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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
*
* ---------------
* ObjectReader.java
* ---------------
*/
package org.jpedal.io.types;
import java.io.IOException;
import org.jpedal.io.ObjectUtils;
import org.jpedal.io.PdfFileReader;
import org.jpedal.io.RandomAccessBuffer;
import org.jpedal.objects.raw.PdfObject;
import org.jpedal.utils.LogWriter;
/**
*
*/
public class ObjectReader {
public boolean fileIsBroken;
static final byte[] endPattern = { 101, 110, 100, 111, 98, 106 }; //pattern endobj
public static final byte[] lengthString = { 47, 76, 101, 110, 103, 116, 104}; //pattern /Length
public static final byte[] startStream = { 115, 116, 114, 101, 97, 109};
private final RandomAccessBuffer pdf_datafile;
private int newCacheSize=-1;
private final long eof;
final PdfFileReader currentPdfFile;
public ObjectReader(final RandomAccessBuffer pdf_datafile, final long eof, final PdfFileReader currentPdfFile) {
this.pdf_datafile=pdf_datafile;
this.eof=eof;
this.currentPdfFile=currentPdfFile;
}
public byte[] readObjectData(int bufSize, final PdfObject pdfObject){
//old version
if(bufSize<1 || newCacheSize!=-1 || fileIsBroken) {
return readUnsizedObjectData(bufSize, pdfObject);
}
byte[] dataRead=null;
//trap for odd file with no endobj
if(bufSize>0){
bufSize += 6;
dataRead = new byte[bufSize];
try{
pdf_datafile.read(dataRead);
} catch (final IOException ex) {
LogWriter.writeLog("Unable to fill buffer "+ex);
}
}
return dataRead;
}
private byte[] readUnsizedObjectData(int bufSize, final PdfObject pdfObject){
int newCacheSize=-1,startStreamCount=0,charReached = 0,charReached3=0;
boolean startStreamFound=false;
boolean reachedCacheLimit=false;
final boolean inStream=false;
boolean inLoop=true;
if(pdfObject!=null) //only use if values found
{
newCacheSize = this.newCacheSize;
}
final int rawSize=bufSize;
int realPos=0;
boolean lengthSet=false; //start false and set to true if we find /Length in metadata
if(bufSize<1) {
bufSize = 128;
}
if(newCacheSize!=-1 && bufSize>newCacheSize) {
bufSize = newCacheSize;
}
byte[] dataRead=null;
byte currentByte ;
int i=bufSize-1;
/*read the object or block adjust buffer if less than bytes left in file*/
while (inLoop) {
i++;
if(i==bufSize){
/* read the next block and adjust buffer if less than bytes left in file*/
final long pointer = getPointer();
if (pointer + bufSize > eof) {
bufSize = (int) (eof - pointer);
}
//trap for odd file with no endobj
if(bufSize==0) {
break;
}
bufSize += 6;
byte[] buffer = new byte[bufSize];
try {
pdf_datafile.read(buffer); //get data
} catch (final IOException ex) {
LogWriter.writeLog("Unable to fill buffer "+ex);
}
/*
* allow for offset being wrong on first block and hitting part of endobj and cleanup so does not break later code
* and set DataRead to buffer
*/
if (dataRead==null) {
int j = 0;
//check first 10 bytes
for(int i2=0;i2<10;i2++){
if(buffer[i2] == 'e' && buffer[i2+1] == 'n' && buffer[i2+2] == 'd' && buffer[i2+3] == 'o' && buffer[i2+4] == 'b' && buffer[i2+5] == 'j'){
j=i2;
break;
}
}
while (buffer[j] == 'e' || buffer[j] == 'n' || buffer[j] == 'd' || buffer[j] == 'o' || buffer[j] == 'b' || buffer[j] == 'j') {
j++;
}
if (j > 0) { //adjust to remove stuff at start
final byte[] oldBuffer = buffer;
final int newLength = buffer.length - j;
buffer = new byte[newLength];
System.arraycopy(oldBuffer, j, buffer, 0, newLength);
bufSize=buffer.length;
}
dataRead=buffer;
}else{
dataRead = appendDataBlock(buffer.length,buffer, dataRead);
}
i=0;
}
currentByte = dataRead[realPos];
if(!inStream){ //check for endobj at end - reset if not
if (currentByte == endPattern[charReached]) {
charReached++;
} else{
charReached = 0;
}
}
//look for start of stream and set inStream true
if(!startStreamFound && newCacheSize!=-1 && !reachedCacheLimit){
if (startStreamCount<6 && currentByte == startStream[startStreamCount]){
startStreamCount++;
if(startStreamCount == 6) //stream start found so log
{
startStreamFound = true;
}
}else {
startStreamCount = 0;
}
}
//switch on caching
if(!reachedCacheLimit && startStreamFound && dataRead!=null &&dataRead.length>newCacheSize){ //stop if over max size
if(!reachedCacheLimit) { //only set on first time
pdfObject.setCache(currentPdfFile);
}
reachedCacheLimit=true;
}
//also scan for /Length if it had a valid size - if length not set we go on endstream in data
if(!startStreamFound && !lengthSet && rawSize!=-1){
if(currentByte == lengthString[charReached3] && !inStream){
charReached3++;
if(charReached3==6) {
lengthSet = true;
}
}else {
charReached3 = 0;
}
}
realPos++;
if (charReached == 6){
if(!lengthSet) {
inLoop = false;
}
charReached=0;
}
if(lengthSet && realPos>rawSize) {
inLoop = false;
}
}
if(!lengthSet) {
dataRead = ObjectUtils.checkEndObject(dataRead);
}
return dataRead;
}
static byte[] appendDataBlock( final int newBytes, final byte[] buffer, final byte[] dataRead) {
final int bytesRead=dataRead.length;
final byte[] tmp=new byte[bytesRead+newBytes];
//existing data into new array
System.arraycopy(dataRead, 0, tmp, 0, bytesRead);
System.arraycopy(buffer, 0, tmp, bytesRead, newBytes);
return tmp;
}
//////////////////////////////////////////////////
/**
* gets pointer to current location in the file
*/
private long getPointer()
{
long old_pointer = 0;
try{
old_pointer = pdf_datafile.getFilePointer();
}catch( final Exception e ){
LogWriter.writeLog("Exception " + e + " getting pointer in file");
}
return old_pointer;
}
/**
* set size over which objects kept on disk
*/
public void setCacheSize(final int miniumumCacheSize) {
newCacheSize=miniumumCacheSize;
}
}
