cvs.zerfleddert.de Git - proxmark3-svn/blob - 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 <stdint.h>             //uint32+
  13 #include <stdbool.h>    //bool
  14 #include <stddef.h>
  15 #include "util.h"       // reflect, bswap_16
  16
  17 typedef struct crc {
  18         uint32_t state;
  19         int order;
  20         uint32_t polynom;
  21         uint32_t initial_value;
  22         uint32_t final_xor;
  23         uint32_t mask;
  24         int topbit;
  25         bool refin;    /* Parameter: Reflect input bytes?        */
  26         bool refout;   /* Parameter: Reflect output CRC?         */
  27 } crc_t;
  28
  29 /* Initialize a crc structure. order is the order of the polynom, e.g. 32 for a CRC-32
  30  * polynom is the CRC polynom. initial_value is the initial value of a clean state.
  31  * final_xor is XORed onto the state before returning it from crc_result().
  32  * refin is the setting for reversing (bitwise) the bytes during crc
  33  * refot is the setting for reversing (bitwise) the crc byte before returning it.
  34  */
  35 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);
  36
  37 /* Initialize a crc structure. order is the order of the polynom, e.g. 32 for a CRC-32
  38  * polynom is the CRC polynom. initial_value is the initial value of a clean state.
  39  * final_xor is XORed onto the state before returning it from crc_result(). */
  40 extern void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor);
  41
  42
  43 /* Update the crc state. data is the data of length data_width bits (only the
  44  * data_width lower-most bits are used).
  45  */
  46 extern void crc_update(crc_t *crc, uint32_t data, int data_width);
  47
  48 /* Clean the crc state, e.g. reset it to initial_value */
  49 extern void crc_clear(crc_t *crc);
  50
  51 /* Get the result of the crc calculation */
  52 extern uint32_t crc_finish(crc_t *crc);
  53
  54 // Calculate CRC-8/Maxim checksum
  55 uint32_t CRC8Maxim(uint8_t *buff, size_t size);
  56
  57 // Calculate CRC-4/Legic checksum
  58 uint32_t CRC4Legic(uint8_t *buff, size_t size);
  59
  60 // Calculate CRC-8/Legic checksum
  61 uint32_t CRC8Legic(uint8_t *buff, size_t size);
  62
  63 // Calculate CRC-16/Legic checksum
  64 // the initial_value is based on the previous legic_Crc8 of the UID.
  65 // ie:  uidcrc = 0x78  then initial_value == 0x7878
  66 uint32_t CRC16Legic(uint8_t *buff, size_t size, uint8_t uidcrc);
  67
  68 // test crc 16.
  69 uint32_t CRC16_DNP(uint8_t *buff, size_t size);
  70 uint32_t CRC16_CCITT(uint8_t *buff, size_t size);
  71
  72 /* Static initialization of a crc structure */
  73 #define CRC_INITIALIZER(_order, _polynom, _initial_value, _final_xor) { \
  74         .state = ((_initial_value) & ((1L<<(_order))-1)), \
  75         .order = (_order), \
  76         .polynom = (_polynom), \
  77         .initial_value = (_initial_value), \
  78         .final_xor = (_final_xor), \
  79         .mask = ((1L<<(_order))-1) \
  80         .refin = FALSE, \
  81         .refout = FALSE \
  82         }
  83
  84 #endif /* __CRC_H */