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/fonts/otf/GlyphSubstitutionTableReader.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.fonts.otf;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import com.itextpdf.text.pdf.Glyph;
import com.itextpdf.text.pdf.RandomAccessFileOrArray;

/**
 * <p>
 * Parses an OpenTypeFont file and reads the Glyph Substitution Table. This table governs how two or more Glyphs should be merged
 * to a single Glyph. This is especially useful for Asian languages like Bangla, Hindi, etc.
 * </p>
 * <p>
 * This has been written according to the OPenTypeFont specifications. This may be found <a href="http://www.microsoft.com/typography/otspec/gsub.htm">here</a>.
 * </p>
 * 
 * @author <a href="mailto:paawak@gmail.com">Palash Ray</a>
 */
public class GlyphSubstitutionTableReader extends OpenTypeFontTableReader {

    private final int[] glyphWidthsByIndex;
    private final Map<Integer, Character> glyphToCharacterMap;
    private Map<Integer, List<Integer>> rawLigatureSubstitutionMap;

    public GlyphSubstitutionTableReader(RandomAccessFileOrArray rf, int gsubTableLocation, 
    		Map<Integer, Character> glyphToCharacterMap, int[] glyphWidthsByIndex) throws IOException {
        super(rf, gsubTableLocation);
        this.glyphWidthsByIndex = glyphWidthsByIndex;
        this.glyphToCharacterMap = glyphToCharacterMap;
    }
    
    public void read() throws FontReadingException { 
        rawLigatureSubstitutionMap = new LinkedHashMap<Integer, List<Integer>>();
        startReadingTable();
    }
    
    public Map<String, Glyph> getGlyphSubstitutionMap() throws FontReadingException {
        Map<String, Glyph> glyphSubstitutionMap = new LinkedHashMap<String, Glyph>();
        
        for (Integer glyphIdToReplace : rawLigatureSubstitutionMap.keySet()) {
            List<Integer> constituentGlyphs = rawLigatureSubstitutionMap.get(glyphIdToReplace);
            StringBuilder chars = new StringBuilder(constituentGlyphs.size());
            
            for (Integer constituentGlyphId : constituentGlyphs) {
                chars.append(getTextFromGlyph(constituentGlyphId, glyphToCharacterMap));
            }
            
            Glyph glyph = new Glyph(glyphIdToReplace, glyphWidthsByIndex[glyphIdToReplace], chars.toString());
            
            glyphSubstitutionMap.put(glyph.chars, glyph);
        }
        
        return Collections.unmodifiableMap(glyphSubstitutionMap);
    }
    
    private String getTextFromGlyph(int glyphId, Map<Integer, Character> glyphToCharacterMap) throws FontReadingException {
        
        StringBuilder chars = new StringBuilder(1);
        
        Character c = glyphToCharacterMap.get(glyphId);
        
        if (c == null) {
            // it means this represents a compound glyph
            List<Integer> constituentGlyphs = rawLigatureSubstitutionMap.get(glyphId);
            
            if (constituentGlyphs == null || constituentGlyphs.isEmpty()) {
                throw new FontReadingException("No corresponding character or simple glyphs found for GlyphID=" + glyphId);
            }
            
            for (int constituentGlyphId : constituentGlyphs) {
                chars.append(getTextFromGlyph(constituentGlyphId, glyphToCharacterMap));
            }
            
        } else {
            chars.append(c.charValue());
        }
        
        return chars.toString();
    }
    
    @Override
    protected void readSubTable(int lookupType, int subTableLocation) throws IOException {
        
        if (lookupType == 1) {
            readSingleSubstitutionSubtable(subTableLocation);
        } else if (lookupType == 4) {
            readLigatureSubstitutionSubtable(subTableLocation);
        } else {
            System.err.println("LookupType " + lookupType + " is not yet handled for " + GlyphSubstitutionTableReader.class.getSimpleName());
        }
        
    }

    /**
     * LookupType 1: Single Substitution Subtable
     */
    private void readSingleSubstitutionSubtable(int subTableLocation) throws IOException { 
        rf.seek(subTableLocation);
        
        int substFormat = rf.readShort();
        LOG.debug("substFormat=" + substFormat);
        
        if (substFormat == 1) {
            int coverage = rf.readShort();
            LOG.debug("coverage=" + coverage);
            
            int deltaGlyphID = rf.readShort();
            LOG.debug("deltaGlyphID=" + deltaGlyphID);
            
            List<Integer> coverageGlyphIds = readCoverageFormat(subTableLocation + coverage);
            
            for (int coverageGlyphId : coverageGlyphIds) {
                int substituteGlyphId = coverageGlyphId + deltaGlyphID;
                rawLigatureSubstitutionMap.put(substituteGlyphId, Arrays.asList(coverageGlyphId)); 
            }
        } else if (substFormat == 2) {
            int coverage = rf.readShort();
            LOG.debug("coverage=" + coverage);
            int glyphCount = rf.readUnsignedShort();
            int[] substitute = new int[glyphCount];
            for (int k = 0; k < glyphCount; ++k) {
                substitute[k] = rf.readUnsignedShort();
            }
            List<Integer> coverageGlyphIds = readCoverageFormat(subTableLocation + coverage);
            for (int k = 0; k < glyphCount; ++k) {
                rawLigatureSubstitutionMap.put(substitute[k], Arrays.asList(coverageGlyphIds.get(k))); 
            }
            
        } else {
            throw new IllegalArgumentException("Bad substFormat: " + substFormat);
        }
    }

    /**
     * LookupType 4: Ligature Substitution Subtable
     */
    private void readLigatureSubstitutionSubtable(int ligatureSubstitutionSubtableLocation) throws IOException {
        rf.seek(ligatureSubstitutionSubtableLocation);
        int substFormat = rf.readShort();
        LOG.debug("substFormat=" + substFormat);

        if (substFormat != 1) {
            throw new IllegalArgumentException("The expected SubstFormat is 1");
        }

        int coverage = rf.readShort();
        LOG.debug("coverage=" + coverage);

        int ligSetCount = rf.readShort();

        List<Integer> ligatureOffsets = new ArrayList<Integer>(ligSetCount);

        for (int i = 0; i < ligSetCount; i++) {
            int ligatureOffset = rf.readShort();
            ligatureOffsets.add(ligatureOffset);
        }

        List<Integer> coverageGlyphIds = readCoverageFormat(ligatureSubstitutionSubtableLocation + coverage);

        if (ligSetCount != coverageGlyphIds.size()) {
            throw new IllegalArgumentException("According to the OpenTypeFont specifications, the coverage count should be equal to the no. of LigatureSetTables");
        }

        for (int i = 0; i < ligSetCount; i++) {

            int coverageGlyphId = coverageGlyphIds.get(i);
            int ligatureOffset = ligatureOffsets.get(i);
            LOG.debug("ligatureOffset=" + ligatureOffset);
            readLigatureSetTable(ligatureSubstitutionSubtableLocation + ligatureOffset, coverageGlyphId);
        }

    }

    private void readLigatureSetTable(int ligatureSetTableLocation, int coverageGlyphId) throws IOException {
        rf.seek(ligatureSetTableLocation);
        int ligatureCount = rf.readShort();
        LOG.debug("ligatureCount=" + ligatureCount);

        List<Integer> ligatureOffsets = new ArrayList<Integer>(ligatureCount);

        for (int i = 0; i < ligatureCount; i++) {
            int ligatureOffset = rf.readShort();
            ligatureOffsets.add(ligatureOffset);
        }

        for (int ligatureOffset : ligatureOffsets) {
            readLigatureTable(ligatureSetTableLocation + ligatureOffset, coverageGlyphId);
        }
    }

    private void readLigatureTable(int ligatureTableLocation, int coverageGlyphId) throws IOException {
        rf.seek(ligatureTableLocation);
        int ligGlyph = rf.readShort();
        LOG.debug("ligGlyph=" + ligGlyph);
        
        int compCount = rf.readShort();

        List<Integer> glyphIdList = new ArrayList<Integer>();

        glyphIdList.add(coverageGlyphId);

        for (int i = 0; i < compCount - 1; i++) {
            int glyphId = rf.readShort();
            glyphIdList.add(glyphId);
        }
        
        LOG.debug("glyphIdList=" + glyphIdList);

        List<Integer> previousValue = rawLigatureSubstitutionMap.put(ligGlyph, glyphIdList);
        
        if (previousValue != null) {
        	LOG.warn("!!!!!!!!!!glyphId=" + ligGlyph 
        			+ ",\npreviousValue=" + previousValue
        			+ ",\ncurrentVal=" + glyphIdList);
        }
    }

}

⏎ com/itextpdf/text/pdf/fonts/otf/GlyphSubstitutionTableReader.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
Download 

⇒ iText-2.1.6.jar - iText, a JAVA-PDF library

⇐ iText layout.jar Source Code

⇑ Download and Install iText Java Library

⇑⇑ iText for PDF Generation