1 // crc.h - originally written and placed in the public domain by Wei Dai 2 3 /// \file crc.h 4 /// \brief Classes for CRC-32 and CRC-32C checksum algorithm 5 6 #ifndef CRYPTOPP_CRC32_H 7 #define CRYPTOPP_CRC32_H 8 9 #include "cryptlib.h" 10 11 NAMESPACE_BEGIN(CryptoPP) 12 13 const word32 CRC32_NEGL = 0xffffffffL; 14 15 #if (CRYPTOPP_LITTLE_ENDIAN) 16 #define CRC32_INDEX(c) (c & 0xff) 17 #define CRC32_SHIFTED(c) (c >> 8) 18 #else 19 #define CRC32_INDEX(c) (c >> 24) 20 #define CRC32_SHIFTED(c) (c << 8) 21 #endif 22 23 /// \brief CRC-32 Checksum Calculation 24 /// \details Uses CRC polynomial 0xEDB88320 25 class CRC32 : public HashTransformation 26 { 27 public: 28 CRYPTOPP_CONSTANT(DIGESTSIZE = 4); 29 CRC32(); 30 void Update(const byte *input, size_t length); 31 void TruncatedFinal(byte *hash, size_t size); DigestSize()32 unsigned int DigestSize() const {return DIGESTSIZE;} StaticAlgorithmName()33 CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {return "CRC32";} AlgorithmName()34 std::string AlgorithmName() const {return StaticAlgorithmName();} 35 UpdateByte(byte b)36 void UpdateByte(byte b) {m_crc = m_tab[CRC32_INDEX(m_crc) ^ b] ^ CRC32_SHIFTED(m_crc);} GetCrcByte(size_t i)37 byte GetCrcByte(size_t i) const {return reinterpret_cast<const byte *>(&m_crc)[i];} 38 39 std::string AlgorithmProvider() const; 40 41 protected: Reset()42 void Reset() {m_crc = CRC32_NEGL;} 43 44 private: 45 static const word32 m_tab[256]; 46 word32 m_crc; 47 }; 48 49 /// \brief CRC-32C Checksum Calculation 50 /// \details Uses CRC polynomial 0x82F63B78 51 /// \since Crypto++ 5.6.4 52 class CRC32C : public HashTransformation 53 { 54 public: 55 CRYPTOPP_CONSTANT(DIGESTSIZE = 4); 56 CRC32C(); 57 void Update(const byte *input, size_t length); 58 void TruncatedFinal(byte *hash, size_t size); DigestSize()59 unsigned int DigestSize() const {return DIGESTSIZE;} StaticAlgorithmName()60 CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {return "CRC32C";} AlgorithmName()61 std::string AlgorithmName() const {return StaticAlgorithmName();} 62 UpdateByte(byte b)63 void UpdateByte(byte b) {m_crc = m_tab[CRC32_INDEX(m_crc) ^ b] ^ CRC32_SHIFTED(m_crc);} GetCrcByte(size_t i)64 byte GetCrcByte(size_t i) const {return reinterpret_cast<const byte *>(&m_crc)[i];} 65 66 std::string AlgorithmProvider() const; 67 68 protected: Reset()69 void Reset() {m_crc = CRC32_NEGL;} 70 71 private: 72 static const word32 m_tab[256]; 73 word32 m_crc; 74 }; 75 76 NAMESPACE_END 77 78 #endif 79