wsutil/crc16.h

   1 /** @file
   2  * Declaration of CRC-16 routines and table
   3  *
   4  * 2004 Richard van der Hoff <richardv@mxtelecom.com>
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * SPDX-License-Identifier: GPL-2.0-or-later
  11 */
  12
  13 #ifndef __CRC16_H__
  14 #define __CRC16_H__
  15
  16 #include <wireshark.h>
  17
  18 #ifdef __cplusplus
  19 extern "C" {
  20 #endif /* __cplusplus */
  21
  22 /* Calculate the CCITT/ITU/CRC-16 16-bit CRC
  23
  24    (parameters for this CRC are:
  25        Polynomial: x^16 + x^12 + x^5 + 1  (0x1021);
  26        Start value 0xFFFF;
  27        XOR result with 0xFFFF;
  28        First bit is LSB)
  29 */
  30
  31 /** Compute CRC16 CCITT checksum of a buffer of data.
  32  @param buf The buffer containing the data.
  33  @param len The number of bytes to include in the computation.
  34  @return The CRC16 CCITT checksum. */
  35 WS_DLL_PUBLIC uint16_t crc16_ccitt(const uint8_t *buf, unsigned len);
  36
  37 /** Compute CRC16 X.25 CCITT checksum of a buffer of data.
  38  @param buf The buffer containing the data.
  39  @param len The number of bytes to include in the computation.
  40  @return The CRC16 X.25 CCITT checksum. */
  41 WS_DLL_PUBLIC uint16_t crc16_x25_ccitt_seed(const uint8_t *buf, unsigned len, uint16_t seed);
  42
  43 /** Compute CRC16 CCITT checksum of a buffer of data.  If computing the
  44  *  checksum over multiple buffers and you want to feed the partial CRC16
  45  *  back in, remember to take the 1's complement of the partial CRC16 first.
  46  @param buf The buffer containing the data.
  47  @param len The number of bytes to include in the computation.
  48  @param seed The seed to use.
  49  @return The CRC16 CCITT checksum (using the given seed). */
  50 WS_DLL_PUBLIC uint16_t crc16_ccitt_seed(const uint8_t *buf, unsigned len, uint16_t seed);
  51
  52 /** Compute the 16bit CRC_A value of a buffer as defined in ISO14443-3.
  53  @param buf The buffer containing the data.
  54  @param len The number of bytes to include in the computation.
  55  @return the CRC16 checksum for the buffer */
  56 WS_DLL_PUBLIC uint16_t crc16_iso14443a(const uint8_t *buf, unsigned len);
  57
  58 /** Compute the 16bit CRC value of a buffer as defined in USB Specification.
  59  @param buf The buffer containing the data.
  60  @param len The number of bytes to include in the computation.
  61  @return the CRC16 checksum for the buffer */
  62 WS_DLL_PUBLIC uint16_t crc16_usb(const uint8_t *buf, unsigned len);
  63
  64 /** Calculates a CRC16 checksum for the given buffer with the polynom
  65  *  0x5935 using a precompiled CRC table
  66  * @param buf a pointer to a buffer of the given length
  67  * @param len the length of the given buffer
  68  * @param seed The seed to use.
  69  * @return the CRC16 checksum for the buffer
  70  */
  71 WS_DLL_PUBLIC uint16_t crc16_0x5935(const uint8_t *buf, uint32_t len, uint16_t seed);
  72
  73 /** Calculates a CRC16 checksum for the given buffer with the polynom
  74  *  0x755B using a precompiled CRC table
  75  * @param buf a pointer to a buffer of the given length
  76  * @param len the length of the given buffer
  77  * @param seed The seed to use.
  78  * @return the CRC16 checksum for the buffer
  79  */
  80 WS_DLL_PUBLIC uint16_t crc16_0x755B(const uint8_t *buf, uint32_t len, uint16_t seed);
  81
  82 /** Computes CRC16 checksum for the given data with the polynom 0x9949 using
  83  *  precompiled CRC table
  84  * @param buf a pointer to a buffer of the given length
  85  * @param len the length of the given buffer
  86  * @param seed The seed to use.
  87  * @return the CRC16 checksum for the buffer
  88  */
  89 WS_DLL_PUBLIC uint16_t crc16_0x9949_seed(const uint8_t *buf, unsigned len, uint16_t seed);
  90
  91 /** Computes CRC16 checksum for the given data with the polynom 0x3D65 using
  92  *  precompiled CRC table
  93  * @param buf a pointer to a buffer of the given length
  94  * @param len the length of the given buffer
  95  * @param seed The seed to use.
  96  * @return the CRC16 checksum for the buffer
  97  */
  98 WS_DLL_PUBLIC uint16_t crc16_0x3D65_seed(const uint8_t *buf, unsigned len, uint16_t seed);
  99
 100 /** Computes CRC16 checksum for the given data with the polynom 0x080F using
 101  *  precompiled CRC table
 102  * @param buf a pointer to a buffer of the given length
 103  * @param len the length of the given buffer
 104  * @param seed The seed to use.
 105  * @return the CRC16 checksum for the buffer
 106  */
 107 WS_DLL_PUBLIC uint16_t crc16_0x080F_seed(const uint8_t *buf, unsigned len, uint16_t seed);
 108
 109 #ifdef __cplusplus
 110 }
 111 #endif /* __cplusplus */
 112
 113 #endif /* crc16.h */