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https://github.com/RfidResearchGroup/proxmark3.git
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48 lines
1.7 KiB
C
48 lines
1.7 KiB
C
//-----------------------------------------------------------------------------
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// This code is licensed to you under the terms of the GNU GPL, version 2 or,
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// at your option, any later version. See the LICENSE.txt file for the text of
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// the license.
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//-----------------------------------------------------------------------------
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// Generic CRC calculation code.
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//-----------------------------------------------------------------------------
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#ifndef __CRC_H
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#define __CRC_H
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#include <stdint.h>
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typedef struct crc {
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uint32_t state;
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int order;
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uint32_t polynom;
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uint32_t initial_value;
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uint32_t final_xor;
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uint32_t mask;
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} crc_t;
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/* Initialize a crc structure. order is the order of the polynom, e.g. 32 for a CRC-32
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* polynom is the CRC polynom. initial_value is the initial value of a clean state.
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* final_xor is XORed onto the state before returning it from crc_result(). */
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extern void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor);
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/* Update the crc state. data is the data of length data_width bits (only the the
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* data_width lower-most bits are used).
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*/
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extern void crc_update(crc_t *crc, uint32_t data, int data_width);
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/* Clean the crc state, e.g. reset it to initial_value */
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extern void crc_clear(crc_t *crc);
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/* Get the result of the crc calculation */
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extern uint32_t crc_finish(crc_t *crc);
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/* Static initialization of a crc structure */
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#define CRC_INITIALIZER(_order, _polynom, _initial_value, _final_xor) { \
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.state = ((_initial_value) & ((1L<<(_order))-1)), \
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.order = (_order), \
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.polynom = (_polynom), \
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.initial_value = (_initial_value), \
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.final_xor = (_final_xor), \
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.mask = ((1L<<(_order))-1) }
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#endif /* __CRC_H */
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