(*
 * Base64 - Base64 codec
 * Copyright (C) 2003 Nicolas Cannasse
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version,
 * with the special exception on linking described in file LICENSE.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *)

(** Base64 codec.

  8-bit characters are encoded into 6-bit ones using ASCII lookup tables.
  Default tables maps 0..63 values on characters A-Z, a-z, 0-9, '+' and '/'
  (in that order). 
*)

open ExtBytes

(** This exception is raised when reading an invalid character
  from a base64 input. *)
exception Invalid_char

(** This exception is raised if the encoding or decoding table
  size is not correct. *)
exception Invalid_table

(** An encoding table maps integers 0..63 to the corresponding char. *)
type encoding_table = char array

(** A decoding table mais chars 0..255 to the corresponding 0..63 value
 or -1 if the char is not accepted. *)
type decoding_table = int array

(** Encode a string into Base64. *)
val str_encode : ?tbl:encoding_table -> string -> Bytes.t

(** Decode a string encoded into Base64, raise [Invalid_char] if a
  character in the input string is not a valid one. *)
val str_decode : ?tbl:decoding_table -> Bytes.t -> string

(** Generic base64 encoding over an output. *)
val encode : ?tbl:encoding_table -> 'a IO.output -> 'a IO.output

(** Generic base64 decoding over an input. *)
val decode : ?tbl:decoding_table -> IO.input -> IO.input

(** Create a valid decoding table from an encoding one. *)
val make_decoding_table : encoding_table -> decoding_table
