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Add generic CRC calculation code

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henryk@ploetzli.ch 2009-11-25 20:41:41 +00:00
commit 68d9d60a4d
3 changed files with 90 additions and 1 deletions
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include/crc.h Normal file
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/*
* crc.h
*
* Generic CRC calculation code.
*
*/
#ifndef CRC_H_
#define CRC_H_
#include <stdint.h>
typedef struct crc {
uint32_t state;
int order;
uint32_t polynom;
uint32_t initial_value;
uint32_t final_xor;
uint32_t mask;
} crc_t;
/* Initialize a crc structure. order is the order of the polynom, e.g. 32 for a CRC-32
* polynom is the CRC polynom. initial_value is the initial value of a clean state.
* final_xor is XORed onto the state before returning it from crc_result(). */
extern void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor);
/* Update the crc state. data is the data of length data_width bits (only the the
* data_width lower-most bits are used).
*/
extern void crc_update(crc_t *crc, uint32_t data, int data_width);
/* Clean the crc state, e.g. reset it to initial_value */
extern void crc_clear(crc_t *crc);
/* Get the result of the crc calculation */
extern uint32_t crc_finish(crc_t *crc);
/* Static initialization of a crc structure */
#define CRC_INITIALIZER(_order, _polynom, _initial_value, _final_xor) { \
.state = ((_initial_value) & ((1L<<(_order))-1)), \
.order = (_order), \
.polynom = (_polynom), \
.initial_value = (_initial_value), \
.final_xor = (_final_xor), \
.mask = ((1L<<(_order))-1) }
#endif /* CRC_H_ */