Or alternatively one could make good use of the existing buffer and use that to encode the sparse representation, like Antirez did in Redis: https://github.com

Or alternatively one could make good use of the existing buffer and use that to encode the sparse representation, like Antirez did in Redis: https://github.com/redis/redis/blob/unstable/src/hyperloglog.c#L100-L180 https://github.com/redis/redis/blob/unstable/src/hyperloglog...