module Base64: sig end
8-bit characters are encoded into 6-bit ones using ASCII characters A-Z,
a-z, 0-9, and '+' , '/' (in that order).
exception Invalid_char
val str_encode : string -> string
val str_decode : string -> string
Invalid_char
if a
character in the input string is not a valid one.val encode : (char, 'a, 'b) IO.output -> (char, string, 'b) IO.output
val decode : (char, 'a) IO.input -> (char, string) IO.input