Re: Strange interval arithmetic

[Michael Fuhr <mike(at)fuhr(dot)org>]

On Wed, Nov 30, 2005 at 02:01:46PM -0500, Tom Lane wrote:
> Michael Fuhr <mike(at)fuhr(dot)org> writes:
> > Any preferences on an approach?  The simplest and easiest to verify
> > would be to raise an error for just this particular case; a TODO
> > item might be to change how the string is parsed to allow values
> > larger than LONG_MAX.
> 
> I think the latter would be a feature enhancement and therefore not
> good material to back-patch.  Just erroring out seems appropriate
> for now.

Agreed.  I'm thinking about rewriting strtol() calls in datetime.c
to look like this:

  errno = 0;
  val = strtol(field[i], &cp, 10);
  if (errno == ERANGE)
      return DTERR_FIELD_OVERFLOW;

Does that look okay?  Or would you rather raise an error with ereport()?

> > I see several calls to strtol() that aren't checked for overflow but
> > that might not be relevant to this problem, so I'm thinking this patch
> > ought not touch them.  Maybe that's another TODO item.
> 
> If it's possible for them to be given overflowing input, they probably
> ought to be checked.

I'm looking at all the strtol() calls in datetime.c right now; I
haven't looked anywhere else yet.  Should I bother checking values
that will be range checked later anyway?  Time zone displacements,
for example?

-- 
Michael Fuhr