jeremias 2003/03/27 02:14:24 Added: src/java/org/apache/fop/pdf AbstractPDFStream.java Log: Abstract base class for all PDF streams. It supports writing stream on-the-fly (Length dict entry is a forward reference). This can be disabled in PDFDocument, the old method still works. Revision Changes Path 1.1 xml-fop/src/java/org/apache/fop/pdf/AbstractPDFStream.java Index: AbstractPDFStream.java =================================================================== /* * $Id$ * ============================================================================ * The Apache Software License, Version 1.1 * ============================================================================ * * Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved. * * Redistribution and use in source and binary forms, with or without modifica- * tion, 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. The end-user documentation included with the redistribution, if any, must * include the following acknowledgment: "This product includes software * developed by the Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowledgment may appear in the software itself, if * and wherever such third-party acknowledgments normally appear. * * 4. The names "FOP" and "Apache Software Foundation" must not be used to * endorse or promote products derived from this software without prior * written permission. For written permission, please contact * [EMAIL PROTECTED] * * 5. Products derived from this software may not be called "Apache", nor may * "Apache" appear in their name, without prior written permission of the * Apache Software Foundation. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 * APACHE SOFTWARE FOUNDATION OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLU- * DING, 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. * ============================================================================ * * This software consists of voluntary contributions made by many individuals * on behalf of the Apache Software Foundation and was originally created by * James Tauber <[EMAIL PROTECTED]>. For more information on the Apache * Software Foundation, please see <http://www.apache.org/>. */ package org.apache.fop.pdf; import java.io.IOException; import java.io.OutputStream; import org.apache.commons.io.output.CountingOutputStream; import org.apache.fop.util.CloseBlockerOutputStream; /** * This is an abstract base class for PDF streams. */ public abstract class AbstractPDFStream extends PDFObject { /** The filters that should be applied */ private PDFFilterList filters; /** * Constructor for AbstractPDFStream. */ public AbstractPDFStream() { super(); } /** * Sets up the default filters for this stream if they haven't been set * from outside. */ protected void setupFilterList() { if (!getFilterList().isInitialized()) { getFilterList().addDefaultFilters( getDocumentSafely().getFilterMap(), PDFFilterList.DEFAULT_FILTER); } prepareImplicitFilters(); getDocument().applyEncryption(this); } /** * Returns the associated filter list. * @return the filter list */ public PDFFilterList getFilterList() { if (this.filters == null) { if (getDocument() == null) { this.filters = new PDFFilterList(); } else { this.filters = new PDFFilterList(getDocument().isEncryptionActive()); //this.filters = new PDFFilterList(false); } } return this.filters; } /** * Returns a value that hints at the size of the encoded stream. This is * used to optimize buffer allocation so fewer buffer reallocations are * necessary. * @return an estimated size (0 if no hint can be given) * @throws IOException in case of an I/O problem */ protected abstract int getSizeHint() throws IOException; /** * Sends the raw stream data to the target OutputStream. * @param out OutputStream to write to * @throws IOException In case of an I/O problem */ protected abstract void outputRawStreamData(OutputStream out) throws IOException; /** * Output just the stream data enclosed by stream/endstream markers * @param encodedStream already encoded/filtered stream to write * @param out OutputStream to write to * @return int number of bytes written * @throws IOException in case of an I/O problem */ protected int outputStreamData(StreamCache encodedStream, OutputStream out) throws IOException { int length = 0; byte[] p = encode("stream\n"); out.write(p); length += p.length; encodedStream.outputContents(out); length += encodedStream.getSize(); p = encode("\nendstream"); out.write(p); length += p.length; return length; } /** * Encodes the raw data stream for output to a PDF file. * @return the encoded stream * @throws IOException in case of an I/O problem */ protected StreamCache encodeStream() throws IOException { //Allocate a temporary buffer to find out the size of the encoded stream final StreamCache encodedStream = StreamCacheFactory.getInstance(). createStreamCache(getSizeHint()); OutputStream filteredOutput = getFilterList().applyFilters(encodedStream.getOutputStream()); outputRawStreamData(filteredOutput); filteredOutput.flush(); filteredOutput.close(); return encodedStream; } /** * Encodes and writes a stream directly to an OutputStream. The length of * the stream, in this case, is set on a PDFNumber object that has to be * prepared beforehand. * @param out OutputStream to write to * @param refLength PDFNumber object to receive the stream length * @return number of bytes written (header and trailer included) * @throws IOException in case of an I/O problem */ protected int encodeAndWriteStream(OutputStream out, PDFNumber refLength) throws IOException { int bytesWritten = 0; //Stream header byte[] buf = encode("stream\n"); out.write(buf); bytesWritten += buf.length; //Stream contents CloseBlockerOutputStream cbout = new CloseBlockerOutputStream(out); CountingOutputStream cout = new CountingOutputStream(cbout); OutputStream filteredOutput = getFilterList().applyFilters(cout); outputRawStreamData(filteredOutput); filteredOutput.close(); refLength.setNumber(new Integer(cout.getCount())); bytesWritten += cout.getCount(); //Stream trailer buf = encode("\nendstream"); out.write(buf); bytesWritten += buf.length; return bytesWritten; } /** * Overload the base object method so we don't have to copy * byte arrays around so much * @see org.apache.fop.pdf.PDFObject#output(OutputStream) */ protected int output(OutputStream stream) throws IOException { int length = 0; setupFilterList(); StreamCache encodedStream = null; PDFNumber refLength = null; final String lengthEntry; if (getDocument().isEncodingOnTheFly()) { refLength = new PDFNumber(); getDocumentSafely().registerObject(refLength); lengthEntry = refLength.referencePDF(); } else { encodedStream = encodeStream(); lengthEntry = Integer.toString(encodedStream.getSize() + 1); } String filterEntry = getFilterList().buildFilterDictEntries(); byte[] p = encode(buildStreamDict(lengthEntry)); stream.write(p); length += p.length; //Send encoded stream to target OutputStream if (encodedStream == null) { int bytesWritten = encodeAndWriteStream(stream, refLength); length += bytesWritten; } else { length += outputStreamData(encodedStream, stream); encodedStream.clear(); //Encoded stream can now be discarded } p = encode("\nendobj\n"); stream.write(p); length += p.length; return length; } /** * Constructs the dictionary for the stream. Override this method if you * need additional entries. * @param lengthEntry value for the /Length entry * @return the newly constructed dictionary */ protected String buildStreamDict(String lengthEntry) { final String filterEntry = getFilterList().buildFilterDictEntries(); return (getObjectID() + "<< /Length " + lengthEntry + "\n" + filterEntry + "\n>>\n"); } /** * Prepares implicit filters (such as the DCTFilter for JPEG images). You * must make sure that the appropriate filters are in the filter list at * the right places. */ protected void prepareImplicitFilters() { //nop: No default implicit filters } }
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