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# -*- coding: utf-8 -*-
# Copyright (c) 2014, Brandon Nielsen
# All rights reserved.
#
# This software may be modified and distributed under the terms
# of the BSD license. See the LICENSE file for details.
from datetime import datetime
from aniso8601.duration import parse_duration
from aniso8601.time import parse_datetime
from aniso8601.date import parse_date
def parse_interval(isointervalstr, intervaldelimiter='/', datetimedelimiter='T', relative=False):
#Given a string representing an ISO8601 interval, return a
#tuple of datetime.date or date.datetime objects representing the beginning
#and end of the specified interval. Valid formats are:
#
#<start>/<end>
#<start>/<duration>
#<duration>/<end>
#
#The <start> and <end> values can represent dates, or datetimes,
#not times.
#
#The format:
#
#<duration>
#
#Is expressly not supported as there is no way to provide the addtional
#required context.
firstpart, secondpart = isointervalstr.split(intervaldelimiter)
if firstpart[0] == 'P':
#<duration>/<end>
#Notice that these are not returned 'in order' (earlier to later), this
#is to maintain consistency with parsing <start>/<end> durations, as
#well as making repeating interval code cleaner. Users who desire
#durations to be in order can use the 'sorted' operator.
#We need to figure out if <end> is a date, or a datetime
if secondpart.find(datetimedelimiter) != -1:
#<end> is a datetime
duration = parse_duration(firstpart, relative=relative)
enddatetime = parse_datetime(secondpart, delimiter=datetimedelimiter)
return (enddatetime, enddatetime - duration)
else:
#<end> must just be a date
duration = parse_duration(firstpart, relative=relative)
enddate = parse_date(secondpart)
#See if we need to upconvert to datetime to preserve resolution
if firstpart.find(datetimedelimiter) != -1:
return (enddate, datetime.combine(enddate, datetime.min.time()) - duration)
else:
return (enddate, enddate - duration)
elif secondpart[0] == 'P':
#<start>/<duration>
#We need to figure out if <start> is a date, or a datetime
if firstpart.find(datetimedelimiter) != -1:
#<end> is a datetime
duration = parse_duration(secondpart, relative=relative)
startdatetime = parse_datetime(firstpart, delimiter=datetimedelimiter)
return (startdatetime, startdatetime + duration)
else:
#<start> must just be a date
duration = parse_duration(secondpart, relative=relative)
startdate = parse_date(firstpart)
#See if we need to upconvert to datetime to preserve resolution
if secondpart.find(datetimedelimiter) != -1:
return (startdate, datetime.combine(startdate, datetime.min.time()) + duration)
else:
return (startdate, startdate + duration)
else:
#<start>/<end>
if firstpart.find(datetimedelimiter) != -1 and secondpart.find(datetimedelimiter) != -1:
#Both parts are datetimes
return (parse_datetime(firstpart, delimiter=datetimedelimiter), parse_datetime(secondpart, delimiter=datetimedelimiter))
elif firstpart.find(datetimedelimiter) != -1 and secondpart.find(datetimedelimiter) == -1:
#First part is a datetime, second part is a date
return (parse_datetime(firstpart, delimiter=datetimedelimiter), parse_date(secondpart))
elif firstpart.find(datetimedelimiter) == -1 and secondpart.find(datetimedelimiter) != -1:
#First part is a date, second part is a datetime
return (parse_date(firstpart), parse_datetime(secondpart, delimiter=datetimedelimiter))
else:
#Both parts are dates
return (parse_date(firstpart), parse_date(secondpart))
def parse_repeating_interval(isointervalstr, intervaldelimiter='/', datetimedelimiter='T', relative=False):
#Given a string representing an ISO8601 interval repating, return a
#generator of datetime.date or date.datetime objects representing the
#dates specified by the repeating interval. Valid formats are:
#
#Rnn/<interval>
#R/<interval>
if isointervalstr[0] != 'R':
raise ValueError('String is not a valid ISO8601 repeating interval.')
#Parse the number of iterations
iterationpart, intervalpart = isointervalstr.split(intervaldelimiter, 1)
if len(iterationpart) > 1:
iterations = int(iterationpart[1:])
else:
iterations = None
interval = parse_interval(intervalpart, intervaldelimiter, datetimedelimiter, relative=relative)
intervaltimedelta = interval[1] - interval[0]
#Now, build and return the generator
if iterations != None:
return _date_generator(interval[0], intervaltimedelta, iterations)
else:
return _date_generator_unbounded(interval[0], intervaltimedelta)
def _date_generator(startdate, timedelta, iterations):
currentdate = startdate
currentiteration = 0
while currentiteration < iterations:
yield currentdate
#Update the values
currentdate += timedelta
currentiteration += 1
def _date_generator_unbounded(startdate, timedelta):
currentdate = startdate
while True:
yield currentdate
#Update the value
currentdate += timedelta
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