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 1.8.0, 2014-03-02
 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: }
141: