-module(niftest).
-on_load(init/0).

-export([
  init/0,
  hello/0,
  factorial/1
]).

-nifs([
  hello/0,
  factorial1/1
]).


init() ->
  erlang:load_nif("./niftest", 0).


hello() ->
  erlang:nif_error("NIF library not loaded").


factorial(N) when is_integer(N), N >= 0 ->
  case factorial1(N) of
    Bin when is_binary(Bin) ->
      binary:decode_unsigned(Bin);
    Error ->
      Error
  end;

factorial(_) ->
  {error, badarg}.


factorial1(_) ->
  "NIF not loaded".