[Expat-discuss] expat parsing destructively?

[Nick MacDonald]

Mark:

You are of course absolutely correct in that regard... and I don't
know what kind of internal memory management eXpat performs, so this
may well be a very bad idea.  I do know, that in many cases, eXpat
seems to return to you a copy of the same data it is parsing... I just
don't know if it does that in all cases.  You could of course detect
when the returned data did not reside within your supplied buffer,
however its not quite clear to me what action you might take in such a
case.

Nick


On 29 Oct 2007 10:22:46 -0000, Mark <11mjazbdg02 at sneakemail.com> wrote:
> I think this is extremely unlikely this will work.  You are assuming that expat will always return a pointer to the data contained within the original memory buffer and not in any internal buffers.
>
> ---- Original Message ----
> Simply allocate 2 copies of the same data... i.e. read in the data to
> one buffer, malloc() another buffer the same size, and do a huge
> memcpy() to make a duplicate copy.  Now let eXpat scan one copy, and
> doing some quick and dirty pointer math, you can now find
> corresponding locations in the "non-eXpat" buffer and destroy it to
> your hearts content.  When you're all done, simply free both buffers.
> Its a little more memory intensive.. but sounds fairly elegant to me,
> and you don't need to worry about doing anything unsupported by eXpat.