itextpdf-master/itext/src/main/java/com/itextpdf/text/pdf/PdfReader.java
/*
 *
 * This file is part of the iText (R) project.
    Copyright (c) 1998-2022 iText Group NV
 * Authors: Bruno Lowagie, Paulo Soares, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
 * ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
 * OF THIRD PARTY RIGHTS
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Affero General Public License for more details.
 * You should have received a copy of the GNU Affero General Public License
 * along with this program; if not, see http://www.gnu.org/licenses or write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA, 02110-1301 USA, or download the license from the following URL:
 * http://itextpdf.com/terms-of-use/
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License,
 * a covered work must retain the producer line in every PDF that is created
 * or manipulated using iText.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the iText software without
 * disclosing the source code of your own applications.
 * These activities include: offering paid services to customers as an ASP,
 * serving PDFs on the fly in a web application, shipping iText with a closed
 * source product.
 *
 * For more information, please contact iText Software Corp. at this
 * address: sales@itextpdf.com
 */
package com.itextpdf.text.pdf;

import com.itextpdf.text.Document;
import com.itextpdf.text.ExceptionConverter;
import com.itextpdf.text.PageSize;
import com.itextpdf.text.Rectangle;
import com.itextpdf.text.error_messages.MessageLocalization;
import com.itextpdf.text.exceptions.BadPasswordException;
import com.itextpdf.text.exceptions.InvalidPdfException;
import com.itextpdf.text.exceptions.UnsupportedPdfException;
import com.itextpdf.text.io.RandomAccessSource;
import com.itextpdf.text.io.RandomAccessSourceFactory;
import com.itextpdf.text.io.WindowRandomAccessSource;
import com.itextpdf.text.log.Counter;
import com.itextpdf.text.log.CounterFactory;
import com.itextpdf.text.log.Level;
import com.itextpdf.text.log.Logger;
import com.itextpdf.text.log.LoggerFactory;
import com.itextpdf.text.pdf.PRTokeniser.TokenType;
import com.itextpdf.text.pdf.interfaces.PdfViewerPreferences;
import com.itextpdf.text.pdf.internal.PdfViewerPreferencesImp;
import com.itextpdf.text.pdf.security.ExternalDecryptionProcess;
import org.bouncycastle.cert.X509CertificateHolder;
import org.bouncycastle.cms.CMSEnvelopedData;
import org.bouncycastle.cms.RecipientInformation;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.security.Key;
import java.security.MessageDigest;
import java.security.PrivateKey;
import java.security.cert.Certificate;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Stack;
import java.util.zip.InflaterInputStream;

/**
 * Reads a PDF document.
 * @author Paulo Soares
 * @author Kazuya Ujihara
 */
public class PdfReader implements PdfViewerPreferences {

	/**
	 * The iText developers are not responsible if you decide to change the
	 * value of this static parameter.
	 * @since 5.0.2
	 */
	public static boolean unethicalreading = false;
	
	public static boolean debugmode = false;
	private static final Logger LOGGER = LoggerFactory.getLogger(PdfReader.class);
	
    static final PdfName pageInhCandidates[] = {
        PdfName.MEDIABOX, PdfName.ROTATE, PdfName.RESOURCES, PdfName.CROPBOX
    };

    static final byte endstream[] = PdfEncodings.convertToBytes("endstream", null);
    static final byte endobj[] = PdfEncodings.convertToBytes("endobj", null);
    protected PRTokeniser tokens;
    // Each xref pair is a position
    // type 0 -> -1, 0
    // type 1 -> offset, 0
    // type 2 -> index, obj num
    protected long xref[];
    protected HashMap<Integer, IntHashtable> objStmMark;
    protected LongHashtable objStmToOffset;
    protected boolean newXrefType;
    protected ArrayList<PdfObject> xrefObj;
    PdfDictionary rootPages;
    protected PdfDictionary trailer;
    protected PdfDictionary catalog;
    protected PageRefs pageRefs;
    protected PRAcroForm acroForm = null;
    protected boolean acroFormParsed = false;
    protected boolean encrypted = false;
    protected boolean rebuilt = false;
    protected int freeXref;
    protected boolean tampered = false;
    protected long lastXref;
    protected long eofPos;
    protected char pdfVersion;
    protected PdfEncryption decrypt;
    protected byte password[] = null; //added by ujihara for decryption
    protected Key certificateKey = null; //added by Aiken Sam for certificate decryption
    protected Certificate certificate = null; //added by Aiken Sam for certificate decryption
    protected String certificateKeyProvider = null; //added by Aiken Sam for certificate decryption
    protected ExternalDecryptionProcess externalDecryptionProcess = null;
    private boolean ownerPasswordUsed;
    protected ArrayList<PdfString> strings = new ArrayList<PdfString>();
    protected boolean sharedStreams = true;
    protected boolean consolidateNamedDestinations = false;
    protected boolean remoteToLocalNamedDestinations = false;
    protected int rValue;
    protected long pValue;
    private int objNum;
    private int objGen;
    private long fileLength;
    private boolean hybridXref;
    private int lastXrefPartial = -1;
    private boolean partial;

    private PRIndirectReference cryptoRef;
	private final PdfViewerPreferencesImp viewerPreferences = new PdfViewerPreferencesImp();
    private boolean encryptionError;

    /**
     * Handler which will be used for decompression of pdf streams.
     */
    MemoryLimitsAwareHandler memoryLimitsAwareHandler = null;

    /**
     * Holds value of property appendable.
     */
    private boolean appendable;

	protected static Counter COUNTER = CounterFactory.getCounter(PdfReader.class);
	protected Counter getCounter() {
		return COUNTER;
	}
	
    /**
     * Constructs a new PdfReader.  This is the master constructor.
     * @param byteSource source of bytes for the reader
     * @param partialRead if true, the reader is opened in partial mode (PDF is parsed on demand), if false, the entire PDF is parsed into memory as the reader opens
     * @param ownerPassword the password or null if no password is required
     * @param certificate the certificate or null if no certificate is required
     * @param certificateKey the key or null if no certificate key is required
     * @param certificateKeyProvider the name of the key provider, or null if no key is required
     * @param externalDecryptionProcess
     * @param closeSourceOnConstructorError if true, the byteSource will be closed if there is an error during construction of this reader
     */
    private PdfReader(RandomAccessSource byteSource, boolean partialRead, byte ownerPassword[], Certificate certificate, Key certificateKey, String certificateKeyProvider, ExternalDecryptionProcess externalDecryptionProcess, boolean closeSourceOnConstructorError) throws IOException {
        this(byteSource, new ReaderProperties().setCertificate(certificate).setCertificateKey(certificateKey).setCertificateKeyProvider(certificateKeyProvider).setExternalDecryptionProcess(externalDecryptionProcess)
        .setOwnerPassword(ownerPassword).setPartialRead(partialRead).setCloseSourceOnconstructorError(closeSourceOnConstructorError));
    }


    /**
     * Constructs a new PdfReader.  This is the master constructor.
     * @param byteSource source of bytes for the reader
     * @param properties the properties which will be used to create the reader
     */
    private PdfReader(RandomAccessSource byteSource, ReaderProperties properties) throws IOException {
        this.certificate = properties.certificate;
        this.certificateKey = properties.certificateKey;
        this.certificateKeyProvider = properties.certificateKeyProvider;
        this.externalDecryptionProcess = properties.externalDecryptionProcess;
        this.password = properties.ownerPassword;
        this.partial = properties.partialRead;
        this.memoryLimitsAwareHandler = properties.memoryLimitsAwareHandler;
        try{

            tokens = getOffsetTokeniser(byteSource);

            if (partial){
                readPdfPartial();
            } else {
                readPdf();
            }
        } catch (IOException e){
            if (properties.closeSourceOnconstructorError)
                byteSource.close();
            throw e;
        }
        getCounter().read(fileLength);
    }

    /**
     * Reads and parses a PDF document.
     * @param filename the file name of the document
     * @throws IOException on error
     */
    public PdfReader(final String filename) throws IOException {
        this(filename, (byte[]) null);
    }

    /**
     * Reads and parses a PDF document.
     * @param properties the properties which will be used to create the reader
     * @param filename the file name of the document
     * @throws IOException on error
     */
    public PdfReader(ReaderProperties properties, final String filename) throws IOException {
        this(new RandomAccessSourceFactory()
                        .setForceRead(false)
                        .setUsePlainRandomAccess(Document.plainRandomAccess)
                        .createBestSource(filename),
                properties);
    }

    /**
     * Reads and parses a PDF document.
     * @param filename the file name of the document
     * @param ownerPassword the password to read the document
     * @throws IOException on error
     */
    public PdfReader(final String filename, final byte ownerPassword[]) throws IOException {
        this(new ReaderProperties().setOwnerPassword(ownerPassword), filename);
    }


    /**
     * Reads and parses a PDF document.
     * @param filename the file name of the document
     * @param ownerPassword the password to read the document
     * @param partial indicates if the reader needs to read the document only partially
     * @throws IOException on error
     */
    public PdfReader(final String filename, final byte ownerPassword[], boolean partial) throws IOException {
        this(new RandomAccessSourceFactory()
                .setForceRead(false)
                .setUsePlainRandomAccess(Document.plainRandomAccess)
                .createBestSource(filename), new ReaderProperties().setOwnerPassword(ownerPassword).setPartialRead(partial));
    }

    /**
     * Reads and parses a PDF document.
     * @param pdfIn the byte array with the document
     * @throws IOException on error
     */
    public PdfReader(final byte pdfIn[]) throws IOException {
        this(new RandomAccessSourceFactory().createSource(pdfIn), new ReaderProperties());
    }

    /**
     * Reads and parses a PDF document.
     * @param pdfIn the byte array with the document
     * @param ownerPassword the password to read the document
     * @throws IOException on error
     */
    public PdfReader(final byte pdfIn[], final byte ownerPassword[]) throws IOException {
        this(new RandomAccessSourceFactory().createSource(pdfIn), new ReaderProperties().setOwnerPassword(ownerPassword));
    }

    /**
     * Reads and parses a PDF document.
     * @param filename the file name of the document
     * @param certificate the certificate to read the document
     * @param certificateKey the private key of the certificate
     * @param certificateKeyProvider the security provider for certificateKey
     * @throws IOException on error
     */
    public PdfReader(final String filename, final Certificate certificate, final Key certificateKey, final String certificateKeyProvider) throws IOException {
        this(new RandomAccessSourceFactory()
    			.setForceRead(false)
    			.setUsePlainRandomAccess(Document.plainRandomAccess)
    			.createBestSource(filename),
    			new ReaderProperties().setCertificate(certificate).setCertificateKey(certificateKey).setCertificateKeyProvider(certificateKeyProvider));
    }


    /**
     * Reads and parses a PDF document.
     * @param filename the file name of the document
     * @param certificate
     * @param externalDecryptionProcess
     * @throws IOException on error
     */
    public PdfReader(final String filename, Certificate certificate, final ExternalDecryptionProcess externalDecryptionProcess) throws IOException {
        this(new RandomAccessSourceFactory()
                        .setForceRead(false)
                        .setUsePlainRandomAccess(Document.plainRandomAccess)
                        .createBestSource(filename),
                new ReaderProperties().setCertificate(certificate).setExternalDecryptionProcess(externalDecryptionProcess));
    }

    /**
     * Reads and parses a PDF document.
     *
     * @param pdfIn the document as a byte array
     * @param certificate
     * @param externalDecryptionProcess
     * @throws IOException on error
     */
    public PdfReader(final byte[] pdfIn, Certificate certificate, final ExternalDecryptionProcess externalDecryptionProcess) throws IOException {
        this(new RandomAccessSourceFactory()
                        .setForceRead(false)
                        .setUsePlainRandomAccess(Document.plainRandomAccess)
                        .createSource(pdfIn),
                new ReaderProperties().setCertificate(certificate).setExternalDecryptionProcess(externalDecryptionProcess));
    }

    /**
     * Reads and parses a PDF document.
     *
     * @param inputStream the PDF file
     * @param certificate
     * @param externalDecryptionProcess
     * @throws IOException on error
     */
    public PdfReader(final InputStream inputStream, final Certificate certificate, final ExternalDecryptionProcess externalDecryptionProcess) throws IOException {
        this(new RandomAccessSourceFactory().setForceRead(false).setUsePlainRandomAccess(Document.plainRandomAccess).createSource(inputStream),
                new ReaderProperties().setCertificate(certificate).setExternalDecryptionProcess(externalDecryptionProcess));
    }

    /**
     * Reads and parses a PDF document.
     * @param url the URL of the document
     * @throws IOException on error
     */
    public PdfReader(final URL url) throws IOException {
        this(new RandomAccessSourceFactory().createSource(url), new ReaderProperties());
    }

    /**
     * Reads and parses a PDF document.
     * @param url the URL of the document
     * @param ownerPassword the password to read the document
     * @throws IOException on error
     */
    public PdfReader(final URL url, final byte ownerPassword[]) throws IOException {
        this(new RandomAccessSourceFactory().createSource(url),
    			new ReaderProperties().setOwnerPassword(ownerPassword));
    }

    /**
     * Reads and parses a PDF document.
     * @param is the <CODE>InputStream</CODE> containing the document. The stream is read to the
     * end but is not closed
     * @param ownerPassword the password to read the document
     * @throws IOException on error
     */
    public PdfReader(final InputStream is, final byte ownerPassword[]) throws IOException {
        this(new RandomAccessSourceFactory().createSource(is),
    			new ReaderProperties().setOwnerPassword(ownerPassword).setCloseSourceOnconstructorError(false));
    	
    }

    /**
     * Reads and parses a PDF document.
     * @param is the <CODE>InputStream</CODE> containing the document. The stream is read to the
     * end but is not closed
     * @throws IOException on error
     */
    public PdfReader(final InputStream is) throws IOException {
        this(new RandomAccessSourceFactory().createSource(is), new ReaderProperties().setCloseSourceOnconstructorError(false));
    }

    /**
     * Reads and parses a PDF document.
     * @param properties the properties which will be used to create the reader
     * @param is the <CODE>InputStream</CODE> containing the document. The stream is read to the
     * end but is not closed
     * @throws IOException on error
     */
    public PdfReader(ReaderProperties properties, final InputStream is) throws IOException {
        this(new RandomAccessSourceFactory().createSource(is), properties);
    }

    /**
     * Reads and parses a PDF document.
     * @param properties the properties which will be used to create the reader
     * @param raf the document location
     * @throws IOException on error
     */
    public PdfReader(ReaderProperties properties, final RandomAccessFileOrArray raf) throws IOException {
        this(raf.getByteSource(), properties);
    }


    /**
     * Reads and parses a pdf document. Contrary to the other constructors only the xref is read
     * into memory. The reader is said to be working in "partial" mode as only parts of the pdf
     * are read as needed.
     * @param raf the document location
     * @param ownerPassword the password or <CODE>null</CODE> for no password
     * @throws IOException on error
     */
    public PdfReader(final RandomAccessFileOrArray raf, final byte ownerPassword[]) throws IOException {
        this(new ReaderProperties().setOwnerPassword(ownerPassword).setPartialRead(true).setCloseSourceOnconstructorError(false), raf);
    }

    /**
     * Reads and parses a pdf document.
     * @param raf the document location
     * @param ownerPassword the password or <CODE>null</CODE> for no password
     * @param partial indicates if the reader needs to read the document only partially. See {@link PdfReader#PdfReader(RandomAccessFileOrArray, byte[])}
     * @throws IOException on error
     */
    public PdfReader(final RandomAccessFileOrArray raf, final byte ownerPassword[], boolean partial) throws IOException {
        this(raf.getByteSource(), new ReaderProperties().setPartialRead(partial).setOwnerPassword(ownerPassword).setCloseSourceOnconstructorError(false));
    }

    /** Creates an independent duplicate.
     * @param reader the <CODE>PdfReader</CODE> to duplicate
     */
    public PdfReader(final PdfReader reader) {
        this.appendable = reader.appendable;
        this.consolidateNamedDestinations = reader.consolidateNamedDestinations;
        this.encrypted = reader.encrypted;
        this.rebuilt = reader.rebuilt;
        this.sharedStreams = reader.sharedStreams;
        this.tampered = reader.tampered;
        this.password = reader.password;
        this.pdfVersion = reader.pdfVersion;
        this.eofPos = reader.eofPos;
        this.freeXref = reader.freeXref;
        this.lastXref = reader.lastXref;
        this.newXrefType = reader.newXrefType;
        this.tokens = new PRTokeniser(reader.tokens.getSafeFile()); 
        if (reader.decrypt != null)
            this.decrypt = new PdfEncryption(reader.decrypt);
        this.pValue = reader.pValue;
        this.rValue = reader.rValue;
        this.xrefObj = new ArrayList<PdfObject>(reader.xrefObj);
        for (int k = 0; k < reader.xrefObj.size(); ++k) {
            this.xrefObj.set(k, duplicatePdfObject(reader.xrefObj.get(k), this));
        }
        this.pageRefs = new PageRefs(reader.pageRefs, this);
        this.trailer = (PdfDictionary)duplicatePdfObject(reader.trailer, this);
        this.catalog = trailer.getAsDict(PdfName.ROOT);
        this.rootPages = catalog.getAsDict(PdfName.PAGES);
        this.fileLength = reader.fileLength;
        this.partial = reader.partial;
        this.hybridXref = reader.hybridXref;
        this.objStmToOffset = reader.objStmToOffset;
        this.xref = reader.xref;
        this.cryptoRef = (PRIndirectReference)duplicatePdfObject(reader.cryptoRef, this);
        this.ownerPasswordUsed = reader.ownerPasswordUsed;
    }

    /**
     * Utility method that checks the provided byte source to see if it has junk bytes at the beginning.  If junk bytes
     * are found, construct a tokeniser that ignores the junk.  Otherwise, construct a tokeniser for the byte source as it is
     * @param byteSource the source to check
     * @return a tokeniser that is guaranteed to start at the PDF header
     * @throws IOException if there is a problem reading the byte source
     */
    private static PRTokeniser getOffsetTokeniser(RandomAccessSource byteSource) throws IOException{
    	PRTokeniser tok = new PRTokeniser(new RandomAccessFileOrArray(byteSource));
    	int offset = tok.getHeaderOffset();
    	if (offset != 0){
    		RandomAccessSource offsetSource = new WindowRandomAccessSource(byteSource, offset);
    		tok = new PRTokeniser(new RandomAccessFileOrArray(offsetSource));
    	}
    	return tok;
    }
    
    /** Gets a new file instance of the original PDF
     * document.
     * @return a new file instance of the original PDF document
     */
    public RandomAccessFileOrArray getSafeFile() {
        return tokens.getSafeFile();
    }

    protected PdfReaderInstance getPdfReaderInstance(final PdfWriter writer) {
        return new PdfReaderInstance(this, writer);
    }

    /** Gets the number of pages in the document.
     * Partial mode: return the value stored in the COUNT field of the pageref
     * Full mode: return the total number of pages found while loading in the entire document.
     * @return the number of pages in the document
     */
    public int getNumberOfPages() {
        return pageRefs.size();
    }

    /**
     * Returns the document's catalog. This dictionary is not a copy,
     * any changes will be reflected in the catalog.
     * @return the document's catalog
     */
    public PdfDictionary getCatalog() {
        return catalog;
    }

    /**
     * Returns the document's acroform, if it has one.
     * @return the document's acroform
     */
    public PRAcroForm getAcroForm() {
        if (!acroFormParsed) {
            acroFormParsed = true;
            PdfObject form = catalog.get(PdfName.ACROFORM);
            if (form != null) {
                try {
                    acroForm = new PRAcroForm(this);
                    acroForm.readAcroForm((PdfDictionary)getPdfObject(form));
                }
                catch (Exception e) {
                    acroForm = null;
                }
            }
        }
        return acroForm;
    }

    MemoryLimitsAwareHandler getMemoryLimitsAwareHandler() {
        return memoryLimitsAwareHandler;
    }

    /**
     * Gets the page rotation. This value can be 0, 90, 180 or 270.
     * @param index the page number. The first page is 1
     * @return the page rotation
     */
    public int getPageRotation(final int index) {
        return getPageRotation(pageRefs.getPageNRelease(index));
    }

    int getPageRotation(final PdfDictionary page) {
        PdfNumber rotate = page.getAsNumber(PdfName.ROTATE);
        if (rotate == null)
            return 0;
        else {
            int n = rotate.intValue();
            n %= 360;
            return n < 0 ? n + 360 : n;
        }
    }
    /** Gets the page size, taking rotation into account. This
     * is a <CODE>Rectangle</CODE> with the value of the /MediaBox and the /Rotate key.
     * @param index the page number. The first page is 1
     * @return a <CODE>Rectangle</CODE>
     */
    public Rectangle getPageSizeWithRotation(final int index) {
        return getPageSizeWithRotation(pageRefs.getPageNRelease(index));
    }

    /**
     * Gets the rotated page from a page dictionary.
     * @param page the page dictionary
     * @return the rotated page
     */
    public Rectangle getPageSizeWithRotation(final PdfDictionary page) {
        Rectangle rect = getPageSize(page);
        int rotation = getPageRotation(page);
        while (rotation > 0) {
            rect = rect.rotate();
            rotation -= 90;
        }
        return rect;
    }

    /** Gets the page size without taking rotation into account. This
     * is the value of the /MediaBox key.
     * @param index the page number. The first page is 1
     * @return the page size
     */
    public Rectangle getPageSize(final int index) {
        return getPageSize(pageRefs.getPageNRelease(index));
    }

    /**
     * Gets the page from a page dictionary
     * @param page the page dictionary
     * @return the page
     */
    public Rectangle getPageSize(final PdfDictionary page) {
        PdfArray mediaBox = page.getAsArray(PdfName.MEDIABOX);
        return getNormalizedRectangle(mediaBox);
    }

    /** Gets the crop box without taking rotation into account. This
     * is the value of the /CropBox key. The crop box is the part
     * of the document to be displayed or printed. It usually is the same
     * as the media box but may be smaller. If the page doesn't have a crop
     * box the page size will be returned.
     * @param index the page number. The first page is 1
     * @return the crop box
     */
    public Rectangle getCropBox(final int index) {
        PdfDictionary page = pageRefs.getPageNRelease(index);
        PdfArray cropBox = (PdfArray)getPdfObjectRelease(page.get(PdfName.CROPBOX));
        if (cropBox == null)
            return getPageSize(page);
        return getNormalizedRectangle(cropBox);
    }

    /** Gets the box size. Allowed names are: "crop", "trim", "art", "bleed" and "media".
     * @param index the page number. The first page is 1
     * @param boxName the box name
     * @return the box rectangle or null
     */
    public Rectangle getBoxSize(final int index, final String boxName) {
        PdfDictionary page = pageRefs.getPageNRelease(index);
        PdfArray box = null;
        if (boxName.equals("trim"))
            box = (PdfArray)getPdfObjectRelease(page.get(PdfName.TRIMBOX));
        else if (boxName.equals("art"))
            box = (PdfArray)getPdfObjectRelease(page.get(PdfName.ARTBOX));
        else if (boxName.equals("bleed"))
            box = (PdfArray)getPdfObjectRelease(page.get(PdfName.BLEEDBOX));
        else if (boxName.equals("crop"))
            box = (PdfArray)getPdfObjectRelease(page.get(PdfName.CROPBOX));
        else if (boxName.equals("media"))
            box = (PdfArray)getPdfObjectRelease(page.get(PdfName.MEDIABOX));
        if (box == null)
            return null;
        return getNormalizedRectangle(box);
    }

    /**
     * Returns the content of the document information dictionary as a <CODE>HashMap</CODE>
     * of <CODE>String</CODE>.
     * @return content of the document information dictionary
     */
    public HashMap<String, String> getInfo() {
        HashMap<String, String> map = new HashMap<String, String>();
        PdfDictionary info = trailer.getAsDict(PdfName.INFO);
        if (info == null)
            return map;
        for (Object element : info.getKeys()) {
            PdfName key = (PdfName)element;
            PdfObject obj = getPdfObject(info.get(key));
            if (obj == null)
                continue;
            String value = obj.toString();
            switch (obj.type()) {
                case PdfObject.STRING: {
                    value = ((PdfString)obj).toUnicodeString();
                    break;
                }
                case PdfObject.NAME: {
                    value = PdfName.decodeName(value);
                    break;
                }
            }
            map.put(PdfName.decodeName(key.toString()), value);
        }
        return map;
    }

    /** Normalizes a <CODE>Rectangle</CODE> so that llx and lly are smaller than urx and ury.
     * @param box the original rectangle
     * @return a normalized <CODE>Rectangle</CODE>
     */
    public static Rectangle getNormalizedRectangle(final PdfArray box) {
        float llx = ((PdfNumber)getPdfObjectRelease(box.getPdfObject(0))).floatValue();
        float lly = ((PdfNumber)getPdfObjectRelease(box.getPdfObject(1))).floatValue();
        float urx = ((PdfNumber)getPdfObjectRelease(box.getPdfObject(2))).floatValue();
        float ury = ((PdfNumber)getPdfObjectRelease(box.getPdfObject(3))).floatValue();
        return new Rectangle(Math.min(llx, urx), Math.min(lly, ury),
        Math.max(llx, urx), Math.max(lly, ury));
    }
    
    /**
     * Checks if the PDF is a tagged PDF.
     */
    public boolean isTagged() {
    	PdfDictionary markInfo = catalog.getAsDict(PdfName.MARKINFO);
    	if (markInfo == null)
    		return false;
    	if ( PdfBoolean.PDFTRUE.equals(markInfo.getAsBoolean(PdfName.MARKED))) {
            return catalog.getAsDict(PdfName.STRUCTTREEROOT) != null;
        } else {
            return false;
        }
    }

    /**
     * Parses the entire PDF
     */
    protected void readPdf() throws IOException {
        fileLength = tokens.getFile().length();
        pdfVersion = tokens.checkPdfHeader();
        if (null == memoryLimitsAwareHandler) {
            memoryLimitsAwareHandler = new MemoryLimitsAwareHandler(fileLength);
        }
        try {
            readXref();
        }
        catch (Exception e) {
            try {
                rebuilt = true;
                rebuildXref();
                lastXref = -1;
            }
            catch (Exception ne) {
                throw new InvalidPdfException(MessageLocalization.getComposedMessage("rebuild.failed.1.original.message.2", ne.getMessage(), e.getMessage()));
            }
        }
        try {
            readDocObj();
        }
        catch (Exception e) {
        	if (e instanceof BadPasswordException)
        		throw new BadPasswordException(e.getMessage());
            if (rebuilt || encryptionError)
                throw new InvalidPdfException(e.getMessage());
            rebuilt = true;
            encrypted = false;
            try{
                rebuildXref();
                lastXref = -1;
                readDocObj();
            } catch (Exception ne){
                throw new InvalidPdfException(MessageLocalization.getComposedMessage("rebuild.failed.1.original.message.2", ne.getMessage(), e.getMessage()));
            }
        }
        strings.clear();
        readPages();
        //eliminateSharedStreams();
        removeUnusedObjects();

    }
    /**
     * Partially parses the pdf
     *
     * */

    protected void readPdfPartial() throws IOException {
        fileLength = tokens.getFile().length();
        pdfVersion = tokens.checkPdfHeader();
        if (null == memoryLimitsAwareHandler) {
            memoryLimitsAwareHandler = new MemoryLimitsAwareHandler(fileLength);
        }
        try {
            readXref();
        }
        catch (Exception e) {
			try {
				rebuilt = true;
				rebuildXref();
				lastXref = -1;
			} catch (Exception ne) {
				throw new InvalidPdfException(
						MessageLocalization.getComposedMessage(
								"rebuild.failed.1.original.message.2",
								ne.getMessage(), e.getMessage()), ne);
			}
		}
		readDocObjPartial();
		readPages();
    }

    private boolean equalsArray(final byte ar1[], final byte ar2[], final int size) {
        for (int k = 0; k < size; ++k) {
            if (ar1[k] != ar2[k])
                return false;
        }
        return true;
    }

    /**
     * @throws IOException
     */
    @SuppressWarnings("unchecked")
    private void readDecryptedDocObj() throws IOException {
        if (encrypted)
            return;
        PdfObject encDic = trailer.get(PdfName.ENCRYPT);
        if (encDic == null || encDic.toString().equals("null"))
            return;
        encryptionError = true;
        byte[] encryptionKey = null;
        encrypted = true;
        PdfDictionary enc = (PdfDictionary)getPdfObject(encDic);
        //This string of condidions is to determine whether or not the authevent for this PDF is EFOPEN
        //If it is, we return since the attachments of the PDF are what are encrypted, not the PDF itself.  
        //Without this check we run into a bad password exception when trying to open documents that have an
        //auth event type of EFOPEN.  
        PdfDictionary cfDict = enc.getAsDict(PdfName.CF);
        if(cfDict != null){
        	PdfDictionary stdCFDict = cfDict.getAsDict(PdfName.STDCF);
        	if(stdCFDict != null){
        		PdfName authEvent = stdCFDict.getAsName(PdfName.AUTHEVENT);
        		if(authEvent != null){
        			//Return only if the event is EFOPEN and there is no password so that 
        			//attachments that are encrypted can still be opened.
        			if(authEvent.compareTo(PdfName.EFOPEN) == 0 && !this.ownerPasswordUsed)
        				return;
        		}
        	}
        }
        String s;
        PdfObject o;

        PdfArray documentIDs = trailer.getAsArray(PdfName.ID);
        byte documentID[] = null;
        if (documentIDs != null) {
            o = documentIDs.getPdfObject(0);
            strings.remove(o);
            s = o.toString();
            documentID = com.itextpdf.text.DocWriter.getISOBytes(s);
            if (documentIDs.size() > 1)
                strings.remove(documentIDs.getPdfObject(1));
        }
        // just in case we have a broken producer
        if (documentID == null)
            documentID = new byte[0];
        byte uValue[] = null;
        byte oValue[] = null;
        int cryptoMode = PdfWriter.STANDARD_ENCRYPTION_40;
        int lengthValue = 0;

        PdfObject filter = getPdfObjectRelease(enc.get(PdfName.FILTER));

        if (filter.equals(PdfName.STANDARD)) {
            s = enc.get(PdfName.U).toString();
            strings.remove(enc.get(PdfName.U));
            uValue = com.itextpdf.text.DocWriter.getISOBytes(s);
            s = enc.get(PdfName.O).toString();
            strings.remove(enc.get(PdfName.O));
            oValue = com.itextpdf.text.DocWriter.getISOBytes(s);
            if (enc.contains(PdfName.OE))
                strings.remove(enc.get(PdfName.OE));
            if (enc.contains(PdfName.UE))
                strings.remove(enc.get(PdfName.UE));
            if (enc.contains(PdfName.PERMS))
                strings.remove(enc.get(PdfName.PERMS));

            o = enc.get(PdfName.P);
            if (!o.isNumber())
            	throw new InvalidPdfException(MessageLocalization.getComposedMessage("illegal.p.value"));
            pValue = ((PdfNumber)o).longValue();

            o = enc.get(PdfName.R);
            if (!o.isNumber())
            	throw new InvalidPdfException(MessageLocalization.getComposedMessage("illegal.r.value"));
            rValue = ((PdfNumber)o).intValue();

            switch (rValue) {
            case 2:
            	cryptoMode = PdfWriter.STANDARD_ENCRYPTION_40;
            	break;
            case 3:
                o = enc.get(PdfName.LENGTH);
                if (!o.isNumber())
                    throw new InvalidPdfException(MessageLocalization.getComposedMessage("illegal.length.value"));
                lengthValue = ( (PdfNumber) o).intValue();
                if (lengthValue > 128 || lengthValue < 40 || lengthValue % 8 != 0)
                    throw new InvalidPdfException(MessageLocalization.getComposedMessage("illegal.length.value"));
                cryptoMode = PdfWriter.STANDARD_ENCRYPTION_128;
                break;
            case 4:
                PdfDictionary dic = (PdfDictionary)enc.get(PdfName.CF);
                if (dic == null)
                    throw new InvalidPdfException(MessageLocalization.getComposedMessage("cf.not.found.encryption"));
                dic = (PdfDictionary)dic.get(PdfName.STDCF);
                if (dic == null)
                    throw new InvalidPdfException(MessageLocalization.getComposedMessage("stdcf.not.found.encryption"));
                if (PdfName.V2.equals(dic.get(PdfName.CFM)))
                    cryptoMode = PdfWriter.STANDARD_ENCRYPTION_128;
                else if (PdfName.AESV2.equals(dic.get(PdfName.CFM)))
                    cryptoMode = PdfWriter.ENCRYPTION_AES_128;
                else
                    throw new UnsupportedPdfException(MessageLocalization.getComposedMessage("no.compatible.encryption.found"));
                PdfObject em = enc.get(PdfName.ENCRYPTMETADATA);
                if (em != null && em.toString().equals("false"))
                    cryptoMode |= PdfWriter.DO_NOT_ENCRYPT_METADATA;
                break;
            case 5:
                cryptoMode = PdfWriter.ENCRYPTION_AES_256;
                PdfObject em5 = enc.get(PdfName.ENCRYPTMETADATA);
                if (em5 != null && em5.toString().equals("false"))
                    cryptoMode |= PdfWriter.DO_NOT_ENCRYPT_METADATA;
                break;
            default:
            	throw new UnsupportedPdfException(MessageLocalization.getComposedMessage("unknown.encryption.type.r.eq.1", rValue));
            }
        }
        else if (filter.equals(PdfName.PUBSEC)) {
            boolean foundRecipient = false;
            byte[] envelopedData = null;
            PdfArray recipients = null;

            o = enc.get(PdfName.V);
            if (!o.isNumber())
            	throw new InvalidPdfException(MessageLocalization.getComposedMessage("illegal.v.value"));
            int vValue = ((PdfNumber)o).intValue();
            switch(vValue) {
            case 1:
                cryptoMode = PdfWriter.STANDARD_ENCRYPTION_40;
                lengthValue = 40;
                recipients = (PdfArray)enc.get(PdfName.RECIPIENTS);
            	break;
            case 2:
                o = enc.get(PdfName.LENGTH);
                if (!o.isNumber())
                    throw new InvalidPdfException(MessageLocalization.getComposedMessage("illegal.length.value"));
                lengthValue = ( (PdfNumber) o).intValue();
                if (lengthValue > 128 || lengthValue < 40 || lengthValue % 8 != 0)
                    throw new InvalidPdfException(MessageLocalization.getComposedMessage("illegal.length.value"));
                cryptoMode = PdfWriter.STANDARD_ENCRYPTION_128;
                recipients = (PdfArray)enc.get(PdfName.RECIPIENTS);
                break;
            case 4:
            case 5:
                PdfDictionary dic = (PdfDictionary)enc.get(PdfName.CF);
                if (dic == null)
                    throw new InvalidPdfException(MessageLocalization.getComposedMessage("cf.not.found.encryption"));
                dic = (PdfDictionary)dic.get(PdfName.DEFAULTCRYPTFILTER);
                if (dic == null)
                    throw new InvalidPdfException(MessageLocalization.getComposedMessage("defaultcryptfilter.not.found.encryption"));
                if (PdfName.V2.equals(dic.get(PdfName.CFM))) {
                    cryptoMode = PdfWriter.STANDARD_ENCRYPTION_128;
                    lengthValue = 128;
                }
                else if (PdfName.AESV2.equals(dic.get(PdfName.CFM))) {
                    cryptoMode = PdfWriter.ENCRYPTION_AES_128;
                    lengthValue = 128;
                }
                else if (PdfName.AESV3.equals(dic.get(PdfName.CFM))) {
                    cryptoMode = PdfWriter.ENCRYPTION_AES_256;
                    lengthValue = 256;
                }
                else
                    throw new UnsupportedPdfException(MessageLocalization.getComposedMessage("no.compatible.encryption.found"));
                PdfObject em = dic.get(PdfName.ENCRYPTMETADATA);
                if (em != null && em.toString().equals("false"))
                    cryptoMode |= PdfWriter.DO_NOT_ENCRYPT_METADATA;

                recipients = (PdfArray)dic.get(PdfName.RECIPIENTS);
                break;
            default:
            	throw new UnsupportedPdfException(MessageLocalization.getComposedMessage("unknown.encryption.type.v.eq.1", vValue));
            }
            X509CertificateHolder certHolder;
            try {
                certHolder = new X509CertificateHolder(certificate.getEncoded());
            }
            catch (Exception f) {
                throw new ExceptionConverter(f);
            }
            if (externalDecryptionProcess == null) {
                for (int i = 0; i < recipients.size(); i++) {
                    PdfObject recipient = recipients.getPdfObject(i);
                    strings.remove(recipient);

                    CMSEnvelopedData data = null;
                    try {
                        data = new CMSEnvelopedData(recipient.getBytes());

                        Iterator<RecipientInformation> recipientCertificatesIt = data.getRecipientInfos().getRecipients().iterator();

                        while (recipientCertificatesIt.hasNext()) {
                            RecipientInformation recipientInfo = recipientCertificatesIt.next();

                            if (recipientInfo.getRID().match(certHolder) && !foundRecipient) {
                                envelopedData = PdfEncryptor.getContent(recipientInfo, (PrivateKey) certificateKey, certificateKeyProvider);
                                foundRecipient = true;
                            }
                        }

                    } catch (Exception f) {
                        throw new ExceptionConverter(f);
                    }
                }
            } else {
                for (int i = 0; i < recipients.size(); i++) {
                    PdfObject recipient = recipients.getPdfObject(i);
                    strings.remove(recipient);

                    CMSEnvelopedData data = null;
                    try {
                        data = new CMSEnvelopedData(recipient.getBytes());

                        RecipientInformation recipientInfo =
                                data.getRecipientInfos().get(externalDecryptionProcess.getCmsRecipientId());

                        if (recipientInfo != null) {
                            envelopedData =
                                    recipientInfo.getContent(externalDecryptionProcess.getCmsRecipient());
                            foundRecipient = true;
                        }
                    } catch (Exception f) {
                        throw new ExceptionConverter(f);
                    }
                }
            }

            if(!foundRecipient || envelopedData == null) {
                throw new UnsupportedPdfException(MessageLocalization.getComposedMessage("bad.certificate.and.key"));
            }

            MessageDigest md = null;

            try {
                if ((cryptoMode & PdfWriter.ENCRYPTION_MASK)  == PdfWriter.ENCRYPTION_AES_256)
                    md = MessageDigest.getInstance("SHA-256");
                else
                    md = MessageDigest.getInstance("SHA-1");
                md.update(envelopedData, 0, 20);
                for (int i = 0; i<recipients.size(); i++) {
                  byte[] encodedRecipient = recipients.getPdfObject(i).getBytes();
                  md.update(encodedRecipient);
                }
                if ((cryptoMode & PdfWriter.DO_NOT_ENCRYPT_METADATA) != 0)
                    md.update(new byte[]{(byte)255, (byte)255, (byte)255, (byte)255});
                encryptionKey = md.digest();
            }
            catch (Exception f) {
                throw new ExceptionConverter(f);
            }
        }


        decrypt = new PdfEncryption();
        decrypt.setCryptoMode(cryptoMode, lengthValue);

        if (filter.equals(PdfName.STANDARD)) {
            if (rValue == 5) {
                ownerPasswordUsed = decrypt.readKey(enc, password);
                decrypt.documentID = documentID;
                pValue = decrypt.getPermissions();
            }
            else {
                //check by owner password
                decrypt.setupByOwnerPassword(documentID, password, uValue, oValue, pValue);
                if (!equalsArray(uValue, decrypt.userKey, rValue == 3 || rValue == 4 ? 16 : 32)) {
                    //check by user password
                    decrypt.setupByUserPassword(documentID, password, oValue, pValue);
                    if (!equalsArray(uValue, decrypt.userKey, rValue == 3 || rValue == 4 ? 16 : 32)) {
                        throw new BadPasswordException(MessageLocalization.getComposedMessage("bad.user.password"));
                    }
                }
                else
                    ownerPasswordUsed = true;
            }
        }
        else if (filter.equals(PdfName.PUBSEC)) {
            decrypt.documentID = documentID;
            if ((cryptoMode & PdfWriter.ENCRYPTION_MASK) == PdfWriter.ENCRYPTION_AES_256)
                decrypt.setKey(encryptionKey);
            else
                decrypt.setupByEncryptionKey(encryptionKey, lengthValue);
            ownerPasswordUsed = true;
        }

        for (int k = 0; k < strings.size(); ++k) {
            PdfString str = strings.get(k);
            str.decrypt(this);
        }

        if (encDic.isIndirect()) {
            cryptoRef = (PRIndirectReference)encDic;
            xrefObj.set(cryptoRef.getNumber(), null);
        }
        encryptionError = false;
    }

    /**
     * @param obj
     * @return a PdfObject
     */
    public static PdfObject getPdfObjectRelease(final PdfObject obj) {
        PdfObject obj2 = getPdfObject(obj);
        releaseLastXrefPartial(obj);
        return obj2;
    }


    /**
     * Reads a <CODE>PdfObject</CODE> resolving an indirect reference
     * if needed.
     * @param obj the <CODE>PdfObject</CODE> to read
     * @return the resolved <CODE>PdfObject</CODE>
     */
    public static PdfObject getPdfObject(PdfObject obj) {
        if (obj == null)
            return null;
        if (!obj.isIndirect())
            return obj;
        try {
            PRIndirectReference ref = (PRIndirectReference)obj;
            int idx = ref.getNumber();
            boolean appendable = ref.getReader().appendable;
            obj = ref.getReader().getPdfObject(idx);
            if (obj == null) {
                return null;
            }
            else {
                if (appendable) {
                    switch (obj.type()) {
                        case PdfObject.NULL:
                            obj = new PdfNull();
                            break;
                        case PdfObject.BOOLEAN:
                            obj = new PdfBoolean(((PdfBoolean)obj).booleanValue());
                            break;
                        case PdfObject.NAME:
                            obj = new PdfName(obj.getBytes());
                            break;
                    }
                    obj.setIndRef(ref);
                }
                return obj;
            }
        }
        catch (Exception e) {
            throw new ExceptionConverter(e);
        }
    }

    /**
     * Reads a <CODE>PdfObject</CODE> resolving an indirect reference
     * if needed. If the reader was opened in partial mode the object will be released
     * to save memory.
     * @param obj the <CODE>PdfObject</CODE> to read
     * @param parent
     * @return a PdfObject
     */
    public static PdfObject getPdfObjectRelease(final PdfObject obj, final PdfObject parent) {
        PdfObject obj2 = getPdfObject(obj, parent);
        releaseLastXrefPartial(obj);
        return obj2;
    }

    /**
     * @param obj
     * @param parent
     * @return a PdfObject
     */
    public static PdfObject getPdfObject(PdfObject obj, final PdfObject parent) {
        if (obj == null)
            return null;
        if (!obj.isIndirect()) {
            PRIndirectReference ref = null;
            if (parent != null && (ref = parent.getIndRef()) != null && ref.getReader().isAppendable()) {
                switch (obj.type()) {
                    case PdfObject.NULL:
                        obj = new PdfNull();
                        break;
                    case PdfObject.BOOLEAN:
                        obj = new PdfBoolean(((PdfBoolean)obj).booleanValue());
                        break;
                    case PdfObject.NAME:
                        obj = new PdfName(obj.getBytes());
                        break;
                }
                obj.setIndRef(ref);
            }
            return obj;
        }
        return getPdfObject(obj);
    }

    /**
     * @param idx
     * @return a PdfObject
     */
    public PdfObject getPdfObjectRelease(final int idx) {
        PdfObject obj = getPdfObject(idx);
        releaseLastXrefPartial();
        return obj;
    }

    /**
     * @param idx
     * @return aPdfObject
     */
    public PdfObject getPdfObject(final int idx) {
        try {
            lastXrefPartial = -1;
            if (idx < 0 || idx >= xrefObj.size())
                return null;
            PdfObject obj = xrefObj.get(idx);
            if (!partial || obj != null)
                return obj;
            if (idx * 2 >= xref.length)
                return null;
            obj = readSingleObject(idx);
            lastXrefPartial = -1;
            if (obj != null)
                lastXrefPartial = idx;
            return obj;
        }
        catch (Exception e) {
            throw new ExceptionConverter(e);
        }
    }

    /**
     *
     */
    public void resetLastXrefPartial() {
        lastXrefPartial = -1;
    }

    /**
     *
     */
    public void releaseLastXrefPartial() {
        if (partial && lastXrefPartial != -1) {
            xrefObj.set(lastXrefPartial, null);
            lastXrefPartial = -1;
        }
    }

    /**
     * @param obj
     */
    public static void releaseLastXrefPartial(final PdfObject obj) {
        if (obj == null)
            return;
        if (!obj.isIndirect())
            return;
        if (!(obj instanceof PRIndirectReference))
            return;

        PRIndirectReference ref = (PRIndirectReference)obj;
        PdfReader reader = ref.getReader();
        if (reader.partial && reader.lastXrefPartial != -1 && reader.lastXrefPartial == ref.getNumber()) {
            reader.xrefObj.set(reader.lastXrefPartial, null);
        }
        reader.lastXrefPartial = -1;
    }

    private void setXrefPartialObject(final int idx, final PdfObject obj) {
        if (!partial || idx < 0)
            return;
        xrefObj.set(idx, obj);
    }

    /**
     * @param obj
     * @return an indirect reference
     */
    public PRIndirectReference addPdfObject(final PdfObject obj) {
        xrefObj.add(obj);
        return new PRIndirectReference(this, xrefObj.size() - 1);
    }

    protected void readPages() throws IOException {
        catalog = trailer.getAsDict(PdfName.ROOT);
        if (catalog == null) {
            throw new InvalidPdfException(MessageLocalization.getComposedMessage("the.document.has.no.catalog.object"));
        }
        rootPages = catalog.getAsDict(PdfName.PAGES);
        if (rootPages == null || (!PdfName.PAGES.equals(rootPages.get(PdfName.TYPE)) && !PdfName.PAGES.equals(rootPages.get(new PdfName("Types"))))) {
            if (debugmode) {
                if ( LOGGER.isLogging(Level.ERROR) ) {
                    LOGGER.error(MessageLocalization.getComposedMessage("the.document.has.no.page.root"));
                }
            }
            else {
                throw new InvalidPdfException(MessageLocalization.getComposedMessage("the.document.has.no.page.root"));
            }
        }
        pageRefs = new PageRefs(this);
    }

    protected void readDocObjPartial() throws IOException {
        xrefObj = new ArrayList<PdfObject>(xref.length / 2);
        xrefObj.addAll(Collections.<PdfObject>nCopies(xref.length / 2, null));
        readDecryptedDocObj();
        if (objStmToOffset != null) {
            long keys[] = objStmToOffset.getKeys();
            for (int k = 0; k < keys.length; ++k) {
                long n = keys[k];
                objStmToOffset.put(n, xref[(int)(n * 2)]);
                xref[(int)(n * 2)] = -1;
            }
        }
    }

    protected PdfObject readSingleObject(final int k) throws IOException {
        strings.clear();
        int k2 = k * 2;
        long pos = xref[k2];
        if (pos < 0)
            return null;
        if (xref[k2 + 1] > 0)
            pos = objStmToOffset.get(xref[k2 + 1]);
        if (pos == 0)
            return null;
        tokens.seek(pos);
        tokens.nextValidToken();
        if (tokens.getTokenType() != TokenType.NUMBER)
            tokens.throwError(MessageLocalization.getComposedMessage("invalid.object.number"));
        objNum = tokens.intValue();
        tokens.nextValidToken();
        if (tokens.getTokenType() != TokenType.NUMBER)
            tokens.throwError(MessageLocalization.getComposedMessage("invalid.generation.number"));
        objGen = tokens.intValue();
        tokens.nextValidToken();
        if (!tokens.getStringValue().equals("obj"))
            tokens.throwError(MessageLocalization.getComposedMessage("token.obj.expected"));
        PdfObject obj;
        try {
            obj = readPRObject();
            for (int j = 0; j < strings.size(); ++j) {
                PdfString str = strings.get(j);
                str.decrypt(this);
            }
            if (obj.isStream()) {
                checkPRStreamLength((PRStream)obj);
            }
        }
        catch (IOException e) {
        	if (debugmode) {
                if (LOGGER.isLogging(Level.ERROR))
                    LOGGER.error(e.getMessage(), e);
        		obj = null;
        	}
        	else
        		throw e;
        }
        if (xref[k2 + 1] > 0) {
            obj = readOneObjStm((PRStream)obj, (int)xref[k2]);
        }
        xrefObj.set(k, obj);
        return obj;
    }

    protected PdfObject readOneObjStm(final PRStream stream, int idx) throws IOException {
        int first = stream.getAsNumber(PdfName.FIRST).intValue();
        byte b[] = getStreamBytes(stream, tokens.getFile());
        PRTokeniser saveTokens = tokens;
        tokens = new PRTokeniser(new RandomAccessFileOrArray(new RandomAccessSourceFactory().createSource(b)));
        try {
            int address = 0;
            boolean ok = true;
            ++idx;
            for (int k = 0; k < idx; ++k) {
                ok = tokens.nextToken();
                if (!ok)
                    break;
                if (tokens.getTokenType() != TokenType.NUMBER) {
                    ok = false;
                    break;
                }
                ok = tokens.nextToken();
                if (!ok)
                    break;
                if (tokens.getTokenType() != TokenType.NUMBER) {
                    ok = false;
                    break;
                }
                address = tokens.intValue() + first;
            }
            if (!ok)
                throw new InvalidPdfException(MessageLocalization.getComposedMessage("error.reading.objstm"));
            tokens.seek(address);
            tokens.nextToken();
            PdfObject obj;
            if (tokens.getTokenType() == PRTokeniser.TokenType.NUMBER) {
                obj = new PdfNumber(tokens.getStringValue());
            }
            else {
                tokens.seek(address);
                obj = readPRObject();
            }
            return obj;
            //return readPRObject();
        }
        finally {
            tokens = saveTokens;
        }
    }

    /**
     * @return the percentage of the cross reference table that has been read
     */
    public double dumpPerc() {
        int total = 0;
        for (int k = 0; k < xrefObj.size(); ++k) {
            if (xrefObj.get(k) != null)
                ++total;
        }
        return total * 100.0 / xrefObj.size();
    }

    protected void readDocObj() throws IOException {
        ArrayList<PRStream> streams = new ArrayList<PRStream>();
        xrefObj = new ArrayList<PdfObject>(xref.length / 2);
        xrefObj.addAll(Collections.<PdfObject>nCopies(xref.length / 2, null));
        for (int k = 2; k < xref.length; k += 2) {
            long pos = xref[k];
            if (pos <= 0 || xref[k + 1] > 0)
                continue;
            tokens.seek(pos);
            tokens.nextValidToken();
            if (tokens.getTokenType() != TokenType.NUMBER)
                tokens.throwError(MessageLocalization.getComposedMessage("invalid.object.number"));
            objNum = tokens.intValue();
            tokens.nextValidToken();
            if (tokens.getTokenType() != TokenType.NUMBER)
                tokens.throwError(MessageLocalization.getComposedMessage("invalid.generation.number"));
            objGen = tokens.intValue();
            tokens.nextValidToken();
            if (!tokens.getStringValue().equals("obj"))
                tokens.throwError(MessageLocalization.getComposedMessage("token.obj.expected"));
            PdfObject obj;
            try {
                obj = readPRObject();
                if (obj.isStream()) {
                    streams.add((PRStream)obj);
                }
            }
            catch (IOException e) {
            	if (debugmode) {
                    if (LOGGER.isLogging(Level.ERROR))
                        LOGGER.error(e.getMessage(), e);
            		obj = null;
            	}
            	else
            		throw e;
            }
            xrefObj.set(k / 2, obj);
        }
        for (int k = 0; k < streams.size(); ++k) {
            checkPRStreamLength(streams.get(k));
        }
        readDecryptedDocObj();
        if (objStmMark != null) {
            for (Map.Entry<Integer, IntHashtable>entry: objStmMark.entrySet()) {
                int n = entry.getKey().intValue();
                IntHashtable h = entry.getValue();
                readObjStm((PRStream)xrefObj.get(n), h);
                xrefObj.set(n, null);
            }
            objStmMark = null;
        }
        xref = null;
    }

    private void checkPRStreamLength(final PRStream stream) throws IOException {
        long fileLength = tokens.length();
        long start = stream.getOffset();
        boolean calc = false;
        long streamLength = 0;
        PdfObject obj = getPdfObjectRelease(stream.get(PdfName.LENGTH));
        if (obj != null && obj.type() == PdfObject.NUMBER) {
            streamLength = ((PdfNumber)obj).intValue();
            if (streamLength + start > fileLength - 20)
                calc = true;
            else {
                tokens.seek(start + streamLength);
                String line = tokens.readString(20);
                if (!line.startsWith("\nendstream") &&
                !line.startsWith("\r\nendstream") &&
                !line.startsWith("\rendstream") &&
                !line.startsWith("endstream"))
                    calc = true;
            }
        }
        else
            calc = true;
        if (calc) {
            byte tline[] = new byte[16];
            tokens.seek(start);
            long pos;
            while (true) {
                pos = tokens.getFilePointer();
                if (!tokens.readLineSegment(tline, false)) // added boolean because of mailing list issue (17 Feb. 2014)
                    break;
                if (equalsn(tline, endstream)) {
                    streamLength = pos - start;
                    break;
                }
                if (equalsn(tline, endobj)) {
                    tokens.seek(pos - 16);
                    String s = tokens.readString(16);
                    int index = s.indexOf("endstream");
                    if (index >= 0)
                        pos = pos - 16 + index;
                    streamLength = pos - start;
                    break;
                }
            }
            tokens.seek(pos - 2);
            if (tokens.read() == 13)
            	streamLength--;
            tokens.seek(pos - 1);
            if (tokens.read() == 10)
            	streamLength--;

            if ( streamLength < 0 ) {
                streamLength = 0;
            }
        }
        stream.setLength((int)streamLength);
    }

    protected void readObjStm(final PRStream stream, final IntHashtable map) throws IOException {
        if (stream == null) return;
        int first = stream.getAsNumber(PdfName.FIRST).intValue();
        int n = stream.getAsNumber(PdfName.N).intValue();
        byte b[] = getStreamBytes(stream, tokens.getFile());
        PRTokeniser saveTokens = tokens;
        tokens = new PRTokeniser(new RandomAccessFileOrArray(new RandomAccessSourceFactory().createSource(b)));
        try {
            int address[] = new int[n];
            int objNumber[] = new int[n];
            boolean ok = true;
            for (int k = 0; k < n; ++k) {
                ok = tokens.nextToken();
                if (!ok)
                    break;
                if (tokens.getTokenType() != TokenType.NUMBER) {
                    ok = false;
                    break;
                }
                objNumber[k] = tokens.intValue();
                ok = tokens.nextToken();
                if (!ok)
                    break;
                if (tokens.getTokenType() != TokenType.NUMBER) {
                    ok = false;
                    break;
                }
                address[k] = tokens.intValue() + first;
            }
            if (!ok)
                throw new InvalidPdfException(MessageLocalization.getComposedMessage("error.reading.objstm"));
            for (int k = 0; k < n; ++k) {
                if (map.containsKey(k)) {
                    tokens.seek(address[k]);
                    tokens.nextToken();
                    PdfObject obj;
                    if (tokens.getTokenType() == PRTokeniser.TokenType.NUMBER) {
                    	obj = new PdfNumber(tokens.getStringValue());
                    }
                    else {
                    	tokens.seek(address[k]);
                    	obj = readPRObject();
                    }
                    xrefObj.set(objNumber[k], obj);
                }
            }
        }
        finally {
            tokens = saveTokens;
        }
    }

    /**
     * Eliminates the reference to the object freeing the memory used by it and clearing
     * the xref entry.
     * @param obj the object. If it's an indirect reference it will be eliminated
     * @return the object or the already erased dereferenced object
     */
    public static PdfObject killIndirect(final PdfObject obj) {
        if (obj == null || obj.isNull())
            return null;
        PdfObject ret = getPdfObjectRelease(obj);
        if (obj.isIndirect()) {
            PRIndirectReference ref = (PRIndirectReference)obj;
            PdfReader reader = ref.getReader();
            int n = ref.getNumber();
            reader.xrefObj.set(n, null);
            if (reader.partial)
                reader.xref[n * 2] = -1;
        }
        return ret;
    }

    private void ensureXrefSize(final int size) {
        if (size == 0)
            return;
        if (xref == null)
            xref = new long[size];
        else {
            if (xref.length < size) {
                long xref2[] = new long[size];
                System.arraycopy(xref, 0, xref2, 0, xref.length);
                xref = xref2;
            }
        }
    }

    protected void readXref() throws IOException {
        hybridXref = false;
        newXrefType = false;
        tokens.seek(tokens.getStartxref());
        tokens.nextToken();
        if (!tokens.getStringValue().equals("startxref"))
            throw new InvalidPdfException(MessageLocalization.getComposedMessage("startxref.not.found"));
        tokens.nextToken();
        if (tokens.getTokenType() != TokenType.NUMBER)
            throw new InvalidPdfException(MessageLocalization.getComposedMessage("startxref.is.not.followed.by.a.number"));
        long startxref = tokens.longValue();
        lastXref = startxref;
        eofPos = tokens.getFilePointer();
        try {
            if (readXRefStream(startxref)) {
                newXrefType = true;
                return;
            }
        }
        catch (Exception e) {}
        xref = null;
        tokens.seek(startxref);
        trailer = readXrefSection();
        PdfDictionary trailer2 = trailer;
        while (true) {
            PdfNumber prev = (PdfNumber)trailer2.get(PdfName.PREV);
            if (prev == null)
                break;
            if (prev.longValue() == startxref)
                throw new InvalidPdfException(MessageLocalization.getComposedMessage("trailer.prev.entry.points.to.its.own.cross.reference.section"));
            startxref = prev.longValue();
            tokens.seek(startxref);
            trailer2 = readXrefSection();
        }
    }

    protected PdfDictionary readXrefSection() throws IOException {
        tokens.nextValidToken();
        if (!tokens.getStringValue().equals("xref"))
            tokens.throwError(MessageLocalization.getComposedMessage("xref.subsection.not.found"));
        int start = 0;
        int end = 0;
        long pos = 0;
        int gen = 0;
        while (true) {
            tokens.nextValidToken();
            if (tokens.getStringValue().equals("trailer"))
                break;
            if (tokens.getTokenType() != TokenType.NUMBER)
                tokens.throwError(MessageLocalization.getComposedMessage("object.number.of.the.first.object.in.this.xref.subsection.not.found"));
            start = tokens.intValue();
            tokens.nextValidToken();
            if (tokens.getTokenType() != TokenType.NUMBER)
                tokens.throwError(MessageLocalization.getComposedMessage("number.of.entries.in.this.xref.subsection.not.found"));
            end = tokens.intValue() + start;
            if (start == 1) { // fix incorrect start number
                long back = tokens.getFilePointer();
                tokens.nextValidToken();
                pos = tokens.longValue();
                tokens.nextValidToken();
                gen = tokens.intValue();
                if (pos == 0 && gen == PdfWriter.GENERATION_MAX) {
                    --start;
                    --end;
                }
                tokens.seek(back);
            }
            ensureXrefSize(end * 2);
            for (int k = start; k < end; ++k) {
                tokens.nextValidToken();
                pos = tokens.longValue();
                tokens.nextValidToken();
                gen = tokens.intValue();
                tokens.nextValidToken();
                int p = k * 2;
                if (tokens.getStringValue().equals("n")) {
                    if (xref[p] == 0 && xref[p + 1] == 0) {
//                        if (pos == 0)
//                            tokens.throwError(MessageLocalization.getComposedMessage("file.position.0.cross.reference.entry.in.this.xref.subsection"));
                        xref[p] = pos;
                    }
                }
                else if (tokens.getStringValue().equals("f")) {
                    if (xref[p] == 0 && xref[p + 1] == 0)
                        xref[p] = -1;
                }
                else
                    tokens.throwError(MessageLocalization.getComposedMessage("invalid.cross.reference.entry.in.this.xref.subsection"));
            }
        }
        PdfDictionary trailer = (PdfDictionary)readPRObject();
        PdfNumber xrefSize = (PdfNumber)trailer.get(PdfName.SIZE);
        ensureXrefSize(xrefSize.intValue() * 2);
        PdfObject xrs = trailer.get(PdfName.XREFSTM);
        if (xrs != null && xrs.isNumber()) {
            int loc = ((PdfNumber)xrs).intValue();
            try {
                readXRefStream(loc);
                newXrefType = true;
                hybridXref = true;
            }
            catch (IOException e) {
                xref = null;
                throw e;
            }
        }
        return trailer;
    }

    protected boolean readXRefStream(final long ptr) throws IOException {
        tokens.seek(ptr);
        int thisStream = 0;
        if (!tokens.nextToken())
            return false;
        if (tokens.getTokenType() != TokenType.NUMBER)
            return false;
        thisStream = tokens.intValue();
        if (!tokens.nextToken() || tokens.getTokenType() != TokenType.NUMBER)
            return false;
        if (!tokens.nextToken() || !tokens.getStringValue().equals("obj"))
            return false;
        PdfObject object = readPRObject();
        PRStream stm = null;
        if (object.isStream()) {
            stm = (PRStream)object;
            if (!PdfName.XREF.equals(stm.get(PdfName.TYPE)))
                return false;
        }
        else
            return false;
        if (trailer == null) {
            trailer = new PdfDictionary();
            trailer.putAll(stm);
        }
        stm.setLength(((PdfNumber)stm.get(PdfName.LENGTH)).intValue());
        int size = ((PdfNumber)stm.get(PdfName.SIZE)).intValue();
        PdfArray index;
        PdfObject obj = stm.get(PdfName.INDEX);
        if (obj == null) {
            index = new PdfArray();
            index.add(new int[]{0, size});
        }
        else
            index = (PdfArray)obj;
        PdfArray w = (PdfArray)stm.get(PdfName.W);
        long prev = -1;
        obj = stm.get(PdfName.PREV);
        if (obj != null)
            prev = ((PdfNumber)obj).longValue();
        // Each xref pair is a position
        // type 0 -> -1, 0
        // type 1 -> offset, 0
        // type 2 -> index, obj num
        ensureXrefSize(size * 2);
        if (objStmMark == null && !partial)
            objStmMark = new HashMap<Integer, IntHashtable>();
        if (objStmToOffset == null && partial)
            objStmToOffset = new LongHashtable();
        byte b[] = getStreamBytes(stm, tokens.getFile());
        int bptr = 0;
        int wc[] = new int[3];
        for (int k = 0; k < 3; ++k)
            wc[k] = w.getAsNumber(k).intValue();
        for (int idx = 0; idx < index.size(); idx += 2) {
            int start = index.getAsNumber(idx).intValue();
            int length = index.getAsNumber(idx + 1).intValue();
            ensureXrefSize((start + length) * 2);
            while (length-- > 0) {
                int type = 1;
                if (wc[0] > 0) {
                    type = 0;
                    for (int k = 0; k < wc[0]; ++k)
                        type = (type << 8) + (b[bptr++] & 0xff);
                }
                long field2 = 0;
                for (int k = 0; k < wc[1]; ++k)
                    field2 = (field2 << 8) + (b[bptr++] & 0xff);
                int field3 = 0;
                for (int k = 0; k < wc[2]; ++k)
                    field3 = (field3 << 8) + (b[bptr++] & 0xff);
                int base = start * 2;
                if (xref[base] == 0 && xref[base + 1] == 0) {
                    switch (type) {
                        case 0:
                            xref[base] = -1;
                            break;
                        case 1:
                            xref[base] = field2;
                            break;
                        case 2:
                            xref[base] = field3;
                            xref[base + 1] = field2;
                            if (partial) {
                                objStmToOffset.put(field2, 0);
                            }
                            else {
                                Integer on = Integer.valueOf((int)field2);
                                IntHashtable seq = objStmMark.get(on);
                                if (seq == null) {
                                    seq = new IntHashtable();
                                    seq.put(field3, 1);
                                    objStmMark.put(on, seq);
                                }
                                else
                                    seq.put(field3, 1);
                            }
                            break;
                    }
                }
                ++start;
            }
        }
        thisStream *= 2;
        if (thisStream + 1 < xref.length && xref[thisStream] == 0 && xref[thisStream + 1] == 0)
            xref[thisStream] = -1;

        if (prev == -1)
            return true;
        return readXRefStream(prev);
    }

    protected void rebuildXref() throws IOException {
        hybridXref = false;
        newXrefType = false;
        tokens.seek(0);
        long xr[][] = new long[1024][];
        long top = 0;
        trailer = null;
        byte line[] = new byte[64];
        for (;;) {
            long pos = tokens.getFilePointer();
            if (!tokens.readLineSegment(line, true)) // added boolean because of mailing list issue (17 Feb. 2014)
                break;
            if (line[0] == 't') {
                if (!PdfEncodings.convertToString(line, null).startsWith("trailer"))
                    continue;
                tokens.seek(pos);
                tokens.nextToken();
                pos = tokens.getFilePointer();
                try {
                    PdfDictionary dic = (PdfDictionary)readPRObject();
                    if (dic.get(PdfName.ROOT) != null)
                        trailer = dic;
                    else
                        tokens.seek(pos);
                }
                catch (Exception e) {
                    tokens.seek(pos);
                }
            }
            else if (line[0] >= '0' && line[0] <= '9') {
                long obj[] = PRTokeniser.checkObjectStart(line);
                if (obj == null)
                    continue;
                long num = obj[0];
                long gen = obj[1];
                if (num >= xr.length) {
                    long newLength = num * 2;
                    long xr2[][] = new long[(int)newLength][];
                    System.arraycopy(xr, 0, xr2, 0, (int)top);
                    xr = xr2;
                }
                if (num >= top)
                    top = num + 1;
                if (xr[(int)num] == null || gen >= xr[(int)num][1]) {
                    obj[0] = pos;
                    xr[(int)num] = obj;
                }
            }
        }
        if (trailer == null)
            throw new InvalidPdfException(MessageLocalization.getComposedMessage("trailer.not.found"));
        xref = new long[(int)(top * 2)];
        for (int k = 0; k < top; ++k) {
            long obj[] = xr[k];
            if (obj != null)
                xref[k * 2] = obj[0];
        }
    }

    protected PdfDictionary readDictionary() throws IOException {
        PdfDictionary dic = new PdfDictionary();
        while (true) {
            tokens.nextValidToken();
            if (tokens.getTokenType() == TokenType.END_DIC)
                break;
            if (tokens.getTokenType() != TokenType.NAME)
                tokens.throwError(MessageLocalization.getComposedMessage("dictionary.key.1.is.not.a.name", tokens.getStringValue()));
            PdfName name = new PdfName(tokens.getStringValue(), false);
            PdfObject obj = readPRObject();
            int type = obj.type();
            if (-type == TokenType.END_DIC.ordinal())
                tokens.throwError(MessageLocalization.getComposedMessage("unexpected.gt.gt"));
            if (-type == TokenType.END_ARRAY.ordinal())
                tokens.throwError(MessageLocalization.getComposedMessage("unexpected.close.bracket"));
            dic.put(name, obj);
        }
        return dic;
    }

    protected PdfArray readArray() throws IOException {
        PdfArray array = new PdfArray();
        while (true) {
            PdfObject obj = readPRObject();
            int type = obj.type();
            if (-type == TokenType.END_ARRAY.ordinal())
                break;
            if (-type == TokenType.END_DIC.ordinal())
                tokens.throwError(MessageLocalization.getComposedMessage("unexpected.gt.gt"));
            array.add(obj);
        }
        return array;
    }

    // Track how deeply nested the current object is, so
    // we know when to return an individual null or boolean, or
    // reuse one of the static ones.
    private int readDepth = 0;

    protected PdfObject readPRObject() throws IOException {
        tokens.nextValidToken();
        TokenType type = tokens.getTokenType();
        switch (type) {
            case START_DIC: {
                ++readDepth;
                PdfDictionary dic = readDictionary();
                --readDepth;
                long pos = tokens.getFilePointer();
                // be careful in the trailer. May not be a "next" token.
                boolean hasNext;
                do {
                    hasNext = tokens.nextToken();
                } while (hasNext && tokens.getTokenType() == TokenType.COMMENT);

                if (hasNext && tokens.getStringValue().equals("stream")) {
                    //skip whitespaces
                    int ch;
                    do {
                        ch = tokens.read();
                    } while (ch == 32 || ch == 9 || ch == 0 || ch == 12);
                    if (ch != '\n')
                        ch = tokens.read();
                    if (ch != '\n')
                        tokens.backOnePosition(ch);
                    PRStream stream = new PRStream(this, tokens.getFilePointer());
                    stream.putAll(dic);
                    // crypto handling
                    stream.setObjNum(objNum, objGen);

                    return stream;
                }
                else {
                    tokens.seek(pos);
                    return dic;
                }
            }
            case START_ARRAY: {
                ++readDepth;
                PdfArray arr = readArray();
                --readDepth;
                return arr;
            }
            case NUMBER:
                return new PdfNumber(tokens.getStringValue());
            case STRING:
                PdfString str = new PdfString(tokens.getStringValue(), null).setHexWriting(tokens.isHexString());
                // crypto handling
                str.setObjNum(objNum, objGen);
                if (strings != null)
                    strings.add(str);

                return str;
            case NAME: {
                PdfName cachedName = PdfName.staticNames.get( tokens.getStringValue() );
                if (readDepth > 0 && cachedName != null) {
                    return cachedName;
                } else {
                    // an indirect name (how odd...), or a non-standard one
                    return new PdfName(tokens.getStringValue(), false);
                }
            }
            case REF: {
                int num = tokens.getReference();
                if (num >= 0) {
                    return new PRIndirectReference(this, num, tokens.getGeneration());
                } else {
                    if (LOGGER.isLogging(Level.ERROR)) {
                        LOGGER.error(MessageLocalization.getComposedMessage("invalid.reference.number.skip"));
                    }
                    return PdfNull.PDFNULL;
                }
            }
            case ENDOFFILE:
                throw new IOException(MessageLocalization.getComposedMessage("unexpected.end.of.file"));
            default:
                String sv = tokens.getStringValue();
                if ("null".equals(sv)) {
                    if (readDepth == 0) {
                        return new PdfNull();
                    } //else
                    return PdfNull.PDFNULL;
                }
                else if ("true".equals(sv)) {
                    if (readDepth == 0) {
                        return new PdfBoolean( true );
                    } //else
                    return PdfBoolean.PDFTRUE;
                }
                else if ("false".equals(sv)) {
                    if (readDepth == 0) {
                        return new PdfBoolean( false );
                    } //else
                    return PdfBoolean.PDFFALSE;
                }
                return new PdfLiteral(-type.ordinal(), tokens.getStringValue());
        }
    }

    /** Decodes a stream that has the FlateDecode filter.
     * @param in the input data
     * @return the decoded data
     */
    public static byte[] FlateDecode(final byte in[]) {
        byte b[] = FlateDecode(in, true);
        if (b == null)
            return FlateDecode(in, false);
        return b;
    }

    /** Decodes a stream that has the FlateDecode filter.
     * @param in the input data
     * @return the decoded data
     */
    static byte[] FlateDecode(final byte in[], ByteArrayOutputStream out) {
        byte b[] = FlateDecode(in, true, out);
        if (b == null)
            return FlateDecode(in, false, out);
        return b;
    }

    /**
     * @param in
     * @param dicPar
     * @return a byte array
     */
    public static byte[] decodePredictor(final byte in[], final PdfObject dicPar) {
        if (dicPar == null || !dicPar.isDictionary())
            return in;
        PdfDictionary dic = (PdfDictionary)dicPar;
        PdfObject obj = getPdfObject(dic.get(PdfName.PREDICTOR));
        if (obj == null || !obj.isNumber())
            return in;
        int predictor = ((PdfNumber)obj).intValue();
        if (predictor < 10 && predictor != 2)
            return in;
        int width = 1;
        obj = getPdfObject(dic.get(PdfName.COLUMNS));
        if (obj != null && obj.isNumber())
            width = ((PdfNumber)obj).intValue();
        int colors = 1;
        obj = getPdfObject(dic.get(PdfName.COLORS));
        if (obj != null && obj.isNumber())
            colors = ((PdfNumber)obj).intValue();
        int bpc = 8;
        obj = getPdfObject(dic.get(PdfName.BITSPERCOMPONENT));
        if (obj != null && obj.isNumber())
            bpc = ((PdfNumber)obj).intValue();
        DataInputStream dataStream = new DataInputStream(new ByteArrayInputStream(in));
        ByteArrayOutputStream fout = new ByteArrayOutputStream(in.length);
        int bytesPerPixel = colors * bpc / 8;
        int bytesPerRow = (colors*width*bpc + 7)/8;
        byte[] curr = new byte[bytesPerRow];
        byte[] prior = new byte[bytesPerRow];
        if (predictor == 2) {
			if (bpc == 8) {
				int numRows = in.length / bytesPerRow;
				for (int row = 0; row < numRows; row++) {
					int rowStart = row * bytesPerRow;
					for (int col = 0 + bytesPerPixel; col < bytesPerRow; col++) {
						in[rowStart + col] = (byte)(in[rowStart + col] + in[rowStart + col - bytesPerPixel]);
					}
				}
			}
			return in;
		}
        // Decode the (sub)image row-by-row
        while (true) {
            // Read the filter type byte and a row of data
            int filter = 0;
            try {
                filter = dataStream.read();
                if (filter < 0) {
                    return fout.toByteArray();
                }
                dataStream.readFully(curr, 0, bytesPerRow);
            } catch (Exception e) {
                return fout.toByteArray();
            }

            switch (filter) {
                case 0: //PNG_FILTER_NONE
                    break;
                case 1: //PNG_FILTER_SUB
                    for (int i = bytesPerPixel; i < bytesPerRow; i++) {
                        curr[i] += curr[i - bytesPerPixel];
                    }
                    break;
                case 2: //PNG_FILTER_UP
                    for (int i = 0; i < bytesPerRow; i++) {
                        curr[i] += prior[i];
                    }
                    break;
                case 3: //PNG_FILTER_AVERAGE
                    for (int i = 0; i < bytesPerPixel; i++) {
                        curr[i] += prior[i] / 2;
                    }
                    for (int i = bytesPerPixel; i < bytesPerRow; i++) {
                        curr[i] += ((curr[i - bytesPerPixel] & 0xff) + (prior[i] & 0xff))/2;
                    }
                    break;
                case 4: //PNG_FILTER_PAETH
                    for (int i = 0; i < bytesPerPixel; i++) {
                        curr[i] += prior[i];
                    }

                    for (int i = bytesPerPixel; i < bytesPerRow; i++) {
                        int a = curr[i - bytesPerPixel] & 0xff;
                        int b = prior[i] & 0xff;
                        int c = prior[i - bytesPerPixel] & 0xff;

                        int p = a + b - c;
                        int pa = Math.abs(p - a);
                        int pb = Math.abs(p - b);
                        int pc = Math.abs(p - c);

                        int ret;

                        if (pa <= pb && pa <= pc) {
                            ret = a;
                        } else if (pb <= pc) {
                            ret = b;
                        } else {
                            ret = c;
                        }
                        curr[i] += (byte)ret;
                    }
                    break;
                default:
                    // Error -- unknown filter type
                    throw new RuntimeException(MessageLocalization.getComposedMessage("png.filter.unknown"));
            }
            try {
                fout.write(curr);
            }
            catch (IOException ioe) {
                // Never happens
            }

            // Swap curr and prior
            byte[] tmp = prior;
            prior = curr;
            curr = tmp;
        }
    }

    /** A helper to FlateDecode.
     * @param in the input data
     * @param strict <CODE>true</CODE> to read a correct stream. <CODE>false</CODE>
     * to try to read a corrupted stream
     * @return the decoded data
     */
    public static byte[] FlateDecode(final byte in[], final boolean strict) {
        return FlateDecode(in, strict, new ByteArrayOutputStream());
    }

    private static byte[] FlateDecode(final byte in[], final boolean strict, ByteArrayOutputStream out) {
        ByteArrayInputStream stream = new ByteArrayInputStream(in);
        InflaterInputStream zip = new InflaterInputStream(stream);
        byte b[] = new byte[strict ? 4092 : 1];
        try {
            int n;
            while ((n = zip.read(b)) >= 0) {
                out.write(b, 0, n);
            }
            zip.close();
            out.close();
            return out.toByteArray();
        } catch (MemoryLimitsAwareException e) {
            throw e;
        } catch (Exception e) {
            if (strict)
                return null;
            return out.toByteArray();
        }
        finally {
            try {
                zip.close();
            } catch (IOException ex) {
            }
            try {
                out.close();
            } catch (IOException ex) {
            }
        }
    }

    /** Decodes a stream that has the ASCIIHexDecode filter.
     * @param in the input data
     * @return the decoded data
     */
    public static byte[] ASCIIHexDecode(final byte in[]) {
        return ASCIIHexDecode(in, new ByteArrayOutputStream());
    }

    static byte[] ASCIIHexDecode(final byte in[], ByteArrayOutputStream out) {
        boolean first = true;
        int n1 = 0;
        for (int k = 0; k < in.length; ++k) {
            int ch = in[k] & 0xff;
            if (ch == '>')
                break;
            if (PRTokeniser.isWhitespace(ch))
                continue;
            int n = PRTokeniser.getHex(ch);
            if (n == -1)
                throw new RuntimeException(MessageLocalization.getComposedMessage("illegal.character.in.asciihexdecode"));
            if (first)
                n1 = n;
            else
                out.write((byte)((n1 << 4) + n));
            first = !first;
        }
        if (!first)
            out.write((byte)(n1 << 4));
        return out.toByteArray();
    }

    /** Decodes a stream that has the ASCII85Decode filter.
     * @param in the input data
     * @return the decoded data
     */
    public static byte[] ASCII85Decode(final byte in[]) {
        return ASCII85Decode(in, new ByteArrayOutputStream());
    }

    static byte[] ASCII85Decode(final byte in[], ByteArrayOutputStream out) {
        int state = 0;
        int chn[] = new int[5];
        for (int k = 0; k < in.length; ++k) {
            int ch = in[k] & 0xff;
            if (ch == '~')
                break;
            if (PRTokeniser.isWhitespace(ch))
                continue;
            if (ch == 'z' && state == 0) {
                out.write(0);
                out.write(0);
                out.write(0);
                out.write(0);
                continue;
            }
            if (ch < '!' || ch > 'u')
                throw new RuntimeException(MessageLocalization.getComposedMessage("illegal.character.in.ascii85decode"));
            chn[state] = ch - '!';
            ++state;
            if (state == 5) {
                state = 0;
                int r = 0;
                for (int j = 0; j < 5; ++j)
                    r = r * 85 + chn[j];
                out.write((byte)(r >> 24));
                out.write((byte)(r >> 16));
                out.write((byte)(r >> 8));
                out.write((byte)r);
            }
        }
        int r = 0;
        // We'll ignore the next two lines for the sake of perpetuating broken PDFs
//        if (state == 1)
//            throw new RuntimeException(MessageLocalization.getComposedMessage("illegal.length.in.ascii85decode"));
        if (state == 2) {
            r = chn[0] * 85 * 85 * 85 * 85 + chn[1] * 85 * 85 * 85 + 85 * 85 * 85  + 85 * 85 + 85;
            out.write((byte)(r >> 24));
        }
        else if (state == 3) {
            r = chn[0] * 85 * 85 * 85 * 85 + chn[1] * 85 * 85 * 85  + chn[2] * 85 * 85 + 85 * 85 + 85;
            out.write((byte)(r >> 24));
            out.write((byte)(r >> 16));
        }
        else if (state == 4) {
            r = chn[0] * 85 * 85 * 85 * 85 + chn[1] * 85 * 85 * 85  + chn[2] * 85 * 85  + chn[3] * 85 + 85;
            out.write((byte)(r >> 24));
            out.write((byte)(r >> 16));
            out.write((byte)(r >> 8));
        }
        return out.toByteArray();
    }

    /** Decodes a stream that has the LZWDecode filter.
     * @param in the input data
     * @return the decoded data
     */
    public static byte[] LZWDecode(final byte in[]) {
        return LZWDecode(in, new ByteArrayOutputStream());
    }

    static byte[] LZWDecode(final byte in[], ByteArrayOutputStream out) {
        LZWDecoder lzw = new LZWDecoder();
        lzw.decode(in, out);
        return out.toByteArray();
    }

    /** Checks if the document had errors and was rebuilt.
     * @return true if rebuilt.
     *
     */
    public boolean isRebuilt() {
        return this.rebuilt;
    }

    /** Gets the dictionary that represents a page.
     * @param pageNum the page number. 1 is the first
     * @return the page dictionary
     */
    public PdfDictionary getPageN(final int pageNum) {
        PdfDictionary dic = pageRefs.getPageN(pageNum);
        if (dic == null)
            return null;
        if (appendable)
            dic.setIndRef(pageRefs.getPageOrigRef(pageNum));
        return dic;
    }

    /**
     * @param pageNum
     * @return a Dictionary object
     */
    public PdfDictionary getPageNRelease(final int pageNum) {
        PdfDictionary dic = getPageN(pageNum);
        pageRefs.releasePage(pageNum);
        return dic;
    }

    /**
     * @param pageNum
     */
    public void releasePage(final int pageNum) {
        pageRefs.releasePage(pageNum);
    }

    /**
     *
     */
    public void resetReleasePage() {
        pageRefs.resetReleasePage();
    }

    /** Gets the page reference to this page.
     * @param pageNum the page number. 1 is the first
     * @return the page reference
     */
    public PRIndirectReference getPageOrigRef(final int pageNum) {
        return pageRefs.getPageOrigRef(pageNum);
    }

    /** Gets the contents of the page.
     * @param pageNum the page number. 1 is the first
     * @param file the location of the PDF document
     * @throws IOException on error
     * @return the content
     */
    public byte[] getPageContent(final int pageNum, final RandomAccessFileOrArray file) throws IOException{
        PdfDictionary page = getPageNRelease(pageNum);
        if (page == null)
            return null;
        PdfObject contents = getPdfObjectRelease(page.get(PdfName.CONTENTS));
        if (contents == null)
            return new byte[0];
        MemoryLimitsAwareHandler handler = memoryLimitsAwareHandler;
        long usedMemory = null == handler ? -1 : handler.getAllMemoryUsedForDecompression();

        if (contents.isStream()) {
            return getStreamBytes((PRStream)contents, file);
        }
        else if (contents.isArray()) {
            PdfArray array = (PdfArray)contents;
            MemoryLimitsAwareOutputStream bout = new MemoryLimitsAwareOutputStream();
            for (int k = 0; k < array.size(); ++k) {
                PdfObject item = getPdfObjectRelease(array.getPdfObject(k));
                if (item == null || !item.isStream())
                    continue;
                byte[] b = getStreamBytes((PRStream)item, file);
                // usedMemory has changed, that means that some of currently processed pdf streams are suspicious
                if (null != handler && usedMemory < handler.getAllMemoryUsedForDecompression()) {
                    bout.setMaxStreamSize(handler.getMaxSizeOfSingleDecompressedPdfStream());
                }
                bout.write(b);
                if (k != array.size() - 1)
                    bout.write('\n');
            }
            return bout.toByteArray();
        }
        else
            return new byte[0];
    }

    /** Gets the content from the page dictionary.
     * @param page the page dictionary
     * @throws IOException on error
     * @return the content
     * @since 5.0.6
     */
    public static byte[] getPageContent(final PdfDictionary page) throws IOException{
        if (page == null)
            return null;
        RandomAccessFileOrArray rf = null;
        try {
            PdfObject contents = getPdfObjectRelease(page.get(PdfName.CONTENTS));
            if (contents == null)
                return new byte[0];
            if (contents.isStream()) {
                if (rf == null) {
                    rf = ((PRStream)contents).getReader().getSafeFile();
                    rf.reOpen();
                }
                return getStreamBytes((PRStream)contents, rf);
            }
            else if (contents.isArray()) {
                PdfArray array = (PdfArray)contents;
                ByteArrayOutputStream bout = new ByteArrayOutputStream();
                for (int k = 0; k < array.size(); ++k) {
                    PdfObject item = getPdfObjectRelease(array.getPdfObject(k));
                    if (item == null || !item.isStream())
                        continue;
                    if (rf == null) {
                        rf = ((PRStream)item).getReader().getSafeFile();
                        rf.reOpen();
                    }
                    byte[] b = getStreamBytes((PRStream)item, rf);
                    bout.write(b);
                    if (k != array.size() - 1)
                        bout.write('\n');
                }
                return bout.toByteArray();
            }
            else
                return new byte[0];
        }
        finally {
            try {
                if (rf != null)
                    rf.close();
            }catch(Exception e){}
        }
    }

    /**
     * Retrieve the given page's resource dictionary
     * @param pageNum 1-based page number from which to retrieve the resource dictionary
     * @return The page's resources, or 'null' if the page has none.
     * @since 5.1
     */
    public PdfDictionary getPageResources(final int pageNum) {
        return getPageResources(getPageN(pageNum));
    }

    /**
     * Retrieve the given page's resource dictionary
     * @param pageDict the given page
     * @return The page's resources, or 'null' if the page has none.
     * @since 5.1
     */
    public PdfDictionary getPageResources(final PdfDictionary pageDict) {
    	return pageDict.getAsDict(PdfName.RESOURCES);
    }

    /** Gets the contents of the page.
     * @param pageNum the page number. 1 is the first
     * @throws IOException on error
     * @return the content
     */
    public byte[] getPageContent(final int pageNum) throws IOException{
        RandomAccessFileOrArray rf = getSafeFile();
        try {
            rf.reOpen();
            return getPageContent(pageNum, rf);
        }
        finally {
            try{rf.close();}catch(Exception e){}
        }
    }

    protected void killXref(PdfObject obj) {
        if (obj == null)
            return;
        if (obj instanceof PdfIndirectReference && !obj.isIndirect())
            return;
        switch (obj.type()) {
            case PdfObject.INDIRECT: {
                int xr = ((PRIndirectReference)obj).getNumber();
                obj = xrefObj.get(xr);
                xrefObj.set(xr, null);
                freeXref = xr;
                killXref(obj);
                break;
            }
            case PdfObject.ARRAY: {
                PdfArray t = (PdfArray)obj;
                for (int i = 0; i < t.size(); ++i)
                    killXref(t.getPdfObject(i));
                break;
            }
            case PdfObject.STREAM:
            case PdfObject.DICTIONARY: {
                PdfDictionary dic = (PdfDictionary)obj;
                for (Object element : dic.getKeys()) {
                    killXref(dic.get((PdfName)element));
                }
                break;
            }
        }
    }

    /** Sets the contents of the page.
     * @param content the new page content
     * @param pageNum the page number. 1 is the first
     */
    public void setPageContent(final int pageNum, final byte content[]) {
    	setPageContent(pageNum, content, PdfStream.DEFAULT_COMPRESSION);
    }

    /** Sets the contents of the page.
     * @param content the new page content
     * @param pageNum the page number. 1 is the first
     * @param compressionLevel the compressionLevel
     * @since	2.1.3	(the method already existed without param compressionLevel)
     */
    public void setPageContent(final int pageNum, final byte content[], final int compressionLevel) {
        setPageContent(pageNum, content, compressionLevel, false);
    }

    /** Sets the contents of the page.
     * @param content the new page content
     * @param pageNum the page number. 1 is the first
     * @param compressionLevel the compressionLevel
     * @param killOldXRefRecursively if true, old contents will be deeply removed from the pdf (i.e. if it was an array,
     *                               all its entries will also be removed). Use careful when a content stream may be reused.
     *                               If false, old contents will not be removed and will stay in the document if not manually deleted.
     * @since	5.5.7	(the method already existed without param killOldXRefRecursively)
     */
    public void setPageContent(final int pageNum, final byte content[], final int compressionLevel, final boolean killOldXRefRecursively) {
        PdfDictionary page = getPageN(pageNum);
        if (page == null)
            return;
        PdfObject contents = page.get(PdfName.CONTENTS);
        freeXref = -1;
        if (killOldXRefRecursively) {
            killXref(contents);
        }
        if (freeXref == -1) {
            xrefObj.add(null);
            freeXref = xrefObj.size() - 1;
        }
        page.put(PdfName.CONTENTS, new PRIndirectReference(this, freeXref));
        xrefObj.set(freeXref, new PRStream(this, content, compressionLevel));
    }
    
    /**
     * Decode a byte[] applying the filters specified in the provided dictionary using default filter handlers.
     * @param b the bytes to decode
     * @param streamDictionary the dictionary that contains filter information
     * @return the decoded bytes
     * @throws IOException if there are any problems decoding the bytes
     * @since 5.0.4
     */
    public static byte[] decodeBytes(byte[] b, final PdfDictionary streamDictionary) throws IOException {
        return decodeBytes(b, streamDictionary, FilterHandlers.getDefaultFilterHandlers());
    }
    
    /**
     * Decode a byte[] applying the filters specified in the provided dictionary using the provided filter handlers.
     * @param b the bytes to decode
     * @param streamDictionary the dictionary that contains filter information
     * @param filterHandlers the map used to look up a handler for each type of filter
     * @return the decoded bytes
     * @throws IOException if there are any problems decoding the bytes
     * @since 5.0.4
     */
    public static byte[] decodeBytes(byte[] b, final PdfDictionary streamDictionary, Map<PdfName, FilterHandlers.FilterHandler> filterHandlers) throws IOException {
        PdfObject filter = getPdfObjectRelease(streamDictionary.get(PdfName.FILTER));

        ArrayList<PdfObject> filters = new ArrayList<PdfObject>();
        if (filter != null) {
            if (filter.isName())
                filters.add(filter);
            else if (filter.isArray())
                filters = ((PdfArray)filter).getArrayList();
        }

        MemoryLimitsAwareHandler memoryLimitsAwareHandler = null;
        if (streamDictionary instanceof PRStream && null != ((PRStream) streamDictionary).getReader()) {
            memoryLimitsAwareHandler = ((PRStream) streamDictionary).getReader().getMemoryLimitsAwareHandler();
        }
        if (null != memoryLimitsAwareHandler) {
            HashSet<PdfName> filterSet = new HashSet<PdfName>();
            int index;
            for (index = 0; index < filters.size(); index++) {
                PdfName filterName = (PdfName) filters.get(index);
                if (!filterSet.add(filterName)) {
                    memoryLimitsAwareHandler.beginDecompressedPdfStreamProcessing();
                    break;
                }
            }
            if (index == filters.size()) { // The stream isn't suspicious. We shouldn't process it.
                memoryLimitsAwareHandler = null;
            }
        }

        ArrayList<PdfObject> dp = new ArrayList<PdfObject>();
        PdfObject dpo = getPdfObjectRelease(streamDictionary.get(PdfName.DECODEPARMS));
        if (dpo == null || !dpo.isDictionary() && !dpo.isArray())
            dpo = getPdfObjectRelease(streamDictionary.get(PdfName.DP));
        if (dpo != null) {
            if (dpo.isDictionary())
                dp.add(dpo);
            else if (dpo.isArray())
                dp = ((PdfArray)dpo).getArrayList();
        }
        for (int j = 0; j < filters.size(); ++j) {
            PdfName filterName = (PdfName)filters.get(j);
            FilterHandlers.FilterHandler filterHandler = filterHandlers.get(filterName);
            if (filterHandler == null)
                throw new UnsupportedPdfException(MessageLocalization.getComposedMessage("the.filter.1.is.not.supported", filterName));
            
            PdfDictionary decodeParams;
            if (j < dp.size()){
                PdfObject dpEntry = getPdfObject(dp.get(j));
                if (dpEntry instanceof PdfDictionary){
                    decodeParams = (PdfDictionary)dpEntry;
                } else if (dpEntry == null || dpEntry instanceof PdfNull ||
                        (dpEntry instanceof PdfLiteral && Arrays.equals("null".getBytes(), ((PdfLiteral)dpEntry).getBytes()))) {
                    decodeParams = null;
                } else {
                    throw new UnsupportedPdfException(MessageLocalization.getComposedMessage("the.decode.parameter.type.1.is.not.supported", dpEntry.getClass().toString()));
                }
                
            } else {
                decodeParams = null;
            }
            b = filterHandler.decode(b, filterName, decodeParams, streamDictionary);
            if (null != memoryLimitsAwareHandler) {
                memoryLimitsAwareHandler.considerBytesOccupiedByDecompressedPdfStream(b.length);
            }
        }
        if (null != memoryLimitsAwareHandler) {
            memoryLimitsAwareHandler.endDecompressedPdfStreamProcessing();
        }
        return b;
    }

    /** Get the content from a stream applying the required filters.
     * @param stream the stream
     * @param file the location where the stream is
     * @throws IOException on error
     * @return the stream content
     */
    public static byte[] getStreamBytes(final PRStream stream, final RandomAccessFileOrArray file) throws IOException {
        byte[] b = getStreamBytesRaw(stream, file);
        return decodeBytes(b, stream);
    }

    /** Get the content from a stream applying the required filters.
     * @param stream the stream
     * @throws IOException on error
     * @return the stream content
     */
    public static byte[] getStreamBytes(final PRStream stream) throws IOException {
        RandomAccessFileOrArray rf = stream.getReader().getSafeFile();
        try {
            rf.reOpen();
            return getStreamBytes(stream, rf);
        }
        finally {
            try{rf.close();}catch(Exception e){}
        }
    }

    /** Get the content from a stream as it is without applying any filter.
     * @param stream the stream
     * @param file the location where the stream is
     * @throws IOException on error
     * @return the stream content
     */
    public static byte[] getStreamBytesRaw(final PRStream stream, final RandomAccessFileOrArray file) throws IOException {
        PdfReader reader = stream.getReader();
        byte b[];
        if (stream.getOffset() < 0)
            b = stream.getBytes();
        else {
            b = new byte[stream.getLength()];
            file.seek(stream.getOffset());
            file.readFully(b);
            PdfEncryption decrypt = reader.getDecrypt();
            if (decrypt != null) {
                PdfObject filter = getPdfObjectRelease(stream.get(PdfName.FILTER));
                ArrayList<PdfObject> filters = new ArrayList<PdfObject>();
                if (filter != null) {
                    if (filter.isName())
                        filters.add(filter);
                    else if (filter.isArray())
                        filters = ((PdfArray)filter).getArrayList();
                }
                boolean skip = false;
                for (int k = 0; k < filters.size(); ++k) {
                    PdfObject obj = getPdfObjectRelease(filters.get(k));
                    if (obj != null && obj.toString().equals("/Crypt")) {
                        skip = true;
                        break;
                    }
                }
                if (!skip) {
                    decrypt.setHashKey(stream.getObjNum(), stream.getObjGen());
                    b = decrypt.decryptByteArray(b);
                }
            }
        }
        return b;
    }

    /** Get the content from a stream as it is without applying any filter.
     * @param stream the stream
     * @throws IOException on error
     * @return the stream content
     */
    public static byte[] getStreamBytesRaw(final PRStream stream) throws IOException {
        RandomAccessFileOrArray rf = stream.getReader().getSafeFile();
        try {
            rf.reOpen();
            return getStreamBytesRaw(stream, rf);
        }
        finally {
            try{rf.close();}catch(Exception e){}
        }
    }

    /** Eliminates shared streams if they exist. */
    public void eliminateSharedStreams() {
        if (!sharedStreams)
            return;
        sharedStreams = false;
        if (pageRefs.size() == 1)
            return;
        ArrayList<PRIndirectReference> newRefs = new ArrayList<PRIndirectReference>();
        ArrayList<PRStream> newStreams = new ArrayList<PRStream>();
        IntHashtable visited = new IntHashtable();
        for (int k = 1; k <= pageRefs.size(); ++k) {
            PdfDictionary page = pageRefs.getPageN(k);
            if (page == null)
                continue;
            PdfObject contents = getPdfObject(page.get(PdfName.CONTENTS));
            if (contents == null)
                continue;
            if (contents.isStream()) {
                PRIndirectReference ref = (PRIndirectReference)page.get(PdfName.CONTENTS);
                if (visited.containsKey(ref.getNumber())) {
                    // need to duplicate
                    newRefs.add(ref);
                    newStreams.add(new PRStream((PRStream)contents, null));
                }
                else
                    visited.put(ref.getNumber(), 1);
            }
            else if (contents.isArray()) {
                PdfArray array = (PdfArray)contents;
                for (int j = 0; j < array.size(); ++j) {
                    PRIndirectReference ref = (PRIndirectReference)array.getPdfObject(j);
                    if (visited.containsKey(ref.getNumber())) {
                        // need to duplicate
                        newRefs.add(ref);
                        newStreams.add(new PRStream((PRStream)getPdfObject(ref), null));
                    }
                    else
                        visited.put(ref.getNumber(), 1);
                }
            }
        }
        if (newStreams.isEmpty())
            return;
        for (int k = 0; k < newStreams.size(); ++k) {
            xrefObj.add(newStreams.get(k));
            PRIndirectReference ref = newRefs.get(k);
            ref.setNumber(xrefObj.size() - 1, 0);
        }
    }

    /** Checks if the document was changed.
     * @return <CODE>true</CODE> if the document was changed,
     * <CODE>false</CODE> otherwise
     */
    public boolean isTampered() {
        return tampered;
    }

    /**
     * Sets the tampered state. A tampered PdfReader cannot be reused in PdfStamper.
     * @param tampered the tampered state
     */
    public void setTampered(final boolean tampered) {
        this.tampered = tampered;
        pageRefs.keepPages();
    }

    /** Gets the XML metadata.
     * @throws IOException on error
     * @return the XML metadata
     */
    public byte[] getMetadata() throws IOException {
        PdfObject obj = getPdfObject(catalog.get(PdfName.METADATA));
        if (!(obj instanceof PRStream))
            return null;
        RandomAccessFileOrArray rf = getSafeFile();
        byte b[] = null;
        try {
            rf.reOpen();
            b = getStreamBytes((PRStream)obj, rf);
        }
        finally {
            try {
                rf.close();
            }
            catch (Exception e) {
                // empty on purpose
            }
        }
        return b;
    }

    /**
     * Gets the byte address of the last xref table.
     * @return the byte address of the last xref table
     */
    public long getLastXref() {
        return lastXref;
    }

    /**
     * Gets the number of xref objects.
     * @return the number of xref objects
     */
    public int getXrefSize() {
        return xrefObj.size();
    }

    /**
     * Gets the byte address of the %%EOF marker.
     * @return the byte address of the %%EOF marker
     */
    public long getEofPos() {
        return eofPos;
    }

    /**
     * Gets the PDF version. Only the last version char is returned. For example
     * version 1.4 is returned as '4'.
     * @return the PDF version
     */
    public char getPdfVersion() {
        return pdfVersion;
    }

    /**
     * Returns <CODE>true</CODE> if the PDF is encrypted.
     * @return <CODE>true</CODE> if the PDF is encrypted
     */
    public boolean isEncrypted() {
        return encrypted;
    }

    /**
     * Gets the encryption permissions. It can be used directly in
     * <CODE>PdfWriter.setEncryption()</CODE>.
     * @return the encryption permissions
     */
    public long getPermissions() {
        return pValue;
    }

    /**
     * Returns <CODE>true</CODE> if the PDF has a 128 bit key encryption.
     * @return <CODE>true</CODE> if the PDF has a 128 bit key encryption
     */
    public boolean is128Key() {
        return rValue == 3;
    }

    /**
     * Gets the trailer dictionary
     * @return the trailer dictionary
     */
    public PdfDictionary getTrailer() {
        return trailer;
    }

    PdfEncryption getDecrypt() {
        return decrypt;
    }

    static boolean equalsn(final byte a1[], final byte a2[]) {
        int length = a2.length;
        for (int k = 0; k < length; ++k) {
            if (a1[k] != a2[k])
                return false;
        }
        return true;
    }

    static boolean existsName(final PdfDictionary dic, final PdfName key, final PdfName value) {
        PdfObject type = getPdfObjectRelease(dic.get(key));
        if (type == null || !type.isName())
            return false;
        PdfName name = (PdfName)type;
        return name.equals(value);
    }

    static String getFontName(final PdfDictionary dic) {
        if (dic == null)
            return null;
        PdfObject type = getPdfObjectRelease(dic.get(PdfName.BASEFONT));
        if (type == null || !type.isName())
            return null;
        return PdfName.decodeName(type.toString());
    }

    static String getSubsetPrefix(final PdfDictionary dic) {
        if (dic == null)
            return null;
        String s = getFontName(dic);
        if (s == null)
            return null;
        if (s.length() < 8 || s.charAt(6) != '+')
            return null;
        for (int k = 0; k < 6; ++k) {
            char c = s.charAt(k);
            if (c < 'A' || c > 'Z')
                return null;
        }
        return s;
    }

    /** Finds all the font subsets and changes the prefixes to some
     * random values.
     * @return the number of font subsets altered
     */
    public int shuffleSubsetNames() {
        int total = 0;
        for (int k = 1; k < xrefObj.size(); ++k) {
            PdfObject obj = getPdfObjectRelease(k);
            if (obj == null || !obj.isDictionary())
                continue;
            PdfDictionary dic = (PdfDictionary)obj;
            if (!existsName(dic, PdfName.TYPE, PdfName.FONT))
                continue;
            if (existsName(dic, PdfName.SUBTYPE, PdfName.TYPE1)
                || existsName(dic, PdfName.SUBTYPE, PdfName.MMTYPE1)
                || existsName(dic, PdfName.SUBTYPE, PdfName.TRUETYPE)) {
                String s = getSubsetPrefix(dic);
                if (s == null)
                    continue;
                String ns = BaseFont.createSubsetPrefix() + s.substring(7);
                PdfName newName = new PdfName(ns);
                dic.put(PdfName.BASEFONT, newName);
                setXrefPartialObject(k, dic);
                ++total;
                PdfDictionary fd = dic.getAsDict(PdfName.FONTDESCRIPTOR);
                if (fd == null)
                    continue;
                fd.put(PdfName.FONTNAME, newName);
            }
            else if (existsName(dic, PdfName.SUBTYPE, PdfName.TYPE0)) {
                String s = getSubsetPrefix(dic);
                PdfArray arr = dic.getAsArray(PdfName.DESCENDANTFONTS);
                if (arr == null)
                    continue;
                if (arr.isEmpty())
                    continue;
                PdfDictionary desc = arr.getAsDict(0);
                String sde = getSubsetPrefix(desc);
                if (sde == null)
                    continue;
                String ns = BaseFont.createSubsetPrefix();
                if (s != null)
                    dic.put(PdfName.BASEFONT, new PdfName(ns + s.substring(7)));
                setXrefPartialObject(k, dic);
                PdfName newName = new PdfName(ns + sde.substring(7));
                desc.put(PdfName.BASEFONT, newName);
                ++total;
                PdfDictionary fd = desc.getAsDict(PdfName.FONTDESCRIPTOR);
                if (fd == null)
                    continue;
                fd.put(PdfName.FONTNAME, newName);
            }
        }
        return total;
    }

    /** Finds all the fonts not subset but embedded and marks them as subset.
     * @return the number of fonts altered
     */
    public int createFakeFontSubsets() {
        int total = 0;
        for (int k = 1; k < xrefObj.size(); ++k) {
            PdfObject obj = getPdfObjectRelease(k);
            if (obj == null || !obj.isDictionary())
                continue;
            PdfDictionary dic = (PdfDictionary)obj;
            if (!existsName(dic, PdfName.TYPE, PdfName.FONT))
                continue;
            if (existsName(dic, PdfName.SUBTYPE, PdfName.TYPE1)
                || existsName(dic, PdfName.SUBTYPE, PdfName.MMTYPE1)
                || existsName(dic, PdfName.SUBTYPE, PdfName.TRUETYPE)) {
                String s = getSubsetPrefix(dic);
                if (s != null)
                    continue;
                s = getFontName(dic);
                if (s == null)
                    continue;
                String ns = BaseFont.createSubsetPrefix() + s;
                PdfDictionary fd = (PdfDictionary)getPdfObjectRelease(dic.get(PdfName.FONTDESCRIPTOR));
                if (fd == null)
                    continue;
                if (fd.get(PdfName.FONTFILE) == null && fd.get(PdfName.FONTFILE2) == null
                    && fd.get(PdfName.FONTFILE3) == null)
                    continue;
                fd = dic.getAsDict(PdfName.FONTDESCRIPTOR);
                PdfName newName = new PdfName(ns);
                dic.put(PdfName.BASEFONT, newName);
                fd.put(PdfName.FONTNAME, newName);
                setXrefPartialObject(k, dic);
                ++total;
            }
        }
        return total;
    }

    private static PdfArray getNameArray(PdfObject obj) {
        if (obj == null)
            return null;
        obj = getPdfObjectRelease(obj);
        if (obj == null)
            return null;
        if (obj.isArray())
            return (PdfArray)obj;
        else if (obj.isDictionary()) {
            PdfObject arr2 = getPdfObjectRelease(((PdfDictionary)obj).get(PdfName.D));
            if (arr2 != null && arr2.isArray())
                return (PdfArray)arr2;
        }
        return null;
    }

    /**
     * Gets all the named destinations as an <CODE>HashMap</CODE>. The key is the name
     * and the value is the destinations array.
     * @return gets all the named destinations
     */
    public HashMap<Object, PdfObject> getNamedDestination() {
    	return getNamedDestination(false);
    }

    /**
     * Gets all the named destinations as an <CODE>HashMap</CODE>. The key is the name
     * and the value is the destinations array.
     * @param	keepNames	true if you want the keys to be real PdfNames instead of Strings
     * @return gets all the named destinations
     * @since	2.1.6
     */
    public HashMap<Object, PdfObject> getNamedDestination(final boolean keepNames) {
        HashMap<Object, PdfObject> names = getNamedDestinationFromNames(keepNames);
        names.putAll(getNamedDestinationFromStrings());
        return names;
    }

    /**
     * Gets the named destinations from the /Dests key in the catalog as an <CODE>HashMap</CODE>. The key is the name
     * and the value is the destinations array.
     * @return gets the named destinations
     * @since 5.0.1 (generic type in signature)
     */
    @SuppressWarnings("unchecked")
    public HashMap<String, PdfObject> getNamedDestinationFromNames() {
    	return new HashMap(getNamedDestinationFromNames(false));
    }

    /**
     * Gets the named destinations from the /Dests key in the catalog as an <CODE>HashMap</CODE>. The key is the name
     * and the value is the destinations array.
     * @param	keepNames	true if you want the keys to be real PdfNames instead of Strings
     * @return gets the named destinations
     * @since	2.1.6
     */
    public HashMap<Object, PdfObject> getNamedDestinationFromNames(final boolean keepNames) {
        HashMap<Object, PdfObject> names = new HashMap<Object, PdfObject>();
        if (catalog.get(PdfName.DESTS) != null) {
            PdfDictionary dic = (PdfDictionary)getPdfObjectRelease(catalog.get(PdfName.DESTS));
            if (dic == null)
                return names;
            Set<PdfName> keys = dic.getKeys();
            for (PdfName key : keys) {
                PdfArray arr = getNameArray(dic.get(key));
                if (arr == null)
                	continue;
                if (keepNames) {
                	names.put(key, arr);
                }
                else {
                	String name = PdfName.decodeName(key.toString());
                	names.put(name, arr);
                }
            }
        }
        return names;
    }

    /**
     * Gets the named destinations from the /Names key in the catalog as an <CODE>HashMap</CODE>. The key is the name
     * and the value is the destinations array.
     * @return gets the named destinations
     */
    public HashMap<String, PdfObject> getNamedDestinationFromStrings() {
        if (catalog.get(PdfName.NAMES) != null) {
            PdfDictionary dic = (PdfDictionary)getPdfObjectRelease(catalog.get(PdfName.NAMES));
            if (dic != null) {
                dic = (PdfDictionary)getPdfObjectRelease(dic.get(PdfName.DESTS));
                if (dic != null) {
                    HashMap<String, PdfObject> names = PdfNameTree.readTree(dic);
                    for (Iterator<Map.Entry<String, PdfObject>> it = names.entrySet().iterator(); it.hasNext();) {
                        Map.Entry<String, PdfObject> entry = it.next();
                        PdfArray arr = getNameArray(entry.getValue());
                        if (arr != null)
                            entry.setValue(arr);
                        else
                            it.remove();
                    }
                    return names;
                }
            }
        }
        return new HashMap<String, PdfObject>();
    }

    /**
     * Removes all the fields from the document.
     */
    public void removeFields() {
        pageRefs.resetReleasePage();
        for (int k = 1; k <= pageRefs.size(); ++k) {
            PdfDictionary page = pageRefs.getPageN(k);
            PdfArray annots = page.getAsArray(PdfName.ANNOTS);
            if (annots == null) {
                pageRefs.releasePage(k);
                continue;
            }
            for (int j = 0; j < annots.size(); ++j) {
                PdfObject obj = getPdfObjectRelease(annots.getPdfObject(j));
                if (obj == null || !obj.isDictionary())
                    continue;
                PdfDictionary annot = (PdfDictionary)obj;
                if (PdfName.WIDGET.equals(annot.get(PdfName.SUBTYPE)))
                    annots.remove(j--);
            }
            if (annots.isEmpty())
                page.remove(PdfName.ANNOTS);
            else
                pageRefs.releasePage(k);
        }
        catalog.remove(PdfName.ACROFORM);
        pageRefs.resetReleasePage();
    }

    /**
     * Removes all the annotations and fields from the document.
     */
    public void removeAnnotations() {
        pageRefs.resetReleasePage();
        for (int k = 1; k <= pageRefs.size(); ++k) {
            PdfDictionary page = pageRefs.getPageN(k);
            if (page.get(PdfName.ANNOTS) == null)
                pageRefs.releasePage(k);
            else
                page.remove(PdfName.ANNOTS);
        }
        catalog.remove(PdfName.ACROFORM);
        pageRefs.resetReleasePage();
    }

    /**
     * Retrieves links for a certain page.
     * @param page the page to inspect
     * @return a list of links
     */
    public ArrayList<PdfAnnotation.PdfImportedLink> getLinks(final int page) {
        pageRefs.resetReleasePage();
        ArrayList<PdfAnnotation.PdfImportedLink> result = new ArrayList<PdfAnnotation.PdfImportedLink>();
        PdfDictionary pageDic = pageRefs.getPageN(page);
        if (pageDic.get(PdfName.ANNOTS) != null) {
            PdfArray annots = pageDic.getAsArray(PdfName.ANNOTS);
            for (int j = 0; j < annots.size(); ++j) {
                PdfDictionary annot = (PdfDictionary)getPdfObjectRelease(annots.getPdfObject(j));

                if (PdfName.LINK.equals(annot.get(PdfName.SUBTYPE))) {
                	result.add(new PdfAnnotation.PdfImportedLink(annot));
                }
            }
        }
    	pageRefs.releasePage(page);
        pageRefs.resetReleasePage();
        return result;
    }

    private void iterateBookmarks(PdfObject outlineRef, final HashMap<Object, PdfObject> names) {
        while (outlineRef != null) {
            replaceNamedDestination(outlineRef, names);
            PdfDictionary outline = (PdfDictionary)getPdfObjectRelease(outlineRef);
            PdfObject first = outline.get(PdfName.FIRST);
            if (first != null) {
                iterateBookmarks(first, names);
            }
            outlineRef = outline.get(PdfName.NEXT);
        }
    }

    /**
     * Replaces remote named links with local destinations that have the same name.
     * @since	5.0
     */
    public void makeRemoteNamedDestinationsLocal() {
        if (remoteToLocalNamedDestinations)
            return;
        remoteToLocalNamedDestinations = true;
        HashMap<Object, PdfObject> names = getNamedDestination(true);
        if (names.isEmpty())
            return;
        for (int k = 1; k <= pageRefs.size(); ++k) {
            PdfDictionary page = pageRefs.getPageN(k);
            PdfObject annotsRef;
            PdfArray annots = (PdfArray)getPdfObject(annotsRef = page.get(PdfName.ANNOTS));
            int annotIdx = lastXrefPartial;
            releaseLastXrefPartial();
            if (annots == null) {
                pageRefs.releasePage(k);
                continue;
            }
            boolean commitAnnots = false;
            for (int an = 0; an < annots.size(); ++an) {
                PdfObject objRef = annots.getPdfObject(an);
                if (convertNamedDestination(objRef, names) && !objRef.isIndirect())
                    commitAnnots = true;
            }
            if (commitAnnots)
                setXrefPartialObject(annotIdx,  annots);
            if (!commitAnnots || annotsRef.isIndirect())
                pageRefs.releasePage(k);
        }
    }

    /**
     * Converts a remote named destination GoToR with a local named destination
     * if there's a corresponding name.
     * @param	obj	an annotation that needs to be screened for links to external named destinations.
     * @param	names	a map with names of local named destinations
     * @since	iText 5.0
     */
    private boolean convertNamedDestination(PdfObject obj, final HashMap<Object, PdfObject> names) {
        obj = getPdfObject(obj);
        int objIdx = lastXrefPartial;
        releaseLastXrefPartial();
        if (obj != null && obj.isDictionary()) {
            PdfObject ob2 = getPdfObject(((PdfDictionary)obj).get(PdfName.A));
            if (ob2 != null) {
                int obj2Idx = lastXrefPartial;
                releaseLastXrefPartial();
                PdfDictionary dic = (PdfDictionary)ob2;
                PdfName type = (PdfName)getPdfObjectRelease(dic.get(PdfName.S));
                if (PdfName.GOTOR.equals(type)) {
                    PdfObject ob3 = getPdfObjectRelease(dic.get(PdfName.D));
                    Object name = null;
                    if (ob3 != null) {
                        if (ob3.isName())
                            name = ob3;
                        else if (ob3.isString())
                            name = ob3.toString();
                        PdfArray dest = (PdfArray)names.get(name);
                        if (dest != null) {
                        	dic.remove(PdfName.F);
                        	dic.remove(PdfName.NEWWINDOW);
                        	dic.put(PdfName.S, PdfName.GOTO);
                        	setXrefPartialObject(obj2Idx, ob2);
                        	setXrefPartialObject(objIdx, obj);
                        	return true;
                        }
                    }
                }
            }
        }
        return false;
    }

    /** Replaces all the local named links with the actual destinations. */
    public void consolidateNamedDestinations() {
        if (consolidateNamedDestinations)
            return;
        consolidateNamedDestinations = true;
        HashMap<Object, PdfObject> names = getNamedDestination(true);
        if (names.isEmpty())
            return;
        for (int k = 1; k <= pageRefs.size(); ++k) {
            PdfDictionary page = pageRefs.getPageN(k);
            PdfObject annotsRef;
            PdfArray annots = (PdfArray)getPdfObject(annotsRef = page.get(PdfName.ANNOTS));
            int annotIdx = lastXrefPartial;
            releaseLastXrefPartial();
            if (annots == null) {
                pageRefs.releasePage(k);
                continue;
            }
            boolean commitAnnots = false;
            for (int an = 0; an < annots.size(); ++an) {
                PdfObject objRef = annots.getPdfObject(an);
                if (replaceNamedDestination(objRef, names) && !objRef.isIndirect())
                    commitAnnots = true;
            }
            if (commitAnnots)
                setXrefPartialObject(annotIdx,  annots);
            if (!commitAnnots || annotsRef.isIndirect())
                pageRefs.releasePage(k);
        }
        PdfDictionary outlines = (PdfDictionary)getPdfObjectRelease(catalog.get(PdfName.OUTLINES));
        if (outlines == null)
            return;
        iterateBookmarks(outlines.get(PdfName.FIRST), names);
    }

    private boolean replaceNamedDestination(PdfObject obj, final HashMap<Object, PdfObject> names) {
        obj = getPdfObject(obj);
        int objIdx = lastXrefPartial;
        releaseLastXrefPartial();
        if (obj != null && obj.isDictionary()) {
            PdfObject ob2 = getPdfObjectRelease(((PdfDictionary)obj).get(PdfName.DEST));
            Object name = null;
            if (ob2 != null) {
                if (ob2.isName())
                    name = ob2;
                else if (ob2.isString())
                    name = ob2.toString();
                PdfArray dest = (PdfArray)names.get(name);
                if (dest != null) {
                    ((PdfDictionary)obj).put(PdfName.DEST, dest);
                    setXrefPartialObject(objIdx, obj);
                    return true;
                }
            }
            else if ((ob2 = getPdfObject(((PdfDictionary)obj).get(PdfName.A))) != null) {
                int obj2Idx = lastXrefPartial;
                releaseLastXrefPartial();
                PdfDictionary dic = (PdfDictionary)ob2;
                PdfName type = (PdfName)getPdfObjectRelease(dic.get(PdfName.S));
                if (PdfName.GOTO.equals(type)) {
                    PdfObject ob3 = getPdfObjectRelease(dic.get(PdfName.D));
                    if (ob3 != null) {
                        if (ob3.isName())
                            name = ob3;
                        else if (ob3.isString())
                            name = ob3.toString();
                    }
                    PdfArray dest = (PdfArray)names.get(name);
                    if (dest != null) {
                        dic.put(PdfName.D, dest);
                        setXrefPartialObject(obj2Idx, ob2);
                        setXrefPartialObject(objIdx, obj);
                        return true;
                    }
                }
            }
        }
        return false;
    }

    protected static PdfDictionary duplicatePdfDictionary(final PdfDictionary original, PdfDictionary copy, final PdfReader newReader) {
        if (copy == null)
            copy = new PdfDictionary(original.size());
        for (Object element : original.getKeys()) {
            PdfName key = (PdfName)element;
            copy.put(key, duplicatePdfObject(original.get(key), newReader));
        }
        return copy;
    }

    protected static PdfObject duplicatePdfObject(final PdfObject original, final PdfReader newReader) {
        if (original == null)
            return null;
        switch (original.type()) {
            case PdfObject.DICTIONARY: {
                return duplicatePdfDictionary((PdfDictionary)original, null, newReader);
            }
            case PdfObject.STREAM: {
                PRStream org = (PRStream)original;
                PRStream stream = new PRStream(org, null, newReader);
                duplicatePdfDictionary(org, stream, newReader);
                return stream;
            }
            case PdfObject.ARRAY: {
                PdfArray originalArray = (PdfArray) original;
                PdfArray arr = new PdfArray(originalArray.size());
                for (Iterator<PdfObject> it = originalArray.listIterator(); it.hasNext();) {
                    arr.add(duplicatePdfObject(it.next(), newReader));
                }
                return arr;
            }
            case PdfObject.INDIRECT: {
                PRIndirectReference org = (PRIndirectReference)original;
                return new PRIndirectReference(newReader, org.getNumber(), org.getGeneration());
            }
            default:
                return original;
        }
    }

    /**
     * Closes the reader, and any underlying stream or data source used to create the reader
     */
    public void close() {
        try {
            tokens.close();
        }
        catch (IOException e) {
            throw new ExceptionConverter(e);
        }
    }

    @SuppressWarnings("unchecked")
    protected void removeUnusedNode(PdfObject obj, final boolean hits[]) {
        Stack<Object> state = new Stack<Object>();
        state.push(obj);
        while (!state.empty()) {
            Object current = state.pop();
            if (current == null)
                continue;
            ArrayList<PdfObject> ar = null;
            PdfDictionary dic = null;
            PdfName[] keys = null;
            Object[] objs = null;
            int idx = 0;
            if (current instanceof PdfObject) {
                obj = (PdfObject)current;
                switch (obj.type()) {
                    case PdfObject.DICTIONARY:
                    case PdfObject.STREAM:
                        dic = (PdfDictionary)obj;
                        keys = new PdfName[dic.size()];
                        dic.getKeys().toArray(keys);
                        break;
                    case PdfObject.ARRAY:
                         ar = ((PdfArray)obj).getArrayList();
                         break;
                    case PdfObject.INDIRECT:
                        PRIndirectReference ref = (PRIndirectReference)obj;
                        int num = ref.getNumber();
                        if (!hits[num]) {
                            hits[num] = true;
                            state.push(getPdfObjectRelease(ref));
                        }
                        continue;
                    default:
                        continue;
                }
            }
            else {
                objs = (Object[])current;
                if (objs[0] instanceof ArrayList) {
                    ar = (ArrayList<PdfObject>)objs[0];
                    idx = ((Integer)objs[1]).intValue();
                }
                else {
                    keys = (PdfName[])objs[0];
                    dic = (PdfDictionary)objs[1];
                    idx = ((Integer)objs[2]).intValue();
                }
            }
            if (ar != null) {
                for (int k = idx; k < ar.size(); ++k) {
                    PdfObject v = ar.get(k);
                    if (v.isIndirect()) {
                        int num = ((PRIndirectReference)v).getNumber();
                        if (num >= xrefObj.size() || !partial && xrefObj.get(num) == null) {
                            ar.set(k, PdfNull.PDFNULL);
                            continue;
                        }
                    }
                    if (objs == null)
                        state.push(new Object[]{ar, Integer.valueOf(k + 1)});
                    else {
                        objs[1] = Integer.valueOf(k + 1);
                        state.push(objs);
                    }
                    state.push(v);
                    break;
                }
            }
            else {
                for (int k = idx; k < keys.length; ++k) {
                    PdfName key = keys[k];
                    PdfObject v = dic.get(key);
                    if (v.isIndirect()) {
                        int num = ((PRIndirectReference)v).getNumber();
                        if (num < 0 || num >= xrefObj.size() || !partial && xrefObj.get(num) == null) {
                            dic.put(key, PdfNull.PDFNULL);
                            continue;
                        }
                    }
                    if (objs == null)
                        state.push(new Object[]{keys, dic, Integer.valueOf(k + 1)});
                    else {
                        objs[2] = Integer.valueOf(k + 1);
                        state.push(objs);
                    }
                    state.push(v);
                    break;
                }
            }
        }
    }

    /**
     * Removes all the unreachable objects.
     * @return the number of indirect objects removed
     */
    public int removeUnusedObjects() {
        boolean hits[] = new boolean[xrefObj.size()];
        removeUnusedNode(trailer, hits);
        int total = 0;
        if (partial) {
            for (int k = 1; k < hits.length; ++k) {
                if (!hits[k]) {
                    xref[k * 2] = -1;
                    xref[k * 2 + 1] = 0;
                    xrefObj.set(k, null);
                    ++total;
                }
            }
        }
        else {
            for (int k = 1; k < hits.length; ++k) {
                if (!hits[k]) {
                    xrefObj.set(k, null);
                    ++total;
                }
            }
        }
        return total;
    }

    /** Gets a read-only version of <CODE>AcroFields</CODE>.
     * @return a read-only version of <CODE>AcroFields</CODE>
     */
    public AcroFields getAcroFields() {
        return new AcroFields(this, null);
    }

    /**
     * Gets the global document JavaScript.
     * @param file the document file
     * @throws IOException on error
     * @return the global document JavaScript
     */
    public String getJavaScript(final RandomAccessFileOrArray file) throws IOException {
        PdfDictionary names = (PdfDictionary)getPdfObjectRelease(catalog.get(PdfName.NAMES));
        if (names == null)
            return null;
        PdfDictionary js = (PdfDictionary)getPdfObjectRelease(names.get(PdfName.JAVASCRIPT));
        if (js == null)
            return null;
        HashMap<String, PdfObject> jscript = PdfNameTree.readTree(js);
        String sortedNames[] = new String[jscript.size()];
        sortedNames = jscript.keySet().toArray(sortedNames);
        Arrays.sort(sortedNames);
        StringBuffer buf = new StringBuffer();
        for (int k = 0; k < sortedNames.length; ++k) {
            PdfDictionary j = (PdfDictionary)getPdfObjectRelease(jscript.get(sortedNames[k]));
            if (j == null)
                continue;
            PdfObject obj = getPdfObjectRelease(j.get(PdfName.JS));
            if (obj != null) {
                if (obj.isString())
                    buf.append(((PdfString)obj).toUnicodeString()).append('\n');
                else if (obj.isStream()) {
                    byte bytes[] = getStreamBytes((PRStream)obj, file);
                    if (bytes.length >= 2 && bytes[0] == (byte)254 && bytes[1] == (byte)255)
                        buf.append(PdfEncodings.convertToString(bytes, PdfObject.TEXT_UNICODE));
                    else
                        buf.append(PdfEncodings.convertToString(bytes, PdfObject.TEXT_PDFDOCENCODING));
                    buf.append('\n');
                }
            }
        }
        return buf.toString();
    }

    /**
     * Gets the global document JavaScript.
     * @throws IOException on error
     * @return the global document JavaScript
     */
    public String getJavaScript() throws IOException {
        RandomAccessFileOrArray rf = getSafeFile();
        try {
            rf.reOpen();
            return getJavaScript(rf);
        }
        finally {
            try{rf.close();}catch(Exception e){}
        }
    }

    /**
     * Selects the pages to keep in the document. The pages are described as
     * ranges. The page ordering can be changed but
     * no page repetitions are allowed. Note that it may be very slow in partial mode.
     * @param ranges the comma separated ranges as described in {@link SequenceList}
     */
    public void selectPages(final String ranges) {
        selectPages(SequenceList.expand(ranges, getNumberOfPages()));
    }

    /**
     * Selects the pages to keep in the document. The pages are described as a
     * <CODE>List</CODE> of <CODE>Integer</CODE>. The page ordering can be changed but
     * no page repetitions are allowed. Note that it may be very slow in partial mode.
     * @param pagesToKeep the pages to keep in the document
     */
    public void selectPages(final List<Integer> pagesToKeep) {
        selectPages(pagesToKeep, true);
    }

    /**
     * Selects the pages to keep in the document. The pages are described as a
     * <CODE>List</CODE> of <CODE>Integer</CODE>. The page ordering can be changed but
     * no page repetitions are allowed. Note that it may be very slow in partial mode.
     * @param pagesToKeep the pages to keep in the document
     * @param removeUnused indicate if to remove unsed objects. @see removeUnusedObjects
     */
    protected void selectPages(final List<Integer> pagesToKeep, boolean removeUnused) {
        pageRefs.selectPages(pagesToKeep);
        if (removeUnused) removeUnusedObjects();
    }

    /** Sets the viewer preferences as the sum of several constants.
     * @param preferences the viewer preferences
     * @see PdfViewerPreferences#setViewerPreferences
     */
    public void setViewerPreferences(final int preferences) {
    	this.viewerPreferences.setViewerPreferences(preferences);
        setViewerPreferences(this.viewerPreferences);
    }

    /** Adds a viewer preference
     * @param key a key for a viewer preference
     * @param value	a value for the viewer preference
     * @see PdfViewerPreferences#addViewerPreference
     */
    public void addViewerPreference(final PdfName key, final PdfObject value) {
    	this.viewerPreferences.addViewerPreference(key, value);
        setViewerPreferences(this.viewerPreferences);
    }

    public void setViewerPreferences(final PdfViewerPreferencesImp vp) {
    	vp.addToCatalog(catalog);
    }

    /**
     * Returns a bitset representing the PageMode and PageLayout viewer preferences.
     * Doesn't return any information about the ViewerPreferences dictionary.
     * @return an int that contains the Viewer Preferences.
     */
    public int getSimpleViewerPreferences() {
    	return PdfViewerPreferencesImp.getViewerPreferences(catalog).getPageLayoutAndMode();
    }

    /**
     * Getter for property appendable.
     * @return Value of property appendable.
     */
    public boolean isAppendable() {
        return this.appendable;
    }

    /**
     * Setter for property appendable.
     * @param appendable New value of property appendable.
     */
    public void setAppendable(final boolean appendable) {
        this.appendable = appendable;
        if (appendable)
            getPdfObject(trailer.get(PdfName.ROOT));
    }

    /**
     * Getter for property newXrefType.
     * @return Value of property newXrefType.
     */
    public boolean isNewXrefType() {
        return newXrefType;
    }

    /**
     * Getter for property fileLength.
     * @return Value of property fileLength.
     */
    public long getFileLength() {
        return fileLength;
    }

    /**
     * Getter for property hybridXref.
     * @return Value of property hybridXref.
     */
    public boolean isHybridXref() {
        return hybridXref;
    }

    static class PageRefs {
        private final PdfReader reader;
        /** ArrayList with the indirect references to every page. Element 0 = page 1; 1 = page 2;... Not used for partial reading. */
        private ArrayList<PRIndirectReference> refsn;
        /** The number of pages, updated only in case of partial reading. */
        private int sizep;
        /** intHashtable that does the same thing as refsn in case of partial reading: major difference: not all the pages are read. */
        private IntHashtable refsp;
        /** Page number of the last page that was read (partial reading only) */
        private int lastPageRead = -1;
        /** stack to which pages dictionaries are pushed to keep track of the current page attributes */
        private ArrayList<PdfDictionary> pageInh;
        private boolean keepPages;
        /**
         * Keeps track of all pages nodes to avoid circular references.
         */
        private Set<PdfObject> pagesNodes = new HashSet<PdfObject>();

        private PageRefs(final PdfReader reader) throws IOException {
            this.reader = reader;
            if (reader.partial) {
                refsp = new IntHashtable();
                PdfNumber npages = (PdfNumber)PdfReader.getPdfObjectRelease(reader.rootPages.get(PdfName.COUNT));
                sizep = npages.intValue();
            }
            else {
                readPages();
            }
        }

        PageRefs(final PageRefs other, final PdfReader reader) {
            this.reader = reader;
            this.sizep = other.sizep;
            if (other.refsn != null) {
                refsn = new ArrayList<PRIndirectReference>(other.refsn);
                for (int k = 0; k < refsn.size(); ++k) {
                    refsn.set(k, (PRIndirectReference)duplicatePdfObject(refsn.get(k), reader));
                }
            }
            else
                this.refsp = (IntHashtable)other.refsp.clone();
        }

        int size() {
            if (refsn != null)
                return refsn.size();
            else
                return sizep;
        }

        void readPages() throws IOException {
            if (refsn != null)
                return;
            refsp = null;
            refsn = new ArrayList<PRIndirectReference>();
            pageInh = new ArrayList<PdfDictionary>();
            iteratePages((PRIndirectReference)reader.catalog.get(PdfName.PAGES));
            pageInh = null;
            reader.rootPages.put(PdfName.COUNT, new PdfNumber(refsn.size()));
        }

        void reReadPages() throws IOException {
            refsn = null;
            readPages();
        }

        /** Gets the dictionary that represents a page.
         * @param pageNum the page number. 1 is the first
         * @return the page dictionary
         */
        public PdfDictionary getPageN(final int pageNum) {
            PRIndirectReference ref = getPageOrigRef(pageNum);
            return (PdfDictionary)PdfReader.getPdfObject(ref);
        }

        /**
         * @param pageNum
         * @return a dictionary object
         */
        public PdfDictionary getPageNRelease(final int pageNum) {
            PdfDictionary page = getPageN(pageNum);
            releasePage(pageNum);
            return page;
        }

        /**
         * @param pageNum
         * @return an indirect reference
         */
        public PRIndirectReference getPageOrigRefRelease(final int pageNum) {
            PRIndirectReference ref = getPageOrigRef(pageNum);
            releasePage(pageNum);
            return ref;
        }

        /**
         * Gets the page reference to this page.
         * @param pageNum the page number. 1 is the first
         * @return the page reference
         */
        public PRIndirectReference getPageOrigRef(int pageNum) {
            try {
                --pageNum;
                if (pageNum < 0 || pageNum >= size())
                    return null;
                if (refsn != null)
                    return refsn.get(pageNum);
                else {
                    int n = refsp.get(pageNum);
                    if (n == 0) {
                        PRIndirectReference ref = getSinglePage(pageNum);
                        if (reader.lastXrefPartial == -1)
                            lastPageRead = -1;
                        else
                            lastPageRead = pageNum;
                        reader.lastXrefPartial = -1;
                        refsp.put(pageNum, ref.getNumber());
                        if (keepPages)
                            lastPageRead = -1;
                        return ref;
                    }
                    else {
                        if (lastPageRead != pageNum)
                            lastPageRead = -1;
                        if (keepPages)
                            lastPageRead = -1;
                        return new PRIndirectReference(reader, n);
                    }
                }
            }
            catch (Exception e) {
                throw new ExceptionConverter(e);
            }
        }

        void keepPages() {
            if (refsp == null || keepPages)
                return;
            keepPages = true;
            refsp.clear();
        }

        /**
         * @param pageNum
         */
        public void releasePage(int pageNum) {
            if (refsp == null)
                return;
            --pageNum;
            if (pageNum < 0 || pageNum >= size())
                return;
            if (pageNum != lastPageRead)
                return;
            lastPageRead = -1;
            reader.lastXrefPartial = refsp.get(pageNum);
            reader.releaseLastXrefPartial();
            refsp.remove(pageNum);
        }

        /**
         *
         */
        public void resetReleasePage() {
            if (refsp == null)
                return;
            lastPageRead = -1;
        }

        void insertPage(int pageNum, final PRIndirectReference ref) {
            --pageNum;
            if (refsn != null) {
                if (pageNum >= refsn.size())
                    refsn.add(ref);
                else
                    refsn.add(pageNum, ref);
            }
            else {
                ++sizep;
                lastPageRead = -1;
                if (pageNum >= size()) {
                    refsp.put(size(), ref.getNumber());
                }
                else {
                    IntHashtable refs2 = new IntHashtable((refsp.size() + 1) * 2);
                    for (Iterator<IntHashtable.Entry> it = refsp.getEntryIterator(); it.hasNext();) {
                        IntHashtable.Entry entry = it.next();
                        int p = entry.getKey();
                        refs2.put(p >= pageNum ? p + 1 : p, entry.getValue());
                    }
                    refs2.put(pageNum, ref.getNumber());
                    refsp = refs2;
                }
            }
        }

        /**
         * Adds a PdfDictionary to the pageInh stack to keep track of the page attributes.
         * @param nodePages	a Pages dictionary
         */
        private void pushPageAttributes(final PdfDictionary nodePages) {
            PdfDictionary dic = new PdfDictionary();
            if (!pageInh.isEmpty()) {
                dic.putAll(pageInh.get(pageInh.size() - 1));
            }
            for (int k = 0; k < pageInhCandidates.length; ++k) {
                PdfObject obj = nodePages.get(pageInhCandidates[k]);
                if (obj != null)
                    dic.put(pageInhCandidates[k], obj);
            }
            pageInh.add(dic);
        }

        /**
         * Removes the last PdfDictionary that was pushed to the pageInh stack.
         */
        private void popPageAttributes() {
            pageInh.remove(pageInh.size() - 1);
        }

        private void iteratePages(final PRIndirectReference rpage) throws IOException {
            PdfDictionary page = (PdfDictionary)getPdfObject(rpage);
            if (page == null)
                return;
            if (!pagesNodes.add(getPdfObject(rpage)))
                throw new InvalidPdfException(MessageLocalization.getComposedMessage("illegal.pages.tree"));
            PdfArray kidsPR = page.getAsArray(PdfName.KIDS);
            // reference to a leaf
            if (kidsPR == null) {
                page.put(PdfName.TYPE, PdfName.PAGE);
                PdfDictionary dic = pageInh.get(pageInh.size() - 1);
                PdfName key;
                for (Object element : dic.getKeys()) {
                    key = (PdfName) element;
                    if (page.get(key) == null)
                        page.put(key, dic.get(key));
                }
                if (page.get(PdfName.MEDIABOX) == null) {
                    PdfArray arr = new PdfArray(new float[]{0,0,PageSize.LETTER.getRight(),PageSize.LETTER.getTop()});
                    page.put(PdfName.MEDIABOX, arr);
                }
                refsn.add(rpage);
            }
            // reference to a branch
            else {
                page.put(PdfName.TYPE, PdfName.PAGES);
                pushPageAttributes(page);
                for (int k = 0; k < kidsPR.size(); ++k){
                    PdfObject obj = kidsPR.getPdfObject(k);
                    if (!obj.isIndirect()) {
                        while (k < kidsPR.size())
                            kidsPR.remove(k);
                        break;
                    }
                    iteratePages((PRIndirectReference)obj);
                }
                popPageAttributes();
            }
        }

        protected PRIndirectReference getSinglePage(final int n) {
            PdfDictionary acc = new PdfDictionary();
            PdfDictionary top = reader.rootPages;
            int base = 0;
            while (true) {
                for (int k = 0; k < pageInhCandidates.length; ++k) {
                    PdfObject obj = top.get(pageInhCandidates[k]);
                    if (obj != null)
                        acc.put(pageInhCandidates[k], obj);
                }
                PdfArray kids = (PdfArray)PdfReader.getPdfObjectRelease(top.get(PdfName.KIDS));
                for (Iterator<PdfObject> it = kids.listIterator(); it.hasNext();) {
                    PRIndirectReference ref = (PRIndirectReference)it.next();
                    PdfDictionary dic = (PdfDictionary)getPdfObject(ref);
                    int last = reader.lastXrefPartial;
                    PdfObject count = getPdfObjectRelease(dic.get(PdfName.COUNT));
                    reader.lastXrefPartial = last;
                    int acn = 1;
                    if (count != null && count.type() == PdfObject.NUMBER)
                        acn = ((PdfNumber)count).intValue();
                    if (n < base + acn) {
                        if (count == null) {
                            dic.mergeDifferent(acc);
                            return ref;
                        }
                        reader.releaseLastXrefPartial();
                        top = dic;
                        break;
                    }
                    reader.releaseLastXrefPartial();
                    base += acn;
                }
            }
        }

        private void selectPages(final List<Integer> pagesToKeep) {
            IntHashtable pg = new IntHashtable();
            ArrayList<Integer> finalPages = new ArrayList<Integer>();
            int psize = size();
            for (Integer pi : pagesToKeep) {
                int p = pi.intValue();
                if (p >= 1 && p <= psize && pg.put(p, 1) == 0)
                    finalPages.add(pi);
            }
            if (reader.partial) {
                for (int k = 1; k <= psize; ++k) {
                    getPageOrigRef(k);
                    resetReleasePage();
                }
            }
            PRIndirectReference parent = (PRIndirectReference)reader.catalog.get(PdfName.PAGES);
            PdfDictionary topPages = (PdfDictionary)PdfReader.getPdfObject(parent);
            ArrayList<PRIndirectReference> newPageRefs = new ArrayList<PRIndirectReference>(finalPages.size());
            PdfArray kids = new PdfArray();
            for (int k = 0; k < finalPages.size(); ++k) {
                int p = finalPages.get(k).intValue();
                PRIndirectReference pref = getPageOrigRef(p);
                resetReleasePage();
                kids.add(pref);
                newPageRefs.add(pref);
                getPageN(p).put(PdfName.PARENT, parent);
            }
            AcroFields af = reader.getAcroFields();
            boolean removeFields = af.getFields().size() > 0;
            for (int k = 1; k <= psize; ++k) {
                if (!pg.containsKey(k)) {
                    if (removeFields)
                        af.removeFieldsFromPage(k);
                    PRIndirectReference pref = getPageOrigRef(k);
                    int nref = pref.getNumber();
                    reader.xrefObj.set(nref, null);
                    if (reader.partial) {
                        reader.xref[nref * 2] = -1;
                        reader.xref[nref * 2 + 1] = 0;
                    }
                }
            }
            topPages.put(PdfName.COUNT, new PdfNumber(finalPages.size()));
            topPages.put(PdfName.KIDS, kids);
            refsp = null;
            refsn = newPageRefs;
        }
    }

    PdfIndirectReference getCryptoRef() {
        if (cryptoRef == null)
            return null;
        return new PdfIndirectReference(0, cryptoRef.getNumber(), cryptoRef.getGeneration());
    }
    
    /**
     * Checks if this PDF has usage rights enabled.
     * 
     * @return <code>true</code> if usage rights are present; <code>false</code> otherwise
     */
    public boolean hasUsageRights() {
        PdfDictionary perms = catalog.getAsDict(PdfName.PERMS);
        if (perms == null)
            return false;
        return perms.contains(PdfName.UR) || perms.contains(PdfName.UR3);
    }

    /**
     * Removes any usage rights that this PDF may have. Only Adobe can grant usage rights
     * and any PDF modification with iText will invalidate them. Invalidated usage rights may
     * confuse Acrobat and it's advisable to remove them altogether.
     */
    public void removeUsageRights() {
        PdfDictionary perms = catalog.getAsDict(PdfName.PERMS);
        if (perms == null)
            return;
        perms.remove(PdfName.UR);
        perms.remove(PdfName.UR3);
        if (perms.size() == 0)
            catalog.remove(PdfName.PERMS);
    }

    /**
     * Gets the certification level for this document. The return values can be <code>PdfSignatureAppearance.NOT_CERTIFIED</code>,
     * <code>PdfSignatureAppearance.CERTIFIED_NO_CHANGES_ALLOWED</code>,
     * <code>PdfSignatureAppearance.CERTIFIED_FORM_FILLING</code> and
     * <code>PdfSignatureAppearance.CERTIFIED_FORM_FILLING_AND_ANNOTATIONS</code>.
     * <p>
     * No signature validation is made, use the methods available for that in <CODE>AcroFields</CODE>.
     * </p>
     * @return gets the certification level for this document
     */
    public int getCertificationLevel() {
        PdfDictionary dic = catalog.getAsDict(PdfName.PERMS);
        if (dic == null)
            return PdfSignatureAppearance.NOT_CERTIFIED;
        dic = dic.getAsDict(PdfName.DOCMDP);
        if (dic == null)
            return PdfSignatureAppearance.NOT_CERTIFIED;
        PdfArray arr = dic.getAsArray(PdfName.REFERENCE);
        if (arr == null || arr.size() == 0)
            return PdfSignatureAppearance.NOT_CERTIFIED;
        dic = arr.getAsDict(0);
        if (dic == null)
            return PdfSignatureAppearance.NOT_CERTIFIED;
        dic = dic.getAsDict(PdfName.TRANSFORMPARAMS);
        if (dic == null)
            return PdfSignatureAppearance.NOT_CERTIFIED;
        PdfNumber p = dic.getAsNumber(PdfName.P);
        if (p == null)
            return PdfSignatureAppearance.NOT_CERTIFIED;
        return p.intValue();
    }

    /**
     * Checks if the document was opened with the owner password so that the end application
     * can decide what level of access restrictions to apply. If the document is not encrypted
     * it will return <CODE>true</CODE>.
     * @return <CODE>true</CODE> if the document was opened with the owner password or if it's not encrypted,
     * <CODE>false</CODE> if the document was opened with the user password
     */
    public final boolean isOpenedWithFullPermissions() {
        return !encrypted || ownerPasswordUsed || unethicalreading;
    }

    /**
     * @return the crypto mode, or -1 of none
     */
    public int getCryptoMode() {
    	if (decrypt == null)
    		return -1;
    	else
    		return decrypt.getCryptoMode();
    }

    /**
     * @return true if the metadata is encrypted.
     */
    public boolean isMetadataEncrypted() {
    	if (decrypt == null)
    		return false;
    	else
    		return decrypt.isMetadataEncrypted();
    }

    /**
     * Computes user password if standard encryption handler is used with Standard40, Standard128 or AES128 encryption algorithm.
     *
     * @return user password, or null if not a standard encryption handler was used,
     *         if standard encryption handler was used with AES256 encryption algorithm,
     *         or if ownerPasswordUsed wasn't use to open the document.
     */
    public byte[] computeUserPassword() {
    	if (!encrypted || !ownerPasswordUsed) return null;
    	return decrypt.computeUserPassword(password);
    }
}
