【c++】文件的md5码

MyMd5.h

#pragma once  


/* typedef a 32 bit type */  
typedef unsigned long int UINT4;  

/* Data structure for MD5 (Message Digest) computation */  
typedef struct {  
	UINT4 i[2];                   /* number of _bits_ handled mod 2^64 */  
	UINT4 buf[4];                                    /* scratch buffer */  
	unsigned char in[64];                              /* input buffer */  
	unsigned char digest[16];     /* actual digest after MD5Final call */  
} MD5_CTX;  

void MD5Init(MD5_CTX *mdContext);  
void MD5Update(MD5_CTX *mdContext, unsigned char *inBuf, unsigned int inLen);  
void MD5Final(MD5_CTX *mdContext);  
static void Transform(UINT4 *buf, UINT4 *in);  
char *MD5_file(char *path, int md5_len);  

MyMd5.cpp

#include "MyMd5.h"  
#include <stdlib.h>  
#include <string.h>  
#include <iostream>
  
  
/* forward declaration */  
static void Transform();  
  
static unsigned char PADDING[64] = {  
    0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00  
};  
  
/* F, G and H are basic MD5 functions: selection, majority, parity */  
#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) + (UINT4)(ac);  (a) = ROTATE_LEFT ((a), (s));  (a) += (b);}  
#define GG(a, b, c, d, x, s, ac) {(a) += G ((b), (c), (d)) + (x) + (UINT4)(ac); (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }  
#define HH(a, b, c, d, x, s, ac) {(a) += H ((b), (c), (d)) + (x) + (UINT4)(ac); (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }  
#define II(a, b, c, d, x, s, ac) {(a) += I ((b), (c), (d)) + (x) + (UINT4)(ac); (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }  
  
void MD5Init(MD5_CTX *mdContext)  
{  
    mdContext->i[0] = mdContext->i[1] = (UINT4)0;  
  
    /* Load magic initialization constants.  
    */  
    mdContext->buf[0] = (UINT4)0x67452301;  
    mdContext->buf[1] = (UINT4)0xefcdab89;  
    mdContext->buf[2] = (UINT4)0x98badcfe;  
    mdContext->buf[3] = (UINT4)0x10325476;  
}  
  
void MD5Update(MD5_CTX *mdContext, unsigned char *inBuf, unsigned int inLen)  
{  
    UINT4 in[16];  
    int mdi;  
    unsigned int i, ii;  
  
    /* compute number of bytes mod 64 */  
    mdi = (int)((mdContext->i[0] >> 3) & 0x3F);  
  
    /* update number of bits */  
    if ((mdContext->i[0] + ((UINT4)inLen << 3)) < mdContext->i[0])  
        mdContext->i[1]++;  
    mdContext->i[0] += ((UINT4)inLen << 3);  
    mdContext->i[1] += ((UINT4)inLen >> 29);  
  
    while (inLen--) {  
        /* add new character to buffer, increment mdi */  
        mdContext->in[mdi++] = *inBuf++;  
  
        /* transform if necessary */  
        if (mdi == 0x40) {  
            for (i = 0, ii = 0; i < 16; i++, ii += 4)  
                in[i] = (((UINT4)mdContext->in[ii + 3]) << 24) |  
                (((UINT4)mdContext->in[ii + 2]) << 16) |  
                (((UINT4)mdContext->in[ii + 1]) << 8) |  
                ((UINT4)mdContext->in[ii]);  
            Transform(mdContext->buf, in);  
            mdi = 0;  
        }  
    }  
}  
  
void MD5Final(MD5_CTX *mdContext)  
  
{  
    UINT4 in[16];  
    int mdi;  
    unsigned int i, ii;  
    unsigned int padLen;  
  
    /* save number of bits */  
    in[14] = mdContext->i[0];  
    in[15] = mdContext->i[1];  
  
    /* compute number of bytes mod 64 */  
    mdi = (int)((mdContext->i[0] >> 3) & 0x3F);  
  
    /* pad out to 56 mod 64 */  
    padLen = (mdi < 56) ? (56 - mdi) : (120 - mdi);  
    MD5Update(mdContext, PADDING, padLen);  
  
    /* append length in bits and transform */  
    for (i = 0, ii = 0; i < 14; i++, ii += 4)  
        in[i] = (((UINT4)mdContext->in[ii + 3]) << 24) |  
        (((UINT4)mdContext->in[ii + 2]) << 16) |  
        (((UINT4)mdContext->in[ii + 1]) << 8) |  
        ((UINT4)mdContext->in[ii]);  
    Transform(mdContext->buf, in);  
  
    /* store buffer in digest */  
    for (i = 0, ii = 0; i < 4; i++, ii += 4) {  
        mdContext->digest[ii] = (unsigned char)(mdContext->buf[i] & 0xFF);  
        mdContext->digest[ii + 1] =  
            (unsigned char)((mdContext->buf[i] >> 8) & 0xFF);  
        mdContext->digest[ii + 2] =  
            (unsigned char)((mdContext->buf[i] >> 16) & 0xFF);  
        mdContext->digest[ii + 3] =  
            (unsigned char)((mdContext->buf[i] >> 24) & 0xFF);  
    }  
}  
  
/* Basic MD5 step. Transform buf based on in.  
*/  
static void Transform(UINT4 *buf, UINT4 *in)  
{  
    UINT4 a = buf[0], b = buf[1], c = buf[2], d = buf[3];  
  
    /* Round 1 */  
#define S11 7  
#define S12 12  
#define S13 17  
#define S14 22  
    FF(a, b, c, d, in[0], S11, 3614090360); /* 1 */  
    FF(d, a, b, c, in[1], S12, 3905402710); /* 2 */  
    FF(c, d, a, b, in[2], S13, 606105819); /* 3 */  
    FF(b, c, d, a, in[3], S14, 3250441966); /* 4 */  
    FF(a, b, c, d, in[4], S11, 4118548399); /* 5 */  
    FF(d, a, b, c, in[5], S12, 1200080426); /* 6 */  
    FF(c, d, a, b, in[6], S13, 2821735955); /* 7 */  
    FF(b, c, d, a, in[7], S14, 4249261313); /* 8 */  
    FF(a, b, c, d, in[8], S11, 1770035416); /* 9 */  
    FF(d, a, b, c, in[9], S12, 2336552879); /* 10 */  
    FF(c, d, a, b, in[10], S13, 4294925233); /* 11 */  
    FF(b, c, d, a, in[11], S14, 2304563134); /* 12 */  
    FF(a, b, c, d, in[12], S11, 1804603682); /* 13 */  
    FF(d, a, b, c, in[13], S12, 4254626195); /* 14 */  
    FF(c, d, a, b, in[14], S13, 2792965006); /* 15 */  
    FF(b, c, d, a, in[15], S14, 1236535329); /* 16 */  
  
    /* Round 2 */  
#define S21 5  
#define S22 9  
#define S23 14  
#define S24 20  
    GG(a, b, c, d, in[1], S21, 4129170786); /* 17 */  
    GG(d, a, b, c, in[6], S22, 3225465664); /* 18 */  
    GG(c, d, a, b, in[11], S23, 643717713); /* 19 */  
    GG(b, c, d, a, in[0], S24, 3921069994); /* 20 */  
    GG(a, b, c, d, in[5], S21, 3593408605); /* 21 */  
    GG(d, a, b, c, in[10], S22, 38016083); /* 22 */  
    GG(c, d, a, b, in[15], S23, 3634488961); /* 23 */  
    GG(b, c, d, a, in[4], S24, 3889429448); /* 24 */  
    GG(a, b, c, d, in[9], S21, 568446438); /* 25 */  
    GG(d, a, b, c, in[14], S22, 3275163606); /* 26 */  
    GG(c, d, a, b, in[3], S23, 4107603335); /* 27 */  
    GG(b, c, d, a, in[8], S24, 1163531501); /* 28 */  
    GG(a, b, c, d, in[13], S21, 2850285829); /* 29 */  
    GG(d, a, b, c, in[2], S22, 4243563512); /* 30 */  
    GG(c, d, a, b, in[7], S23, 1735328473); /* 31 */  
    GG(b, c, d, a, in[12], S24, 2368359562); /* 32 */  
  
    /* Round 3 */  
#define S31 4  
#define S32 11  
#define S33 16  
#define S34 23  
    HH(a, b, c, d, in[5], S31, 4294588738); /* 33 */  
    HH(d, a, b, c, in[8], S32, 2272392833); /* 34 */  
    HH(c, d, a, b, in[11], S33, 1839030562); /* 35 */  
    HH(b, c, d, a, in[14], S34, 4259657740); /* 36 */  
    HH(a, b, c, d, in[1], S31, 2763975236); /* 37 */  
    HH(d, a, b, c, in[4], S32, 1272893353); /* 38 */  
    HH(c, d, a, b, in[7], S33, 4139469664); /* 39 */  
    HH(b, c, d, a, in[10], S34, 3200236656); /* 40 */  
    HH(a, b, c, d, in[13], S31, 681279174); /* 41 */  
    HH(d, a, b, c, in[0], S32, 3936430074); /* 42 */  
    HH(c, d, a, b, in[3], S33, 3572445317); /* 43 */  
    HH(b, c, d, a, in[6], S34, 76029189); /* 44 */  
    HH(a, b, c, d, in[9], S31, 3654602809); /* 45 */  
    HH(d, a, b, c, in[12], S32, 3873151461); /* 46 */  
    HH(c, d, a, b, in[15], S33, 530742520); /* 47 */  
    HH(b, c, d, a, in[2], S34, 3299628645); /* 48 */  
  
    /* Round 4 */  
#define S41 6  
#define S42 10  
#define S43 15  
#define S44 21  
    II(a, b, c, d, in[0], S41, 4096336452); /* 49 */  
    II(d, a, b, c, in[7], S42, 1126891415); /* 50 */  
    II(c, d, a, b, in[14], S43, 2878612391); /* 51 */  
    II(b, c, d, a, in[5], S44, 4237533241); /* 52 */  
    II(a, b, c, d, in[12], S41, 1700485571); /* 53 */  
    II(d, a, b, c, in[3], S42, 2399980690); /* 54 */  
    II(c, d, a, b, in[10], S43, 4293915773); /* 55 */  
    II(b, c, d, a, in[1], S44, 2240044497); /* 56 */  
    II(a, b, c, d, in[8], S41, 1873313359); /* 57 */  
    II(d, a, b, c, in[15], S42, 4264355552); /* 58 */  
    II(c, d, a, b, in[6], S43, 2734768916); /* 59 */  
    II(b, c, d, a, in[13], S44, 1309151649); /* 60 */  
    II(a, b, c, d, in[4], S41, 4149444226); /* 61 */  
    II(d, a, b, c, in[11], S42, 3174756917); /* 62 */  
    II(c, d, a, b, in[2], S43, 718787259); /* 63 */  
    II(b, c, d, a, in[9], S44, 3951481745); /* 64 */  
  
    buf[0] += a;  
    buf[1] += b;  
    buf[2] += c;  
    buf[3] += d;  
}  
  
  
char *MD5_file(char *path, int md5_len)  
{  
    FILE *fp = fopen(path, "rb");  
    MD5_CTX mdContext;  
    int bytes;  
    unsigned char data[1024];  
    char *file_md5;  
    int i;  
  
    if (fp == NULL) {  
        fprintf(stderr, "fopen %s failed\n", path);  
        return NULL;  
    }  
  
    MD5Init(&mdContext);  
    while ((bytes = fread(data, 1, 1024, fp)) != 0)  
    {  
        MD5Update(&mdContext, data, bytes);  
    }  
    MD5Final(&mdContext);  
  
    file_md5 = (char *)malloc((md5_len + 1) * sizeof(char));  
    if (file_md5 == NULL)  
    {  
        fprintf(stderr, "malloc failed.\n");  
        return NULL;  
    }  
    memset(file_md5, 0, (md5_len + 1));  
  
    if (md5_len == 16)  
    {  
        for (i = 4; i < 12; i++)  
        {  
            sprintf(&file_md5[(i - 4) * 2], "%02x", mdContext.digest[i]);  
        }  
    }  
    else if (md5_len == 32)  
    {  
        for (i = 0; i < 16; i++)  
        {  
            sprintf(&file_md5[i * 2], "%02x", mdContext.digest[i]);  
        }  
    }  
    else  
    {  
        fclose(fp);  
        free(file_md5);  
        return NULL;  
    }  
  
    fclose(fp);  
    return file_md5;  
}  

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转载自blog.csdn.net/qq_15947787/article/details/80487998