Ich weiss, solche Fehler wurde hier bestimmt schon oft diskutiert, aber ich bekomme es dennoch nicht hin.

Also ich habe folgende Klasse:

// cMD5.h: interface for the cMD5 class.

#if !defined(AFX_CMD5_H__6C2F7C61_93D8_11D8_A8BA_000AE637F271__INCLUDED_)
#define AFX_CMD5_H__6C2F7C61_93D8_11D8_A8BA_000AE637F271__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#define _ReadBufSize 1000000

class cMD5  
{
public:
    char* CalcMD5FromString(const char *s8_Input);
    char* CalcMD5FromFile  (const char *s8_Path);

    void FreeBuffer();
    cMD5();
    virtual ~cMD5();

private:
    struct MD5Context 
    {
        unsigned long buf[4];
        unsigned long bits[2];
        unsigned char in[64];
    };

    void MD5Init();
    void MD5Update(unsigned char *buf, unsigned len);
    void MD5Final (unsigned char digest[16]);

    void MD5Transform(unsigned long buf[4], unsigned long in[16]);
    char* MD5FinalToString();

    void byteReverse (unsigned char *buf, unsigned longs);

    char *mp_s8ReadBuffer;
    MD5Context ctx;
    char   ms8_MD5[40]; // Output buffer
};

#endif // !defined(AFX_CMD5_H__6C2F7C61_93D8_11D8_A8BA_000AE637F271__INCLUDED_)

#include "cMD5.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

cMD5::cMD5()
{
    // don't alloc buffer here, only on request
    mp_s8ReadBuffer = 0;
}

cMD5::~cMD5()
{
    FreeBuffer();
}

void cMD5::FreeBuffer()
{
    if (mp_s8ReadBuffer) delete mp_s8ReadBuffer;
}

/*********************************************************************
//
//         calculate MD5 from a file of any size (also size = 0)
//         returns "" on file error
//
/********************************************************************/

char* cMD5::CalcMD5FromFile(const char *s8_Path)
{
    if (!mp_s8ReadBuffer) mp_s8ReadBuffer = new char[_ReadBufSize];

    MD5Init();

    // ++++++++++++ Read file block by block +++++++++++

    HANDLE h_File = CreateFile(s8_Path, GENERIC_READ, FILE_SHARE_READ, 0, 
                               OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

    if (h_File == INVALID_HANDLE_VALUE)
        return "";

    int s32_Size = GetFileSize(h_File, 0);

    while (s32_Size > 0)
    {
        unsigned long u32_Read = 0;
        if (!ReadFile(h_File, mp_s8ReadBuffer, _ReadBufSize, &u32_Read, 0))
        {
            CloseHandle(h_File);
            return "";
        }

        MD5Update((unsigned char*)mp_s8ReadBuffer, u32_Read);

        s32_Size -= u32_Read;
    };

    CloseHandle(h_File);

    // ++++++++++++ Signature --> String +++++++++++

    return MD5FinalToString();
}

/*********************************************************************
//
//                calculate MD5 from a string
//
/********************************************************************/

char* cMD5::CalcMD5FromString(const char *s8_Input)
{
    MD5Init();
    MD5Update((unsigned char*)s8_Input, strlen(s8_Input));

    return MD5FinalToString();
}

/*********************************************************************
//
//                           Calculation functions
//
/*********************************************************************
/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
void cMD5::MD5Init()
{
    ctx.buf[0] = 0x67452301;
    ctx.buf[1] = 0xefcdab89;
    ctx.buf[2] = 0x98badcfe;
    ctx.buf[3] = 0x10325476;

    ctx.bits[0] = 0;
    ctx.bits[1] = 0;
}

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
void cMD5::MD5Update(unsigned char *buf, unsigned len)
{
    unsigned long t;

    /* Update bitcount */

    t = ctx.bits[0];
    if ((ctx.bits[0] = t + ((unsigned long) len << 3)) < t)
    ctx.bits[1]++;  /* Carry from low to high */
    ctx.bits[1] += len >> 29;

    t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */

    /* Handle any leading odd-sized chunks */

    if (t) {
    unsigned char *p = (unsigned char *) ctx.in + t;

    t = 64 - t;
    if (len < t) {
        memcpy(p, buf, len);
        return;
    }
    memcpy(p, buf, t);
    cMD5::byteReverse(ctx.in, 16);
    MD5Transform(ctx.buf, (unsigned long *) ctx.in);
    buf += t;
    len -= t;
    }
    /* Process data in 64-byte chunks */

    while (len >= 64) {
    memcpy(ctx.in, buf, 64);
    cMD5::byteReverse(ctx.in, 16);
    MD5Transform(ctx.buf, (unsigned long *) ctx.in);
    buf += 64;
    len -= 64;
    }

    /* Handle any remaining bytes of data. */

    memcpy(ctx.in, buf, len);
}

/*
 * Convert signature to CString
 */
char* cMD5::MD5FinalToString()
{
    unsigned char signature[16];
    MD5Final(signature);

    ms8_MD5[0] = 0;
    char s8_Temp[5];
    for (int i=0; i<16; i++) 
    {
        sprintf(s8_Temp, "%02X", signature[i]);
        strcat(ms8_MD5, s8_Temp);
    }

    return ms8_MD5;
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern 
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
void cMD5::MD5Final(unsigned char digest[16])
{
    unsigned count;
    unsigned char *p;

    /* Compute number of bytes mod 64 */
    count = (ctx.bits[0] >> 3) & 0x3F;

    /* Set the first char of padding to 0x80.  This is safe since there is
       always at least one byte free */
    p = ctx.in + count;
    *p++ = 0x80;

    /* Bytes of padding needed to make 64 bytes */
    count = 64 - 1 - count;

    /* Pad out to 56 mod 64 */
    if (count < 8) {
    /* Two lots of padding:  Pad the first block to 64 bytes */
    memset(p, 0, count);
    cMD5::byteReverse(ctx.in, 16);
    MD5Transform(ctx.buf, (unsigned long *) ctx.in);

    /* Now fill the next block with 56 bytes */
    memset(ctx.in, 0, 56);
    } else {
    /* Pad block to 56 bytes */
    memset(p, 0, count - 8);
    }
    cMD5::byteReverse(ctx.in, 14);

    /* Append length in bits and transform */
    ((unsigned long *) ctx.in)[14] = ctx.bits[0];
    ((unsigned long *) ctx.in)[15] = ctx.bits[1];

    MD5Transform(ctx.buf, (unsigned long *) ctx.in);
    cMD5::byteReverse((unsigned char *) ctx.buf, 4);
    memcpy(digest, ctx.buf, 16);
    memset(&ctx, 0, sizeof(MD5Context));        /* In case it's sensitive */
}

/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
    ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
void cMD5::MD5Transform(unsigned long buf[4], unsigned long in[16])
{
    register unsigned long a, b, c, d;

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

    MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
    MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
    MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
    MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
    MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
    MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
    MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
    MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
    MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
    MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
    MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
    MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
    MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
    MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
    MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
    MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

    MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
    MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
    MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
    MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
    MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
    MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
    MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
    MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
    MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
    MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
    MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
    MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
    MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
    MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
    MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
    MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

    MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
    MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
    MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
    MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
    MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
    MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
    MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
    MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
    MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
    MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
    MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
    MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
    MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
    MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
    MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
    MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

    MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
    MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
    MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
    MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
    MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
    MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
    MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
    MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
    MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
    MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
    MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
    MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
    MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
    MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
    MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
    MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

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

#ifdef sgi
#define HIGHFIRST
#endif

#ifdef sun
#define HIGHFIRST
#endif

#ifndef HIGHFIRST
    void cMD5::byteReverse(unsigned char *buf, unsigned longs)  
    {
        // Nothing
    }
#else
    // Note: this code is harmless on little-endian machines.
    void cMD5::byteReverse(unsigned char *buf, unsigned longs)
    {
        unsigned long t;
        do {
        t = (unsigned long) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
            ((unsigned) buf[1] << 8 | buf[0]);
        *(unsigned long *) buf = t;
        buf += 4;
        } while (--longs);
    }
#endif

Wenn ich das versuche mit VS2008 zu kompilieren:

#include "cMD5.h"

int main()
{
  cMD5 test;
  return 0;
}

Bekomme ich folgende Linker-Fehler:

Error 1 error LNK2019: unresolved external symbol "public: virtual __thiscall cMD5::~cMD5(void)" (??1cMD5@@UAE@XZ) referenced in function _main main.obj asd

Error 2 error LNK2019: unresolved external symbol "public: __thiscall cMD5::cMD5(void)" (??0cMD5@@QAE@XZ) referenced in function _main main.obj asd

Ich wüsste nicht, auf welche Datei(en) man da linken muss.

Kann mir jemand sagen, wie man das beheben kann?

Vielen Dank

Simon

Ich vermute, dass cMD5.cpp nicht im Projekt ist, deshalb nicht kompiliert wird und deshalb das linken fehlschlägt.

Simon

Man bin ich blöd
Danke