de.intarsys.pdf.st.XRefTrailerParser 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.parser.COSDocumentParser;
import de.intarsys.pdf.parser.COSLoadError;
import de.intarsys.pdf.parser.COSLoadException;
import de.intarsys.pdf.parser.COSLoadWarning;
import de.intarsys.pdf.parser.PDFParser;
import de.intarsys.tools.randomaccess.IRandomAccess;
import java.io.IOException;
import java.util.Arrays;
/**
* A parser for XRef objects in "classical" format.
*/
public class XRefTrailerParser extends AbstractXRefParser {
public XRefTrailerParser(STDocument doc, COSDocumentParser parser) {
super(doc, parser);
}
protected void loadPrevious(IRandomAccess randomAccess, STXRefSection xRefSection)
throws IOException, COSLoadException {
int xrefStreamOffset = xRefSection.getXRefStmOffset();
if (xrefStreamOffset != -1) {
// this is for the mixed mode
AbstractXRefParser parser = new XRefStreamParser(getDoc(), getParser());
randomAccess.seek(xrefStreamOffset);
try {
STStreamXRefSection xrefStream = (STStreamXRefSection) parser.parse(randomAccess);
((STTrailerXRefSection) xRefSection).setXRefStream(xrefStream);
} catch (Exception e) {
// todo create message
// ignore, just like adobe does...
}
}
int offset = xRefSection.getPreviousOffset();
if (offset != -1) {
AbstractXRefParser parser = new XRefTrailerParser(getDoc(), getParser());
randomAccess.seek(offset);
STXRefSection trailer = parser.parse(randomAccess);
xRefSection.setPrevious(trailer);
}
}
/*
* (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 STXRefEntry parseEntry(int objectNumber, byte[] entryBytes) {
int offset = 0;
for (int i = 0; i < 10; i++) {
offset = (offset * 10) + (entryBytes[i] - '0');
}
int generation = 0;
for (int i = 11; i < 16; i++) {
generation = (generation * 10) + (entryBytes[i] - '0');
}
boolean inuse = (entryBytes[17] == 'n');
if (inuse) {
return new STXRefEntryOccupied(objectNumber, generation, offset);
}
return new STXRefEntryFree(objectNumber, generation, offset);
}
protected STXRefSection parseXRef(IRandomAccess randomAccess) throws IOException, COSLoadException {
STTrailerXRefSection xRefSection = new STTrailerXRefSection(getDoc(), randomAccess.getOffset());
parseXRefSection(randomAccess, xRefSection);
xRefSection.cosSetDict(getDoc().getParser().parseTrailer(randomAccess));
return xRefSection;
}
protected void parseXRefSection(IRandomAccess randomAccess, STTrailerXRefSection xRef)
throws IOException, COSLoadException {
getDoc().getParser().readSpaces(randomAccess);
byte[] token = new byte[4];
randomAccess.read(token);
if (Arrays.equals(token, PDFParser.TOKEN_xref)) {
token = new byte[PDFParser.TOKEN_trailer.length];
long oldpos = -1;
long pos = randomAccess.getOffset();
// break from loop if we seem to repeat ourself
while (oldpos != pos) {
oldpos = pos;
parseXRefSubsection(randomAccess, xRef);
// maybe we got out of synch while stupidly parsing xref
// todo 3 @kkr seems compliant, verify with test suite documents
// once available
getDoc().getParser().readSpaces(randomAccess);
int c = randomAccess.read();
randomAccess.seekBy(-1);
if ((c == -1) || !PDFParser.isDigit(c)) {
break;
}
pos = randomAccess.getOffset();
}
} else {
COSLoadError e = new COSLoadError("no 'xref' key found at character index " + randomAccess.getOffset());
handleError(e);
}
}
protected void parseXRefSubsection(IRandomAccess randomAccess, STTrailerXRefSection xRef)
throws IOException, COSLoadException {
// read begining
int beginningObject = getDoc().getParser().readInteger(randomAccess, false);
// followed by white space
int c = randomAccess.read();
if (c == -1) {
return;
}
if (c != 32) {
COSLoadWarning pwarn = new COSLoadWarning(PDFParser.C_WARN_SINGLESPACE);
pwarn.setHint(Long.valueOf(randomAccess.getOffset()));
getParser().handleWarning(pwarn);
}
c = randomAccess.read();
if (c == -1) {
return;
}
randomAccess.seekBy(-1);
if (!PDFParser.isDigit(c)) {
COSLoadWarning pwarn = new COSLoadWarning(PDFParser.C_WARN_SINGLESPACE);
pwarn.setHint(Long.valueOf(randomAccess.getOffset()));
getParser().handleWarning(pwarn);
}
// read entry count
int numEntries = getDoc().getParser().readInteger(randomAccess, true);
// read spaces
getDoc().getParser().readSpaces(randomAccess);
byte[] buffer = new byte[20];
STXRefEntry entry;
for (int i = 0; i < numEntries; i++) {
// read complete entry
// todo 1 @mit this may be complete garbage
c = randomAccess.read(buffer);
if (c == -1) {
// must fail anyway
return;
}
entry = parseEntry(beginningObject + i, buffer);
xRef.addEntry(entry);
}
}
}