itextpdf.jar is a component in iText 5 Java library to provide core functionalities. iText Java library allows you to generate and manage PDF documents.

The Source Code files are provided at iText GitHub site.

You can compile it to generate your JAR file, using pom.xml as the build configuration file.

The source code of itextpdf-5.5.14.jar is provided below:

⏎ com/itextpdf/text/pdf/PdfStream.java

/*
 *
 * This file is part of the iText (R) project.
    Copyright (c) 1998-2020 iText Group NV
 * Authors: Bruno Lowagie, Paulo Soares, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
 * ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
 * OF THIRD PARTY RIGHTS
 *
 * This program 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 Affero General Public License for more details.
 * You should have received a copy of the GNU Affero General Public License
 * along with this program; if not, see http://www.gnu.org/licenses or write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA, 02110-1301 USA, or download the license from the following URL:
 * http://itextpdf.com/terms-of-use/
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License,
 * a covered work must retain the producer line in every PDF that is created
 * or manipulated using iText.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the iText software without
 * disclosing the source code of your own applications.
 * These activities include: offering paid services to customers as an ASP,
 * serving PDFs on the fly in a web application, shipping iText with a closed
 * source product.
 *
 * For more information, please contact iText Software Corp. at this
 * address: sales@itextpdf.com
 */
package com.itextpdf.text.pdf;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.zip.Deflater;
import java.util.zip.DeflaterOutputStream;
import com.itextpdf.text.error_messages.MessageLocalization;

import com.itextpdf.text.DocWriter;
import com.itextpdf.text.Document;
import com.itextpdf.text.ExceptionConverter;
import com.itextpdf.text.pdf.internal.PdfIsoKeys;

/**
 * <CODE>PdfStream</CODE> is the Pdf stream object.
 * <P>
 * 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.<BR>
 * A stream consists of a dictionary that describes a sequence of characters, followed by
 * the keyword <B>stream</B>, followed by zero or more lines of characters, followed by
 * the keyword <B>endstream</B>.<BR>
 * All streams must be <CODE>PdfIndirectObject</CODE>s. The stream dictionary must be a direct
 * object. The keyword <B>stream</B> that follows the stream dictionary should be followed by
 * a carriage return and linefeed or just a linefeed.<BR>
 * Remark: In this version only the FLATEDECODE-filter is supported.<BR>
 * This object is described in the 'Portable Document Format Reference Manual version 1.7'
 * section 3.2.7 (page 60-63).<BR>
 *
 * @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 <CODE>PdfStream</CODE>-object.
 *
 * @param		bytes			content of the new <CODE>PdfObject</CODE> as an array of <CODE>byte</CODE>.
 */
 
    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 <CODE>InputStream</CODE>
     * is totally consumed but is not closed. The general usage is:
     * <p>
     * <pre>
     * InputStream in = ...;
     * PdfStream stream = new PdfStream(in, writer);
     * stream.flateCompress();
     * writer.addToBody(stream);
     * stream.writeLength();
     * in.close();
     * </pre>
     * @param inputStream the data to write to this stream
     * @param writer the <CODE>PdfWriter</CODE> 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 <CODE>PdfStream</CODE>-object.
 */
    
    protected PdfStream() {
        super();
        type = STREAM;
    }
    
    /**
     * Writes the stream length to the <CODE>PdfWriter</CODE>.
     * <p>
     * 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(MessageLocalization.getComposedMessage("writelength.can.only.be.called.in.a.contructed.pdfstream.inputstream.pdfwriter"));
        if (inputStreamLength == -1)
            throw new IOException(MessageLocalization.getComposedMessage("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(MessageLocalization.getComposedMessage("stream.could.not.be.compressed.filter.is.not.a.name.or.array"));
            }
        }
        try {
            // compress
            ByteArrayOutputStream stream = new ByteArrayOutputStream();
            Deflater deflater = new Deflater(compressionLevel);
            DeflaterOutputStream zip = new DeflaterOutputStream(stream, deflater);
            if (streamBytes != null)
                streamBytes.writeTo(zip);
            else
                zip.write(bytes);
            zip.close();
            deflater.end();
            // 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(0, 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);
    }
    
    /**
     * @see com.itextpdf.text.pdf.PdfDictionary#toPdf(com.itextpdf.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()) {
                    PdfArray a = (PdfArray)filter;
                    if (!a.isEmpty() && PdfName.CRYPT.equals(a.getPdfObject(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);
        PdfWriter.checkPdfIsoConformance(writer, PdfIsoKeys.PDFISOKEY_STREAM, this);
        os.write(STARTSTREAM);
        if (inputStream != null) {
            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);
            Deflater deflater = null;
            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();
                deflater.end();
            }
            if (ose != null)
                ose.finish();
            inputStreamLength = (int)osc.getCounter();
        }
        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 <CODE>OutputStream</CODE>.
     * @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.itextpdf.text.pdf.PdfObject#toString()
     */
    public String toString() {
    	if (get(PdfName.TYPE) == null) return "Stream";
    	return "Stream of type: " + get(PdfName.TYPE);
    }
}

⏎ com/itextpdf/text/pdf/PdfStream.java

Or download all of them as a single archive file:

File name: itextpdf-5.5.14-fyi.zip
File size: 2163839 bytes
Release date: 2009-10-09
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⇒ iText-2.1.6.jar - iText, a JAVA-PDF library

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