https://blog.csdn.net/wudishine/article/details/42466831

MD5.h

#ifndef MD5_H
#define MD5_H
 
#include <string>
#include <fstream>
 
/* Type define */
typedef unsigned char byte;
typedef unsigned long ulong;
 
using std::string;
using std::ifstream;
 
/* MD5 declaration. */
class MD5 {
public:
    MD5();
    MD5(const void *input, size_t length);
    MD5(const string &str);
    MD5(ifstream &in);
    void update(const void *input, size_t length);
    void update(const string &str);
    void update(ifstream &in);
    const byte* digest();
    string toString();
    void reset();
private:
    void update(const byte *input, size_t length);
    void final();
    void transform(const byte block[64]);
    void encode(const ulong *input, byte *output, size_t length);
    void decode(const byte *input, ulong *output, size_t length);
    string bytesToHexString(const byte *input, size_t length);
 
    /* class uncopyable */
    MD5(const MD5&);
    MD5& operator=(const MD5&);
private:
    ulong _state[4];    /* state (ABCD) */
    ulong _count[2];    /* number of bits, modulo 2^64 (low-order word first) */
    byte _buffer[64];   /* input buffer */
    byte _digest[16];   /* message digest */
    bool _finished;     /* calculate finished ? */
 
    static const byte PADDING[64];  /* padding for calculate */
    static const char HEX[16];
    static const size_t BUFFER_SIZE = 1024;
};
 
#endif/*MD5_H*/
 

MD5.cpp

#include "md5.h"
 
using namespace std;
 
/* Constants for MD5Transform routine. */
#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
 
 
/* F, G, H and I are basic MD5 functions.
*/
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))
 
/* ROTATE_LEFT rotates x left n bits.
*/
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
 
/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
Rotation is separate from addition to prevent recomputation.
*/
#define FF(a, b, c, d, x, s, ac) {     (a) += F ((b), (c), (d)) + (x) + ac;     (a) = ROTATE_LEFT ((a), (s));     (a) += (b); }
#define GG(a, b, c, d, x, s, ac) {     (a) += G ((b), (c), (d)) + (x) + ac;     (a) = ROTATE_LEFT ((a), (s));     (a) += (b); }
#define HH(a, b, c, d, x, s, ac) {     (a) += H ((b), (c), (d)) + (x) + ac;     (a) = ROTATE_LEFT ((a), (s));     (a) += (b); }
#define II(a, b, c, d, x, s, ac) {     (a) += I ((b), (c), (d)) + (x) + ac;     (a) = ROTATE_LEFT ((a), (s));     (a) += (b); }
 
 
const byte MD5::PADDING[64] = { 0x80 };
const char MD5::HEX[16] = {
    ‘0‘, ‘1‘, ‘2‘, ‘3‘,
    ‘4‘, ‘5‘, ‘6‘, ‘7‘,
    ‘8‘, ‘9‘, ‘a‘, ‘b‘,
    ‘c‘, ‘d‘, ‘e‘, ‘f‘
};
 
/* Default construct. */
MD5::MD5() {
    reset();
}
 
/* Construct a MD5 object with a input buffer. */
MD5::MD5(const void *input, size_t length) {
    reset();
    update(input, length);
}
 
/* Construct a MD5 object with a string. */
MD5::MD5(const string &str) {
    reset();
    update(str);
}
 
/* Construct a MD5 object with a file. */
MD5::MD5(ifstream &in) {
    reset();
    update(in);
}
 
/* Return the message-digest */
const byte* MD5::digest() {
    if (!_finished) {
        _finished = true;
        final();
    }
    return _digest;
}
 
/* Reset the calculate state */
void MD5::reset() {
 
    _finished = false;
    /* reset number of bits. */
    _count[0] = _count[1] = 0;
    /* Load magic initialization constants. */
    _state[0] = 0x67452301;
    _state[1] = 0xefcdab89;
    _state[2] = 0x98badcfe;
    _state[3] = 0x10325476;
}
 
/* Updating the context with a input buffer. */
void MD5::update(const void *input, size_t length) {
    update((const byte*)input, length);
}
 
/* Updating the context with a string. */
void MD5::update(const string &str) {
    update((const byte*)str.c_str(), str.length());
}
 
/* Updating the context with a file. */
void MD5::update(ifstream &in) {
 
    if (!in)
        return;
 
    std::streamsize length;
    char buffer[BUFFER_SIZE];
    while (!in.eof()) {
        in.read(buffer, BUFFER_SIZE);
        length = in.gcount();
        if (length > 0)
            update(buffer, length);
    }
    in.close();
}
 
/* MD5 block update operation. Continues an MD5 message-digest
operation, processing another message block, and updating the
context.
*/
void MD5::update(const byte *input, size_t length) {
 
    ulong i, index, partLen;
 
    _finished = false;
 
    /* Compute number of bytes mod 64 */
    index = (ulong)((_count[0] >> 3) & 0x3f);
 
    /* update number of bits */
    if((_count[0] += ((ulong)length << 3)) < ((ulong)length << 3))
        _count[1]++;
    _count[1] += ((ulong)length >> 29);
 
    partLen = 64 - index;
 
    /* transform as many times as possible. */
    if(length >= partLen) {
 
        memcpy(&_buffer[index], input, partLen);
        transform(_buffer);
 
        for (i = partLen; i + 63 < length; i += 64)
            transform(&input[i]);
        index = 0;
 
    } else {
        i = 0;
    }
 
    /* Buffer remaining input */
    memcpy(&_buffer[index], &input[i], length-i);
}
 
/* MD5 finalization. Ends an MD5 message-_digest operation, writing the
the message _digest and zeroizing the context.
*/
void MD5::final() {
 
    byte bits[8];
    ulong oldState[4];
    ulong oldCount[2];
    ulong index, padLen;
 
    /* Save current state and count. */
    memcpy(oldState, _state, 16);
    memcpy(oldCount, _count, 8);
 
    /* Save number of bits */
    encode(_count, bits, 8);
 
    /* Pad out to 56 mod 64. */
    index = (ulong)((_count[0] >> 3) & 0x3f);
    padLen = (index < 56) ? (56 - index) : (120 - index);
    update(PADDING, padLen);
 
    /* Append length (before padding) */
    update(bits, 8);
 
    /* Store state in digest */
    encode(_state, _digest, 16);
 
    /* Restore current state and count. */
    memcpy(_state, oldState, 16);
    memcpy(_count, oldCount, 8);
}
 
/* MD5 basic transformation. Transforms _state based on block. */
void MD5::transform(const byte block[64]) {
 
    ulong a = _state[0], b = _state[1], c = _state[2], d = _state[3], x[16];
 
    decode(block, x, 64);
 
    /* Round 1 */
    FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
    FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
    FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
    FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
    FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
    FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
    FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
    FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
    FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
    FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
    FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
    FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
    FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
    FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
    FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
    FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */
 
    /* Round 2 */
    GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
    GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
    GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
    GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
    GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
    GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
    GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
    GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
    GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
    GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
    GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
    GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
    GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
    GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
    GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
    GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */
 
    /* Round 3 */
    HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
    HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
    HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
    HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
    HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
    HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
    HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
    HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
    HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
    HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
    HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
    HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
    HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
    HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
    HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
    HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */
 
    /* Round 4 */
    II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
    II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
    II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
    II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
    II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
    II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
    II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
    II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
    II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
    II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
    II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
    II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
    II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
    II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
    II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
    II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */
 
    _state[0] += a;
    _state[1] += b;
    _state[2] += c;
    _state[3] += d;
}
 
/* Encodes input (ulong) into output (byte). Assumes length is
a multiple of 4.
*/
void MD5::encode(const ulong *input, byte *output, size_t length) {
 
    for(size_t i=0, j=0; j<length; i++, j+=4) {
        output[j]= (byte)(input[i] & 0xff);
        output[j+1] = (byte)((input[i] >> 8) & 0xff);
        output[j+2] = (byte)((input[i] >> 16) & 0xff);
        output[j+3] = (byte)((input[i] >> 24) & 0xff);
    }
}
 
/* Decodes input (byte) into output (ulong). Assumes length is
a multiple of 4.
*/
void MD5::decode(const byte *input, ulong *output, size_t length) {
 
    for(size_t i=0, j=0; j<length; i++, j+=4) { 
        output[i] = ((ulong)input[j]) | (((ulong)input[j+1]) << 8) |
            (((ulong)input[j+2]) << 16) | (((ulong)input[j+3]) << 24);
    }
}
 
/* Convert byte array to hex string. */
string MD5::bytesToHexString(const byte *input, size_t length) {
    string str;
    str.reserve(length << 1);
    for(size_t i = 0; i < length; i++) {
        int t = input[i];
        int a = t / 16;
        int b = t % 16;
        str.append(1, HEX[a]);
        str.append(1, HEX[b]);
    }
    return str;
}
 
/* Convert digest to string value */
string MD5::toString() {
    return bytesToHexString(digest(), 16);
}
 

調用

        std::string strMD5;
    std::ifstream f1(filename, std::ios::in | std::ios::binary);
    if (!f1.is_open())
    {
        f1.close();
        //std::cerr << "cannot open input file: " << filename << std::endl;
        return strMD5;
    }

    MD5 md5;
    /*
    std::streamsize length;
    char buffer[1024];
    while (!f1.eof()) {  
        f1.read(buffer, 1024); //extraction 1024
        length = f1.gcount();// get count from last extraction
        if (length > 0)
            md5.update(buffer, length);//每次extraction 1024 bytes，更新到md5中，直到結束
    }
        f1.close();
        */

    md5.update(f1);  //這個函數中已經f1.close()
    strMD5 = md5.toString();
 

===========

Poco庫 獲取文件MD5

#include "MD5Engine.h"

load lib

調用

std::string strMD5;

std::ifstream f1(filename, std::ios::in | std::ios::binary);
if (!f1.is_open())
{
    f1.close();
    //std::cerr << "cannot open input file: " << filename << std::endl;
    return strMD5;
}

Poco::MD5Engine md5;
std::streamsize length;
char buffer[1024000];//char buffer[1024]; 文件太小取，浪費時間，一次1024KB(1MB)的取，速度快 

OutputDebugStringA(std::to_string(sizeof(buffer)).c_str());
OutputDebugStringA("sizeof>>");

UINT countTime(0);
while (!f1.eof()) {
    countTime++;
    OutputDebugStringA(std::to_string(countTime).c_str());
    
    f1.read(buffer, sizeof(buffer)); //extraction
    length = f1.gcount();// get count from last extraction
    if (length > 0)
        md5.update(buffer, length);//extraction buffer，update to md5 buffer，until the end
}



strMD5 = Poco::DigestEngine::digestToHex(md5.digest());

其他

update ( ifstream& ifs);

MD5 校驗文件