let big_int_of_number base offset s =
let length = String.length s in
let rec continue n i =
if i >= length then
zero_big_int
else
let n = mult_int_big_int base n in
let n = add_int_big_int (int_of_16_char s.[i]) n in
if i = length - 1 then
n
else
continue n (i + 1)
in
continue zero_big_int offset