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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 1997-2017 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;
}
}
