#ifndef __OTA_MD5_H__
#define __OTA_MD5_H__

#if defined(__cplusplus)
extern "C" {
#endif


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

/**
 * \brief          MD5 context structure
 *
 * \warning        MD5 is considered a weak message digest and its use
 *                 constitutes a security risk. We recommend considering
 *                 stronger message digests instead.
 *
 */
typedef struct {
    uint32_t total[2];          /*!< number of bytes processed  */
    uint32_t state[4];          /*!< intermediate digest state  */
    unsigned char buffer[64];   /*!< data block being processed */
} utils_md5_context_t;

/**
 * \brief          Initialize MD5 context
 *
 * \param ctx      MD5 context to be initialized
 *
 * \warning        MD5 is considered a weak message digest and its use
 *                 constitutes a security risk. We recommend considering
 *                 stronger message digests instead.
 *
 */
void utils_md5_init(utils_md5_context_t *ctx);

/**
 * \brief          Clear MD5 context
 *
 * \param ctx      MD5 context to be cleared
 *
 * \warning        MD5 is considered a weak message digest and its use
 *                 constitutes a security risk. We recommend considering
 *                 stronger message digests instead.
 *
 */
void utils_md5_free(utils_md5_context_t *ctx);

/**
 * \brief          MD5 context setup
 *
 * \param ctx      context to be initialized
 *
 * \return         0 if successful
 *
 * \warning        MD5 is considered a weak message digest and its use
 *                 constitutes a security risk. We recommend considering
 *                 stronger message digests instead.
 *
 */
int32_t utils_md5_starts(utils_md5_context_t *ctx);

/**
 * \brief          MD5 process buffer
 *
 * \param ctx      MD5 context
 * \param input    buffer holding the data
 * \param ilen     length of the input data
 *
 * \return         0 if successful
 *
 * \warning        MD5 is considered a weak message digest and its use
 *                 constitutes a security risk. We recommend considering
 *                 stronger message digests instead.
 *
 */
int32_t utils_md5_update(utils_md5_context_t *ctx,
                         const unsigned char *input,
                         uint32_t ilen);

/**
 * \brief          MD5 final digest
 *
 * \param ctx      MD5 context
 * \param output   MD5 checksum result
 *
 * \return         0 if successful
 *
 * \warning        MD5 is considered a weak message digest and its use
 *                 constitutes a security risk. We recommend considering
 *                 stronger message digests instead.
 *
 */
int32_t utils_md5_finish(utils_md5_context_t *ctx,
                         unsigned char output[16]);

/**
 * \brief          MD5 process data block (internal use only)
 *
 * \param ctx      MD5 context
 * \param data     buffer holding one block of data
 *
 * \return         0 if successful
 *
 * \warning        MD5 is considered a weak message digest and its use
 *                 constitutes a security risk. We recommend considering
 *                 stronger message digests instead.
 *
 */
int32_t utils_internal_md5_process(utils_md5_context_t *ctx,
                                   const unsigned char data[64]);

/**
 * \brief          Output = MD5( input buffer )
 *
 * \param input    buffer holding the data
 * \param ilen     length of the input data
 * \param output   MD5 checksum result
 *
 * \return         0 if successful
 *
 * \warning        MD5 is considered a weak message digest and its use
 *                 constitutes a security risk. We recommend considering
 *                 stronger message digests instead.
 *
 */
#if defined(__cplusplus)
}
#endif

#endif  /* __OTA_MD5_H__ */