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 * Copyright (c) 2007, 2013, Oracle and/or its affiliates. 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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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.

 *

 * @author Karl Helgason

 */

public final 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;

    // concave: output = (20*log10(127^2/value^2)) / 96

    public static final int TRANSFORM_CONCAVE = 1;

    // convex: same as concave except that start and end point are reversed.

    public static final int TRANSFORM_CONVEX = 2;

    // switch: if value > avg(max,min) then max else min

    public static final int TRANSFORM_SWITCH = 3;

    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;

    }

}