/*
 * Copyright (c) 2002, 2020, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.sun.media.sound;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Vector;

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.BooleanControl;
import javax.sound.sampled.Clip;
import javax.sound.sampled.Control;
import javax.sound.sampled.DataLine;
import javax.sound.sampled.FloatControl;
import javax.sound.sampled.Line;
import javax.sound.sampled.LineUnavailableException;
import javax.sound.sampled.SourceDataLine;
import javax.sound.sampled.TargetDataLine;

// IDEA:
// Use java.util.concurrent.Semaphore,
// java.util.concurrent.locks.ReentrantLock and other new classes/methods
// to improve this class's thread safety.

A Mixer which provides direct access to audio devices.
Author:
Florian Bomers/**
 * A Mixer which provides direct access to audio devices.
 *
 * @author Florian Bomers
 */
final class DirectAudioDevice extends AbstractMixer {

    private static final int CLIP_BUFFER_TIME = 1000; // in milliseconds

    private static final int DEFAULT_LINE_BUFFER_TIME = 500; // in milliseconds

    DirectAudioDevice(DirectAudioDeviceProvider.DirectAudioDeviceInfo portMixerInfo) {
        // pass in Line.Info, mixer, controls
        super(portMixerInfo,              // Mixer.Info
              null,                       // Control[]
              null,                       // Line.Info[] sourceLineInfo
              null);                      // Line.Info[] targetLineInfo
        // source lines
        DirectDLI srcLineInfo = createDataLineInfo(true);
        if (srcLineInfo != null) {
            sourceLineInfo = new Line.Info[2];
            // SourcedataLine
            sourceLineInfo[0] = srcLineInfo;
            // Clip
            sourceLineInfo[1] = new DirectDLI(Clip.class, srcLineInfo.getFormats(),
                                              srcLineInfo.getHardwareFormats(),
                                              32, // arbitrary minimum buffer size
                                              AudioSystem.NOT_SPECIFIED);
        } else {
            sourceLineInfo = new Line.Info[0];
        }

        // TargetDataLine
        DataLine.Info dstLineInfo = createDataLineInfo(false);
        if (dstLineInfo != null) {
            targetLineInfo = new Line.Info[1];
            targetLineInfo[0] = dstLineInfo;
        } else {
            targetLineInfo = new Line.Info[0];
        }
    }

    private DirectDLI createDataLineInfo(boolean isSource) {
        Vector<AudioFormat> formats = new Vector<>();
        AudioFormat[] hardwareFormatArray = null;
        AudioFormat[] formatArray = null;

        synchronized(formats) {
            nGetFormats(getMixerIndex(), getDeviceID(),
                        isSource /* true:SourceDataLine/Clip, false:TargetDataLine */,
                        formats);
            if (formats.size() > 0) {
                int size = formats.size();
                int formatArraySize = size;
                hardwareFormatArray = new AudioFormat[size];
                for (int i = 0; i < size; i++) {
                    AudioFormat format = formats.elementAt(i);
                    hardwareFormatArray[i] = format;
                    int bits = format.getSampleSizeInBits();
                    boolean isSigned = format.getEncoding().equals(AudioFormat.Encoding.PCM_SIGNED);
                    boolean isUnsigned = format.getEncoding().equals(AudioFormat.Encoding.PCM_UNSIGNED);
                    if ((isSigned || isUnsigned)) {
                        // will insert a magically converted format here
                        formatArraySize++;
                    }
                }
                formatArray = new AudioFormat[formatArraySize];
                int formatArrayIndex = 0;
                for (int i = 0; i < size; i++) {
                    AudioFormat format = hardwareFormatArray[i];
                    formatArray[formatArrayIndex++] = format;
                    int bits = format.getSampleSizeInBits();
                    boolean isSigned = format.getEncoding().equals(AudioFormat.Encoding.PCM_SIGNED);
                    boolean isUnsigned = format.getEncoding().equals(AudioFormat.Encoding.PCM_UNSIGNED);
                    // add convenience formats (automatic conversion)
                    if (bits == 8) {
                        // add the other signed'ness for 8-bit
                        if (isSigned) {
                            formatArray[formatArrayIndex++] =
                                new AudioFormat(AudioFormat.Encoding.PCM_UNSIGNED,
                                    format.getSampleRate(), bits, format.getChannels(),
                                    format.getFrameSize(), format.getSampleRate(),
                                    format.isBigEndian());
                        }
                        else if (isUnsigned) {
                            formatArray[formatArrayIndex++] =
                                new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
                                    format.getSampleRate(), bits, format.getChannels(),
                                    format.getFrameSize(), format.getSampleRate(),
                                    format.isBigEndian());
                        }
                    } else if (bits > 8 && (isSigned || isUnsigned)) {
                        // add the other endian'ness for more than 8-bit
                        formatArray[formatArrayIndex++] =
                            new AudioFormat(format.getEncoding(),
                                              format.getSampleRate(), bits,
                                              format.getChannels(),
                                              format.getFrameSize(),
                                              format.getSampleRate(),
                                              !format.isBigEndian());
                    }
                    //System.out.println("Adding "+v.get(v.size()-1));
                }
            }
        }
        // todo: find out more about the buffer size ?
        if (formatArray != null) {
            return new DirectDLI(isSource?SourceDataLine.class:TargetDataLine.class,
                                 formatArray, hardwareFormatArray,
                                 32, // arbitrary minimum buffer size
                                 AudioSystem.NOT_SPECIFIED);
        }
        return null;
    }

    // ABSTRACT MIXER: ABSTRACT METHOD IMPLEMENTATIONS

    @Override
    public Line getLine(Line.Info info) throws LineUnavailableException {
        Line.Info fullInfo = getLineInfo(info);
        if (fullInfo == null) {
            throw new IllegalArgumentException("Line unsupported: " + info);
        }
        if (fullInfo instanceof DataLine.Info) {

            DataLine.Info dataLineInfo = (DataLine.Info)fullInfo;
            AudioFormat lineFormat;
            int lineBufferSize = AudioSystem.NOT_SPECIFIED;

            // if a format is specified by the info class passed in, use it.
            // otherwise use a format from fullInfo.

            AudioFormat[] supportedFormats = null;

            if (info instanceof DataLine.Info) {
                supportedFormats = ((DataLine.Info)info).getFormats();
                lineBufferSize = ((DataLine.Info)info).getMaxBufferSize();
            }

            if ((supportedFormats == null) || (supportedFormats.length == 0)) {
                // use the default format
                lineFormat = null;
            } else {
                // use the last format specified in the line.info object passed
                // in by the app
                lineFormat = supportedFormats[supportedFormats.length-1];

                // if something is not specified, use default format
                if (!Toolkit.isFullySpecifiedPCMFormat(lineFormat)) {
                    lineFormat = null;
                }
            }

            if (dataLineInfo.getLineClass().isAssignableFrom(DirectSDL.class)) {
                return new DirectSDL(dataLineInfo, lineFormat, lineBufferSize, this);
            }
            if (dataLineInfo.getLineClass().isAssignableFrom(DirectClip.class)) {
                return new DirectClip(dataLineInfo, lineFormat, lineBufferSize, this);
            }
            if (dataLineInfo.getLineClass().isAssignableFrom(DirectTDL.class)) {
                return new DirectTDL(dataLineInfo, lineFormat, lineBufferSize, this);
            }
        }
        throw new IllegalArgumentException("Line unsupported: " + info);
    }

    @Override
    public int getMaxLines(Line.Info info) {
        Line.Info fullInfo = getLineInfo(info);

        // if it's not supported at all, return 0.
        if (fullInfo == null) {
            return 0;
        }

        if (fullInfo instanceof DataLine.Info) {
            // DirectAudioDevices should mix !
            return getMaxSimulLines();
        }

        return 0;
    }

    @Override
    protected void implOpen() throws LineUnavailableException {
    }

    @Override
    protected void implClose() {
    }

    @Override
    protected void implStart() {
    }

    @Override
    protected void implStop() {
    }

    int getMixerIndex() {
        return ((DirectAudioDeviceProvider.DirectAudioDeviceInfo) getMixerInfo()).getIndex();
    }

    int getDeviceID() {
        return ((DirectAudioDeviceProvider.DirectAudioDeviceInfo) getMixerInfo()).getDeviceID();
    }

    int getMaxSimulLines() {
        return ((DirectAudioDeviceProvider.DirectAudioDeviceInfo) getMixerInfo()).getMaxSimulLines();
    }

    private static void addFormat(Vector<AudioFormat> v, int bits, int frameSizeInBytes, int channels, float sampleRate,
                                  int encoding, boolean signed, boolean bigEndian) {
        AudioFormat.Encoding enc = null;
        switch (encoding) {
        case PCM:
            enc = signed?AudioFormat.Encoding.PCM_SIGNED:AudioFormat.Encoding.PCM_UNSIGNED;
            break;
        case ULAW:
            enc = AudioFormat.Encoding.ULAW;
            if (bits != 8) {
                if (Printer.err) Printer.err("DirectAudioDevice.addFormat called with ULAW, but bitsPerSample="+bits);
                bits = 8; frameSizeInBytes = channels;
            }
            break;
        case ALAW:
            enc = AudioFormat.Encoding.ALAW;
            if (bits != 8) {
                if (Printer.err) Printer.err("DirectAudioDevice.addFormat called with ALAW, but bitsPerSample="+bits);
                bits = 8; frameSizeInBytes = channels;
            }
            break;
        }
        if (enc==null) {
            if (Printer.err) Printer.err("DirectAudioDevice.addFormat called with unknown encoding: "+encoding);
            return;
        }
        if (frameSizeInBytes <= 0) {
            if (channels > 0) {
                frameSizeInBytes = ((bits + 7) / 8) * channels;
            } else {
                frameSizeInBytes = AudioSystem.NOT_SPECIFIED;
            }
        }
        v.add(new AudioFormat(enc, sampleRate, bits, channels, frameSizeInBytes, sampleRate, bigEndian));
    }

    protected static AudioFormat getSignOrEndianChangedFormat(AudioFormat format) {
        boolean isSigned = format.getEncoding().equals(AudioFormat.Encoding.PCM_SIGNED);
        boolean isUnsigned = format.getEncoding().equals(AudioFormat.Encoding.PCM_UNSIGNED);
        if (format.getSampleSizeInBits() > 8 && isSigned) {
            // if this is PCM_SIGNED and 16-bit or higher, then try with endian-ness magic
            return new AudioFormat(format.getEncoding(),
                                   format.getSampleRate(), format.getSampleSizeInBits(), format.getChannels(),
                                   format.getFrameSize(), format.getFrameRate(), !format.isBigEndian());
        }
        else if (format.getSampleSizeInBits() == 8 && (isSigned || isUnsigned)) {
            // if this is PCM and 8-bit, then try with signed-ness magic
            return new AudioFormat(isSigned?AudioFormat.Encoding.PCM_UNSIGNED:AudioFormat.Encoding.PCM_SIGNED,
                                   format.getSampleRate(), format.getSampleSizeInBits(), format.getChannels(),
                                   format.getFrameSize(), format.getFrameRate(), format.isBigEndian());
        }
        return null;
    }

    
Private inner class for the DataLine.Info objects
adds a little magic for the isFormatSupported so
that the automagic conversion of endianness and sign
does not show up in the formats array.
I.e. the formats array contains only the formats
that are really supported by the hardware,
but isFormatSupported() also returns true
for formats with wrong endianness.
/**
     * Private inner class for the DataLine.Info objects
     * adds a little magic for the isFormatSupported so
     * that the automagic conversion of endianness and sign
     * does not show up in the formats array.
     * I.e. the formats array contains only the formats
     * that are really supported by the hardware,
     * but isFormatSupported() also returns true
     * for formats with wrong endianness.
     */
    private static final class DirectDLI extends DataLine.Info {
        final AudioFormat[] hardwareFormats;

        private DirectDLI(Class<?> clazz, AudioFormat[] formatArray,
                          AudioFormat[] hardwareFormatArray,
                          int minBuffer, int maxBuffer) {
            super(clazz, formatArray, minBuffer, maxBuffer);
            this.hardwareFormats = hardwareFormatArray;
        }

        public boolean isFormatSupportedInHardware(AudioFormat format) {
            if (format == null) return false;
            for (int i = 0; i < hardwareFormats.length; i++) {
                if (format.matches(hardwareFormats[i])) {
                    return true;
                }
            }
            return false;
        }

        /*public boolean isFormatSupported(AudioFormat format) {
         *   return isFormatSupportedInHardware(format)
         *      || isFormatSupportedInHardware(getSignOrEndianChangedFormat(format));
         *}
         */

         private AudioFormat[] getHardwareFormats() {
             return hardwareFormats;
         }
    }

    
Private inner class as base class for direct lines.
/**
     * Private inner class as base class for direct lines.
     */
    private static class DirectDL extends AbstractDataLine implements EventDispatcher.LineMonitor {
        protected final int mixerIndex;
        protected final int deviceID;
        protected long id;
        protected int waitTime;
        protected volatile boolean flushing = false;
        protected final boolean isSource;         // true for SourceDataLine, false for TargetDataLine
        protected volatile long bytePosition;
        protected volatile boolean doIO = false;     // true in between start() and stop() calls
        protected volatile boolean stoppedWritten = false; // true if a write occurred in stopped state
        protected volatile boolean drained = false; // set to true when drain function returns, set to false in write()
        protected boolean monitoring = false;

        // if native needs to manually swap samples/convert sign, this
        // is set to the framesize
        protected int softwareConversionSize = 0;
        protected AudioFormat hardwareFormat;

        private final Gain gainControl = new Gain();
        private final Mute muteControl = new Mute();
        private final Balance balanceControl = new Balance();
        private final Pan panControl = new Pan();
        private float leftGain, rightGain;
        protected volatile boolean noService = false; // do not run the nService method

        // Guards all native calls.
        protected final Object lockNative = new Object();

        protected DirectDL(DataLine.Info info,
                           DirectAudioDevice mixer,
                           AudioFormat format,
                           int bufferSize,
                           int mixerIndex,
                           int deviceID,
                           boolean isSource) {
            super(info, mixer, null, format, bufferSize);
            this.mixerIndex = mixerIndex;
            this.deviceID = deviceID;
            this.waitTime = 10; // 10 milliseconds default wait time
            this.isSource = isSource;

        }

        @Override
        void implOpen(AudioFormat format, int bufferSize) throws LineUnavailableException {
            // $$fb part of fix for 4679187: Clip.open() throws unexpected Exceptions
            Toolkit.isFullySpecifiedAudioFormat(format);

            // check for record permission
            if (!isSource) {
                JSSecurityManager.checkRecordPermission();
            }
            int encoding = PCM;
            if (format.getEncoding().equals(AudioFormat.Encoding.ULAW)) {
                encoding = ULAW;
            }
            else if (format.getEncoding().equals(AudioFormat.Encoding.ALAW)) {
                encoding = ALAW;
            }

            if (bufferSize <= AudioSystem.NOT_SPECIFIED) {
                bufferSize = (int) Toolkit.millis2bytes(format, DEFAULT_LINE_BUFFER_TIME);
            }

            DirectDLI ddli = null;
            if (info instanceof DirectDLI) {
                ddli = (DirectDLI) info;
            }

            /* set up controls */
            if (isSource) {
                if (!format.getEncoding().equals(AudioFormat.Encoding.PCM_SIGNED)
                    && !format.getEncoding().equals(AudioFormat.Encoding.PCM_UNSIGNED)) {
                    // no controls for non-PCM formats */
                    controls = new Control[0];
                }
                else if (format.getChannels() > 2
                         || format.getSampleSizeInBits() > 16) {
                    // no support for more than 2 channels or more than 16 bits
                    controls = new Control[0];
                } else {
                    if (format.getChannels() == 1) {
                        controls = new Control[2];
                    } else {
                        controls = new Control[4];
                        controls[2] = balanceControl;
                        /* to keep compatibility with apps that rely on
                         * MixerSourceLine's PanControl
                         */
                        controls[3] = panControl;
                    }
                    controls[0] = gainControl;
                    controls[1] = muteControl;
                }
            }
            hardwareFormat = format;

            /* some magic to account for not-supported endianness or signed-ness */
            softwareConversionSize = 0;
            if (ddli != null && !ddli.isFormatSupportedInHardware(format)) {
                AudioFormat newFormat = getSignOrEndianChangedFormat(format);
                if (ddli.isFormatSupportedInHardware(newFormat)) {
                    // apparently, the new format can be used.
                    hardwareFormat = newFormat;
                    // So do endian/sign conversion in software
                    softwareConversionSize = format.getFrameSize() / format.getChannels();
                }
            }

            // align buffer to full frames
            bufferSize = ( bufferSize / format.getFrameSize()) * format.getFrameSize();

            id = nOpen(mixerIndex, deviceID, isSource,
                    encoding,
                    hardwareFormat.getSampleRate(),
                    hardwareFormat.getSampleSizeInBits(),
                    hardwareFormat.getFrameSize(),
                    hardwareFormat.getChannels(),
                    hardwareFormat.getEncoding().equals(
                        AudioFormat.Encoding.PCM_SIGNED),
                    hardwareFormat.isBigEndian(),
                    bufferSize);

            if (id == 0) {
                // TODO: nicer error messages...
                throw new LineUnavailableException(
                        "line with format "+format+" not supported.");
            }

            this.bufferSize = nGetBufferSize(id, isSource);
            if (this.bufferSize < 1) {
                // this is an error!
                this.bufferSize = bufferSize;
            }
            this.format = format;
            // wait time = 1/4 of buffer time
            waitTime = (int) Toolkit.bytes2millis(format, this.bufferSize) / 4;
            if (waitTime < 10) {
                waitTime = 1;
            }
            else if (waitTime > 1000) {
                // we have seen large buffer sizes!
                // never wait for more than a second
                waitTime = 1000;
            }
            bytePosition = 0;
            stoppedWritten = false;
            doIO = false;
            calcVolume();
        }

        @Override
        void implStart() {
            // check for record permission
            if (!isSource) {
                JSSecurityManager.checkRecordPermission();
            }

            synchronized (lockNative)
            {
                nStart(id, isSource);
            }
            // check for monitoring/servicing
            monitoring = requiresServicing();
            if (monitoring) {
                getEventDispatcher().addLineMonitor(this);
            }

            synchronized(lock) {
                doIO = true;
                // need to set Active and Started
                // note: the current API always requires that
                //       Started and Active are set at the same time...
                if (isSource && stoppedWritten) {
                    setStarted(true);
                    setActive(true);
                }
            }
        }

        @Override
        void implStop() {
            // check for record permission
            if (!isSource) {
                JSSecurityManager.checkRecordPermission();
            }

            if (monitoring) {
                getEventDispatcher().removeLineMonitor(this);
                monitoring = false;
            }
            synchronized (lockNative) {
                nStop(id, isSource);
            }
            // wake up any waiting threads
            synchronized(lock) {
                // need to set doIO to false before notifying the
                // read/write thread, that's why isStartedRunning()
                // cannot be used
                doIO = false;
                setActive(false);
                setStarted(false);
                lock.notifyAll();
            }
            stoppedWritten = false;
        }

        @Override
        void implClose() {
            // check for record permission
            if (!isSource) {
                JSSecurityManager.checkRecordPermission();
            }

            // be sure to remove this monitor
            if (monitoring) {
                getEventDispatcher().removeLineMonitor(this);
                monitoring = false;
            }

            doIO = false;
            long oldID = id;
            id = 0;
            synchronized (lockNative) {
                nClose(oldID, isSource);
            }
            bytePosition = 0;
            softwareConversionSize = 0;
        }

        @Override
        public int available() {
            if (id == 0) {
                return 0;
            }
            int a;
            synchronized (lockNative) {
                a = nAvailable(id, isSource);
            }
            return a;
        }

        @Override
        public void drain() {
            noService = true;
            // additional safeguard against draining forever
            // this occurred on Solaris 8 x86, probably due to a bug
            // in the audio driver
            int counter = 0;
            long startPos = getLongFramePosition();
            boolean posChanged = false;
            while (!drained) {
                synchronized (lockNative) {
                    if ((id == 0) || (!doIO) || !nIsStillDraining(id, isSource))
                        break;
                }
                // check every now and then for a new position
                if ((counter % 5) == 4) {
                    long thisFramePos = getLongFramePosition();
                    posChanged = posChanged | (thisFramePos != startPos);
                    if ((counter % 50) > 45) {
                        // when some time elapsed, check that the frame position
                        // really changed
                        if (!posChanged) {
                            if (Printer.err) Printer.err("Native reports isDraining, but frame position does not increase!");
                            break;
                        }
                        posChanged = false;
                        startPos = thisFramePos;
                    }
                }
                counter++;
                synchronized(lock) {
                    try {
                        lock.wait(10);
                    } catch (InterruptedException ie) {}
                }
            }

            if (doIO && id != 0) {
                drained = true;
            }
            noService = false;
        }

        @Override
        public void flush() {
            if (id != 0) {
                // first stop ongoing read/write method
                flushing = true;
                synchronized(lock) {
                    lock.notifyAll();
                }
                synchronized (lockNative) {
                    if (id != 0) {
                        // then flush native buffers
                        nFlush(id, isSource);
                    }
                }
                drained = true;
            }
        }

        // replacement for getFramePosition (see AbstractDataLine)
        @Override
        public long getLongFramePosition() {
            long pos;
            synchronized (lockNative) {
                pos = nGetBytePosition(id, isSource, bytePosition);
            }
            // hack because ALSA sometimes reports wrong framepos
            if (pos < 0) {
                pos = 0;
            }
            return (pos / getFormat().getFrameSize());
        }

        /*
         * write() belongs into SourceDataLine and Clip,
         * so define it here and make it accessible by
         * declaring the respective interfaces with DirectSDL and DirectClip
         */
        public int write(byte[] b, int off, int len) {
            flushing = false;
            if (len == 0) {
                return 0;
            }
            if (len < 0) {
                throw new IllegalArgumentException("illegal len: "+len);
            }
            if (len % getFormat().getFrameSize() != 0) {
                throw new IllegalArgumentException("illegal request to write "
                                                   +"non-integral number of frames ("
                                                   +len+" bytes, "
                                                   +"frameSize = "+getFormat().getFrameSize()+" bytes)");
            }
            if (off < 0) {
                throw new ArrayIndexOutOfBoundsException(off);
            }
            if ((long)off + (long)len > (long)b.length) {
                throw new ArrayIndexOutOfBoundsException(b.length);
            }
            synchronized(lock) {
                if (!isActive() && doIO) {
                    // this is not exactly correct... would be nicer
                    // if the native sub system sent a callback when IO really
                    // starts
                    setActive(true);
                    setStarted(true);
                }
            }
            int written = 0;
            while (!flushing) {
                int thisWritten;
                synchronized (lockNative) {
                    thisWritten = nWrite(id, b, off, len,
                            softwareConversionSize,
                            leftGain, rightGain);
                    if (thisWritten < 0) {
                        // error in native layer
                        break;
                    }
                    bytePosition += thisWritten;
                    if (thisWritten > 0) {
                        drained = false;
                    }
                }
                len -= thisWritten;
                written += thisWritten;
                if (doIO && len > 0) {
                    off += thisWritten;
                    synchronized (lock) {
                        try {
                            lock.wait(waitTime);
                        } catch (InterruptedException ie) {}
                    }
                } else {
                    break;
                }
            }
            if (written > 0 && !doIO) {
                stoppedWritten = true;
            }
            return written;
        }

        protected boolean requiresServicing() {
            return nRequiresServicing(id, isSource);
        }

        // called from event dispatcher for lines that need servicing
        @Override
        public void checkLine() {
            synchronized (lockNative) {
                if (monitoring
                        && doIO
                        && id != 0
                        && !flushing
                        && !noService) {
                    nService(id, isSource);
                }
            }
        }

        private void calcVolume() {
            if (getFormat() == null) {
                return;
            }
            if (muteControl.getValue()) {
                leftGain = 0.0f;
                rightGain = 0.0f;
                return;
            }
            float gain = gainControl.getLinearGain();
            if (getFormat().getChannels() == 1) {
                // trivial case: only use gain
                leftGain = gain;
                rightGain = gain;
            } else {
                // need to combine gain and balance
                float bal = balanceControl.getValue();
                if (bal < 0.0f) {
                    // left
                    leftGain = gain;
                    rightGain = gain * (bal + 1.0f);
                } else {
                    leftGain = gain * (1.0f - bal);
                    rightGain = gain;
                }
            }
        }

        /////////////////// CONTROLS /////////////////////////////

        protected final class Gain extends FloatControl {

            private float linearGain = 1.0f;

            private Gain() {

                super(FloatControl.Type.MASTER_GAIN,
                      Toolkit.linearToDB(0.0f),
                      Toolkit.linearToDB(2.0f),
                      Math.abs(Toolkit.linearToDB(1.0f)-Toolkit.linearToDB(0.0f))/128.0f,
                      -1,
                      0.0f,
                      "dB", "Minimum", "", "Maximum");
            }

            @Override
            public void setValue(float newValue) {
                // adjust value within range ?? spec says IllegalArgumentException
                //newValue = Math.min(newValue, getMaximum());
                //newValue = Math.max(newValue, getMinimum());

                float newLinearGain = Toolkit.dBToLinear(newValue);
                super.setValue(Toolkit.linearToDB(newLinearGain));
                // if no exception, commit to our new gain
                linearGain = newLinearGain;
                calcVolume();
            }

            float getLinearGain() {
                return linearGain;
            }
        } // class Gain

        private final class Mute extends BooleanControl {

            private Mute() {
                super(BooleanControl.Type.MUTE, false, "True", "False");
            }

            @Override
            public void setValue(boolean newValue) {
                super.setValue(newValue);
                calcVolume();
            }
        }  // class Mute

        private final class Balance extends FloatControl {

            private Balance() {
                super(FloatControl.Type.BALANCE, -1.0f, 1.0f, (1.0f / 128.0f), -1, 0.0f,
                      "", "Left", "Center", "Right");
            }

            @Override
            public void setValue(float newValue) {
                setValueImpl(newValue);
                panControl.setValueImpl(newValue);
                calcVolume();
            }

            void setValueImpl(float newValue) {
                super.setValue(newValue);
            }

        } // class Balance

        private final class Pan extends FloatControl {

            private Pan() {
                super(FloatControl.Type.PAN, -1.0f, 1.0f, (1.0f / 128.0f), -1, 0.0f,
                      "", "Left", "Center", "Right");
            }

            @Override
            public void setValue(float newValue) {
                setValueImpl(newValue);
                balanceControl.setValueImpl(newValue);
                calcVolume();
            }
            void setValueImpl(float newValue) {
                super.setValue(newValue);
            }
        } // class Pan
    } // class DirectDL

    
Private inner class representing a SourceDataLine.
/**
     * Private inner class representing a SourceDataLine.
     */
    private static final class DirectSDL extends DirectDL
            implements SourceDataLine {

        private DirectSDL(DataLine.Info info,
                          AudioFormat format,
                          int bufferSize,
                          DirectAudioDevice mixer) {
            super(info, mixer, format, bufferSize, mixer.getMixerIndex(), mixer.getDeviceID(), true);
        }
    }

    
Private inner class representing a TargetDataLine.
/**
     * Private inner class representing a TargetDataLine.
     */
    private static final class DirectTDL extends DirectDL
            implements TargetDataLine {

        private DirectTDL(DataLine.Info info,
                          AudioFormat format,
                          int bufferSize,
                          DirectAudioDevice mixer) {
            super(info, mixer, format, bufferSize, mixer.getMixerIndex(), mixer.getDeviceID(), false);
        }

        @Override
        public int read(byte[] b, int off, int len) {
            flushing = false;
            if (len == 0) {
                return 0;
            }
            if (len < 0) {
                throw new IllegalArgumentException("illegal len: "+len);
            }
            if (len % getFormat().getFrameSize() != 0) {
                throw new IllegalArgumentException("illegal request to read "
                                                   +"non-integral number of frames ("
                                                   +len+" bytes, "
                                                   +"frameSize = "+getFormat().getFrameSize()+" bytes)");
            }
            if (off < 0) {
                throw new ArrayIndexOutOfBoundsException(off);
            }
            if ((long)off + (long)len > (long)b.length) {
                throw new ArrayIndexOutOfBoundsException(b.length);
            }
            synchronized(lock) {
                if (!isActive() && doIO) {
                    // this is not exactly correct... would be nicer
                    // if the native sub system sent a callback when IO really
                    // starts
                    setActive(true);
                    setStarted(true);
                }
            }
            int read = 0;
            while (doIO && !flushing) {
                int thisRead;
                synchronized (lockNative) {
                    thisRead = nRead(id, b, off, len, softwareConversionSize);
                    if (thisRead < 0) {
                        // error in native layer
                        break;
                    }
                    bytePosition += thisRead;
                    if (thisRead > 0) {
                        drained = false;
                    }
                }
                len -= thisRead;
                read += thisRead;
                if (len > 0) {
                    off += thisRead;
                    synchronized(lock) {
                        try {
                            lock.wait(waitTime);
                        } catch (InterruptedException ie) {}
                    }
                } else {
                    break;
                }
            }
            if (flushing) {
                read = 0;
            }
            return read;
        }

    }

    
Private inner class representing a Clip
This clip is realized in software only
/**
     * Private inner class representing a Clip
     * This clip is realized in software only
     */
    private static final class DirectClip extends DirectDL
            implements Clip, Runnable, AutoClosingClip {

        private volatile Thread thread;
        private volatile byte[] audioData = null;
        private volatile int frameSize;         // size of one frame in bytes
        private volatile int m_lengthInFrames;
        private volatile int loopCount;
        private volatile int clipBytePosition;   // index in the audioData array at current playback
        private volatile int newFramePosition;   // set in setFramePosition()
        private volatile int loopStartFrame;
        private volatile int loopEndFrame;      // the last sample included in the loop

        // auto closing clip support
        private boolean autoclosing = false;

        private DirectClip(DataLine.Info info,
                           AudioFormat format,
                           int bufferSize,
                           DirectAudioDevice mixer) {
            super(info, mixer, format, bufferSize, mixer.getMixerIndex(), mixer.getDeviceID(), true);
        }

        // CLIP METHODS

        @Override
        public void open(AudioFormat format, byte[] data, int offset, int bufferSize)
            throws LineUnavailableException {

            // $$fb part of fix for 4679187: Clip.open() throws unexpected Exceptions
            Toolkit.isFullySpecifiedAudioFormat(format);
            Toolkit.validateBuffer(format.getFrameSize(), bufferSize);

            byte[] newData = new byte[bufferSize];
            System.arraycopy(data, offset, newData, 0, bufferSize);
            open(format, newData, bufferSize / format.getFrameSize());
        }

        // this method does not copy the data array
        private void open(AudioFormat format, byte[] data, int frameLength)
            throws LineUnavailableException {

            // $$fb part of fix for 4679187: Clip.open() throws unexpected Exceptions
            Toolkit.isFullySpecifiedAudioFormat(format);

            synchronized (mixer) {
                if (isOpen()) {
                    throw new IllegalStateException("Clip is already open with format " + getFormat() +
                                                    " and frame lengh of " + getFrameLength());
                } else {
                    // if the line is not currently open, try to open it with this format and buffer size
                    this.audioData = data;
                    this.frameSize = format.getFrameSize();
                    this.m_lengthInFrames = frameLength;
                    // initialize loop selection with full range
                    bytePosition = 0;
                    clipBytePosition = 0;
                    newFramePosition = -1; // means: do not set to a new readFramePos
                    loopStartFrame = 0;
                    loopEndFrame = frameLength - 1;
                    loopCount = 0; // means: play the clip irrespective of loop points from beginning to end

                    try {
                        // use DirectDL's open method to open it
                        open(format, (int) Toolkit.millis2bytes(format, CLIP_BUFFER_TIME)); // one second buffer
                    } catch (LineUnavailableException lue) {
                        audioData = null;
                        throw lue;
                    } catch (IllegalArgumentException iae) {
                        audioData = null;
                        throw iae;
                    }

                    // if we got this far, we can instanciate the thread
                    int priority = Thread.NORM_PRIORITY
                        + (Thread.MAX_PRIORITY - Thread.NORM_PRIORITY) / 3;
                    thread = JSSecurityManager.createThread(this,
                                                            "Direct Clip", // name
                                                            true,     // daemon
                                                            priority, // priority
                                                            false);  // doStart
                    // cannot start in createThread, because the thread
                    // uses the "thread" variable as indicator if it should
                    // continue to run
                    thread.start();
                }
            }
            if (isAutoClosing()) {
                getEventDispatcher().autoClosingClipOpened(this);
            }
        }

        @Override
        public void open(AudioInputStream stream) throws LineUnavailableException, IOException {

            // $$fb part of fix for 4679187: Clip.open() throws unexpected Exceptions
            Toolkit.isFullySpecifiedAudioFormat(stream.getFormat());

            synchronized (mixer) {
                byte[] streamData = null;

                if (isOpen()) {
                    throw new IllegalStateException("Clip is already open with format " + getFormat() +
                                                    " and frame lengh of " + getFrameLength());
                }
                int lengthInFrames = (int)stream.getFrameLength();
                int bytesRead = 0;
                int frameSize = stream.getFormat().getFrameSize();
                if (lengthInFrames != AudioSystem.NOT_SPECIFIED) {
                    // read the data from the stream into an array in one fell swoop.
                    int arraysize = lengthInFrames * frameSize;
                    if (arraysize < 0) {
                        throw new IllegalArgumentException("Audio data < 0");
                    }
                    try {
                        streamData = new byte[arraysize];
                    } catch (OutOfMemoryError e) {
                        throw new IOException("Audio data is too big");
                    }
                    int bytesRemaining = arraysize;
                    int thisRead = 0;
                    while (bytesRemaining > 0 && thisRead >= 0) {
                        thisRead = stream.read(streamData, bytesRead, bytesRemaining);
                        if (thisRead > 0) {
                            bytesRead += thisRead;
                            bytesRemaining -= thisRead;
                        }
                        else if (thisRead == 0) {
                            Thread.yield();
                        }
                    }
                } else {
                    // read data from the stream until we reach the end of the stream
                    // we use a slightly modified version of ByteArrayOutputStream
                    // to get direct access to the byte array (we don't want a new array
                    // to be allocated)
                    int maxReadLimit = Math.max(16384, frameSize);
                    DirectBAOS dbaos  = new DirectBAOS();
                    byte[] tmp;
                    try {
                        tmp = new byte[maxReadLimit];
                    } catch (OutOfMemoryError e) {
                        throw new IOException("Audio data is too big");
                    }
                    int thisRead = 0;
                    while (thisRead >= 0) {
                        thisRead = stream.read(tmp, 0, tmp.length);
                        if (thisRead > 0) {
                            dbaos.write(tmp, 0, thisRead);
                            bytesRead += thisRead;
                        }
                        else if (thisRead == 0) {
                            Thread.yield();
                        }
                    } // while
                    streamData = dbaos.getInternalBuffer();
                }
                lengthInFrames = bytesRead / frameSize;

                // now try to open the device
                open(stream.getFormat(), streamData, lengthInFrames);
            } // synchronized
        }

        @Override
        public int getFrameLength() {
            return m_lengthInFrames;
        }

        @Override
        public long getMicrosecondLength() {
            return Toolkit.frames2micros(getFormat(), getFrameLength());
        }

        @Override
        public void setFramePosition(int frames) {
            if (frames < 0) {
                frames = 0;
            }
            else if (frames >= getFrameLength()) {
                frames = getFrameLength();
            }
            if (doIO) {
                newFramePosition = frames;
            } else {
                clipBytePosition = frames * frameSize;
                newFramePosition = -1;
            }
            // fix for failing test050
            // $$fb although getFramePosition should return the number of rendered
            // frames, it is intuitive that setFramePosition will modify that
            // value.
            bytePosition = frames * frameSize;

            // cease currently playing buffer
            flush();

            // set new native position (if necessary)
            // this must come after the flush!
            synchronized (lockNative) {
                nSetBytePosition(id, isSource, frames * frameSize);
            }
        }

        // replacement for getFramePosition (see AbstractDataLine)
        @Override
        public long getLongFramePosition() {
            /* $$fb
             * this would be intuitive, but the definition of getFramePosition
             * is the number of frames rendered since opening the device...
             * That also means that setFramePosition() means something very
             * different from getFramePosition() for Clip.
             */
            // take into account the case that a new position was set...
            //if (!doIO && newFramePosition >= 0) {
            //return newFramePosition;
            //}
            return super.getLongFramePosition();
        }

        @Override
        public synchronized void setMicrosecondPosition(long microseconds) {
            long frames = Toolkit.micros2frames(getFormat(), microseconds);
            setFramePosition((int) frames);
        }

        @Override
        public void setLoopPoints(int start, int end) {
            if (start < 0 || start >= getFrameLength()) {
                throw new IllegalArgumentException("illegal value for start: "+start);
            }
            if (end >= getFrameLength()) {
                throw new IllegalArgumentException("illegal value for end: "+end);
            }

            if (end == -1) {
                end = getFrameLength() - 1;
                if (end < 0) {
                    end = 0;
                }
            }

            // if the end position is less than the start position, throw IllegalArgumentException
            if (end < start) {
                throw new IllegalArgumentException("End position " + end + "  preceeds start position " + start);
            }

            // slight race condition with the run() method, but not a big problem
            loopStartFrame = start;
            loopEndFrame = end;
        }

        @Override
        public void loop(int count) {
            // note: when count reaches 0, it means that the entire clip
            // will be played, i.e. it will play past the loop end point
            loopCount = count;
            start();
        }

        @Override
        void implOpen(AudioFormat format, int bufferSize) throws LineUnavailableException {
            // only if audioData wasn't set in a calling open(format, byte[], frameSize)
            // this call is allowed.
            if (audioData == null) {
                throw new IllegalArgumentException("illegal call to open() in interface Clip");
            }
            super.implOpen(format, bufferSize);
        }

        @Override
        void implClose() {
            // dispose of thread
            Thread oldThread = thread;
            thread = null;
            doIO = false;
            if (oldThread != null) {
                // wake up the thread if it's in wait()
                synchronized(lock) {
                    lock.notifyAll();
                }
                // wait for the thread to terminate itself,
                // but max. 2 seconds. Must not be synchronized!
                try {
                    oldThread.join(2000);
                } catch (InterruptedException ie) {}
            }
            super.implClose();
            // remove audioData reference and hand it over to gc
            audioData = null;
            newFramePosition = -1;

            // remove this instance from the list of auto closing clips
            getEventDispatcher().autoClosingClipClosed(this);
        }

        @Override
        void implStart() {
            super.implStart();
        }

        @Override
        void implStop() {
            super.implStop();
            // reset loopCount field so that playback will be normal with
            // next call to start()
            loopCount = 0;
        }

        // main playback loop
        @Override
        public void run() {
            Thread curThread = Thread.currentThread();
            while (thread == curThread) {
                // doIO is volatile, but we could check it, then get
                // pre-empted while another thread changes doIO and notifies,
                // before we wait (so we sleep in wait forever).
                synchronized(lock) {
                    while (!doIO && thread == curThread) {
                        try {
                            lock.wait();
                        } catch (InterruptedException ignored) {
                        }
                    }
                }
                while (doIO && thread == curThread) {
                    if (newFramePosition >= 0) {
                        clipBytePosition = newFramePosition * frameSize;
                        newFramePosition = -1;
                    }
                    int endFrame = getFrameLength() - 1;
                    if (loopCount > 0 || loopCount == LOOP_CONTINUOUSLY) {
                        endFrame = loopEndFrame;
                    }
                    long framePos = (clipBytePosition / frameSize);
                    int toWriteFrames = (int) (endFrame - framePos + 1);
                    int toWriteBytes = toWriteFrames * frameSize;
                    if (toWriteBytes > getBufferSize()) {
                        toWriteBytes = Toolkit.align(getBufferSize(), frameSize);
                    }
                    int written = write(audioData, clipBytePosition, toWriteBytes); // increases bytePosition
                    clipBytePosition += written;
                    // make sure nobody called setFramePosition, or stop() during the write() call
                    if (doIO && newFramePosition < 0 && written >= 0) {
                        framePos = clipBytePosition / frameSize;
                        // since endFrame is the last frame to be played,
                        // framePos is after endFrame when all frames, including framePos,
                        // are played.
                        if (framePos > endFrame) {
                            // at end of playback. If looping is on, loop back to the beginning.
                            if (loopCount > 0 || loopCount == LOOP_CONTINUOUSLY) {
                                if (loopCount != LOOP_CONTINUOUSLY) {
                                    loopCount--;
                                }
                                newFramePosition = loopStartFrame;
                            } else {
                                // no looping, stop playback
                                drain();
                                stop();
                            }
                        }
                    }
                }
            }
        }

        // AUTO CLOSING CLIP SUPPORT

        /* $$mp 2003-10-01
           The following two methods are common between this class and
           MixerClip. They should be moved to a base class, together
           with the instance variable 'autoclosing'. */

        @Override
        public boolean isAutoClosing() {
            return autoclosing;
        }

        @Override
        public void setAutoClosing(boolean value) {
            if (value != autoclosing) {
                if (isOpen()) {
                    if (value) {
                        getEventDispatcher().autoClosingClipOpened(this);
                    } else {
                        getEventDispatcher().autoClosingClipClosed(this);
                    }
                }
                autoclosing = value;
            }
        }

        @Override
        protected boolean requiresServicing() {
            // no need for servicing for Clips
            return false;
        }

    } // DirectClip

    /*
     * private inner class representing a ByteArrayOutputStream
     * which allows retrieval of the internal array
     */
    private static class DirectBAOS extends ByteArrayOutputStream {
        DirectBAOS() {
            super();
        }

        public byte[] getInternalBuffer() {
            return buf;
        }

    } // class DirectBAOS

    @SuppressWarnings("rawtypes")
    private static native void nGetFormats(int mixerIndex, int deviceID,
                                           boolean isSource, Vector formats);

    private static native long nOpen(int mixerIndex, int deviceID, boolean isSource,
                                     int encoding,
                                     float sampleRate,
                                     int sampleSizeInBits,
                                     int frameSize,
                                     int channels,
                                     boolean signed,
                                     boolean bigEndian,
                                     int bufferSize) throws LineUnavailableException;
    private static native void nStart(long id, boolean isSource);
    private static native void nStop(long id, boolean isSource);
    private static native void nClose(long id, boolean isSource);
    private static native int nWrite(long id, byte[] b, int off, int len, int conversionSize,
                                     float volLeft, float volRight);
    private static native int nRead(long id, byte[] b, int off, int len, int conversionSize);
    private static native int nGetBufferSize(long id, boolean isSource);
    private static native boolean nIsStillDraining(long id, boolean isSource);
    private static native void nFlush(long id, boolean isSource);
    private static native int nAvailable(long id, boolean isSource);
    // javaPos is number of bytes read/written in Java layer
    private static native long nGetBytePosition(long id, boolean isSource, long javaPos);
    private static native void nSetBytePosition(long id, boolean isSource, long pos);

    // returns if the native implementation needs regular calls to nService()
    private static native boolean nRequiresServicing(long id, boolean isSource);
    // called in irregular intervals
    private static native void nService(long id, boolean isSource);
}