my @items = (1,5,6,3,5,2,4);
my $index = -1;

sub add_item
{
  push @items, @_;
}

sub do_next
{
  if (@items)
  {
    $index = ($index+1) % @items;
    do_something($items[$index]);
  }
  else
  {
    $index = -1;
  }
}