Method getHashFromFile

depends/md5/md5wrapper.cpp:103–157

* creates a MD5 hash from * a file specified in "filename" and * returns it as string * (based on Ronald L. Rivest's code * from RFC1321 "The MD5 Message-Digest Algorithm") */

 * from RFC1321 "The MD5 Message-Digest Algorithm")
 */
std::string md5wrapper::getHashFromFile(std::string filename, uint32_t & length, char * first_kb)
{
    FILE *file;
    MD5Context context;

    int len;
    int saved = 0;
    unsigned char buffer[1024], digest[16];

    //open file
    if ((file = fopen (filename.c_str(), "rb")) == NULL)
    {
        return "file unreadable.";
    }
    length = 0;
    //init md5
    MD5Init (&context);

    //read the filecontent
    while (1)
    {
        errno = 0;
        len = fread (buffer, 1, 1024, file);
        if(saved < 1024 && first_kb)
        {
            memcpy(first_kb + saved, buffer, std::min (len, 1024 - saved));
            saved += len;
        }
        length += len;
        if(len != 1024)
        {
            int err = ferror(file);
            //FIXME: check errno here.
            if(err)
            {
                fclose(file);
                return strerror(err);
            }
            if(feof(file))
            {
                MD5Update (&context, buffer, len);
                break;
            }
        }
        MD5Update (&context, buffer, len);
    }

    /*
    generate hash, close the file and return the
    hash as std::string
    */
    MD5Final (digest, &context);
    fclose (file);
    return convToString(digest);
 }

/*
 * EOF