Split a string to an array by an array of positions

<?php
/**
 * Split a string to an array by an array of positions.
 * @param
 * @return
$pos = array(0, 1, 3, 6, 10);
$str = "abbcccddddeeeee";
$arr = split_str_by_pos($str, $pos);
*/
function split_str_by_pos($str, $pos) {
  $arr = array();

  $count = count($pos);
  $leng = strlen($str);

  for ($i=0;$i<$count;$i++) {
    $start = $pos[$i];
    $end = ($i == $count - 1) ? $leng : $pos[$i+1];

    $fieldVal = '';

    for ($j = $start; $j < $end; $j++) {
      $fieldVal .= $str[$j];
    }

    $arr[] = $fieldVal;
  }

  return $arr;
}
?>