$this->sections = array();

  /**

   * \brief

   *   Retrieve a section of this class based on its letter.

   *

   * \todo Make this function replace completely the getSection()

   * function, have $this->sections be keyed by letter, and have a

   * __wakup() convert the old $this->sections format to the new one.

   *

   * \return

   *   The requested section or NULL if that section does not yet

   *   exist for this class.

   */

  public function section_get($letter)

  {

    foreach ($this->sections as $section)

      if ($section->getLetter() == $letter)

	return $section;

    return NULL;

  }

	$section_json_arrays = $section->to_json_arrays();

	foreach ($section_json_arrays as $section_json_array)

	  $json_array['sections'][] = $section_json_array;

  function addSection($course_name, $letter, $time_start, $time_end, $days, $synonym = NULL, $faculty = NULL, $room = NULL)

	if((strcmp($temp,$course_name)) == 0)

	echo 'Could not find class: ' . $course_name . "<br />\n";

      $section = $this->classStorage[$counter]->section_get($letter);

      if (!$section)

	{

	  $section = new Section($letter, array(), $synonym, $faculty);

	  $this->classStorage[$counter]->section_add($section);

	}

      $section->meeting_add(new SectionMeeting($days, $time_start, $time_end, $room));

		  $last_meeting = NULL;

			  $class = $this->classStorage[$j];

			  $section_index = $this->storage[$i][$j];

			  $section = $class->getSection($section_index);

				  /* iterate through all of a class's meeting times */

				  $meetings = $section->getMeetings();

				  /* find any meeting which are going on at this time */

				  $current_meeting = NULL;

				  foreach ($meetings as $meeting)

				    {

				      if ($meeting->getDay($dayLoop)

					  && $meeting->getStartTime() >= $time[$r]

					  && $meeting->getStartTime() < $time[$r+1])

					{

					  $current_meeting = $meeting;

					  /* $last_meeting has meaning for a longer time than $current_meeting does. */

					  $last_meeting = $meeting;

					}

				    }

				  if ($current_meeting)

				    {

				      // Checks if the class continues after the given time

				      if($current_meeting->getEndTime() > $time[$r+1])

					  $table .= "\n\t\t<td class=\"top class{$j}\">" . htmlentities($class->getName()) . " " . htmlentities($section->getLetter()) . "</td>";

					  $this->setClassCont($dayLoop, $j);

					  $filled = TRUE;

					}

				      else

					{

					  $table .= "\n\n\t<td class=\"single class{$j}\">" . htmlentities($class->getName()) . " " . htmlentities($section->getLetter()) . "</td>";

					  $filled = TRUE;

				    }

				else

				  {

				    if($j == $this->getClassCont($dayLoop))

				      {

					if($last_meeting

					   && $last_meeting->getEndTime() > $time[$r+1])

					  {

					    $table .= "\n\t\t<td class=\"mid class{$j}\">&nbsp;</td>";

					    $filled = TRUE;

					  }

					else

					  {

					    $table .= "\n\t\t<td class=\"end class{$j}\">&nbsp;</td>";

					    $this->setClassCont($dayLoop, -1);

					    $filled = TRUE;

					  }

				      }

			  }

		}

require_once('inc/class.section_meeting.inc');

  /* meeting times, array of SectionMeeting */

  private $meetings;

  /* the section synonym which uniquely identifies this section/course combination */

  private $synonym;

   * \param $section_meetings

   *   An array of SectionMeeting objects which describe all the

   *   different types of meetings this particular section has. It

   *   will be very uncommon for a course to have more than one such

   *   meeting time for a section. For example, Calvin doesn't have

   *   this. Another example, Cedarville lists different meeting times

   *   inside of a single section. Cedarville also lists all lectures

   *   and lab meeting times directly in a section's listing.

   * \param $synonym

   *   Some schools have a unique number for each section. This field

   *   is for that number.

  function __construct ($letter, array $section_meetings = array(), $synonym = NULL, $prof = NULL)

    $this->meetings = $section_meetings;

    $this->prof = $prof;

  /**

   * \brief

   *   Get an array of section meetings for this section.

   *

   * \return

   *   An array of SectionMeeting objects.

   */

  public function getMeetings()

    return $this->meetings;

   *   Check if this section conflicts with the given section.

    foreach ($this->meetings as $this_meeting)

      foreach ($that->meetings as $that_meeting)

      if ($this_meeting->conflictsWith($that_meeting))

	return TRUE;

    return FALSE;

  }

  /**

   * \brief

   *   Add another section meeting time to this section.

   *

   * Useful for process.php when it's calling

   * Schedule::addSectionMeeting() multiple times.

   */

  public function meeting_add(SectionMeeting $meeting)

  {

    $this->meetings[] = $meeting;

   *   Get arrays of information needed by the AJAX stuff.

   *

   * \return

   *   An array of arrays that should be merged with the return value

   *   of other Section::to_json_array() calls.

  public function to_json_arrays()

    $json_arrays = array();

    foreach ($this->meetings as $meeting)

      {

	$json_array = array('section' => $this->letter,

			    'prof' => $this->prof,

			    'synonym' => $this->synonym,

			    );

	$json_array += $meeting->to_json_array();

	$json_arrays[] = $json_array;

      }

    return $json_arrays;

  }

  /* for legacy unserialization */

  private $start;

  private $tend;

  private $bdays;

  /**

   * \brief

   *   A magic function which tries to upgrade old serialized sections

   *   to the new format.

   */

  public function __wakeup()

  {

    /* upgrade to SectionMeeting stuffage */

    if (!empty($this->start))

      {

	$days = '';

	$daymap = array(0 => 'm', 1 => 't', 2 => 'w', 3 => 'h', 4 => 'f');

	foreach ($this->bdays as $day => $have_day)

	  if ($have_day)

	    $days .= $daymap[$day];

	$this->meetings = array();

	$this->meeting_add(new SectionMeeting($days, $this->start, $this->tend, '<location unknown>', 'lecture'));

	/*

	 * if we're reserialized in the future, make sure we don't do this same upgrade procedure again ;-).

	 */

	unset($this->start);

      }

<?php

/**

 * \brief

 *   Represent a time/location that a Section meets during/at.

 *

 * A Calvin student might ask ``Why is there a need for a

 * SectionMeeting class? Doesn't every Section have a unique

 * prof/time/location?'' A Cedarville student would retort ``Huh?

 * Don't some of your classes have labs in addition to lecture? How do

 * you know that you have to go to both a lecture and lab -- and how

 * do you handle that some classes have different lecture times for

 * different days of the week?''. A Calvin section _is_ a unique

 * prof/time/location. At Cedarville, a Section refers to a prof and a

 * _set_ of time/location pairs. The generalization is to make each

 * Section support a list of meeting times/locations.

 */

class SectionMeeting

{

  private $time_start;

  private $time_end;

  private $days;

  private $location;

  /**

   * \brief

   *   Construct a SectionMeeting.

   *

   * \param $days

   *   A string of single-char day upon which a section meets. Monday

   *   is represented with 'm', Tuesday with 't', Wednesday with 'w',

   *   Thursday with 'h', and Friday with 'f'.

   * \param $time_start

   *   The time of day when the section meeting starts.

   * \param $time_end

   *   The time of day when the section meeting ends.

   * \param $location

   *   Where the meeting occurs. Often a room number of some sort.

   * \param $type

   *   The type of meeting this is. For lectures, please use

   *   'lecture'. For labs, please use 'lab'. For others, use the

   *   school's notation.

   */

  public function __construct($days, $time_start, $time_end, $location = NULL, $type = 'lecture')

  {

    $this->days_set($days);

    $this->time_start = $time_start;

    $this->time_end = $time_end;

    $this->location = $location;

    $this->type = $type;

  }

  /**

   * \brief

   *   Take a days of week string and store it into our $days of week array.

   *

   * \param $days_str

   *   The days of the week in a string format. One char per

   *   day. Mon-Fri is represented with 'm', 't', 'w', 'h', 'f'.

   */

  private function days_set($days_str)

  {

    $this->days = array(0 => FALSE, 1 => FALSE, 2 => FALSE, 3 => FALSE, 4 => FALSE);

    $days_str_strlen = strlen($days_str);

    for ($i = 0; $i < $days_str_strlen; $i ++)

      $this->days[self::day_atoi($days_str[$i])] = TRUE;

  }

  /**

   * \brief

   *   Convert a day letter to a day numeral.

   *

   * Works fine if you give the numeral as well.

   */

  private static function day_atoi($day_c)

  {

    static $day_atoi = array('m' => 0, 't' => 1, 'w' => 2, 'h' => 3, 'f' => 4,

			     'M' => 0, 'T' => 1, 'W' => 2, 'H' => 3, 'F' => 4,

			       0 => 0,   1 => 1,   2 => 2,   3 => 3,   4 => 4);

    return $day_atoi[$day_c];

  }

  /**

   * \brief

   *   Determine whether or not this class meeting time meets on a

   *   specified day of the week or not.

   *

   * \param $day

   *   The letter or numeral of the day to retrieve.

   * \return

   *   TRUE if this section meeting meets on that day. FALSE

   *   otherwise.

   */

  public function getDay($day)

  {

    return $this->days[self::day_atoi($day)];

  }

  /**

   * \return

   *   This SectionMeeting's location or NULL if none is defined.

   */

  public function getLocation()

  {

    return $this->location;

  }

  /**

   * \brief

   *   Get the start_time of this meeting in slate_permutate's internal format.

   */

  public function getStartTime()

  {

    return $this->time_start;

  }

  public function getEndTime()

  {

    return $this->time_end;

  }

  /**

   * \brief

   *   Check if this section conflicts with the given section.

   *

   * \param $that

   *   The other section for which I should check for conflicts.

   * \return

   *   TRUE if there is a conflict, FALSE otherwise.

   */

  public function conflictsWith(SectionMeeting $that)

  {

    /*

     * The two sections meetings can't conflict if the start/end times

     * don't overlap. Also, use >= or <= here so that one can say ``I

     * have gym from 10 through 11 and then latin from 11 though 12''.

     */	

    if ($this->getStartTime() >= $that->getEndTime()

	|| $this->getEndTime() <= $that->getStartTime())

      {

	return FALSE;

      }

    /*

     * Now we know that the sections meetings overlap in start/end

     * times. But if they don't both meet on the same day at least

     * once, they don't conflict.

     */

    for ($day = 0; $day < 5; $day ++)

      {

	if ($this->getDay($day) && $that->getDay($day))

	  return TRUE;

      }

    /*

     * The sections meetings don't both share a day of the week.

     */

    return FALSE;

  }

  /**

   * \brief

   *   Return an array of JSON keys specific to this section meeting

   *   time.

   *

   * Currently, the AJAX UI doesn't recognize that a given section may

   * have multiple meeting times. Thus, we simulate this by having

   * multiple instances of the same section but just with different

   * times in the UI.

   */

  public function to_json_array()

  {

    static $daymap = array(0 => 'm', 1 => 't', 2 => 'w', 3 => 'h', 4 => 'f');

    $json_array = array(

			'time_start' => $this->time_start,

			'time_end' => $this->time_end,

			'days' => array(),

			'location' => $this->location,

			);

    for ($day = 0; $day < 5; $day ++)

      $json_array['days'][$daymap[$day]] = $this->getDay($day);

    return $json_array;

  }

}