google/leveldb
LevelDB is a fast key-value storage library written at Google that provides an ordered mapping from string keys to string values. Authors: Sanjay Ghemawat ( sanjay@google.com) and Jeff Dean ( jeff@google.com) Keys and values are arbitrary byte arrays. Data is stored sorted by key. Callers can provide a custom comparison function to override the sort order.
https://github.com/google/leveldb