Jeff King <peff@xxxxxxxx> writes:
> switch to iterating with a numeric index (as we do in sequencer.c here).
> In other cases (like the cache_end one) the use of an end pointer is
> more natural; we can keep that by just explicitly checking for NULL when
> assigning the end pointer.
>
> diff --git a/xdiff-interface.c b/xdiff-interface.c
> index 8509f9ea22..2f1fe48512 100644
> --- a/xdiff-interface.c
> +++ b/xdiff-interface.c
> @@ -84,8 +84,8 @@ static void trim_common_tail(mmfile_t *a, mmfile_t *b)
> {
> const int blk = 1024;
> long trimmed = 0, recovered = 0;
> - char *ap = a->ptr + a->size;
> - char *bp = b->ptr + b->size;
> + char *ap = a->ptr ? a->ptr + a->size : a->ptr;
> + char *bp = b->ptr ? b->ptr + b->size : b->ptr;
> long smaller = (a->size < b->size) ? a->size : b->size;
>
> while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
Isn't it a bug for a->ptr or b->ptr to be NULL here? Even if we
manage to assign ap = a->ptr = NULL without complaints, how would
that memcmp work?
Is it that the corresponding .size would always be 0 if .ptr is NULL
that protects us?
A bit puzzled.
