md5获取方法(c语言)

来源：互联网发布：c语言标志变量编辑：程序博客网时间：2024/06/06 03:06

#include <openssl/md5.h>
#include <unistd.h>
int main()
{
        int n;
        MD5_CTX c;
        char buf[512];
        ssize_t bytes;
        unsigned char out[MD5_DIGEST_LENGTH];

        MD5_Init(&c);
        bytes=read(STDIN_FILENO, buf, 512);
        while(bytes > 0)
        {
                MD5_Update(&c, buf, bytes);
                bytes=read(STDIN_FILENO, buf, 512);
        }

        MD5_Final(out, &c);

        for(n=0; n<MD5_DIGEST_LENGTH; n++)
                printf("%02x", out[n]);
        printf("\n");

        return(0);
}

#include <stdio.h>
#include <ctype.h>

#define STR_VALUE(val) #val
#define STR(name) STR_VALUE(name)

#define PATH_LEN 256
#define MD5_LEN 32

int CalcFileMD5(char *file_name, char *md5_sum)
{
    #define MD5SUM_CMD_FMT "md5sum %." STR(PATH_LEN) "s 2>/dev/null"
    char cmd[PATH_LEN + sizeof (MD5SUM_CMD_FMT)];
    sprintf(cmd, MD5SUM_CMD_FMT, file_name);
    #undef MD5SUM_CMD_FMT

    FILE *p = popen(cmd, "r");
    if (p == NULL) return 0;

    int i, ch;
    for (i = 0; i < MD5_LEN && isxdigit(ch = fgetc(p)); i++) {
        *md5_sum++ = ch;
    }

    *md5_sum = '\0';
    pclose(p);
    return i == MD5_LEN;
}

int main(int argc, char *argv[])
{
    char md5[MD5_LEN + 1];

    if (!CalcFileMD5("~/testfile", md5)) {
        puts("Error occured!");
    } else {
        printf("Success! MD5 sum is: %s\n", md5);
    }
}

http://www.cplusplus.com/forum/unices/3929/
http://www.abgba.com/article/Technology/C-FileMD5-Calculator.html
http://www.ibm.com/developerworks/cn/linux/l-openssl.html
http://www.openssl.org/docs/apps/openssl.html