hashit is a generic hash library implemented in C which supports multiple collision handling methods.
Nowadays not much work is going into it, but it's maintained :), just in case some bug comes out of nowhere.
Credit is due to Bob Jenkins, author of the default hash function used in hashit and which is available here along with a lot of material related to hashing.
Hashit development is centralized in launchpad.
To get the last code from the git repository, just type:
git clone https://git.launchpad.net/hashit
or in case you have a launchpad account with your ssh key properly configured:
git clone git+ssh://YOURUSER@git.launchpad.net/hashit