/**
 * @copyright
 *
 * Tencent is pleased to support the open source community by making IoT Hub available.
 * Copyright(C) 2018 - 2021 THL A29 Limited, a Tencent company.All rights reserved.
 *
 * Licensed under the MIT License(the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://opensource.org/licenses/MIT
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is
 * distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * @file utils_base64.h
 * @brief utils base64 header file
 * @author fancyxu (fancyxu@tencent.com)
 * @version 1.0
 * @date 2021-05-28
 *
 * @par Change Log:
 * <table>
 * <tr><th>Date       <th>Version <th>Author    <th>Description
 * <tr><td>2021-05-28 <td>1.0     <td>fancyxu   <td>first commit
 * </table>
 */

#ifndef IOT_HUB_DEVICE_C_SDK_COMMON_CRYPTOLOGY_INC_UTILS_BASE64_H_
#define IOT_HUB_DEVICE_C_SDK_COMMON_CRYPTOLOGY_INC_UTILS_BASE64_H_

#ifdef __cplusplus
extern "C" {
#endif

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>

/**
 * @brief Encode a buffer into base64 format.
 *
 * @param[out] dst destination buffer
 * @param[in] dlen size of the destination buffer
 * @param[out] olen number of bytes written
 * @param[in] src source buffer
 * @param[in] slen amount of data to be encoded
 * @return 0 if successful, or MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL.
 *         *olen is always updated to reflect the amount
 *         of data that has (or would have) been written.
 *         If that length cannot be represented, then no data is
 *         written to the buffer and *olen is set to the maximum
 *         length representable as a size_t.
 *
 * @note Call this function with dlen = 0 to obtain the
 *       required buffer size in *olen
 */
int utils_base64encode(unsigned char *dst, size_t dlen, size_t *olen, const unsigned char *src, size_t slen);

/**
 * @brief Decode a base64-formatted buffer.
 *
 * @param[out] dst destination buffer (can be NULL for checking size)
 * @param[in] dlen size of the destination buffer
 * @param[out] olen number of bytes written
 * @param[in] src source buffer
 * @param[in] slen amount of data to be decoded
 * @return 0 if successful, MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL, or
 *         MBEDTLS_ERR_BASE64_INVALID_CHARACTER if the input data is
 *         not correct. *olen is always updated to reflect the amount
 *         of data that has (or would have) been written.
 *
 * @note Call this function with *dst = NULL or dlen = 0 to obtain
 *       the required buffer size in *olen
 */
int utils_base64decode(unsigned char *dst, size_t dlen, size_t *olen, const unsigned char *src, size_t slen);

#ifdef __cplusplus
}
#endif

#endif  // IOT_HUB_DEVICE_C_SDK_COMMON_CRYPTOLOGY_INC_UTILS_BASE64_H_