Added a FieldCount property.

Benchmarks/Millistream.Streaming.Benchmarks/MessageBenchmarks.cs

@@ -463,6 +463,9 @@ public void AddListBytes()
         [Benchmark]
         public int GetActiveCount() => _message.ActiveCount;
 
+        [Benchmark]
+        public int GetFieldCount() => _message.FieldCount;
+
         [Benchmark]
         public void SetUtf8Validation() => _message.Utf8Validation = false;
 

Source/Millistream.Streaming/IMessage.cs

@@ -22,6 +22,11 @@ public interface IMessage
         /// </summary>
         int ActiveCount { get; }
 
+        /// <summary>
+        /// The number of added fields to the current message.
+        /// </summary>
+        int FieldCount { get; }
+
         /// <summary>
         /// Enables or disables the UTF-8 validation performed in <see cref="AddString(uint, string)"/> and <see cref="AddString(uint, string, int)"/>. It's enabled by default.
         /// </summary>

Source/Millistream.Streaming/Interop/NativeImplementation.cs

@@ -42,6 +42,7 @@ unsafe internal sealed class NativeImplementation
         internal readonly delegate* unmanaged[Cdecl]<IntPtr, ref IntPtr, int> mdf_message_serialize;
         internal readonly delegate* unmanaged[Cdecl]<IntPtr, IntPtr, int> mdf_message_deserialize;
         internal readonly delegate* unmanaged[Cdecl]<IntPtr, MDF_MSG_OPTION, int, int> mdf_message_set_property;
+        internal readonly delegate* unmanaged[Cdecl]<IntPtr, int> mdf_message_get_num_fields;
 
         internal NativeImplementation(string libraryPath)
         {
@@ -112,6 +113,8 @@ internal NativeImplementation(string libraryPath)
                 mdf_message_deserialize = (delegate* unmanaged[Cdecl]<IntPtr, IntPtr, int>)address;
             if (nativeLibrary.TryGetExport(lib, nameof(mdf_message_set_property), out address))
                 mdf_message_set_property = (delegate* unmanaged[Cdecl]<IntPtr, MDF_MSG_OPTION, int, int>)address;
+            if (nativeLibrary.TryGetExport(lib, nameof(mdf_message_get_num_fields), out address))
+                mdf_message_get_num_fields = (delegate* unmanaged[Cdecl]<IntPtr, int>)address;
         }
 
         internal static NativeImplementation Default => s_defaultImplementation ??= new(null);

Source/Millistream.Streaming/Message.cs

@@ -98,6 +98,21 @@ public int ActiveCount
             }
         }
 
+        /// <summary>
+        /// The number of added fields to the current message.
+        /// </summary>
+        /// <exception cref="InvalidOperationException">The installed version of the native library doesn't include the mdf_message_get_num_fields function.</exception>
+        /// <exception cref="ObjectDisposedException">The <see cref="Message"/> instance has been disposed.</exception>
+        public int FieldCount
+        {
+            get
+            {
+                ThrowIfDisposed();
+                ThrowIfNativeFunctionIsMissing(_nativeImplementation.mdf_message_get_num_fields, nameof(_nativeImplementation.mdf_message_get_num_fields));
+                return _nativeImplementation.mdf_message_get_num_fields(Handle);
+            }
+        }
+
         /// <summary>
         /// Enables or disables the UTF-8 validation performed in <see cref="AddString(uint, string)"/> and <see cref="AddString(uint, string, int)"/>. It's enabled by default.
         /// </summary>

Tests/Millistream.Streaming.IntegrationTests/MarketDataFeedTests.cs

@@ -256,20 +256,24 @@ public void SendMultipleMessagesTest()
             Assert.IsTrue(message.AddNumeric(Field.MDF_F_REQUESTTYPE, StringConstants.RequestTypes.MDF_RT_IMAGE));
             Assert.IsTrue(message.AddString(Field.MDF_F_INSREFLIST, "772"));
             Assert.IsTrue(message.AddString(Field.MDF_F_REQUESTID, requestIds[0]));
+            Assert.AreEqual(1, message.ActiveCount);
+            Assert.AreEqual(4, message.FieldCount);
 
             Assert.IsTrue(message.Add(0, MessageReference.MDF_M_REQUEST));
             Assert.IsTrue(message.AddNumeric(Field.MDF_F_REQUESTCLASS, StringConstants.RequestClasses.MDF_RC_QUOTE));
             Assert.IsTrue(message.AddNumeric(Field.MDF_F_REQUESTTYPE, StringConstants.RequestTypes.MDF_RT_IMAGE));
             Assert.IsTrue(message.AddString(Field.MDF_F_INSREFLIST, "1146"));
             Assert.IsTrue(message.AddString(Field.MDF_F_REQUESTID, requestIds[1]));
+            Assert.AreEqual(2, message.ActiveCount);
+            Assert.AreEqual(4, message.FieldCount);
 
             Assert.IsTrue(message.Add(0, MessageReference.MDF_M_REQUEST));
             Assert.IsTrue(message.AddNumeric(Field.MDF_F_REQUESTCLASS, StringConstants.RequestClasses.MDF_RC_TRADE));
             Assert.IsTrue(message.AddNumeric(Field.MDF_F_REQUESTTYPE, StringConstants.RequestTypes.MDF_RT_IMAGE));
             Assert.IsTrue(message.AddString(Field.MDF_F_INSREFLIST, "105"));
             Assert.IsTrue(message.AddString(Field.MDF_F_REQUESTID, requestIds[2]));
-
             Assert.AreEqual(3, message.ActiveCount);
+            Assert.AreEqual(4, message.FieldCount);
 
             //send a request with 3 messages
             Assert.IsTrue(mdf.Send(message));
@@ -278,6 +282,7 @@ public void SendMultipleMessagesTest()
 
             message.Reset();
             Assert.AreEqual(0, message.ActiveCount);
+            Assert.AreEqual(0, message.FieldCount);
 
             Assert.IsTrue(message.Add(0, MessageReference.MDF_M_REQUEST));
             Assert.IsTrue(message.AddNumeric(Field.MDF_F_REQUESTCLASS, StringConstants.RequestClasses.MDF_RC_ORDER));
@@ -286,6 +291,7 @@ public void SendMultipleMessagesTest()
             string requestId = Guid.NewGuid().ToString();
             Assert.IsTrue(message.AddString(Field.MDF_F_REQUESTID, requestId));
             Assert.AreEqual(1, message.ActiveCount);
+            Assert.AreEqual(4, message.FieldCount);
 
             //send another request with a single message
             Assert.IsTrue(mdf.Send(message));

Tests/Millistream.Streaming.IntegrationTests/MessageTests.cs

@@ -305,8 +305,10 @@ public void ResetTest()
             using Message message = new Message();
             Assert.IsTrue(message.Add(0, MessageReference.MDF_M_QUOTE));
             Assert.AreEqual(1, message.ActiveCount);
+            Assert.AreEqual(0, message.FieldCount);
             message.Reset();
             Assert.AreEqual(0, message.ActiveCount);
+            Assert.AreEqual(0, message.FieldCount);
         }
 
         [TestMethod]
@@ -316,12 +318,16 @@ public void DeleteTest()
             Assert.IsTrue(message.Add(0, MessageReference.MDF_M_QUOTE));
             Assert.IsTrue(message.AddNumeric(Field.MDF_F_REQUESTCLASS, StringConstants.RequestClasses.MDF_RC_BASICDATA));
             Assert.AreEqual(1, message.ActiveCount);
+            Assert.AreEqual(1, message.FieldCount);
             Assert.IsTrue(message.Add(0, MessageReference.MDF_M_QUOTE));
             Assert.AreEqual(2, message.ActiveCount);
+            Assert.AreEqual(0, message.FieldCount);
             message.Delete();
             Assert.AreEqual(1, message.ActiveCount);
+            Assert.AreEqual(1, message.FieldCount);
             message.Delete();
             Assert.AreEqual(0, message.ActiveCount);
+            Assert.AreEqual(0, message.FieldCount);
         }
 
         [TestMethod]
@@ -381,18 +387,26 @@ public void MoveTest()
             const ulong SourceInsRef = 1;
             Assert.IsTrue(source.Add(SourceInsRef, MessageReference.MDF_M_REQUEST));
             Assert.IsTrue(source.AddNumeric(Field.MDF_F_REQUESTTYPE, StringConstants.RequestTypes.MDF_RT_IMAGE));
+            Assert.AreEqual(1, source.ActiveCount);
+            Assert.AreEqual(1, source.FieldCount);
             Assert.IsTrue(source.Add(SourceInsRef, MessageReference.MDF_M_BASICDATA));
             Assert.IsTrue(source.AddNumeric(Field.MDF_F_REQUESTTYPE, StringConstants.RequestTypes.MDF_RT_IMAGE));
+            Assert.AreEqual(2, source.ActiveCount);
+            Assert.AreEqual(1, source.FieldCount);
             Assert.IsTrue(source.Add(SourceInsRef, MessageReference.MDF_M_QUOTE));
             Assert.IsTrue(source.AddNumeric(Field.MDF_F_REQUESTTYPE, StringConstants.RequestTypes.MDF_RT_IMAGE));
             Assert.AreEqual(3, source.ActiveCount);
+            Assert.AreEqual(1, source.FieldCount);
 
             using Message destination = new Message();
             Assert.AreEqual(0, destination.ActiveCount);
+            Assert.AreEqual(0, destination.FieldCount);
 
             Assert.IsTrue(Message.Move(source, destination, 1, 10));
             Assert.AreEqual(0, source.ActiveCount);
+            Assert.AreEqual(0, source.FieldCount);
             Assert.AreEqual(3, destination.ActiveCount);
+            Assert.AreEqual(1, destination.FieldCount);
 
             Assert.IsFalse(Message.Move(source, null, 1, 10));
             Assert.IsTrue(Message.Move(destination, null, 10, 11));
@@ -419,16 +433,21 @@ public void SerializeAndDeserializeTest()
             using Message message2 = new Message();
             Assert.IsTrue(message2.Deserialize(s));
             Assert.AreEqual(2, message2.ActiveCount);
+            Assert.AreEqual(1, message2.FieldCount);
             Assert.IsTrue(message.Deserialize(s));
             message2.Reset();
             Assert.AreEqual(0, message2.ActiveCount);
+            Assert.AreEqual(0, message2.FieldCount);
             Assert.IsTrue(message2.Deserialize(result));
             Assert.AreEqual(2, message2.ActiveCount);
+            Assert.AreEqual(1, message2.FieldCount);
             message2.Reset();
             Assert.AreEqual(0, message2.ActiveCount);
+            Assert.AreEqual(0, message2.FieldCount);
             byte[] bytes = Encoding.ASCII.GetBytes(s);
             Assert.IsTrue(message2.Deserialize(bytes));
             Assert.AreEqual(2, message2.ActiveCount);
+            Assert.AreEqual(1, message2.FieldCount);
         }
     }
 }

Tests/Millistream.Streaming.UnitTests/MessageTests.cs

@@ -55,19 +55,28 @@ public void GetAndSetCompressionLevelTest()
         [TestMethod]
         public void GetCountTest()
         {
-            const int Num = 11;
-            _nativeImplementation.Setup(x => x.mdf_message_get_num(It.IsAny<IntPtr>())).Returns(Num);
+            const int Count = 11;
+            _nativeImplementation.Setup(x => x.mdf_message_get_num(It.IsAny<IntPtr>())).Returns(Count);
             using Message message = new();
-            Assert.AreEqual(Num, message.Count);
+            Assert.AreEqual(Count, message.Count);
         }
 
         [TestMethod]
-        public void GetCountActiveTest()
+        public void GetActiveCountTest()
         {
-            const int NumActive = 5;
-            _nativeImplementation.Setup(x => x.mdf_message_get_num_active(It.IsAny<IntPtr>())).Returns(NumActive);
+            const int Count = 5;
+            _nativeImplementation.Setup(x => x.mdf_message_get_num_active(It.IsAny<IntPtr>())).Returns(Count);
             using Message message = new();
-            Assert.AreEqual(NumActive, message.ActiveCount);
+            Assert.AreEqual(Count, message.ActiveCount);
+        }
+
+        [TestMethod]
+        public void GetFieldCountTest()
+        {
+            const int Count = 6;
+            _nativeImplementation.Setup(x => x.mdf_message_get_num_fields(It.IsAny<IntPtr>())).Returns(Count);
+            using Message message = new();
+            Assert.AreEqual(Count, message.FieldCount);
         }
 
         [TestMethod]
@@ -417,6 +426,10 @@ public void DeserializeEmptyStringTest() =>
         [ExpectedException(typeof(ObjectDisposedException))]
         public void CannotGetActiveCountAfterDisposeTest() => _ = GetDisposedMessage().ActiveCount;
 
+        [TestMethod]
+        [ExpectedException(typeof(ObjectDisposedException))]
+        public void CannotGetFieldCountAfterDisposeTest() => _ = GetDisposedMessage().FieldCount;
+
         [TestMethod]
         [ExpectedException(typeof(ObjectDisposedException))]
         public void CannotGetUtf8ValidationAfterDisposeTest() => _ = GetDisposedMessage().Utf8Validation;
@@ -504,7 +517,7 @@ static void CatchObjectDisposedException(Action action)
         }
 
         [TestMethod]
-        public unsafe void CannotSetPropertyWhenNativeFunctionIsMissingTest()
+        public unsafe void MemberThrowsWhenNativeFunctionIsMissingTest()
         {
             NativeImplementation nativeImplementation = new(default);
             nativeImplementation.mdf_message_set_property = default;
@@ -517,6 +530,7 @@ public unsafe void CannotSetPropertyWhenNativeFunctionIsMissingTest()
             nativeImplementation.mdf_message_move = default;
             nativeImplementation.mdf_message_serialize = default;
             nativeImplementation.mdf_message_deserialize = default;
+            nativeImplementation.mdf_message_get_num_fields = default;
 
             using Message message = new(nativeImplementation);
             CatchInvalidOperationException(() => message.CompressionLevel = CompressionLevel.Z_BEST_COMPRESSION, nameof(nativeImplementation.mdf_message_set_property));
@@ -539,8 +553,7 @@ public unsafe void CannotSetPropertyWhenNativeFunctionIsMissingTest()
             CatchInvalidOperationException(() => message.Serialize(out _), nameof(nativeImplementation.mdf_message_serialize));
             CatchInvalidOperationException(() => message.Deserialize("..."), nameof(nativeImplementation.mdf_message_deserialize));
             CatchInvalidOperationException(() => message.Deserialize(default(ReadOnlySpan<byte>)), nameof(nativeImplementation.mdf_message_deserialize));
-
-
+            CatchInvalidOperationException(() => _ = message.FieldCount, nameof(nativeImplementation.mdf_message_get_num_fields));
 
             static void CatchInvalidOperationException(Action action, string missingFunctionName)
             {

Tests/Millistream.Streaming.UnitTests/Millistream.Streaming/Interop/INativeImplementation.cs

@@ -40,6 +40,7 @@ public interface INativeImplementation
         int mdf_message_serialize(IntPtr message, ref IntPtr result);
         int mdf_message_deserialize(IntPtr message, IntPtr data);
         int mdf_message_set_property(IntPtr message, int option, int value);
+        int mdf_message_get_num_fields(IntPtr message);
 #pragma warning restore IDE1006
     }
 }

Tests/Millistream.Streaming.UnitTests/Millistream.Streaming/Interop/NativeImplementation.cs

@@ -41,6 +41,7 @@ internal unsafe class NativeImplementation
         internal delegate*<IntPtr, ref IntPtr, int> mdf_message_serialize;
         internal delegate*<IntPtr, IntPtr, int> mdf_message_deserialize;
         internal delegate*<IntPtr, MDF_MSG_OPTION, int, int> mdf_message_set_property;
+        internal delegate*<IntPtr, int> mdf_message_get_num_fields;
 
         internal static NativeImplementation Default => s_defaultImplementation ??= new(null);
         internal static INativeImplementation Implementation { get; set; }
@@ -85,6 +86,7 @@ internal NativeImplementation(string _)
             mdf_message_serialize = &MdfMessageSerialize;
             mdf_message_deserialize = &MdfMessageDeserialize;
             mdf_message_set_property = &MdfMessageSetProperty;
+            mdf_message_get_num_fields = &MdfMessageGetNumFields;
         }
 
         private static IntPtr MdfCreate() => Implementation.mdf_create();
@@ -122,5 +124,6 @@ internal NativeImplementation(string _)
         private static int MdfMessageSerialize(IntPtr message, ref IntPtr result) => Implementation.mdf_message_serialize(message, ref result);
         private static int MdfMessageDeserialize(IntPtr message, IntPtr data) => Implementation.mdf_message_deserialize(message, data);
         private static int MdfMessageSetProperty(IntPtr message, MDF_MSG_OPTION option, int value) => Implementation.mdf_message_set_property(message, (int)option, value);
+        private static int MdfMessageGetNumFields(IntPtr message) => Implementation.mdf_message_get_num_fields(message);
     }
 }