radix_tree improvements

[igchor]

radix_tree improvements

• heterogeneous methods (opt-in, like for std::map)

• optimized lower/upper_bound

• reverse_iterator has problems with current operator->() implementation in radix_tree::iterator

• It would be nice to have some test for insert_or_assign / try_emplace where we use something like MoveableWrapper (something which is constructed from Moveable rvalue reference) as key and pass std::move(Moveable) to those methods. The we could check if the Moveable was actually moved from

• Libcxx tests for erase(iterator)

• Enable tests for radix (At least the code under ifdefs 'xxx' in tests/map/map_ctor_and_assignment.cpp and tests/map/map_txabort.cpp can be enabled)

• change value_type from std::pair to detail::pair

• optimize insert (implementation can take advantage of knowing the key)

• allow inline_string modifications (range/at methods in inline string)

• rollback iterator in case of transaction abort (in case of inline_string).

  After some thought, this improvement could be quite hard to implement. One solution would be to rollback the iterator's internal state through on_abort callback. However, when on_abort callback is called the iterator might not exists anymore and we have no way (?) of checking if it's still alive.