Re: [PATCH 2/5] http: use `size_t` for byte position in fwrite_sha1_file

[Junio C Hamano <gitster@pobox.com>]

Simon Richter <Simon.Richter@hogyros.de> writes:

>> I agree that changing the type of posn from int to size_t is the
>> right move.
>
> It is a position in a file that is being read as binary data[1], so 
> off_t would be the best choice I think.

Hmm, interesting.  The function writes out eltsize * nmemb (both are
of type size_t) bytes, so the total could theoretically exceed the
range that fits size_t.

But the thing is that posn is used this way

		ssize_t retval = xwrite(freq->localfile,
					(char *) ptr + posn, size - posn);

to offset into a contiguous in-core region that starts at ptr.  I am
not sure if (ptr + posn) is still valid for posn that is too large
to fit in size_t, though.

To put it differently, we are writing out what is in the contiguous
in-core region and posn runs up to the allocation size of that
region, which should be measured in size_t, no?