This project is originally by Fabio Casadei, Antonio Savoldi, and Paolo Gubian; see https://sites.google.com/site/savolabs/Home/tools for the original location, and see http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.160.4644 for the paper describing the tool in detail. Note: I could not find an explicit license anywhere in the sources or on the web site, but "open source" is stated several times in the links above.