md5算法的c++实现

看到一个不错的c++实现的md5算法 class MD5 { public: typedef unsigned int size_type; // must be 32bit MD5(); MD5(const std::string& text); void update(const unsigned char *buf, size_type length); void update(const char *buf, size_type length); MD5& finalize(); std::string hexdigest() const; friend std::ostream& operator<<(std::ostream&, MD5 md5); private: void init(); typedef unsigned char uint1; // 8bit typedef unsigned int uint4; // 32bit enum {blocksize = 64}; // VC6 won't eat a const static int here void transform(const uint1 block[blocksize]); static void decode(uint4 output[], const uint1 input[], size_type len); static void encode(uint1 output[], const uint4 input[], size_type len); bool finalized; uint1 buffer[blocksize]; // bytes that didn't fit in last 64 byte chunk uint4 count[2]; // 64bit counter for number of bits (lo, hi) uint4 state[4]; // digest so far uint1 digest[16]; // the result // low level logic operations static inline uint4 F(uint4 x, uint4 y, uint4 z); static inline uint4 G(uint4 x, uint4 y, uint4 z); static inline uint4 H(uint4 x, uint4 y, uint4 z); static inline uint4 I(uint4 x, uint4 y, uint4 z); static inline uint4 rotate_left(uint4 x, int n); static inline void FF(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac); static inline void GG(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac); static inline void HH(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac); static inline void II(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac); }; std::string md5(const std::string &str);