Handle unrepresentable datetimes

MatFileHandler.Tests/MatFileReaderTests.cs

@@ -449,6 +449,19 @@ namespace MatFileHandler.Tests
             Assert.That(duration[2], Is.EqualTo(new TimeSpan(1, 3, 5)));
         }
 
+        /// <summary>
+        /// Test unrepresentable datetime.
+        /// </summary>
+        [Test]
+        public void TestDatetime_Unrepresentable()
+        {
+            var matFile = GetTests("good")["datetime-unrepresentable"];
+            var obj = matFile["d"].Value as IMatObject;
+            var datetime = new DatetimeAdapter(obj);
+            var d0 = datetime[0];
+            Assert.That(d0, Is.Null);
+        }
+
         private static AbstractTestDataFactory<IMatFile> GetTests(string factoryName) =>
             new MatTestDataFactory(Path.Combine(TestDirectory, factoryName));
 

MatFileHandler/DatetimeAdapter.cs

@@ -57,6 +57,17 @@ namespace MatFileHandler
         /// </summary>
         /// <param name="list">Indices.</param>
         /// <returns>Value converted to  <see cref="DateTimeOffset"/>.</returns>
-        public DateTimeOffset this[params int[] list] => epoch.AddMilliseconds(data[Dimensions.DimFlatten(list)]);
+        public DateTimeOffset? this[params int[] list]
+        {
+            get
+            {
+                var milliseconds = data[Dimensions.DimFlatten(list)];
+                if (milliseconds < -62_135_596_800_000.0 || milliseconds > 253_402_300_799_999.0)
+                {
+                    return null;
+                }
+                return epoch.AddMilliseconds(milliseconds);
+            }
+        }
     }
 }