de.intarsys.pdf.st.XRefStreamParser Maven / Gradle / Ivy
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This is a fork of http://sourceforge.net/projects/jpodlib/ as development seems to be frozen.
We're providing some bug fixes along with deployments to maven.
/*
* Copyright (c) 2007, intarsys consulting GmbH
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* - Neither the name of intarsys nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package de.intarsys.pdf.st;
import de.intarsys.pdf.cos.COSArray;
import de.intarsys.pdf.cos.COSIndirectObject;
import de.intarsys.pdf.cos.COSInteger;
import de.intarsys.pdf.cos.COSNumber;
import de.intarsys.pdf.cos.COSObject;
import de.intarsys.pdf.cos.COSStream;
import de.intarsys.pdf.parser.COSDocumentParser;
import de.intarsys.pdf.parser.COSLoadException;
import de.intarsys.tools.randomaccess.IRandomAccess;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.Iterator;
/**
* A parser for XRef streams.
*/
public class XRefStreamParser extends AbstractXRefParser {
private int[] wSizeDefault = {1, 2, 1};
private int[] wSize;
private ByteArrayInputStream in;
public XRefStreamParser(STDocument doc, COSDocumentParser parser) {
super(doc, parser);
}
private void initWBytes(STStreamXRefSection xRef) {
COSArray w = xRef.getW();
if (w == null) {
wSize = wSizeDefault;
return;
}
wSize = new int[3];
for (int i = 0; i < w.size(); i++) {
wSize[i] = ((COSInteger) w.get(i)).intValue();
}
for (int i = w.size(); i < 3; i++) {
wSize[i] = 0;
}
}
protected void loadPrevious(IRandomAccess randomAccess, STXRefSection xRefSection)
throws IOException, COSLoadException {
int offset = xRefSection.getPreviousOffset();
if (offset != -1) {
AbstractXRefParser parser = new XRefStreamParser(getDoc(), getParser());
randomAccess.seek(offset);
STXRefSection xrefStream = parser.parse(randomAccess);
xRefSection.setPrevious(xrefStream);
}
}
/*
* (non-Javadoc)
*
* @see de.intarsys.pdf.st.AbstractXRefParser#parse(de.intarsys.tools.randomaccess.IRandomAccess)
*/
@Override
public STXRefSection parse(IRandomAccess randomAcces) throws IOException, COSLoadException {
STXRefSection xRefSection = parseXRef(randomAcces);
loadPrevious(randomAcces, xRefSection);
return xRefSection;
}
private void parseStreamContent(STStreamXRefSection section) {
initWBytes(section);
in = new ByteArrayInputStream(section.cosGetStream().getDecodedBytes());
COSArray index = section.getIndex();
for (Iterator i = index.iterator(); i.hasNext(); ) {
COSNumber cosStart = ((COSObject) i.next()).asNumber();
if (!i.hasNext()) {
continue;
}
COSNumber cosCount = ((COSObject) i.next()).asNumber();
if (cosStart == null || cosCount == null) {
continue;
}
int start = cosStart.intValue();
int count = cosCount.intValue();
for (int io = 0; io < count; io++) {
int type = readType(in);
switch (type) {
case 0:
section.addEntry(parseType0(in, start + io));
break;
case 1:
section.addEntry(parseType1(in, start + io));
break;
case 2:
section.addEntry(parseType2(in, start + io));
break;
default:
parseTypeUnknown(in);
}
}
}
}
private STXRefEntry parseType0(ByteArrayInputStream pIn, int objectNumber) {
int nextFree = read(pIn, wSize[1], -1);
int nextGenNum = read(pIn, wSize[2], -1);
return new STXRefEntryFree(objectNumber, nextGenNum, nextFree);
}
private STXRefEntry parseType1(ByteArrayInputStream pIn, int objectNumber) {
int offset = read(pIn, wSize[1], -1);
int genNum = read(pIn, wSize[2], 0);
return new STXRefEntryOccupied(objectNumber, genNum, offset);
}
private STXRefEntry parseType2(ByteArrayInputStream pIn, int objectNumber) {
int streamObjectNumber = read(pIn, wSize[1], -1);
int indexOfObject = read(pIn, wSize[2], 0);
return new STXRefEntryCompressed(objectNumber, 0, streamObjectNumber, 0, indexOfObject);
}
private void parseTypeUnknown(ByteArrayInputStream pIn) {
read(pIn, wSize[1], -1);
read(pIn, wSize[1], -1);
}
protected STXRefSection parseXRef(IRandomAccess randomAcces) throws IOException, COSLoadException {
long offset = randomAcces.getOffset();
// no security handler - /XRef streams may not be encrypted
COSStream stream = (COSStream) getDoc().getParser().parseIndirectObject(randomAcces, null);
((COSIndirectObject) stream.containable()).setDirty(false);
STStreamXRefSection xRefSection = new STStreamXRefSection(getDoc(), offset, stream);
parseStreamContent(xRefSection);
return xRefSection;
}
private int read(ByteArrayInputStream pIn, int numBytes, int defaultValue) {
if (numBytes == 0) {
return defaultValue;
}
int result = 0;
for (int i = 0; i < numBytes; i++) {
result <<= 8;
result += pIn.read();
}
return result;
}
private int readType(ByteArrayInputStream pIn) {
return read(pIn, wSize[0], 1);
}
}