123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301 |
- /*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (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.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
- /* $Id$ */
-
- package org.apache.fop.pdf;
-
- import java.io.IOException;
- import java.io.OutputStream;
- import java.util.Set;
-
- 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 {
-
- private final PDFDictionary dictionary;
-
- /** The filters that should be applied */
- private PDFFilterList filters;
-
- private boolean encodeOnTheFly;
-
- private PDFNumber refLength = new PDFNumber();
-
- protected AbstractPDFStream() {
- this(true);
- }
-
- protected AbstractPDFStream(PDFDictionary dictionary) {
- this(dictionary, true);
- }
-
- protected AbstractPDFStream(boolean encodeOnTheFly) {
- this(new PDFDictionary(), encodeOnTheFly);
- }
-
- protected AbstractPDFStream(PDFDictionary dictionary, boolean encodeOnTheFly) {
- this.dictionary = dictionary;
- dictionary.setParent(this);
- this.encodeOnTheFly = encodeOnTheFly;
- }
-
- protected final PDFDictionary getDictionary() {
- return dictionary;
- }
-
- public Object get(String key) {
- return dictionary.get(key);
- }
-
- /**
- * Puts the given object in the dictionary associated to this stream.
- *
- * @param key the key in the dictionary
- * @param value the value to store
- */
- public void put(String key, Object value) {
- dictionary.put(key, value);
- }
-
- /**
- * Sets up the default filters for this stream if they haven't been set
- * from outside.
- */
- protected void setupFilterList() {
- if (multipleFiltersAllowed() && !getFilterList().isInitialized()) {
- getFilterList().addDefaultFilters(
- getDocumentSafely().getFilterMap(),
- getDefaultFilterName());
- }
- prepareImplicitFilters();
- getDocument().applyEncryption(this);
- }
-
- /**
- * Returns the name of a suitable filter for this PDF object.
- *
- * @return the default filter
- * @see PDFFilterList
- */
- protected String getDefaultFilterName() {
- return PDFFilterList.DEFAULT_FILTER;
- }
-
- /**
- * 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());
- }
- boolean hasFilterEntries = (get("Filter") != null);
- if (hasFilterEntries) {
- this.filters.setDisableAllFilters(true);
- }
- }
- 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("\nstream\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("\nstream\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(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
- * {@inheritDoc}
- */
- @Override
- public int output(OutputStream stream) throws IOException {
- setupFilterList();
-
- CountingOutputStream cout = new CountingOutputStream(stream);
- StringBuilder textBuffer = new StringBuilder(64);
-
- StreamCache encodedStream = null;
- final Object lengthEntry;
- if (encodeOnTheFly) {
- if (!refLength.hasObjectNumber()) {
- registerChildren();
- }
- lengthEntry = refLength;
- } else {
- encodedStream = encodeStream();
- lengthEntry = encodedStream.getSize();
- }
-
- populateStreamDict(lengthEntry);
- dictionary.writeDictionary(cout, textBuffer);
-
- //Send encoded stream to target OutputStream
- PDFDocument.flushTextBuffer(textBuffer, cout);
- if (encodedStream == null) {
- encodeAndWriteStream(cout, refLength);
- } else {
- outputStreamData(encodedStream, cout);
- encodedStream.clear(); //Encoded stream can now be discarded
- }
-
- PDFDocument.flushTextBuffer(textBuffer, cout);
- return cout.getCount();
- }
-
- @Override
- public void setDocument(PDFDocument doc) {
- dictionary.setDocument(doc);
- super.setDocument(doc);
- }
-
- /**
- * Populates the dictionary with all necessary entries for the stream.
- * Override this method if you need additional entries.
- * @param lengthEntry value for the /Length entry
- */
- protected void populateStreamDict(Object lengthEntry) {
- put("Length", lengthEntry);
- if (!getFilterList().isDisableAllFilters()) {
- getFilterList().putFilterDictEntries(dictionary);
- }
- }
-
- /**
- * 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
- }
-
- /**
- * Whether multiple filters can be applied.
- * @return true if multiple filters allowed
- */
- protected boolean multipleFiltersAllowed() {
- return true;
- }
-
- @Override
- public void getChildren(Set<PDFObject> children) {
- dictionary.getChildren(children);
- if (encodeOnTheFly) {
- children.add(refLength);
- }
- }
-
- public void registerChildren() {
- if (encodeOnTheFly) {
- getDocument().registerObject(refLength);
- }
- }
- }
|