how would I detect a non-overlap of two time periods? - php

Question

I have a user input form where user select the date in (YYYY-mm-dd) format, and start time in (H:i) and end time in (H:i) format, or assume i have three variable with following values.
$date = '2012-11-22';
$startTime = '1:00';
$endTime = '4:00';
i now have to compare this values with existing array of values. my existing array look like this.
Array
(
[0] => Array
(
[id] => 1
[start_datetime] => 2012-11-22 02:30:00
[end_datetime] => 2012-11-22 05:00:00
)
[1] => Array
(
[id] => 2
[start_datetime] => 2012-11-22 00:00:00
[end_datetime] => 2012-11-22 02:30:00
)
[2] => Array
(
[id] => 3
[start_datetime] => 2012-11-22 05:00:00
[end_datetime] => 2012-11-22 08:00:00
)
[3] => Array
(
[id] => 4
[start_datetime] => 2012-11-22 08:00:00
[end_datetime] => 2012-11-22 11:00:00
)
[4] => Array
(
[id] => 5
[start_datetime] => 2012-11-22 11:00:00
[end_datetime] => 2012-11-22 17:00:00
)
)
i have to check if the user input selected [date, startTime, and endTime] has any of the slots already booked in the given array of time slots. from what i see the solution is to first split and match the date, if it matches the date then time needs to be matched accordingly. i am confused about how to go with it. i hope to get some simple solution from you guys :)
thank you.
UPDATE:
i tried doing this way.
$arenaSurfaceBooking = array(
array(
'id' => 1,
'start_datetime' => '2012-11-22 02:30:00',
'end_datetime' => '2012-11-22 05:00:00',
),
array(
'id' => 2,
'start_datetime' => '2012-11-22 00:00:00',
'end_datetime' => '2012-11-22 02:30:00',
),
array(
'id' => 3,
'start_datetime' => '2012-11-22 05:00:00',
'end_datetime' => '2012-11-22 08:00:00',
),
array(
'id' => 4,
'start_datetime' => '2012-11-22 08:00:00',
'end_datetime' => '2012-11-22 11:00:00',
),
array(
'id' => 5,
'start_datetime' => '2012-11-22 11:00:00',
'end_datetime' => '2012-11-22 17:00:00',
)
);
foreach($arenaSurfaceBooking as $booking) {
$bookedDateTimestamp = strtotime(date('Y-m-d', strtotime($booking['start_datetime'])));
$inputDateTimestamp = strtotime($context['date']);
$bookedStartTime = strtotime(date('H:i', strtotime($booking['start_datetime'])));
$bookedEndTime = strtotime(date('H:i', strtotime($booking['end_datetime'])));
$userStartTime = strtotime(date('H:i', strtotime($context['start_datetime'])));
$userEndTime = strtotime(date('H:i', strtotime($context['end_datetime'])));
if( $bookedDateTimestamp == $inputDateTimestamp) {
if( $userEndTime <= $bookedStartTime || $userStartTime >= $bookedEndTime) {
echo 'i am booked';
}
}
}
it's not working.

Answer 1

Let's assume the user date/time is formatted like so:
$date = '2012-11-22';
$startTime = '01:00'; // note the extra '0' in front
$endTime = '04:00';
$userStartTime = "$date $startTime";
$userEndTime = "$date $endTime";
Finding overlaps is done this way:
$overlaps = 0;
foreach ($block as $block) {
if ($userStartTime < $block['end_datetime'] && $userEndTime > $block['start_datetime']) {
++$overlaps;
}
}
// if $overlaps > 0 -> there's a booking in the way
This is basically taking a non-overlap condition like this:
$userEndTime <= $block['start_datetime'] || $userStartTime >= $block['end_datetime']
And simply swap the conditions.
This can easily be written into SQL as well to reduce the network overhead between database and application.

Answer 2

Check this out... and modify it according to your requirement to match all existing time... I've matched only one for you...
$date = '2012-11-22';
$startTime = '2:30';
$endTime = '4:00';
$existing[] =
array
(
'id' => 1,
'start_datetime' => '2012-11-22 02:30:00',
'end_datetime' => '2012-11-22 05:00:00'
);
$UserStartTime = strtotime($date." ".$startTime);
$UserEndTime = strtotime($date." ".$endTime);
$ExistingStartTime = strtotime($existing[0]['start_datetime']);
$ExistingEndTime = strtotime($existing[0]['end_datetime']);
if($UserStartTime >= $ExistingStartTime && $UserEndTime <= $ExistingEndTime)
{
echo "BOOKED";
}
else
{
echo "NOT BOOKED";
}

Answer 3

Since the existing array comes from a SQL query:
$date = '2012-11-22';
$startTime = '1:00';
$endTime = '4:00';
if(strlen($startTime==4)){$startTime="0".$startTime;}
if(strlen($endTime==4)){$endTime="0".$startTime;}
$query="SELECT id FROM table WHERE start_datetime='$date $startTime:00' OR end_datetime='$date $endtimeTime:00'";
If the query returns something, the id returned have it booked!
If you want to know if any of the db info matches both datetimes just replace the OR with a AND.
If you want to know if the user time period is between any of the entries of the DB:
$query="SELECT id FROM table WHERE (start_datetime>='$date $startTime:00' AND start_datetime<='$date $endTime:00') OR (end_datetime<='$date $starttimeTime:00' AND end_datetime>='$date $endtimeTime:00') OR (start_datetime<='$date $startTime:00' AND end_datetime>='$date $starttimeTime:00')";

Answer 4

This may help you
$date = '2012-11-22';
$startTime= '1:00:00'; // padded two zero
$endTime = '4:00:00'; // padded two zero
$start_datetime = $date. " ".(strlen(intval(substr($startTime,0,2))) > 1 ? $startTime : "0".$startTime);
$end_datetime = $date. " ".(strlen(intval(substr($endTime,0,2))) > 1? $endTime : "0".$endTime);
for($i = 0;$i<count($your_array);$i++)
{
if($your_array[$i]['start_datetime'] == $start_datetime)
{
// Start date Found
}
if($your_array[$i]['end_datetime'] == $end_datetime)
{
// Start end Found
}
}