You can download the "Source Code for all platforms" from this page
http://pianobooster.sourceforge.net/download.html
or to browse the source code on line from this page.
http://pianobooster.svn.sourceforge.net/viewvc/pianobooster/trunk/PianoBooster/src/Then count up the number of .cpp files in the "PianoBooster/src" directory.
Louis