public class BitMap
extends java.lang.Object
Bitmap which supports indexing with long arguments. java.util.BitSet
provides all the functionality and performance we need, but requires integer
indexing.
Long indexing is implemented by keeping a Map of java.util.BitSets, where
each bitset covers 2^16 bits worth of values. The Bitmap may be sparse, in
that each segment is only instantiated when needed.
Note that this class is currently not thread safe; adding a new bitset
segment is not protected.