/*
* $Id: PdfSmartCopy.java 4242 2010-01-02 23:22:20Z xlv $
*
* This file is part of the iText project.
* Copyright (c) 1998-2009 1T3XT BVBA
* Authors: Bruno Lowagie, Paulo Soares, 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 1T3XT,
* 1T3XT 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,
* you 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: sales@itextpdf.com
*/
package com.itextpdf.text.pdf;
import java.io.IOException;
import java.io.OutputStream;
import java.security.MessageDigest;
import java.util.Arrays;
import java.util.HashMap;
import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.ExceptionConverter;
/**
* PdfSmartCopy has the same functionality as PdfCopy,
* but when resources (such as fonts, images,...) are
* encountered, a reference to these resources is saved
* in a cache, so that they can be reused.
* This requires more memory, but reduces the file size
* of the resulting PDF document.
*/
public class PdfSmartCopy extends PdfCopy {
/** the cache with the streams and references. */
private HashMap<ByteStore, PdfIndirectReference> streamMap = null;
/** Creates a PdfSmartCopy instance. */
public PdfSmartCopy(Document document, OutputStream os) throws DocumentException {
super(document, os);
this.streamMap = new HashMap<ByteStore, PdfIndirectReference>();
}
/**
* Translate a PRIndirectReference to a PdfIndirectReference
* In addition, translates the object numbers, and copies the
* referenced object to the output file if it wasn't available
* in the cache yet. If it's in the cache, the reference to
* the already used stream is returned.
*
* NB: PRIndirectReferences (and PRIndirectObjects) really need to know what
* file they came from, because each file has its own namespace. The translation
* we do from their namespace to ours is *at best* heuristic, and guaranteed to
* fail under some circumstances.
*/
@Override
protected PdfIndirectReference copyIndirect(PRIndirectReference in) throws IOException, BadPdfFormatException {
PdfObject srcObj = PdfReader.getPdfObjectRelease(in);
ByteStore streamKey = null;
boolean validStream = false;
if (srcObj.isStream()) {
streamKey = new ByteStore((PRStream)srcObj);
validStream = true;
PdfIndirectReference streamRef = streamMap.get(streamKey);
if (streamRef != null) {
return streamRef;
}
}
PdfIndirectReference theRef;
RefKey key = new RefKey(in);
IndirectReferences iRef = indirects.get(key);
if (iRef != null) {
theRef = iRef.getRef();
if (iRef.getCopied()) {
return theRef;
}
} else {
theRef = body.getPdfIndirectReference();
iRef = new IndirectReferences(theRef);
indirects.put(key, iRef);
}
if (srcObj.isDictionary()) {
PdfObject type = PdfReader.getPdfObjectRelease(((PdfDictionary)srcObj).get(PdfName.TYPE));
if (type != null && PdfName.PAGE.equals(type)) {
return theRef;
}
}
iRef.setCopied();
if (validStream) {
streamMap.put(streamKey, theRef);
}
PdfObject obj = copyObject(srcObj);
addToBody(obj, theRef);
return theRef;
}
static class ByteStore {
private byte[] b;
private int hash;
private MessageDigest md5;
private void serObject(PdfObject obj, int level, ByteBuffer bb) throws IOException {
if (level <= 0)
return;
if (obj == null) {
bb.append("$Lnull");
return;
}
obj = PdfReader.getPdfObject(obj);
if (obj.isStream()) {
bb.append("$B");
serDic((PdfDictionary)obj, level - 1, bb);
if (level > 0) {
md5.reset();
bb.append(md5.digest(PdfReader.getStreamBytesRaw((PRStream)obj)));
}
}
else if (obj.isDictionary()) {
serDic((PdfDictionary)obj, level - 1, bb);
}
else if (obj.isArray()) {
serArray((PdfArray)obj, level - 1, bb);
}
else if (obj.isString()) {
bb.append("$S").append(obj.toString());
}
else if (obj.isName()) {
bb.append("$N").append(obj.toString());
}
else
bb.append("$L").append(obj.toString());
}
private void serDic(PdfDictionary dic, int level, ByteBuffer bb) throws IOException {
bb.append("$D");
if (level <= 0)
return;
Object[] keys = dic.getKeys().toArray();
Arrays.sort(keys);
for (int k = 0; k < keys.length; ++k) {
serObject((PdfObject)keys[k], level, bb);
serObject(dic.get((PdfName)keys[k]), level, bb);
}
}
private void serArray(PdfArray array, int level, ByteBuffer bb) throws IOException {
bb.append("$A");
if (level <= 0)
return;
for (int k = 0; k < array.size(); ++k) {
serObject(array.getPdfObject(k), level, bb);
}
}
ByteStore(PRStream str) throws IOException {
try {
md5 = MessageDigest.getInstance("MD5");
}
catch (Exception e) {
throw new ExceptionConverter(e);
}
ByteBuffer bb = new ByteBuffer();
int level = 100;
serObject(str, level, bb);
this.b = bb.toByteArray();
md5 = null;
}
@Override
public boolean equals(Object obj) {
if (!(obj instanceof ByteStore))
return false;
if (hashCode() != obj.hashCode())
return false;
return Arrays.equals(b, ((ByteStore)obj).b);
}
@Override
public int hashCode() {
if (hash == 0) {
int len = b.length;
for (int k = 0; k < len; ++k) {
hash = hash * 31 + (b[k] & 0xff);
}
}
return hash;
}
}
}