//gkc: simple sample-wise Limiter

//translated from p100 of DAFX-Zolzer



public class Limiter extends delayp {



    //ugens

    UGen @ in;

    

    //constants for the algorithm

    1.0 => float slope;

    0.5 => float tresh;

    0.01 => float rt; //release const

    0.4 => float at; //attack const



    //maybe delay should be nonzero?



    //run the limiter

    public void limit() {

        float xd; //sidechain - tracks the signal volume

        while( true ) {

            float f; //the gain function



            //'a' is signal left after subtracting xd

            math.fabs( in.last() )-xd => float a;



            //a is a positive diff, don't let it be negative

            if ( a < 0 ) 0=>a;

            

            //the attack/release exponential filter

            xd*(1-rt)+at*a => xd;



            //this implements the function f

            if ( xd > tresh ) {

                //math.pow( 10, -slope*(math.log10(xd)-math.log10(tresh)) )

                //=> f;



                //this should be the same thing

                math.pow( xd/tresh, -slope ) => f;

                

            } else {

                1.0 => f;

            }



            //set the gain on this

            this.gain( f );



            //move time forward

            1::samp => now;

        }

    }

    

    public void input( UGen in ) {

        in @=> this.in; //capture the in ref

        in => this; //connect input

    }



}