nextcloud/core/js/jstz.js

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/**
* This script gives you the zone info key representing your device's time zone setting.
*
* @name jsTimezoneDetect
* @version 1.0.5
* @author Jon Nylander
* @license MIT License - http://www.opensource.org/licenses/mit-license.php
*
* For usage and examples, visit:
* http://pellepim.bitbucket.org/jstz/
*
* Copyright (c) Jon Nylander
*/
/*jslint undef: true */
/*global console, exports*/
(function(root) {
/**
* Namespace to hold all the code for timezone detection.
*/
var jstz = (function () {
'use strict';
var HEMISPHERE_SOUTH = 's',
/**
* Gets the offset in minutes from UTC for a certain date.
* @param {Date} date
* @returns {Number}
*/
get_date_offset = function (date) {
var offset = -date.getTimezoneOffset();
return (offset !== null ? offset : 0);
},
get_date = function (year, month, date) {
var d = new Date();
if (year !== undefined) {
d.setFullYear(year);
}
d.setMonth(month);
d.setDate(date);
return d;
},
get_january_offset = function (year) {
return get_date_offset(get_date(year, 0 ,2));
},
get_june_offset = function (year) {
return get_date_offset(get_date(year, 5, 2));
},
/**
* Private method.
* Checks whether a given date is in daylight saving time.
* If the date supplied is after august, we assume that we're checking
* for southern hemisphere DST.
* @param {Date} date
* @returns {Boolean}
*/
date_is_dst = function (date) {
var is_southern = date.getMonth() > 7,
base_offset = is_southern ? get_june_offset(date.getFullYear()) :
get_january_offset(date.getFullYear()),
date_offset = get_date_offset(date),
is_west = base_offset < 0,
dst_offset = base_offset - date_offset;
if (!is_west && !is_southern) {
return dst_offset < 0;
}
return dst_offset !== 0;
},
/**
* This function does some basic calculations to create information about
* the user's timezone. It uses REFERENCE_YEAR as a solid year for which
* the script has been tested rather than depend on the year set by the
* client device.
*
* Returns a key that can be used to do lookups in jstz.olson.timezones.
* eg: "720,1,2".
*
* @returns {String}
*/
lookup_key = function () {
var january_offset = get_january_offset(),
june_offset = get_june_offset(),
diff = january_offset - june_offset;
if (diff < 0) {
return january_offset + ",1";
} else if (diff > 0) {
return june_offset + ",1," + HEMISPHERE_SOUTH;
}
return january_offset + ",0";
},
/**
* Uses get_timezone_info() to formulate a key to use in the olson.timezones dictionary.
*
* Returns a primitive object on the format:
* {'timezone': TimeZone, 'key' : 'the key used to find the TimeZone object'}
*
* @returns Object
*/
determine = function () {
var key = lookup_key();
return new jstz.TimeZone(jstz.olson.timezones[key]);
},
/**
* This object contains information on when daylight savings starts for
* different timezones.
*
* The list is short for a reason. Often we do not have to be very specific
* to single out the correct timezone. But when we do, this list comes in
* handy.
*
* Each value is a date denoting when daylight savings starts for that timezone.
*/
dst_start_for = function (tz_name) {
var ru_pre_dst_change = new Date(2010, 6, 15, 1, 0, 0, 0), // In 2010 Russia had DST, this allows us to detect Russia :)
dst_starts = {
'America/Denver': new Date(2011, 2, 13, 3, 0, 0, 0),
'America/Mazatlan': new Date(2011, 3, 3, 3, 0, 0, 0),
'America/Chicago': new Date(2011, 2, 13, 3, 0, 0, 0),
'America/Mexico_City': new Date(2011, 3, 3, 3, 0, 0, 0),
'America/Asuncion': new Date(2012, 9, 7, 3, 0, 0, 0),
'America/Santiago': new Date(2012, 9, 3, 3, 0, 0, 0),
'America/Campo_Grande': new Date(2012, 9, 21, 5, 0, 0, 0),
'America/Montevideo': new Date(2011, 9, 2, 3, 0, 0, 0),
'America/Sao_Paulo': new Date(2011, 9, 16, 5, 0, 0, 0),
'America/Los_Angeles': new Date(2011, 2, 13, 8, 0, 0, 0),
'America/Santa_Isabel': new Date(2011, 3, 5, 8, 0, 0, 0),
'America/Havana': new Date(2012, 2, 10, 2, 0, 0, 0),
'America/New_York': new Date(2012, 2, 10, 7, 0, 0, 0),
'Europe/Helsinki': new Date(2013, 2, 31, 5, 0, 0, 0),
'Pacific/Auckland': new Date(2011, 8, 26, 7, 0, 0, 0),
'America/Halifax': new Date(2011, 2, 13, 6, 0, 0, 0),
'America/Goose_Bay': new Date(2011, 2, 13, 2, 1, 0, 0),
'America/Miquelon': new Date(2011, 2, 13, 5, 0, 0, 0),
'America/Godthab': new Date(2011, 2, 27, 1, 0, 0, 0),
'Europe/Moscow': ru_pre_dst_change,
'Asia/Amman': new Date(2013, 2, 29, 1, 0, 0, 0),
'Asia/Beirut': new Date(2013, 2, 31, 2, 0, 0, 0),
'Asia/Damascus': new Date(2013, 3, 6, 2, 0, 0, 0),
'Asia/Jerusalem': new Date(2013, 2, 29, 5, 0, 0, 0),
'Asia/Yekaterinburg': ru_pre_dst_change,
'Asia/Omsk': ru_pre_dst_change,
'Asia/Krasnoyarsk': ru_pre_dst_change,
'Asia/Irkutsk': ru_pre_dst_change,
'Asia/Yakutsk': ru_pre_dst_change,
'Asia/Vladivostok': ru_pre_dst_change,
'Asia/Baku': new Date(2013, 2, 31, 4, 0, 0),
'Asia/Yerevan': new Date(2013, 2, 31, 3, 0, 0),
'Asia/Kamchatka': ru_pre_dst_change,
'Asia/Gaza': new Date(2010, 2, 27, 4, 0, 0),
'Africa/Cairo': new Date(2010, 4, 1, 3, 0, 0),
'Europe/Minsk': ru_pre_dst_change,
'Pacific/Apia': new Date(2010, 10, 1, 1, 0, 0, 0),
'Pacific/Fiji': new Date(2010, 11, 1, 0, 0, 0),
'Australia/Perth': new Date(2008, 10, 1, 1, 0, 0, 0)
};
return dst_starts[tz_name];
};
return {
determine: determine,
date_is_dst: date_is_dst,
dst_start_for: dst_start_for
};
}());
/**
* Simple object to perform ambiguity check and to return name of time zone.
*/
jstz.TimeZone = function (tz_name) {
'use strict';
/**
* The keys in this object are timezones that we know may be ambiguous after
* a preliminary scan through the olson_tz object.
*
* The array of timezones to compare must be in the order that daylight savings
* starts for the regions.
*/
var AMBIGUITIES = {
'America/Denver': ['America/Denver', 'America/Mazatlan'],
'America/Chicago': ['America/Chicago', 'America/Mexico_City'],
'America/Santiago': ['America/Santiago', 'America/Asuncion', 'America/Campo_Grande'],
'America/Montevideo': ['America/Montevideo', 'America/Sao_Paulo'],
'Asia/Beirut': ['Asia/Amman', 'Asia/Jerusalem', 'Asia/Beirut', 'Europe/Helsinki','Asia/Damascus'],
'Pacific/Auckland': ['Pacific/Auckland', 'Pacific/Fiji'],
'America/Los_Angeles': ['America/Los_Angeles', 'America/Santa_Isabel'],
'America/New_York': ['America/Havana', 'America/New_York'],
'America/Halifax': ['America/Goose_Bay', 'America/Halifax'],
'America/Godthab': ['America/Miquelon', 'America/Godthab'],
'Asia/Dubai': ['Europe/Moscow'],
'Asia/Dhaka': ['Asia/Yekaterinburg'],
'Asia/Jakarta': ['Asia/Omsk'],
'Asia/Shanghai': ['Asia/Krasnoyarsk', 'Australia/Perth'],
'Asia/Tokyo': ['Asia/Irkutsk'],
'Australia/Brisbane': ['Asia/Yakutsk'],
'Pacific/Noumea': ['Asia/Vladivostok'],
'Pacific/Tarawa': ['Asia/Kamchatka', 'Pacific/Fiji'],
'Pacific/Tongatapu': ['Pacific/Apia'],
'Asia/Baghdad': ['Europe/Minsk'],
'Asia/Baku': ['Asia/Yerevan','Asia/Baku'],
'Africa/Johannesburg': ['Asia/Gaza', 'Africa/Cairo']
},
timezone_name = tz_name,
/**
* Checks if a timezone has possible ambiguities. I.e timezones that are similar.
*
* For example, if the preliminary scan determines that we're in America/Denver.
* We double check here that we're really there and not in America/Mazatlan.
*
* This is done by checking known dates for when daylight savings start for different
* timezones during 2010 and 2011.
*/
ambiguity_check = function () {
var ambiguity_list = AMBIGUITIES[timezone_name],
length = ambiguity_list.length,
i = 0,
tz = ambiguity_list[0];
for (; i < length; i += 1) {
tz = ambiguity_list[i];
if (jstz.date_is_dst(jstz.dst_start_for(tz))) {
timezone_name = tz;
return;
}
}
},
/**
* Checks if it is possible that the timezone is ambiguous.
*/
is_ambiguous = function () {
return typeof (AMBIGUITIES[timezone_name]) !== 'undefined';
};
if (is_ambiguous()) {
ambiguity_check();
}
return {
name: function () {
return timezone_name;
}
};
};
jstz.olson = {};
/*
* The keys in this dictionary are comma separated as such:
*
* First the offset compared to UTC time in minutes.
*
* Then a flag which is 0 if the timezone does not take daylight savings into account and 1 if it
* does.
*
* Thirdly an optional 's' signifies that the timezone is in the southern hemisphere,
* only interesting for timezones with DST.
*
* The mapped arrays is used for constructing the jstz.TimeZone object from within
* jstz.determine_timezone();
*/
jstz.olson.timezones = {
'-720,0' : 'Pacific/Majuro',
'-660,0' : 'Pacific/Pago_Pago',
'-600,1' : 'America/Adak',
'-600,0' : 'Pacific/Honolulu',
'-570,0' : 'Pacific/Marquesas',
'-540,0' : 'Pacific/Gambier',
'-540,1' : 'America/Anchorage',
'-480,1' : 'America/Los_Angeles',
'-480,0' : 'Pacific/Pitcairn',
'-420,0' : 'America/Phoenix',
'-420,1' : 'America/Denver',
'-360,0' : 'America/Guatemala',
'-360,1' : 'America/Chicago',
'-360,1,s' : 'Pacific/Easter',
'-300,0' : 'America/Bogota',
'-300,1' : 'America/New_York',
'-270,0' : 'America/Caracas',
'-240,1' : 'America/Halifax',
'-240,0' : 'America/Santo_Domingo',
'-240,1,s' : 'America/Santiago',
'-210,1' : 'America/St_Johns',
'-180,1' : 'America/Godthab',
'-180,0' : 'America/Argentina/Buenos_Aires',
'-180,1,s' : 'America/Montevideo',
'-120,0' : 'America/Noronha',
'-120,1' : 'America/Noronha',
'-60,1' : 'Atlantic/Azores',
'-60,0' : 'Atlantic/Cape_Verde',
'0,0' : 'UTC',
'0,1' : 'Europe/London',
'60,1' : 'Europe/Berlin',
'60,0' : 'Africa/Lagos',
'60,1,s' : 'Africa/Windhoek',
'120,1' : 'Asia/Beirut',
'120,0' : 'Africa/Johannesburg',
'180,0' : 'Asia/Baghdad',
'180,1' : 'Europe/Moscow',
'210,1' : 'Asia/Tehran',
'240,0' : 'Asia/Dubai',
'240,1' : 'Asia/Baku',
'270,0' : 'Asia/Kabul',
'300,1' : 'Asia/Yekaterinburg',
'300,0' : 'Asia/Karachi',
'330,0' : 'Asia/Kolkata',
'345,0' : 'Asia/Kathmandu',
'360,0' : 'Asia/Dhaka',
'360,1' : 'Asia/Omsk',
'390,0' : 'Asia/Rangoon',
'420,1' : 'Asia/Krasnoyarsk',
'420,0' : 'Asia/Jakarta',
'480,0' : 'Asia/Shanghai',
'480,1' : 'Asia/Irkutsk',
'525,0' : 'Australia/Eucla',
'525,1,s' : 'Australia/Eucla',
'540,1' : 'Asia/Yakutsk',
'540,0' : 'Asia/Tokyo',
'570,0' : 'Australia/Darwin',
'570,1,s' : 'Australia/Adelaide',
'600,0' : 'Australia/Brisbane',
'600,1' : 'Asia/Vladivostok',
'600,1,s' : 'Australia/Sydney',
'630,1,s' : 'Australia/Lord_Howe',
'660,1' : 'Asia/Kamchatka',
'660,0' : 'Pacific/Noumea',
'690,0' : 'Pacific/Norfolk',
'720,1,s' : 'Pacific/Auckland',
'720,0' : 'Pacific/Tarawa',
'765,1,s' : 'Pacific/Chatham',
'780,0' : 'Pacific/Tongatapu',
'780,1,s' : 'Pacific/Apia',
'840,0' : 'Pacific/Kiritimati'
};
if (typeof exports !== 'undefined') {
exports.jstz = jstz;
} else {
root.jstz = jstz;
}
})(this);