/** * \file * Functions and types for CRC checks. * * Generated on Sat Jun 15 14:34:05 2019 * by pycrc v0.9.2, https://pycrc.org * using the configuration: * - Width = 16 * - Poly = 0xed2f * - XorIn = 0xbeef * - ReflectIn = False * - XorOut = 0x0000 * - ReflectOut = False * - Algorithm = table-driven * * This file defines the functions NVM_CRC_init(), NVM_CRC_update() and NVM_CRC_finalize(). * * The NVM_CRC_init() function returns the inital \c crc value and must be called * before the first call to NVM_CRC_update(). * Similarly, the NVM_CRC_finalize() function must be called after the last call * to NVM_CRC_update(), before the \c crc is being used. * is being used. * * The NVM_CRC_update() function can be called any number of times (including zero * times) in between the NVM_CRC_init() and NVM_CRC_finalize() calls. * * This pseudo-code shows an example usage of the API: * \code{.c} * NVM_CRC_t crc; * unsigned char data[MAX_DATA_LEN]; * size_t data_len; * * crc = NVM_CRC_init(); * while ((data_len = read_data(data, MAX_DATA_LEN)) > 0) { * crc = NVM_CRC_update(crc, data, data_len); * } * crc = NVM_CRC_finalize(crc); * \endcode * * ## Additional Notes * * The CRC polynomial (0xED2F) was chosen based on the research published by Philip Koopman of Carnegie Mellon * University [here](http://users.ece.cmu.edu/~koopman/crc/). Dr. Koopman claims this polynomial has a * Hamming Distance of 10. * * The initial value, 0xBEEF, was chosen simply to avoid the most common EE values of 0xFFFF and 0x0000. * */ #ifndef NVM_CRC_H #define NVM_CRC_H #include #include #ifdef __cplusplus extern "C" { #endif /** * The definition of the used algorithm. * * This is not used anywhere in the generated code, but it may be used by the * application code to call algorithm-specific code, if desired. */ #define CRC_ALGO_TABLE_DRIVEN 1 /** * The type of the CRC values. * * CRCs are sixteen bits wide. */ typedef uint16_t NVM_CRC_t; /** * Calculate the initial crc value. * * \return The initial crc value. */ static inline NVM_CRC_t NVM_CRC_init(void) { return 0xbeef; } /** * Update the crc value with new data. * * \param[in] crc The current crc value. * \param[in] data Pointer to a buffer of \a data_len bytes. * \param[in] data_len Number of bytes in the \a data buffer. * \return The updated crc value. */ NVM_CRC_t NVM_CRC_update(NVM_CRC_t crc, const void *data, size_t data_len); /** * Calculate the final crc value. * * \param[in] crc The current crc value. * \return The final crc value. */ static inline NVM_CRC_t NVM_CRC_finalize(NVM_CRC_t crc) { return crc; } #ifdef __cplusplus } /* closing brace for extern "C" */ #endif #endif /* NVM_CRC_H */