My goal here was just to check the influence of pre-bound variables, a-la bind_columns () in DBI and Text::CSV_XS. It wouldn't be too hard to rewrite the init routine to pass it any for of references and make uicb () (Unpack Inline C Bind), store the results in exactly the variables you want and thus bypass all the unwanted copying and the mortalizing cost.

The fact that you are dealing with a very limited range makes this very feasible.