', 'M']:
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parts['month'] = int(value)
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elif token in ['DD', 'D']:
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parts['day'] = int(value)
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elif token in ['Do']:
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parts['day'] = int(value)
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elif token.upper() in ['HH', 'H']:
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parts['hour'] = int(value)
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elif token in ['mm', 'm']:
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parts['minute'] = int(value)
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elif token in ['ss', 's']:
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parts['second'] = int(value)
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elif token == 'S':
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# We have the *most significant* digits of an arbitrary-precision integer.
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# We want the six most significant digits as an integer, rounded.
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# FIXME: add nanosecond support somehow?
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value = value.ljust(7, str('0'))
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# floating-point (IEEE-754) defaults to half-to-even rounding
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seventh_digit = int(value[6])
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if seventh_digit == 5:
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rounding = int(value[5]) % 2
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elif seventh_digit > 5:
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rounding = 1
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else:
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rounding = 0
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parts['microsecond'] = int(value[:6]) + rounding
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elif token == 'X':
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parts['timestamp'] = int(value)
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elif token in ['ZZZ', 'ZZ', 'Z']:
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parts['tzinfo'] = TzinfoParser.parse(value)
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elif token in ['a', 'A']:
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if value in (
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self.locale.meridians['am'],
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self.locale.meridians['AM']
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):
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parts['am_pm'] = 'am'
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elif value in (
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self.locale.meridians['pm'],
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self.locale.meridians['PM']
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):
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parts['am_pm'] = 'pm'
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@staticmethod
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def _build_datetime(parts):
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timestamp = parts.get('timestamp')
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if timestamp:
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tz_utc = tz.tzutc()
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return datetime.fromtimestamp(timestamp, tz=tz_utc)
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am_pm = parts.get('am_pm')
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hour = parts.get('hour', 0)
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if am_pm == 'pm' and hour < 12:
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hour += 12
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elif am_pm == 'am' and hour == 12:
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hour = 0
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return datetime(year=parts.get('year', 1), month=parts.get('month', 1),
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day=parts.get('day', 1), hour=hour, minute=parts.get('minute', 0),
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second=parts.get('second', 0), microsecond=parts.get('microsecond', 0),
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tzinfo=parts.get('tzinfo'))
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def _parse_multiformat(self, string, formats):
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_datetime = None
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for fmt in formats:
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try:
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_datetime = self.parse(string, fmt)
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break
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except ParserError:
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pass
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if _datetime is None:
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raise ParserError('Could not match input to any of {0} on \'{1}\''.format(formats, string))
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return _datetime
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@staticmethod
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def _map_lookup(input_map, key):
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try:
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return input_map[key]
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except KeyError:
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raise ParserError('Could not match "{0}" to {1}'.format(key, input_map))
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@staticmethod
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def _try_timestamp(string):
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try:
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return float(string)
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except:
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return None
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@staticmethod
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def _choice_re(choices, flags=0):
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return re.compile('({0})'.format('|'.join(choices)), flags=flags)
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class TzinfoParser(object):
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_TZINFO_RE = re.compile('([+\-])?(\d\d):?(\d\d)?')
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@classmethod
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def parse(cls, string):
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tzinfo = None
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if string == 'local':
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tzinfo = tz.tzlocal()
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elif string in ['utc', 'UTC']:
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tzinfo = tz.tzutc()
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else:
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iso_match = cls._TZINFO_RE.match(string)
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if iso_match:
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sign, hours, minutes = iso_match.groups()
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if minutes is None:
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minutes = 0
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seconds = int(hours) * 3600 + int(minutes) * 60
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if sign == '-':
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seconds *= -1
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tzinfo = tz.tzoffset(None, seconds)
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else:
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tzinfo = tz.gettz(string)
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if tzinfo is None:
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raise ParserError('Could not parse timezone expression "{0}"'.format(string))
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return tzinfo
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