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RIOT/sys/include/base64.h
Marian Buschsieweke 3c7fd0cdc9
sys/base64: Use void pointer for buffers in API
This is a non-breaking change, as `unsigned char *` can implicitly be converted
to `void *`.
2020-07-02 11:10:06 +02:00

132 lines
5.9 KiB
C

/*
* Copyright (C) 2014 Hochschule für Angewandte Wissenschaften Hamburg (HAW)
* Copyright (C) 2014 Martin Landsmann <Martin.Landsmann@HAW-Hamburg.de>
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @defgroup sys_base64 base64 encoder decoder
* @ingroup sys_serialization
* @brief base64 encoder and decoder
* @{
*
* @brief encoding and decoding functions for base64
* @author Martin Landsmann <Martin.Landsmann@HAW-Hamburg.de>
*/
#ifndef BASE64_H
#define BASE64_H
#include <stddef.h> /* for size_t */
#ifdef __cplusplus
extern "C" {
#endif
#define BASE64_SUCCESS (0) /**< return value for success */
#define BASE64_ERROR_BUFFER_OUT (-1) /**< error value for invalid output buffer pointer */
#define BASE64_ERROR_BUFFER_OUT_SIZE (-2) /**< error value for invalid output buffer size */
#define BASE64_ERROR_DATA_IN (-3) /**< error value for invalid input buffer */
#define BASE64_ERROR_DATA_IN_SIZE (-4) /**< error value for invalid input buffer size */
/**
* @brief Estimates the amount of bytes needed for decoding @p base64_in_size
* characters from base64.
*
* @param[in] base64_in_size Size of the string to be decoded
* @return Amount of bytes estimated to be used after decoding
*/
static inline size_t base64_estimate_decode_size(size_t base64_in_size)
{
return (((base64_in_size + 3) / 4) * 3);
}
/**
* @brief Estimates the length of the resulting string after encoding
* @p data_in_size bytes into base64.
*
* @param[in] data_in_size Amount of bytes to be encoded
* @return Amount of characters the output string is estimated to have
*/
static inline size_t base64_estimate_encode_size(size_t data_in_size)
{
return (4 * ((data_in_size + 2) / 3));
}
/**
* @brief Encodes a given datum to base64 and save the result to the given destination.
* @param[in] data_in pointer to the datum to encode
* @param[in] data_in_size the size of `data_in`
* @param[out] base64_out pointer to store the encoded base64 string
* @param[in,out] base64_out_size pointer to the variable containing the size of `base64_out.`
This value is overwritten with the estimated size used for
the encoded base64 string on BASE64_ERROR_BUFFER_OUT_SIZE.
This value is overwritten with the actual used size for the
encoded base64 string on BASE64_SUCCESS.
* @returns BASE64_SUCCESS on success,
BASE64_ERROR_BUFFER_OUT_SIZE on insufficient size for encoding to `base64_out`,
BASE64_ERROR_BUFFER_OUT if `base64_out` equals NULL
but the `base64_out_size` is sufficient,
BASE64_ERROR_DATA_IN if `data_in` equals NULL.
*/
int base64_encode(const void *data_in, size_t data_in_size,
void *base64_out, size_t *base64_out_size);
/**
* @brief Encodes a given datum to base64 with URL and Filename Safe Alphabet
* and save the result to the given destination.
*
* @see [RFC 4648, section 5](https://tools.ietf.org/html/rfc4648#section-5)
*
* @note Requires the use of the `base64url` module.
*
* @param[in] data_in pointer to the datum to encode
* @param[in] data_in_size the size of `data_in`
* @param[out] base64_out pointer to store the encoded base64 string
* @param[in,out] base64_out_size pointer to the variable containing the size of `base64_out.`
This value is overwritten with the estimated size used for
the encoded base64 string on BASE64_ERROR_BUFFER_OUT_SIZE.
This value is overwritten with the actual used size for the
encoded base64 string on BASE64_SUCCESS.
* @returns BASE64_SUCCESS on success,
BASE64_ERROR_BUFFER_OUT_SIZE on insufficient size for encoding to `base64_out`,
BASE64_ERROR_BUFFER_OUT if `base64_out` equals NULL
but the `base64_out_size` is sufficient,
BASE64_ERROR_DATA_IN if `data_in` equals NULL.
*/
int base64url_encode(const void *data_in, size_t data_in_size,
void *base64_out, size_t *base64_out_size);
/**
* @brief Decodes a given base64 string and save the result to the given destination.
* @param[out] base64_in pointer to store the encoded base64 string
* @param[in] base64_in_size pointer to the variable containing the size of `base64_out.`
* @param[in] data_out pointer to the datum to encode
* @param[in, out] data_out_size the size of `data_out`.
This value is overwritten with the estimated size used for the
decoded string on BASE64_ERROR_BUFFER_OUT_SIZE.
This value is overwritten with the actual used size for the
decoded string on BASE64_SUCCESS.
* @returns BASE64_SUCCESS on success,
BASE64_ERROR_BUFFER_OUT_SIZE on insufficient size for decoding to `data_out`,
BASE64_ERROR_BUFFER_OUT if `data_out` equals NULL
but the size for `data_out_size` is sufficient,
BASE64_ERROR_DATA_IN if `base64_in` equals NULL,
BASE64_ERROR_DATA_IN_SIZE if `base64_in_size` is between 1 and 4.
*/
int base64_decode(const void *base64_in, size_t base64_in_size,
void *data_out, size_t *data_out_size);
#ifdef __cplusplus
}
#endif
/** @} */
#endif /* BASE64_H */