This repository contains the reference implementation of SnapTree,
a concurrent AVL tree with fast cloning, snapshots, and consistent
iteration.  It is described in the paper "A Practical Concurrent Binary
Search Tree", by N. Bronson, J. Casper, H. Chafi, and K. Olukotun,
published in PPoPP'10.

There are a variety of maps here.  SnapTreeMap is by far the
most well tested and robust.  It passes all of the unit tests for
ConcurrentSkipListMap, while also guaranteeing that clone() is an atomic
(O(1)) operation and that iteration is consistent.

http://ppl.stanford.edu/papers/ppopp207-bronson.pdf