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   1  <?php
   2  
   3  /**
   4   * PHPExcel
   5   *
   6   * Copyright (c) 2006 - 2014 PHPExcel
   7   *
   8   * This library is free software; you can redistribute it and/or
   9   * modify it under the terms of the GNU Lesser General Public
  10   * License as published by the Free Software Foundation; either
  11   * version 2.1 of the License, or (at your option) any later version.
  12   *
  13   * This library is distributed in the hope that it will be useful,
  14   * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16   * Lesser General Public License for more details.
  17   *
  18   * You should have received a copy of the GNU Lesser General Public
  19   * License along with this library; if not, write to the Free Software
  20   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  21   *
  22   * @category   PHPExcel
  23   * @package    PHPExcel_Shared
  24   * @copyright  Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)
  25   * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
  26   * @version    ##VERSION##, ##DATE##
  27   */
  28  
  29  
  30  /**
  31   * PHPExcel_Shared_TimeZone
  32   *
  33   * @category   PHPExcel
  34   * @package    PHPExcel_Shared
  35   * @copyright  Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)
  36   */
  37  class PHPExcel_Shared_TimeZone
  38  {
  39      /*
  40       * Default Timezone used for date/time conversions
  41       *
  42       * @private
  43       * @var    string
  44       */
  45      protected static $_timezone    = 'UTC';
  46  
  47      /**
  48       * Validate a Timezone name
  49       *
  50       * @param     string        $timezone            Time zone (e.g. 'Europe/London')
  51       * @return     boolean                        Success or failure
  52       */
  53  	public static function _validateTimeZone($timezone) {
  54          if (in_array($timezone, DateTimeZone::listIdentifiers())) {
  55              return TRUE;
  56          }
  57          return FALSE;
  58      }
  59  
  60      /**
  61       * Set the Default Timezone used for date/time conversions
  62       *
  63       * @param     string        $timezone            Time zone (e.g. 'Europe/London')
  64       * @return     boolean                        Success or failure
  65       */
  66  	public static function setTimeZone($timezone) {
  67          if (self::_validateTimezone($timezone)) {
  68              self::$_timezone = $timezone;
  69              return TRUE;
  70          }
  71          return FALSE;
  72      }    //    function setTimezone()
  73  
  74  
  75      /**
  76       * Return the Default Timezone used for date/time conversions
  77       *
  78       * @return     string        Timezone (e.g. 'Europe/London')
  79       */
  80  	public static function getTimeZone() {
  81          return self::$_timezone;
  82      }    //    function getTimezone()
  83  
  84  
  85      /**
  86       *    Return the Timezone transition for the specified timezone and timestamp
  87       *
  88       *    @param        DateTimeZone         $objTimezone    The timezone for finding the transitions
  89       *    @param        integer                 $timestamp        PHP date/time value for finding the current transition
  90       *    @return         array                The current transition details
  91       */
  92  	private static function _getTimezoneTransitions($objTimezone, $timestamp) {
  93          $allTransitions = $objTimezone->getTransitions();
  94          $transitions = array();
  95          foreach($allTransitions as $key => $transition) {
  96              if ($transition['ts'] > $timestamp) {
  97                  $transitions[] = ($key > 0) ? $allTransitions[$key - 1] : $transition;
  98                  break;
  99              }
 100              if (empty($transitions)) {
 101                  $transitions[] = end($allTransitions);
 102              }
 103          }
 104  
 105          return $transitions;
 106      }
 107  
 108      /**
 109       *    Return the Timezone offset used for date/time conversions to/from UST
 110       *    This requires both the timezone and the calculated date/time to allow for local DST
 111       *
 112       *    @param        string                 $timezone        The timezone for finding the adjustment to UST
 113       *    @param        integer                 $timestamp        PHP date/time value
 114       *    @return         integer                Number of seconds for timezone adjustment
 115       *    @throws        PHPExcel_Exception
 116       */
 117  	public static function getTimeZoneAdjustment($timezone, $timestamp) {
 118          if ($timezone !== NULL) {
 119              if (!self::_validateTimezone($timezone)) {
 120                  throw new PHPExcel_Exception("Invalid timezone " . $timezone);
 121              }
 122          } else {
 123              $timezone = self::$_timezone;
 124          }
 125  
 126          if ($timezone == 'UST') {
 127              return 0;
 128          }
 129  
 130          $objTimezone = new DateTimeZone($timezone);
 131          if (version_compare(PHP_VERSION, '5.3.0') >= 0) {
 132              $transitions = $objTimezone->getTransitions($timestamp,$timestamp);
 133          } else {
 134              $transitions = self::_getTimezoneTransitions($objTimezone, $timestamp);
 135          }
 136  
 137          return (count($transitions) > 0) ? $transitions[0]['offset'] : 0;
 138      }
 139  
 140  }