Judy is a C library that implements a dynamic array. Empty Judy arrays are
 declared with null pointers. A Judy array consumes memory only when
 populated yet can grow to take advantage of all available memory. Judy's key
 benefits are: scalability, performance, memory efficiency, and ease of use.
 Judy arrays are designed to grow without tuning into the peta-element range,
 scaling near O(log-base-256).
 .
 Judy arrays are accessed with insert, retrieve, and delete calls for number
 or string indexes. Configuration and tuning are not required -- in fact not
 possible. Judy offers sorting, counting, and neighbor/empty searching.
 Indexes can be sequential, clustered, periodic, or random -- it doesn't
 matter to the algorithm. Judy arrays can be arranged hierarchically to
 handle any bit patterns -- large indexes, sets of keys, etc.
 .
 Judy is often an improvement over common data structures such as: arrays,
 sparse arrays, hash tables, B-trees, binary trees, linear lists, skiplists,
 other sort and search algorithms, and counting functions.