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An Open Source JavaFX PDF Viewer
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/*
 * ===========================================
 * Java Pdf Extraction Decoding Access Library
 * ===========================================
 *
 * Project Info:  http://www.idrsolutions.com
 * Help section for developers at http://www.idrsolutions.com/support/
 *
 * (C) Copyright 1997-2016 IDRsolutions and Contributors.
 *
 * This file is part of JPedal/JPDF2HTML5
 *
     This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


 *
 * ---------------
 * LinearThread.java
 * ---------------
 */
package org.jpedal.linear;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import org.jpedal.FileAccess;
import org.jpedal.io.LinearizedHintTable;
import org.jpedal.io.PdfObjectReader;
import org.jpedal.objects.raw.PdfDictionary;
import org.jpedal.objects.raw.PdfObject;
import org.jpedal.utils.LogWriter;
import org.jpedal.utils.NumberUtils;

/**
 * handles download of rest of file in Linearized mode
 */
public class LinearThread extends Thread {

    public int percentageDone;

    final FileChannel fos;
    final PdfObject linearObj;
    final InputStream is;
    final File tempURLFile;
    final LinearizedHintTable linHintTable;

    final byte[] startObj= {'o','b','j'},endObj= {'e','n','d','o','b','j'};
    int startCharReached, endCharReached;
    int startObjPtr,endObjPtr;

    //use top line to slow down load speed
    public static int bufSize=8192;

    int ref;
    final int firstObjLength;

    final FileAccess fileAccess;
    
    final byte[] linearBytes;
    

    public LinearThread(final InputStream is, final FileChannel fos, final File tempURLFile, final PdfObject linearObj, final byte[] linearBytes, final LinearizedHintTable linHintTable, final FileAccess fileAccess) {

        this.fos=fos;
        this.linearObj=linearObj;
        this.is=is;
        this.tempURLFile=tempURLFile;
        this.linHintTable=linHintTable;
        
        this.linearBytes=linearBytes;

        this.fileAccess=fileAccess;

        //scan start of file for objects
        firstObjLength=linearBytes.length;

        scanStreamForObjects(0, null, linearBytes);

        this.setDaemon(true);

    }

    public int getPercentageLoaded(){
        return percentageDone;
    }

    @Override
    public void run() {

        final int linearfileLength=linearObj.getInt(PdfDictionary.L);

        try{

            int read,bytesRead=0;

            //we cache last few bytes incase ref rolls across boundary
            byte[] lastBuffer=linearBytes;//new byte[lastBytes];
            
            byte[] buffer = new byte[bufSize];
            byte[] b;
            while ((read = is.read(buffer)) != -1 && !this.isInterrupted() && isAlive()) {

                if(read>0){
                    synchronized (fos){

                        b=new byte[read];
                        System.arraycopy(buffer,0,b,0,read);
                        buffer=b;
                        final ByteBuffer f=ByteBuffer.wrap(b);
                        fos.write(f);
                    }
                }

                //track start endobj and flag so we know if object read
                if(read>0){
                    scanStreamForObjects(firstObjLength+bytesRead, lastBuffer, buffer);

                    bytesRead += read;

                    //save last few bytes incase of overlap
                    int aa=30;

                    final int size1=buffer.length;

                    if(aa>size1-1) {
                        aa = size1 - 1;
                    }

                    lastBuffer=new byte[aa];
                    System.arraycopy(buffer, size1-aa, lastBuffer,0,aa);
                }

                percentageDone= (int) (100*(bytesRead/(float)linearfileLength));

                //debug code to simulate slow file stream by slowing down read of data from file
               // System.out.println("percentage="+percentageDone);
//                try {
//                    Thread.sleep(2000);
//                } catch (InterruptedException e) {
//                    e.printStackTrace();
//                }

            }

            linHintTable.setFinishedReading();


        } catch (final IOException e) {
            LogWriter.writeLog("Exception: " + e.getMessage());
        } finally{

            try{
                is.close();
                synchronized (fos){
                    fos.close();
                }
                //possible that page still being decoded on slower machine so wait
                fileAccess.waitForDecodingToFinish();

                fileAccess.setIO(new PdfObjectReader());

                /* get reader object to open the file if all downloaded*/
                if(isAlive() && !isInterrupted()){
                    fileAccess.openPdfFile(tempURLFile.getAbsolutePath());

                    /* store fi name for use elsewhere as part of ref key without .pdf */
                    fileAccess.getObjectStore().storeFileName(tempURLFile.getName().substring(0, tempURLFile.getName().lastIndexOf('.')));
                }

            }catch(final Exception e){
                LogWriter.writeLog("Exception: " + e.getMessage());
            }
        }
    }

    private void scanStreamForObjects(final int bytesRead, final byte[] lastBuffer, final byte[] buffer) {

        final int bufSize=buffer.length;

        for(int i=0;i