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iText Xtra, part of iText a Free Java-PDF library
/*
*
* This file is part of the iText (R) project.
Copyright (c) 1998-2017 iText Group NV
* Authors: Bruno Lowagie, et al.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License version 3
* as published by the Free Software Foundation with the addition of the
* following permission added to Section 15 as permitted in Section 7(a):
* FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
* ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
* OF THIRD PARTY RIGHTS
*
* This program 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 Affero General Public License for more details.
* You should have received a copy of the GNU Affero General Public License
* along with this program; if not, see http://www.gnu.org/licenses or write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA, 02110-1301 USA, or download the license from the following URL:
* http://itextpdf.com/terms-of-use/
*
* The interactive user interfaces in modified source and object code versions
* of this program must display Appropriate Legal Notices, as required under
* Section 5 of the GNU Affero General Public License.
*
* In accordance with Section 7(b) of the GNU Affero General Public License,
* a covered work must retain the producer line in every PDF that is created
* or manipulated using iText.
*
* You can be released from the requirements of the license by purchasing
* a commercial license. Buying such a license is mandatory as soon as you
* develop commercial activities involving the iText software without
* disclosing the source code of your own applications.
* These activities include: offering paid services to customers as an ASP,
* serving PDFs on the fly in a web application, shipping iText with a closed
* source product.
*
* For more information, please contact iText Software Corp. at this
* address: [email protected]
*/
package com.itextpdf.text.pdf.mc;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.error_messages.MessageLocalization;
import com.itextpdf.text.log.Logger;
import com.itextpdf.text.log.LoggerFactory;
import com.itextpdf.text.pdf.PdfArray;
import com.itextpdf.text.pdf.PdfDictionary;
import com.itextpdf.text.pdf.PdfIndirectReference;
import com.itextpdf.text.pdf.PdfName;
import com.itextpdf.text.pdf.PdfNumber;
import com.itextpdf.text.pdf.PdfNumberTree;
import com.itextpdf.text.pdf.PdfObject;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfWriter;
/**
* Creates a list of StructureItem objects extracted from the
* Structure Tree of a PDF document.
*/
public class StructureItems extends ArrayList {
/** The Logger instance */
protected final static Logger LOGGER = LoggerFactory.getLogger(StructureItems.class);
/** The StructTreeRoot dictionary */
protected PdfDictionary structTreeRoot;
/** The StructParents number tree values. */
protected HashMap parentTree;
/**
* Creates a list of StructuredItem objects.
* @param reader the reader holding the PDF to examine
*/
public StructureItems(PdfReader reader)
throws DocumentException {
super();
PdfDictionary catalog = reader.getCatalog();
structTreeRoot = catalog.getAsDict(PdfName.STRUCTTREEROOT);
if (structTreeRoot == null)
throw new DocumentException(MessageLocalization.getComposedMessage("can.t.read.document.structure"));
// Storing the parent tree
parentTree = PdfNumberTree.readTree(structTreeRoot.getAsDict(PdfName.PARENTTREE));
structTreeRoot.remove(PdfName.STRUCTPARENTS);
// Examining the StructTreeRoot
PdfObject object = structTreeRoot.getDirectObject(PdfName.K);
if (object == null)
return;
switch(object.type()) {
case PdfObject.DICTIONARY:
LOGGER.info("StructTreeRoot refers to dictionary");
processStructElems((PdfDictionary)object, structTreeRoot.getAsIndirectObject(PdfName.K));
break;
case PdfObject.ARRAY:
LOGGER.info("StructTreeRoot refers to array");
PdfArray array = (PdfArray) object;
for (int i = 0; i < array.size(); i++) {
processStructElems(array.getAsDict(i), array.getAsIndirectObject(i));
}
break;
}
}
/**
* Looks at a StructElem dictionary, and processes it.
* @param structElem the StructElem dictionary that needs to be examined
* @param ref the reference to the StructElem dictionary
* @throws DocumentException
*/
protected void processStructElems(PdfDictionary structElem, PdfIndirectReference ref) {
LOGGER.info(String.format("addStructureItems(%s, %s)", structElem, ref));
if (structElem == null)
return;
processStructElemKids(structElem, ref, structElem.getDirectObject(PdfName.K));
}
/**
* Processes the kids object of a StructElem dictionary.
* This kids object can be a number (MCID), another StructElem dictionary,
* an MCR dictionary, an OBJR dictionary, or an array of the above.
* @param structElem the StructElem dictionary
* @param ref the reference to the StructElem dictionary
* @param object the kids object
*/
protected void processStructElemKids(PdfDictionary structElem, PdfIndirectReference ref, PdfObject object) {
LOGGER.info(String.format("addStructureItem(%s, %s, %s)", structElem, ref, object));
if (object == null)
return;
StructureItem item;
switch(object.type()) {
case PdfObject.NUMBER:
item = new StructureMCID(structElem.getAsIndirectObject(PdfName.PG), (PdfNumber) object);
add(item);
LOGGER.info("Added " + item);
break;
case PdfObject.ARRAY:
PdfArray array = (PdfArray)object;
for (int i = 0; i < array.size(); i++) {
processStructElemKids(structElem, array.getAsIndirectObject(i), array.getDirectObject(i));
}
break;
case PdfObject.DICTIONARY:
PdfDictionary dict = (PdfDictionary)object;
if (dict.checkType(PdfName.MCR)) {
item = new StructureMCID(dict);
add(item);
LOGGER.info("Added " + item);
} else if (dict.checkType(PdfName.OBJR)) {
item = new StructureObject(structElem, ref, dict);
add(item);
LOGGER.info("Added " + item);
}
else {
processStructElems(dict, ref);
}
break;
}
}
/**
* Removes a StructParent from the parent tree.
* @param structParent the number to remove
*/
public void removeFromParentTree(PdfNumber structParent) {
parentTree.remove(structParent.intValue());
}
/**
* Creates a new MCID in the parent tree of the page
* and returns that new MCID so that it can be used
* in the content stream
* @param structParents the StructParents entry in the page dictionary
* @param ref the item for which we need a new MCID
* @return a new MCID
* @throws DocumentException
*/
public int processMCID(PdfNumber structParents, PdfIndirectReference ref)
throws DocumentException {
if (ref == null)
throw new DocumentException(MessageLocalization.getComposedMessage("can.t.read.document.structure"));
PdfObject object = parentTree.get(structParents.intValue());
PdfArray array = (PdfArray)PdfReader.getPdfObject(object);
int i = getNextMCID(structParents);
if (i < array.size()) {
array.set(i, ref);
return i;
}
array.add(ref);
return array.size() - 1;
}
/**
* Finds the next available MCID, which is either the lowest empty ID in
* the existing range, or the first available higher number.
* @param structParents the StructParents entry in the page dictionary
* @return the first available MCID
*/
public int getNextMCID(PdfNumber structParents) {
PdfObject object = parentTree.get(structParents.intValue());
PdfArray array = (PdfArray)PdfReader.getPdfObject(object);
for (int i = 0; i < array.size(); i++) {
if (array.getAsIndirectObject(i) == null) {
return i;
}
}
return array.size();
}
/**
* Writes the altered parent tree to a PdfWriter and updates the StructTreeRoot entry.
* @param writer The writer to which the StructParents have to be written
* @throws IOException
*/
public void writeParentTree(PdfWriter writer) throws IOException {
if (structTreeRoot == null)
return;
Integer numbers[] = new Integer[parentTree.size()];
numbers = parentTree.keySet().toArray(numbers);
Arrays.sort(numbers);
structTreeRoot.put(PdfName.PARENTTREENEXTKEY, new PdfNumber(numbers[numbers.length - 1] + 1));
structTreeRoot.put(PdfName.PARENTTREE, PdfNumberTree.writeTree(parentTree, writer));
}
/** Serial version UID */
private static final long serialVersionUID = -8247348202717165564L;
}