md5.h

C++ patterns设计模式

// MD5报文摘要
// 使用方法请参考文件最后部分

#ifndef INCLUDED_MD5_H
#define INCLUDED_MD5_H

#if defined(HAS_PRAGMA_ONCE)
#pragma PRAGMA_ONCE_DECLARE
#endif


class MD5 
{
    // first, some types for exact size
    typedef unsigned       int  uint4;
    typedef unsigned short int  uint2;
    typedef unsigned char       uint1;

public:
    // methods for controlled operation:
    void init();               // called by all constructors
    void update(unsigned char *input, unsigned int input_length);
    void final();

    void digest(unsigned char *output);

    // for private MD5 digest to change, don't use this method handy
    void changeMagicNumber(uint4 m1, uint4 m2, uint4 m3, uint4 m4);

private:
    void transform        (uint1 *buffer);  // does the real update work.  Note 
                                            // that length is implied to be 64.
    static void encode    (uint1 *dest, uint4 *src, uint4 length);
    static void decode    (uint4 *dest, uint1 *src, uint4 length);
    static inline void memcpy    (uint1 *dest, uint1 *src, uint4 length);
    static inline void memset    (uint1 *start, uint1 val, uint4 length);

    static inline uint4  rotate_left (uint4 x, uint4 n);
    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 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);

private:
    uint4 m_state[4];
    uint4 m_count[2];     // number of *bits*, mod 2^64
    uint1 m_buffer[64];   // input buffer
    uint1 m_digest[16];
    bool  m_finalized;
};

class MD5Ext
{
public:
    // do the MD5 digest with full input
    MD5Ext(char *input, size_t length);
    // return the digest as raw data format, 
    // output must big or equal than 16 bytes
    void digest(char *output);
    // return the digest as hex string format for print etc.
    void digest(std::string &output);
private:
    MD5 m_ctx;
};

void md5digest(char* output, char* input, size_t insize);

// RFC中第一次出现的函数接口名字
void md5_calc(unsigned char *output, unsigned char *input, unsigned int inlen);

#endif

/******************************************************************************
Usage                   :
1. first scenario :
    // This method give you the full control of the process, 
    // it fit for stream input data.
    MD5 md5;
    md5.init();
    // read some data to "input"
    md5.update(input, insize);
    // read more data to "input"
    md5.update(input, insize);
    //...
    //all data read
    md5.final();
    //get the digest
    unsigned char output[16];
    md5.digest(output);
2. second scenario :    
    // This method give you an easy way to do the MD5 digest,
    // all the input data must present at first.
    // read all data into "input";
    MD5Ext md5(input, insize);
    // get the digest with original format
    char output[16];
    md5.digest(output);
    // or get the digest with hex string format
    std::string hexdigest;
    md5.digest(hexdigest);
3. third scenario :
    // This method give you only one API to do all things
    //read all data into "input", alloc space for "output"
    md5digest(output, input, insize);
******************************************************************************/