Date Helper
***********

The Date Helper file contains functions that help you work with dates.

* Loading this Helper

* Available Functions

* Timezone Reference


Loading this Helper
===================

This helper is loaded using the following code:

   $this->load->helper('date');


Available Functions
===================

The following functions are available:

now([$timezone = NULL])

   Parameters:
      * **$timezone** ("string") – Timezone

   Returns:
      UNIX timestamp

   Return type:
      "int"

   Returns the current time as a UNIX timestamp, referenced either to
   your server’s local time or any PHP supported timezone, based on
   the “time reference” setting in your config file. If you do not
   intend to set your master time reference to any other PHP supported
   timezone (which you’ll typically do if you run a site that lets
   each user set their own timezone settings) there is no benefit to
   using this function over PHP’s "time()" function.

      echo now('Australia/Victoria');

   If a timezone is not provided, it will return "time()" based on the
   **time_reference** setting.

mdate([$datestr = ''[, $time = '']])

   Parameters:
      * **$datestr** ("string") – Date string

      * **$time** ("int") – UNIX timestamp

   Returns:
      MySQL-formatted date

   Return type:
      "string"

   This function is identical to PHP’s date() function, except that it
   lets you use MySQL style date codes, where each code letter is
   preceded with a percent sign, e.g. *%Y %m %d*

   The benefit of doing dates this way is that you don’t have to worry
   about escaping any characters that are not date codes, as you would
   normally have to do with the "date()" function.

   Example:

      $datestring = 'Year: %Y Month: %m Day: %d - %h:%i %a';
      $time = time();
      echo mdate($datestring, $time);

   If a timestamp is not included in the second parameter the current
   time will be used.

standard_date([$fmt = 'DATE_RFC822'[, $time = NULL]])

   Parameters:
      * **$fmt** ("string") – Date format

      * **$time** ("int") – UNIX timestamp

   Returns:
      Formatted date or FALSE on invalid format

   Return type:
      "string"

   Lets you generate a date string in one of several standardized
   formats.

   Example:

      $format = 'DATE_RFC822';
      $time = time();
      echo standard_date($format, $time);

   Note:

     This function is DEPRECATED. Use the native "date()" combined
     with DateTime’s format constants instead:

        echo date(DATE_RFC822, time());

   **Supported formats:**

   +-----------------+-------------------------+----------------------------------------+
   | Constant        | Description             | Example                                |
   |=================|=========================|========================================|
   | DATE_ATOM       | Atom                    | 2005-08-15T16:13:03+0000               |
   +-----------------+-------------------------+----------------------------------------+
   | DATE_COOKIE     | HTTP Cookies            | Sun, 14 Aug 2005 16:13:03 UTC          |
   +-----------------+-------------------------+----------------------------------------+
   | DATE_ISO8601    | ISO-8601                | 2005-08-14T16:13:03+00:00              |
   +-----------------+-------------------------+----------------------------------------+
   | DATE_RFC822     | RFC 822                 | Sun, 14 Aug 05 16:13:03 UTC            |
   +-----------------+-------------------------+----------------------------------------+
   | DATE_RFC850     | RFC 850                 | Sunday, 14-Aug-05 16:13:03 UTC         |
   +-----------------+-------------------------+----------------------------------------+
   | DATE_RFC1036    | RFC 1036                | Sunday, 14-Aug-05 16:13:03 UTC         |
   +-----------------+-------------------------+----------------------------------------+
   | DATE_RFC1123    | RFC 1123                | Sun, 14 Aug 2005 16:13:03 UTC          |
   +-----------------+-------------------------+----------------------------------------+
   | DATE_RFC2822    | RFC 2822                | Sun, 14 Aug 2005 16:13:03 +0000        |
   +-----------------+-------------------------+----------------------------------------+
   | DATE_RSS        | RSS                     | Sun, 14 Aug 2005 16:13:03 UTC          |
   +-----------------+-------------------------+----------------------------------------+
   | DATE_W3C        | W3C                     | 2005-08-14T16:13:03+0000               |
   +-----------------+-------------------------+----------------------------------------+

local_to_gmt([$time = ''])

   Parameters:
      * **$time** ("int") – UNIX timestamp

   Returns:
      UNIX timestamp

   Return type:
      "int"

   Takes a UNIX timestamp as input and returns it as GMT.

   Example:

      $gmt = local_to_gmt(time());

gmt_to_local([$time = ''[, $timezone = 'UTC'[, $dst = FALSE]]])

   Parameters:
      * **$time** ("int") – UNIX timestamp

      * **$timezone** ("string") – Timezone

      * **$dst** ("bool") – Whether DST is active

   Returns:
      UNIX timestamp

   Return type:
      "int"

   Takes a UNIX timestamp (referenced to GMT) as input, and converts
   it to a localized timestamp based on the timezone and Daylight
   Saving Time submitted.

   Example:

      $timestamp = 1140153693;
      $timezone  = 'UM8';
      $daylight_saving = TRUE;
      echo gmt_to_local($timestamp, $timezone, $daylight_saving);

   Note:

     For a list of timezones see the reference at the bottom of this
     page.

mysql_to_unix([$time = ''])

   Parameters:
      * **$time** ("string") – MySQL timestamp

   Returns:
      UNIX timestamp

   Return type:
      "int"

   Takes a MySQL Timestamp as input and returns it as a UNIX
   timestamp.

   Example:

      $unix = mysql_to_unix('20061124092345');

unix_to_human([$time = ''[, $seconds = FALSE[, $fmt = 'us']]])

   Parameters:
      * **$time** ("int") – UNIX timestamp

      * **$seconds** ("bool") – Whether to show seconds

      * **$fmt** ("string") – format (us or euro)

   Returns:
      Formatted date

   Return type:
      "string"

   Takes a UNIX timestamp as input and returns it in a human readable
   format with this prototype:

      YYYY-MM-DD HH:MM:SS AM/PM

   This can be useful if you need to display a date in a form field
   for submission.

   The time can be formatted with or without seconds, and it can be
   set to European or US format. If only the timestamp is submitted it
   will return the time without seconds formatted for the U.S.

   Examples:

      $now = time();
      echo unix_to_human($now); // U.S. time, no seconds
      echo unix_to_human($now, TRUE, 'us'); // U.S. time with seconds
      echo unix_to_human($now, TRUE, 'eu'); // Euro time with seconds

human_to_unix([$datestr = ''])

   Parameters:
      * **$datestr** ("int") – Date string

   Returns:
      UNIX timestamp or FALSE on failure

   Return type:
      "int"

   The opposite of the "unix_to_time()" function. Takes a “human” time
   as input and returns it as a UNIX timestamp. This is useful if you
   accept “human” formatted dates submitted via a form. Returns
   boolean FALSE date string passed to it is not formatted as
   indicated above.

   Example:

      $now = time();
      $human = unix_to_human($now);
      $unix = human_to_unix($human);

nice_date([$bad_date = ''[, $format = FALSE]])

   Parameters:
      * **$bad_date** ("int") – The terribly formatted date-like
        string

      * **$format** ("string") – Date format to return (same as PHP’s
        "date()" function)

   Returns:
      Formatted date

   Return type:
      "string"

   This function can take a number poorly-formed date formats and
   convert them into something useful. It also accepts well-formed
   dates.

   The function will return a UNIX timestamp by default. You can,
   optionally, pass a format string (the same type as the PHP "date()"
   function accepts) as the second parameter.

   Example:

      $bad_date = '199605';
      // Should Produce: 1996-05-01
      $better_date = nice_date($bad_date, 'Y-m-d');

      $bad_date = '9-11-2001';
      // Should Produce: 2001-09-11
      $better_date = nice_date($bad_date, 'Y-m-d');

   Note:

     This function is DEPRECATED. Use PHP’s native DateTime class
     instead.

timespan([$seconds = 1[, $time = ''[, $units = '']]])

   Parameters:
      * **$seconds** ("int") – Number of seconds

      * **$time** ("string") – UNIX timestamp

      * **$units** ("int") – Number of time units to display

   Returns:
      Formatted time difference

   Return type:
      "string"

   Formats a UNIX timestamp so that is appears similar to this:

      1 Year, 10 Months, 2 Weeks, 5 Days, 10 Hours, 16 Minutes

   The first parameter must contain a UNIX timestamp. The second
   parameter must contain a timestamp that is greater that the first
   timestamp. The thirdparameter is optional and limits the number of
   time units to display.

   If the second parameter empty, the current time will be used.

   The most common purpose for this function is to show how much time
   has elapsed from some point in time in the past to now.

   Example:

      $post_date = '1079621429';
      $now = time();
      $units = 2;
      echo timespan($post_date, $now, $units);

   Note:

     The text generated by this function is found in the following
     language file: *language/<your_lang>/date_lang.php*

days_in_month([$month = 0[, $year = '']])

   Parameters:
      * **$month** ("int") – a numeric month

      * **$year** ("int") – a numeric year

   Returns:
      Count of days in the specified month

   Return type:
      "int"

   Returns the number of days in a given month/year. Takes leap years
   into account.

   Example:

      echo days_in_month(06, 2005);

   If the second parameter is empty, the current year will be used.

   Note:

     This function will alias the native "cal_days_in_month()", if it
     is available.

date_range([$unix_start = ''[, $mixed = ''[, $is_unix = TRUE[, $format = 'Y-m-d']]]])

   Parameters:
      * **$unix_start** ("int") – UNIX timestamp of the range start
        date

      * **$mixed** ("int") – UNIX timestamp of the range end date or
        interval in days

      * **$is_unix** ("bool") – set to FALSE if $mixed is not a
        timestamp

      * **$format** ("string") – Output date format, same as in
        "date()"

   Returns:
      An array of dates

   Return type:
      "array"

   Returns a list of dates within a specified period.

   Example:

      $range = date_range('2012-01-01', '2012-01-15');
      echo "First 15 days of 2012:";
      foreach ($range as $date)
      {
              echo $date."\n";
      }

timezones([$tz = ''])

   Parameters:
      * **$tz** ("string") – A numeric timezone

   Returns:
      Hour difference from UTC

   Return type:
      "int"

   Takes a timezone reference (for a list of valid timezones, see the
   “Timezone Reference” below) and returns the number of hours offset
   from UTC.

   Example:

      echo timezones('UM5');

   This function is useful when used with "timezone_menu()".

timezone_menu([$default = 'UTC'[, $class = ''[, $name = 'timezones'[, $attributes = '']]]])

   Parameters:
      * **$default** ("string") – Timezone

      * **$class** ("string") – Class name

      * **$name** ("string") – Menu name

      * **$attributes** ("mixed") – HTML attributes

   Returns:
      HTML drop down menu with time zones

   Return type:
      "string"

   Generates a pull-down menu of timezones, like this one:

   This menu is useful if you run a membership site in which your
   users are allowed to set their local timezone value.

   The first parameter lets you set the “selected” state of the menu.
   For example, to set Pacific time as the default you will do this:

      echo timezone_menu('UM8');

   Please see the timezone reference below to see the values of this
   menu.

   The second parameter lets you set a CSS class name for the menu.

   The fourth parameter lets you set one or more attributes on the
   generated select tag.

   Note:

     The text contained in the menu is found in the following language
     file: *language/<your_lang>/date_lang.php*


Timezone Reference
==================

The following table indicates each timezone and its location.

Note some of the location lists have been abridged for clarity and
formatting.

+-------------+-----------------------------------------------------------------------+
| Time Zone   | Location                                                              |
|=============|=======================================================================|
| UM12        | (UTC - 12:00) Baker/Howland Island                                    |
+-------------+-----------------------------------------------------------------------+
| UM11        | (UTC - 11:00) Samoa Time Zone, Niue                                   |
+-------------+-----------------------------------------------------------------------+
| UM10        | (UTC - 10:00) Hawaii-Aleutian Standard Time, Cook Islands             |
+-------------+-----------------------------------------------------------------------+
| UM95        | (UTC - 09:30) Marquesas Islands                                       |
+-------------+-----------------------------------------------------------------------+
| UM9         | (UTC - 09:00) Alaska Standard Time, Gambier Islands                   |
+-------------+-----------------------------------------------------------------------+
| UM8         | (UTC - 08:00) Pacific Standard Time, Clipperton Island                |
+-------------+-----------------------------------------------------------------------+
| UM7         | (UTC - 07:00) Mountain Standard Time                                  |
+-------------+-----------------------------------------------------------------------+
| UM6         | (UTC - 06:00) Central Standard Time                                   |
+-------------+-----------------------------------------------------------------------+
| UM5         | (UTC - 05:00) Eastern Standard Time, Western Caribbean                |
+-------------+-----------------------------------------------------------------------+
| UM45        | (UTC - 04:30) Venezuelan Standard Time                                |
+-------------+-----------------------------------------------------------------------+
| UM4         | (UTC - 04:00) Atlantic Standard Time, Eastern Caribbean               |
+-------------+-----------------------------------------------------------------------+
| UM35        | (UTC - 03:30) Newfoundland Standard Time                              |
+-------------+-----------------------------------------------------------------------+
| UM3         | (UTC - 03:00) Argentina, Brazil, French Guiana, Uruguay               |
+-------------+-----------------------------------------------------------------------+
| UM2         | (UTC - 02:00) South Georgia/South Sandwich Islands                    |
+-------------+-----------------------------------------------------------------------+
| UM1         | (UTC -1:00) Azores, Cape Verde Islands                                |
+-------------+-----------------------------------------------------------------------+
| UTC         | (UTC) Greenwich Mean Time, Western European Time                      |
+-------------+-----------------------------------------------------------------------+
| UP1         | (UTC +1:00) Central European Time, West Africa Time                   |
+-------------+-----------------------------------------------------------------------+
| UP2         | (UTC +2:00) Central Africa Time, Eastern European Time                |
+-------------+-----------------------------------------------------------------------+
| UP3         | (UTC +3:00) Moscow Time, East Africa Time                             |
+-------------+-----------------------------------------------------------------------+
| UP35        | (UTC +3:30) Iran Standard Time                                        |
+-------------+-----------------------------------------------------------------------+
| UP4         | (UTC +4:00) Azerbaijan Standard Time, Samara Time                     |
+-------------+-----------------------------------------------------------------------+
| UP45        | (UTC +4:30) Afghanistan                                               |
+-------------+-----------------------------------------------------------------------+
| UP5         | (UTC +5:00) Pakistan Standard Time, Yekaterinburg Time                |
+-------------+-----------------------------------------------------------------------+
| UP55        | (UTC +5:30) Indian Standard Time, Sri Lanka Time                      |
+-------------+-----------------------------------------------------------------------+
| UP575       | (UTC +5:45) Nepal Time                                                |
+-------------+-----------------------------------------------------------------------+
| UP6         | (UTC +6:00) Bangladesh Standard Time, Bhutan Time, Omsk Time          |
+-------------+-----------------------------------------------------------------------+
| UP65        | (UTC +6:30) Cocos Islands, Myanmar                                    |
+-------------+-----------------------------------------------------------------------+
| UP7         | (UTC +7:00) Krasnoyarsk Time, Cambodia, Laos, Thailand, Vietnam       |
+-------------+-----------------------------------------------------------------------+
| UP8         | (UTC +8:00) Australian Western Standard Time, Beijing Time            |
+-------------+-----------------------------------------------------------------------+
| UP875       | (UTC +8:45) Australian Central Western Standard Time                  |
+-------------+-----------------------------------------------------------------------+
| UP9         | (UTC +9:00) Japan Standard Time, Korea Standard Time, Yakutsk         |
+-------------+-----------------------------------------------------------------------+
| UP95        | (UTC +9:30) Australian Central Standard Time                          |
+-------------+-----------------------------------------------------------------------+
| UP10        | (UTC +10:00) Australian Eastern Standard Time, Vladivostok Time       |
+-------------+-----------------------------------------------------------------------+
| UP105       | (UTC +10:30) Lord Howe Island                                         |
+-------------+-----------------------------------------------------------------------+
| UP11        | (UTC +11:00) Srednekolymsk Time, Solomon Islands, Vanuatu             |
+-------------+-----------------------------------------------------------------------+
| UP115       | (UTC +11:30) Norfolk Island                                           |
+-------------+-----------------------------------------------------------------------+
| UP12        | (UTC +12:00) Fiji, Gilbert Islands, Kamchatka, New Zealand            |
+-------------+-----------------------------------------------------------------------+
| UP1275      | (UTC +12:45) Chatham Islands Standard Time                            |
+-------------+-----------------------------------------------------------------------+
| UP13        | (UTC +13:00) Phoenix Islands Time, Tonga                              |
+-------------+-----------------------------------------------------------------------+
| UP14        | (UTC +14:00) Line Islands                                             |
+-------------+-----------------------------------------------------------------------+
