crc.h

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/*
 * @file crc.h
 * @brief Cyclic Redundancy Check (CRC)
 *
 * NOTE:
 *  Only CRC24 supported at the moment
 *
 * Copyright (c) 2008-2018 by the GPSD project
 * SPDX-License-Identifier: BSD-2-clause
 * https://spdx.org/licenses/BSD-2-Clause.html
 */
 
#ifndef CRC_H_
#define CRC_H_
 
#include <cstdint>
 
#include "message.h"
 
// Generating polynomial
// G_CRC_24_A(D) = [D24 + D23 + D18 + D17 + D14 + D11 + D10 + D7 + D6 + D5 + D4
// + D3 + D + 1]
#define G_CRC_24A (0x1864CFBu;)  // Normal representation
#define CRCSEED (0)              // could be non-zero to detect leading zeros
 
// CRC segments
#define LO(x) (unsigned char)((x)&0xff)
#define MID(x) (unsigned char)(((x) >> 8) & 0xff)
#define HI(x) (unsigned char)(((x) >> 16) & 0xff)
 
class DoCRC {
 private:
  const uint32_t crc24_table_[256];
 
 public:
  DoCRC()
      : crc24_table_{
            0x00000000u, 0x01864CFBu, 0x028AD50Du, 0x030C99F6u, 0x0493E6E1u,
            0x0515AA1Au, 0x061933ECu, 0x079F7F17u, 0x08A18139u, 0x0927CDC2u,
            0x0A2B5434u, 0x0BAD18CFu, 0x0C3267D8u, 0x0DB42B23u, 0x0EB8B2D5u,
            0x0F3EFE2Eu, 0x10C54E89u, 0x11430272u, 0x124F9B84u, 0x13C9D77Fu,
            0x1456A868u, 0x15D0E493u, 0x16DC7D65u, 0x175A319Eu, 0x1864CFB0u,
            0x19E2834Bu, 0x1AEE1ABDu, 0x1B685646u, 0x1CF72951u, 0x1D7165AAu,
            0x1E7DFC5Cu, 0x1FFBB0A7u, 0x200CD1E9u, 0x218A9D12u, 0x228604E4u,
            0x2300481Fu, 0x249F3708u, 0x25197BF3u, 0x2615E205u, 0x2793AEFEu,
            0x28AD50D0u, 0x292B1C2Bu, 0x2A2785DDu, 0x2BA1C926u, 0x2C3EB631u,
            0x2DB8FACAu, 0x2EB4633Cu, 0x2F322FC7u, 0x30C99F60u, 0x314FD39Bu,
            0x32434A6Du, 0x33C50696u, 0x345A7981u, 0x35DC357Au, 0x36D0AC8Cu,
            0x3756E077u, 0x38681E59u, 0x39EE52A2u, 0x3AE2CB54u, 0x3B6487AFu,
            0x3CFBF8B8u, 0x3D7DB443u, 0x3E712DB5u, 0x3FF7614Eu, 0x4019A3D2u,
            0x419FEF29u, 0x429376DFu, 0x43153A24u, 0x448A4533u, 0x450C09C8u,
            0x4600903Eu, 0x4786DCC5u, 0x48B822EBu, 0x493E6E10u, 0x4A32F7E6u,
            0x4BB4BB1Du, 0x4C2BC40Au, 0x4DAD88F1u, 0x4EA11107u, 0x4F275DFCu,
            0x50DCED5Bu, 0x515AA1A0u, 0x52563856u, 0x53D074ADu, 0x544F0BBAu,
            0x55C94741u, 0x56C5DEB7u, 0x5743924Cu, 0x587D6C62u, 0x59FB2099u,
            0x5AF7B96Fu, 0x5B71F594u, 0x5CEE8A83u, 0x5D68C678u, 0x5E645F8Eu,
            0x5FE21375u, 0x6015723Bu, 0x61933EC0u, 0x629FA736u, 0x6319EBCDu,
            0x648694DAu, 0x6500D821u, 0x660C41D7u, 0x678A0D2Cu, 0x68B4F302u,
            0x6932BFF9u, 0x6A3E260Fu, 0x6BB86AF4u, 0x6C2715E3u, 0x6DA15918u,
            0x6EADC0EEu, 0x6F2B8C15u, 0x70D03CB2u, 0x71567049u, 0x725AE9BFu,
            0x73DCA544u, 0x7443DA53u, 0x75C596A8u, 0x76C90F5Eu, 0x774F43A5u,
            0x7871BD8Bu, 0x79F7F170u, 0x7AFB6886u, 0x7B7D247Du, 0x7CE25B6Au,
            0x7D641791u, 0x7E688E67u, 0x7FEEC29Cu, 0x803347A4u, 0x81B50B5Fu,
            0x82B992A9u, 0x833FDE52u, 0x84A0A145u, 0x8526EDBEu, 0x862A7448u,
            0x87AC38B3u, 0x8892C69Du, 0x89148A66u, 0x8A181390u, 0x8B9E5F6Bu,
            0x8C01207Cu, 0x8D876C87u, 0x8E8BF571u, 0x8F0DB98Au, 0x90F6092Du,
            0x917045D6u, 0x927CDC20u, 0x93FA90DBu, 0x9465EFCCu, 0x95E3A337u,
            0x96EF3AC1u, 0x9769763Au, 0x98578814u, 0x99D1C4EFu, 0x9ADD5D19u,
            0x9B5B11E2u, 0x9CC46EF5u, 0x9D42220Eu, 0x9E4EBBF8u, 0x9FC8F703u,
            0xA03F964Du, 0xA1B9DAB6u, 0xA2B54340u, 0xA3330FBBu, 0xA4AC70ACu,
            0xA52A3C57u, 0xA626A5A1u, 0xA7A0E95Au, 0xA89E1774u, 0xA9185B8Fu,
            0xAA14C279u, 0xAB928E82u, 0xAC0DF195u, 0xAD8BBD6Eu, 0xAE872498u,
            0xAF016863u, 0xB0FAD8C4u, 0xB17C943Fu, 0xB2700DC9u, 0xB3F64132u,
            0xB4693E25u, 0xB5EF72DEu, 0xB6E3EB28u, 0xB765A7D3u, 0xB85B59FDu,
            0xB9DD1506u, 0xBAD18CF0u, 0xBB57C00Bu, 0xBCC8BF1Cu, 0xBD4EF3E7u,
            0xBE426A11u, 0xBFC426EAu, 0xC02AE476u, 0xC1ACA88Du, 0xC2A0317Bu,
            0xC3267D80u, 0xC4B90297u, 0xC53F4E6Cu, 0xC633D79Au, 0xC7B59B61u,
            0xC88B654Fu, 0xC90D29B4u, 0xCA01B042u, 0xCB87FCB9u, 0xCC1883AEu,
            0xCD9ECF55u, 0xCE9256A3u, 0xCF141A58u, 0xD0EFAAFFu, 0xD169E604u,
            0xD2657FF2u, 0xD3E33309u, 0xD47C4C1Eu, 0xD5FA00E5u, 0xD6F69913u,
            0xD770D5E8u, 0xD84E2BC6u, 0xD9C8673Du, 0xDAC4FECBu, 0xDB42B230u,
            0xDCDDCD27u, 0xDD5B81DCu, 0xDE57182Au, 0xDFD154D1u, 0xE026359Fu,
            0xE1A07964u, 0xE2ACE092u, 0xE32AAC69u, 0xE4B5D37Eu, 0xE5339F85u,
            0xE63F0673u, 0xE7B94A88u, 0xE887B4A6u, 0xE901F85Du, 0xEA0D61ABu,
            0xEB8B2D50u, 0xEC145247u, 0xED921EBCu, 0xEE9E874Au, 0xEF18CBB1u,
            0xF0E37B16u, 0xF16537EDu, 0xF269AE1Bu, 0xF3EFE2E0u, 0xF4709DF7u,
            0xF5F6D10Cu, 0xF6FA48FAu, 0xF77C0401u, 0xF842FA2Fu, 0xF9C4B6D4u,
            0xFAC82F22u, 0xFB4E63D9u, 0xFCD11CCEu, 0xFD575035u, 0xFE5BC9C3u,
            0xFFDD8538u} {}
  ~DoCRC() = default;
 
  /* Initialize CRC:
   * Not used at the moment. We decided to pre-generate the tables and
   * harcode them here. Left function just for reference
   */
  static void InitCrc24(uint32_t table[256]);
 
  uint32_t CalculateCrc24(const unsigned char* data, int len);
 
  /*
   * Compute and add CRC to packet
   */
  void AddCrc24(MacPacketPacked* p);
 
  /*
   * Verify CRC
   */
  bool CheckCrc24(unsigned char* data, int len, uint32_t ref_crc);
};
 
#endif  // CRC_H_