SFXR was a tool made for the 10th Ludum Dare competition held in December 2007. It was written in C++ and ran on Windows/Mac/Linux.
Then it was ported to ActionScript, renamed to BFXR. New waveforms and filters were added.
I ported it back to C++.
A lot of time related code doesn't take samplerate into account, you should only use this at 44100 Hz.