Check for index out of range in GlyphDataTable.ReadFlags() and fix #1199

src/UglyToad.PdfPig.Fonts/TrueType/Tables/GlyphDataTable.cs

@@ -338,7 +338,15 @@ private static SimpleGlyphFlags[] ReadFlags(TrueTypeDataBytes data, int pointCou
 
                     for (int j = 0; j < numberOfRepeats; j++)
                     {
-                        result[i + j + 1] = result[i];
+                        int p = i + j + 1;
+                        if (p >= result.Length)
+                        {
+                            // Unsure why this happens but fixes #1199
+                            // TODO - Is there a better fix?
+                            break;
+                        }
+
+                        result[p] = result[i];
                     }
 
                     i += numberOfRepeats;

src/UglyToad.PdfPig.Tests/Integration/GithubIssuesTests.cs

@@ -8,6 +8,21 @@
 
     public class GithubIssuesTests
     {
+        [Fact]
+        public void Issue1199()
+        {
+            var path = IntegrationHelpers.GetDocumentPath("TrueTypeTablesGlyphDataTableReadGlyphsError.pdf");
+
+            using (var document = PdfDocument.Open(path, new ParsingOptions() { UseLenientParsing = true }))
+            {
+                for (int p = 1; p <= document.NumberOfPages; p++)
+                {
+                    var page = document.GetPage(p);
+                    Assert.NotNull(page);
+                }
+            }
+        }
+
         [Fact]
         public void Issue1183()
         {