Quick sort in PHP

gistfile1.php

<?php
function partition(Array &$array, $left, $right, $pivot)
{
    $il = $left;
    $ir = $right - 1;

    while ($il < $ir) {
        while ($il < $right && $array[$il] <= $pivot) $il++;
        while ($ir >= $left && $array[$ir] > $pivot) $ir--;
        if ($il >= $ir) break;
        list($array[$il], $array[$ir]) = array($array[$ir], $array[$il]);
    }
    return $ir + 1;
}

function quicksort(Array &$array)
{
    _quicksort($array, 0, count($array));
}

function _quicksort(&$array, $left, $right)
{
    if ($right - $left <= 1) return;

    $pivotIdx = findPivotIdx($array, $left, $right);
    if ($pivotIdx < 0) return;

    $mid = partition($array, $left, $right, $array[$pivotIdx]);
    _quicksort($array, $left, $mid);
    _quicksort($array, $mid, $right);
}

function findPivotIdx($array, $left, $right)
{
    if ($right - $left <= 1) return -1;
    $t = $array[$left];
    for ($i = $left + 1; $i < $right; $i++) {
        if ($array[$i] === $t) continue;
        if ($array[$i] < $t) return $i;
        return $left;
    }
    return -1;
}

$ar = array(7,2,1,6,8,4);
quicksort($ar);
var_dump($ar);
/*
array(6) {
  [0]=>
  int(1)
  [1]=>
  int(2)
  [2]=>
  int(4)
  [3]=>
  int(6)
  [4]=>
  int(7)
  [5]=>
  int(8)
}
*/