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/*
* Copyright 2020 Adobe. All rights reserved.
* This file is licensed to you under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License. You may obtain a copy
* of the License at http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under
* the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
* OF ANY KIND, either express or implied. See the License for the specific language
* governing permissions and limitations under the License.
*/
// Portions of the code in this file are based on code from ICU.
// Original licensing can be found in the NOTICE file in the root directory of this source tree.
import {AnyCalendarDate, Calendar, CalendarIdentifier} from '../types';
import {CalendarDate} from '../CalendarDate';
import {mod} from '../utils';
const PERSIAN_EPOCH = 1948320;
// Number of days from the start of the year to the start of each month.
const MONTH_START = [
0, // Farvardin
31, // Ordibehesht
62, // Khordad
93, // Tir
124, // Mordad
155, // Shahrivar
186, // Mehr
216, // Aban
246, // Azar
276, // Dey
306, // Bahman
336 // Esfand
];
/**
* The Persian calendar is the main calendar used in Iran and Afghanistan. It has 12 months
* in each year, the first 6 of which have 31 days, and the next 5 have 30 days. The 12th month
* has either 29 or 30 days depending on whether it is a leap year. The Persian year starts
* around the March equinox.
*/
export class PersianCalendar implements Calendar {
identifier: CalendarIdentifier = 'persian';
fromJulianDay(jd: number): CalendarDate {
let daysSinceEpoch = jd - PERSIAN_EPOCH;
let year = 1 + Math.floor((33 * daysSinceEpoch + 3) / 12053);
let farvardin1 = 365 * (year - 1) + Math.floor((8 * year + 21) / 33);
let dayOfYear = daysSinceEpoch - farvardin1;
let month = dayOfYear < 216
? Math.floor(dayOfYear / 31)
: Math.floor((dayOfYear - 6) / 30);
let day = dayOfYear - MONTH_START[month] + 1;
return new CalendarDate(this, year, month + 1, day);
}
toJulianDay(date: AnyCalendarDate): number {
let jd = PERSIAN_EPOCH - 1 + 365 * (date.year - 1) + Math.floor((8 * date.year + 21) / 33);
jd += MONTH_START[date.month - 1];
jd += date.day;
return jd;
}
getMonthsInYear(): number {
return 12;
}
getDaysInMonth(date: AnyCalendarDate): number {
if (date.month <= 6) {
return 31;
}
if (date.month <= 11) {
return 30;
}
let isLeapYear = mod(25 * date.year + 11, 33) < 8;
return isLeapYear ? 30 : 29;
}
getEras(): string[] {
return ['AP'];
}
getYearsInEra(): number {
// 9378-10-10 persian is 9999-12-31 gregorian.
// Round down to 9377 to set the maximum full year.
return 9377;
}
}
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