PdfPages.java

/*
 * $Id: PdfPages.java 4065 2009-09-16 23:09:11Z psoares33 $
 *
 * Copyright 1999, 2000, 2001, 2002 Bruno Lowagie
 *
 * The contents of this file are subject to the Mozilla Public License Version 1.1
 * (the "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the License.
 *
 * The Original Code is 'iText, a free JAVA-PDF library'.
 *
 * The Initial Developer of the Original Code is Bruno Lowagie. Portions created by
 * the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie.
 * All Rights Reserved.
 * Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer
 * are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved.
 *
 * Contributor(s): all the names of the contributors are added in the source code
 * where applicable.
 *
 * Alternatively, the contents of this file may be used under the terms of the
 * LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the
 * provisions of LGPL are applicable instead of those above.  If you wish to
 * allow use of your version of this file only under the terms of the LGPL
 * License and not to allow others to use your version of this file under
 * the MPL, indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by the LGPL.
 * If you do not delete the provisions above, a recipient may use your version
 * of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE.
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the MPL as stated above or under the terms of the GNU
 * Library General Public License as published by the Free Software Foundation;
 * either version 2 of the License, or 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 Library general Public License for more
 * details.
 *
 * If you didn't download this code from the following link, you should check if
 * you aren't using an obsolete version:
 * https://github.com/LibrePDF/OpenPDF
 */

package org.openpdf.text.pdf;

import org.openpdf.text.ExceptionConverter;
import org.openpdf.text.error_messages.MessageLocalization;
import java.io.IOException;
import java.util.ArrayList;

/**
 * <CODE>PdfPages</CODE> is the PDF Pages-object.
 * <p>
 * The Pages of a document are accessible through a tree of nodes known as the Pages tree. This tree defines the
 * ordering of the pages in the document.<BR> This object is described in the 'Portable Document Format Reference Manual
 * version 1.3' section 6.3 (page 71-73)
 *
 * @see PdfPage
 */

public class PdfPages {

    private final ArrayList<PdfIndirectReference> pages = new ArrayList<>();
    private final ArrayList<PdfIndirectReference> parents = new ArrayList<>();
    private final PdfWriter writer;
    private int leafSize = 10;
    private PdfIndirectReference topParent;

    // constructors

    /**
     * Constructs a <CODE>PdfPages</CODE>-object.
     */

    PdfPages(PdfWriter writer) {
        this.writer = writer;
    }

    void addPage(PdfDictionary page) {
        try {
            if ((pages.size() % leafSize) == 0) {
                parents.add(writer.getPdfIndirectReference());
            }
            PdfIndirectReference parent = parents.get(parents.size() - 1);
            page.put(PdfName.PARENT, parent);
            PdfIndirectReference current = writer.getCurrentPage();
            writer.addToBody(page, current);
            pages.add(current);
        } catch (Exception e) {
            throw new ExceptionConverter(e);
        }
    }

    // returns the top parent to include in the catalog
    PdfIndirectReference writePageTree() throws IOException {
        if (pages.isEmpty()) {
            throw new IOException(MessageLocalization.getComposedMessage("the.document.has.no.pages"));
        }
        int leaf = 1;
        ArrayList<PdfIndirectReference> tParents = parents;
        ArrayList<PdfIndirectReference> tPages = pages;
        ArrayList<PdfIndirectReference> nextParents = new ArrayList<>();
        while (true) {
            leaf *= leafSize;
            int stdCount = leafSize;
            int rightCount = tPages.size() % leafSize;
            if (rightCount == 0) {
                rightCount = leafSize;
            }
            for (int p = 0; p < tParents.size(); ++p) {
                int count;
                int thisLeaf = leaf;
                if (p == tParents.size() - 1) {
                    count = rightCount;
                    thisLeaf = pages.size() % leaf;
                    if (thisLeaf == 0) {
                        thisLeaf = leaf;
                    }
                } else {
                    count = stdCount;
                }
                PdfDictionary top = new PdfDictionary(PdfName.PAGES);
                top.put(PdfName.COUNT, new PdfNumber(thisLeaf));
                PdfArray kids = new PdfArray(tPages.subList(p * stdCount, p * stdCount + count));
                top.put(PdfName.KIDS, kids);
                if (tParents.size() > 1) {
                    if ((p % leafSize) == 0) {
                        nextParents.add(writer.getPdfIndirectReference());
                    }
                    top.put(PdfName.PARENT, nextParents.get(p / leafSize));
                }
                writer.addToBody(top, tParents.get(p));
            }
            if (tParents.size() == 1) {
                topParent = tParents.get(0);
                return topParent;
            }
            tPages = tParents;
            tParents = nextParents;
            nextParents = new ArrayList<>();
        }
    }

}