/*
 *
 * $Id: PDFXref.java,v 1.2 2007/08/26 18:56:35 gil1 Exp $
 *
 * $Date: 2007/08/26 18:56:35 $
 *
 * 
 *
 * 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
 * 
 */
package gnu.jpdf;

/**
 * <p>
 * This class is used to hold the xref information in the PDF Trailer block.</p>
 *
 * <p>
 * Basically, each object has an id, and an offset in the end file.</p>
 *
 * <p>
 * See the Adobe PDF Manual for more information. This class will normally not
 * be used directly by a developer</p>
 *
 * @author Peter T. Mount
 * @author Eric Z. Beard, ericzbeard@hotmail.com
 * @version $Revision: 1.2 $, $Date: 2007/08/26 18:56:35 $
 *
 */
public class PDFXref {

    /*
   * NOTE: Originally an inner class in PDF.java (now PDFDocument) written 
   * by Peter Mount for uk.org.retep.pdf
     */
    /**
     * The id of a PDF Object
     */
    public int id;

    /**
     * The offset within the PDF file
     */
    public int offset;

    /**
     * The generation of the object, usually 0
     */
    public int generation;

    /**
     * Creates a crossreference for a PDF Object
     *
     * @param id The object's ID
     * @param offset The object's position in the file
     */
    public PDFXref(int id, int offset) {
        this(id, offset, 0);
    }

    /**
     * Creates a crossreference for a PDF Object
     *
     * @param id The object's ID
     * @param offset The object's position in the file
     * @param generation The object's generation, usually 0
     */
    public PDFXref(int id, int offset, int generation) {
        this.id = id;
        this.offset = offset;
        this.generation = generation;
    }

    /**
     * @return The xref in the format of the xref section in the PDF file
     */
    @Override
    public String toString() {
        String of = Integer.toString(offset);
        String ge = Integer.toString(generation);
        String rs = "0000000000".substring(0, 10 - of.length())
                + of
                + " "
                + "00000".substring(0, 5 - ge.length()) + ge;
        if (generation == 65535) {
            return rs + " f ";
        }
        return rs + " n ";
    }

} // end class PDFXref