bug#8528: 24.0.50; 32-bit Emacs with apparent 128M buffer size limit

[Paul Eggert <eggert@cs.ucla.edu>]

On 04/20/11 23:40, Eli Zaretskii wrote:
> Right, but wouldn't you agree that such a limitation is too stringent?

Yes, absolutely, the limit should be removed if possible.

In a brief look at the code, it appeared to me that there were
places where the it does not check for integer overflow
in size calculations when converting external to internal form.  So
it could well be that this preliminary check may be needed to
avoid catastrophe later.  I have not checked this out carefully,
though, and I could be wrong.  (One way to find out would be
to test it with a worst-case-bloat file, but I haven't had time to
do that.)

> E.g., I should be able to use find-file-literally to visit a 512MB
> file, but currently I cannot.

If we know that byte bloat cannot occur, which is the case with
find-file-literally, then the divide-by-4 limit should not be needed.
That case should be easy, in that it shouldn't require a lot
of analysis to fix that case safely.