init

lib/PhpSpreadsheet/Shared/TimeZone.php

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