Re: CVS commit: src (getdelim.c:1.1)

[Geoff Wing <gcw%pobox.com@localhost>]

On Tuesday 2009-07-14 16:46 +0100, Roy Marples output:
:-              newlen = off + len + 1;
:-              /* Ensure that the resultant buffer length fits in ssize_t */
:-              if (newlen > (size_t)SSIZE_MAX + 1) {
:+              newlen = off + len;
:+              /* Ensure that the resultant buffer length fits in ssize_t. */
:+              if (newlen > SSIZE_MAX) {

I may have explained this poorly.  "newlen", "off" and "len" are
signed numbers.  If the addition "off + len" overflows ssize_t (also signed),
then "newlen" is now negative and will never be greater than SSIZE_MAX.  Yes?

Of course, since the comparison is with SSIZE_MAX (as the maximum of the
signed numbers in that comparison) nothing is greater than it.  Or my
understanding is really wonky.  Ah well, it is 2 a.m. here.

Regards,
Geoff