AVLMAP is a key:data pair data mapping (associative array) library for C programming based on AVL balanced binary trees. Added features include ordered data retrieval forward or reverse, support for optional duplicate keys (e.g. an extra linked list not needed), and the ability to find the nearest member if an exact match isn't available. Both key and data types may be selected from a choice of C data types including string and array variations. One mapping always has one key type, but data types may be mixed within a mapping.
Calc is arbitrary precision arithmetic system that uses a C-like language. It's useful as a calculator, an algorithm prototype, and as a mathematical research tool. More importantly, calc provides a machine-independent means of computation. Calc comes with a rich set of builtin mathematical and programmatic functions.
cgi-util is a fast, easy to use C library for creating CGI programs. Functions are available for initialization (parsing), grabbing fields (by string, integer, double or boolean value), embedding HTML files, and more. It accepts both POST and GET request methods and has extensive error handling.
FriBidi is a free implementation of the Unicode Bidirectional (BiDi) Algorithm. It also provides utility functions to aid in the development of interactive editors and widgets that implement BiDi functionality. The BiDi algorithm is a prerequesite for supporting right-to-left scripts such as Hebrew, Arabic, Syriac, and Thaana.
GPP is a general-purpose preprocessor with customizable syntax, suitable for a wide range of preprocessing tasks. Its independence from any programming language makes it much more versatile than cpp, while its syntax is lighter and more flexible than that of m4. The syntax is fully customizable, which makes it possible to process text files, HTML, or source code equally efficiently in a variety of languages.