proxmark3/common/crc.h

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//-----------------------------------------------------------------------------
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// Generic CRC calculation code.
//-----------------------------------------------------------------------------
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#ifndef __CRC_H
#define __CRC_H
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#include "common.h" //stdint, stddef, stdbool
#include "util.h" // reflect, bswap_16
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typedef struct crc {
uint32_t state;
int order;
uint32_t polynom;
uint32_t initial_value;
uint32_t final_xor;
uint32_t mask;
int topbit;
bool refin; /* Parameter: Reflect input bytes? */
bool refout; /* Parameter: Reflect output CRC? */
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} 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().
* refin is the setting for reversing (bitwise) the bytes during crc
* refot is the setting for reversing (bitwise) the crc byte before returning it.
*/
extern void crc_init_ref(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor, bool refin, bool refout);
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/* 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
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* data_width lower-most bits are used).
*/
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extern void crc_update(crc_t *crc, uint32_t data, int data_width);
extern void crc_update2(crc_t *crc, uint32_t data, int data_width);
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/* 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);
// Calculate CRC-8/Maxim checksum
uint32_t CRC8Maxim(uint8_t *buff, size_t size);
// Calculate CRC-8 Mifare MAD checksum
uint32_t CRC8Mad(uint8_t *buff, size_t size);
// Calculate CRC-4/Legic checksum
uint32_t CRC4Legic(uint8_t *buff, size_t size);
// Calculate CRC-8/Legic checksum
uint32_t CRC8Legic(uint8_t *buff, size_t size);
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/* 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) \
.refin = false, \
.refout = false \
}
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#endif /* __CRC_H */