lib/classes/date.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * Core date and time related code.
  19  *
  20  * @package   core
  21  * @copyright 2015 Totara Learning Solutions Ltd {@link http://www.totaralms.com/}
  22  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23  * @author    Petr Skoda <petr.skoda@totaralms.com>
  24  */
  25
  26 /**
  27  * Core date and time related code.
  28  *
  29  * @since Moodle 2.9
  30  * @package   core
  31  * @copyright 2015 Totara Learning Solutions Ltd {@link http://www.totaralms.com/}
  32  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  33  * @author    Petr Skoda <petr.skoda@totaralms.com>
  34  */
  35 class core_date {
  36     /** @var array list of recommended zones */
  37     protected static $goodzones = null;
  38
  39     /** @var array list of BC zones supported by PHP */
  40     protected static $bczones = null;
  41
  42     /** @var array mapping of timezones not supported by PHP */
  43     protected static $badzones = null;
  44
  45     /** @var string the default PHP timezone right after config.php */
  46     protected static $defaultphptimezone = null;
  47
  48     /**
  49      * Returns a localised list of timezones.
  50      * @param string $currentvalue
  51      * @param bool $include99 should the server timezone info be included?
  52      * @return array
  53      */
  54     public static function get_list_of_timezones($currentvalue = null, $include99 = false) {
  55         self::init_zones();
  56
  57         // Localise first.
  58         $timezones = array();
  59         foreach (self::$goodzones as $tzkey => $ignored) {
  60             $timezones[$tzkey] = self::get_localised_timezone($tzkey);
  61         }
  62         core_collator::asort($timezones);
  63
  64         // Add '99' if requested.
  65         if ($include99 or $currentvalue == 99) {
  66             $timezones['99'] = self::get_localised_timezone('99');
  67         }
  68
  69         if (!isset($currentvalue) or isset($timezones[$currentvalue])) {
  70             return $timezones;
  71         }
  72
  73         if (is_numeric($currentvalue)) {
  74             // UTC offset.
  75             if ($currentvalue == 0) {
  76                 $a = 'UTC';
  77             } else {
  78                 $modifier = ($currentvalue > 0) ? '+' : '';
  79                 $a = 'UTC' . $modifier . number_format($currentvalue, 1);
  80             }
  81             $timezones[$currentvalue] = get_string('timezoneinvalid', 'core_admin', $a);
  82         } else {
  83             // Some string we don't recognise.
  84             $timezones[$currentvalue] = get_string('timezoneinvalid', 'core_admin', $currentvalue);
  85         }
  86
  87         return $timezones;
  88     }
  89
  90     /**
  91      * Returns localised timezone name.
  92      * @param string $tz
  93      * @return string
  94      */
  95     public static function get_localised_timezone($tz) {
  96         if ($tz == 99) {
  97             $tz = self::get_server_timezone();
  98             $tz = self::get_localised_timezone($tz);
  99             return get_string('timezoneserver', 'core_admin', $tz);
 100         }
 101
 102         if (get_string_manager()->string_exists(strtolower($tz), 'core_timezones')) {
 103             $tz = get_string(strtolower($tz), 'core_timezones');
 104         } else if ($tz === 'GMT' or $tz === 'Etc/GMT' or $tz === 'Etc/UTC') {
 105             $tz = 'UTC';
 106         } else if (preg_match('|^Etc/GMT([+-])([0-9]+)$|', $tz, $matches)) {
 107             $sign = $matches[1] === '+' ? '-' : '+';
 108             $tz = 'UTC' . $sign . $matches[2];
 109         }
 110
 111         return $tz;
 112     }
 113
 114     /**
 115      * Normalise the timezone name. If timezone not supported
 116      * this method falls back to server timezone (if valid)
 117      * or default PHP timezone.
 118      *
 119      * @param int|string|float|DateTimeZone $tz
 120      * @return string timezone compatible with PHP
 121      */
 122     public static function normalise_timezone($tz) {
 123         global $CFG;
 124
 125         if ($tz instanceof DateTimeZone) {
 126             return $tz->getName();
 127         }
 128
 129         self::init_zones();
 130         $tz = (string)$tz;
 131
 132         if (isset(self::$goodzones[$tz]) or isset(self::$bczones[$tz])) {
 133             return $tz;
 134         }
 135
 136         $fixed = false;
 137         if (isset(self::$badzones[$tz])) {
 138             // Convert to known zone.
 139             $tz = self::$badzones[$tz];
 140             $fixed = true;
 141         } else if (is_numeric($tz)) {
 142             // Half hour numeric offsets were already tested, try rounding to integers here.
 143             $roundedtz = (string)(int)$tz;
 144             if (isset(self::$badzones[$roundedtz])) {
 145                 $tz = self::$badzones[$roundedtz];
 146                 $fixed = true;
 147             }
 148         }
 149
 150         if ($fixed and isset(self::$goodzones[$tz]) or isset(self::$bczones[$tz])) {
 151             return $tz;
 152         }
 153
 154         // Is server timezone usable?
 155         if (isset($CFG->timezone) and !is_numeric($CFG->timezone)) {
 156             $result = @timezone_open($CFG->timezone); // Hide notices if invalid.
 157             if ($result !== false) {
 158                 return $result->getName();
 159             }
 160         }
 161
 162         // Bad luck, use the php.ini default or value set in config.php.
 163         return self::get_default_php_timezone();
 164     }
 165
 166     /**
 167      * Returns server timezone.
 168      * @return string normalised timezone name compatible with PHP
 169      **/
 170     public static function get_server_timezone() {
 171         global $CFG;
 172
 173         if (!isset($CFG->timezone) or $CFG->timezone == 99 or $CFG->timezone === '') {
 174             return self::get_default_php_timezone();
 175         }
 176
 177         return self::normalise_timezone($CFG->timezone);
 178     }
 179
 180     /**
 181      * Returns server timezone.
 182      * @return DateTimeZone
 183      **/
 184     public static function get_server_timezone_object() {
 185         $tz = self::get_server_timezone();
 186         return new DateTimeZone($tz);
 187     }
 188
 189     /**
 190      * Set PHP default timezone to $CFG->timezone.
 191      */
 192     public static function set_default_server_timezone() {
 193         global $CFG;
 194
 195         if (!isset($CFG->timezone) or $CFG->timezone == 99 or $CFG->timezone === '') {
 196             date_default_timezone_set(self::get_default_php_timezone());
 197             return;
 198         }
 199
 200         $current = date_default_timezone_get();
 201         if ($current === $CFG->timezone) {
 202             // Nothing to do.
 203             return;
 204         }
 205
 206         if (!isset(self::$goodzones)) {
 207             // For better performance try do do this without full tz init,
 208             // because this is called from lib/setup.php file on each page.
 209             $result = @timezone_open($CFG->timezone); // Ignore error if setting invalid.
 210             if ($result !== false) {
 211                 date_default_timezone_set($result->getName());
 212                 return;
 213             }
 214         }
 215
 216         // Slow way is the last option.
 217         date_default_timezone_set(self::get_server_timezone());
 218     }
 219
 220     /**
 221      * Returns user timezone.
 222      *
 223      * Ideally the parameter should be a real user record,
 224      * unfortunately the legacy code is using 99 for both server
 225      * and default value.
 226      *
 227      * Example of using legacy API:
 228      *    // Date for other user via legacy API.
 229      *    $datestr = userdate($time, core_date::get_user_timezone($user));
 230      *
 231      * The coding style rules in Moodle are moronic,
 232      * why cannot the parameter names have underscores in them?
 233      *
 234      * @param mixed $userorforcedtz user object or legacy forced timezone string or tz object
 235      * @return string normalised timezone name compatible with PHP
 236      */
 237     public static function get_user_timezone($userorforcedtz = null) {
 238         global $USER, $CFG;
 239
 240         if ($userorforcedtz instanceof DateTimeZone) {
 241             return $userorforcedtz->getName();
 242         }
 243
 244         if (isset($userorforcedtz) and !is_object($userorforcedtz) and $userorforcedtz != 99) {
 245             // Legacy code is forcing timezone in legacy API.
 246             return self::normalise_timezone($userorforcedtz);
 247         }
 248
 249         if (isset($CFG->forcetimezone) and $CFG->forcetimezone != 99) {
 250             // Override any user timezone.
 251             return self::normalise_timezone($CFG->forcetimezone);
 252         }
 253
 254         if ($userorforcedtz === null) {
 255             $tz = isset($USER->timezone) ? $USER->timezone : 99;
 256
 257         } else if (is_object($userorforcedtz)) {
 258             $tz = isset($userorforcedtz->timezone) ? $userorforcedtz->timezone : 99;
 259
 260         } else {
 261             if ($userorforcedtz == 99) {
 262                 $tz = isset($USER->timezone) ? $USER->timezone : 99;
 263             } else {
 264                 $tz = $userorforcedtz;
 265             }
 266         }
 267
 268         if ($tz == 99) {
 269             return self::get_server_timezone();
 270         }
 271
 272         return self::normalise_timezone($tz);
 273     }
 274
 275     /**
 276      * Return user timezone object.
 277      *
 278      * @param mixed $userorforcedtz
 279      * @return DateTimeZone
 280      */
 281     public static function get_user_timezone_object($userorforcedtz = null) {
 282         $tz = self::get_user_timezone($userorforcedtz);
 283         return new DateTimeZone($tz);
 284     }
 285
 286     /**
 287      * Return default timezone set in php.ini or config.php.
 288      * @return string normalised timezone compatible with PHP
 289      */
 290     public static function get_default_php_timezone() {
 291         if (!isset(self::$defaultphptimezone)) {
 292             // This should not happen.
 293             self::store_default_php_timezone();
 294         }
 295
 296         return self::$defaultphptimezone;
 297     }
 298
 299     /**
 300      * To be called from lib/setup.php only!
 301      */
 302     public static function store_default_php_timezone() {
 303         if ((defined('PHPUNIT_TEST') and PHPUNIT_TEST)
 304             or defined('BEHAT_SITE_RUNNING') or defined('BEHAT_TEST') or defined('BEHAT_UTIL')) {
 305             // We want all test sites to be consistent by default.
 306             self::$defaultphptimezone = 'Australia/Perth';
 307             return;
 308         }
 309         if (!isset(self::$defaultphptimezone)) {
 310             self::$defaultphptimezone = date_default_timezone_get();
 311         }
 312     }
 313
 314     /**
 315      * Do not use directly - use $this->setTimezone('xx', $tz) instead in your test case.
 316      * @param string $tz valid timezone name
 317      */
 318     public static function phpunit_override_default_php_timezone($tz) {
 319         if (!defined('PHPUNIT_TEST')) {
 320             throw new coding_exception('core_date::phpunit_override_default_php_timezone() must be used only from unit tests');
 321         }
 322         $result = timezone_open($tz); // This triggers error if $tz invalid.
 323         if ($result !== false) {
 324             self::$defaultphptimezone = $tz;
 325         } else {
 326             self::$defaultphptimezone = 'Australia/Perth';
 327         }
 328     }
 329
 330     /**
 331      * To be called from phpunit reset only, after restoring $CFG.
 332      */
 333     public static function phpunit_reset() {
 334         global $CFG;
 335         if (!defined('PHPUNIT_TEST')) {
 336             throw new coding_exception('core_date::phpunit_reset() must be used only from unit tests');
 337         }
 338         self::store_default_php_timezone();
 339         date_default_timezone_set($CFG->timezone);
 340     }
 341
 342     /**
 343      * Initialise timezone arrays, call before use.
 344      */
 345     protected static function init_zones() {
 346         if (isset(self::$goodzones)) {
 347             return;
 348         }
 349
 350         $zones = DateTimeZone::listIdentifiers();
 351         self::$goodzones = array_fill_keys($zones, true);
 352
 353         $zones = DateTimeZone::listIdentifiers(DateTimeZone::ALL_WITH_BC);
 354         self::$bczones = array();
 355         foreach ($zones as $zone) {
 356             if (isset(self::$goodzones[$zone])) {
 357                 continue;
 358             }
 359             self::$bczones[$zone] = true;
 360         }
 361
 362         self::$badzones = array(
 363             // Windows time zones.
 364             'Dateline Standard Time' => 'Etc/GMT+12',
 365             'Hawaiian Standard Time' => 'Pacific/Honolulu',
 366             'Alaskan Standard Time' => 'America/Anchorage',
 367             'Pacific Standard Time (Mexico)' => 'America/Tijuana',
 368             'Pacific Standard Time' => 'America/Los_Angeles',
 369             'US Mountain Standard Time' => 'America/Phoenix',
 370             'Mountain Standard Time (Mexico)' => 'America/Chihuahua',
 371             'Mountain Standard Time' => 'America/Denver',
 372             'Central America Standard Time' => 'America/Guatemala',
 373             'Central Standard Time' => 'America/Chicago',
 374             'Central Standard Time (Mexico)' => 'America/Mexico_City',
 375             'Canada Central Standard Time' => 'America/Regina',
 376             'SA Pacific Standard Time' => 'America/Bogota',
 377             'S.A. Pacific Standard Time' => 'America/Bogota',
 378             'Eastern Standard Time' => 'America/New_York',
 379             'US Eastern Standard Time' => 'America/Indiana/Indianapolis',
 380             'U.S. Eastern Standard Time' => 'America/Indiana/Indianapolis',
 381             'Venezuela Standard Time' => 'America/Caracas',
 382             'Paraguay Standard Time' => 'America/Asuncion',
 383             'Atlantic Standard Time' => 'America/Halifax',
 384             'Central Brazilian Standard Time' => 'America/Cuiaba',
 385             'SA Western Standard Time' => 'America/La_Paz',
 386             'S.A. Western Standard Time' => 'America/La_Paz',
 387             'Pacific SA Standard Time' => 'America/Santiago',
 388             'Pacific S.A. Standard Time' => 'America/Santiago',
 389             'Newfoundland Standard Time' => 'America/St_Johns',
 390             'Newfoundland and Labrador Standard Time' => 'America/St_Johns',
 391             'E. South America Standard Time' => 'America/Sao_Paulo',
 392             'Argentina Standard Time' => 'America/Argentina/Buenos_Aires',
 393             'SA Eastern Standard Time' => 'America/Cayenne',
 394             'S.A. Eastern Standard Time' => 'America/Cayenne',
 395             'Greenland Standard Time' => 'America/Godthab',
 396             'Montevideo Standard Time' => 'America/Montevideo',
 397             'Bahia Standard Time' => 'America/Bahia',
 398             'Azores Standard Time' => 'Atlantic/Azores',
 399             'Cape Verde Standard Time' => 'Atlantic/Cape_Verde',
 400             'Morocco Standard Time' => 'Africa/Casablanca',
 401             'GMT Standard Time' => 'Europe/London',
 402             'Greenwich Standard Time' => 'Atlantic/Reykjavik',
 403             'W. Europe Standard Time' => 'Europe/Berlin',
 404             'Central Europe Standard Time' => 'Europe/Budapest',
 405             'Romance Standard Time' => 'Europe/Paris',
 406             'Central European Standard Time' => 'Europe/Warsaw',
 407             'W. Central Africa Standard Time' => 'Africa/Lagos',
 408             'Namibia Standard Time' => 'Africa/Windhoek',
 409             'Jordan Standard Time' => 'Asia/Amman',
 410             'GTB Standard Time' => 'Europe/Bucharest',
 411             'Middle East Standard Time' => 'Asia/Beirut',
 412             'Egypt Standard Time' => 'Africa/Cairo',
 413             'Syria Standard Time' => 'Asia/Damascus',
 414             'South Africa Standard Time' => 'Africa/Johannesburg',
 415             'FLE Standard Time' => 'Europe/Kiev',
 416             'Turkey Standard Time' => 'Europe/Istanbul',
 417             'Israel Standard Time' => 'Asia/Jerusalem',
 418             'Kaliningrad Standard Time' => 'Europe/Kaliningrad',
 419             'Libya Standard Time' => 'Africa/Tripoli',
 420             'Arabic Standard Time' => 'Asia/Baghdad',
 421             'Arab Standard Time' => 'Asia/Riyadh',
 422             'Belarus Standard Time' => 'Europe/Minsk',
 423             'Russian Standard Time' => 'Europe/Moscow',
 424             'E. Africa Standard Time' => 'Africa/Nairobi',
 425             'Iran Standard Time' => 'Asia/Tehran',
 426             'Arabian Standard Time' => 'Asia/Dubai',
 427             'Azerbaijan Standard Time' => 'Asia/Baku',
 428             'Russia Time Zone 3' => 'Europe/Samara',
 429             'Mauritius Standard Time' => 'Indian/Mauritius',
 430             'Georgian Standard Time' => 'Asia/Tbilisi',
 431             'Caucasus Standard Time' => 'Asia/Yerevan',
 432             'Afghanistan Standard Time' => 'Asia/Kabul',
 433             'West Asia Standard Time' => 'Asia/Tashkent',
 434             'Ekaterinburg Standard Time' => 'Asia/Yekaterinburg',
 435             'Pakistan Standard Time' => 'Asia/Karachi',
 436             'India Standard Time' => 'Asia/Kolkata', // PHP and Windows differ in spelling.
 437             'Sri Lanka Standard Time' => 'Asia/Colombo',
 438             'Nepal Standard Time' => 'Asia/Kathmandu',
 439             'Central Asia Standard Time' => 'Asia/Almaty',
 440             'Bangladesh Standard Time' => 'Asia/Dhaka',
 441             'N. Central Asia Standard Time' => 'Asia/Novosibirsk',
 442             'Myanmar Standard Time' => 'Asia/Yangon',
 443             'SE Asia Standard Time' => 'Asia/Bangkok',
 444             'S.E. Asia Standard Time' => 'Asia/Bangkok',
 445             'North Asia Standard Time' => 'Asia/Krasnoyarsk',
 446             'China Standard Time' => 'Asia/Shanghai',
 447             'North Asia East Standard Time' => 'Asia/Irkutsk',
 448             'Singapore Standard Time' => 'Asia/Singapore',
 449             'W. Australia Standard Time' => 'Australia/Perth',
 450             'Taipei Standard Time' => 'Asia/Taipei',
 451             'Ulaanbaatar Standard Time' => 'Asia/Ulaanbaatar',
 452             'Tokyo Standard Time' => 'Asia/Tokyo',
 453             'Korea Standard Time' => 'Asia/Seoul',
 454             'Yakutsk Standard Time' => 'Asia/Yakutsk',
 455             'Cen. Australia Standard Time' => 'Australia/Adelaide',
 456             'AUS Central Standard Time' => 'Australia/Darwin',
 457             'A.U.S. Central Standard Time' => 'Australia/Darwin',
 458             'E. Australia Standard Time' => 'Australia/Brisbane',
 459             'AUS Eastern Standard Time' => 'Australia/Sydney',
 460             'A.U.S. Eastern Standard Time' => 'Australia/Sydney',
 461             'West Pacific Standard Time' => 'Pacific/Port_Moresby',
 462             'Tasmania Standard Time' => 'Australia/Hobart',
 463             'Magadan Standard Time' => 'Asia/Magadan',
 464             'Vladivostok Standard Time' => 'Asia/Vladivostok',
 465             'Russia Time Zone 10' => 'Asia/Srednekolymsk',
 466             'Central Pacific Standard Time' => 'Pacific/Guadalcanal',
 467             'Russia Time Zone 11' => 'Asia/Kamchatka',
 468             'New Zealand Standard Time' => 'Pacific/Auckland',
 469             'Fiji Standard Time' => 'Pacific/Fiji',
 470             'Fiji Islands Standard Time' => 'Pacific/Fiji',
 471             'Tonga Standard Time' => 'Pacific/Tongatapu',
 472             'Samoa Standard Time' => 'Pacific/Apia',
 473             'Line Islands Standard Time' => 'Pacific/Kiritimati',
 474             'Mexico Standard Time 2' => 'America/Chihuahua',
 475             'Mexico Standard Time' => 'America/Mexico_City',
 476             'U.S. Mountain Standard Time' => 'America/Phoenix',
 477             'Mid-Atlantic Standard Time' => 'Atlantic/South_Georgia',
 478             'E. Europe Standard Time' => 'Europe/Minsk',
 479             'Transitional Islamic State of Afghanistan Standard Time' => 'Asia/Kabul',
 480             'Armenian Standard Time' => 'Asia/Yerevan',
 481             'Kamchatka Standard Time' => 'Asia/Kamchatka',
 482
 483             // A lot more bad legacy (deprecated) time zones.
 484             'Australia/ACT' => 'Australia/Sydney',
 485             'Australia/LHI' => 'Australia/Lord_Howe',
 486             'Australia/North' => 'Australia/Darwin',
 487             'Australia/NSW' => 'Australia/Sydney',
 488             'Australia/Queensland' => 'Australia/Brisbane',
 489             'Australia/South' => 'Australia/Adelaide',
 490             'Australia/Tasmania' => 'Australia/Hobart',
 491             'Australia/Victoria' => 'Australia/Melbourne',
 492             'Australia/West' => 'Australia/Perth',
 493             'Brazil/Acre' => 'America/Rio_Branco',
 494             'Brazil/DeNoronha' => 'America/Noronha',
 495             'Brazil/East' => 'America/Sao_Paulo',
 496             'Brazil/West' => 'America/Manaus',
 497             'Canada/Atlantic' => 'America/Halifax',
 498             'Canada/Central' => 'America/Winnipeg',
 499             'Canada/Eastern' => 'America/Toronto',
 500             'Canada/Mountain' => 'America/Edmonton',
 501             'Canada/Newfoundland' => 'America/St_Johns',
 502             'Canada/Pacific' => 'America/Vancouver',
 503             'Canada/Saskatchewan' => 'America/Regina',
 504             'Canada/Yukon' => 'America/Whitehorse',
 505             'CDT' => 'America/Chicago',
 506             'CET' => 'Europe/Berlin',
 507             'Central European Time' => 'Europe/Berlin',
 508             'Central Time' => 'America/Chicago',
 509             'Chile/Continental' => 'America/Santiago',
 510             'Chile/EasterIsland' => 'Pacific/Easter',
 511             'China Time' => 'Asia/Shanghai',
 512             'CST' => 'America/Chicago',
 513             'CST6CDT' => 'America/Chicago',
 514             'Cuba' => 'America/Havana',
 515             'EDT' => 'America/New_York',
 516             'EET' => 'Europe/Kiev',
 517             'Egypt' => 'Africa/Cairo',
 518             'Eire' => 'Europe/Dublin',
 519             'EST' => 'America/Cancun',
 520             'EST5EDT' => 'America/New_York',
 521             'Eastern Time' => 'America/New_York',
 522             'Etc/Greenwich' => 'Etc/GMT',
 523             'Etc/UCT' => 'Etc/UTC',
 524             'Etc/Universal' => 'Etc/UTC',
 525             'Etc/Zulu' => 'Etc/UTC',
 526             'FET' => 'Europe/Minsk',
 527             'GB' => 'Europe/London',
 528             'GB-Eire' => 'Europe/London',
 529             'Greenwich' => 'Etc/GMT',
 530             'Hongkong' => 'Asia/Hong_Kong',
 531             'HST' => 'Pacific/Honolulu',
 532             'Iceland' => 'Atlantic/Reykjavik',
 533             'India Time' => 'Asia/Kolkata',
 534             'Iran' => 'Asia/Tehran',
 535             'Israel' => 'Asia/Jerusalem',
 536             'IST' => 'Asia/Kolkata',
 537             'Jamaica' => 'America/Jamaica',
 538             'Japan' => 'Asia/Tokyo',
 539             'Japan Standard Time' => 'Asia/Tokyo',
 540             'Japan Time' => 'Asia/Tokyo',
 541             'JST' => 'Asia/Tokyo',
 542             'Kwajalein' => 'Pacific/Kwajalein',
 543             'Libya' => 'Africa/Tripoli',
 544             'MDT' => 'America/Denver',
 545             'MET' => 'Europe/Paris',
 546             'Mexico/BajaNorte' => 'America/Tijuana',
 547             'Mexico/BajaSur' => 'America/Mazatlan',
 548             'Mexico/General' => 'America/Mexico_City',
 549             'MST' => 'America/Phoenix',
 550             'MST7MDT' => 'America/Denver',
 551             'Navajo' => 'America/Denver',
 552             'NZ' => 'Pacific/Auckland',
 553             'NZ-CHAT' => 'Pacific/Chatham',
 554             'Pacific Time' => 'America/Los_Angeles',
 555             'PDT' => 'America/Los_Angeles',
 556             'Poland' => 'Europe/Warsaw',
 557             'Portugal' => 'Europe/Lisbon',
 558             'PRC' => 'Asia/Shanghai',
 559             'PST' => 'America/Los_Angeles',
 560             'PST8PDT' => 'America/Los_Angeles',
 561             'ROC' => 'Asia/Taipei',
 562             'ROK' => 'Asia/Seoul',
 563             'Singapore' => 'Asia/Singapore',
 564             'Turkey' => 'Europe/Istanbul',
 565             'UCT' => 'Etc/UTC',
 566             'Universal' => 'Etc/UTC',
 567             'US/Alaska' => 'America/Anchorage',
 568             'US/Aleutian' => 'America/Adak',
 569             'US/Arizona' => 'America/Phoenix',
 570             'US/Central' => 'America/Chicago',
 571             'US/East-Indiana' => 'America/Indiana/Indianapolis',
 572             'US/Eastern' => 'America/New_York',
 573             'US/Hawaii' => 'Pacific/Honolulu',
 574             'US/Indiana-Starke' => 'America/Indiana/Knox',
 575             'US/Michigan' => 'America/Detroit',
 576             'US/Mountain' => 'America/Denver',
 577             'US/Pacific' => 'America/Los_Angeles',
 578             'US/Pacific-New' => 'America/Los_Angeles',
 579             'US/Samoa' => 'Pacific/Pago_Pago',
 580             'W-SU' => 'Europe/Moscow',
 581             'WET' => 'Europe/London',
 582             'Zulu' => 'Etc/UTC',
 583
 584             // Some UTC variations.
 585             'UTC-01' => 'Etc/GMT+1',
 586             'UTC-02' => 'Etc/GMT+2',
 587             'UTC-03' => 'Etc/GMT+3',
 588             'UTC-04' => 'Etc/GMT+4',
 589             'UTC-05' => 'Etc/GMT+5',
 590             'UTC-06' => 'Etc/GMT+6',
 591             'UTC-07' => 'Etc/GMT+7',
 592             'UTC-08' => 'Etc/GMT+8',
 593             'UTC-09' => 'Etc/GMT+9',
 594
 595             // Some weird GMTs.
 596             'Etc/GMT+0' => 'Etc/GMT',
 597             'Etc/GMT-0' => 'Etc/GMT',
 598             'Etc/GMT0' => 'Etc/GMT',
 599
 600             // Link old timezone names with their new names.
 601             'Africa/Asmera' => 'Africa/Asmara',
 602             'Africa/Timbuktu' => 'Africa/Abidjan',
 603             'America/Argentina/ComodRivadavia' => 'America/Argentina/Catamarca',
 604             'America/Atka' => 'America/Adak',
 605             'America/Buenos_Aires' => 'America/Argentina/Buenos_Aires',
 606             'America/Catamarca' => 'America/Argentina/Catamarca',
 607             'America/Coral_Harbour' => 'America/Atikokan',
 608             'America/Cordoba' => 'America/Argentina/Cordoba',
 609             'America/Ensenada' => 'America/Tijuana',
 610             'America/Fort_Wayne' => 'America/Indiana/Indianapolis',
 611             'America/Indianapolis' => 'America/Indiana/Indianapolis',
 612             'America/Jujuy' => 'America/Argentina/Jujuy',
 613             'America/Knox_IN' => 'America/Indiana/Knox',
 614             'America/Louisville' => 'America/Kentucky/Louisville',
 615             'America/Mendoza' => 'America/Argentina/Mendoza',
 616             'America/Montreal' => 'America/Toronto',
 617             'America/Porto_Acre' => 'America/Rio_Branco',
 618             'America/Rosario' => 'America/Argentina/Cordoba',
 619             'America/Santa_Isabel' => 'America/Tijuana',
 620             'America/Shiprock' => 'America/Denver',
 621             'America/Virgin' => 'America/Port_of_Spain',
 622             'Antarctica/South_Pole' => 'Pacific/Auckland',
 623             'Asia/Ashkhabad' => 'Asia/Ashgabat',
 624             'Asia/Calcutta' => 'Asia/Kolkata',
 625             'Asia/Chongqing' => 'Asia/Shanghai',
 626             'Asia/Chungking' => 'Asia/Shanghai',
 627             'Asia/Dacca' => 'Asia/Dhaka',
 628             'Asia/Harbin' => 'Asia/Shanghai',
 629             'Asia/Istanbul' => 'Europe/Istanbul',
 630             'Asia/Kashgar' => 'Asia/Urumqi',
 631             'Asia/Katmandu' => 'Asia/Kathmandu',
 632             'Asia/Macao' => 'Asia/Macau',
 633             'Asia/Rangoon' => 'Asia/Yangon',
 634             'Asia/Saigon' => 'Asia/Ho_Chi_Minh',
 635             'Asia/Tel_Aviv' => 'Asia/Jerusalem',
 636             'Asia/Thimbu' => 'Asia/Thimphu',
 637             'Asia/Ujung_Pandang' => 'Asia/Makassar',
 638             'Asia/Ulan_Bator' => 'Asia/Ulaanbaatar',
 639             'Atlantic/Faeroe' => 'Atlantic/Faroe',
 640             'Atlantic/Jan_Mayen' => 'Europe/Oslo',
 641             'Australia/Canberra' => 'Australia/Sydney',
 642             'Australia/Yancowinna' => 'Australia/Broken_Hill',
 643             'Europe/Belfast' => 'Europe/London',
 644             'Europe/Nicosia' => 'Asia/Nicosia',
 645             'Europe/Tiraspol' => 'Europe/Chisinau',
 646             'Pacific/Johnston' => 'Pacific/Honolulu',
 647             'Pacific/Ponape' => 'Pacific/Pohnpei',
 648             'Pacific/Samoa' => 'Pacific/Pago_Pago',
 649             'Pacific/Truk' => 'Pacific/Chuuk',
 650             'Pacific/Yap' => 'Pacific/Chuuk',
 651         );
 652
 653         // Legacy GMT fallback.
 654         for ($i = -12; $i <= 14; $i++) {
 655             $off = abs($i);
 656             if ($i < 0) {
 657                 $mapto = 'Etc/GMT+' . $off;
 658                 $utc = 'UTC-' . $off;
 659                 $gmt = 'GMT-' . $off;
 660             } else if ($i > 0) {
 661                 $mapto = 'Etc/GMT-' . $off;
 662                 $utc = 'UTC+' . $off;
 663                 $gmt = 'GMT+' . $off;
 664             } else {
 665                 $mapto = 'Etc/GMT';
 666                 $utc = 'UTC';
 667                 $gmt = 'GMT';
 668             }
 669             if (isset(self::$bczones[$mapto])) {
 670                 self::$badzones[$i . ''] = $mapto;
 671                 self::$badzones[$i . '.0'] = $mapto;
 672                 self::$badzones[$utc] = $mapto;
 673                 self::$badzones[$gmt] = $mapto;
 674             }
 675         }
 676
 677         // Legacy Moodle half an hour offsets - pick any city nearby, ideally without DST.
 678         self::$badzones['4.5'] = 'Asia/Kabul';
 679         self::$badzones['5.5'] = 'Asia/Kolkata';
 680         self::$badzones['6.5'] = 'Asia/Rangoon';
 681         self::$badzones['9.5'] = 'Australia/Darwin';
 682
 683         // Remove bad zones that are elsewhere.
 684         foreach (self::$bczones as $zone => $unused) {
 685             if (isset(self::$badzones[$zone])) {
 686                 unset(self::$badzones[$zone]);
 687             }
 688         }
 689         foreach (self::$goodzones as $zone => $unused) {
 690             if (isset(self::$badzones[$zone])) {
 691                 unset(self::$badzones[$zone]);
 692             }
 693         }
 694     }
 695 }