(*

 * 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 maps chars 0..255 to the corresponding 0..63 value

 or -1 if the char is not accepted. *)

type decoding_table = int array

(** erroneous interface, kept for compatibility use [encode_string] instead *)

val str_encode : ?tbl:encoding_table -> string -> Bytes.t

(** erroneous interface, kept for compatibility use [decode_string] instead *)

val str_decode : ?tbl:decoding_table -> Bytes.t -> string

(** Encode a string into Base64. *)

val encode_string : ?tbl:encoding_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 decode_string : ?tbl:decoding_table -> string -> 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