From the Omni Group website:

OmniFoundation is The Omni Group’s extension to Apple’s Foundation framework. Besides several extremely useful extensions to Apple Foundation classes, OmniFoundation provides a horde of unique and powerful classes. Among the more interesting are:

• OFStringScanner - A blindingly fast unicode-safe alternative to NSStringScanner, for when you really need to burn through those character streams.
• OFRegularExpression - Powerful regular expression processing wrapped in an Objective-C shell. Combine with OFStringScanner for extra fun.
• OFTrie - Implementation of the popular trie data structure. Interfaces to OFStringScanner for rapid scanning of “longest” token elements.
• OFMessageQueue & OFQueueProcessor - Writing stable multithreaded applications is an error prone process. These classes help de-fang the savage beast.

OmniFoundation is a veritable treasure chest of programming goodies. Take a look for yourself at http://www.omnigroup.com/developer/sourcecode/