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42 lines
998 B
42 lines
998 B
#ifndef CRYPTOPP_CRC32_H |
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#define CRYPTOPP_CRC32_H |
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#include "cryptlib.h" |
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NAMESPACE_BEGIN(CryptoPP) |
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const word32 CRC32_NEGL = 0xffffffffL; |
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#ifdef IS_LITTLE_ENDIAN |
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#define CRC32_INDEX(c) (c & 0xff) |
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#define CRC32_SHIFTED(c) (c >> 8) |
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#else |
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#define CRC32_INDEX(c) (c >> 24) |
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#define CRC32_SHIFTED(c) (c << 8) |
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#endif |
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//! CRC Checksum Calculation |
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class CRC32 : public HashTransformation |
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{ |
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public: |
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CRYPTOPP_CONSTANT(DIGESTSIZE = 4) |
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CRC32(); |
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void Update(const byte *input, size_t length); |
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void TruncatedFinal(byte *hash, size_t size); |
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unsigned int DigestSize() const {return DIGESTSIZE;} |
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static const char * StaticAlgorithmName() {return "CRC32";} |
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std::string AlgorithmName() const {return StaticAlgorithmName();} |
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void UpdateByte(byte b) {m_crc = m_tab[CRC32_INDEX(m_crc) ^ b] ^ CRC32_SHIFTED(m_crc);} |
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byte GetCrcByte(size_t i) const {return ((byte *)&(m_crc))[i];} |
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private: |
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void Reset() {m_crc = CRC32_NEGL;} |
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static const word32 m_tab[256]; |
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word32 m_crc; |
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}; |
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NAMESPACE_END |
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#endif
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