the CARL PLT group for the class of Spring 2017 is adopting this simple C library for hashmaps to use when implemeting our CARL language arrays.

This is the README from the original project:

This is a simple C hashmap, using strings for the keys.

Originally based on code by Eliot Back at http://elliottback.com/wp/hashmap-implementation-in-c/
Reworked by Pete Warden - http://petewarden.typepad.com/searchbrowser/2010/01/c-hashmap.html

main.c contains an example that tests the functionality of the hashmap module.
To compile it, run something like this on your system:
gcc main.c hashmap.c -o hashmaptest

There are no restrictions on how you reuse this code.