What is the exact equation being used for sound volume?

I'm porting a project from another engine, and I'm trying to make the audio mix match. The other engine applies the volume adjustment using this equation:

     private int volumeAdjust(int sample, float volume) {
         float db1 = (float) (1 / MathUtils.rangeFraction(Math.pow(10, volume), 1, 10));
         int dbInv = (int) Math.round(VOLUME_RESOLUTION * db1);
         return (sample) / dbInv;
     }

This is a bit simplified from the actual code, but it illustrates that at this point, we are applying the volume directly to the samples, and we have the equation we want to use for this. To emulate exactly the same volume response in Unity, I would need to know what equation Unity uses for this.