/*
* PersianAlgoCal.js - Represent a Persian algorithmic calendar object.
*
* Copyright © 2014-2015,2018, JEDLSoft
*
* Licensed 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 CONDITIONS OF ANY KIND, either express or implied.
*
* See the License for the specific language governing permissions and
* limitations under the License.
*/
var MathUtils = require("./MathUtils.js");
var Calendar = require("./Calendar.js");
/**
* @class
* Construct a new Persian algorithmic calendar object. This class encodes information about
* a Persian algorithmic calendar.<p>
*
* @param {Object=} options Options governing the construction of this instance
* @constructor
* @extends Calendar
*/
var PersianAlgoCal = function(options) {
this.type = "persian-algo";
if (options && typeof(options.onLoad) === "function") {
options.onLoad(this);
}
};
/**
* the lengths of each month
* @private
* @const
* @type Array.<number>
*/
PersianAlgoCal.monthLengths = [
31, // Farvardin
31, // Ordibehesht
31, // Khordad
31, // Tir
31, // Mordad
31, // Shahrivar
30, // Mehr
30, // Aban
30, // Azar
30, // Dey
30, // Bahman
29 // Esfand
];
/**
* Return the number of months in the given year. The number of months in a year varies
* for some luni-solar calendars because in some years, an extra month is needed to extend the
* days in a year to an entire solar year. The month is represented as a 1-based number
* where 1=first month, 2=second month, etc.
*
* @param {number} year a year for which the number of months is sought
* @return {number} The number of months in the given year
*/
PersianAlgoCal.prototype.getNumMonths = function(year) {
return 12;
};
/**
* Return the number of days in a particular month in a particular year. This function
* can return a different number for a month depending on the year because of things
* like leap years.
*
* @param {number} month the month for which the length is sought
* @param {number} year the year within which that month can be found
* @return {number} the number of days within the given month in the given year
*/
PersianAlgoCal.prototype.getMonLength = function(month, year) {
if (month !== 12 || !this.isLeapYear(year)) {
return PersianAlgoCal.monthLengths[month-1];
} else {
// Month 12, Esfand, has 30 days instead of 29 in leap years
return 30;
}
};
/**
* Return the equivalent year in the 2820 year cycle that begins on
* Far 1, 474. This particular cycle obeys the cycle-of-years formula
* whereas the others do not specifically. This cycle can be used as
* a proxy for other years outside of the cycle by shifting them into
* the cycle.
* @param {number} year year to find the equivalent cycle year for
* @returns {number} the equivalent cycle year
*/
PersianAlgoCal.prototype.equivalentCycleYear = function(year) {
var y = year - (year >= 0 ? 474 : 473);
return MathUtils.mod(y, 2820) + 474;
};
/**
* Return true if the given year is a leap year in the Persian calendar.
* The year parameter may be given as a number, or as a PersAlgoDate object.
* @param {number} year the year for which the leap year information is being sought
* @return {boolean} true if the given year is a leap year
*/
PersianAlgoCal.prototype.isLeapYear = function(year) {
return (MathUtils.mod((this.equivalentCycleYear(year) + 38) * 682, 2816) < 682);
};
/**
* Return the type of this calendar.
*
* @return {string} the name of the type of this calendar
*/
PersianAlgoCal.prototype.getType = function() {
return this.type;
};
/* register this calendar for the factory method */
Calendar._constructors["persian-algo"] = PersianAlgoCal;
module.exports = PersianAlgoCal;
Source