critbit

This package implements crit-bit trees, a key-value container type for storing keys that can be treated as bitstrings (e.g. ByteString and Text). Compared to the data structures from the containers and unordered-containers packages, you will find that sometimes the functions implemented in this package are faster, sometimes slower. In many cases, a CritBit tree provides performance close to that of a HashMap, while providing ordered storage and traversal like a Map.