MixerInputStream.java

/*
 * Mobicents, Communications Middleware
 * 
 * Copyright (c) 2008, Red Hat Middleware LLC or third-party
 * contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Middleware LLC.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program 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 Lesser General Public License
 * for more details.
 *
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 *
 * Boston, MA  02110-1301  USA
 */
package org.mobicents.media.server.impl.resource.cnf;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.mobicents.media.Buffer;
import org.mobicents.media.Format;
import org.mobicents.media.server.impl.AbstractSink;

/**
 *
 * @author Oleg Kulikov
 */
public class MixerInputStream extends AbstractSink {

    private List<Buffer> buffers = Collections.synchronizedList(new ArrayList());
    private int jitter;
    private long duration;
    protected AudioMixer mixer;

    /**
     * Creates new input stream.
     * 
     * @param mixer
     * @param jitter
     */
    public MixerInputStream(AudioMixer mixer, int jitter) {
        super("MixerInputStream");
        this.mixer = mixer;
        this.jitter = jitter;
    }

    @Override
    public String getId() {
        return mixer.getId();
    }

    /**
     * Informs when input stream has enouph data for mixing.
     * 
     * @return return true when stream has enouph data for mixing.
     */
    public boolean isReady() {
        return !buffers.isEmpty();
    }

    /**
     * Gets the current jitter.
     * 
     * @return jitter value in milliseconds.
     */
    public long getJitter() {
        return duration;
    }

    /**
     * (Non Java-doc.)
     * 
     * @see org.mobicents.media.server.impl.AbstractSink#onMediaTransfer(org.mobicents.media.Buffer) 
     */
    public void onMediaTransfer(Buffer buffer) throws IOException {
        if (mixer == null) {
            return;
        }

        if (duration + buffer.getDuration() > jitter) {
            return;
        }

        Buffer buff = new Buffer();
        buff.copy(buffer);
        
        duration += buff.getDuration();
        buffers.add(buff);
    }

    /**
     * Reads media buffer from this stream with specified duration.
     * 
     * @param duration the duration of the requested buffer in milliseconds.
     * @return buffer which contains duration ms media for 8000Hz, 16bit, linear audio.
     */
    public byte[] read(int duration) {
        int size = 16 * duration;
        byte[] media = new byte[size];

        int count = 0;
        while (count < size && !buffers.isEmpty()) {
            Buffer buff = buffers.get(0);

            if (buff.isEOM() || buff.getData() == null) {
                buffers.remove(buff);
                this.duration -= buff.getDuration();
                buff.dispose();
                break;
            }

            int len = Math.min(size - count, buff.getLength() - buff.getOffset());
            System.arraycopy(buff.getData(), buff.getOffset(), media, count, len);

            count += len;
            buff.setOffset(buff.getOffset() + len);

            if (buff.getOffset() == buff.getLength()) {
                buffers.remove(buff);
                this.duration -= buff.getDuration();
                buff.dispose();
            }
        }

        return media;
    }


    /**
     * (Non Java-doc.)
     * 
     * @see org.mobicents.media.MediaSink.isAcceptable(Format).
     */
    public boolean isAcceptable(Format fmt) {
        return fmt.matches(AudioMixer.LINEAR);
    }

    /**
     * (Non Java-doc.)
     * 
     * @see org.mobicents.media.MediaSink#getFormats() 
     */
    public Format[] getFormats() {
        return AudioMixer.formats;
    }
    
    @Override
    public String toString() {
        return mixer.toString();
    }
    
}