Where's the source code for rastertopclx?

[anonymous]

Does rastertopclx generate PCL-XL output stream?

CUPS DDK generated PPDs use rastertopclx filter. (There's no place to 
specify whether it's PCL5 or PCL 6 printer) and it works for my PCL5 
printer. So I guess it's not generating PCL6 stream.

What's the difference between rastertopclx and rastertohp then?

I can't find the source code for rastertopclx in the filter directory of 
cups-1.1.21 source code.

Where is it located?