[U-Boot] [PATCH v2] lib:crc32: Allow setting of the initial crc32 value

Wolfgang Denk wd at denx.de
Wed May 7 12:42:40 CEST 2014


Dear Lukasz Majewski,

In message <1399443021-11748-1-git-send-email-l.majewski at samsung.com> you wrote:
> The current approach set the initial value of crc32 calculation to zero,
> which is correct for calculating checksum of the whole chunk of data.
... 
> +	if (*output)
> +		memcpy(&crc, output, sizeof(crc));
> +
> +	crc = crc32_wd(crc, input, ilen, chunk_sz);
>  	crc = htonl(crc);
>  	memcpy(output, &crc, sizeof(crc));

You can actually remove the "if (*output)" because output has always
to be a non-null pointer, as we're going to store the result there.

Which means that you cannot use this to implicitly initialize crc =0,
whichin turn means you MUST add porper initialization to all callers
of that function.

Best regards,

Wolfgang Denk

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