Deflater: is it possible to clone state (or rollback)?

Question

Suppose I'm using a Deflater to compress a stream of bytes, and at some intervals I have the option of feeding it with two different byte arrays (two alternative representations of the same info), so that I can choose the most compressible one. Ideally, I would like to be able to clone the state of a "live" deflater, so that I can feed each instance with an array, check the results, and discard the undesirable one. Alternatively, I'd like to mark the current state (sort of a savepoint) so that, after feeding and compressing with setInput() + deflate() I can rollback/reset to that state to try with different data.

Looking at the API, this seems to me rather impossible... nor even reimplementing the Deflater (not at least if one wants to take advantage of the internal native implementation). Am I right? Any ideas or experiences?

Answer 1

It does not appear that the Java interface to zlib provides zlib's deflateCopy() operation. It is possible that the inherited clone operation is properly implemented and does a deflateCopy(), but I don't know.