/**
* A multi-key sort
* 1. First divide the facts into two arrays one set with dates and one set without dates
* 2. Sort each of the two new arrays, the date using the compare date function, the non-dated
* using the compare type function
* 3. Then merge the arrays back into the original array using the compare type function
*
* @param WT_Fact[] $arr
*/
function sort_facts(&$arr)
{
$dated = array();
$nondated = array();
//-- split the array into dated and non-dated arrays
$order = 0;
foreach ($arr as $event) {
$event->sortOrder = $order;
$order++;
if ($event->getDate()->isOk()) {
$dated[] = $event;
} else {
$nondated[] = $event;
}
}
//-- sort each type of array
usort($dated, array("WT_Fact", "CompareDate"));
usort($nondated, array("WT_Fact", "CompareType"));
//-- merge the arrays back together comparing by Facts
$dc = count($dated);
$nc = count($nondated);
$i = 0;
$j = 0;
$k = 0;
// while there is anything in the dated array continue merging
while ($i < $dc) {
// compare each fact by type to merge them in order
if ($j < $nc && WT_Fact::CompareType($dated[$i], $nondated[$j]) > 0) {
$arr[$k] = $nondated[$j];
$j++;
} else {
$arr[$k] = $dated[$i];
$i++;
}
$k++;
}
// get anything that might be left in the nondated array
while ($j < $nc) {
$arr[$k] = $nondated[$j];
$j++;
$k++;
}
}
