Mirroring across plane


How do you guys code mirror position and rotation across plane. I mean like Mirror Joints does.
As far as I could do this is (kipping in mind plane YZ ) TX = TX *-1. RZ = RZ *-1, RY = RY *-1, RX = ((180-RX)*-1) and it works. I would like to know if there is more elegant way to do this.