common/crc.h

   1 //-----------------------------------------------------------------------------
   2 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
   3 // at your option, any later version. See the LICENSE.txt file for the text of
   4 // the license.
   5 //-----------------------------------------------------------------------------
   6 // Generic CRC calculation code.
   7 //-----------------------------------------------------------------------------
   8
   9 #ifndef __CRC_H
  10 #define __CRC_H
  11
  12 #include "common.h"
  13
  14 typedef struct crc_ctx {
  15     uint32_t state;
  16     int order;
  17     uint32_t polynom;
  18     uint32_t initial_value;
  19     uint32_t final_xor;
  20     uint32_t mask;
  21     int topbit;
  22     bool refin;    /* Parameter: Reflect input bytes?        */
  23     bool refout;   /* Parameter: Reflect output CRC?         */
  24 } crc_t;
  25
  26 /* Static initialization of a crc structure */
  27 #define CRC_INITIALIZER(_order, _polynom, _initial_value, _final_xor) { \
  28     .state = ((_initial_value) & ((1L<<(_order))-1)), \
  29     .order = (_order), \
  30     .polynom = (_polynom), \
  31     .initial_value = (_initial_value), \
  32     .final_xor = (_final_xor), \
  33     .mask = ((1L<<(_order))-1) \
  34     .refin = false, \
  35     .refout = false \
  36 }
  37
  38 /* Initialize a crc structure. order is the order of the polynom, e.g. 32 for a CRC-32
  39  * polynom is the CRC polynom. initial_value is the initial value of a clean state.
  40  * final_xor is XORed onto the state before returning it from crc_result().
  41  * refin is the setting for reversing (bitwise) the bytes during crc
  42  * refot is the setting for reversing (bitwise) the crc byte before returning it.
  43  */
  44 void crc_init_ref(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor, bool refin, bool refout);
  45
  46 /* Initialize a crc structure. order is the order of the polynom, e.g. 32 for a CRC-32
  47  * polynom is the CRC polynom. initial_value is the initial value of a clean state.
  48  * final_xor is XORed onto the state before returning it from crc_result(). */
  49 void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor);
  50
  51
  52 /* Update the crc state. data is the data of length data_width bits (only the
  53  * data_width lower-most bits are used).
  54  */
  55 void crc_update(crc_t *crc, uint32_t data, int data_width);
  56 void crc_update2(crc_t *crc, uint32_t data, int data_width);
  57
  58 /* Clean the crc state, e.g. reset it to initial_value */
  59 void crc_clear(crc_t *crc);
  60
  61 /* Get the result of the crc calculation */
  62 uint32_t crc_finish(crc_t *crc);
  63
  64 // Calculate CRC-8/Maxim checksum
  65 uint32_t CRC8Maxim(uint8_t *buff, size_t size);
  66
  67 // Calculate CRC-8 Mifare MAD checksum
  68 uint32_t CRC8Mad(uint8_t *buff, size_t size);
  69
  70 // Calculate CRC-4/Legic checksum
  71 uint32_t CRC4Legic(uint8_t *buff, size_t size);
  72
  73 // Calculate CRC-8/Legic checksum
  74 uint32_t CRC8Legic(uint8_t *buff, size_t size);
  75
  76 // Calculate CRC-8/Cardx checksum
  77 uint32_t CRC8Cardx(uint8_t *buff, size_t size);
  78 #endif /* __CRC_H */