/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 */
package sun.awt.image;

import java.awt.image.*;
import java.io.InputStream;
import java.io.IOException;
import java.io.BufferedInputStream;
import java.util.Hashtable;

public abstract class InputStreamImageSource implements ImageProducer, ImageFetchable {

    ImageConsumerQueue consumers;

    ImageDecoder decoder;

    ImageDecoder decoders;

    boolean awaitingFetch = false;

    abstract boolean checkSecurity(Object context, boolean quiet);

    int countConsumers(ImageConsumerQueue cq) {
        int i = 0;
        while (cq != null) {
            i++;
            cq = cq.next;
        }
        return i;
    }

    synchronized int countConsumers() {
        ImageDecoder id = decoders;
        int i = countConsumers(consumers);
        while (id != null) {
            i += countConsumers(id.queue);
            id = id.next;
        }
        return i;
    }

    public void addConsumer(ImageConsumer ic) {
        addConsumer(ic, false);
    }

    synchronized void printQueue(ImageConsumerQueue cq, String prefix) {
        while (cq != null) {
            System.out.println(prefix + cq);
            cq = cq.next;
        }
    }

    synchronized void printQueues(String title) {
        System.out.println(title + "[ -----------");
        printQueue(consumers, "  ");
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            System.out.println("    " + id);
            printQueue(id.queue, "      ");
        }
        System.out.println("----------- ]" + title);
    }

    synchronized void addConsumer(ImageConsumer ic, boolean produce) {
        checkSecurity(null, false);
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                // This consumer is already being fed.
                return;
            }
        }
        ImageConsumerQueue cq = consumers;
        while (cq != null && cq.consumer != ic) {
            cq = cq.next;
        }
        if (cq == null) {
            cq = new ImageConsumerQueue(this, ic);
            cq.next = consumers;
            consumers = cq;
        } else {
            if (!cq.secure) {
                Object context = null;
                SecurityManager security = System.getSecurityManager();
                if (security != null) {
                    context = security.getSecurityContext();
                }
                if (cq.securityContext == null) {
                    cq.securityContext = context;
                } else if (!cq.securityContext.equals(context)) {
                    // If there are two different security contexts that both
                    // have a handle on the same ImageConsumer, then there has
                    // been a security breach and whether or not they trade
                    // image data is small fish compared to what they could be
                    // trading.  Throw a Security exception anyway...
                    errorConsumer(cq, false);
                    throw new SecurityException("Applets are trading image data!");
                }
            }
            cq.interested = true;
        }
        if (produce && decoder == null) {
            startProduction();
        }
    }

    public synchronized boolean isConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                return true;
            }
        }
        return ImageConsumerQueue.isConsumer(consumers, ic);
    }

    private void errorAllConsumers(ImageConsumerQueue cq, boolean needReload) {
        while (cq != null) {
            if (cq.interested) {
                errorConsumer(cq, needReload);
            }
            cq = cq.next;
        }
    }

    private void errorConsumer(ImageConsumerQueue cq, boolean needReload) {
        cq.consumer.imageComplete(ImageConsumer.IMAGEERROR);
        if (needReload && cq.consumer instanceof ImageRepresentation) {
            ((ImageRepresentation) cq.consumer).image.flush();
        }
        removeConsumer(cq.consumer);
    }

    public synchronized void removeConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            id.removeConsumer(ic);
        }
        consumers = ImageConsumerQueue.removeConsumer(consumers, ic, false);
    }

    public void startProduction(ImageConsumer ic) {
        addConsumer(ic, true);
    }

    private synchronized void startProduction() {
        if (!awaitingFetch) {
            ImageFetcher.add(this);
            awaitingFetch = true;
        }
    }

    private synchronized void stopProduction() {
        if (awaitingFetch) {
            ImageFetcher.remove(this);
            awaitingFetch = false;
        }
    }

    public void requestTopDownLeftRightResend(ImageConsumer ic) {
    }

    protected abstract ImageDecoder getDecoder();

    protected ImageDecoder decoderForType(InputStream is, String content_type) {
        // Don't believe the content type - file extensions can
        return null;
    }

    protected ImageDecoder getDecoder(InputStream is) {
        if (!is.markSupported())
            is = new BufferedInputStream(is);
        try {
            /* changed to support png
             is.mark(6);
             */
            is.mark(8);
            int c1 = is.read();
            int c2 = is.read();
            int c3 = is.read();
            int c4 = is.read();
            int c5 = is.read();
            int c6 = is.read();
            // added to support png
            int c7 = is.read();
            int c8 = is.read();
            // end of adding
            is.reset();
            is.mark(-1);
            if (c1 == 'G' && c2 == 'I' && c3 == 'F' && c4 == '8') {
                return new GifImageDecoder(this, is);
            } else if (c1 == '\377' && c2 == '\330' && c3 == '\377') {
                return new JPEGImageDecoder(this, is);
            } else if (c1 == '#' && c2 == 'd' && c3 == 'e' && c4 == 'f') {
                return new XbmImageDecoder(this, is);
                // added to support png
            } else if (c1 == 137 && c2 == 80 && c3 == 78 && c4 == 71 && c5 == 13 && c6 == 10 && c7 == 26 && c8 == 10) {
                return new PNGImageDecoder(this, is);
            }
            // end of adding
        } catch (IOException e) {
        }
        return null;
    }

    public void doFetch() {
        synchronized (this) {
            if (consumers == null) {
                awaitingFetch = false;
                return;
            }
        }
        ImageDecoder imgd = getDecoder();
        if (imgd == null) {
            badDecoder();
        } else {
            setDecoder(imgd);
            try {
                imgd.produceImage();
            } catch (IOException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } catch (ImageFormatException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } finally {
                removeDecoder(imgd);
                if (Thread.currentThread().isInterrupted() || !Thread.currentThread().isAlive()) {
                    errorAllConsumers(imgd.queue, true);
                } else {
                    errorAllConsumers(imgd.queue, false);
                }
            }
        }
    }

    private void badDecoder() {
        ImageConsumerQueue cq;
        synchronized (this) {
            cq = consumers;
            consumers = null;
            awaitingFetch = false;
        }
        errorAllConsumers(cq, false);
    }

    private void setDecoder(ImageDecoder mydecoder) {
        ImageConsumerQueue cq;
        synchronized (this) {
            mydecoder.next = decoders;
            decoders = mydecoder;
            decoder = mydecoder;
            cq = consumers;
            mydecoder.queue = cq;
            consumers = null;
            awaitingFetch = false;
        }
        while (cq != null) {
            if (cq.interested) {
                // Now that there is a decoder, security may have changed
                // so reverify it here, just in case.
                if (!checkSecurity(cq.securityContext, true)) {
                    errorConsumer(cq, false);
                }
            }
            cq = cq.next;
        }
    }

    private synchronized void removeDecoder(ImageDecoder mydecoder) {
        doneDecoding(mydecoder);
        ImageDecoder idprev = null;
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id == mydecoder) {
                if (idprev == null) {
                    decoders = id.next;
                } else {
                    idprev.next = id.next;
                }
                break;
            }
            idprev = id;
        }
    }

    synchronized void doneDecoding(ImageDecoder mydecoder) {
        if (decoder == mydecoder) {
            decoder = null;
            if (consumers != null) {
                startProduction();
            }
        }
    }

    void latchConsumers(ImageDecoder id)

    synchronized void flush() {
        decoder = null;
    }
}


/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 */
package sun.awt.image;

import java.awt.image.*;
import java.io.InputStream;
import java.io.IOException;
import java.io.BufferedInputStream;
import java.util.Hashtable;

public abstract class InputStreamImageSource implements ImageProducer, ImageFetchable {

    ImageConsumerQueue consumers;

    ImageDecoder decoder;

    ImageDecoder decoders;

    boolean awaitingFetch = false;

    abstract boolean checkSecurity(Object context, boolean quiet);

    int countConsumers(ImageConsumerQueue cq) {
        int i = 0;
        while (cq != null) {
            i++;
            cq = cq.next;
        }
        return i;
    }

    synchronized int countConsumers() {
        ImageDecoder id = decoders;
        int i = countConsumers(consumers);
        while (id != null) {
            i += countConsumers(id.queue);
            id = id.next;
        }
        return i;
    }

    public void addConsumer(ImageConsumer ic) {
        addConsumer(ic, false);
    }

    synchronized void printQueue(ImageConsumerQueue cq, String prefix) {
        while (cq != null) {
            System.out.println(prefix + cq);
            cq = cq.next;
        }
    }

    synchronized void printQueues(String title) {
        System.out.println(title + "[ -----------");
        printQueue(consumers, "  ");
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            System.out.println("    " + id);
            printQueue(id.queue, "      ");
        }
        System.out.println("----------- ]" + title);
    }

    synchronized void addConsumer(ImageConsumer ic, boolean produce) {
        checkSecurity(null, false);
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                // This consumer is already being fed.
                return;
            }
        }
        ImageConsumerQueue cq = consumers;
        while (cq != null && cq.consumer != ic) {
            cq = cq.next;
        }
        if (cq == null) {
            cq = new ImageConsumerQueue(this, ic);
            cq.next = consumers;
            consumers = cq;
        } else {
            if (!cq.secure) {
                Object context = null;
                SecurityManager security = System.getSecurityManager();
                if (security != null) {
                    context = security.getSecurityContext();
                }
                if (cq.securityContext == null) {
                    cq.securityContext = context;
                } else if (!cq.securityContext.equals(context)) {
                    // If there are two different security contexts that both
                    // have a handle on the same ImageConsumer, then there has
                    // been a security breach and whether or not they trade
                    // image data is small fish compared to what they could be
                    // trading.  Throw a Security exception anyway...
                    errorConsumer(cq, false);
                    throw new SecurityException("Applets are trading image data!");
                }
            }
            cq.interested = true;
        }
        if (produce && decoder == null) {
            startProduction();
        }
    }

    public synchronized boolean isConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                return true;
            }
        }
        return ImageConsumerQueue.isConsumer(consumers, ic);
    }

    private void errorAllConsumers(ImageConsumerQueue cq, boolean needReload) {
        while (cq != null) {
            if (cq.interested) {
                errorConsumer(cq, needReload);
            }
            cq = cq.next;
        }
    }

    private void errorConsumer(ImageConsumerQueue cq, boolean needReload) {
        cq.consumer.imageComplete(ImageConsumer.IMAGEERROR);
        if (needReload && cq.consumer instanceof ImageRepresentation) {
            ((ImageRepresentation) cq.consumer).image.flush();
        }
        removeConsumer(cq.consumer);
    }

    public synchronized void removeConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            id.removeConsumer(ic);
        }
        consumers = ImageConsumerQueue.removeConsumer(consumers, ic, false);
    }

    public void startProduction(ImageConsumer ic) {
        addConsumer(ic, true);
    }

    private synchronized void startProduction() {
        if (!awaitingFetch) {
            ImageFetcher.add(this);
            awaitingFetch = true;
        }
    }

    private synchronized void stopProduction() {
        if (awaitingFetch) {
            ImageFetcher.remove(this);
            awaitingFetch = false;
        }
    }

    public void requestTopDownLeftRightResend(ImageConsumer ic) {
    }

    protected abstract ImageDecoder getDecoder();

    protected ImageDecoder decoderForType(InputStream is, String content_type) {
        // Don't believe the content type - file extensions can
        return null;
    }

    protected ImageDecoder getDecoder(InputStream is) {
        if (!is.markSupported())
            is = new BufferedInputStream(is);
        try {
            /* changed to support png
             is.mark(6);
             */
            is.mark(8);
            int c1 = is.read();
            int c2 = is.read();
            int c3 = is.read();
            int c4 = is.read();
            int c5 = is.read();
            int c6 = is.read();
            // added to support png
            int c7 = is.read();
            int c8 = is.read();
            // end of adding
            is.reset();
            is.mark(-1);
            if (c1 == 'G' && c2 == 'I' && c3 == 'F' && c4 == '8') {
                return new GifImageDecoder(this, is);
            } else if (c1 == '\377' && c2 == '\330' && c3 == '\377') {
                return new JPEGImageDecoder(this, is);
            } else if (c1 == '#' && c2 == 'd' && c3 == 'e' && c4 == 'f') {
                return new XbmImageDecoder(this, is);
                // added to support png
            } else if (c1 == 137 && c2 == 80 && c3 == 78 && c4 == 71 && c5 == 13 && c6 == 10 && c7 == 26 && c8 == 10) {
                return new PNGImageDecoder(this, is);
            }
            // end of adding
        } catch (IOException e) {
        }
        return null;
    }

    public void doFetch() {
        synchronized (this) {
            if (consumers == null) {
                awaitingFetch = false;
                return;
            }
        }
        ImageDecoder imgd = getDecoder();
        if (imgd == null) {
            badDecoder();
        } else {
            setDecoder(imgd);
            try {
                imgd.produceImage();
            } catch (IOException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } catch (ImageFormatException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } finally {
                removeDecoder(imgd);
                if (Thread.currentThread().isInterrupted() || !Thread.currentThread().isAlive()) {
                    errorAllConsumers(imgd.queue, true);
                } else {
                    errorAllConsumers(imgd.queue, false);
                }
            }
        }
    }

    private void badDecoder() {

        synchronized (this) {
            cq = consumers;
            consumers = null;
            awaitingFetch = false;
        }
        errorAllConsumers(cq, false);
    }

    private void setDecoder(ImageDecoder mydecoder) {
        ImageConsumerQueue cq;
        synchronized (this) {
            mydecoder.next = decoders;
            decoders = mydecoder;
            decoder = mydecoder;
            cq = consumers;
            mydecoder.queue = cq;
            consumers = null;
            awaitingFetch = false;
        }
        while (cq != null) {
            if (cq.interested) {
                // Now that there is a decoder, security may have changed
                // so reverify it here, just in case.
                if (!checkSecurity(cq.securityContext, true)) {
                    errorConsumer(cq, false);
                }
            }
            cq = cq.next;
        }
    }

    private synchronized void removeDecoder(ImageDecoder mydecoder) {
        doneDecoding(mydecoder);
        ImageDecoder idprev = null;
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id == mydecoder) {
                if (idprev == null) {
                    decoders = id.next;
                } else {
                    idprev.next = id.next;
                }
                break;
            }
            idprev = id;
        }
    }

    synchronized void doneDecoding(ImageDecoder mydecoder) {
        if (decoder == mydecoder) {
            decoder = null;
            if (consumers != null) {
                startProduction();
            }
        }
    }

    void latchConsumers(ImageDecoder id) {
        doneDecoding(id);
    }

    synchronized void flush() {
        decoder = null;
    }
}


synchronized (this) {
            cq = consumers;
            consumers = null;
            awaitingFetch = false;
        }

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 */
package sun.awt.image;

import java.awt.image.*;
import java.io.InputStream;
import java.io.IOException;
import java.io.BufferedInputStream;
import java.util.Hashtable;

public abstract class InputStreamImageSource implements ImageProducer, ImageFetchable {

    ImageConsumerQueue consumers;

    ImageDecoder decoder;

    ImageDecoder decoders;

    boolean awaitingFetch = false;

    abstract boolean checkSecurity(Object context, boolean quiet);

    int countConsumers(ImageConsumerQueue cq) {
        int i = 0;
        while (cq != null) {
            i++;
            cq = cq.next;
        }
        return i;
    }

    synchronized int countConsumers() {
        ImageDecoder id = decoders;
        int i = countConsumers(consumers);
        while (id != null) {
            i += countConsumers(id.queue);
            id = id.next;
        }
        return i;
    }

    public void addConsumer(ImageConsumer ic) {
        addConsumer(ic, false);
    }

    synchronized void printQueue(ImageConsumerQueue cq, String prefix) {
        while (cq != null) {
            System.out.println(prefix + cq);
            cq = cq.next;
        }
    }

    synchronized void printQueues(String title) {
        System.out.println(title + "[ -----------");
        printQueue(consumers, "  ");
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            System.out.println("    " + id);
            printQueue(id.queue, "      ");
        }
        System.out.println("----------- ]" + title);
    }

    synchronized void addConsumer(ImageConsumer ic, boolean produce) {
        checkSecurity(null, false);
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                // This consumer is already being fed.
                return;
            }
        }
        ImageConsumerQueue cq = consumers;
        while (cq != null && cq.consumer != ic) {
            cq = cq.next;
        }
        if (cq == null) {
            cq = new ImageConsumerQueue(this, ic);
            cq.next = consumers;
            consumers = cq;
        } else {
            if (!cq.secure) {
                Object context = null;
                SecurityManager security = System.getSecurityManager();
                if (security != null) {
                    context = security.getSecurityContext();
                }
                if (cq.securityContext == null) {
                    cq.securityContext = context;
                } else if (!cq.securityContext.equals(context)) {
                    // If there are two different security contexts that both
                    // have a handle on the same ImageConsumer, then there has
                    // been a security breach and whether or not they trade
                    // image data is small fish compared to what they could be
                    // trading.  Throw a Security exception anyway...
                    errorConsumer(cq, false);
                    throw new SecurityException("Applets are trading image data!");
                }
            }
            cq.interested = true;
        }
        if (produce && decoder == null) {
            startProduction();
        }
    }

    public synchronized boolean isConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                return true;
            }
        }
        return ImageConsumerQueue.isConsumer(consumers, ic);
    }

    private void errorAllConsumers(ImageConsumerQueue cq, boolean needReload) {
        while (cq != null) {
            if (cq.interested) {
                errorConsumer(cq, needReload);
            }
            cq = cq.next;
        }
    }

    private void errorConsumer(ImageConsumerQueue cq, boolean needReload) {
        cq.consumer.imageComplete(ImageConsumer.IMAGEERROR);
        if (needReload && cq.consumer instanceof ImageRepresentation) {
            ((ImageRepresentation) cq.consumer).image.flush();
        }
        removeConsumer(cq.consumer);
    }

    public synchronized void removeConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            id.removeConsumer(ic);
        }
        consumers = ImageConsumerQueue.removeConsumer(consumers, ic, false);
    }

    public void startProduction(ImageConsumer ic) {
        addConsumer(ic, true);
    }

    private synchronized void startProduction() {
        if (!awaitingFetch) {
            ImageFetcher.add(this);
            awaitingFetch = true;
        }
    }

    private synchronized void stopProduction() {
        if (awaitingFetch) {
            ImageFetcher.remove(this);
            awaitingFetch = false;
        }
    }

    public void requestTopDownLeftRightResend(ImageConsumer ic) {
    }

    protected abstract ImageDecoder getDecoder();

    protected ImageDecoder decoderForType(InputStream is, String content_type) {
        // Don't believe the content type - file extensions can
        return null;
    }

    protected ImageDecoder getDecoder(InputStream is) {
        if (!is.markSupported())
            is = new BufferedInputStream(is);
        try {
            /* changed to support png
             is.mark(6);
             */
            is.mark(8);
            int c1 = is.read();
            int c2 = is.read();
            int c3 = is.read();
            int c4 = is.read();
            int c5 = is.read();
            int c6 = is.read();
            // added to support png
            int c7 = is.read();
            int c8 = is.read();
            // end of adding
            is.reset();
            is.mark(-1);
            if (c1 == 'G' && c2 == 'I' && c3 == 'F' && c4 == '8') {
                return new GifImageDecoder(this, is);
            } else if (c1 == '\377' && c2 == '\330' && c3 == '\377') {
                return new JPEGImageDecoder(this, is);
            } else if (c1 == '#' && c2 == 'd' && c3 == 'e' && c4 == 'f') {
                return new XbmImageDecoder(this, is);
                // added to support png
            } else if (c1 == 137 && c2 == 80 && c3 == 78 && c4 == 71 && c5 == 13 && c6 == 10 && c7 == 26 && c8 == 10) {
                return new PNGImageDecoder(this, is);
            }
            // end of adding
        } catch (IOException e) {
        }
        return null;
    }

    public void doFetch() {
        synchronized (this) {
            if (consumers == null) {
                awaitingFetch = false;
                return;
            }
        }
        ImageDecoder imgd = getDecoder();
        if (imgd == null) {
            badDecoder();
        } else {
            setDecoder(imgd);
            try {
                imgd.produceImage();
            } catch (IOException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } catch (ImageFormatException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } finally {
                removeDecoder(imgd);
                if (Thread.currentThread().isInterrupted() || !Thread.currentThread().isAlive()) {
                    errorAllConsumers(imgd.queue, true);
                } else {
                    errorAllConsumers(imgd.queue, false);
                }
            }
        }
    }

    private void badDecoder() {
        ImageConsumerQueue cq;

        errorAllConsumers(cq, false);
    }

    private void setDecoder(ImageDecoder mydecoder) {
        ImageConsumerQueue cq;
        synchronized (this) {
            mydecoder.next = decoders;
            decoders = mydecoder;
            decoder = mydecoder;
            cq = consumers;
            mydecoder.queue = cq;
            consumers = null;
            awaitingFetch = false;
        }
        while (cq != null) {
            if (cq.interested) {
                // Now that there is a decoder, security may have changed
                // so reverify it here, just in case.
                if (!checkSecurity(cq.securityContext, true)) {
                    errorConsumer(cq, false);
                }
            }
            cq = cq.next;
        }
    }

    private synchronized void removeDecoder(ImageDecoder mydecoder) {
        doneDecoding(mydecoder);
        ImageDecoder idprev = null;
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id == mydecoder) {
                if (idprev == null) {
                    decoders = id.next;
                } else {
                    idprev.next = id.next;
                }
                break;
            }
            idprev = id;
        }
    }

    synchronized void doneDecoding(ImageDecoder mydecoder) {
        if (decoder == mydecoder) {
            decoder = null;
            if (consumers != null) {
                startProduction();
            }
        }
    }

    void latchConsumers(ImageDecoder id) {
        doneDecoding(id);
    }

    synchronized void flush() {
        decoder = null;
    }
}


/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 */
package sun.awt.image;

import java.awt.image.*;
import java.io.InputStream;
import java.io.IOException;
import java.io.BufferedInputStream;
import java.util.Hashtable;

public abstract class InputStreamImageSource implements ImageProducer, ImageFetchable {

    ImageConsumerQueue consumers;

    ImageDecoder decoder;

    ImageDecoder decoders;

    boolean awaitingFetch = false;

    abstract boolean checkSecurity(Object context, boolean quiet);

    int countConsumers(ImageConsumerQueue cq) {
        int i = 0;
        while (cq != null) {
            i++;
            cq = cq.next;
        }
        return i;
    }

    synchronized int countConsumers() {
        ImageDecoder id = decoders;
        int i = countConsumers(consumers);
        while (id != null) {
            i += countConsumers(id.queue);
            id = id.next;
        }
        return i;
    }

    public void addConsumer(ImageConsumer ic) {
        addConsumer(ic, false);
    }

    synchronized void printQueue(ImageConsumerQueue cq, String prefix) {
        while (cq != null) {
            System.out.println(prefix + cq);
            cq = cq.next;
        }
    }

    synchronized void printQueues(String title) {
        System.out.println(title + "[ -----------");
        printQueue(consumers, "  ");
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            System.out.println("    " + id);
            printQueue(id.queue, "      ");
        }
        System.out.println("----------- ]" + title);
    }

    synchronized void addConsumer(ImageConsumer ic, boolean produce) {
        checkSecurity(null, false);
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                // This consumer is already being fed.
                return;
            }
        }
        ImageConsumerQueue cq = consumers;
        while (cq != null && cq.consumer != ic) {
            cq = cq.next;
        }
        if (cq == null) {
            cq = new ImageConsumerQueue(this, ic);
            cq.next = consumers;
            consumers = cq;
        } else {
            if (!cq.secure) {
                Object context = null;
                SecurityManager security = System.getSecurityManager();
                if (security != null) {
                    context = security.getSecurityContext();
                }
                if (cq.securityContext == null) {
                    cq.securityContext = context;
                } else if (!cq.securityContext.equals(context)) {
                    // If there are two different security contexts that both
                    // have a handle on the same ImageConsumer, then there has
                    // been a security breach and whether or not they trade
                    // image data is small fish compared to what they could be
                    // trading.  Throw a Security exception anyway...
                    errorConsumer(cq, false);
                    throw new SecurityException("Applets are trading image data!");
                }
            }
            cq.interested = true;
        }
        if (produce && decoder == null) {
            startProduction();
        }
    }

    public synchronized boolean isConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                return true;
            }
        }
        return ImageConsumerQueue.isConsumer(consumers, ic);
    }

    private void errorAllConsumers(ImageConsumerQueue cq, boolean needReload) {
        while (cq != null) {
            if (cq.interested) {
                errorConsumer(cq, needReload);
            }
            cq = cq.next;
        }
    }

    private void errorConsumer(ImageConsumerQueue cq, boolean needReload) {
        cq.consumer.imageComplete(ImageConsumer.IMAGEERROR);
        if (needReload && cq.consumer instanceof ImageRepresentation) {
            ((ImageRepresentation) cq.consumer).image.flush();
        }
        removeConsumer(cq.consumer);
    }

    public synchronized void removeConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            id.removeConsumer(ic);
        }
        consumers = ImageConsumerQueue.removeConsumer(consumers, ic, false);
    }

    public void startProduction(ImageConsumer ic) {
        addConsumer(ic, true);
    }

    private synchronized void startProduction() {
        if (!awaitingFetch) {
            ImageFetcher.add(this);
            awaitingFetch = true;
        }
    }

    private synchronized void stopProduction() {
        if (awaitingFetch) {
            ImageFetcher.remove(this);
            awaitingFetch = false;
        }
    }

    public void requestTopDownLeftRightResend(ImageConsumer ic) {
    }

    protected abstract ImageDecoder getDecoder();

    protected ImageDecoder decoderForType(InputStream is, String content_type) {
        // Don't believe the content type - file extensions can
        return null;
    }

    protected ImageDecoder getDecoder(InputStream is) {
        if (!is.markSupported())
            is = new BufferedInputStream(is);
        try {
            /* changed to support png
             is.mark(6);
             */
            is.mark(8);
            int c1 = is.read();
            int c2 = is.read();
            int c3 = is.read();
            int c4 = is.read();
            int c5 = is.read();
            int c6 = is.read();
            // added to support png
            int c7 = is.read();
            int c8 = is.read();
            // end of adding
            is.reset();
            is.mark(-1);
            if (c1 == 'G' && c2 == 'I' && c3 == 'F' && c4 == '8') {
                return new GifImageDecoder(this, is);
            } else if (c1 == '\377' && c2 == '\330' && c3 == '\377') {
                return new JPEGImageDecoder(this, is);
            } else if (c1 == '#' && c2 == 'd' && c3 == 'e' && c4 == 'f') {
                return new XbmImageDecoder(this, is);
                // added to support png
            } else if (c1 == 137 && c2 == 80 && c3 == 78 && c4 == 71 && c5 == 13 && c6 == 10 && c7 == 26 && c8 == 10) {
                return new PNGImageDecoder(this, is);
            }
            // end of adding
        } catch (IOException e) {
        }
        return null;
    }

    public void doFetch() {
        synchronized (this) {
            if (consumers == null) {
                awaitingFetch = false;
                return;
            }
        }
        ImageDecoder imgd = getDecoder();
        if (imgd == null) {
            badDecoder();
        } else {
            setDecoder(imgd);
            try {
                imgd.produceImage();
            } catch (IOException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } catch (ImageFormatException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } finally {
                removeDecoder(imgd);
                if (Thread.currentThread().isInterrupted() || !Thread.currentThread().isAlive()) {
                    errorAllConsumers(imgd.queue, true);
                } else {
                    errorAllConsumers(imgd.queue, false);
                }
            }
        }
    }

    private void badDecoder() {
        ImageConsumerQueue cq;
        synchronized (this) {
            cq = consumers;
            consumers = null;
            awaitingFetch = false;
        }

    private void setDecoder(ImageDecoder mydecoder) {
        ImageConsumerQueue cq;
        synchronized (this) {
            mydecoder.next = decoders;
            decoders = mydecoder;
            decoder = mydecoder;
            cq = consumers;
            mydecoder.queue = cq;
            consumers = null;
            awaitingFetch = false;
        }
        while (cq != null) {
            if (cq.interested) {
                // Now that there is a decoder, security may have changed
                // so reverify it here, just in case.
                if (!checkSecurity(cq.securityContext, true)) {
                    errorConsumer(cq, false);
                }
            }
            cq = cq.next;
        }
    }

    private synchronized void removeDecoder(ImageDecoder mydecoder) {
        doneDecoding(mydecoder);
        ImageDecoder idprev = null;
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id == mydecoder) {
                if (idprev == null) {
                    decoders = id.next;
                } else {
                    idprev.next = id.next;
                }
                break;
            }
            idprev = id;
        }
    }

    synchronized void doneDecoding(ImageDecoder mydecoder) {
        if (decoder == mydecoder) {
            decoder = null;
            if (consumers != null) {
                startProduction();
            }
        }
    }

    void latchConsumers(ImageDecoder id) {
        doneDecoding(id);
    }

    synchronized void flush() {
        decoder = null;
    }
}


/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 */
package sun.awt.image;

import java.awt.image.*;
import java.io.InputStream;
import java.io.IOException;
import java.io.BufferedInputStream;
import java.util.Hashtable;

public abstract class InputStreamImageSource implements ImageProducer, ImageFetchable {

    ImageConsumerQueue consumers;

    ImageDecoder decoder;

    ImageDecoder decoders;

    boolean awaitingFetch = false;

    abstract boolean checkSecurity(Object context, boolean quiet);

    int countConsumers(ImageConsumerQueue cq) {
        int i = 0;
        while (cq != null) {
            i++;
            cq = cq.next;
        }
        return i;
    }

    synchronized int countConsumers() {
        ImageDecoder id = decoders;
        int i = countConsumers(consumers);
        while (id != null) {
            i += countConsumers(id.queue);
            id = id.next;
        }
        return i;
    }

    public void addConsumer(ImageConsumer ic) {
        addConsumer(ic, false);
    }

    synchronized void printQueue(ImageConsumerQueue cq, String prefix) {
        while (cq != null) {
            System.out.println(prefix + cq);
            cq = cq.next;
        }
    }

    synchronized void printQueues(String title) {
        System.out.println(title + "[ -----------");
        printQueue(consumers, "  ");
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            System.out.println("    " + id);
            printQueue(id.queue, "      ");
        }
        System.out.println("----------- ]" + title);
    }

    synchronized void addConsumer(ImageConsumer ic, boolean produce) {
        checkSecurity(null, false);
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                // This consumer is already being fed.
                return;
            }
        }
        ImageConsumerQueue cq = consumers;
        while (cq != null && cq.consumer != ic) {
            cq = cq.next;
        }
        if (cq == null) {
            cq = new ImageConsumerQueue(this, ic);
            cq.next = consumers;
            consumers = cq;
        } else {
            if (!cq.secure) {
                Object context = null;
                SecurityManager security = System.getSecurityManager();
                if (security != null) {
                    context = security.getSecurityContext();
                }
                if (cq.securityContext == null) {
                    cq.securityContext = context;
                } else if (!cq.securityContext.equals(context)) {
                    // If there are two different security contexts that both
                    // have a handle on the same ImageConsumer, then there has
                    // been a security breach and whether or not they trade
                    // image data is small fish compared to what they could be
                    // trading.  Throw a Security exception anyway...
                    errorConsumer(cq, false);
                    throw new SecurityException("Applets are trading image data!");
                }
            }
            cq.interested = true;
        }
        if (produce && decoder == null) {
            startProduction();
        }
    }

    public synchronized boolean isConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                return true;
            }
        }
        return ImageConsumerQueue.isConsumer(consumers, ic);
    }

    private void errorAllConsumers(ImageConsumerQueue cq, boolean needReload) {
        while (cq != null) {
            if (cq.interested) {
                errorConsumer(cq, needReload);
            }
            cq = cq.next;
        }
    }

    private void errorConsumer(ImageConsumerQueue cq, boolean needReload) {
        cq.consumer.imageComplete(ImageConsumer.IMAGEERROR);
        if (needReload && cq.consumer instanceof ImageRepresentation) {
            ((ImageRepresentation) cq.consumer).image.flush();
        }
        removeConsumer(cq.consumer);
    }

    public synchronized void removeConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            id.removeConsumer(ic);
        }
        consumers = ImageConsumerQueue.removeConsumer(consumers, ic, false);
    }

    public void startProduction(ImageConsumer ic) {
        addConsumer(ic, true);
    }

    private synchronized void startProduction() {
        if (!awaitingFetch) {
            ImageFetcher.add(this);
            awaitingFetch = true;
        }
    }

    private synchronized void stopProduction() {
        if (awaitingFetch) {
            ImageFetcher.remove(this);
            awaitingFetch = false;
        }
    }

    public void requestTopDownLeftRightResend(ImageConsumer ic) {
    }

    protected abstract ImageDecoder getDecoder();

    protected ImageDecoder decoderForType(InputStream is, String content_type) {
        // Don't believe the content type - file extensions can
        return null;
    }

    protected ImageDecoder getDecoder(InputStream is) {
        if (!is.markSupported())
            is = new BufferedInputStream(is);
        try {
            /* changed to support png
             is.mark(6);
             */
            is.mark(8);
            int c1 = is.read();
            int c2 = is.read();
            int c3 = is.read();
            int c4 = is.read();
            int c5 = is.read();
            int c6 = is.read();
            // added to support png
            int c7 = is.read();
            int c8 = is.read();
            // end of adding
            is.reset();
            is.mark(-1);
            if (c1 == 'G' && c2 == 'I' && c3 == 'F' && c4 == '8') {
                return new GifImageDecoder(this, is);
            } else if (c1 == '\377' && c2 == '\330' && c3 == '\377') {
                return new JPEGImageDecoder(this, is);
            } else if (c1 == '#' && c2 == 'd' && c3 == 'e' && c4 == 'f') {
                return new XbmImageDecoder(this, is);
                // added to support png
            } else if (c1 == 137 && c2 == 80 && c3 == 78 && c4 == 71 && c5 == 13 && c6 == 10 && c7 == 26 && c8 == 10) {
                return new PNGImageDecoder(this, is);
            }
            // end of adding
        } catch (IOException e) {
        }
        return null;
    }

    public void doFetch() {
        synchronized (this) {
            if (consumers == null) {
                awaitingFetch = false;
                return;
            }
        }
        ImageDecoder imgd = getDe

        if (imgd == null) {
            badDecoder();
        } else {
            setDecoder(imgd);
            try {
                imgd.produceImage();
            } catch (IOException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } catch (ImageFormatException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } finally {
                removeDecoder(imgd);
                if (Thread.currentThread().isInterrupted() || !Thread.currentThread().isAlive()) {
                    errorAllConsumers(imgd.queue, true);
                } else {
                    errorAllConsumers(imgd.queue, false);
                }
            }
        }
    }

    private void badDecoder() {
        ImageConsumerQueue cq;
        synchronized (this) {
            cq = consumers;
            consumers = null;
            awaitingFetch = false;
        }
        errorAllConsumers(cq, false);
    }

    private void setDecoder(ImageDecoder mydecoder) {
        ImageConsumerQueue cq;
        synchronized (this) {
            mydecoder.next = decoders;
            decoders = mydecoder;
            decoder = mydecoder;
            cq = consumers;
            mydecoder.queue = cq;
            consumers = null;
            awaitingFetch = false;
        }
        while (cq != null) {
            if (cq.interested) {
                // Now that there is a decoder, security may have changed
                // so reverify it here, just in case.
                if (!checkSecurity(cq.securityContext, true)) {
                    errorConsumer(cq, false);
                }
            }
            cq = cq.next;
        }
    }

    private synchronized void removeDecoder(ImageDecoder mydecoder) {
        doneDecoding(mydecoder);
        ImageDecoder idprev = null;
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id == mydecoder) {
                if (idprev == null) {
                    decoders = id.next;
                } else {
                    idprev.next = id.next;
                }
                break;
            }
            idprev = id;
        }
    }

    synchronized void doneDecoding(ImageDecoder mydecoder) {
        if (decoder == mydecoder) {
            decoder = null;
            if (consumers != null) {
                startProduction();
            }
        }
    }

    void latchConsumers(ImageDecoder id) {
        doneDecoding(id);
    }

    synchronized void flush() {
        decoder = null;
    }
}


/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 */
package sun.awt.image;

import java.awt.image.*;
import java.io.InputStream;
import java.io.IOException;
import java.io.BufferedInputStream;
import java.util.Hashtable;

public abstract class InputStreamImageSource implements ImageProducer, ImageFetchable {

    ImageConsumerQueue consumers;

    ImageDecoder decoder;

    ImageDecoder decoders;

    boolean awaitingFetch = false;

    abstract boolean checkSecurity(Object context, boolean quiet);

    int countConsumers(ImageConsumerQueue cq) {
        int i = 0;
        while (cq != null) {
            i++;
            cq = cq.next;
        }
        return i;
    }

    synchronized int countConsumers() {
        ImageDecoder id = decoders;
        int i = countConsumers(consumers);
        while (id != null) {
            i += countConsumers(id.queue);
            id = id.next;
        }
        return i;
    }

    public void addConsumer(ImageConsumer ic) {
        addConsumer(ic, false);
    }

    synchronized void printQueue(ImageConsumerQueue cq, String prefix) {
        while (cq != null) {
            System.out.println(prefix + cq);
            cq = cq.next;
        }
    }

    synchronized void printQueues(String title) {
        System.out.println(title + "[ -----------");
        printQueue(consumers, "  ");
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            System.out.println("    " + id);
            printQueue(id.queue, "      ");
        }
        System.out.println("----------- ]" + title);
    }

    synchronized void addConsumer(ImageConsumer ic, boolean produce) {
        checkSecurity(null, false);
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                // This consumer is already being fed.
                return;
            }
        }
        ImageConsumerQueue cq = consumers;
        while (cq != null && cq.consumer != ic) {
            cq = cq.next;
        }
        if (cq == null) {
            cq = new ImageConsumerQueue(this, ic);
            cq.next = consumers;
            consumers = cq;
        } else {
            if (!cq.secure) {
                Object context = null;
                SecurityManager security = System.getSecurityManager();
                if (security != null) {
                    context = security.getSecurityContext();
                }
                if (cq.securityContext == null) {
                    cq.securityContext = context;
                } else if (!cq.securityContext.equals(context)) {
                    // If there are two different security contexts that both
                    // have a handle on the same ImageConsumer, then there has
                    // been a security breach and whether or not they trade
                    // image data is small fish compared to what they could be
                    // trading.  Throw a Security exception anyway...
                    errorConsumer(cq, false);
                    throw new SecurityException("Applets are trading image data!");
                }
            }
            cq.interested = true;
        }
        if (produce && decoder == null) {
            startProduction();
        }
    }

    public synchronized boolean isConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                return true;
            }
        }
        return ImageConsumerQueue.isConsumer(consumers, ic);
    }

    private void errorAllConsumers(ImageConsumerQueue cq, boolean needReload) {
        while (cq != null) {
            if (cq.interested) {
                errorConsumer(cq, needReload);
            }
            cq = cq.next;
        }
    }

    private void errorConsumer(ImageConsumerQueue cq, boolean needReload) {
        cq.consumer.imageComplete(ImageConsumer.IMAGEERROR);
        if (needReload && cq.consumer instanceof ImageRepresentation) {
            ((ImageRepresentation) cq.consumer).image.flush();
        }
        removeConsumer(cq.consumer);
    }

    public synchronized void removeConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            id.removeConsumer(ic);
        }
        consumers = ImageConsumerQueue.removeConsumer(consumers, ic, false);
    }

    public void startProduction(ImageConsumer ic) {
        addConsumer(ic, true);
    }

    private synchronized void startProduction() {
        if (!awaitingFetch) {
            ImageFetcher.add(this);
            awaitingFetch = true;
        }
    }

    private synchronized void stopProduction() {
        if (awaitingFetch) {
            ImageFetcher.remove(this);
            awaitingFetch = false;
        }
    }

    public void requestTopDownLeftRightResend(ImageConsumer ic) {
    }

    protected abstract ImageDecoder getDecoder();

    protected ImageDecoder decoderForType(InputStream is, String content_type) {
        // Don't believe the content type - file extensions can
        return null;
    }

    protected ImageDecoder getDecoder(InputStream is) {
        if (!is.markSupported())
            is = new BufferedInputStream(is);
        try {
            /* changed to support png
             is.mark(6);
             */
            is.mark(8);
            int c1 = is.read();
            int c2 = is.read();
            int c3 = is.read();
            int c4 = is.read();
            int c5 = is.read();
            int c6 = is.read();
            // added to support png
            int c7 = is.read();
            int c8 = is.read();
            // end of adding
            is.reset();
            is.mark(-1);
            if (c1 == 'G' && c2 == 'I' && c3 == 'F' && c4 == '8') {
                return new GifImageDecoder(this, is);
            } else if (c1 == '\377' && c2 == '\330' && c3 == '\377') {
                return new JPEGImageDecoder(this, is);
            } else if (c1 == '#' && c2 == 'd' && c3 == 'e' && c4 == 'f') {
                return new XbmImageDecoder(this, is);
                // added to support png
            } else

            // end of adding
        } catch (IOException e) {
        }
        return null;
    }

    public void doFetch() {
        synchronized (this) {
            if (consumers == null) {
                awaitingFetch = false;
                return;
            }
        }
        ImageDecoder imgd = getDecoder();
        if (imgd == null) {
            badDecoder();
        } else {
            setDecoder(imgd);
            try {
                imgd.produceImage();
            } catch (IOException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } catch (ImageFormatException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } finally {
                removeDecoder(imgd);
                if (Thread.currentThread().isInterrupted() || !Thread.currentThread().isAlive()) {
                    errorAllConsumers(imgd.queue, true);
                } else {
                    errorAllConsumers(imgd.queue, false);
                }
            }
        }
    }

    private void badDecoder() {
        ImageConsumerQueue cq;
        synchronized (this) {
            cq = consumers;
            consumers = null;
            awaitingFetch = false;
        }
        errorAllConsumers(cq, false);
    }

    private void setDecoder(ImageDecoder mydecoder) {
        ImageConsumerQueue cq;
        synchronized (this) {
            mydecoder.next = decoders;
            decoders = mydecoder;
            decoder = mydecoder;
            cq = consumers;
            mydecoder.queue = cq;
            consumers = null;
            awaitingFetch = false;
        }
        while (cq != null) {
            if (cq.interested) {
                // Now that there is a decoder, security may have changed
                // so reverify it here, just in case.
                if (!checkSecurity(cq.securityContext, true)) {
                    errorConsumer(cq, false);
                }
            }
            cq = cq.next;
        }
    }

    private synchronized void removeDecoder(ImageDecoder mydecoder) {
        doneDecoding(mydecoder);
        ImageDecoder idprev = null;
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id == mydecoder) {
                if (idprev == null) {
                    decoders = id.next;
                } else {
                    idprev.next = id.next;
                }
                break;
            }
            idprev = id;
        }
    }

    synchronized void doneDecoding(ImageDecoder mydecoder) {
        if (decoder == mydecoder) {
            decoder = null;
            if (consumers != null) {
                startProduction();
            }
        }
    }

    void latchConsumers(ImageDecoder id) {
        doneDecoding(id);
    }

    synchronized void flush() {
        decoder = null;
    }
}


for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                return true;
            }
        }

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 */
package sun.awt.image;

import java.awt.image.*;
import java.io.InputStream;
import java.io.IOException;
import java.io.BufferedInputStream;
import java.util.Hashtable;

public abstract class InputStreamImageSource implements ImageProducer, ImageFetchable {

    ImageConsumerQueue consumers;

    ImageDecoder decoder;

    ImageDecoder decoders;

    boolean awaitingFetch = false;

    abstract boolean checkSecurity(Object context, boolean quiet);

    int countConsumers(ImageConsumerQueue cq) {
        int i = 0;
        while (cq != null) {
            i++;
            cq = cq.next;
        }
        return i;
    }

    synchronized int countConsumers() {
        ImageDecoder id = decoders;
        int i = countConsumers(consumers);
        while (id != null) {
            i += countConsumers(id.queue);
            id = id.next;
        }
        return i;
    }

    public void addConsumer(ImageConsumer ic) {
        addConsumer(ic, false);
    }

    synchronized void printQueue(ImageConsumerQueue cq, String prefix) {
        while (cq != null) {
            System.out.println(prefix + cq);
            cq = cq.next;
        }
    }

    synchronized void printQueues(String title) {
        System.out.println(title + "[ -----------");
        printQueue(consumers, "  ");
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            System.out.println("    " + id);
            printQueue(id.queue, "      ");
        }
        System.out.println("----------- ]" + title);
    }

    synchronized void addConsumer(ImageConsumer ic, boolean produce) {
        checkSecurity(null, false);
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                // This consumer is already being fed.
                return;
            }
        }
        ImageConsumerQueue cq = consumers;
        while (cq != null && cq.consumer != ic) {
            cq = cq.next;
        }
        if (cq == null) {
            cq = new ImageConsumerQueue(this, ic);
            cq.next = consumers;
            consumers = cq;
        } else {
            if (!cq.secure) {
                Object context = null;
                SecurityManager security = System.getSecurityManager();
                if (security != null) {
                    context = security.getSecurityContext();
                }
                if (cq.securityContext == null) {
                    cq.securityContext = context;
                } else if (!cq.securityContext.equals(context)) {
                    // If there are two different security contexts that both
                    // have a handle on the same ImageConsumer, then there has
                    // been a security breach and whether or not they trade
                    // image data is small fish compared to what they could be
                    // trading.  Throw a Security exception anyway...
                    errorConsumer(cq, false);
                    throw new SecurityException("Applets are trading image data!");
                }
            }
            cq.interested = true;
        }
        if (produce && decoder == null) {
            startProduction();
        }
    }

    public synchronized boolean isConsumer(ImageConsumer ic) {

        return ImageConsumerQueue.isConsumer(consumers, ic);
    }

    private void errorAllConsumers(ImageConsumerQueue cq, boolean needReload) {
        while (cq != null) {
            if (cq.interested) {
                errorConsumer(cq, needReload);
            }
            cq = cq.next;
        }
    }

    private void errorConsumer(ImageConsumerQueue cq, boolean needReload) {
        cq.consumer.imageComplete(ImageConsumer.IMAGEERROR);
        if (needReload && cq.consumer instanceof ImageRepresentation) {
            ((ImageRepresentation) cq.consumer).image.flush();
        }
        removeConsumer(cq.consumer);
    }

    public synchronized void removeConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            id.removeConsumer(ic);
        }
        consumers = ImageConsumerQueue.removeConsumer(consumers, ic, false);
    }

    public void startProduction(ImageConsumer ic) {
        addConsumer(ic, true);
    }

    private synchronized void startProduction() {
        if (!awaitingFetch) {
            ImageFetcher.add(this);
            awaitingFetch = true;
        }
    }

    private synchronized void stopProduction() {
        if (awaitingFetch) {
            ImageFetcher.remove(this);
            awaitingFetch = false;
        }
    }

    public void requestTopDownLeftRightResend(ImageConsumer ic) {
    }

    protected abstract ImageDecoder getDecoder();

    protected ImageDecoder decoderForType(InputStream is, String content_type) {
        // Don't believe the content type - file extensions can
        return null;
    }

    protected ImageDecoder getDecoder(InputStream is) {
        if (!is.markSupported())
            is = new BufferedInputStream(is);
        try {
            /* changed to support png
             is.mark(6);
             */
            is.mark(8);
            int c1 = is.read();
            int c2 = is.read();
            int c3 = is.read();
            int c4 = is.read();
            int c5 = is.read();
            int c6 = is.read();
            // added to support png
            int c7 = is.read();
            int c8 = is.read();
            // end of adding
            is.reset();
            is.mark(-1);
            if (c1 == 'G' && c2 == 'I' && c3 == 'F' && c4 == '8') {
                return new GifImageDecoder(this, is);
            } else if (c1 == '\377' && c2 == '\330' && c3 == '\377') {
                return new JPEGImageDecoder(this, is);
            } else if (c1 == '#' && c2 == 'd' && c3 == 'e' && c4 == 'f') {
                return new XbmImageDecoder(this, is);
                // added to support png
            } else if (c1 == 137 && c2 == 80 && c3 == 78 && c4 == 71 && c5 == 13 && c6 == 10 && c7 == 26 && c8 == 10) {
                return new PNGImageDecoder(this, is);
            }
            // end of adding
        } catch (IOException e) {
        }
        return null;
    }

    public void doFetch() {
        synchronized (this) {
            if (consumers == null) {
                awaitingFetch = false;
                return;
            }
        }
        ImageDecoder imgd = getDecoder();
        if (imgd == null) {
            badDecoder();
        } else {
            setDecoder(imgd);
            try {
                imgd.produceImage();
            } catch (IOException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } catch (ImageFormatException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } finally {
                removeDecoder(imgd);
                if (Thread.currentThread().isInterrupted() || !Thread.currentThread().isAlive()) {
                    errorAllConsumers(imgd.queue, true);
                } else {
                    errorAllConsumers(imgd.queue, false);
                }
            }
        }
    }

    private void badDecoder() {
        ImageConsumerQueue cq;
        synchronized (this) {
            cq = consumers;
            consumers = null;
            awaitingFetch = false;
        }
        errorAllConsumers(cq, false);
    }

    private void setDecoder(ImageDecoder mydecoder) {
        ImageConsumerQueue cq;
        synchronized (this) {
            mydecoder.next = decoders;
            decoders = mydecoder;
            decoder = mydecoder;
            cq = consumers;
            mydecoder.queue = cq;
            consumers = null;
            awaitingFetch = false;
        }
        while (cq != null) {
            if (cq.interested) {
                // Now that there is a decoder, security may have changed
                // so reverify it here, just in case.
                if (!checkSecurity(cq.securityContext, true)) {
                    errorConsumer(cq, false);
                }
            }
            cq = cq.next;
        }
    }

    private synchronized void removeDecoder(ImageDecoder mydecoder) {
        doneDecoding(mydecoder);
        ImageDecoder idprev = null;
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id == mydecoder) {
                if (idprev == null) {
                    decoders = id.next;
                } else {
                    idprev.next = id.next;
                }
                break;
            }
            idprev = id;
        }
    }

    synchronized void doneDecoding(ImageDecoder mydecoder) {
        if (decoder == mydecoder) {
            decoder = null;
            if (consumers != null) {
                startProduction();
            }
        }
    }

    void latchConsumers(ImageDecoder id) {
        doneDecoding(id);
    }

    synchronized void flush() {
        decoder = null;
    }
}


while (cq != null && cq.consumer != ic) {
            cq = cq.next;
        }

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 */
package sun.awt.image;

import java.awt.image.*;
import java.io.InputStream;
import java.io.IOException;
import java.io.BufferedInputStream;
import java.util.Hashtable;

public abstract class InputStreamImageSource implements ImageProducer, ImageFetchable {

    ImageConsumerQueue consumers;

    ImageDecoder decoder;

    ImageDecoder decoders;

    boolean awaitingFetch = false;

    abstract boolean checkSecurity(Object context, boolean quiet);

    int countConsumers(ImageConsumerQueue cq) {
        int i = 0;
        while (cq != null) {
            i++;
            cq = cq.next;
        }
        return i;
    }

    synchronized int countConsumers() {
        ImageDecoder id = decoders;
        int i = countConsumers(consumers);
        while (id != null) {
            i += countConsumers(id.queue);
            id = id.next;
        }
        return i;
    }

    public void addConsumer(ImageConsumer ic) {
        addConsumer(ic, false);
    }

    synchronized void printQueue(ImageConsumerQueue cq, String prefix) {
        while (cq != null) {
            System.out.println(prefix + cq);
            cq = cq.next;
        }
    }

    synchronized void printQueues(String title) {
        System.out.println(title + "[ -----------");
        printQueue(consumers, "  ");
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            System.out.println("    " + id);
            printQueue(id.queue, "      ");
        }
        System.out.println("----------- ]" + title);
    }

    synchronized void addConsumer(ImageConsumer ic, boolean produce) {
        checkSecurity(null, false);
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                // This consumer is already being fed.
                return;
            }
        }
        ImageConsumerQueue cq = consumers;

        if (cq == null) {
            cq = new ImageConsumerQueue(this, ic);
            cq.next = consumers;
            consumers = cq;
        } else {
            if (!cq.secure) {
                Object context = null;
                SecurityManager security = System.getSecurityManager();
                if (security != null) {
                    context = security.getSecurityContext();
                }
                if (cq.securityContext == null) {
                    cq.securityContext = context;
                } else if (!cq.securityContext.equals(context)) {
                    // If there are two different security contexts that both
                    // have a handle on the same ImageConsumer, then there has
                    // been a security breach and whether or not they trade
                    // image data is small fish compared to what they could be
                    // trading.  Throw a Security exception anyway...
                    errorConsumer(cq, false);
                    throw new SecurityException("Applets are trading image data!");
                }
            }
            cq.interested = true;
        }
        if (produce && decoder == null) {
            startProduction();
        }
    }

    public synchronized boolean isConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                return true;
            }
        }
        return ImageConsumerQueue.isConsumer(consumers, ic);
    }

    private void errorAllConsumers(ImageConsumerQueue cq, boolean needReload) {
        while (cq != null) {
            if (cq.interested) {
                errorConsumer(cq, needReload);
            }
            cq = cq.next;
        }
    }

    private void errorConsumer(ImageConsumerQueue cq, boolean needReload) {
        cq.consumer.imageComplete(ImageConsumer.IMAGEERROR);
        if (needReload && cq.consumer instanceof ImageRepresentation) {
            ((ImageRepresentation) cq.consumer).image.flush();
        }
        removeConsumer(cq.consumer);
    }

    public synchronized void removeConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            id.removeConsumer(ic);
        }
        consumers = ImageConsumerQueue.removeConsumer(consumers, ic, false);
    }

    public void startProduction(ImageConsumer ic) {
        addConsumer(ic, true);
    }

    private synchronized void startProduction() {
        if (!awaitingFetch) {
            ImageFetcher.add(this);
            awaitingFetch = true;
        }
    }

    private synchronized void stopProduction() {
        if (awaitingFetch) {
            ImageFetcher.remove(this);
            awaitingFetch = false;
        }
    }

    public void requestTopDownLeftRightResend(ImageConsumer ic) {
    }

    protected abstract ImageDecoder getDecoder();

    protected ImageDecoder decoderForType(InputStream is, String content_type) {
        // Don't believe the content type - file extensions can
        return null;
    }

    protected ImageDecoder getDecoder(InputStream is) {
        if (!is.markSupported())
            is = new BufferedInputStream(is);
        try {
            /* changed to support png
             is.mark(6);
             */
            is.mark(8);
            int c1 = is.read();
            int c2 = is.read();
            int c3 = is.read();
            int c4 = is.read();
            int c5 = is.read();
            int c6 = is.read();
            // added to support png
            int c7 = is.read();
            int c8 = is.read();
            // end of adding
            is.reset();
            is.mark(-1);
            if (c1 == 'G' && c2 == 'I' && c3 == 'F' && c4 == '8') {
                return new GifImageDecoder(this, is);
            } else if (c1 == '\377' && c2 == '\330' && c3 == '\377') {
                return new JPEGImageDecoder(this, is);
            } else if (c1 == '#' && c2 == 'd' && c3 == 'e' && c4 == 'f') {
                return new XbmImageDecoder(this, is);
                // added to support png
            } else if (c1 == 137 && c2 == 80 && c3 == 78 && c4 == 71 && c5 == 13 && c6 == 10 && c7 == 26 && c8 == 10) {
                return new PNGImageDecoder(this, is);
            }
            // end of adding
        } catch (IOException e) {
        }
        return null;
    }

    public void doFetch() {
        synchronized (this) {
            if (consumers == null) {
                awaitingFetch = false;
                return;
            }
        }
        ImageDecoder imgd = getDecoder();
        if (imgd == null) {
            badDecoder();
        } else {
            setDecoder(imgd);
            try {
                imgd.produceImage();
            } catch (IOException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } catch (ImageFormatException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } finally {
                removeDecoder(imgd);
                if (Thread.currentThread().isInterrupted() || !Thread.currentThread().isAlive()) {
                    errorAllConsumers(imgd.queue, true);
                } else {
                    errorAllConsumers(imgd.queue, false);
                }
            }
        }
    }

    private void badDecoder() {
        ImageConsumerQueue cq;
        synchronized (this) {
            cq = consumers;
            consumers = null;
            awaitingFetch = false;
        }
        errorAllConsumers(cq, false);
    }

    private void setDecoder(ImageDecoder mydecoder) {
        ImageConsumerQueue cq;
        synchronized (this) {
            mydecoder.next = decoders;
            decoders = mydecoder;
            decoder = mydecoder;
            cq = consumers;
            mydecoder.queue = cq;
            consumers = null;
            awaitingFetch = false;
        }
        while (cq != null) {
            if (cq.interested) {
                // Now that there is a decoder, security may have changed
                // so reverify it here, just in case.
                if (!checkSecurity(cq.securityContext, true)) {
                    errorConsumer(cq, false);
                }
            }
            cq = cq.next;
        }
    }

    private synchronized void removeDecoder(ImageDecoder mydecoder) {
        doneDecoding(mydecoder);
        ImageDecoder idprev = null;
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id == mydecoder) {
                if (idprev == null) {
                    decoders = id.next;
                } else {
                    idprev.next = id.next;
                }
                break;
            }
            idprev = id;
        }
    }

    synchronized void doneDecoding(ImageDecoder mydecoder) {
        if (decoder == mydecoder) {
            decoder = null;
            if (consumers != null) {
                startProduction();
            }
        }
    }

    void latchConsumers(ImageDecoder id) {
        doneDecoding(id);
    }

    synchronized void flush() {
        decoder = null;
    }
}


/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 */
package sun.awt.image;

import java.awt.image.*;
import java.io.InputStream;
import java.io.IOException;
import java.io.BufferedInputStream;
import java.util.Hashtable;

public abstract class InputStreamImageSource implements ImageProducer, ImageFetchable {

    ImageConsumerQueue consumers;

    ImageDecoder decoder;

    ImageDecoder decoders;

    boolean awaitingFetch = false;

    abstract boolean checkSecurity(Object context, boolean quiet);

    int countConsumers(ImageConsumerQueue cq) {
        int i = 0;
        while (cq != null) {
            i++;
            cq = cq.next;
        }
        return i;
    }

    synchronized int countConsumers() {
        ImageDecoder id = decoders;
        int i = countConsumers(consumers);
        while (id != null) {
            i += countConsumers(id.queue);
            id = id.next;
        }
        return i;
    }

    public void addConsumer(ImageConsumer ic) {
        addConsumer(ic, false);
    }

    synchronized void printQueue(ImageConsumerQueue cq, String prefix) {
        while (cq != null) {
            System.out.println(prefix + cq);
            cq = cq.next;
        }
    }

    synchronized void printQueues(String title) {
        System.out.println(title + "[ -----------");
        printQueue(consumers, "  ");
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            System.out.println("    " + id);
            printQueue(id.queue, "      ");
        }
        System.out.prin

tln("----------- ]" + title);
    }

    synchronized void addConsumer(ImageConsumer ic, boolean produce) {
        checkSecurity(null, false);
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                // This consumer is already being fed.
                return;
            }
        }
        ImageConsumerQueue cq = consumers;
        while (cq != null && cq.consumer != ic) {
            cq = cq.next;
        }
        if (cq == null) {
            cq = new ImageConsumerQueue(this, ic);
            cq.next = consumers;
            consumers = cq;
        } else {
            if (!cq.secure) {
                Object context = null;
                SecurityManager security = System.getSecurityManager();
                if (security != null) {
                    context = security.getSecurityContext();
                }
                if (cq.securityContext == null) {
                    cq.securityContext = context;
                } else if (!cq.securityContext.equals(context)) {
                    // If there are two different security contexts that both
                    // have a handle on the same ImageConsumer, then there has
                    // been a security breach and whether or not they trade
                    // image data is small fish compared to what they could be
                    // trading.  Throw a Security exception anyway...
                    errorConsumer(cq, false);
                    throw new SecurityException("Applets are trading image data!");
                }
            }
            cq.interested = true;
        }
        if (produce && decoder == null) {
            startProduction();
        }
    }

    public synchronized boolean isConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id.isConsumer(ic)) {
                return true;
            }
        }
        return ImageConsumerQueue.isConsumer(consumers, ic);
    }

    private void errorAllConsumers(ImageConsumerQueue cq, boolean needReload) {
        while (cq != null) {
            if (cq.interested) {
                errorConsumer(cq, needReload);
            }
            cq = cq.next;
        }
    }

    private void errorConsumer(ImageConsumerQueue cq, boolean needReload) {
        cq.consumer.imageComplete(ImageConsumer.IMAGEERROR);
        if (needReload && cq.consumer instanceof ImageRepresentation) {
            ((ImageRepresentation) cq.consumer).image.flush();
        }
        removeConsumer(cq.consumer);
    }

    public synchronized void removeConsumer(ImageConsumer ic) {
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            id.removeConsumer(ic);
        }
        consumers = ImageConsumerQueue.removeConsumer(consumers, ic, false);
    }

    public void startProduction(ImageConsumer ic) {
        addConsumer(ic, true);
    }

    private synchronized void startProduction() {
        if (!awaitingFetch) {
            ImageFetcher.add(this);
            awaitingFetch = true;
        }
    }

    private synchronized void stopProduction() {
        if (awaitingFetch) {
            ImageFetcher.remove(this);
            awaitingFetch = false;
        }
    }

    public void requestTopDownLeftRightResend(ImageConsumer ic) {
    }

    protected abstract ImageDecoder getDecoder();

    protected ImageDecoder decoderForType(InputStream is, String content_type) {
        // Don't believe the content type - file extensions can
        return null;
    }

    protected ImageDecoder getDecoder(InputStream is) {
        if (!is.markSupported())
            is = new BufferedInputStream(is);
        try {
            /* changed to support png
             is.mark(6);
             */
            is.mark(8);
            int c1 = is.read();
            int c2 = is.read();
            int c3 = is.read();
            int c4 = is.read();
            int c5 = is.read();
            int c6 = is.read();
            // added to support png
            int c7 = is.read();
            int c8 = is.read();
            // end of adding
            is.reset();
            is.mark(-1);
            if (c1 == 'G' && c2 == 'I' && c3 == 'F' && c4 == '8') {
                return new GifImageDecoder(this, is);
            } else if (c1 == '\377' && c2 == '\330' && c3 == '\377') {
                return new JPEGImageDecoder(this, is);
            } else if (c1 == '#' && c2 == 'd' && c3 == 'e' && c4 == 'f') {
                return new XbmImageDecoder(this, is);
                // added to support png
            } else if (c1 == 137 && c2 == 80 && c3 == 78 && c4 == 71 && c5 == 13 && c6 == 10 && c7 == 26 && c8 == 10) {
                return new PNGImageDecoder(this, is);
            }
            // end of adding
        } catch (IOException e) {
        }
        return null;
    }

    public void doFetch() {
        synchronized (this) {
            if (consumers == null) {
                awaitingFetch = false;
                return;
            }
        }
        ImageDecoder imgd = getDecoder();
        if (imgd == null) {
            badDecoder();
        } else {
            setDecoder(imgd);
            try {
                imgd.produceImage();
            } catch (IOException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } catch (ImageFormatException e) {
                e.printStackTrace();
                // the finally clause will send an error.
            } finally {
                removeDecoder(imgd);
                if (Thread.currentThread().isInterrupted() || !Thread.currentThread().isAlive()) {
                    errorAllConsumers(imgd.queue, true);
                } else {
                    errorAllConsumers(imgd.queue, false);
                }
            }
        }
    }

    private void badDecoder() {
        ImageConsumerQueue cq;
        synchronized (this) {
            cq = consumers;
            consumers = null;
            awaitingFetch = false;
        }
        errorAllConsumers(cq, false);
    }

    private void setDecoder(ImageDecoder mydecoder) {
        ImageConsumerQueue cq;
        synchronized (this) {
            mydecoder.next = decoders;
            decoders = mydecoder;
            decoder = mydecoder;
            cq = consumers;
            mydecoder.queue = cq;
            consumers = null;
            awaitingFetch = false;
        }
        while (cq != null) {
            if (cq.interested) {
                // Now that there is a decoder, security may have changed
                // so reverify it here, just in case.
                if (!checkSecurity(cq.securityContext, true)) {
                    errorConsumer(cq, false);
                }
            }
            cq = cq.next;
        }
    }

    private synchronized void removeDecoder(ImageDecoder mydecoder) {
        doneDecoding(mydecoder);
        ImageDecoder idprev = null;
        for (ImageDecoder id = decoders; id != null; id = id.next) {
            if (id == mydecoder) {
                if (idprev == null) {
                    decoders = id.next;
                } else {
                    idprev.next = id.next;
                }
                break;
            }
            idprev = id;
        }
    }

    synchronized void doneDecoding(ImageDecoder mydecoder) {
        if (decoder == mydecoder) {
            decoder = null;
            if (consumers != null) {
                startProduction();
            }
        }
    }

    void latchConsumers(ImageDecoder id) {
        doneDecoding(id);
    }

    synchronized void flush() {
        decoder = null;
    }
}


public double chiSquare(double[] expected, long[] observed)

package org.apache.commons.math.stat.inference;

import org.apache.commons.math.MathException;
import org.apache.commons.math.exception.NotPositiveException;
import org.apache.commons.math.exception.NotStrictlyPositiveException;
import org.apache.commons.math.exception.NumberIsTooSmallException;
import org.apache.commons.math.exception.OutOfRangeException;
import org.apache.commons.math.exception.DimensionMismatchException;
import org.apache.commons.math.exception.MathIllegalArgumentException;
import org.apache.commons.math.distribution.ChiSquaredDistribution;
import org.apache.commons.math.distribution.ChiSquaredDistributionImpl;
import org.apache.commons.math.exception.util.LocalizedFormats;
import org.apache.commons.math.util.FastMath;

/**
 * Implements Chi-Square test statistics defined in the
 * {@link UnknownDistributionChiSquareTest} interface.
 *
 * @version $Revision$ $Date$
 */
public class ChiSquareTestImpl implements UnknownDistributionChiSquareTest {

    /**
     * Distribution used to compute inference statistics.
     */
    private ChiSquaredDistribution distribution;

    /**
     * Construct a ChiSquareTestImpl
     */
    public ChiSquareTestImpl() {
        this(new ChiSquaredDistributionImpl(1.0));
    }

    /**
     * Create a test instance using the given distribution for computing
     * inference statistics.
     * @param x distribution used to compute inference statistics.
     * @since 1.2
     */
    public ChiSquareTestImpl(ChiSquaredDistribution x) {
        super();
        setDistribution(x);
    }

    /**
     * {@inheritDoc}
     *
Note: This implementation rescales the
     * expected array if necessary to ensure that the sum of the
     * expected and observed counts are equal.

     *
     * @param observed array of observed frequency counts
     * @param expected array of expected frequency counts
     * @return chi-square test statistic
     * @throws DimensionMismatchException if the arrays length is less than 2.
     */

{
        if (expected.length < 2) {
            throw new DimensionMismatchException(expected.length, 2);
        }
        if (expected.length != observed.length) {
            throw new DimensionMismatchException(expected.length, observed.length);
        }
        checkPositive(expected);
        checkNonNegative(observed);
        double sumExpected = 0d;
        double sumObserved = 0d;
        for (int i = 0; i < observed.length; i++) {
            sumExpected += expected[i];
            sumObserved += observed[i];
        }
        double ratio = 1.0d;
        boolean rescale = false;
        if (FastMath.abs(sumExpected - sumObserved) > 10E-6) {
            ratio = sumObserved / sumExpected;
            rescale = true;
        }
        double sumSq = 0.0d;
        for (int i = 0; i < observed.length; i++) {
            if (rescale) {
                final double dev = observed[i] - ratio * expected[i];
                sumSq += dev * dev / (ratio * expected[i]);
            } else {
                final double dev = observed[i] - expected[i];
                sumSq += dev * dev / expected[i];
            }
        }
        return sumSq;
    }

    /**
     * {@inheritDoc}
     *
Note: This implementation rescales the
     * expected array if necessary to ensure that the sum of the
     * expected and observed counts are equal.

     *
     * @param observed array of observed frequency counts
     * @param expected array of expected frequency counts
     * @return p-value
     * @throws MathIllegalArgumentException if preconditions are not met
     * @throws MathException if an error occurs computing the p-value
     */
    public double chiSquareTest(double[] expected, long[] observed) throws MathException {
        distribution = new ChiSquaredDistributionImpl(expected.length - 1.0);
        return 1.0 - distribution.cumulativeProbability(chiSquare(expected, observed));
    }

    /**
     * {@inheritDoc}
     *
Note: This implementation rescales the
     * expected array if necessary to ensure that the sum of the
     * expected and observed counts are equal.

     *
     * @param observed array of observed frequency counts
     * @param expected array of expected frequency counts
     * @param alpha significance level of the test
     * @return true iff null hypothesis can be rejected with confidence
     * 1 - alpha
     * @throws MathIllegalArgumentException if preconditions are not met
     * @throws MathException if an error occurs performing the test
     */
    public boolean chiSquareTest(double[] expected, long[] observed, double alpha) throws MathException {
        if ((alpha <= 0) || (alpha > 0.5)) {
            throw new OutOfRangeException(LocalizedFormats.OUT_OF_BOUND_SIGNIFICANCE_LEVEL, alpha, 0, 0.5);
        }
        return chiSquareTest(expected, observed) < alpha;
    }

    /**
     * @param counts array representation of 2-way table
     * @return chi-square test statistic
     * @throws MathIllegalArgumentException if preconditions are not met.
     */
    public double chiSquare(long[][] counts) {
        checkArray(counts);
        int nRows = counts.length;
        int nCols = counts[0].length;
        // compute row, column and total sums
        double[] rowSum = new double[nRows];
        double[] colSum = new double[nCols];
        double total = 0.0d;
        for (int row = 0; row < nRows; row++) {
            for (int col = 0; col < nCols; col++) {
                rowSum[row] += counts[row][col];
                colSum[col] += counts[row][col];
                total += counts[row][col];
            }
        }
        // compute expected counts and chi-square
        double sumSq = 0.0d;
        double expected = 0.0d;
        for (int row = 0; row < nRows; row++) {
            for (int col = 0; col < nCols; col++) {
                expected = (rowSum[row] * colSum[col]) / total;
                sumSq += ((counts[row][col] - expected) * (counts[row][col] - expected)) / expected;
            }
        }
        return sumSq;
    }

    /**
     * @param counts array representation of 2-way table
     * @return p-value
     * @throws MathIllegalArgumentException if preconditions are not met
     * @throws MathException if an error occurs computing the p-value
     */
    public double chiSquareTest(long[][] counts) throws MathException {
        checkArray(counts);
        double df = ((double) counts.length - 1) * ((double) counts[0].length - 1);
        distribution = new ChiSquaredDistributionImpl(df);
        return 1 - distribution.cumulativeProbability(chiSquare(counts));
    }

    /**
     * @param counts array representation of 2-way table
     * @param alpha significance level of the test
     * @return true iff null hypothesis can be rejected with confidence
     * 1 - alpha
     * @throws MathIllegalArgumentException if preconditions are not met
     * @throws MathException if an error occurs performing the test
     */
    public boolean chiSquareTest(long[][] counts, double alpha) throws MathException {
        if ((alpha <= 0) || (alpha > 0.5)) {
            throw new OutOfRangeException(LocalizedFormats.OUT_OF_BOUND_SIGNIFICANCE_LEVEL, alpha, 0, 0.5);
        }
        return chiSquareTest(counts) < alpha;
    }

    /**
     * @param observed1 array of observed frequency counts of the first data set
     * @param observed2 array of observed frequency counts of the second data set
     * @return chi-square test statistic
     * @throws MathIllegalArgumentException if preconditions are not met
     * @since 1.2
     */
    public double chiSquareDataSetsComparison(long[] observed1, long[] observed2) {
        // Make sure lengths are same
        if (observed1.length < 2) {
            throw new DimensionMismatchException(observed1.length, 2);
        }
        if (observed1.length != observed2.length) {
            throw new DimensionMismatchException(observed1.length, observed2.length);
        }
        // Ensure non-negative counts
        checkNonNegative(observed1);
        checkNonNegative(observed2);
        // Compute and compare count sums
        long countSum1 = 0;
        long countSum2 = 0;
        boolean unequalCounts = false;
        double weight = 0.0;
        for (int i = 0; i < observed1.length; i++) {
            countSum1 += observed1[i];
            countSum2 += observed2[i];
        }
        // Ensure neither sample is uniformly 0
        if (countSum1 == 0) {
            throw new MathIllegalArgumentException(LocalizedFormats.OBSERVED_COUNTS_ALL_ZERO, 1);
        }
        if (countSum2 == 0) {
            throw new MathIllegalArgumentException(LocalizedFormats.OBSERVED_COUNTS_ALL_ZERO, 2);
        }
        // Compare and compute weight only if different
        unequalCounts = countSum1 != countSum2;
        if (unequalCounts) {
            weight = FastMath.sqrt((double) countSum1 / (double) countSum2);
        }
        // Compute ChiSquare statistic
        double sumSq = 0.0d;
        double dev = 0.0d;
        double obs1 = 0.0d;
        double obs2 = 0.0d;
        for (int i = 0; i < observed1.length; i++) {
            if (observed1[i] == 0 && observed2[i] == 0) {
                throw new MathIllegalArgumentException(LocalizedFormats.OBSERVED_COUNTS_BOTTH_ZERO_FOR_ENTRY, i);
            } else {
                obs1 = observed1[i];
                obs2 = observed2[i];
                if (unequalCounts) {
                    // apply weights
                    dev = obs1 / weight - obs2 * weight;
                } else {
                    dev = obs1 - obs2;
                }
                sumSq += (dev * dev) / (obs1 + obs2);
            }
        }
        return sumSq;
    }

    /**
     * @param observed1 array of observed frequency counts of the first data set
     * @param observed2 array of observed frequency counts of the second data set
     * @return p-value
     * @throws MathIllegalArgumentException if preconditions are not met
     * @throws MathException if an error occurs computing the p-value
     * @since 1.2
     */
    public double chiSquareTestDataSetsComparison(long[] observed1, long[] observed2) throws MathException {
        distribution = new ChiSquaredDistributionImpl((double) observed1.length - 1);
        return 1 - distribution.cumulativeProbability(chiSquareDataSetsComparison(observed1, observed2));
    }

    /**
     * @param observed1 array of observed frequency counts of the first data set
     * @param observed2 array of observed frequency counts of the second data set
     * @param alpha significance level of the test
     * @return true iff null hypothesis can be rejected with confidence
     * 1 - alpha
     * @throws MathIllegalArgumentException if preconditions are not met
     * @throws MathException if an error occurs performing the test
     * @since 1.2
     */
    public boolean chiSquareTestDataSetsComparison(long[] observed1, long[] observed2, double alpha) throws MathException {
        if (alpha <= 0 || alpha > 0.5) {
            throw new OutOfRangeException(LocalizedFormats.OUT_OF_BOUND_SIGNIFICANCE_LEVEL, alpha, 0, 0.5);
        }
        return chiSquareTestDataSetsComparison(observed1, observed2) < alpha;
    }

    /**
     * Checks to make sure that the input long[][] array is rectangular,
     * has at least 2 rows and 2 columns, and has all non-negative entries,
     * throwing MathIllegalArgumentException if any of these checks fail.
     *
     * @param in input 2-way table to check
     * @throws MathIllegalArgumentException if the array is not valid
     */
    private void checkArray(long[][] in) {
        if (in.length < 2) {
            throw new NumberIsTooSmallException(in.length, 2, true);
        }
        if (in[0].length < 2) {
            throw new NumberIsTooSmallException(in[0].length, 2, true);
        }
        checkRectangular(in);
        checkNonNegative(in);
    }

    // ---------------------  Private array methods -- should find a utility home for these
    /**
     * Throws MathIllegalArgumentException if the input array is not rectangular.
     *
     * @param in array to be tested
     * @throws NullPointerException if input array is null
     * @throws MathIllegalArgumentException if input array is not rectangular
     */
    private void checkRectangular(long[][] in) {
        for (int i = 1; i < in.length; i++) {
            if (in[i].length != in[0].length) {
                throw new DimensionMismatchException(LocalizedFormats.DIFFERENT_ROWS_LENGTHS, in[i].length, in[0].length);
            }
        }
    }

    /**
     * Check all entries of the input array are strictly postive.
     *
     * @param in Array to be tested.
     * @exception NotStrictlyPositiveException if one entry is not positive.
     */
    private void checkPositive(double[] in) {
        for (int i = 0; i < in.length; i++) {
            if (in[i] <= 0) {
                throw new NotStrictlyPositiveException(in[i]);
            }
        }
    }

    /**
     * Check all entries of the input array are >= 0.
     *
     * @param in Array to be tested.
     * @exception NotPositiveException if one entry is negative.
     */
    private void checkNonNegative(long[] in) {
        for (int i = 0; i < in.length; i++) {
            if (in[i] < 0) {
                throw new NotPositiveException(in[i]);
            }
        }
    }

    /**
     * Check all entries of the input array are >= 0.
     *
     * @param in Array to be tested.
     * @exception NotPositiveException if one entry is negative.
     */
    private void checkNonNegative(long[][] in) {
        for (int i = 0; i < in.length; i++) {
            for (int j = 0; j < in[i].length; j++) {
                if (in[i][j] < 0) {
                    throw new NotPositiveException(in[i][j]);
                }
            }
        }
    }

    /**
     * Modify the distribution used to compute inference statistics.
     *
     * @param value
     *            the new distribution
     * @since 1.2
     */
    public void setDistribution(ChiSquaredDistribution value) {
        distribution = value;
    }
}