103 lines
2.4 KiB
Python
103 lines
2.4 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 = 1948320.5
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WEEKDAYS = ("Doshanbeh", "Seshhanbeh",
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"Chaharshanbeh", "Panjshanbeh",
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"Jomeh", "Shanbeh", "Yekshanbeh")
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HAS_31_DAYS = (1, 2, 3, 4, 5, 6)
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HAS_30_DAYS = (7, 8, 9, 10, 11)
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def leap(year):
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'''Is a given year a leap year in the Persian calendar ?'''
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if year > 0:
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y = 474
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else:
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y = 473
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return ((((((year - y % 2820) + 474) + 38) * 682) % 2816) < 682)
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def to_jd(year, month, day):
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'''Determine Julian day from Persian date'''
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if year >= 0:
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y = 474
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else:
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y = 473
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epbase = year - y
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epyear = 474 + (epbase % 2820)
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if month <= 7:
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m = (month - 1) * 31
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else:
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m = (month - 1) * 30 + 6
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return day + m + trunc(((epyear * 682) - 110) / 2816) + (epyear - 1) * 365 + trunc(epbase / 2820) * 1029983 + (EPOCH - 1)
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def from_jd(jd):
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'''Calculate Persian date from Julian day'''
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jd = trunc(jd) + 0.5
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depoch = jd - to_jd(475, 1, 1)
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cycle = trunc(depoch / 1029983)
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cyear = (depoch % 1029983)
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if cyear == 1029982:
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ycycle = 2820
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else:
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aux1 = trunc(cyear / 366)
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aux2 = cyear % 366
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ycycle = trunc(((2134 * aux1) + (2816 * aux2) + 2815) / 1028522) + aux1 + 1
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year = ycycle + (2820 * cycle) + 474
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if (year <= 0):
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year -= 1
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yday = (jd - to_jd(year, 1, 1)) + 1
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if yday <= 186:
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month = ceil(yday / 31)
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else:
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month = ceil((yday - 6) / 30)
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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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elif month in HAS_31_DAYS:
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return 31
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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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