';
# process the form input
if ($form['submitted']) {
# wrong input
if (!isset($table[$form['date']][$form['time']][$form['computer']])) {
$error_message = '
Invalid time slot. Please correct it and submit again.
That time slot is already taken. Please choose another one.
';
}
# everything's okay, let's add this to the table
else {
add_to_table($form['date'], $form['time'], $form['computer'], $form['name']);
# reload this page, to avoid re-submitting the form when clicking F5
header("Location: .");
exit;
}
}
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
?>
CS4706 - Sign-up page for the Linux computers in the Speech Lab
CS4706 - Sign-up page for the Linux computers in the Speech Lab
Instructions
To reserve a computer, select the date, time and computer
of an empty slot, enter your name, and hit the SUBMIT button.
Make a reservation only if you are sure that you will use it.
WARNING: Reservations cannot be canceled
using this page. Please be careful! If you need to cancel a reservation, send an e-mail to Fadi with
the exact subject "CS4706 - Cancel reservation".
Do not wait until the last minute to do this assignment. There will probably
be shortage of time slots on the days previous to the due date.
Check out in the lab page
who the lab monitor is on the day/time you come in, and talk to him for assistance.
Please report bugs in this webpage by e-mail to Fadi.
>
Date
Time
.cs
0) {
# append $MY_NUMBER to the lock file
$fh = fopen(LOCKFILE, 'a');
fwrite($fh, $MY_NUMBER."\n");
fclose($fh);
# now read the lock file
$lines = file(LOCKFILE);
$first_number = rtrim($lines[0]);
# it's our turn, succeeded!
if ($MY_NUMBER == $first_number) return;
# otherwise, let's wait 0.5 seconds and retry.
usleep(500000);
print $first_number;
# decrease the number of attempts
$attempts--;
}
# write (not append) $MY_NUMBER to the lock file
$fh = fopen(LOCKFILE, 'w');
fwrite($fh, $MY_NUMBER."\n");
fclose($fh);
}
# unlocks the table
function unlock_table() {
# empties the lock file.
$fh = fopen(LOCKFILE, 'w');
fwrite($fh, "");
fclose($fh);
}
# initializes the table with '' in all cells
function initialize_table(&$table) {
global $DATES, $TIMES, $COMPUTERS;
foreach ($DATES as $date) {
foreach ($TIMES as $time) {
foreach ($COMPUTERS as $computer) {
$table[$date][$time][$computer] = '';
}
}
}
}
# says whether $date should be shown or not
function show_this_date($date) {
global $show_all;
if ($show_all) return TRUE;
# only show dates between now and N weeks in the future.
if (strtotime("23:59 $date") < time()) return FALSE;
if (strtotime("00:00 $date") > time()+60*60*24*7*N_WEEKS) return FALSE;
return TRUE;
}
?>