/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview Functions to provide timezone information for use with
* date/time format.
*/
goog.provide('goog.i18n.TimeZone');
goog.require('goog.array');
/**
* @suppress {extraRequire} goog.date.DateLike represents a Date or a
* goog.Date object. It is a parameter in the following methods:
* - getDaylightAdjustment
* - getGMTString
* - getLongName
* - getOffset
* - getRFCTimeZoneString
* - getShortName
* - getUTCString
* - isDaylightTime
* - getLongNameGMT
* - getGenericLocation
* Lint warns that this require is unnecessary but the closure compiler needs
* it in order to accept a Date or a goog.Date object as a goog.date.DateLike
* parameter in any of these methods.
*/
goog.require('goog.date.DateLike');
goog.require('goog.object');
goog.require('goog.string');
/**
* TimeZone class implemented a time zone resolution and name information
* source for client applications. The time zone object is initiated from
* a time zone information object. Application can initiate a time zone
* statically, or it may choose to initiate from a data obtained from server.
* Each time zone information array is small, but the whole set of data
* is too much for client application to download. If end user is allowed to
* change time zone setting, dynamic retrieval should be the method to use.
* In case only time zone offset is known, there is a decent fallback
* that only use the time zone offset to create a TimeZone object.
*
* @constructor
* @final
*/
goog.i18n.TimeZone = function() {
'use strict';
/**
* The standard time zone id.
* @type {string}
* @private
*/
this.timeZoneId_;
/**
* The standard, non-daylight time zone offset, in minutes WEST of UTC.
* @type {number}
* @private
*/
this.standardOffset_;
/**
* An array of strings that can have 2 or 4 elements. The first two elements
* are the long and short names for standard time in this time zone, and the
* last two elements (if present) are the long and short names for daylight
* time in this time zone.
* @type {Array<string>}
* @private
*/
this.tzNames_;
/**
* An object of 2 to 4 elements. The STD_* are always available, while the
* DST_* are only available when daylight saving time is available for this
* time zone.
* <ul>
* <li>STD_LONG_NAME_GMT: long GMT name for standard time</li>
* <li>STD_GENERIC_LOCATION: generic location for standard time</li>
* <li>DST_LONG_NAME_GMT: long GMT for daylight saving time</li>
* <li>DST_GENERIC_LOCATION: generic location for daylight saving time</li>
* </ul>
* @type {{
* STD_LONG_NAME_GMT: string,
* STD_GENERIC_LOCATION: string,
* DST_LONG_NAME_GMT: (string|undefined),
* DST_GENERIC_LOCATION: (string|undefined)
* }}
* @private
*/
this.tzNamesExt_;
/**
* This array specifies the Daylight Saving Time transitions for this time
* zone. This is a flat array of numbers which are interpreted in pairs:
* [time1, adjustment1, time2, adjustment2, ...] where each time is a DST
* transition point given as a number of hours since 00:00 UTC, January 1,
* 1970, and each adjustment is the adjustment to apply for times after the
* DST transition, given as minutes EAST of UTC.
* @type {Array<number>}
* @private
*/
this.transitions_;
};
/**
* The number of milliseconds in an hour.
* @type {number}
* @private
*/
goog.i18n.TimeZone.MILLISECONDS_PER_HOUR_ = 3600 * 1000;
/**
* Indices into the array of time zone names.
* @enum {number}
*/
goog.i18n.TimeZone.NameType = {
STD_SHORT_NAME: 0,
STD_LONG_NAME: 1,
DLT_SHORT_NAME: 2,
DLT_LONG_NAME: 3
};
/**
* This factory method creates a time zone instance. It takes either an object
* containing complete time zone information, or a single number representing a
* constant time zone offset. If the latter form is used, DST functionality is
* not available.
*
* @param {number|Object} timeZoneData If this parameter is a number, it should
* indicate minutes WEST of UTC to be used as a constant time zone offset.
* Otherwise, it should be an object with these four fields:
* <ul>
* <li>id: A string ID for the time zone.
* <li>std_offset: The standard time zone offset in minutes EAST of UTC.
* <li>names: An array of four names (standard short name, standard long
* name, daylight short name, daylight long, name)
* <li>names_ext: A hash of four fields (standard long name gmt, daylight
* long name gmt, standard generic location, daylight generic
* location)
* <li>transitions: An array of numbers which are interpreted in pairs:
* [time1, adjustment1, time2, adjustment2, ...] where each time is
* a DST transition point given as a number of hours since 00:00 UTC,
* January 1, 1970, and each adjustment is the adjustment to apply
* for times after the DST transition, given as minutes EAST of UTC.
* </ul>
* @return {!goog.i18n.TimeZone} A goog.i18n.TimeZone object for the given
* time zone data.
*/
goog.i18n.TimeZone.createTimeZone = function(timeZoneData) {
'use strict';
if (typeof timeZoneData == 'number') {
return goog.i18n.TimeZone.createSimpleTimeZone_(timeZoneData);
}
var tz = new goog.i18n.TimeZone();
tz.timeZoneId_ = timeZoneData['id'];
tz.standardOffset_ = -timeZoneData['std_offset'];
tz.tzNames_ = timeZoneData['names'];
tz.tzNamesExt_ = timeZoneData['names_ext'];
tz.transitions_ = timeZoneData['transitions'];
return tz;
};
/**
* This factory method creates a time zone object with a constant offset.
* @param {number} timeZoneOffsetInMinutes Offset in minutes WEST of UTC.
* @return {!goog.i18n.TimeZone} A time zone object with the given constant
* offset. Note that the time zone ID of this object will use the POSIX
* convention, which has a reversed sign ("Etc/GMT+8" means UTC-8 or PST).
* @private
*/
goog.i18n.TimeZone.createSimpleTimeZone_ = function(timeZoneOffsetInMinutes) {
'use strict';
var tz = new goog.i18n.TimeZone();
tz.standardOffset_ = timeZoneOffsetInMinutes;
tz.timeZoneId_ =
goog.i18n.TimeZone.composePosixTimeZoneID_(timeZoneOffsetInMinutes);
var str = goog.i18n.TimeZone.composeUTCString_(timeZoneOffsetInMinutes);
var strGMT = goog.i18n.TimeZone.composeGMTString_(timeZoneOffsetInMinutes);
tz.tzNames_ = [str, str];
tz.tzNamesExt_ = {STD_LONG_NAME_GMT: strGMT, STD_GENERIC_LOCATION: strGMT};
tz.transitions_ = [];
return tz;
};
/**
* Generate a GMT-relative string for a constant time zone offset.
* @param {number} offset The time zone offset in minutes WEST of UTC.
* @return {string} The GMT string for this offset, which will indicate
* hours EAST of UTC.
* @private
*/
goog.i18n.TimeZone.composeGMTString_ = function(offset) {
'use strict';
var parts = ['GMT'];
parts.push(offset <= 0 ? '+' : '-');
offset = Math.abs(offset);
parts.push(
goog.string.padNumber(Math.floor(offset / 60) % 100, 2), ':',
goog.string.padNumber(offset % 60, 2));
return parts.join('');
};
/**
* Generate a POSIX time zone ID for a constant time zone offset.
* @param {number} offset The time zone offset in minutes WEST of UTC.
* @return {string} The POSIX time zone ID for this offset, which will indicate
* hours WEST of UTC.
* @private
*/
goog.i18n.TimeZone.composePosixTimeZoneID_ = function(offset) {
'use strict';
if (offset == 0) {
return 'Etc/GMT';
}
var parts = ['Etc/GMT', offset < 0 ? '-' : '+'];
offset = Math.abs(offset);
parts.push(Math.floor(offset / 60) % 100);
offset = offset % 60;
if (offset != 0) {
parts.push(':', goog.string.padNumber(offset, 2));
}
return parts.join('');
};
/**
* Generate a UTC-relative string for a constant time zone offset.
* @param {number} offset The time zone offset in minutes WEST of UTC.
* @return {string} The UTC string for this offset, which will indicate
* hours EAST of UTC.
* @private
*/
goog.i18n.TimeZone.composeUTCString_ = function(offset) {
'use strict';
if (offset == 0) {
return 'UTC';
}
var parts = ['UTC', offset < 0 ? '+' : '-'];
offset = Math.abs(offset);
parts.push(Math.floor(offset / 60) % 100);
offset = offset % 60;
if (offset != 0) {
parts.push(':', offset);
}
return parts.join('');
};
/**
* Convert the contents of time zone object to a timeZoneData object, suitable
* for passing to goog.i18n.TimeZone.createTimeZone.
* @return {!Object} A timeZoneData object (see the documentation for
* goog.i18n.TimeZone.createTimeZone).
*/
goog.i18n.TimeZone.prototype.getTimeZoneData = function() {
'use strict';
return {
'id': this.timeZoneId_,
'std_offset': -this.standardOffset_, // note createTimeZone flips the sign
'names': goog.array.clone(this.tzNames_), // avoid aliasing the array
'names_ext': goog.object.clone(this.tzNamesExt_), // avoid aliasing
'transitions': goog.array.clone(this.transitions_) // avoid aliasing
};
};
/**
* Return the DST adjustment to the time zone offset for a given time.
* While Daylight Saving Time is in effect, this number is positive.
* Otherwise, it is zero.
* @param {goog.date.DateLike} date The time to check.
* @return {number} The DST adjustment in minutes EAST of UTC.
*/
goog.i18n.TimeZone.prototype.getDaylightAdjustment = function(date) {
'use strict';
var timeInMs = Date.UTC(
date.getUTCFullYear(), date.getUTCMonth(), date.getUTCDate(),
date.getUTCHours(), date.getUTCMinutes());
var timeInHours = timeInMs / goog.i18n.TimeZone.MILLISECONDS_PER_HOUR_;
var index = 0;
while (index < this.transitions_.length &&
timeInHours >= this.transitions_[index]) {
index += 2;
}
return (index == 0) ? 0 : this.transitions_[index - 1];
};
/**
* Return the GMT representation of this time zone object.
* @param {goog.date.DateLike} date The date for which time to retrieve
* GMT string.
* @return {string} GMT representation string.
*/
goog.i18n.TimeZone.prototype.getGMTString = function(date) {
'use strict';
return goog.i18n.TimeZone.composeGMTString_(this.getOffset(date));
};
/**
* Return the UTC representation of this time zone object.
* @param {!goog.date.DateLike} date The date for which time to retrieve
* UTC string.
* @return {string} UTC representation string.
*/
goog.i18n.TimeZone.prototype.getUTCString = function(date) {
'use strict';
return goog.i18n.TimeZone.composeUTCString_(this.getOffset(date));
};
/**
* Get the long time zone name for a given date/time.
* @param {goog.date.DateLike} date The time for which to retrieve
* the long time zone name.
* @return {string} The long time zone name.
*/
goog.i18n.TimeZone.prototype.getLongName = function(date) {
'use strict';
return this.tzNames_[this.isDaylightTime(date) ?
goog.i18n.TimeZone.NameType.DLT_LONG_NAME :
goog.i18n.TimeZone.NameType.STD_LONG_NAME];
};
/**
* Get the time zone offset in minutes WEST of UTC for a given date/time.
* @param {goog.date.DateLike} date The time for which to retrieve
* the time zone offset.
* @return {number} The time zone offset in minutes WEST of UTC.
*/
goog.i18n.TimeZone.prototype.getOffset = function(date) {
'use strict';
return this.standardOffset_ - this.getDaylightAdjustment(date);
};
/**
* Get the RFC representation of the time zone for a given date/time.
* @param {goog.date.DateLike} date The time for which to retrieve the
* RFC time zone string.
* @return {string} The RFC time zone string.
*/
goog.i18n.TimeZone.prototype.getRFCTimeZoneString = function(date) {
'use strict';
var offset = -this.getOffset(date);
var parts = [offset < 0 ? '-' : '+'];
offset = Math.abs(offset);
parts.push(
goog.string.padNumber(Math.floor(offset / 60) % 100, 2),
goog.string.padNumber(offset % 60, 2));
return parts.join('');
};
/**
* Get the short time zone name for given date/time.
* @param {goog.date.DateLike} date The time for which to retrieve
* the short time zone name.
* @return {string} The short time zone name.
*/
goog.i18n.TimeZone.prototype.getShortName = function(date) {
'use strict';
return this.tzNames_[this.isDaylightTime(date) ?
goog.i18n.TimeZone.NameType.DLT_SHORT_NAME :
goog.i18n.TimeZone.NameType.STD_SHORT_NAME];
};
/**
* Return the time zone ID for this time zone.
* @return {string} The time zone ID.
*/
goog.i18n.TimeZone.prototype.getTimeZoneId = function() {
'use strict';
return this.timeZoneId_;
};
/**
* Check if Daylight Saving Time is in effect at a given time in this time zone.
* @param {goog.date.DateLike} date The time to check.
* @return {boolean} True if Daylight Saving Time is in effect.
*/
goog.i18n.TimeZone.prototype.isDaylightTime = function(date) {
'use strict';
return this.getDaylightAdjustment(date) > 0;
};
/**
* Get the long GMT time zone name for a given date/time.
* @param {!goog.date.DateLike} date The time for which to retrieve
* the long GMT time zone name.
* @return {string} The long GMT time zone name.
*/
goog.i18n.TimeZone.prototype.getLongNameGMT = function(date) {
'use strict';
if (this.isDaylightTime(date)) {
return (this.tzNamesExt_.DST_LONG_NAME_GMT !== undefined) ?
this.tzNamesExt_.DST_LONG_NAME_GMT :
this.tzNamesExt_['DST_LONG_NAME_GMT'];
} else {
return (this.tzNamesExt_.STD_LONG_NAME_GMT !== undefined) ?
this.tzNamesExt_.STD_LONG_NAME_GMT :
this.tzNamesExt_['STD_LONG_NAME_GMT'];
}
};
/**
* Get the generic location time zone name for a given date/time.
* @param {!goog.date.DateLike} date The time for which to retrieve
* the generic location time zone name.
* @return {string} The generic location time zone name.
*/
goog.i18n.TimeZone.prototype.getGenericLocation = function(date) {
'use strict';
if (this.isDaylightTime(date)) {
return (this.tzNamesExt_.DST_GENERIC_LOCATION !== undefined) ?
this.tzNamesExt_.DST_GENERIC_LOCATION :
this.tzNamesExt_['DST_GENERIC_LOCATION'];
} else {
return (this.tzNamesExt_.STD_GENERIC_LOCATION !== undefined) ?
this.tzNamesExt_.STD_GENERIC_LOCATION :
this.tzNamesExt_['STD_GENERIC_LOCATION'];
}
};
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