#pragma once

/*

 *   This program is free software; you can redistribute it and/or modify

 *   it under the terms of the GNU General Public License as published by

 *   the Free Software Foundation; either version 2 of the License, or

 *   (at your option) any later version.

 *

 *   This program 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 General Public License for more details.

 *

 *   You should have received a copy of the GNU General Public License

 *   along with this program; if not, write to the Free Software

 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA

 */

/** Encode/decode binary data using printable characters (base64 format)

 *

 * @see RFC 4648 <http://www.ietf.org/rfc/rfc4648.txt>.

 *

 * @copyright 2021 Arran Cudbard-Bell (a.cudbardb@freeradius.org)

 */

RCSIDH(base64_h, "$Id: 9e913b39feb72bfd4eb57c67f0f852918acaf691 $")

#ifdef __cplusplus

extern "C" {

#endif

#include <freeradius-devel/missing.h>

#include <freeradius-devel/util/sbuff.h>

#include <freeradius-devel/util/dbuff.h>

#include <sys/types.h>

/*

 *  This uses that the expression (n+(k-1))/k means the smallest

 *  Integer >= n/k, i.e., the ceiling of n/k.

 */

#define FR_BASE64_ENC_LENGTH(_inlen) ((((_inlen) + 2) / 3) * 4)

#define FR_BASE64_DEC_LENGTH(_inlen) ((3 * ((_inlen) / 4)) + 2)

extern char const fr_base64_alphabet_encode[SBUFF_CHAR_CLASS];

extern uint8_t const fr_base64_alphabet_decode[SBUFF_CHAR_CLASS];

extern char const fr_base64_url_alphabet_encode[SBUFF_CHAR_CLASS];

extern uint8_t const fr_base64_url_alphabet_decode[SBUFF_CHAR_CLASS];

/** Check if char is in Base64 alphabet

 *

 * Note that '=' is padding and not considered to be part of the alphabet.

 *

 * @param[in] c   char to check.

 * @param[in] alphabet  to use.

 * @return

 *  - true if c is a character from the Base64 alphabet.

 *  - false if character is not in the Base64 alphabet.

 */

static inline bool fr_is_base64_nstd(char c, uint8_t const alphabet[static SBUFF_CHAR_CLASS])

{

  return alphabet[(uint8_t)c] < 64;

}

size_t    fr_base64_encode(char * restrict out, size_t outlen, uint8_t const * restrict in, size_t inlen);

#define   fr_is_base64(_c) fr_is_base64_nstd(_c, fr_base64_alphabet_decode)

ssize_t   fr_base64_encode_nstd(fr_sbuff_t *out, fr_dbuff_t *in,

                    bool add_padding, char const alphabet[static SBUFF_CHAR_CLASS])

                    CC_HINT(nonnull);

#define   fr_base64_encode(_out, _in, _add_padding) \

    fr_base64_encode_nstd(_out, _in, _add_padding, fr_base64_alphabet_encode)

ssize_t   fr_base64_decode_nstd(fr_sbuff_parse_error_t *err, fr_dbuff_t *out, fr_sbuff_t *in,

              bool expect_padding, bool no_trailing, uint8_t const alphabet[static SBUFF_CHAR_CLASS])

              CC_HINT(nonnull(2,3,6));

#define   fr_base64_decode(_out, _in, _expect_padding, _no_trailing) \

    fr_base64_decode_nstd(NULL, _out,  _in, _expect_padding, _no_trailing, fr_base64_alphabet_decode)

#ifdef __cplusplus

}

#endif