com.lowagie.text.pdf.PdfStream Maven / Gradle / Ivy
/*
* $Id: PdfStream.java,v 1.53 2004/12/14 15:15:59 blowagie Exp $
* $Name: $
*
* 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:
* http://www.lowagie.com/iText/
*/
package com.lowagie.text.pdf;
import java.io.ByteArrayOutputStream;
import java.io.OutputStream;
import java.io.InputStream;
import java.io.IOException;
import java.util.zip.DeflaterOutputStream;
import java.util.zip.Deflater;
import com.lowagie.text.Document;
import com.lowagie.text.DocWriter;
import com.lowagie.text.ExceptionConverter;
/**
* PdfStream is the Pdf stream object.
*
* A stream, like a string, is a sequence of characters. However, an application can
* read a small portion of a stream at a time, while a string must be read in its entirety.
* For this reason, objects with potentially large amounts of data, such as images and
* page descriptions, are represented as streams.
* A stream consists of a dictionary that describes a sequence of characters, followed by
* the keyword stream, followed by zero or more lines of characters, followed by
* the keyword endstream.
* All streams must be PdfIndirectObjects. The stream dictionary must be a direct
* object. The keyword stream that follows the stream dictionary should be followed by
* a carriage return and linefeed or just a linefeed.
* Remark: In this version only the FLATEDECODE-filter is supported.
* This object is described in the 'Portable Document Format Reference Manual version 1.3'
* section 4.8 (page 41-53).
*
* @see PdfObject
* @see PdfDictionary
*/
public class PdfStream extends PdfDictionary {
// membervariables
/** is the stream compressed? */
protected boolean compressed = false;
protected ByteArrayOutputStream streamBytes = null;
protected InputStream inputStream;
protected PdfIndirectReference ref;
protected int inputStreamLength = -1;
protected PdfWriter writer;
static final byte STARTSTREAM[] = DocWriter.getISOBytes("stream\n");
static final byte ENDSTREAM[] = DocWriter.getISOBytes("\nendstream");
static final int SIZESTREAM = STARTSTREAM.length + ENDSTREAM.length;
// constructors
/**
* Constructs a PdfStream-object.
*
* @param bytes content of the new PdfObject as an array of byte.
*/
public PdfStream(byte[] bytes) {
super();
type = STREAM;
this.bytes = bytes;
put(PdfName.LENGTH, new PdfNumber(bytes.length));
}
/**
* Creates an efficient stream. No temporary array is ever created. The InputStream
* is totally consumed but is not closed. The general usage is:
*
*
* InputStream in = ...;
* PdfStream stream = new PdfStream(in, writer);
* stream.flateCompress();
* writer.addToBody(stream);
* stream.writeLength();
* in.close();
*
* @param inputStream the data to write to this stream
* @param writer the PdfWriter for this stream
*/
public PdfStream(InputStream inputStream, PdfWriter writer) {
super();
type = STREAM;
this.inputStream = inputStream;
this.writer = writer;
ref = writer.getPdfIndirectReference();
put(PdfName.LENGTH, ref);
}
/**
* Constructs a PdfStream-object.
*/
protected PdfStream() {
super();
type = STREAM;
}
/**
* Writes the stream length to the PdfWriter.
*
* This method must be called and can only be called if the contructor {@link #PdfStream(InputStream,PdfWriter)}
* is used to create the stream.
* @throws IOException on error
* @see #PdfStream(InputStream,PdfWriter)
*/
public void writeLength() throws IOException {
if (inputStream == null)
throw new UnsupportedOperationException("writeLength() can only be called in a contructed PdfStream(InputStream,PdfWriter).");
if (inputStreamLength == -1)
throw new IOException("writeLength() can only be called after output of the stream body.");
writer.addToBody(new PdfNumber(inputStreamLength), ref, false);
}
/**
* Compresses the stream.
*/
public void flateCompress() {
if (!Document.compress)
return;
// check if the flateCompress-method has already been
if (compressed) {
return;
}
if (inputStream != null) {
compressed = true;
return;
}
// check if a filter already exists
PdfObject filter = get(PdfName.FILTER);
if (filter != null) {
if (filter.isName() && ((PdfName) filter).compareTo(PdfName.FLATEDECODE) == 0) {
return;
}
else if (filter.isArray() && ((PdfArray) filter).contains(PdfName.FLATEDECODE)) {
return;
}
else {
throw new RuntimeException("Stream could not be compressed: filter is not a name or array.");
}
}
try {
// compress
ByteArrayOutputStream stream = new ByteArrayOutputStream();
DeflaterOutputStream zip = new DeflaterOutputStream(stream);
if (streamBytes != null)
streamBytes.writeTo(zip);
else
zip.write(bytes);
zip.close();
// update the object
streamBytes = stream;
bytes = null;
put(PdfName.LENGTH, new PdfNumber(streamBytes.size()));
if (filter == null) {
put(PdfName.FILTER, PdfName.FLATEDECODE);
}
else {
PdfArray filters = new PdfArray(filter);
filters.add(PdfName.FLATEDECODE);
put(PdfName.FILTER, filters);
}
compressed = true;
}
catch(IOException ioe) {
throw new ExceptionConverter(ioe);
}
}
// public int getStreamLength(PdfWriter writer) {
// if (dicBytes == null)
// toPdf(writer);
// if (streamBytes != null)
// return streamBytes.size() + dicBytes.length + SIZESTREAM;
// else
// return bytes.length + dicBytes.length + SIZESTREAM;
// }
protected void superToPdf(PdfWriter writer, OutputStream os) throws IOException {
super.toPdf(writer, os);
}
public void toPdf(PdfWriter writer, OutputStream os) throws IOException {
if (inputStream != null && compressed)
put(PdfName.FILTER, PdfName.FLATEDECODE);
superToPdf(writer, os);
os.write(STARTSTREAM);
PdfEncryption crypto = null;
if (writer != null)
crypto = writer.getEncryption();
if (crypto != null)
crypto.prepareKey();
if (inputStream != null) {
DeflaterOutputStream def = null;
PdfEncryptionStream encs = null;
OutputStreamCounter osc = new OutputStreamCounter(os);
OutputStream fout = osc;
if (crypto != null)
fout = encs = new PdfEncryptionStream(fout, crypto);
if (compressed)
fout = def = new DeflaterOutputStream(fout, new Deflater(Deflater.BEST_COMPRESSION), 0x8000);
byte buf[] = new byte[0x10000];
while (true) {
int n = inputStream.read(buf);
if (n <= 0)
break;
fout.write(buf, 0, n);
}
if (def != null)
def.finish();
inputStreamLength = osc.getCounter();
}
else {
if (crypto == null) {
if (streamBytes != null)
streamBytes.writeTo(os);
else
os.write(bytes);
}
else {
byte b[];
if (streamBytes != null) {
b = streamBytes.toByteArray();
crypto.encryptRC4(b);
}
else {
b = new byte[bytes.length];
crypto.encryptRC4(bytes, b);
}
os.write(b);
}
}
os.write(ENDSTREAM);
}
}