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andyfoster/CronSchedule.php

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Revisions

  1. @m4tthumphrey m4tthumphrey revised this gist Jan 3, 2014. 1 changed file with 5 additions and 3 deletions.
    8 changes: 5 additions & 3 deletions README.md
    View file
    Original file line number Diff line number Diff line change
    @@ -12,8 +12,10 @@ All copyright should belong to Joost Brugman, 2012.
    Usage
    -----

    $schedule = CronSchedule::fromCronString('30 01 01 * *');
    ```php
    $schedule = CronSchedule::fromCronString('30 01 01 * *');

    echo $schedule->asNaturalLanguage();
    echo $schedule->asNaturalLanguage();

    // At 01:30 on the 1st of every month.
    // At 01:30 on the 1st of every month.
    ```
  2. @m4tthumphrey m4tthumphrey revised this gist Jan 3, 2014. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion README.md
    View file
    Original file line number Diff line number Diff line change
    @@ -1,7 +1,7 @@
    CronSchedule
    ============

    Allows one to parse a cron expression into human readable text (as well as other things but I suggest using @mtdowling's [cron-expression](https://github.com/mtdowling/cron-expression) for those).
    Allows one to parse a cron expression into human readable text (as well as other things but I suggest using [@mtdowling](https://github.com/mtdowling)'s [cron-expression](https://github.com/mtdowling/cron-expression) for those).

    Only supports English for now.

  3. @m4tthumphrey m4tthumphrey revised this gist Jan 3, 2014. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion README.md
    View file
    Original file line number Diff line number Diff line change
    @@ -1,7 +1,7 @@
    CronSchedule
    ============

    Allows one to parse a cron expression into human readable text (as well as other things but I suggest using mtdowling's cron-expression for those).
    Allows one to parse a cron expression into human readable text (as well as other things but I suggest using @mtdowling's [cron-expression](https://github.com/mtdowling/cron-expression) for those).

    Only supports English for now.

  4. @m4tthumphrey m4tthumphrey revised this gist Jan 3, 2014. 1 changed file with 11 additions and 2 deletions.
    13 changes: 11 additions & 2 deletions README.md
    View file
    Original file line number Diff line number Diff line change
    @@ -1,10 +1,19 @@
    CronSchedule
    ============

    Allows one to parse a cron expression into human readable text.
    Allows one to parse a cron expression into human readable text (as well as other things but I suggest using mtdowling's cron-expression for those).

    Only supports English for now.

    It is a (very slightly) modified version of the script used [here](http://www.joostbrugman.com/bitsofthought/page/4/Converting_Crontab_Entries_To_Plain_English_%28Or_Any_Other_Language%29).

    All copyright should belong to Joost Brugman, 2012.
    All copyright should belong to Joost Brugman, 2012.

    Usage
    -----

    $schedule = CronSchedule::fromCronString('30 01 01 * *');

    echo $schedule->asNaturalLanguage();

    // At 01:30 on the 1st of every month.
  5. @m4tthumphrey m4tthumphrey revised this gist Jan 3, 2014. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion README.md
    View file
    Original file line number Diff line number Diff line change
    @@ -7,4 +7,4 @@ Only supports English for now.

    It is a (very slightly) modified version of the script used [here](http://www.joostbrugman.com/bitsofthought/page/4/Converting_Crontab_Entries_To_Plain_English_%28Or_Any_Other_Language%29).

    All copyright should be long to Joost Brugman, 2012.
    All copyright should belong to Joost Brugman, 2012.
  6. @m4tthumphrey m4tthumphrey revised this gist Jan 3, 2014. 1 changed file with 3 additions and 1 deletion.
    4 changes: 3 additions & 1 deletion README.md
    View file
    Original file line number Diff line number Diff line change
    @@ -5,4 +5,6 @@ Allows one to parse a cron expression into human readable text.

    Only supports English for now.

    It is a (very slightly) modified version of the script used [here](http://www.joostbrugman.com/bitsofthought/page/4/Converting_Crontab_Entries_To_Plain_English_%28Or_Any_Other_Language%29. All copyright should be long to Joost Brugman).
    It is a (very slightly) modified version of the script used [here](http://www.joostbrugman.com/bitsofthought/page/4/Converting_Crontab_Entries_To_Plain_English_%28Or_Any_Other_Language%29).

    All copyright should be long to Joost Brugman, 2012.
  7. @m4tthumphrey m4tthumphrey revised this gist Jan 3, 2014. 1 changed file with 8 additions and 0 deletions.
    8 changes: 8 additions & 0 deletions README.md
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,8 @@
    CronSchedule
    ============

    Allows one to parse a cron expression into human readable text.

    Only supports English for now.

    It is a (very slightly) modified version of the script used [here](http://www.joostbrugman.com/bitsofthought/page/4/Converting_Crontab_Entries_To_Plain_English_%28Or_Any_Other_Language%29. All copyright should be long to Joost Brugman).
  8. @m4tthumphrey m4tthumphrey created this gist Jan 3, 2014.
    1,362 changes: 1,362 additions & 0 deletions CronSchedule.php
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    Original file line number Diff line number Diff line change
    @@ -0,0 +1,1362 @@
    <?php
    /*
    * Plugin: StreamlineFoundation
    *
    * Class: Schedule
    *
    * Description: Provides scheduling mechanics including creating a schedule, testing if a specific moment is part of the schedule, moving back
    * and forth between scheduled moments in time and translating the created schedule back to a human readable form.
    *
    * Usage: ::fromCronString() creates a new Schedule class and requires a string in the cron ('* * * * *', $language) format.
    *
    * ->next(<datetime>) returns the first scheduled datetime after <datetime> in array format.
    * ->nextAsString(<datetime>) does the same with an ISO string as the result.
    * ->nextAsTime(<datetime>) does the same with a UNIX timestamp as the result.
    *
    * ->previous(<datetime>) returns the first scheduled datetime before <datetime> in array format.
    * ->previousAsString(<datetime>) does the same with an ISO string as the result.
    * ->previousAsTime(<datetime>) does the same with a UNIX timestamp as the result.
    *
    * ->asNaturalLanguage() returns the entire schedule in natural language form.
    *
    * In the next and previous functions, <datetime> can be a UNIX timestamp, an ISO string or an array format such as returned by
    * next() and previous().
    *
    * Copyright: 2012 Joost Brugman ([email protected], [email protected])
    *
    * This file is part of the Streamline plugin "StreamlineFoundation" and referenced in the next paragraphs inside this comment block as "this
    * plugin". It is based on the Streamline application framework.
    *
    * This plugin is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as
    * published by the Free Software Foundation, either version 3 of the License, or any later version. This plugin is distributed in the
    * hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
    * PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public
    * License along with Streamline. If not, see <http://www.gnu.org/licenses/>.
    */

    class CronSchedule
    {
    // The actual minutes, hours, daysOfMonth, months, daysOfWeek and years selected by the provided cron specification.
    private $_minutes = array();
    private $_hours = array();
    private $_daysOfMonth = array();
    private $_months = array();
    private $_daysOfWeek = array();
    private $_years = array();

    // The original cron specification in compiled form.
    private $_cronMinutes = array();
    private $_cronHours = array();
    private $_cronDaysOfMonth = array();
    private $_cronMonths = array();
    private $_cronDaysOfWeek = array();
    private $_cronYears = array();

    // The language table
    private $_lang = FALSE;


    /**
    * Minimum and maximum years to cope with the Year 2038 problem in UNIX. We run PHP which most likely runs on a UNIX environment so we
    * must assume vulnerability.
    */
    protected $RANGE_YEARS_MIN = 1970; // Must match date range supported by date(). See also: http://en.wikipedia.org/wiki/Year_2038_problem
    protected $RANGE_YEARS_MAX = 2037; // Must match date range supported by date(). See also: http://en.wikipedia.org/wiki/Year_2038_problem


    /**
    * Function: __construct
    *
    * Description: Performs only base initialization, including language initialization.
    *
    * Parameters: $language The languagecode of the chosen language.
    */
    public function __construct($language = 'en')
    {
    $this->initLang($language);
    }

    //
    // Function: fromCronString
    //
    // Description: Creates a new Schedule object based on a Cron specification.
    //
    // Parameters: $cronSpec A string containing a cron specification.
    // $language The language to use to create a natural language representation of the string
    //
    // Result: A new Schedule object. An \Exception is thrown if the specification is invalid.
    //

    final public static function fromCronString($cronSpec = '* * * * * *', $language = 'en')
    {

    // Split input liberal. Single or multiple Spaces, Tabs and Newlines are all allowed as separators.
    if(count($elements = preg_split('/\s+/', $cronSpec)) < 5)
    throw new Exception('Invalid specification.');

    /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    // Named ranges in cron entries
    /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    $arrMonths = array('JAN' => 1, 'FEB' => 2, 'MAR' => 3, 'APR' => 4, 'MAY' => 5, 'JUN' => 6, 'JUL' => 7, 'AUG' => 8, 'SEP' => 9, 'OCT' => 10, 'NOV' => 11, 'DEC' => 12);
    $arrDaysOfWeek = array('SUN' => 0, 'MON' => 1, 'TUE' => 2, 'WED' => 3, 'THU' => 4, 'FRI' => 5, 'SAT' => 6);


    // Translate the cron specification into arrays that hold specifications of the actual dates
    $newCron = new CronSchedule($language);
    $newCron->_cronMinutes = $newCron->cronInterpret($elements[0], 0, 59, array(), 'minutes');
    $newCron->_cronHours = $newCron->cronInterpret($elements[1], 0, 23, array(), 'hours');
    $newCron->_cronDaysOfMonth = $newCron->cronInterpret($elements[2], 1, 31, array(), 'daysOfMonth');
    $newCron->_cronMonths = $newCron->cronInterpret($elements[3], 1, 12, $arrMonths, 'months');
    $newCron->_cronDaysOfWeek = $newCron->cronInterpret($elements[4], 0, 6, $arrDaysOfWeek, 'daysOfWeek');


    $newCron->_minutes = $newCron->cronCreateItems($newCron->_cronMinutes);
    $newCron->_hours = $newCron->cronCreateItems($newCron->_cronHours);
    $newCron->_daysOfMonth = $newCron->cronCreateItems($newCron->_cronDaysOfMonth);
    $newCron->_months = $newCron->cronCreateItems($newCron->_cronMonths);
    $newCron->_daysOfWeek = $newCron->cronCreateItems($newCron->_cronDaysOfWeek);

    if (isset($elements[5])) {
    $newCron->_cronYears = $newCron->cronInterpret($elements[5], $newCron->RANGE_YEARS_MIN, $newCron->RANGE_YEARS_MAX, array(), 'years');
    $newCron->_years = $newCron->cronCreateItems($newCron->_cronYears);
    }

    return $newCron;
    }


    /*
    * Function: cronInterpret
    *
    * Description: Interprets a single field from a cron specification. Throws an \Exception if the specification is in some way invalid.
    *
    * Parameters: $specification The actual text from the spefication, such as 12-38/3
    * $rangeMin The lowest value for specification.
    * $rangeMax The highest value for specification
    * $namesItems A key/value pair where value is a value between $rangeMin and $rangeMax and key is the name for that value.
    * $errorName The name of the category to use in case of an error.
    *
    * Result: An array with entries, each of which is an array with the following fields:
    * 'number1' The first number of the range or the number specified
    * 'number2' The second number of the range if a range is specified
    * 'hasInterval' TRUE if a range is specified. FALSE otherwise
    * 'interval' The interval if a range is specified.
    */
    final private function cronInterpret($specification, $rangeMin, $rangeMax, $namedItems, $errorName)
    {

    if((!is_string($specification)) && (!(is_int($specification))))
    throw new Exception('Invalid specification.');


    // Multiple values, separated by comma
    $specs = array();
    $specs['rangeMin'] = $rangeMin;
    $specs['rangeMax'] = $rangeMax;
    $specs['elements'] = array();
    $arrSegments = explode(',', $specification);
    foreach($arrSegments as $segment)
    {
    $hasRange = (($posRange = strpos($segment, '-')) !== FALSE);
    $hasInterval = (($posIncrement = strpos($segment, '/')) !== FALSE);

    /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    // Check: Increment without range is invalid

    //if(!$hasRange && $hasInterval) throw new \Exception("Invalid Range ($errorName).");


    // Check: Increment must be final specification

    if($hasRange && $hasInterval)
    if($posIncrement < $posRange) throw new \Exception("Invalid order ($errorName).");


    // GetSegments

    $segmentNumber1 = $segment;
    $segmentNumber2 = '';
    $segmentIncrement = '';
    $intIncrement = 1;
    if($hasInterval)
    {
    $segmentNumber1 = substr($segment, 0, $posIncrement);
    $segmentIncrement = substr($segment, $posIncrement + 1);
    }

    if($hasRange)
    {
    $segmentNumber2 = substr($segmentNumber1, $posRange + 1);
    $segmentNumber1 = substr($segmentNumber1, 0, $posRange);
    }


    // Get and validate first value in range

    if($segmentNumber1 == '*')
    {
    $intNumber1 = $rangeMin;
    $intNumber2 = $rangeMax;
    $hasRange = TRUE;
    }
    else
    {
    if(array_key_exists(strtoupper($segmentNumber1), $namedItems)) $segmentNumber1 = $namedItems[strtoupper($segmentNumber1)];
    if(((string) ($intNumber1 = (int) $segmentNumber1)) != $segmentNumber1) throw new \Exception("Invalid symbol ($errorName).");
    if(($intNumber1 < $rangeMin) || ($intNumber1 > $rangeMax)) throw new \Exception("Out of bounds ($errorName).");


    // Get and validate second value in range

    if($hasRange)
    {
    if(array_key_exists(strtoupper($segmentNumber2), $namedItems)) $segmentNumber2 = $namedItems[strtoupper($segmentNumber2)];
    if(((string) ($intNumber2 = (int) $segmentNumber2)) != $segmentNumber2) throw new \Exception("Invalid symbol ($errorName).");
    if(($intNumber2 < $rangeMin) || ($intNumber2 > $rangeMax)) throw new \Exception("Out of bounds ($errorName).");
    if($intNumber1 > $intNumber2) throw new \Exception("Invalid range ($errorName).");
    }
    }


    // Get and validate increment

    if($hasInterval)
    {
    if(($intIncrement = (int) $segmentIncrement) != $segmentIncrement) throw new \Exception("Invalid symbol ($errorName).");
    if($intIncrement < 1) throw new \Exception("Out of bounds ($errorName).");
    }


    // Apply range and increment

    $elem = array();
    $elem['number1'] = $intNumber1;
    $elem['hasInterval'] = $hasRange;
    if($hasRange)
    {
    $elem['number2'] = $intNumber2;
    $elem['interval'] = $intIncrement;
    }
    $specs['elements'][] = $elem;
    }

    return $specs;
    }


    //
    // Function: cronCreateItems
    //
    // Description: Uses the interpreted cron specification of a single item from a cron specification to create an array with keys that match the
    // selected items.
    //
    // Parameters: $cronInterpreted The interpreted specification
    //
    // Result: An array where each key identifies a matching entry. E.g. the cron specification */10 for minutes will yield an array
    // [0] => 1
    // [10] => 1
    // [20] => 1
    // [30] => 1
    // [40] => 1
    // [50] => 1
    //

    final private function cronCreateItems($cronInterpreted)
    {
    $items = array();

    foreach($cronInterpreted['elements'] as $elem)
    {
    if(!$elem['hasInterval'])
    $items[$elem['number1']] = TRUE;
    else
    for($number = $elem['number1']; $number <= $elem['number2']; $number += $elem['interval'])
    $items[$number] = TRUE;
    }
    ksort($items);
    return $items;
    }


    //
    // Function: dtFromParameters
    //
    // Description: Transforms a flexible parameter passing of a datetime specification into an internally used array.
    //
    // Parameters: $time If a string interpreted as a datetime string in the YYYY-MM-DD HH:II format and other parameters ignored.
    // If an array $minute, $hour, $day, $month and $year are passed as keys 0-4 and other parameters ignored.
    // If a string, interpreted as unix time.
    // If omitted or specified FALSE, defaults to the current time.
    //
    // Result: An array with indices 0-4 holding the actual interpreted values for $minute, $hour, $day, $month and $year.
    //

    final private function dtFromParameters($time = FALSE)
    {
    if($time === FALSE)
    {
    $arrTime = getDate();
    return array($arrTime['minutes'], $arrTime['hours'], $arrTime['mday'], $arrTime['mon'], $arrTime['year']);
    }
    elseif(is_array($time))
    return $time;
    elseif(is_string($time))
    {
    $arrTime = getDate(strtotime($time));
    return array($arrTime['minutes'], $arrTime['hours'], $arrTime['mday'], $arrTime['mon'], $arrTime['year']);
    }elseif(is_int($time))
    {
    $arrTime = getDate($time);
    return array($arrTime['minutes'], $arrTime['hours'], $arrTime['mday'], $arrTime['mon'], $arrTime['year']);
    }
    }

    final private function dtAsString($arrDt)
    {
    if($arrDt === FALSE)
    return FALSE;
    return $arrDt[4].'-'.(strlen($arrDt[3]) == 1 ? '0' : '').$arrDt[3].'-'.(strlen($arrDt[2]) == 1 ? '0' : '').$arrDt[2].' '.(strlen($arrDt[1]) == 1 ? '0' : '').$arrDt[1].':'.(strlen($arrDt[0]) == 1 ? '0' : '').$arrDt[0].':00';
    }


    //
    // Function: match
    //
    // Description: Returns TRUE if the specified date and time corresponds to a scheduled point in time. FALSE otherwise.
    //
    // Parameters: $time If a string interpreted as a datetime string in the YYYY-MM-DD HH:II format and other parameters ignored.
    // If an array $minute, $hour, $day, $month and $year are passed as keys 0-4 and other parameters ignored.
    // If a string, interpreted as unix time.
    // If omitted or specified FALSE, defaults to the current time.
    //
    // Result: TRUE if the schedule matches the specified datetime. FALSE otherwise.
    //

    final public function match($time = FALSE)
    {

    // Convert parameters to array datetime

    $arrDT = $this->dtFromParameters($time);


    // Verify match


    // Years
    if(!array_key_exists($arrDT[4], $this->_years)) return FALSE;
    // Day of week
    if(!array_key_exists(date('w', strtotime($arrDT[4].'-'.$arrDT[3].'-'.$arrDT[2])), $this->_daysOfWeek)) return FALSE;
    // Month
    if(!array_key_exists($arrDT[3], $this->_months)) return FALSE;
    // Day of month
    if(!array_key_exists($arrDT[2], $this->_daysOfMonth)) return FALSE;
    // Hours
    if(!array_key_exists($arrDT[1], $this->_hours)) return FALSE;
    // Minutes
    if(!array_key_exists($arrDT[0], $this->_minutes)) return FALSE;

    return TRUE;
    }


    //
    // Function: next
    //
    // Description: Acquires the first scheduled datetime beyond the provided one.
    //
    // Parameters: $time If a string interpreted as a datetime string in the YYYY-MM-DD HH:II format and other parameters ignored.
    // If an array $minute, $hour, $day, $month and $year are passed as keys 0-4 and other parameters ignored.
    // If a string, interpreted as unix time.
    // If omitted or specified FALSE, defaults to the current time.
    //
    // Result: An array with the following keys:
    // 0 Next scheduled minute
    // 1 Next scheduled hour
    // 2 Next scheduled date
    // 3 Next scheduled month
    // 4 Next scheduled year
    //

    final public function next($time = FALSE)
    {

    // Convert parameters to array datetime

    $arrDT = $this->dtFromParameters($time);

    while(1)
    {

    // Verify the current date is in range. If not, move into range and consider this the next position

    if(!array_key_exists($arrDT[4], $this->_years))
    {
    if(($arrDT[4] = $this->getEarliestItem($this->_years, $arrDT[4], FALSE)) === FALSE)
    return FALSE;
    $arrDT[3] = $this->getEarliestItem($this->_months);
    $arrDT[2] = $this->getEarliestItem($this->_daysOfMonth);
    $arrDT[1] = $this->getEarliestItem($this->_hours);
    $arrDT[0] = $this->getEarliestItem($this->_minutes);
    break;
    } elseif(!array_key_exists($arrDT[3], $this->_months))
    {
    $arrDT[3] = $this->getEarliestItem($this->_months, $arrDT[3]);
    $arrDT[2] = $this->getEarliestItem($this->_daysOfMonth);
    $arrDT[1] = $this->getEarliestItem($this->_hours);
    $arrDT[0] = $this->getEarliestItem($this->_minutes);
    break;
    } elseif(!array_key_exists($arrDT[2], $this->_daysOfMonth))
    {
    $arrDT[2] = $this->getEarliestItem($this->_daysOfMonth, $arrDT[2]);
    $arrDT[1] = $this->getEarliestItem($this->_hours);
    $arrDT[0] = $this->getEarliestItem($this->_minutes);
    break;
    } elseif(!array_key_exists($arrDT[1], $this->_hours))
    {
    $arrDT[1] = $this->getEarliestItem($this->_hours, $arrDT[1]);
    $arrDT[0] = $this->getEarliestItem($this->_minutes);
    break;
    } elseif(!array_key_exists($arrDT[1], $this->_hours))
    {
    $arrDT[0] = $this->getEarliestItem($this->_minutes, $arrDT[0]);
    break;
    }


    // Advance minute, hour, date, month and year while overflowing.

    $daysInThisMonth = date('t', strtotime($arrDT[4].'-'.$arrDT[3]));
    if($this->advanceItem($this->_minutes, 0, 59, $arrDT[0]))
    if($this->advanceItem($this->_hours, 0, 23, $arrDT[1]))
    if($this->advanceItem($this->_daysOfMonth, 0, $daysInThisMonth, $arrDT[2]))
    if($this->advanceItem($this->_months, 1, 12, $arrDT[3]))
    if($this->advanceItem($this->_years, $this->RANGE_YEARS_MIN, $this->RANGE_YEARS_MAX, $arrDT[4]))
    return FALSE;
    break;
    }


    // If Datetime now points to a day that is schedule then return.

    $dayOfWeek = date('w', strtotime($this->dtAsString($arrDT)));
    if(array_key_exists($dayOfWeek, $this->_daysOfWeek))
    return $arrDT;


    // Otherwise move to next scheduled date

    return $this->next($arrDT);
    }

    final public function nextAsString($time = FALSE)
    {
    return $this->dtAsString($this->next($time));
    }

    final public function nextAsTime($time = FALSE)
    {
    return strtotime($this->dtAsString($this->next($time)));
    }


    //
    // Function: advanceItem
    //
    // Description: Advances the current item to the next one (the next minute, the next hour, etc.).
    //
    // Parameters: $arrItems A reference to the collection in which to advance.
    // $rangeMin The lowest possible value for $current.
    // $rangeMax The highest possible value for $current
    // $current The index that is being incremented.
    //
    // Result: FALSE if current did not overflow (reset back to the earliest possible value). TRUE if it did.
    //

    final private function advanceItem($arrItems, $rangeMin, $rangeMax, & $current)
    {

    // Advance pointer

    $current++;


    // If still before start, move to earliest

    if($current < $rangeMin)
    $current = $this->getEarliestItem($arrItems);


    // Parse items until found or overflow

    for(;$current <= $rangeMax; $current++)
    if(array_key_exists($current, $arrItems))
    return FALSE; // We did not overflow


    // Or overflow

    $current = $this->getEarliestItem($arrItems);
    return TRUE;
    }


    //
    // Function: getEarliestItem
    //
    // Description: Retrieves the earliest item in a collection, e.g. the earliest minute or the earliest month.
    //
    // Parameters: $arrItems A reference to the collection in which to search.
    // $afterItem The highest index that is to be skipped.
    //

    final private function getEarliestItem($arrItems, $afterItem = FALSE, $allowOverflow = TRUE)
    {

    // If no filter is specified, return the earliest listed item.

    if($afterItem === FALSE)
    {
    reset($arrItems);
    return key($arrItems);
    }


    // Or parse until we passed $afterItem

    foreach($arrItems as $key => $value)
    if($key > $afterItem)
    return $key;


    // If still nothing found, we may have exhausted our options.

    if(!$allowOverflow)
    return FALSE;
    reset($arrItems);
    return key($arrItems);
    }


    //
    // Function: previous
    //
    // Description: Acquires the first scheduled datetime before the provided one.
    //
    // Parameters: $time If a string interpreted as a datetime string in the YYYY-MM-DD HH:II format and other parameters ignored.
    // If an array $minute, $hour, $day, $month and $year are passed as keys 0-4 and other parameters ignored.
    // If a string, interpreted as unix time.
    // If omitted or specified FALSE, defaults to the current time.
    //
    // Result: An array with the following keys:
    // 0 Previous scheduled minute
    // 1 Previous scheduled hour
    // 2 Previous scheduled date
    // 3 Previous scheduled month
    // 4 Previous scheduled year
    //

    final public function previous($time = FALSE)
    {

    // Convert parameters to array datetime

    $arrDT = $this->dtFromParameters($time);

    while(1)
    {

    // Verify the current date is in range. If not, move into range and consider this the previous position

    if(!array_key_exists($arrDT[4], $this->_years))
    {
    if(($arrDT[4] = $this->getLatestItem($this->_years, $arrDT[4], FALSE)) === FALSE)
    return FALSE;
    $arrDT[3] = $this->getLatestItem($this->_months);
    $arrDT[2] = $this->getLatestItem($this->_daysOfMonth);
    $arrDT[1] = $this->getLatestItem($this->_hours);
    $arrDT[0] = $this->getLatestItem($this->_minutes);
    break;
    } elseif(!array_key_exists($arrDT[3], $this->_months))
    {
    $arrDT[3] = $this->getLatestItem($this->_months, $arrDT[3]);
    $arrDT[2] = $this->getLatestItem($this->_daysOfMonth);
    $arrDT[1] = $this->getLatestItem($this->_hours);
    $arrDT[0] = $this->getLatestItem($this->_minutes);
    break;
    } elseif(!array_key_exists($arrDT[2], $this->_daysOfMonth))
    {
    $arrDT[2] = $this->getLatestItem($this->_daysOfMonth, $arrDT[2]);
    $arrDT[1] = $this->getLatestItem($this->_hours);
    $arrDT[0] = $this->getLatestItem($this->_minutes);
    break;
    } elseif(!array_key_exists($arrDT[1], $this->_hours))
    {
    $arrDT[1] = $this->getLatestItem($this->_hours, $arrDT[1]);
    $arrDT[0] = $this->getLatestItem($this->_minutes);
    break;
    } elseif(!array_key_exists($arrDT[1], $this->_hours))
    {
    $arrDT[0] = $this->getLatestItem($this->_minutes, $arrDT[0]);
    break;
    }


    // Recede minute, hour, date, month and year while overflowing.

    $daysInPreviousMonth = date('t', strtotime('-1 month', strtotime($arrDT[4].'-'.$arrDT[3])));
    if($this->recedeItem($this->_minutes, 0, 59, $arrDT[0]))
    if($this->recedeItem($this->_hours, 0, 23, $arrDT[1]))
    if($this->recedeItem($this->_daysOfMonth, 0, $daysInPreviousMonth, $arrDT[2]))
    if($this->recedeItem($this->_months, 1, 12, $arrDT[3]))
    if($this->recedeItem($this->_years, $this->RANGE_YEARS_MIN, $this->RANGE_YEARS_MAX, $arrDT[4]))
    return FALSE;
    break;
    }


    // If Datetime now points to a day that is schedule then return.

    $dayOfWeek = date('w', strtotime($this->dtAsString($arrDT)));
    if(array_key_exists($dayOfWeek, $this->_daysOfWeek))
    return $arrDT;


    // Otherwise move to next scheduled date

    return $this->previous($arrDT);
    }

    final public function previousAsString($time = FALSE)
    {
    return $this->dtAsString($this->previous($time));
    }

    final public function previousAsTime($time = FALSE)
    {
    return strtotime($this->dtAsString($this->previous($time)));
    }


    //
    // Function: recedeItem
    //
    // Description: Recedes the current item to the previous one (the previous minute, the previous hour, etc.).
    //
    // Parameters: $arrItems A reference to the collection in which to recede.
    // $rangeMin The lowest possible value for $current.
    // $rangeMax The highest possible value for $current
    // $current The index that is being decremented.
    //
    // Result: FALSE if current did not overflow (reset back to the highest possible value). TRUE if it did.
    //

    final private function recedeItem($arrItems, $rangeMin, $rangeMax, & $current)
    {

    // Recede pointer

    $current--;


    // If still above highest, move to highest

    if($current > $rangeMax)
    $current = $this->getLatestItem($arrItems, $rangeMax + 1);


    // Parse items until found or overflow

    for(;$current >= $rangeMin; $current--)
    if(array_key_exists($current, $arrItems))
    return FALSE; // We did not overflow


    // Or overflow

    $current = $this->getLatestItem($arrItems, $rangeMax + 1);
    return TRUE;
    }


    //
    // Function: getLatestItem
    //
    // Description: Retrieves the latest item in a collection, e.g. the latest minute or the latest month.
    //
    // Parameters: $arrItems A reference to the collection in which to search.
    // $beforeItem The lowest index that is to be skipped.
    //

    final private function getLatestItem($arrItems, $beforeItem = FALSE, $allowOverflow = TRUE)
    {

    // If no filter is specified, return the latestlisted item.

    if($beforeItem === FALSE)
    {
    end($arrItems);
    return key($arrItems);
    }


    // Or parse until we passed $beforeItem

    end($arrItems);
    do
    {
    if(($key = key($arrItems)) < $beforeItem)
    return $key;
    } while(prev($arrItems));


    // If still nothing found, we may have exhausted our options.

    if(!$allowOverflow)
    return FALSE;
    end($arrItems);
    return key($arrItems);
    }



    //
    // Function:
    //
    // Description:
    //
    // Parameters:
    //
    // Result:
    //

    final private function getClass($spec)
    {
    if(!$this->classIsSpecified($spec)) return '0';
    if($this->classIsSingleFixed($spec)) return '1';
    return '2';
    }


    //
    // Function:
    //
    // Description: Returns TRUE if the Cron Specification is specified. FALSE otherwise. This is true if the specification has more than one entry
    // or is anything than the entire approved range ("*").
    //
    // Parameters:
    //
    // Result:
    //

    final private function classIsSpecified($spec)
    {
    if($spec['elements'][0]['hasInterval'] == FALSE) return TRUE;
    if($spec['elements'][0]['number1'] != $spec['rangeMin']) return TRUE;
    if($spec['elements'][0]['number2'] != $spec['rangeMax']) return TRUE;
    if($spec['elements'][0]['interval'] != 1) return TRUE;
    return FALSE;
    }


    //
    // Function:
    //
    // Description: Returns TRUE if the Cron Specification is specified as a single value. FALSE otherwise. This is true only if there is only
    // one entry and the entry is only a single number (e.g. "10")
    //
    // Parameters:
    //
    // Result:
    //

    final private function classIsSingleFixed($spec)
    {
    return (count($spec['elements']) == 1) && (!$spec['elements'][0]['hasInterval']);
    }

    final private function initLang($language = 'en')
    {
    switch($language)
    {
    case 'en':
    $this->_lang['elemMin: at_the_hour'] = 'at the hour';
    $this->_lang['elemMin: after_the_hour_every_X_minute'] = 'every minute';
    $this->_lang['elemMin: after_the_hour_every_X_minute_plural'] = 'every @1 minutes';
    $this->_lang['elemMin: every_consecutive_minute'] = 'every consecutive minute';
    $this->_lang['elemMin: every_consecutive_minute_plural'] = 'every consecutive @1 minutes';
    $this->_lang['elemMin: every_minute'] = 'every minute';
    $this->_lang['elemMin: between_X_and_Y'] = 'from the @1 to the @2';
    $this->_lang['elemMin: at_X:Y'] = 'At @1:@2';
    $this->_lang['elemHour: past_X:00'] = 'past @1:00';
    $this->_lang['elemHour: between_X:00_and_Y:59'] = 'between @1:00 and @2:59';
    $this->_lang['elemHour: in_the_60_minutes_past_'] = 'in the 60 minutes past every consecutive hour';
    $this->_lang['elemHour: in_the_60_minutes_past__plural'] = 'in the 60 minutes past every consecutive @1 hours';
    $this->_lang['elemHour: past_every_consecutive_'] = 'past every consecutive hour';
    $this->_lang['elemHour: past_every_consecutive__plural'] = 'past every consecutive @1 hours';
    $this->_lang['elemHour: past_every_hour'] = 'past every hour';
    $this->_lang['elemDOM: the_X'] = 'the @1';
    $this->_lang['elemDOM: every_consecutive_day'] = 'every consecutive day';
    $this->_lang['elemDOM: every_consecutive_day_plural'] = 'every consecutive @1 days';
    $this->_lang['elemDOM: on_every_day'] = 'on every day';
    $this->_lang['elemDOM: between_the_Xth_and_Yth'] = 'between the @1 and the @2';
    $this->_lang['elemDOM: on_the_X'] = 'on the @1';
    $this->_lang['elemDOM: on_X'] = 'on @1';
    $this->_lang['elemMonth: every_X'] = 'every @1';
    $this->_lang['elemMonth: every_consecutive_month'] = 'every consecutive month';
    $this->_lang['elemMonth: every_consecutive_month_plural'] = 'every consecutive @1 months';
    $this->_lang['elemMonth: between_X_and_Y'] = 'from @1 to @2';
    $this->_lang['elemMonth: of_every_month'] = 'of every month';
    $this->_lang['elemMonth: during_every_X'] = 'during every @1';
    $this->_lang['elemMonth: during_X'] = 'during @1';
    $this->_lang['elemYear: in_X'] = 'in @1';
    $this->_lang['elemYear: every_consecutive_year'] = 'every consecutive year';
    $this->_lang['elemYear: every_consecutive_year_plural'] = 'every consecutive @1 years';
    $this->_lang['elemYear: from_X_through_Y'] = 'from @1 through @2';
    $this->_lang['elemDOW: on_every_day'] = 'on every day';
    $this->_lang['elemDOW: on_X'] = 'on @1';
    $this->_lang['elemDOW: but_only_on_X'] = 'but only if the event takes place on @1';
    $this->_lang['separator_and'] = 'and';
    $this->_lang['separator_or'] = 'or';
    $this->_lang['day: 0_plural'] = 'Sundays';
    $this->_lang['day: 1_plural'] = 'Mondays';
    $this->_lang['day: 2_plural'] = 'Tuesdays';
    $this->_lang['day: 3_plural'] = 'Wednesdays';
    $this->_lang['day: 4_plural'] = 'Thursdays';
    $this->_lang['day: 5_plural'] = 'Fridays';
    $this->_lang['day: 6_plural'] = 'Saturdays';
    $this->_lang['month: 1'] = 'January';
    $this->_lang['month: 2'] = 'February';
    $this->_lang['month: 3'] = 'March';
    $this->_lang['month: 4'] = 'April';
    $this->_lang['month: 5'] = 'May';
    $this->_lang['month: 6'] = 'June';
    $this->_lang['month: 7'] = 'July';
    $this->_lang['month: 8'] = 'Augustus';
    $this->_lang['month: 9'] = 'September';
    $this->_lang['month: 10'] = 'October';
    $this->_lang['month: 11'] = 'November';
    $this->_lang['month: 12'] = 'December';
    $this->_lang['ordinal: 1'] = '1st';
    $this->_lang['ordinal: 2'] = '2nd';
    $this->_lang['ordinal: 3'] = '3rd';
    $this->_lang['ordinal: 4'] = '4th';
    $this->_lang['ordinal: 5'] = '5th';
    $this->_lang['ordinal: 6'] = '6th';
    $this->_lang['ordinal: 7'] = '7th';
    $this->_lang['ordinal: 8'] = '8th';
    $this->_lang['ordinal: 9'] = '9th';
    $this->_lang['ordinal: 10'] = '10th';
    $this->_lang['ordinal: 11'] = '11th';
    $this->_lang['ordinal: 12'] = '12th';
    $this->_lang['ordinal: 13'] = '13th';
    $this->_lang['ordinal: 14'] = '14th';
    $this->_lang['ordinal: 15'] = '15th';
    $this->_lang['ordinal: 16'] = '16th';
    $this->_lang['ordinal: 17'] = '17th';
    $this->_lang['ordinal: 18'] = '18th';
    $this->_lang['ordinal: 19'] = '19th';
    $this->_lang['ordinal: 20'] = '20th';
    $this->_lang['ordinal: 21'] = '21st';
    $this->_lang['ordinal: 22'] = '22nd';
    $this->_lang['ordinal: 23'] = '23rd';
    $this->_lang['ordinal: 24'] = '24th';
    $this->_lang['ordinal: 25'] = '25th';
    $this->_lang['ordinal: 26'] = '26th';
    $this->_lang['ordinal: 27'] = '27th';
    $this->_lang['ordinal: 28'] = '28th';
    $this->_lang['ordinal: 29'] = '29th';
    $this->_lang['ordinal: 30'] = '30th';
    $this->_lang['ordinal: 31'] = '31st';
    $this->_lang['ordinal: 32'] = '32nd';
    $this->_lang['ordinal: 33'] = '33rd';
    $this->_lang['ordinal: 34'] = '34th';
    $this->_lang['ordinal: 35'] = '35th';
    $this->_lang['ordinal: 36'] = '36th';
    $this->_lang['ordinal: 37'] = '37th';
    $this->_lang['ordinal: 38'] = '38th';
    $this->_lang['ordinal: 39'] = '39th';
    $this->_lang['ordinal: 40'] = '40th';
    $this->_lang['ordinal: 41'] = '41st';
    $this->_lang['ordinal: 42'] = '42nd';
    $this->_lang['ordinal: 43'] = '43rd';
    $this->_lang['ordinal: 44'] = '44th';
    $this->_lang['ordinal: 45'] = '45th';
    $this->_lang['ordinal: 46'] = '46th';
    $this->_lang['ordinal: 47'] = '47th';
    $this->_lang['ordinal: 48'] = '48th';
    $this->_lang['ordinal: 49'] = '49th';
    $this->_lang['ordinal: 50'] = '50th';
    $this->_lang['ordinal: 51'] = '51st';
    $this->_lang['ordinal: 52'] = '52nd';
    $this->_lang['ordinal: 53'] = '53rd';
    $this->_lang['ordinal: 54'] = '54th';
    $this->_lang['ordinal: 55'] = '55th';
    $this->_lang['ordinal: 56'] = '56th';
    $this->_lang['ordinal: 57'] = '57th';
    $this->_lang['ordinal: 58'] = '58th';
    $this->_lang['ordinal: 59'] = '59th';
    break;

    case 'nl':
    $this->_lang['elemMin: at_the_hour'] = 'op het hele uur';
    $this->_lang['elemMin: after_the_hour_every_X_minute'] = 'elke minuut';
    $this->_lang['elemMin: after_the_hour_every_X_minute_plural'] = 'elke @1 minuten';
    $this->_lang['elemMin: every_consecutive_minute'] = 'elke opeenvolgende minuut';
    $this->_lang['elemMin: every_consecutive_minute_plural'] = 'elke opeenvolgende @1 minuten';
    $this->_lang['elemMin: every_minute'] = 'elke minuut';
    $this->_lang['elemMin: between_X_and_Y'] = 'van de @1 tot en met de @2';
    $this->_lang['elemMin: at_X:Y'] = 'Om @1:@2';
    $this->_lang['elemHour: past_X:00'] = 'na @1:00';
    $this->_lang['elemHour: between_X:00_and_Y:59'] = 'tussen @1:00 en @2:59';
    $this->_lang['elemHour: in_the_60_minutes_past_'] = 'in de 60 minuten na elk opeenvolgend uur';
    $this->_lang['elemHour: in_the_60_minutes_past__plural'] = 'in de 60 minuten na elke opeenvolgende @1 uren';
    $this->_lang['elemHour: past_every_consecutive_'] = 'na elk opeenvolgend uur';
    $this->_lang['elemHour: past_every_consecutive__plural'] = 'na elke opeenvolgende @1 uren';
    $this->_lang['elemHour: past_every_hour'] = 'na elk uur';
    $this->_lang['elemDOM: the_X'] = 'de @1';
    $this->_lang['elemDOM: every_consecutive_day'] = 'elke opeenvolgende dag';
    $this->_lang['elemDOM: every_consecutive_day_plural'] = 'elke opeenvolgende @1 dagen';
    $this->_lang['elemDOM: on_every_day'] = 'op elke dag';
    $this->_lang['elemDOM: between_the_Xth_and_Yth'] = 'tussen de @1 en de @2';
    $this->_lang['elemDOM: on_the_X'] = 'op de @1';
    $this->_lang['elemDOM: on_X'] = 'op @1';
    $this->_lang['elemMonth: every_X'] = 'elke @1';
    $this->_lang['elemMonth: every_consecutive_month'] = 'elke opeenvolgende maand';
    $this->_lang['elemMonth: every_consecutive_month_plural'] = 'elke opeenvolgende @1 maanden';
    $this->_lang['elemMonth: between_X_and_Y'] = 'van @1 tot @2';
    $this->_lang['elemMonth: of_every_month'] = 'van elke maand';
    $this->_lang['elemMonth: during_every_X'] = 'tijdens elke @1';
    $this->_lang['elemMonth: during_X'] = 'tijdens @1';
    $this->_lang['elemYear: in_X'] = 'in @1';
    $this->_lang['elemYear: every_consecutive_year'] = 'elk opeenvolgend jaar';
    $this->_lang['elemYear: every_consecutive_year_plural'] = 'elke opeenvolgende @1 jaren';
    $this->_lang['elemYear: from_X_through_Y'] = 'van @1 tot en met @2';
    $this->_lang['elemDOW: on_every_day'] = 'op elke dag';
    $this->_lang['elemDOW: on_X'] = 'op @1';
    $this->_lang['elemDOW: but_only_on_X'] = 'maar alleen als het plaatsvindt op @1';
    $this->_lang['separator_and'] = 'en';
    $this->_lang['separator_of'] = 'of';
    $this->_lang['day: 0_plural'] = 'zondagen';
    $this->_lang['day: 1_plural'] = 'maandagen';
    $this->_lang['day: 2_plural'] = 'dinsdagen';
    $this->_lang['day: 3_plural'] = 'woensdagen';
    $this->_lang['day: 4_plural'] = 'donderdagen';
    $this->_lang['day: 5_plural'] = 'vrijdagen';
    $this->_lang['day: 6_plural'] = 'zaterdagen';
    $this->_lang['month: 1'] = 'januari';
    $this->_lang['month: 2'] = 'februari';
    $this->_lang['month: 3'] = 'maart';
    $this->_lang['month: 4'] = 'april';
    $this->_lang['month: 5'] = 'mei';
    $this->_lang['month: 6'] = 'juni';
    $this->_lang['month: 7'] = 'juli';
    $this->_lang['month: 8'] = 'augustus';
    $this->_lang['month: 9'] = 'september';
    $this->_lang['month: 10'] = 'october';
    $this->_lang['month: 11'] = 'november';
    $this->_lang['month: 12'] = 'december';
    $this->_lang['ordinal: 1'] = '1e';
    $this->_lang['ordinal: 2'] = '2e';
    $this->_lang['ordinal: 3'] = '3e';
    $this->_lang['ordinal: 4'] = '4e';
    $this->_lang['ordinal: 5'] = '5e';
    $this->_lang['ordinal: 6'] = '6e';
    $this->_lang['ordinal: 7'] = '7e';
    $this->_lang['ordinal: 8'] = '8e';
    $this->_lang['ordinal: 9'] = '9e';
    $this->_lang['ordinal: 10'] = '10e';
    $this->_lang['ordinal: 11'] = '11e';
    $this->_lang['ordinal: 12'] = '12e';
    $this->_lang['ordinal: 13'] = '13e';
    $this->_lang['ordinal: 14'] = '14e';
    $this->_lang['ordinal: 15'] = '15e';
    $this->_lang['ordinal: 16'] = '16e';
    $this->_lang['ordinal: 17'] = '17e';
    $this->_lang['ordinal: 18'] = '18e';
    $this->_lang['ordinal: 19'] = '19e';
    $this->_lang['ordinal: 20'] = '20e';
    $this->_lang['ordinal: 21'] = '21e';
    $this->_lang['ordinal: 22'] = '22e';
    $this->_lang['ordinal: 23'] = '23e';
    $this->_lang['ordinal: 24'] = '24e';
    $this->_lang['ordinal: 25'] = '25e';
    $this->_lang['ordinal: 26'] = '26e';
    $this->_lang['ordinal: 27'] = '27e';
    $this->_lang['ordinal: 28'] = '28e';
    $this->_lang['ordinal: 29'] = '29e';
    $this->_lang['ordinal: 30'] = '30e';
    $this->_lang['ordinal: 31'] = '31e';
    $this->_lang['ordinal: 32'] = '32e';
    $this->_lang['ordinal: 33'] = '33e';
    $this->_lang['ordinal: 34'] = '34e';
    $this->_lang['ordinal: 35'] = '35e';
    $this->_lang['ordinal: 36'] = '36e';
    $this->_lang['ordinal: 37'] = '37e';
    $this->_lang['ordinal: 38'] = '38e';
    $this->_lang['ordinal: 39'] = '39e';
    $this->_lang['ordinal: 40'] = '40e';
    $this->_lang['ordinal: 41'] = '41e';
    $this->_lang['ordinal: 42'] = '42e';
    $this->_lang['ordinal: 43'] = '43e';
    $this->_lang['ordinal: 44'] = '44e';
    $this->_lang['ordinal: 45'] = '45e';
    $this->_lang['ordinal: 46'] = '46e';
    $this->_lang['ordinal: 47'] = '47e';
    $this->_lang['ordinal: 48'] = '48e';
    $this->_lang['ordinal: 49'] = '49e';
    $this->_lang['ordinal: 50'] = '50e';
    $this->_lang['ordinal: 51'] = '51e';
    $this->_lang['ordinal: 52'] = '52e';
    $this->_lang['ordinal: 53'] = '53e';
    $this->_lang['ordinal: 54'] = '54e';
    $this->_lang['ordinal: 55'] = '55e';
    $this->_lang['ordinal: 56'] = '56e';
    $this->_lang['ordinal: 57'] = '57e';
    $this->_lang['ordinal: 58'] = '58e';
    $this->_lang['ordinal: 59'] = '59e';
    break;
    }
    }

    final private function natlangPad2($number)
    {
    return (strlen($number) == 1 ? '0' : '').$number;
    }

    final private function natlangApply($id, $p1 = FALSE, $p2 = FALSE, $p3 = FALSE, $p4 = FALSE, $p5 = FALSE, $p6 = FALSE)
    {
    $txt = $this->_lang[$id];

    if($p1 !== FALSE) $txt = str_replace('@1', $p1, $txt);
    if($p2 !== FALSE) $txt = str_replace('@2', $p2, $txt);
    if($p3 !== FALSE) $txt = str_replace('@3', $p3, $txt);
    if($p4 !== FALSE) $txt = str_replace('@4', $p4, $txt);
    if($p5 !== FALSE) $txt = str_replace('@5', $p5, $txt);
    if($p6 !== FALSE) $txt = str_replace('@6', $p6, $txt);

    return $txt;
    }


    //
    // Function: natlangRange
    //
    // Description: Converts a range into natural language
    //
    // Parameters:
    //
    // Result:
    //

    final private function natlangRange($spec, $entryFunction, $p1 = FALSE)
    {
    $arrIntervals = array();
    foreach($spec['elements'] as $elem)
    $arrIntervals[] = call_user_func($entryFunction, $elem, $p1);

    $txt = "";
    for($index = 0; $index < count($arrIntervals); $index++)
    $txt .= ($index == 0 ? '' : ($index == (count($arrIntervals) - 1) ? ' '.$this->natlangApply('separator_and').' ' : ', ')).$arrIntervals[$index];
    return $txt;
    }


    //
    // Function: natlangElementMinute
    //
    // Description: Converts an entry from the minute specification to natural language.
    //

    final private function natlangElementMinute($elem)
    {
    if(!$elem['hasInterval'])
    {
    if($elem['number1'] == 0) return $this->natlangApply('elemMin: at_the_hour');
    else return $this->natlangApply('elemMin: after_the_hour_every_X_minute'.($elem['number1'] == 1 ? '' : '_plural'), $elem['number1']);
    }

    $txt = $this->natlangApply('elemMin: every_consecutive_minute'.($elem['interval'] == 1 ? '' : '_plural'), $elem['interval']);
    if(($elem['number1'] != $this->_cronMinutes['rangeMin']) || ($elem['number2'] != $this->_cronMinutes['rangeMax']))
    $txt .= ' ('.$this->natlangApply('elemMin: between_X_and_Y', $this->natlangApply('ordinal: '.$elem['number1']), $this->natlangApply('ordinal: '.$elem['number2'])).')';
    return $txt;
    }


    //
    // Function: natlangElementHour
    //
    // Description: Converts an entry from the hour specification to natural language.
    //

    final private function natlangElementHour($elem, $asBetween)
    {
    if(!$elem['hasInterval'])
    {
    if($asBetween) return $this->natlangApply('elemHour: between_X:00_and_Y:59', $this->natlangPad2($elem['number1']), $this->natlangPad2($elem['number1']));
    else return $this->natlangApply('elemHour: past_X:00', $this->natlangPad2($elem['number1']));
    }

    if($asBetween) $txt = $this->natlangApply('elemHour: in_the_60_minutes_past_'.($elem['interval'] == 1 ? '' : '_plural'), $elem['interval']);
    else $txt = $this->natlangApply('elemHour: past_every_consecutive_'.($elem['interval'] == 1 ? '' : '_plural'), $elem['interval']);

    if(($elem['number1'] != $this->_cronHours['rangeMin']) || ($elem['number2'] != $this->_cronHours['rangeMax']))
    $txt .= ' ('.$this->natlangApply('elemHour: between_X:00_and_Y:59', $elem['number1'], $elem['number2']).')';
    return $txt;
    }


    //
    // Function: natlangElementDayOfMonth
    //
    // Description: Converts an entry from the day of month specification to natural language.
    //

    final private function natlangElementDayOfMonth($elem)
    {
    if(!$elem['hasInterval'])
    return $this->natlangApply('elemDOM: the_X', $this->natlangApply('ordinal: '.$elem['number1']));

    $txt = $this->natlangApply('elemDOM: every_consecutive_day'.($elem['interval'] == 1 ? '' : '_plural'), $elem['interval']);
    if(($elem['number1'] != $this->_cronHours['rangeMin']) || ($elem['number2'] != $this->_cronHours['rangeMax']))
    $txt .= ' ('.$this->natlangApply('elemDOM: between_the_Xth_and_Yth', $this->natlangApply('ordinal: '.$elem['number1']), $this->natlangApply('ordinal: '.$elem['number2'])).')';
    return $txt;
    }


    //
    // Function: natlangElementDayOfMonth
    //
    // Description: Converts an entry from the month specification to natural language.
    //

    final private function natlangElementMonth($elem)
    {
    if(!$elem['hasInterval'])
    return $this->natlangApply('elemMonth: every_X', $this->natlangApply('month: '.$elem['number1']));

    $txt = $this->natlangApply('elemMonth: every_consecutive_month'.($elem['interval'] == 1 ? '' : '_plural'), $elem['interval']);
    if(($elem['number1'] != $this->_cronMonths['rangeMin']) || ($elem['number2'] != $this->_cronMonths['rangeMax']))
    $txt .= ' ('.$this->natlangApply('elemMonth: between_X_and_Y', $this->natlangApply('month: '.$elem['number1']), $this->natlangApply('month: '.$elem['number2'])).')';
    return $txt;
    }


    //
    // Function: natlangElementYear
    //
    // Description: Converts an entry from the year specification to natural language.
    //

    final private function natlangElementYear($elem)
    {
    if(!$elem['hasInterval'])
    return $elem['number1'];

    $txt = $this->natlangApply('elemYear: every_consecutive_year'.($elem['interval'] == 1 ? '' : '_plural'), $elem['interval']);
    if(($elem['number1'] != $this->_cronMonths['rangeMin']) || ($elem['number2'] != $this->_cronMonths['rangeMax']))
    $txt .= ' ('.$this->natlangApply('elemYear: from_X_through_Y', $elem['number1'], $elem['number2']).')';
    return $txt;
    }


    //
    // Function: asNaturalLanguage
    //
    // Description: Returns the current cron specification in natural language.
    //
    // Parameters: None
    //
    // Result: A string containing a natural language text.
    //

    final public function asNaturalLanguage()
    {
    $switchForceDateExplaination = FALSE;
    $switchDaysOfWeekAreExcluding = TRUE;


    // Generate Time String

    $txtMinutes = array();
    $txtMinutes[0] = $this->natlangApply('elemMin: every_minute');
    $txtMinutes[1] = $this->natlangElementMinute($this->_cronMinutes['elements'][0]);
    $txtMinutes[2] = $this->natlangRange($this->_cronMinutes, array($this, 'natlangElementMinute'));

    $txtHours = array();
    $txtHours[0] = $this->natlangApply('elemHour: past_every_hour');
    $txtHours[1] = array();
    $txtHours[1]['between'] = $this->natlangRange($this->_cronHours, array($this, 'natlangElementHour'), TRUE);
    $txtHours[1]['past'] = $this->natlangRange($this->_cronHours, array($this, 'natlangElementHour'), FALSE);
    $txtHours[2] = array();
    $txtHours[2]['between'] = $this->natlangRange($this->_cronHours, array($this, 'natlangElementHour'), TRUE);
    $txtHours[2]['past'] = $this->natlangRange($this->_cronHours, array($this, 'natlangElementHour'), FALSE);

    $classMinutes = $this->getClass($this->_cronMinutes);
    $classHours = $this->getClass($this->_cronHours);

    switch($classMinutes.$classHours)
    {

    // Special case: Unspecified date + Unspecified month
    //
    // Rule: The language for unspecified fields is omitted if a more detailed field has already been explained.
    //
    // The minutes field always yields an explaination, at the very least in the form of 'every minute'. This rule states that if the
    // hour is not specified, it can be omitted because 'every minute' is already sufficiently clear.
    //

    case '00':
    $txtTime = $txtMinutes[0];
    break;


    // Special case: Fixed minutes and fixed hours
    //
    // The default writing would be something like 'every 20 minutes past 04:00', but the more common phrasing would be: At 04:20.
    //
    // We will switch ForceDateExplaination on, so that even a non-specified date yields an explaination (e.g. 'every day')
    //

    case '11':
    $txtTime = $this->natlangApply('elemMin: at_X:Y', $this->natlangPad2($this->_cronHours['elements'][0]['number1']), $this->natlangPad2($this->_cronMinutes['elements'][0]['number1']));
    $switchForceDateExplaination = TRUE;
    break;


    // Special case: Between :00 and :59
    //
    // If hours are specified, but minutes are not, then the minutes string will yield something like 'every minute'. We must the
    // differentiate the hour specification because the minutes specification does not relate to all minutes past the hour, but only to
    // those minutes between :00 and :59
    //
    // We will switch ForceDateExplaination on, so that even a non-specified date yields an explaination (e.g. 'every day')
    //

    case '01':
    case '02':
    $txtTime = $txtMinutes[$classMinutes].' '.$txtHours[$classHours]['between'];
    $switchForceDateExplaination = TRUE;
    break;


    // Special case: Past the hour
    //
    // If minutes are specified and hours are specified, then the specification of minutes is always limited to a maximum of 60 minutes
    // and always applies to the minutes 'past the hour'.
    //
    // We will switch ForceDateExplaination on, so that even a non-specified date yields an explaination (e.g. 'every day')
    //

    case '12':
    case '22':
    case '21':
    $txtTime = $txtMinutes[$classMinutes].' '.$txtHours[$classHours]['past'];
    $switchForceDateExplaination = TRUE;
    break;

    default:
    $txtTime = $txtMinutes[$classMinutes].' '.$txtHours[$classHours];
    break;
    }


    // Generate Date String

    $txtDaysOfMonth = array();
    $txtDaysOfMonth[0] = '';
    $txtDaysOfMonth[1] = $this->natlangApply('elemDOM: on_the_X', $this->natlangApply('ordinal: '.$this->_cronDaysOfMonth['elements'][0]['number1']));
    $txtDaysOfMonth[2] = $this->natlangApply('elemDOM: on_X', $this->natlangRange($this->_cronDaysOfMonth, array($this, 'natlangElementDayOfMonth')));

    $txtMonths = array();
    $txtMonths[0] = $this->natlangApply('elemMonth: of_every_month');
    $txtMonths[1] = $this->natlangApply('elemMonth: during_every_X', $this->natlangApply('month: '.$this->_cronMonths['elements'][0]['number1']));
    $txtMonths[2] = $this->natlangApply('elemMonth: during_X', $this->natlangRange($this->_cronMonths, array($this, 'natlangElementMonth')));

    $classDaysOfMonth = $this->getClass($this->_cronDaysOfMonth);
    $classMonths = $this->getClass($this->_cronMonths);

    if($classDaysOfMonth == '0')
    $switchDaysOfWeekAreExcluding = FALSE;

    switch($classDaysOfMonth.$classMonths)
    {

    // Special case: Unspecified date + Unspecified month
    //
    // Rule: The language for unspecified fields is omitted if a more detailed field has already been explained.
    //
    // The time fields always yield an explaination, at the very least in the form of 'every minute'. This rule states that if the date
    // is not specified, it can be omitted because 'every minute' is already sufficiently clear.
    //
    // There are some time specifications that do not contain an 'every' reference, but reference a specific time of day. In those cases
    // the date explaination is enforced.
    //

    case '00':
    $txtDate = '';
    break;

    default:
    $txtDate = ' '.$txtDaysOfMonth[$classDaysOfMonth].' '.$txtMonths[$classMonths];
    break;
    }


    // Generate Year String

    if ($this->_cronYears) {
    $txtYears = array();
    $txtYears[0] = '';
    $txtYears[1] = ' '.$this->natlangApply('elemYear: in_X', $this->_cronYears['elements'][0]['number1']);
    $txtYears[2] = ' '.$this->natlangApply('elemYear: in_X', $this->natlangRange($this->_cronYears, array($this, 'natlangElementYear')));

    $classYears = $this->getClass($this->_cronYears);
    $txtYear = $txtYears[$classYears];
    }


    // Generate DaysOfWeek String

    $collectDays = 0;
    foreach($this->_cronDaysOfWeek['elements'] as $elem)
    {
    if($elem['hasInterval'])
    for($x = $elem['number1']; $x <= $elem['number2']; $x += $elem['interval'])
    $collectDays |= pow(2, $x);
    else
    $collectDays |= pow(2, $elem['number1']);
    }
    if($collectDays == 127) // * all days
    {
    if(!$switchDaysOfWeekAreExcluding)
    $txtDays = ' '.$this->natlangApply('elemDOM: on_every_day');
    else
    $txtDays = '';
    }
    else
    {
    $arrDays = array();
    for($x = 0; $x <= 6; $x++)
    if($collectDays & pow(2, $x))
    $arrDays[] = $x;
    $txtDays = '';
    for($index = 0; $index < count($arrDays); $index++)
    $txtDays .= ($index == 0 ? '' : ($index == (count($arrDays) - 1) ? ' '.$this->natlangApply($switchDaysOfWeekAreExcluding ? 'separator_or' : 'separator_and').' ' : ', ')).$this->natlangApply('day: '.$arrDays[$index].'_plural');
    if($switchDaysOfWeekAreExcluding) $txtDays = ' '.$this->natlangApply('elemDOW: but_only_on_X', $txtDays);
    else $txtDays = ' '.$this->natlangApply('elemDOW: on_X', $txtDays);
    }

    $txtResult = ucfirst($txtTime).$txtDate.$txtDays;

    if (isset($txtYear)) {
    if ($switchDaysOfWeekAreExcluding) {
    $txtResult = ucfirst($txtTime).$txtDate.$txtYear.$txtDays;
    } else {
    $txtResult = ucfirst($txtTime).$txtDate.$txtDays.$txtYear;
    }
    }

    return $txtResult.'.';
    }
    }