<?php
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namespace PhpOffice\PhpSpreadsheet\Shared;
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use DateTimeZone;
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use PhpOffice\PhpSpreadsheet\Exception as PhpSpreadsheetException;
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class TimeZone
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{
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/**
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* Default Timezone used for date/time conversions.
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*
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* @var string
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*/
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protected static $timezone = 'UTC';
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/**
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* Validate a Timezone name.
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*
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* @param string $timezone Time zone (e.g. 'Europe/London')
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*
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* @return bool Success or failure
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*/
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private static function validateTimeZone($timezone)
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{
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return in_array($timezone, DateTimeZone::listIdentifiers());
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}
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/**
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* Set the Default Timezone used for date/time conversions.
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*
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* @param string $timezone Time zone (e.g. 'Europe/London')
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*
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* @return bool Success or failure
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*/
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public static function setTimeZone($timezone)
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{
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if (self::validateTimezone($timezone)) {
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self::$timezone = $timezone;
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return true;
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}
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return false;
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}
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/**
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* Return the Default Timezone used for date/time conversions.
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*
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* @return string Timezone (e.g. 'Europe/London')
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*/
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public static function getTimeZone()
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{
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return self::$timezone;
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}
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/**
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* Return the Timezone offset used for date/time conversions to/from UST
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* This requires both the timezone and the calculated date/time to allow for local DST.
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*
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* @param string $timezone The timezone for finding the adjustment to UST
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* @param int $timestamp PHP date/time value
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*
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* @throws PhpSpreadsheetException
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*
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* @return int Number of seconds for timezone adjustment
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*/
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public static function getTimeZoneAdjustment($timezone, $timestamp)
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{
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if ($timezone !== null) {
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if (!self::validateTimezone($timezone)) {
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throw new PhpSpreadsheetException('Invalid timezone ' . $timezone);
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}
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} else {
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$timezone = self::$timezone;
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}
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if ($timezone == 'UST') {
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return 0;
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}
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$objTimezone = new DateTimeZone($timezone);
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$transitions = $objTimezone->getTransitions($timestamp, $timestamp);
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return (count($transitions) > 0) ? $transitions[0]['offset'] : 0;
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}
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}
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