base64.h

/*
 * Copyright (C) 2019-2024 Nicola Di Lieto <nicola.dilieto@gmail.com>
 *
 * This file is part of uacme.
 *
 * uacme 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 3 of the License, or
 * (at your option) any later version.
 *
 * uacme 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, see
 * <http://www.gnu.org/licenses/>.
 */

#ifndef base64_H
#define base64_H

#include <stddef.h>

/* Base64 routines adapted from https://www.libsodium.org */

/*
 * ISC License
 *
 * Copyright (c) 2013-2017
 * Frank Denis <j at pureftpd dot org>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

char *bin2hex(char * const hex, const size_t hex_maxlen,
        const unsigned char * const bin, const size_t bin_len)
    __attribute__ ((nonnull(1)));

int hex2bin(unsigned char * const bin, const size_t bin_maxlen,
        const char * const hex, const size_t hex_len,
        const char * const ignore, size_t * const bin_len,
        const char ** const hex_end)
    __attribute__ ((nonnull(1)));

#define base64_VARIANT_ORIGINAL            1
#define base64_VARIANT_ORIGINAL_NO_PADDING 3
#define base64_VARIANT_URLSAFE             5
#define base64_VARIANT_URLSAFE_NO_PADDING  7

/*
 * Computes the required length to encode BIN_LEN bytes as a base64 string
 * using the given variant. The computed length includes a trailing \0.
 */
#define base64_ENCODED_LEN(BIN_LEN, VARIANT) \
    (((BIN_LEN) / 3U) * 4U + \
    ((((BIN_LEN) - ((BIN_LEN) / 3U) * 3U) | (((BIN_LEN) - ((BIN_LEN) / 3U) * 3U) >> 1)) & 1U) * \
     (4U - (~((((VARIANT) & 2U) >> 1) - 1U) & (3U - ((BIN_LEN) - ((BIN_LEN) / 3U) * 3U)))) + 1U)

size_t base64_encoded_len(const size_t bin_len, const int variant);

char *bin2base64(char * const b64, const size_t b64_maxlen,
        const unsigned char * const bin, const size_t bin_len,
        const int variant) __attribute__ ((nonnull(1)));

int base642bin(unsigned char * const bin, const size_t bin_maxlen,
        const char * const b64, const size_t b64_len,
        const char * const ignore, size_t * const bin_len,
        const char ** const b64_end, const int variant)
    __attribute__ ((nonnull(1)));

char *encode_base64url(const char *str);

#endif