61 lines
1.6 KiB
Python
61 lines
1.6 KiB
Python
# -*- coding: utf-8 -*-
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# This file is part of convertdate.
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# http://github.com/fitnr/convertdate
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# Licensed under the MIT license:
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# http://opensource.org/licenses/MIT
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# Copyright (c) 2016, fitnr <fitnr@fakeisthenewreal>
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from math import trunc
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from .utils import ceil, jwday, monthcalendarhelper
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from . import gregorian
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EPOCH = 1948439.5
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WEEKDAYS = ("al-'ahad", "al-'ithnayn",
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"ath-thalatha'", "al-'arb`a'",
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"al-khamis", "al-jum`a", "as-sabt")
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HAS_29_DAYS = (2, 4, 6, 8, 10)
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HAS_30_DAYS = (1, 3, 5, 7, 9, 11)
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def leap(year):
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'''Is a given year a leap year in the Islamic calendar'''
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return (((year * 11) + 14) % 30) < 11
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def to_jd(year, month, day):
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'''Determine Julian day count from Islamic date'''
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return (day + ceil(29.5 * (month - 1)) + (year - 1) * 354 + trunc((3 + (11 * year)) / 30) + EPOCH) - 1
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def from_jd(jd):
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'''Calculate Islamic date from Julian day'''
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jd = trunc(jd) + 0.5
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year = trunc(((30 * (jd - EPOCH)) + 10646) / 10631)
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month = min(12, ceil((jd - (29 + to_jd(year, 1, 1))) / 29.5) + 1)
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day = int(jd - to_jd(year, month, 1)) + 1
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return (year, month, day)
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def from_gregorian(year, month, day):
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return from_jd(gregorian.to_jd(year, month, day))
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def to_gregorian(year, month, day):
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return gregorian.from_jd(to_jd(year, month, day))
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def month_length(year, month):
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if month in HAS_30_DAYS or (month == 12 and leap(year)):
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return 30
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return 29
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def monthcalendar(year, month):
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start_weekday = jwday(to_jd(year, month, 1))
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monthlen = month_length(year, month)
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return monthcalendarhelper(start_weekday, monthlen)
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