/*
 * $Id: PdfReader.java,v 1.102 2007/04/11 10:30:47 blowagie Exp $
 * $Name:  $
 *
 * Copyright 2001, 2002 Paulo Soares
 *
 * The contents of this file are subject to the Mozilla Public License Version 1.1
 * (the "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the License.
 *
 * The Original Code is 'iText, a free JAVA-PDF library'.
 *
 * The Initial Developer of the Original Code is Bruno Lowagie. Portions created by
 * the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie.
 * All Rights Reserved.
 * Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer
 * are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved.
 *
 * Contributor(s): all the names of the contributors are added in the source code
 * where applicable.
 *
 * Alternatively, the contents of this file may be used under the terms of the
 * LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the
 * provisions of LGPL are applicable instead of those above.  If you wish to
 * allow use of your version of this file only under the terms of the LGPL
 * License and not to allow others to use your version of this file under
 * the MPL, indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by the LGPL.
 * If you do not delete the provisions above, a recipient may use your version
 * of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE.
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the MPL as stated above or under the terms of the GNU
 * Library General Public License as published by the Free Software Foundation;
 * either version 2 of the License, or any later version.
 *
 * This library 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 Library general Public License for more
 * details.
 *
 * If you didn't download this code from the following link, you should check if
 * you aren't using an obsolete version:
 * http://www.lowagie.com/iText/
 */

package com.lowagie.text.pdf;

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.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.zip.InflaterInputStream;
import java.util.Stack;
import java.security.Key;
import java.security.MessageDigest;
import java.security.cert.Certificate;

import com.lowagie.text.ExceptionConverter;
import com.lowagie.text.PageSize;
import com.lowagie.text.Rectangle;
import com.lowagie.text.pdf.interfaces.PdfViewerPreferences;
import com.lowagie.text.pdf.internal.PdfViewerPreferencesImp;

import org.bouncycastle.cms.CMSEnvelopedData;
import org.bouncycastle.cms.RecipientInformation;

/** Reads a PDF document.
 * @author Paulo Soares (psoares@consiste.pt)
 * @author Kazuya Ujihara
 */
public class PdfReader implements PdfViewerPreferences {

    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 int xref[];
    protected HashMap objStmMark;
    protected IntHashtable objStmToOffset;
    protected boolean newXrefType;
    private ArrayList xrefObj;
    PdfDictionary rootPages;
    protected PdfDictionary trailer;
    protected PdfDictionary catalog;
    protected PageRefs pageRefs;
    protected PRAcroForm acroForm = null;
    protected boolean acroFormParsed = false;
    protected ArrayList pageInh;
    protected boolean encrypted = false;
    protected boolean rebuilt = false;
    protected int freeXref;
    protected boolean tampered = false;
    protected int lastXref;
    protected int 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 boolean ownerPasswordUsed;
    protected ArrayList strings = new ArrayList();
    protected boolean sharedStreams = true;
    protected boolean consolidateNamedDestinations = false;
    protected int rValue;
    protected int pValue;
    private int objNum;
    private int objGen;
    private int fileLength;
    private boolean hybridXref;
    private int lastXrefPartial = -1;
    private boolean partial;
    private PRIndirectReference cryptoRef;
	private PdfViewerPreferencesImp viewerPreferences = new PdfViewerPreferencesImp();

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

    protected PdfReader() {
    }

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

    /** 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(String filename, byte ownerPassword[]) throws IOException {
        password = ownerPassword;
        tokens = new PRTokeniser(filename);
        readPdf();
    }

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

    /** 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(byte pdfIn[], byte ownerPassword[]) throws IOException {
        password = ownerPassword;
        tokens = new PRTokeniser(pdfIn);
        readPdf();
    }

    /** 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(String filename, Certificate certificate, Key certificateKey, String certificateKeyProvider) throws IOException {
        this.certificate = certificate;
        this.certificateKey = certificateKey;
        this.certificateKeyProvider = certificateKeyProvider;
        tokens = new PRTokeniser(filename);
        readPdf();
    }        

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

    /** 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(URL url, byte ownerPassword[]) throws IOException {
        password = ownerPassword;
        tokens = new PRTokeniser(new RandomAccessFileOrArray(url));
        readPdf();
    }

    /**
     * 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(InputStream is, byte ownerPassword[]) throws IOException {
        password = ownerPassword;
        tokens = new PRTokeniser(new RandomAccessFileOrArray(is));
        readPdf();
    }

    /**
     * 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(InputStream is) throws IOException {
        this(is, null);
    }

    /**
     * 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. The pdf is left open but may be closed at any time with
     * <CODE>PdfReader.close()</CODE>, reopen is automatic.
     * @param raf the document location
     * @param ownerPassword the password or <CODE>null</CODE> for no password
     * @throws IOException on error
     */
    public PdfReader(RandomAccessFileOrArray raf, byte ownerPassword[]) throws IOException {
        password = ownerPassword;
        partial = true;
        tokens = new PRTokeniser(raf);
        readPdfPartial();
    }

    /** Creates an independent duplicate.
     * @param reader the <CODE>PdfReader</CODE> to duplicate
     */
    public PdfReader(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.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(reader.xrefObj);
        for (int k = 0; k < reader.xrefObj.size(); ++k) {
            this.xrefObj.set(k, duplicatePdfObject((PdfObject)reader.xrefObj.get(k), this));
        }
        this.pageRefs = new PageRefs(reader.pageRefs, this);
        this.trailer = (PdfDictionary)duplicatePdfObject(reader.trailer, this);
        this.catalog = (PdfDictionary)getPdfObject(trailer.get(PdfName.ROOT));
        this.rootPages = (PdfDictionary)getPdfObject(catalog.get(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;
    }

    /** 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(PdfWriter writer) {
        return new PdfReaderInstance(this, writer);
    }

    /** Gets the number of pages in the 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;
    }
    /**
     * 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(int index) {
        return getPageRotation(pageRefs.getPageNRelease(index));
    }

    int getPageRotation(PdfDictionary page) {
        PdfNumber rotate = (PdfNumber)getPdfObject(page.get(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(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(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(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(PdfDictionary page) {
        PdfArray mediaBox = (PdfArray)getPdfObject(page.get(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(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(int index, 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 getInfo() {
        HashMap map = new HashMap();
        PdfDictionary info = (PdfDictionary)getPdfObject(trailer.get(PdfName.INFO));
        if (info == null)
            return map;
        for (Iterator it = info.getKeys().iterator(); it.hasNext();) {
            PdfName key = (PdfName)it.next();
            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(PdfArray box) {
        ArrayList rect = box.getArrayList();
        float llx = ((PdfNumber)rect.get(0)).floatValue();
        float lly = ((PdfNumber)rect.get(1)).floatValue();
        float urx = ((PdfNumber)rect.get(2)).floatValue();
        float ury = ((PdfNumber)rect.get(3)).floatValue();
        return new Rectangle(Math.min(llx, urx), Math.min(lly, ury),
        Math.max(llx, urx), Math.max(lly, ury));
    }

    protected void readPdf() throws IOException {
        try {
            fileLength = tokens.getFile().length();
            pdfVersion = tokens.checkPdfHeader();
            try {
                readXref();
            }
            catch (Exception e) {
                try {
                    rebuilt = true;
                    rebuildXref();
                    lastXref = -1;
                }
                catch (Exception ne) {
                    throw new IOException("Rebuild failed: " + ne.getMessage() + "; Original message: " + e.getMessage());
                }
            }
            try {
                readDocObj();
            }
            catch (Exception ne) {
                if (rebuilt)
                    throw new IOException(ne.getMessage());
                rebuilt = true;
                encrypted = false;
                rebuildXref();
                lastXref = -1;
                readDocObj();
            }

            strings.clear();
            readPages();
            eliminateSharedStreams();
            removeUnusedObjects();
        }
        finally {
            try {
                tokens.close();
            }
            catch (Exception e) {
                // empty on purpose
            }
        }
    }

    protected void readPdfPartial() throws IOException {
        try {
            fileLength = tokens.getFile().length();
            pdfVersion = tokens.checkPdfHeader();
            try {
                readXref();
            }
            catch (Exception e) {
                try {
                    rebuilt = true;
                    rebuildXref();
                    lastXref = -1;
                }
                catch (Exception ne) {
                    throw new IOException("Rebuild failed: " + ne.getMessage() + "; Original message: " + e.getMessage());
                }
            }
            readDocObjPartial();
            readPages();
        }
        catch (IOException e) {
            try{tokens.close();}catch(Exception ee){}
            throw e;
        }
    }

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

    /**
     * @throws IOException
     */
    private void readDecryptedDocObj() throws IOException {
        if (encrypted)
            return;
        PdfObject encDic = trailer.get(PdfName.ENCRYPT);
        if (encDic == null || encDic.toString().equals("null"))
            return;
        byte[] encryptionKey = null;    	
        encrypted = true;
        PdfDictionary enc = (PdfDictionary)getPdfObject(encDic);

        String s;
        PdfObject o;

        PdfArray documentIDs = (PdfArray)getPdfObject(trailer.get(PdfName.ID));
        byte documentID[] = null;
        if (documentIDs != null) {
            o = (PdfObject)documentIDs.getArrayList().get(0);
            strings.remove(o);
            s = o.toString();
            documentID = com.lowagie.text.DocWriter.getISOBytes(s);
            if (documentIDs.size() > 1)
                strings.remove(documentIDs.getArrayList().get(1));
        }

        byte uValue[] = null;
        byte oValue[] = null;
        int cryptoMode = PdfWriter.ENCRYPTION_RC4_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.lowagie.text.DocWriter.getISOBytes(s);
            s = enc.get(PdfName.O).toString();
            strings.remove(enc.get(PdfName.O));
            oValue = com.lowagie.text.DocWriter.getISOBytes(s);

            o = enc.get(PdfName.R);
            if (!o.isNumber()) throw new IOException("Illegal R value.");
            rValue = ((PdfNumber)o).intValue();
            if (rValue != 2 && rValue != 3 && rValue != 4)
                throw new IOException("Unknown encryption type (" + rValue + ")");

            o = enc.get(PdfName.P);
            if (!o.isNumber()) throw new IOException("Illegal P value.");
            pValue = ((PdfNumber)o).intValue();
   
            if ( rValue == 3 ){
                o = enc.get(PdfName.LENGTH);
                if (!o.isNumber())
                    throw new IOException("Illegal Length value.");
                lengthValue = ( (PdfNumber) o).intValue();
                if (lengthValue > 128 || lengthValue < 40 || lengthValue % 8 != 0)
                    throw new IOException("Illegal Length value.");
                cryptoMode = PdfWriter.ENCRYPTION_RC4_128;
            }  else if (rValue == 4) {
                PdfDictionary dic = (PdfDictionary)enc.get(PdfName.CF);
                if (dic == null)
                    throw new IOException("/CF not found (encryption)");
                dic = (PdfDictionary)dic.get(PdfName.STDCF);
                if (dic == null)
                    throw new IOException("/StdCF not found (encryption)");
                if (PdfName.V2.equals(dic.get(PdfName.CFM)))
                    cryptoMode = PdfWriter.ENCRYPTION_RC4_128;
                else if (PdfName.AESV2.equals(dic.get(PdfName.CFM)))
                    cryptoMode = PdfWriter.ENCRYPTION_AES_128;
                else
                    throw new IOException("No compatible encryption found");
                PdfObject em = enc.get(PdfName.ENCRYPTMETADATA);
                if (em != null && em.toString().equals("false"))
                    cryptoMode |= PdfWriter.DO_NOT_ENCRYPT_METADATA;
            } else {
                cryptoMode = PdfWriter.ENCRYPTION_RC4_40;
            }
        } 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 IOException("Illegal V value.");
            int vValue = ((PdfNumber)o).intValue();
            if (vValue != 1 && vValue != 2 && vValue != 4)
                throw new IOException("Unknown encryption type V = " + rValue);

            if ( vValue == 2 ){
                o = enc.get(PdfName.LENGTH);
                if (!o.isNumber())
                    throw new IOException("Illegal Length value.");
                lengthValue = ( (PdfNumber) o).intValue();
                if (lengthValue > 128 || lengthValue < 40 || lengthValue % 8 != 0)
                    throw new IOException("Illegal Length value.");
                cryptoMode = PdfWriter.ENCRYPTION_RC4_128;                
                recipients = (PdfArray)enc.get(PdfName.RECIPIENTS);                                
            } else if (vValue == 4) {
                PdfDictionary dic = (PdfDictionary)enc.get(PdfName.CF);
                if (dic == null)
                    throw new IOException("/CF not found (encryption)");
                dic = (PdfDictionary)dic.get(PdfName.DEFAULTCRYPTFILER);
                if (dic == null)
                    throw new IOException("/DefaultCryptFilter not found (encryption)");
                if (PdfName.V2.equals(dic.get(PdfName.CFM)))
                {
                    cryptoMode = PdfWriter.ENCRYPTION_RC4_128;
                    lengthValue = 128;
                }
                else if (PdfName.AESV2.equals(dic.get(PdfName.CFM)))
                {
                    cryptoMode = PdfWriter.ENCRYPTION_AES_128;
                    lengthValue = 128;
                }
                else
                    throw new IOException("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);                                    
            } else {
                cryptoMode = PdfWriter.ENCRYPTION_RC4_40;
                lengthValue = 40;                
                recipients = (PdfArray)enc.get(PdfName.RECIPIENTS);                
            }

            for (int i = 0; i<recipients.size(); i++)
            {
                PdfObject recipient = (PdfObject)recipients.getArrayList().get(i);
                strings.remove(recipient);
                
                CMSEnvelopedData data = null;
                try {
                    data = new CMSEnvelopedData(recipient.getBytes());
                
                    Iterator recipientCertificatesIt = 
                        data.getRecipientInfos().getRecipients().iterator();
            
                    while (recipientCertificatesIt.hasNext()) {
                        RecipientInformation recipientInfo = 
                            (RecipientInformation)recipientCertificatesIt.next();

                        if (recipientInfo.getRID().match(certificate) && !foundRecipient) {
    
                         envelopedData = recipientInfo.getContent(certificateKey, certificateKeyProvider);
                         foundRecipient = true;                         
                        }
                    }                        
                } catch (Exception f) {
                    throw new ExceptionConverter(f);
                }            
            }
            
            if(!foundRecipient || envelopedData == null)
            {
                throw new IOException("Bad certificate and key.");
            }            

            MessageDigest md = null;

            try {
                md = MessageDigest.getInstance("SHA-1");
                md.update(envelopedData, 0, 20);
                for (int i=0; i<recipients.size(); i++)
                {
                  byte[] encodedRecipient = ((PdfObject)recipients.getArrayList().get(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))
        {
            //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 IOException("Bad user password");
                }
            }
            else
                ownerPasswordUsed = true;
        } else if (filter.equals(PdfName.PUBSEC)) {   
            decrypt.setupByEncryptionKey(encryptionKey, lengthValue);  
        }
                 
        for (int k = 0; k < strings.size(); ++k) {
            PdfString str = (PdfString)strings.get(k);
            str.decrypt(this);
        }
        
        if (encDic.isIndirect()) {
            cryptoRef = (PRIndirectReference)encDic;
            xrefObj.set(cryptoRef.getNumber(), null);
        }
    }

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

    /**
     * @param obj
     * @param parent
     * @return a PdfObject
     */
    public static PdfObject getPdfObject(PdfObject obj, 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(int idx) {
        PdfObject obj = getPdfObject(idx);
        releaseLastXrefPartial();
        return obj;
    }

    /**
     * @param idx
     * @return aPdfObject
     */
    public PdfObject getPdfObject(int idx) {
        try {
            lastXrefPartial = -1;
            if (idx < 0 || idx >= xrefObj.size())
                return null;
            PdfObject obj = (PdfObject)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(PdfObject obj) {
        if (obj == null)
            return;
        if (!obj.isIndirect())
            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(int idx, PdfObject obj) {
        if (!partial || idx < 0)
            return;
        xrefObj.set(idx, obj);
    }

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

    protected void readPages() throws IOException {
        pageInh = new ArrayList();
        catalog = (PdfDictionary)getPdfObject(trailer.get(PdfName.ROOT));
        rootPages = (PdfDictionary)getPdfObject(catalog.get(PdfName.PAGES));
        pageRefs = new PageRefs(this);
    }

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

    protected PdfObject readSingleObject(int k) throws IOException {
        strings.clear();
        int k2 = k * 2;
        int 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() != PRTokeniser.TK_NUMBER)
            tokens.throwError("Invalid object number.");
        objNum = tokens.intValue();
        tokens.nextValidToken();
        if (tokens.getTokenType() != PRTokeniser.TK_NUMBER)
            tokens.throwError("Invalid generation number.");
        objGen = tokens.intValue();
        tokens.nextValidToken();
        if (!tokens.getStringValue().equals("obj"))
            tokens.throwError("Token 'obj' expected.");
        PdfObject obj;
        try {
            obj = readPRObject();
            for (int j = 0; j < strings.size(); ++j) {
                PdfString str = (PdfString)strings.get(j);
                str.decrypt(this);
            }
            if (obj.isStream()) {
                checkPRStreamLength((PRStream)obj);
            }
        }
        catch (Exception e) {
            obj = null;
        }
        if (xref[k2 + 1] > 0) {
            obj = readOneObjStm((PRStream)obj, xref[k2]);
        }
        xrefObj.set(k, obj);
        return obj;
    }

    protected PdfObject readOneObjStm(PRStream stream, int idx) throws IOException {
        int first = ((PdfNumber)getPdfObject(stream.get(PdfName.FIRST))).intValue();
        byte b[] = getStreamBytes(stream, tokens.getFile());
        PRTokeniser saveTokens = tokens;
        tokens = new PRTokeniser(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() != PRTokeniser.TK_NUMBER) {
                    ok = false;
                    break;
                }
                ok = tokens.nextToken();
                if (!ok)
                    break;
                if (tokens.getTokenType() != PRTokeniser.TK_NUMBER) {
                    ok = false;
                    break;
                }
                address = tokens.intValue() + first;
            }
            if (!ok)
                throw new IOException("Error reading ObjStm");
            tokens.seek(address);
            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 streams = new ArrayList();
        xrefObj = new ArrayList(xref.length / 2);
        xrefObj.addAll(Collections.nCopies(xref.length / 2, null));
        for (int k = 2; k < xref.length; k += 2) {
            int pos = xref[k];
            if (pos <= 0 || xref[k + 1] > 0)
                continue;
            tokens.seek(pos);
            tokens.nextValidToken();
            if (tokens.getTokenType() != PRTokeniser.TK_NUMBER)
                tokens.throwError("Invalid object number.");
            objNum = tokens.intValue();
            tokens.nextValidToken();
            if (tokens.getTokenType() != PRTokeniser.TK_NUMBER)
                tokens.throwError("Invalid generation number.");
            objGen = tokens.intValue();
            tokens.nextValidToken();
            if (!tokens.getStringValue().equals("obj"))
                tokens.throwError("Token 'obj' expected.");
            PdfObject obj;
            try {
                obj = readPRObject();
                if (obj.isStream()) {
                    streams.add(obj);
                }
            }
            catch (Exception e) {
                obj = null;
            }
            xrefObj.set(k / 2, obj);
        }
        for (int k = 0; k < streams.size(); ++k) {
            checkPRStreamLength((PRStream)streams.get(k));
        }
        readDecryptedDocObj();
        if (objStmMark != null) {
            for (Iterator i = objStmMark.entrySet().iterator(); i.hasNext();) {
                Map.Entry entry = (Map.Entry)i.next();
                int n = ((Integer)entry.getKey()).intValue();
                IntHashtable h = (IntHashtable)entry.getValue();
                readObjStm((PRStream)xrefObj.get(n), h);
                xrefObj.set(n, null);
            }
            objStmMark = null;
        }
        xref = null;
    }

    private void checkPRStreamLength(PRStream stream) throws IOException {
        int fileLength = tokens.length();
        int start = stream.getOffset();
        boolean calc = false;
        int 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);
            while (true) {
                int pos = tokens.getFilePointer();
                if (!tokens.readLineSegment(tline))
                    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;
                }
            }
        }
        stream.setLength(streamLength);
    }

    protected void readObjStm(PRStream stream, IntHashtable map) throws IOException {
        int first = ((PdfNumber)getPdfObject(stream.get(PdfName.FIRST))).intValue();
        int n = ((PdfNumber)getPdfObject(stream.get(PdfName.N))).intValue();
        byte b[] = getStreamBytes(stream, tokens.getFile());
        PRTokeniser saveTokens = tokens;
        tokens = new PRTokeniser(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() != PRTokeniser.TK_NUMBER) {
                    ok = false;
                    break;
                }
                objNumber[k] = tokens.intValue();
                ok = tokens.nextToken();
                if (!ok)
                    break;
                if (tokens.getTokenType() != PRTokeniser.TK_NUMBER) {
                    ok = false;
                    break;
                }
                address[k] = tokens.intValue() + first;
            }
            if (!ok)
                throw new IOException("Error reading ObjStm");
            for (int k = 0; k < n; ++k) {
                if (map.containsKey(k)) {
                    tokens.seek(address[k]);
                    PdfObject 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(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(int size) {
        if (size == 0)
            return;
        if (xref == null)
            xref = new int[size];
        else {
            if (xref.length < size) {
                int xref2[] = new int[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 IOException("startxref not found.");
        tokens.nextToken();
        if (tokens.getTokenType() != PRTokeniser.TK_NUMBER)
            throw new IOException("startxref is not followed by a number.");
        int startxref = tokens.intValue();
        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;
            tokens.seek(prev.intValue());
            trailer2 = readXrefSection();
        }
    }

    protected PdfDictionary readXrefSection() throws IOException {
        tokens.nextValidToken();
        if (!tokens.getStringValue().equals("xref"))
            tokens.throwError("xref subsection not found");
        int start = 0;
        int end = 0;
        int pos = 0;
        int gen = 0;
        while (true) {
            tokens.nextValidToken();
            if (tokens.getStringValue().equals("trailer"))
                break;
            if (tokens.getTokenType() != PRTokeniser.TK_NUMBER)
                tokens.throwError("Object number of the first object in this xref subsection not found");
            start = tokens.intValue();
            tokens.nextValidToken();
            if (tokens.getTokenType() != PRTokeniser.TK_NUMBER)
                tokens.throwError("Number of entries in this xref subsection not found");
            end = tokens.intValue() + start;
            if (start == 1) { // fix incorrect start number
                int back = tokens.getFilePointer();
                tokens.nextValidToken();
                pos = tokens.intValue();
                tokens.nextValidToken();
                gen = tokens.intValue();
                if (pos == 0 && gen == 65535) {
                    --start;
                    --end;
                }
                tokens.seek(back);
            }
            ensureXrefSize(end * 2);
            for (int k = start; k < end; ++k) {
                tokens.nextValidToken();
                pos = tokens.intValue();
                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("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("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(int ptr) throws IOException {
        tokens.seek(ptr);
        int thisStream = 0;
        if (!tokens.nextToken())
            return false;
        if (tokens.getTokenType() != PRTokeniser.TK_NUMBER)
            return false;
        thisStream = tokens.intValue();
        if (!tokens.nextToken() || tokens.getTokenType() != PRTokeniser.TK_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);
        int prev = -1;
        obj = stm.get(PdfName.PREV);
        if (obj != null)
            prev = ((PdfNumber)obj).intValue();
        // 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();
        if (objStmToOffset == null && partial)
            objStmToOffset = new IntHashtable();
        byte b[] = getStreamBytes(stm, tokens.getFile());
        int bptr = 0;
        ArrayList wa = w.getArrayList();
        int wc[] = new int[3];
        for (int k = 0; k < 3; ++k)
            wc[k] = ((PdfNumber)wa.get(k)).intValue();
        ArrayList sections = index.getArrayList();
        for (int idx = 0; idx < sections.size(); idx += 2) {
            int start = ((PdfNumber)sections.get(idx)).intValue();
            int length = ((PdfNumber)sections.get(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);
                }
                int 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 = new Integer(field2);
                                IntHashtable seq = (IntHashtable)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 < xref.length)
            xref[thisStream] = -1;

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

    protected void rebuildXref() throws IOException {
        hybridXref = false;
        newXrefType = false;
        tokens.seek(0);
        int xr[][] = new int[1024][];
        int top = 0;
        trailer = null;
        byte line[] = new byte[64];
        for (;;) {
            int pos = tokens.getFilePointer();
            if (!tokens.readLineSegment(line))
                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') {
                int obj[] = PRTokeniser.checkObjectStart(line);
                if (obj == null)
                    continue;
                int num = obj[0];
                int gen = obj[1];
                if (num >= xr.length) {
                    int newLength = num * 2;
                    int xr2[][] = new int[newLength][];
                    System.arraycopy(xr, 0, xr2, 0, top);
                    xr = xr2;
                }
                if (num >= top)
                    top = num + 1;
                if (xr[num] == null || gen >= xr[num][1]) {
                    obj[0] = pos;
                    xr[num] = obj;
                }
            }
        }
        if (trailer == null)
            throw new IOException("trailer not found.");
        xref = new int[top * 2];
        for (int k = 0; k < top; ++k) {
            int 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() == PRTokeniser.TK_END_DIC)
                break;
            if (tokens.getTokenType() != PRTokeniser.TK_NAME)
                tokens.throwError("Dictionary key is not a name.");
            PdfName name = new PdfName(tokens.getStringValue(), false);
            PdfObject obj = readPRObject();
            int type = obj.type();
            if (-type == PRTokeniser.TK_END_DIC)
                tokens.throwError("Unexpected '>>'");
            if (-type == PRTokeniser.TK_END_ARRAY)
                tokens.throwError("Unexpected ']'");
            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 == PRTokeniser.TK_END_ARRAY)
                break;
            if (-type == PRTokeniser.TK_END_DIC)
                tokens.throwError("Unexpected '>>'");
            array.add(obj);
        }
        return array;
    }

    protected PdfObject readPRObject() throws IOException {
        tokens.nextValidToken();
        int type = tokens.getTokenType();
        switch (type) {
            case PRTokeniser.TK_START_DIC: {
                PdfDictionary dic = readDictionary();
                int pos = tokens.getFilePointer();
                // be careful in the trailer. May not be a "next" token.
                if (tokens.nextToken() && tokens.getStringValue().equals("stream")) {
                    int ch = tokens.read();
                    if (ch != '\n')
                        ch = tokens.read();
                    if (ch != '\n')
                        tokens.backOnePosition(ch);
                    PRStream stream = new PRStream(this, tokens.getFilePointer());
                    stream.putAll(dic);
                    stream.setObjNum(objNum, objGen);
                    return stream;
                }
                else {
                    tokens.seek(pos);
                    return dic;
                }
            }
            case PRTokeniser.TK_START_ARRAY:
                return readArray();
            case PRTokeniser.TK_NUMBER:
                return new PdfNumber(tokens.getStringValue());
            case PRTokeniser.TK_STRING:
                PdfString str = new PdfString(tokens.getStringValue(), null).setHexWriting(tokens.isHexString());
                str.setObjNum(objNum, objGen);
                if (strings != null)
                    strings.add(str);
                return str;
            case PRTokeniser.TK_NAME:
                return new PdfName(tokens.getStringValue(), false);
            case PRTokeniser.TK_REF:
                int num = tokens.getReference();
                PRIndirectReference ref = new PRIndirectReference(this, num, tokens.getGeneration());
                return ref;
            default:
                String sv = tokens.getStringValue();
                if ("null".equals(sv))
                    return PdfNull.PDFNULL;
                else if ("true".equals(sv))
                    return PdfBoolean.PDFTRUE;
                else if ("false".equals(sv))
                    return PdfBoolean.PDFFALSE;
                return new PdfLiteral(-type, tokens.getStringValue());
        }
    }

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

    /**
     * @param in
     * @param dicPar
     * @return a byte array
     */
    public static byte[] decodePredictor(byte in[], 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)
            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];

        // 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 -- uknown filter type
                    throw new RuntimeException("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(byte in[], boolean strict) {
        ByteArrayInputStream stream = new ByteArrayInputStream(in);
        InflaterInputStream zip = new InflaterInputStream(stream);
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        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 (Exception e) {
            if (strict)
                return null;
            return out.toByteArray();
        }
    }

    /** Decodes a stream that has the ASCIIHexDecode filter.
     * @param in the input data
     * @return the decoded data
     */
    public static byte[] ASCIIHexDecode(byte in[]) {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        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("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(byte in[]) {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        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("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;
        if (state == 1)
            throw new RuntimeException("Illegal length in ASCII85Decode.");
        if (state == 2) {
            r = chn[0] * 85 * 85 * 85 * 85 + chn[1] * 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;
            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 ;
            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(byte in[]) {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        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(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(int pageNum) {
        PdfDictionary dic = getPageN(pageNum);
        pageRefs.releasePage(pageNum);
        return dic;
    }

    /**
     * @param pageNum
     */
    public void releasePage(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(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(int pageNum, 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];
        ByteArrayOutputStream bout = null;
        if (contents.isStream()) {
            return getStreamBytes((PRStream)contents, file);
        }
        else if (contents.isArray()) {
            PdfArray array = (PdfArray)contents;
            ArrayList list = array.getArrayList();
            bout = new ByteArrayOutputStream();
            for (int k = 0; k < list.size(); ++k) {
                PdfObject item = getPdfObjectRelease((PdfObject)list.get(k));
                if (item == null || !item.isStream())
                    continue;
                byte[] b = getStreamBytes((PRStream)item, file);
                bout.write(b);
                if (k != list.size() - 1)
                    bout.write('\n');
            }
            return bout.toByteArray();
        }
        else
            return new byte[0];
    }

    /** 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(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 = (PdfObject)xrefObj.get(xr);
                xrefObj.set(xr, null);
                freeXref = xr;
                killXref(obj);
                break;
            }
            case PdfObject.ARRAY: {
                ArrayList t = ((PdfArray)obj).getArrayList();
                for (int i = 0; i < t.size(); ++i)
                    killXref((PdfObject)t.get(i));
                break;
            }
            case PdfObject.STREAM:
            case PdfObject.DICTIONARY: {
                PdfDictionary dic = (PdfDictionary)obj;
                for (Iterator i = dic.getKeys().iterator(); i.hasNext();){
                    killXref(dic.get((PdfName)i.next()));
                }
                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(int pageNum, byte content[]) {
        PdfDictionary page = getPageN(pageNum);
        if (page == null)
            return;
        PdfObject contents = page.get(PdfName.CONTENTS);
        freeXref = -1;
        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));
    }

    /** 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(PRStream stream, RandomAccessFileOrArray file) throws IOException {
        PdfObject filter = getPdfObjectRelease(stream.get(PdfName.FILTER));
        byte[] b = getStreamBytesRaw(stream, file);
        ArrayList filters = new ArrayList();
        if (filter != null) {
            if (filter.isName())
                filters.add(filter);
            else if (filter.isArray())
                filters = ((PdfArray)filter).getArrayList();
        }
        ArrayList dp = new ArrayList();
        PdfObject dpo = getPdfObjectRelease(stream.get(PdfName.DECODEPARMS));
        if (dpo == null || (!dpo.isDictionary() && !dpo.isArray()))
            dpo = getPdfObjectRelease(stream.get(PdfName.DP));
        if (dpo != null) {
            if (dpo.isDictionary())
                dp.add(dpo);
            else if (dpo.isArray())
                dp = ((PdfArray)dpo).getArrayList();
        }
        String name;
        for (int j = 0; j < filters.size(); ++j) {
            name = ((PdfName)getPdfObjectRelease((PdfObject)filters.get(j))).toString();
            if (name.equals("/FlateDecode") || name.equals("/Fl")) {
                b = FlateDecode(b);
                PdfObject dicParam = null;
                if (j < dp.size()) {
                    dicParam = (PdfObject)dp.get(j);
                    b = decodePredictor(b, dicParam);
                }
            }
            else if (name.equals("/ASCIIHexDecode") || name.equals("/AHx"))
                b = ASCIIHexDecode(b);
            else if (name.equals("/ASCII85Decode") || name.equals("/A85"))
                b = ASCII85Decode(b);
            else if (name.equals("/LZWDecode")) {
                b = LZWDecode(b);
                PdfObject dicParam = null;
                if (j < dp.size()) {
                    dicParam = (PdfObject)dp.get(j);
                    b = decodePredictor(b, dicParam);
                }
            }
            else if (name.equals("/Crypt")) {
            }
            else
                throw new IOException("The filter " + name + " is not supported.");
        }
        return b;
    }

    /** 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(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(PRStream stream, 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 filters = new ArrayList();
                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((PdfObject)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(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 newRefs = new ArrayList();
        ArrayList newStreams = new ArrayList();
        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;
                ArrayList list = array.getArrayList();
                for (int j = 0; j < list.size(); ++j) {
                    PRIndirectReference ref = (PRIndirectReference)list.get(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 = (PRIndirectReference)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(boolean tampered) {
        this.tampered = tampered;
    }

    /** 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 int 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 int 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 int 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(byte a1[], 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(PdfDictionary dic, PdfName key, 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(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(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 = (PdfDictionary)getPdfObject(dic.get(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 = (PdfArray)getPdfObject(dic.get(PdfName.DESCENDANTFONTS));
                if (arr == null)
                    continue;
                ArrayList list = arr.getArrayList();
                if (list.isEmpty())
                    continue;
                PdfDictionary desc = (PdfDictionary)getPdfObject((PdfObject)list.get(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 = (PdfDictionary)getPdfObject(desc.get(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 = (PdfDictionary)getPdfObject(dic.get(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 getNamedDestination() {
        HashMap names = getNamedDestinationFromNames();
        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
     */
    public HashMap getNamedDestinationFromNames() {
        HashMap names = new HashMap();
        if (catalog.get(PdfName.DESTS) != null) {
            PdfDictionary dic = (PdfDictionary)getPdfObjectRelease(catalog.get(PdfName.DESTS));
            if (dic == null)
                return names;
            Set keys = dic.getKeys();
            for (Iterator it = keys.iterator(); it.hasNext();) {
                PdfName key = (PdfName)it.next();
                String name = PdfName.decodeName(key.toString());
                PdfArray arr = getNameArray(dic.get(key));
                if (arr != null)
                    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 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 names = PdfNameTree.readTree(dic);
                    for (Iterator it = names.entrySet().iterator(); it.hasNext();) {
                        Map.Entry entry = (Map.Entry)it.next();
                        PdfArray arr = getNameArray((PdfObject)entry.getValue());
                        if (arr != null)
                            entry.setValue(arr);
                        else
                            it.remove();
                    }
                    return names;
                }
            }
        }
        return new HashMap();
    }

    private boolean replaceNamedDestination(PdfObject obj, HashMap names) {
        obj = getPdfObject(obj);
        int objIdx = lastXrefPartial;
        releaseLastXrefPartial();
        if (obj != null && obj.isDictionary()) {
            PdfObject ob2 = getPdfObjectRelease(((PdfDictionary)obj).get(PdfName.DEST));
            String name = null;
            if (ob2 != null) {
                if (ob2.isName())
                    name = PdfName.decodeName(ob2.toString());
                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 = PdfName.decodeName(ob3.toString());
                        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;
    }

    /**
     * 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 = (PdfArray)getPdfObject(page.get(PdfName.ANNOTS));
            if (annots == null) {
                pageRefs.releasePage(k);
                continue;
            }
            ArrayList arr = annots.getArrayList();
            for (int j = 0; j < arr.size(); ++j) {
                PdfDictionary annot = (PdfDictionary)getPdfObjectRelease((PdfObject)arr.get(j));
                if (PdfName.WIDGET.equals(annot.get(PdfName.SUBTYPE)))
                    arr.remove(j--);
            }
            if (arr.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();
    }

    private void iterateBookmarks(PdfObject outlineRef, HashMap 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 all the local named links with the actual destinations. */
    public void consolidateNamedDestinations() {
        if (consolidateNamedDestinations)
            return;
        consolidateNamedDestinations = true;
        HashMap names = getNamedDestination();
        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;
            }
            ArrayList list = annots.getArrayList();
            boolean commitAnnots = false;
            for (int an = 0; an < list.size(); ++an) {
                PdfObject objRef = (PdfObject)list.get(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);
    }

    protected static PdfDictionary duplicatePdfDictionary(PdfDictionary original, PdfDictionary copy, PdfReader newReader) {
        if (copy == null)
            copy = new PdfDictionary();
        for (Iterator it = original.getKeys().iterator(); it.hasNext();) {
            PdfName key = (PdfName)it.next();
            copy.put(key, duplicatePdfObject(original.get(key), newReader));
        }
        return copy;
    }

    protected static PdfObject duplicatePdfObject(PdfObject original, 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: {
                ArrayList list = ((PdfArray)original).getArrayList();
                PdfArray arr = new PdfArray();
                for (Iterator it = list.iterator(); it.hasNext();) {
                    arr.add(duplicatePdfObject((PdfObject)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
     */
    public void close() {
        if (!partial)
            return;
        try {
            tokens.close();
        }
        catch (IOException e) {
            throw new ExceptionConverter(e);
        }
    }

    protected void removeUnusedNode(PdfObject obj, boolean hits[]) {
        Stack state = new Stack();
        state.push(obj);
        while (!state.empty()) {
            Object current = state.pop();
            if (current == null)
                continue;
            ArrayList 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)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 = (PdfObject)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, new Integer(k + 1)});
                    else {
                        objs[1] = new Integer(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 >= xrefObj.size() || (!partial && xrefObj.get(num) == null)) {
                            dic.put(key, PdfNull.PDFNULL);
                            continue;
                        }
                    }
                    if (objs == null)
                        state.push(new Object[]{keys, dic, new Integer(k + 1)});
                    else {
                        objs[2] = new Integer(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(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 jscript = PdfNameTree.readTree(js);
        String sortedNames[] = new String[jscript.size()];
        sortedNames = (String[])jscript.keySet().toArray(sortedNames);
        Arrays.sort(sortedNames);
        StringBuffer buf = new StringBuffer();
        for (int k = 0; k < sortedNames.length; ++k) {
            PdfDictionary j = (PdfDictionary)getPdfObjectRelease((PdfIndirectReference)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(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(List pagesToKeep) {
        pageRefs.selectPages(pagesToKeep);
        removeUnusedObjects();
    }

    /** Sets the viewer preferences as the sum of several constants.
     * @param preferences the viewer preferences
     * @see PdfViewerPreferences#setViewerPreferences
     */
    public void setViewerPreferences(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(PdfName key, PdfObject value) {
    	this.viewerPreferences.addViewerPreference(key, value);
        setViewerPreferences(this.viewerPreferences);
    }
    
    void setViewerPreferences(PdfViewerPreferencesImp vp) {
    	vp.addToCatalog(catalog);
    }

    /**
     * @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(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 int getFileLength() {
        return fileLength;
    }

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

    static class PageRefs {
        private PdfReader reader;
        private IntHashtable refsp;
        private ArrayList refsn;
        private ArrayList pageInh;
        private int lastPageRead = -1;
        private int sizep;

        private PageRefs(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(PageRefs other, PdfReader reader) {
            this.reader = reader;
            this.sizep = other.sizep;
            if (other.refsn != null) {
                refsn = new ArrayList(other.refsn);
                for (int k = 0; k < refsn.size(); ++k) {
                    refsn.set(k, duplicatePdfObject((PdfObject)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();
            pageInh = new ArrayList();
            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(int pageNum) {
            PRIndirectReference ref = getPageOrigRef(pageNum);
            return (PdfDictionary)PdfReader.getPdfObject(ref);
        }

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

        /**
         * @param pageNum
         * @return an indirect reference
         */
        public PRIndirectReference getPageOrigRefRelease(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 (PRIndirectReference)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());
                        return ref;
                    }
                    else {
                        if (lastPageRead != pageNum)
                            lastPageRead = -1;
                        return new PRIndirectReference(reader, n);
                    }
                }
            }
            catch (Exception e) {
                throw new ExceptionConverter(e);
            }
        }

        /**
         * @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, 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 it = refsp.getEntryIterator(); it.hasNext();) {
                        IntHashtable.Entry entry = (IntHashtable.Entry)it.next();
                        int p = entry.getKey();
                        refs2.put(p >= pageNum ? p + 1 : p, entry.getValue());
                    }
                    refs2.put(pageNum, ref.getNumber());
                    refsp = refs2;
                }
            }
        }

        private void pushPageAttributes(PdfDictionary nodePages) {
            PdfDictionary dic = new PdfDictionary();
            if (!pageInh.isEmpty()) {
                dic.putAll((PdfDictionary)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);
        }

        private void popPageAttributes() {
            pageInh.remove(pageInh.size() - 1);
        }

        private void iteratePages(PRIndirectReference rpage) throws IOException {
            PdfDictionary page = (PdfDictionary)getPdfObject(rpage);
            PdfArray kidsPR = (PdfArray)getPdfObject(page.get(PdfName.KIDS));
            if (kidsPR == null) {
                page.put(PdfName.TYPE, PdfName.PAGE);
                PdfDictionary dic = (PdfDictionary)pageInh.get(pageInh.size() - 1);
                PdfName key;
                for (Iterator i = dic.getKeys().iterator(); i.hasNext();) {
                    key = (PdfName)i.next();
                    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.right(),PageSize.LETTER.top()});
                    page.put(PdfName.MEDIABOX, arr);
                }
                refsn.add(rpage);
            }
            else {
                page.put(PdfName.TYPE, PdfName.PAGES);
                pushPageAttributes(page);
                ArrayList kids = kidsPR.getArrayList();
                for (int k = 0; k < kids.size(); ++k){
                    PdfObject obj = (PdfObject)kids.get(k);
                    if (!obj.isIndirect()) {
                        while (k < kids.size())
                            kids.remove(k);
                        break;
                    }
                    iteratePages((PRIndirectReference)obj);
                }
                popPageAttributes();
            }
        }

        protected PRIndirectReference getSinglePage(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 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(List pagesToKeep) {
            IntHashtable pg = new IntHashtable();
            ArrayList finalPages = new ArrayList();
            int psize = size();
            for (Iterator it = pagesToKeep.iterator(); it.hasNext();) {
                Integer pi = (Integer)it.next();
                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 newPageRefs = new ArrayList(finalPages.size());
            PdfArray kids = new PdfArray();
            for (int k = 0; k < finalPages.size(); ++k) {
                int p = ((Integer)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());
    }
    
    /**
     * 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 advisabe to remove them altogether.
     */
    public void removeUsageRights() {
        PdfDictionary perms = (PdfDictionary)getPdfObject(catalog.get(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 availabe for that in <CODE>AcroFields</CODE>.
     * </p>
     * @return gets the certification level for this document
     */
    public int getCertificationLevel() {
        PdfDictionary dic = (PdfDictionary)getPdfObject(catalog.get(PdfName.PERMS));
        if (dic == null)
            return PdfSignatureAppearance.NOT_CERTIFIED;
        dic = (PdfDictionary)getPdfObject(dic.get(PdfName.DOCMDP));
        if (dic == null)
            return PdfSignatureAppearance.NOT_CERTIFIED;
        PdfArray arr = (PdfArray)getPdfObject(dic.get(PdfName.REFERENCE));
        if (arr == null || arr.size() == 0)
            return PdfSignatureAppearance.NOT_CERTIFIED;
        dic = (PdfDictionary)getPdfObject((PdfObject)(arr.getArrayList().get(0)));
        if (dic == null)
            return PdfSignatureAppearance.NOT_CERTIFIED;
        dic = (PdfDictionary)getPdfObject(dic.get(PdfName.TRANSFORMPARAMS));
        if (dic == null)
            return PdfSignatureAppearance.NOT_CERTIFIED;
        PdfNumber p = (PdfNumber)getPdfObject(dic.get(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 boolean isOpenedWithFullPermissions() {
        return !encrypted || ownerPasswordUsed;
    }
    
    public int getCryptoMode() {
    	if (decrypt == null) 
    		return -1;
    	else 
    		return decrypt.getCryptoMode();
    }
    
    public boolean isMetadataEncrypted() {
    	if (decrypt == null) 
    		return false; 
    	else 
    		return decrypt.isMetadataEncrypted();
    }
    
    public byte[] computeUserPassword() {
    	if (!encrypted || !ownerPasswordUsed) return null;
    	return decrypt.computeUserPassword(password);
    }
}