Resolve several TODOs in font processing logic

DEVSIX-6849

Author: dmitry.radchuk

io/src/main/java/com/itextpdf/io/font/otf/GsubLookupType4.java

@@ -67,7 +67,6 @@ public GsubLookupType4(OpenTypeFontTableReader openReader, int lookupFlag, int[]
 
     @Override
     public boolean transformOne(GlyphLine line) {
-        //TODO >
         if (line.idx >= line.end)
             return false;
         boolean changed = false;

io/src/main/java/com/itextpdf/io/font/otf/OpenTypeFontTableReader.java

@@ -149,7 +149,6 @@ public List<OpenTableLookup> getLookups(FeatureRecord[] features) {
     }
 
     public List<OpenTableLookup> getLookups(FeatureRecord feature) {
-        //TODO see getLookups(FeatureRecord[]) method. Is it realy make sense to order features?
         List<OpenTableLookup> ret = new ArrayList<>(feature.lookups.length);
         for (int idx : feature.lookups) {
             ret.add(lookupList.get(idx));

io/src/test/java/com/itextpdf/io/font/otf/GsubLookupType4Test.java

@@ -0,0 +1,40 @@
+package com.itextpdf.io.font.otf;
+
+import com.itextpdf.io.font.FontProgramFactory;
+import com.itextpdf.io.font.TrueTypeFont;
+import com.itextpdf.test.ExtendedITextTest;
+import com.itextpdf.test.annotations.type.IntegrationTest;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+@Category(IntegrationTest.class)
+public class GsubLookupType4Test extends ExtendedITextTest {
+
+    private static final String RESOURCE_FOLDER = "./src/test/resources/com/itextpdf/io/font/otf/GsubLookupType4Test/";
+
+    @Test
+    public void testNoIndexOutOfBound() throws IOException {
+        TrueTypeFont fontProgram = (TrueTypeFont) FontProgramFactory.createFont(RESOURCE_FOLDER + "DejaVuSansMono.ttf");
+        GlyphSubstitutionTableReader gsubTableReader = fontProgram.getGsubTable();
+
+        List<Glyph> glyphs = Arrays.asList(new Glyph(1, 1, 1),
+                                           new Glyph(1, 1, 1),
+                                           new Glyph(1, 1, 1),
+                                           new Glyph(1, 1, 1),
+                                           new Glyph(1, 1, 1),
+                                           new Glyph(1, 1, 1));
+
+        GlyphLine gl = new GlyphLine(glyphs);
+        gl.idx = gl.end;
+
+        GsubLookupType4 lookup = (GsubLookupType4) gsubTableReader.getLookupTable(6);
+
+        //Assert that no exception is thrown if gl.idx = gl.end
+        Assert.assertFalse(lookup.transformOne(gl));
+    }
+}

io/src/test/java/com/itextpdf/io/font/otf/OpenTypeFontTableReaderTest.java

@@ -26,6 +26,8 @@ This file is part of the iText (R) project.
 import com.itextpdf.io.font.TrueTypeFont;
 import com.itextpdf.test.ExtendedITextTest;
 import com.itextpdf.test.annotations.type.UnitTest;
+
+import java.util.List;
 import org.junit.Assert;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
@@ -54,4 +56,26 @@ public void testFetchLangSysByTag() throws IOException {
         Assert.assertNull(gsub.getLanguageRecord("mym3"));
         Assert.assertNull(gsub.getLanguageRecord("mym3", LanguageTags.SGAW_KAREN));
     }
+
+
+    @Test
+    public void testGetLookupsArray() throws IOException {
+        TrueTypeFont fontProgram = (TrueTypeFont) FontProgramFactory.createFont(RESOURCE_FOLDER + "NotoSansMyanmar-Regular.ttf");
+        GlyphSubstitutionTableReader gsub = fontProgram.getGsubTable();
+        FeatureRecord firstRecord = new FeatureRecord();
+        firstRecord.lookups = new int[]{5, 2};
+        firstRecord.tag = "1";
+        FeatureRecord secondRecord = new FeatureRecord();
+        secondRecord.lookups = new int[]{4, 10};
+        secondRecord.tag = "2";
+        FeatureRecord[] records = new FeatureRecord[]{firstRecord, secondRecord};
+
+        int[] lookupsLocations = gsub.getLookups(firstRecord).stream().mapToInt(record -> record.subTableLocations[0]).toArray();
+        int[] expected = new int[]{142610, 142436};
+        Assert.assertArrayEquals(expected, lookupsLocations);
+
+        lookupsLocations = gsub.getLookups(records).stream().mapToInt(record -> record.subTableLocations[0]).toArray();
+        expected = new int[]{142436, 142538, 142610, 143908};
+        Assert.assertArrayEquals(expected, lookupsLocations);
+    }
 }