sys_crc.h

/**
 * Copyright (c) 2016 - 2017 Nordic Semiconductor ASA and Luxoft Global Operations Gmbh.
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#ifndef SYS_CRC_H_INCLUDED
#define SYS_CRC_H_INCLUDED

#include <stdint.h>
#include <stddef.h>

/** @file
 * This file contains declarations of the CRC computing routines and necessary macros/types.
 *
 * @defgroup sys_crc System CRC API
 * @ingroup sys_15_4
 * @{
 * @brief Module to declare System CRC API.
 * @details The CRC module implements a set of routines to compute the 16-bit CRC value for octet arrays.
 */

/**
 * @brief Defines an initial value for the CRC sum.
 */
#define SYS_CRC_INIT              0

/**
 * @brief CRC value type. This module uses 16-bit CRC.
 */
typedef uint16_t sys_crc_t;

/**
 * @brief Function for computing CRC value for given data.
 *
 * @param[in] p_data   Pointer to data to compute.
 * @param[in] length   Length of data.
 *
 * @return Returns the CRC value for input data.
 */
sys_crc_t sys_crc_calc(const uint8_t * p_data, size_t length);

/**
 * @brief Function for updating the CRC value taking into the account the previously counted value.
 *
 * @details This function is used when input data is represented by several pieces.
 * Consequently, a call to this function for each piece will give a correct
 * total CRC value.
 *
 * @param[in] current_crc  Previously counted CRC value. Should be SYS_CRC_INIT for the first piece.
 * @param[in] p_data       Pointer to the current piece of data.
 * @param[in] length       Length of the current piece of data.
 *
 * @return Returns the updated CRC value.
 */
sys_crc_t sys_crc_continue(sys_crc_t current_crc, const uint8_t * p_data, size_t length);

/** @} */

#endif /* SYS_CRC_H_INCLUDED */