coswriter.java

非常有用的操作pdf文件的java源码

/**
 * Copyright (c) 2003-2006, www.pdfbox.org
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of pdfbox; 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 REGENTS 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.
 *
 * http://www.pdfbox.org
 *
 */
package org.pdfbox.pdfwriter;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;

import org.pdfbox.cos.COSArray;
import org.pdfbox.cos.COSBase;
import org.pdfbox.cos.COSBoolean;
import org.pdfbox.cos.COSDictionary;
import org.pdfbox.cos.COSDocument;
import org.pdfbox.cos.COSFloat;
import org.pdfbox.cos.COSInteger;
import org.pdfbox.cos.COSName;
import org.pdfbox.cos.COSNull;
import org.pdfbox.cos.COSObject;
import org.pdfbox.cos.COSStream;
import org.pdfbox.cos.COSString;
import org.pdfbox.cos.ICOSVisitor;
import org.pdfbox.exceptions.COSVisitorException;
import org.pdfbox.exceptions.CryptographyException;
import org.pdfbox.pdmodel.PDDocument;
import org.pdfbox.pdmodel.encryption.SecurityHandler;
import org.pdfbox.persistence.util.COSObjectKey;

/**
 * this class acts on a in-memory representation of a pdf document.
 *
 * todo no support for incremental updates
 * todo single xref section only
 * todo no linearization
 *
 * @author Michael Traut
 * @author <a href="mailto:[e-mail]">Ben Litchfield</a>
 * @version $Revision: 1.36 $
 */
public class COSWriter implements ICOSVisitor
{
    /**
     * The dictionary open token.
     */
    public static final byte[] DICT_OPEN = "<<".getBytes();
    /**
     * The dictionary close token.
     */
    public static final byte[] DICT_CLOSE = ">>".getBytes();
    /**
     * space character.
     */
    public static final byte[] SPACE = " ".getBytes();
    /**
     * The start to a PDF comment.
     */
    public static final byte[] COMMENT = "%".getBytes();

    /**
     * The output version of the PDF.
     */
    public static final byte[] VERSION = "PDF-1.4".getBytes();
    /**
     * Garbage bytes used to create the PDF header.
     */
    public static final byte[] GARBAGE = new byte[] {(byte)0xf6, (byte)0xe4, (byte)0xfc, (byte)0xdf};
    /**
     * The EOF constant.
     */
    public static final byte[] EOF = "%%EOF".getBytes();
    // pdf tokens

    /**
     * The reference token.
     */
    public static final byte[] REFERENCE = "R".getBytes();
    /**
     * The XREF token.
     */
    public static final byte[] XREF = "xref".getBytes();
    /**
     * The xref free token.
     */
    public static final byte[] XREF_FREE = "f".getBytes();
    /**
     * The xref used token.
     */
    public static final byte[] XREF_USED = "n".getBytes();
    /**
     * The trailer token.
     */
    public static final byte[] TRAILER = "trailer".getBytes();
    /**
     * The start xref token.
     */
    public static final byte[] STARTXREF = "startxref".getBytes();
    /**
     * The starting object token.
     */
    public static final byte[] OBJ = "obj".getBytes();
    /**
     * The end object token.
     */
    public static final byte[] ENDOBJ = "endobj".getBytes();
    /**
     * The array open token.
     */
    public static final byte[] ARRAY_OPEN = "[".getBytes();
    /**
     * The array close token.
     */
    public static final byte[] ARRAY_CLOSE = "]".getBytes();
    /**
     * The open stream token.
     */
    public static final byte[] STREAM = "stream".getBytes();
    /**
     * The close stream token.
     */
    public static final byte[] ENDSTREAM = "endstream".getBytes();

    private NumberFormat formatXrefOffset = new DecimalFormat("0000000000");
    /**
     * The decimal format for the xref object generation number data.
     */
    private NumberFormat formatXrefGeneration = new DecimalFormat("00000");

    private NumberFormat formatDecimal = NumberFormat.getNumberInstance( Locale.US );

    // the stream where we create the pdf output
    private OutputStream output;
    // the stream used to write standard cos data
    private COSStandardOutputStream standardOutput;

    // the start position of the x ref section
    private long startxref = 0;

    // the current object number
    private long number = 0;

    // maps the object to the keys generated in the writer
    // these are used for indirect refrences in other objects
    //A hashtable is used on purpose over a hashmap 
    //so that null entries will not get added.
    private Map objectKeys = new Hashtable();

    // the list of x ref entries to be made so far
    private List xRefEntries = new ArrayList();

    //A list of objects to write.
    private List objectsToWrite = new ArrayList();

    //a list of objects already written
    private Set writtenObjects = new HashSet();
    //An 'actual' is any COSBase that is not a COSObject.
    //need to keep a list of the actuals that are added
    //as well as the objects because there is a problem
    //when adding a COSObject and then later adding
    //the actual for that object, so we will track
    //actuals separately.
    private Set actualsAdded = new HashSet();
    
    private COSObjectKey currentObjectKey = null;
   
    private PDDocument document = null;
    
    private boolean willEncrypt = false;

    /**
     * COSWriter constructor comment.
     *
     * @param os The wrapped output stream.
     */
    public COSWriter(OutputStream os)
    {
        super();
        setOutput(os);
        setStandardOutput(new COSStandardOutputStream(getOutput()));
        formatDecimal.setMaximumFractionDigits( 10 );
        formatDecimal.setGroupingUsed( false );
    }
    /**
     * add an entry in the x ref table for later dump.
     *
     * @param entry The new entry to add.
     */
    protected void addXRefEntry(COSWriterXRefEntry entry)
    {
        getXRefEntries().add(entry);
    }

    /**
     * This will close the stream.
     *
     * @throws IOException If the underlying stream throws an exception.
     */
    public void close() throws IOException
    {
        if (getStandardOutput() != null)
        {
            getStandardOutput().close();
        }
        if (getOutput() != null)
        {
            getOutput().close();
        }
    }

    /**
     * This will get the current object number.
     *
     * @return The current object number.
     */
    protected long getNumber()
    {
        return number;
    }

    /**
     * This will get all available object keys.
     *
     * @return A map of all object keys.
     */
    public java.util.Map getObjectKeys()
    {
        return objectKeys;
    }

    /**
     * This will get the output stream.
     *
     * @return The output stream.
     */
    protected java.io.OutputStream getOutput()
    {
        return output;
    }

    /**
     * This will get the standard output stream.
     *
     * @return The standard output stream.
     */
    protected COSStandardOutputStream getStandardOutput()
    {
        return standardOutput;
    }

    /**
     * This will get the current start xref.
     *
     * @return The current start xref.
     */
    protected long getStartxref()
    {
        return startxref;
    }
    /**
     * This will get the xref entries.
     *
     * @return All available xref entries.
     */
    protected java.util.List getXRefEntries()
    {
        return xRefEntries;
    }

    /**
     * This will set the current object number.
     *
     * @param newNumber The new object number.
     */
    protected void setNumber(long newNumber)
    {
        number = newNumber;
    }

    /**
     * This will set the output stream.
     *
     * @param newOutput The new output stream.
     */
    private void setOutput( OutputStream newOutput )
    {
        output = newOutput;
    }

    /**
     * This will set the standard output stream.
     *
     * @param newStandardOutput The new standard output stream.
     */
    private void setStandardOutput(COSStandardOutputStream newStandardOutput)
    {
        standardOutput = newStandardOutput;
    }

    /**
     * This will set the start xref.
     *
     * @param newStartxref The new start xref attribute.
     */
    protected void setStartxref(long newStartxref)
    {
        startxref = newStartxref;
    }

    /**
     * This will write the body of the document.
     *
     * @param doc The document to write the body for.
     *
     * @throws IOException If there is an error writing the data.
     * @throws COSVisitorException If there is an error generating the data.
     */
    protected void doWriteBody(COSDocument doc) throws IOException, COSVisitorException
    {
        COSDictionary trailer = doc.getTrailer();
        COSDictionary root = (COSDictionary)trailer.getDictionaryObject( COSName.ROOT );
        COSDictionary info = (COSDictionary)trailer.getDictionaryObject( COSName.getPDFName( "Info" ) );
        COSDictionary encrypt = (COSDictionary)trailer.getDictionaryObject( COSName.getPDFName( "Encrypt" ) );
        if( root != null )