Improve metadata parsing for pdf/a documents

DEVSIX-9088

Autoported commit.
Original commit hash: [3b5d4bd4d]
Manual files:
kernel/src/main/java/com/itextpdf/kernel/xmp/impl/XMPUtilsImpl.java

Author: Dmitry Radchuk

itext.tests/itext.pdfa.tests/itext/pdfa/PdfAXmpTest.cs

@@ -29,6 +29,7 @@ You should have received a copy of the GNU Affero General Public License
 using iText.Kernel.XMP;
 using iText.Kernel.XMP.Options;
 using iText.Test;
+using iText.Test.Attributes;
 
 namespace iText.Pdfa {
     [NUnit.Framework.Category("IntegrationTest")]
@@ -112,6 +113,34 @@ public virtual void SaveAndReadDocumentWithCanonicalXmpMetadata() {
             }
         }
 
+        [NUnit.Framework.Test]
+        public virtual void ReadDocumentWithControlCharactersInXMPMetadata() {
+            String src = sourceFolder + "pdfs/docWithControlCharactersInXmp.pdf";
+            using (PdfADocument document = new PdfADocument(new PdfReader(src), new PdfWriter(new MemoryStream()), new 
+                StampingProperties())) {
+                NUnit.Framework.Assert.AreEqual(PdfConformance.PDF_A_3A, document.GetConformance());
+            }
+        }
+
+        [NUnit.Framework.Test]
+        public virtual void ReadDocumentWithInvalidConformance() {
+            String src = sourceFolder + "pdfs/docWithInvalidConformance.pdf";
+            using (PdfDocument document = new PdfDocument(new PdfReader(src), new PdfWriter(new MemoryStream()), new StampingProperties
+                ())) {
+                NUnit.Framework.Assert.AreEqual(PdfConformance.PDF_NONE_CONFORMANCE, document.GetConformance());
+            }
+        }
+
+        [LogMessage(iText.IO.Logs.IoLogMessageConstant.EXCEPTION_WHILE_UPDATING_XMPMETADATA)]
+        [NUnit.Framework.Test]
+        public virtual void ReadDocumentWithInvalidXMPMetadata() {
+            String src = sourceFolder + "pdfs/docWithInvalidMetadata.pdf";
+            using (PdfDocument document = new PdfDocument(new PdfReader(src), new PdfWriter(new MemoryStream()), new StampingProperties
+                ())) {
+                NUnit.Framework.Assert.AreEqual(PdfConformance.PDF_NONE_CONFORMANCE, document.GetConformance());
+            }
+        }
+
         [NUnit.Framework.Test]
         public virtual void TestPdfUAExtensionMetadata() {
             String outFile = destinationFolder + "testPdfUAExtensionMetadata.pdf";

itext.tests/itext.pdfa.tests/resources/itext/pdfa/pdfs/docWithControlCharactersInXmp.pdf

@@ -75,7 +75,7 @@ public override int Read() {
 		/// <param name="off">   Offset at which to start writing characters </param>
 		/// <param name="len">   Maximum number of characters to read
 		/// </param>
-		/// <returns>     The number of characters read, or -1 if the end of the
+		/// <returns>     The number of characters read, or 0 if the end of the
 		///             stream has been reached
 		/// </returns>
 		public override int Read(char[] cbuf, int off, int len) {

itext.tests/itext.pdfa.tests/resources/itext/pdfa/pdfs/docWithInvalidConformance.pdf

@@ -674,6 +674,7 @@ public virtual PdfConformance GetPdfConformance() {
                     pdfConformance = PdfConformance.GetConformance(xmpMeta);
                 }
                 catch (XMPException) {
+                    pdfConformance = PdfConformance.PDF_NONE_CONFORMANCE;
                 }
             }
             return pdfConformance;

itext.tests/itext.pdfa.tests/resources/itext/pdfa/pdfs/docWithInvalidMetadata.pdf

@@ -103,7 +103,7 @@ public override int Read(char[] cbuf, int off, int len) {
                     }
                 }
             }
-            return read > 0 || available ? read : -1;
+            return read > 0 || available ? read : XMPUtilsImpl.EofReadBytesValue();
         }
 
         /// <summary>Processes numeric escaped chars to find out if they are a control character.</summary>

itext/itext.commons/itext/commons/utils/PushbackReader.cs

@@ -57,6 +57,17 @@ private XMPUtilsImpl()
 		{
 		}
 
+		/// <summary>
+		/// Return value when eof encountered of <seealso cref="System.IO.TextReader.Read(char[], int, int)"/>.
+		/// </summary>
+		/// <returns>
+		/// platform dependent eof read value (0 for C#)
+		/// </returns>
+		public static int EofReadBytesValue()
+		{
+			return 0;
+		}
+
 		// EMPTY
 		/// <seealso cref="iText.Kernel.XMP.XMPUtils.CatenateArrayItems(iText.Kernel.XMP.XMPMeta, System.String, System.String, System.String, System.String, bool)
 		/// 	"/>

itext/itext.kernel/itext/kernel/pdf/PdfReader.cs

@@ -1 +1 @@
-6691f70abaf4119ab2e862f6b708e46bb3e76666
+3ccc99bd8391813f729cf2b6c656252687f17629