The BinaryMapFn functor provides a balanced-binary-tree implementation of the ORD_MAP signature parameterized over the key type.

The original implementation was written by Stephen Adams and was based on the paper Binary Search Trees of Bounded Balance by Nievergelt and Reingold (SIAM Journal of Computing; March 1973).

It is recommended, however, that one use the RedBlackMapFn functor instead of BinaryMapFn, since experimentation has shown it to be faster across the board.