JFFS3 & performance

Artem B. Bityuckiy dedekind at infradead.org
Tue Dec 21 09:45:38 EST 2004


Hi, 

> Principle of crc:
> A crc is nothing but the remainder of an integer division.  That
> simple.
>
>
> Example crc4:
> crc4(data) = data%13;
Hmm, is it really correct? CRC is ramainder, but in mod 2 arithmetic. I 
consulted http://www.cs.waikato.ac.nz/~312/crc.txt

And if so, your algorithm
u32 crc24(void *m, size_t len)
{
        u32 ret=0;
        char *s=m;
        size_t i;
        for (i=0; i<len; i++) {
                ret <<= 8;
                ret += s[i];
                ret %/ 0xfffffd
        }
        return ret;
}

doesn't look like something which is called CRC...

Do I misunderstand something?

--
Best Regards,
Artem B. Bityuckiy,
St.-Petersburg, Russia.




More information about the linux-mtd mailing list