一个用C++实现的MD5类

//Filename: CMd5.h

#include <windows.h>
#include <fstream>
using namespace std;

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

typedef LONGLONG LONG64;

#define ENGLISH  //指定错误信息为英文

class CMd5
{
public:
CMd5();
CMd5(char *filename);
~CMd5();

LPCSTR TargetFile(char *filename=NULL);  //求文件的MD5值
void TargetStr(LPCSTR str);              //求字符串的MD5值
LPCSTR GetDigestKey();                   //得到所求结果

LPCSTR GetErr();

private:
inline ULONG LRotate(ULONG Sdata,int nBit);
inline ULONG F(ULONG x,ULONG y,ULONG z);
inline ULONG G(ULONG x,ULONG y,ULONG z);
inline ULONG H(ULONG x,ULONG y,ULONG z);
inline ULONG I(ULONG x,ULONG y,ULONG z);
inline void FF(ULONG &a,ULONG b,ULONG c,ULONG d,ULONG Msg,int nBit,ULONG Cnt);
inline void GG(ULONG &a,ULONG b,ULONG c,ULONG d,ULONG Msg,int nBit,ULONG Cnt);
inline void HH(ULONG &a,ULONG b,ULONG c,ULONG d,ULONG Msg,int nBit,ULONG Cnt);
inline void II(ULONG &a,ULONG b,ULONG c,ULONG d,ULONG Msg,int nBit,ULONG Cnt);

bool Init();
bool OpenFile();
bool Read64Byte();
void TransForm();
bool CaculateFile();
bool CaculateStr(LPCSTR str);
void SetErr(int nErr);
void JustifytoStr();

fstream Sfile;
ULONG *pM;
LPVOID Pointer;
ULONG T[4];
bool IsSuc;
char fname[MAX_PATH];
LONG64 FileLen;
static const ULONG Context[4];
static const LPSTR ErrInfo[5][2];
char strErr[50];
char Digest[33];
};

//Filename: CMd5.cpp

#include "CMd5.h"

const ULONG CMd5::Context[4] = { 0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476 };

const LPSTR CMd5::ErrInfo[5][2] = {
{"",""},
{"The Memory is not enough !","内存分配失败!"},
{"Have not assign a file !","未指定文件!"},
{"Have not assign the text !","未指定文本!"},
{"Have something wrong with MD5!","有错误发生!"},
};

//==========================<内联函数实现>=========================================
ULONG CMd5::LRotate(ULONG Sdata,int nBit)
{
return (Sdata<<nBit)|(Sdata>>(32-nBit));
}

ULONG CMd5::F(ULONG x,ULONG y,ULONG z)
{
return (x&y)|((~x)&z);
}

ULONG CMd5::G(ULONG x,ULONG y,ULONG z)
{
return (x&z)|(y&(~z));
}

ULONG CMd5::H(ULONG x,ULONG y,ULONG z)
{
return x^y^z;
}

ULONG CMd5::I(ULONG x,ULONG y,ULONG z)
{
return y^(x|(~z));
}

void CMd5::FF(ULONG &a,ULONG b,ULONG c,ULONG d,ULONG Msg,int nBit,ULONG Cnt)
{
a+=F(b,c,d)+Msg+(ULONG)Cnt;
a=LRotate(a,nBit);
a+=b;
}

void CMd5::GG(ULONG &a,ULONG b,ULONG c,ULONG d,ULONG Msg,int nBit,ULONG Cnt)
{
a+=G(b,c,d)+Msg+(ULONG)Cnt;
a=LRotate(a,nBit);
a+=b;
}

void CMd5::HH(ULONG &a,ULONG b,ULONG c,ULONG d,ULONG Msg,int nBit,ULONG Cnt)
{
a+=H(b,c,d)+Msg+(ULONG)Cnt;
a=LRotate(a,nBit);
a+=b;
}

void CMd5::II(ULONG &a,ULONG b,ULONG c,ULONG d,ULONG Msg,int nBit,ULONG Cnt)
{
a+=I(b,c,d)+Msg+(ULONG)Cnt;
a=LRotate(a,nBit);
a+=b;
}

//==========================<成员函数实现>======================================
CMd5::CMd5()
{
IsSuc=false;
Pointer=NULL;
memset(strErr,0,50);
}

CMd5::CMd5(char *filename)
{
IsSuc=false;
Pointer=NULL;
memset(strErr,0,50);
TargetFile(filename);
}

CMd5::~CMd5()
{
if(Sfile.is_open())
{
Sfile.close();
}

if(Pointer)
{
delete[] Pointer;
Pointer=NULL;
}
}

LPCSTR CMd5::TargetFile(char *filename)
{
if(!Init())
{
SetErr(1);
}

static char temp[MAX_PATH];
strcpy(temp,fname);
strcpy(fname,filename);

CaculateFile();

return temp;
}

void CMd5::TargetStr(LPCSTR str)
{
if(!Init())
{
SetErr(1);
}

CaculateStr(str);
}

bool CMd5::Init()
{
*fname='/0';
IsSuc=true;
*Digest='/0';

try
{
Pointer=new BYTE[sizeof(ULONG)*16];
}
catch(bad_alloc w)
{
Pointer=NULL;
SetErr(1);
}

pM=(ULONG*)Pointer;
FileLen=0;

for(int i=0;i<4;i++)
{
T[i]=Context[i];
}

return true;
}

bool CMd5::OpenFile()
{
Sfile.open(fname,ios::in|ios::binary);
if( Sfile.fail() )
{
SetErr(0);
return false;
}

return true;
}

bool CMd5::Read64Byte()
{
static bool rb=true;
int n;

if(!Sfile.eof())
{
Sfile.read((char*)Pointer,sizeof(ULONG)*16);
FileLen+=n=Sfile.gcount();

if(n<64)
{
char* p=(char*)Pointer+n;
memset((void *)p,0,64-n);
*p=(char)0x80;
rb=false;

if(n<56)
{
LONG64 *pt=(LONG64*)Pointer+7;
*pt=FileLen*8;

return false;
}
}

return true;
}
else
{
memset(Pointer,0,64);

if(rb)
{
*(char*)Pointer=(char)0x80;
}

LONG64 *pt=(LONG64 *)Pointer+7;

*pt=FileLen*8;

return false;
}
}

void CMd5::TransForm()
{
MSG msg;

while(PeekMessage(&msg,NULL,0,0,PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}

ULONG a=T[0],b=T[1],c=T[2],d=T[3];

//第一轮-------------------------------->
FF (a, b, c, d, pM[ 0], S11, 0xd76aa478); //- 1 -
FF (d, a, b, c, pM[ 1], S12, 0xe8c7b756); //- 2 -
FF (c, d, a, b, pM[ 2], S13, 0x242070db); //- 3 -
FF (b, c, d, a, pM[ 3], S14, 0xc1bdceee); //- 4 -
FF (a, b, c, d, pM[ 4], S11, 0xf57c0faf); //- 5 -
FF (d, a, b, c, pM[ 5], S12, 0x4787c62a); //- 6 -
FF (c, d, a, b, pM[ 6], S13, 0xa8304613); //- 7 -
FF (b, c, d, a, pM[ 7], S14, 0xfd469501); //- 8 -
FF (a, b, c, d, pM[ 8], S11, 0x698098d8); //- 9 -
FF (d, a, b, c, pM[ 9], S12, 0x8b44f7af); //- 10 -
FF (c, d, a, b, pM[10], S13, 0xffff5bb1); //- 11 -
FF (b, c, d, a, pM[11], S14, 0x895cd7be); //- 12 -
FF (a, b, c, d, pM[12], S11, 0x6b901122); //- 13 -
FF (d, a, b, c, pM[13], S12, 0xfd987193); //- 14 -
FF (c, d, a, b, pM[14], S13, 0xa679438e); //- 15 -
FF (b, c, d, a, pM[15], S14, 0x49b40821); //- 16 -

//第二轮--------------------------------->
GG (a, b, c, d, pM[ 1], S21, 0xf61e2562); //- 17 -
GG (d, a, b, c, pM[ 6], S22, 0xc040b340); //- 18 -
GG (c, d, a, b, pM[11], S23, 0x265e5a51); //- 19 -
GG (b, c, d, a, pM[ 0], S24, 0xe9b6c7aa); //- 20 -
GG (a, b, c, d, pM[ 5], S21, 0xd62f105d); //- 21 -
GG (d, a, b, c, pM[10], S22,  0x2441453); //- 22 -
GG (c, d, a, b, pM[15], S23, 0xd8a1e681); //- 23 -
GG (b, c, d, a, pM[ 4], S24, 0xe7d3fbc8); //- 24 -
GG (a, b, c, d, pM[ 9], S21, 0x21e1cde6); //- 25 -
GG (d, a, b, c, pM[14], S22, 0xc33707d6); //- 26 -
GG (c, d, a, b, pM[ 3], S23, 0xf4d50d87); //- 27 -
GG (b, c, d, a, pM[ 8], S24, 0x455a14ed); //- 28 -
GG (a, b, c, d, pM[13], S21, 0xa9e3e905); //- 29 -
GG (d, a, b, c, pM[ 2], S22, 0xfcefa3f8); //- 30 -
GG (c, d, a, b, pM[ 7], S23, 0x676f02d9); //- 31 -
GG (b, c, d, a, pM[12], S24, 0x8d2a4c8a); //- 32 -

//第三轮--------------------------------->
HH (a, b, c, d, pM[ 5], S31, 0xfffa3942); //- 33 -
HH (d, a, b, c, pM[ 8], S32, 0x8771f681); //- 34 -
HH (c, d, a, b, pM[11], S33, 0x6d9d6122); //- 35 -
HH (b, c, d, a, pM[14], S34, 0xfde5380c); //- 36 -
HH (a, b, c, d, pM[ 1], S31, 0xa4beea44); //- 37 -
HH (d, a, b, c, pM[ 4], S32, 0x4bdecfa9); //- 38 -
HH (c, d, a, b, pM[ 7], S33, 0xf6bb4b60); //- 39 -
HH (b, c, d, a, pM[10], S34, 0xbebfbc70); //- 40 -
HH (a, b, c, d, pM[13], S31, 0x289b7ec6); //- 41 -
HH (d, a, b, c, pM[ 0], S32, 0xeaa127fa); //- 42 -
HH (c, d, a, b, pM[ 3], S33, 0xd4ef3085); //- 43 -
HH (b, c, d, a, pM[ 6], S34,  0x4881d05); //- 44 -
HH (a, b, c, d, pM[ 9], S31, 0xd9d4d039); //- 45 -
HH (d, a, b, c, pM[12], S32, 0xe6db99e5); //- 46 -
HH (c, d, a, b, pM[15], S33, 0x1fa27cf8); //- 47 -
HH (b, c, d, a, pM[ 2], S34, 0xc4ac5665); //- 48 -

//第四轮-------------------------------->
II (a, b, c, d, pM[ 0], S41, 0xf4292244); //- 49 -
II (d, a, b, c, pM[ 7], S42, 0x432aff97); //- 50 -
II (c, d, a, b, pM[14], S43, 0xab9423a7); //- 51 -
II (b, c, d, a, pM[ 5], S44, 0xfc93a039); //- 52 -
II (a, b, c, d, pM[12], S41, 0x655b59c3); //- 53 -
II (d, a, b, c, pM[ 3], S42, 0x8f0ccc92); //- 54 -
II (c, d, a, b, pM[10], S43, 0xffeff47d); //- 55 -
II (b, c, d, a, pM[ 1], S44, 0x85845dd1); //- 56 -
II (a, b, c, d, pM[ 8], S41, 0x6fa87e4f); //- 57 -
II (d, a, b, c, pM[15], S42, 0xfe2ce6e0); //- 58 -
II (c, d, a, b, pM[ 6], S43, 0xa3014314); //- 59 -
II (b, c, d, a, pM[13], S44, 0x4e0811a1); //- 60 -
II (a, b, c, d, pM[ 4], S41, 0xf7537e82); //- 61 -
II (d, a, b, c, pM[11], S42, 0xbd3af235); //- 62 -
II (c, d, a, b, pM[ 2], S43, 0x2ad7d2bb); //- 63 -
II (b, c, d, a, pM[ 9], S44, 0xeb86d391); //- 64 -

T[0]+=a;
T[1]+=b;
T[2]+=c;
T[3]+=d;

return ;
}

LPCSTR CMd5::GetDigestKey()
{
if(IsSuc)
{
return Digest;
}

SetErr(4);

return NULL;
}

bool CMd5::CaculateFile()
{
if(*fname==0)
{
SetErr(2);
return false;
}
if(!OpenFile())
{
SetErr(0);
return false;
}

bool bl;

do
{
bl=Read64Byte();
TransForm();

}while(bl);

JustifytoStr();

return true;
}

bool CMd5::CaculateStr(LPCSTR str)
{
ULONG slen=strlen(str);
ULONG n=slen/64,ntail=slen%64;

for(int i=0;i<n;i++)
{
ULONG *p=(ULONG *)str;
TransForm();
pM+=16;
}

memset(Pointer,0,64);
memcpy(Pointer,str,ntail);
UCHAR *pt=(UCHAR *)Pointer+ntail;
*pt=0x80;
LONG64 *pl=(LONG64 *)Pointer+7;
*pl=(LONG64)(slen*8);
TransForm();
JustifytoStr();

return true;
}

void CMd5::SetErr(int nErr)
{
if(*strErr)
{
return;
}

IsSuc=false;

if(nErr==0)
{
#ifndef ENGLISH
sprintf(strErr,"打不开文件 [ %s ] !/n请确认文件是否存在 !",fname);
#else
sprintf(strErr,"Can not open the file [ %s ] !",fname);
#endif
}
else
{
#ifndef ENGLISH
strcpy(strErr,ErrInfo[nErr][1]);
#else
strcpy(strErr,ErrInfo[nErr][0]);
#endif
}
}

LPCSTR CMd5::GetErr()
{
if(!*strErr)
{
#ifndef ENGLISH
return "未发生错误 !";
#else
return "No error !";
#endif
}
else
{
return strErr;
}
}

void  CMd5::JustifytoStr()
{
char temp[10];

for(int i=0;i<4;i++)
{
T[i]=(T[i]<<24)|((T[i]&0xff00)<<8)|((T[i]&0xff0000)>>8)|(T[i]>>24);

sprintf(temp,"%08x",T[i]);
strcat(Digest,temp);
}
}