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