Hi Joe,
an open source C++ implementation is an obvious next and required step for many potential users.
We (Pantor) are considering providing such an implementation.
The time required to create, release, and support that work is currently spent on a number of commercial Pantor activities.
We had commercial reasons to get a Java implementation in the hands of our clients, so that's why we started there.
On the Java side, what we have made available is sufficient for integration needs but there is a lot more to do performance and completeness wise.
We do have an internal C++ implementation, but not with the programming interface that we would target in an open source version.
I wish I could make a more clear commitment including a time plan, but we are not there just yet.
Kind Regards,
Anders