43 lines
998 B
C++
43 lines
998 B
C++
#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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