/*
  * Copyright 2007 Sun Microsystems, Inc.  All Rights Reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Sun designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Sun in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  */ 

package com.sun.media.sound;

/**
 * A standard transformer used in connection blocks.
 * It expects input values to be between 0 and 1.
 * 
 * The result of the transform is 
 * between 0 and 1 if polarity = unipolar and 
 * between -1 and 1 if polarity = bipolar.
 * 
 * These constraints only applies to Concave, Convex and Switch transforms.
 * 
 * @version %I%, %E%
 * @author Karl Helgason
 */ 
public class ModelStandardTransform implements ModelTransform {

	public static final boolean DIRECTION_MIN2MAX = false;
	public static final boolean DIRECTION_MAX2MIN = true;	
	public static final boolean POLARITY_UNIPOLAR = false;
	public static final boolean POLARITY_BIPOLAR  = true;
	
	public static final int TRANSFORM_LINEAR    = 0;
	public static final int TRANSFORM_CONCAVE   = 1;  // output = (20*log10(127^2/value^2)) / 96 
	public static final int TRANSFORM_CONVEX    = 2;  // same as concave except that start and end point are reversed.
	public static final int TRANSFORM_SWITCH    = 3;  // if value > avg(max,min) then max else min
	public static final int TRANSFORM_ABSOLUTE  = 4;

	private boolean direction = DIRECTION_MIN2MAX;
	private boolean polarity = POLARITY_UNIPOLAR;
	private int transform = TRANSFORM_LINEAR;
	
	public ModelStandardTransform()
	{
	}
	
	public ModelStandardTransform(boolean direction)
	{
		this.direction = direction;
	}	
	
	public ModelStandardTransform(boolean direction, boolean polarity)
	{
		this.direction = direction;
		this.polarity = polarity;
	}	
	
	public ModelStandardTransform(boolean direction, boolean polarity, int transform)
	{
		this.direction = direction;
		this.polarity = polarity;
		this.transform = transform;		
	}
		
	public double transform(double value) {		
		double s;
		double a;
		if(direction == DIRECTION_MAX2MIN)
			value = 1.0 - value;
		if(polarity == POLARITY_BIPOLAR)
			value = value*2.0 - 1.0;		
		switch (transform) {
		case TRANSFORM_CONCAVE:		
			s = Math.signum(value);
			a = Math.abs(value);
			a = -((5.0/12.0)/Math.log(10))*Math.log(1.0 - a);
			if(a < 0) a = 0; else if(a > 1) a = 1;
			return s*a; 
		case TRANSFORM_CONVEX:
			s = Math.signum(value);
			a = Math.abs(value);
			a = 1.0+((5.0/12.0)/Math.log(10))*Math.log(a);					
			if(a < 0) a = 0; else if(a > 1) a = 1;
			return s*a; 
		case TRANSFORM_SWITCH:	
			if(polarity == POLARITY_BIPOLAR)
				return (value > 0)?1:-1;
			else
				return (value > 0.5)?1:0;
		case TRANSFORM_ABSOLUTE:
			return Math.abs(value);	
		default:
			break;
		}		
		
		return value;
	}
	
	public boolean getDirection() {
		return direction;
	}
	public void setDirection(boolean direction) {
		this.direction = direction;
	}
	public boolean getPolarity() {
		return polarity;
	}
	public void setPolarity(boolean polarity) {
		this.polarity = polarity;
	}
	public int getTransform() {
		return transform;
	}
	public void setTransform(int transform) {
		this.transform = transform;
	}		


}