SF_FrequencyModulate.java

/* For Copyright and License see LICENSE.txt and COPYING.txt in the root directory */
package com.nerdscentral.audio.pitch;

import java.util.List;

import com.nerdscentral.audio.core.SFSignal;
import com.nerdscentral.sython.Caster;
import com.nerdscentral.sython.SFPL_Operator;
import com.nerdscentral.sython.SFPL_RuntimeException;

public class SF_FrequencyModulate implements SFPL_Operator
{

    private static final long serialVersionUID = 1L;

    @Override
    public Object Interpret(final Object input) throws SFPL_RuntimeException
    {
        List<Object> l = Caster.makeBunch(input);
        SFSignal shape = Caster.makeSFSignal(l.get(1));
        SFSignal sampleA = Caster.makeSFSignal(l.get(0));
        if (sampleA.getLength() != shape.getLength()) throw new SFPL_RuntimeException(Messages.getString("SF_Resample.1"));  //$NON-NLS-1$
        int len = sampleA.getLength();
        SFSignal ret = sampleA.replicateEmpty();
        double pos = 0;
        // Perform a dry run to get the required timing correction
        for (int i = 0; i < len; ++i)
        {
            // ret.setSample(i, sampleA.getSampleCubic(pos));
            double sn = shape.getSample(i);
            if (sn > 0)
            {
                sn += 1.0d;
            }
            else if (sn == 0)
            {
                sn = 1.0d;
            }
            else
            {
                sn = -sn + 1.0d;
                sn = 1.0d / sn;
            }
            pos += sn;
        }
        double correction = (len - 1) / pos;
        // Now do it for real
        pos = 0;
        for (int i = 0; i < len; ++i)
        {
            ret.setSample(i, sampleA.getSampleCubic(pos * correction));
            double sn = shape.getSample(i);
            if (sn > 0)
            {
                sn += 1.0d;
            }
            else if (sn == 0)
            {
                sn = 1.0d;
            }
            else
            {
                sn = -sn + 1.0d;
                sn = 1.0d / sn;
            }
            pos += sn;
        }
        return ret;
    }

    @Override
    public String Word()
    {
        return Messages.getString("SF_FMModulate.0"); //$NON-NLS-1$
    }

}