On Sun, Oct 14, 2018 at 03:16:36AM +0100, Ramsay Jones wrote:
> diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
> index b059b86aee..3b5f2c38b3 100644
> --- a/builtin/pack-objects.c
> +++ b/builtin/pack-objects.c
> @@ -269,12 +269,12 @@ static void copy_pack_data(struct hashfile *f,
> off_t len)
> {
> unsigned char *in;
> - unsigned long avail;
> + size_t avail;
>
> while (len) {
> in = use_pack(p, w_curs, offset, &avail);
> if (avail > len)
> - avail = (unsigned long)len;
> + avail = xsize_t(len);
We don't actually care about truncation here. The idea is that we take a
bite-sized chunk via use_pack, and loop as necessary. So mod-2^32
truncation via a cast would be bad (we might not make forward progress),
but truncating to SIZE_MAX would be fine.
That said, we know that would not truncate here, because we must
strictly be shrinking "avail", which was already a size_t (unless "len"
is negative, but then we are really screwed ;) ).
So I kind of wonder if a comment would be better than xsize_t here.
Something like:
if (avail > len) {
/*
* This can never truncate because we know that len is smaller
* than avail, which is already a size_t.
*/
avail = (size_t)len;
}
-Peff
