Max subarray using Kadane's algorithm

<?php
/**
 * Using Kadane's algorithm
 * premshree, 07/17/10
 */
function find_max_subarray($arr) {
   //start and end are the indices that we'll eventually return
   $start = 0;
   $end = 0;
   $sum = 0;

   // tstart and tend keep track of temp runs; tsum keeps track of
   //  the sum of the temp run
   $tstart = 0;
   $tend = 0;
   $tsum = 0;
   $curr_pos = 0;

   foreach ($arr as $ele) {
      // temp run
      if ($tsum+$ele<=0) {
         $tsum = 0;
         $tstart = $curr_pos+1;
      } else {
         $tsum += $ele;
         $tend = $curr_pos;
      }

      // change indices based on temp run
      if ($tsum > $sum) {
         $sum = $tsum;
         $start = $tstart;
         $end = $tend;
      }
      $curr_pos++;
   }

   for ($i=$start; $i<=$end; $i++) {
      $ret[] = $arr[$i];
   }
   return $ret;
}

var_dump (
   find_max_subarray(
      array(0, 2, 4, -6, 6, 7, 9, -1, 1, -7)
   )
);
?>