325 lines
12 KiB
C#
325 lines
12 KiB
C#
using System;
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using System.IO;
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using System.Collections;
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using System.util.zlib;
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/*
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* $Id: PdfStream.cs,v 1.12 2008/05/13 11:25:23 psoares33 Exp $
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*
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*
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* Copyright 1999, 2000, 2001, 2002 Bruno Lowagie
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*
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* The contents of this file are subject to the Mozilla Public License Version 1.1
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* (the "License"); you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the License.
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*
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* The Original Code is 'iText, a free JAVA-PDF library'.
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*
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* The Initial Developer of the Original Code is Bruno Lowagie. Portions created by
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* the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie.
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* All Rights Reserved.
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* Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer
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* are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved.
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*
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* Contributor(s): all the names of the contributors are added in the source code
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* where applicable.
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*
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* Alternatively, the contents of this file may be used under the terms of the
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* LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the
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* provisions of LGPL are applicable instead of those above. If you wish to
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* allow use of your version of this file only under the terms of the LGPL
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* License and not to allow others to use your version of this file under
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* the MPL, indicate your decision by deleting the provisions above and
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* replace them with the notice and other provisions required by the LGPL.
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* If you do not delete the provisions above, a recipient may use your version
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* of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE.
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*
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* This library is free software; you can redistribute it and/or modify it
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* under the terms of the MPL as stated above or under the terms of the GNU
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* Library General Public License as published by the Free Software Foundation;
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* either version 2 of the License, or any later version.
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*
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* This library is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU Library general Public License for more
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* details.
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*
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* If you didn't download this code from the following link, you should check if
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* you aren't using an obsolete version:
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* http://www.lowagie.com/iText/
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*/
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namespace iTextSharp.text.pdf {
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/**
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* <CODE>PdfStream</CODE> is the Pdf stream object.
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* <P>
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* A stream, like a string, is a sequence of characters. However, an application can
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* read a small portion of a stream at a time, while a string must be read in its entirety.
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* For this reason, objects with potentially large amounts of data, such as images and
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* page descriptions, are represented as streams.<BR>
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* A stream consists of a dictionary that describes a sequence of characters, followed by
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* the keyword <B>stream</B>, followed by zero or more lines of characters, followed by
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* the keyword <B>endstream</B>.<BR>
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* All streams must be <CODE>PdfIndirectObject</CODE>s. The stream dictionary must be a direct
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* object. The keyword <B>stream</B> that follows the stream dictionary should be followed by
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* a carriage return and linefeed or just a linefeed.<BR>
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* Remark: In this version only the FLATEDECODE-filter is supported.<BR>
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* This object is described in the 'Portable Document Format Reference Manual version 1.3'
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* section 4.8 (page 41-53).<BR>
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*
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* @see PdfObject
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* @see PdfDictionary
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*/
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public class PdfStream : PdfDictionary {
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// membervariables
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/** is the stream compressed? */
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protected bool compressed = false;
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protected MemoryStream streamBytes = null;
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protected Stream inputStream;
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protected PdfIndirectReference iref;
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protected int inputStreamLength = -1;
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protected PdfWriter writer;
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protected int rawLength;
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internal static byte[] STARTSTREAM = DocWriter.GetISOBytes("stream\n");
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internal static byte[] ENDSTREAM = DocWriter.GetISOBytes("\nendstream");
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internal static int SIZESTREAM = STARTSTREAM.Length + ENDSTREAM.Length;
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// constructors
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/**
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* Constructs a <CODE>PdfStream</CODE>-object.
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*
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* @param bytes content of the new <CODE>PdfObject</CODE> as an array of <CODE>byte</CODE>.
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*/
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public PdfStream(byte[] bytes) : base() {
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type = STREAM;
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this.bytes = bytes;
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rawLength = bytes.Length;
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Put(PdfName.LENGTH, new PdfNumber(bytes.Length));
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}
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/**
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* Creates an efficient stream. No temporary array is ever created. The <CODE>InputStream</CODE>
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* is totally consumed but is not closed. The general usage is:
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* <p>
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* <pre>
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* InputStream in = ...;
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* PdfStream stream = new PdfStream(in, writer);
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* stream.FlateCompress();
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* writer.AddToBody(stream);
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* stream.WriteLength();
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* in.Close();
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* </pre>
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* @param inputStream the data to write to this stream
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* @param writer the <CODE>PdfWriter</CODE> for this stream
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*/
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public PdfStream(Stream inputStream, PdfWriter writer) {
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type = STREAM;
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this.inputStream = inputStream;
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this.writer = writer;
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iref = writer.PdfIndirectReference;
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Put(PdfName.LENGTH, iref);
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}
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/**
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* Constructs a <CODE>PdfStream</CODE>-object.
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*/
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protected PdfStream() : base() {
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type = STREAM;
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}
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// methods overriding some methods of PdfObject
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/**
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* Writes the stream length to the <CODE>PdfWriter</CODE>.
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* <p>
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* This method must be called and can only be called if the contructor {@link #PdfStream(InputStream,PdfWriter)}
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* is used to create the stream.
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* @throws IOException on error
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* @see #PdfStream(InputStream,PdfWriter)
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*/
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public void WriteLength() {
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if (inputStream == null)
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throw new PdfException("WriteLength() can only be called in a contructed PdfStream(InputStream,PdfWriter).");
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if (inputStreamLength == -1)
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throw new PdfException("WriteLength() can only be called after output of the stream body.");
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writer.AddToBody(new PdfNumber(inputStreamLength), iref, false);
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}
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public int RawLength {
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get {
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return rawLength;
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}
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}
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// methods
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/**
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* Compresses the stream.
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*
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* @throws PdfException if a filter is allready defined
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*/
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public void FlateCompress() {
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if (!Document.Compress)
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return;
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// check if the flateCompress-method has allready been
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if (compressed) {
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return;
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}
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if (inputStream != null) {
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compressed = true;
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return;
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}
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// check if a filter allready exists
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PdfObject filter = PdfReader.GetPdfObject(Get(PdfName.FILTER));
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if (filter != null) {
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if (filter.IsName()) {
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if (PdfName.FLATEDECODE.Equals(filter))
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return;
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}
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else if (filter.IsArray()) {
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if (((PdfArray) filter).Contains(PdfName.FLATEDECODE))
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return;
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}
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else {
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throw new PdfException("Stream could not be compressed: filter is not a name or array.");
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}
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}
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// compress
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MemoryStream stream = new MemoryStream();
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ZDeflaterOutputStream zip = new ZDeflaterOutputStream(stream);
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if (streamBytes != null)
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streamBytes.WriteTo(zip);
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else
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zip.Write(bytes, 0, bytes.Length);
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//zip.Close();
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zip.Finish();
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// update the object
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streamBytes = stream;
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bytes = null;
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Put(PdfName.LENGTH, new PdfNumber(streamBytes.Length));
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if (filter == null) {
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Put(PdfName.FILTER, PdfName.FLATEDECODE);
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}
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else {
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PdfArray filters = new PdfArray(filter);
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filters.Add(PdfName.FLATEDECODE);
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Put(PdfName.FILTER, filters);
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}
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compressed = true;
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}
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protected virtual void SuperToPdf(PdfWriter writer, Stream os) {
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base.ToPdf(writer, os);
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}
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public override void ToPdf(PdfWriter writer, Stream os) {
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if (inputStream != null && compressed)
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Put(PdfName.FILTER, PdfName.FLATEDECODE);
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PdfEncryption crypto = null;
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if (writer != null)
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crypto = writer.Encryption;
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if (crypto != null) {
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PdfObject filter = Get(PdfName.FILTER);
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if (filter != null) {
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if (PdfName.CRYPT.Equals(filter))
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crypto = null;
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else if (filter.IsArray()) {
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ArrayList af = ((PdfArray)filter).ArrayList;
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if (af.Count > 0 && PdfName.CRYPT.Equals(af[0]))
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crypto = null;
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}
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}
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}
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PdfObject nn = Get(PdfName.LENGTH);
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if (crypto != null && nn != null && nn.IsNumber()) {
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int sz = ((PdfNumber)nn).IntValue;
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Put(PdfName.LENGTH, new PdfNumber(crypto.CalculateStreamSize(sz)));
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SuperToPdf(writer, os);
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Put(PdfName.LENGTH, nn);
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}
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else
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SuperToPdf(writer, os);
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os.Write(STARTSTREAM, 0, STARTSTREAM.Length);
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if (inputStream != null) {
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rawLength = 0;
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ZDeflaterOutputStream def = null;
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OutputStreamCounter osc = new OutputStreamCounter(os);
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OutputStreamEncryption ose = null;
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Stream fout = osc;
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if (crypto != null)
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fout = ose = crypto.GetEncryptionStream(fout);
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if (compressed)
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fout = def = new ZDeflaterOutputStream(fout);
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byte[] buf = new byte[4192];
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while (true) {
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int n = inputStream.Read(buf, 0, buf.Length);
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if (n <= 0)
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break;
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fout.Write(buf, 0, n);
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rawLength += n;
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}
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if (def != null)
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def.Finish();
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if (ose != null)
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ose.Finish();
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inputStreamLength = osc.Counter;
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}
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else {
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if (crypto == null) {
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if (streamBytes != null)
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streamBytes.WriteTo(os);
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else
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os.Write(bytes, 0, bytes.Length);
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}
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else {
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byte[] b;
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if (streamBytes != null) {
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b = crypto.EncryptByteArray(streamBytes.ToArray());
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}
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else {
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b = crypto.EncryptByteArray(bytes);
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}
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os.Write(b, 0, b.Length);
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}
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}
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os.Write(ENDSTREAM, 0, ENDSTREAM.Length);
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}
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/**
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* Writes the data content to an <CODE>Stream</CODE>.
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* @param os the destination to write to
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* @throws IOException on error
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*/
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public void WriteContent(Stream os) {
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if (streamBytes != null)
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streamBytes.WriteTo(os);
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else if (bytes != null)
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os.Write(bytes, 0, bytes.Length);
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}
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/**
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* @see com.lowagie.text.pdf.PdfObject#toString()
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*/
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public override String ToString() {
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if (Get(PdfName.TYPE) == null) return "Stream";
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return "Stream of type: " + Get(PdfName.TYPE);
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}
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}
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}
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