Consistent hashing is a scheme that provides hash table functionality in a way that the addition or removal of one slot does not significantly change the mapping of keys to slots.
In contrast, in most traditional hash tables, a change in the number of array slots causes nearly all keys to be remapped.
By using consistent hashing, only K/n keys need to be remapped on average, where K is the number of keys, and n is the number of slots.
Consistent is very useful in distributed caching systems.
It uses SimpleTest for unit testing.
· PHP 5 or higher