[xml] Question about memory constraints when using SAX parser

[Veiko Sinivee <veiko sinivee solo delfi ee>]

Hi,

I'm writing a digital signature and xml encryption library. I want
to support encryption & decryption of very large files too. Well
encryption goes fine because I read, encrypt, base64 encode and write
data to the file in blocks of 8 KB or so. For decryption I choose to use
the SAX interface because it's probably the fastest and requires the 
least amount of memory. Now I found, that xmlCharaters() callback
function is still called with a lot of data. Earlier versions of libxml2
used to return data in blocks of x KB. Now If I have something like:

<CipherData>
...
700 MB of base64 encoded data here
...
</CipherData

then the parser attempts to collect all of that data and return it
in one event to my callback function. This obviously doesn't work.
How can I switch it out and tell the parser to return at most x KB
in any event ?

regards,

Veiko Sinivee