`exception Invalid_char`

This exception is raised when reading an invalid character from a base64 input.

`exception Invalid_table`

This exception is raised if the encoding or decoding table size is not correct.

`type encoding_table = char array`

An encoding table maps integers 0..63 to the corresponding char.

`type decoding_table = int array`

A decoding table maps chars 0..255 to the corresponding 0..63 value or -1 if the char is not accepted.

`val str_encode : ?tbl:encoding_table -> string -> string`

Encode a string into Base64.

`val str_decode : ?tbl:decoding_table -> string -> string`

Decode a string encoded into Base64, raise `Invalid_char` if a character in the input string is not a valid one.

`val encode : ?tbl:encoding_table -> 'a BatIO.output -> 'a BatIO.output`

Generic base64 encoding over an output.

`val decode : ?tbl:decoding_table -> BatIO.input -> BatIO.input`

Generic base64 decoding over an input.

`val make_decoding_table : encoding_table -> decoding_table`

Create a valid decoding table from an encoding one.