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 1.7' section 3.2.7 (page 60-63).
*
* @see PdfObject
* @see PdfDictionary
*/
public class PdfStream extends PdfDictionary {
// membervariables
/**
* A possible compression level.
*
* @since 2.1.3
*/
public static final int DEFAULT_COMPRESSION = -1;
/**
* A possible compression level.
*
* @since 2.1.3
*/
public static final int NO_COMPRESSION = 0;
/**
* A possible compression level.
*
* @since 2.1.3
*/
public static final int BEST_SPEED = 1;
/**
* A possible compression level.
*
* @since 2.1.3
*/
public static final int BEST_COMPRESSION = 9;
/** is the stream compressed? */
protected boolean compressed = false;
/**
* The level of compression.
*
* @since 2.1.3
*/
protected int compressionLevel = NO_COMPRESSION;
protected ByteArrayOutputStream streamBytes = null;
protected InputStream inputStream;
protected PdfIndirectReference ref;
protected int inputStreamLength = -1;
protected PdfWriter writer;
protected int rawLength;
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;
rawLength = bytes.length;
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 constructor
* {@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);
}
/**
* Gets the raw length of the stream.
*
* @return the raw length of the stream
*/
public int getRawLength() {
return rawLength;
}
/**
* Compresses the stream.
*/
public void flateCompress() {
flateCompress(DEFAULT_COMPRESSION);
}
/**
* Compresses the stream.
*
* @param compressionLevel
* the compression level (0 = best speed, 9 = best compression,
* -1 is default)
* @since 2.1.3
*/
public void flateCompress(int compressionLevel) {
if (!Document.compress)
return;
// check if the flateCompress-method has already been
if (compressed) {
return;
}
this.compressionLevel = compressionLevel;
if (inputStream != null) {
compressed = true;
return;
}
// check if a filter already exists
PdfObject filter = PdfReader.getPdfObject(get(PdfName.FILTER));
if (filter != null) {
if (filter.isName()) {
if (PdfName.FLATEDECODE.equals(filter))
return;
} else if (filter.isArray()) {
if (((PdfArray) filter).contains(PdfName.FLATEDECODE))
return;
} else {
throw new RuntimeException(
"Stream could not be compressed: filter is not a name or array.");
}
}
Deflater deflater = new Deflater(compressionLevel);
try {
// compress
ByteArrayOutputStream stream = new ByteArrayOutputStream();
DeflaterOutputStream zip = new DeflaterOutputStream(stream,
deflater);
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);
} finally {
try {
// Closes the compressor and discards any unprocessed input.
// This is never called as the DeflaterOutputStream does not
// use the default Deflater.
deflater.end();
} catch (Throwable t) {
// Catch any object thrown by the df.end() call, e.g.
// NullPointerException for example.
}
}
}
// 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);
}
/**
* @see com.lowagie.text.pdf.PdfDictionary#toPdf(com.lowagie.text.pdf.PdfWriter,
* java.io.OutputStream)
*/
public void toPdf(PdfWriter writer, OutputStream os) throws IOException {
if (inputStream != null && compressed)
put(PdfName.FILTER, PdfName.FLATEDECODE);
PdfEncryption crypto = null;
if (writer != null)
crypto = writer.getEncryption();
if (crypto != null) {
PdfObject filter = get(PdfName.FILTER);
if (filter != null) {
if (PdfName.CRYPT.equals(filter))
crypto = null;
else if (filter.isArray()) {
ArrayList af = ((PdfArray) filter).getArrayList();
if (!af.isEmpty() && PdfName.CRYPT.equals(af.get(0)))
crypto = null;
}
}
}
PdfObject nn = get(PdfName.LENGTH);
if (crypto != null && nn != null && nn.isNumber()) {
int sz = ((PdfNumber) nn).intValue();
put(PdfName.LENGTH, new PdfNumber(crypto.calculateStreamSize(sz)));
superToPdf(writer, os);
put(PdfName.LENGTH, nn);
} else
superToPdf(writer, os);
os.write(STARTSTREAM);
if (inputStream != null) {
Deflater deflater = null;
try {
rawLength = 0;
DeflaterOutputStream def = null;
OutputStreamCounter osc = new OutputStreamCounter(os);
OutputStreamEncryption ose = null;
OutputStream fout = osc;
if (crypto != null && !crypto.isEmbeddedFilesOnly())
fout = ose = crypto.getEncryptionStream(fout);
if (compressed) {
deflater = new Deflater(compressionLevel);
fout = def = new DeflaterOutputStream(fout, deflater,
0x8000);
}
byte buf[] = new byte[4192];
while (true) {
int n = inputStream.read(buf);
if (n <= 0)
break;
fout.write(buf, 0, n);
rawLength += n;
}
if (def != null)
def.finish();
if (ose != null)
ose.finish();
inputStreamLength = osc.getCounter();
} finally {
try {
// Closes the compressor and discards any unprocessed input.
// This is never called as the DeflaterOutputStream does not
// use the default Deflater.
deflater.end();
} catch (Throwable t) {
// Catch any object thrown by the df.end() call, e.g.
// NullPointerException for example.
}
}
} else {
if (crypto != null && !crypto.isEmbeddedFilesOnly()) {
byte b[];
if (streamBytes != null) {
b = crypto.encryptByteArray(streamBytes.toByteArray());
} else {
b = crypto.encryptByteArray(bytes);
}
os.write(b);
} else {
if (streamBytes != null)
streamBytes.writeTo(os);
else
os.write(bytes);
}
}
os.write(ENDSTREAM);
}
/**
* Writes the data content to an OutputStream.
*
* @param os
* the destination to write to
* @throws IOException
* on error
*/
public void writeContent(OutputStream os) throws IOException {
if (streamBytes != null)
streamBytes.writeTo(os);
else if (bytes != null)
os.write(bytes);
}
/**
* @see com.lowagie.text.pdf.PdfObject#toString()
*/
public String toString() {
if (get(PdfName.TYPE) == null)
return "Stream";
return "Stream of type: " + get(PdfName.TYPE);
}
}