MD5.h

// Copyright eeGeo Ltd (2012-2014), All Rights Reserved

#ifndef BZF_MD5_H
#define BZF_MD5_H

#include <cstring>
#include <iostream>

namespace Eegeo
{
    namespace Helpers
    {
        // a small class for calculating MD5 hashes of strings or byte arrays
        // it is not meant to be fast or secure
        //
        // usage: 1) feed it blocks of uchars with update()
        //      2) finalize()
        //      3) get hexdigest() string
        //      or
        //      MD5(std::string).hexdigest()
        //
        // assumes that char is 8 bit and int is 32 bit
        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);
    }
}

#endif