Fix bug in data encoder where MSB of 128 and 0 value bytes was errone…

…ously being flipped

EOLib.IO/NumericConstants.cs

@@ -6,8 +6,8 @@ namespace EOLib.IO
     public static class NumericConstants
     {
         public const int ONE_BYTE_MAX = 253;
-        public const int TWO_BYTE_MAX = 64009;
-        public const int THREE_BYTE_MAX = 16194277;
+        public const int TWO_BYTE_MAX = ONE_BYTE_MAX * ONE_BYTE_MAX;
+        public const int THREE_BYTE_MAX = ONE_BYTE_MAX * ONE_BYTE_MAX * ONE_BYTE_MAX;
 
         public static readonly int[] NUMERIC_MAXIMUM = {ONE_BYTE_MAX, TWO_BYTE_MAX, THREE_BYTE_MAX };
     }

EOLib.IO/Services/DataEncoderService.cs

@@ -59,7 +59,7 @@ public List<byte> Deinterleave(IReadOnlyList<byte> data)
 
         public List<byte> FlipMSB(IReadOnlyList<byte> data)
         {
-            return data.Select(x => (byte)(x ^ 0x80u)).ToList();
+            return data.Select(x => (byte)(x == 128 || x == 0 ? x : x ^ 0x80u)).ToList();
         }
 
         public List<byte> SwapMultiples(IReadOnlyList<byte> data, int multi)

EOLib.Test/Net/PacketEncoderServiceTest.cs

@@ -0,0 +1,45 @@
+using EOLib.Domain.Interact.Quest;
+using EOLib.IO.Services;
+using EOLib.Net;
+using EOLib.Net.PacketProcessing;
+using NUnit.Framework;
+
+namespace EOLib.IO.Test.Services
+{
+    [TestFixture]
+    public class PacketEncoderServiceTest
+    {
+        [Test]
+        public void PacketEncoderService_Encode_127Byte_DoesNotProduceAny0ValueBytes()
+        {
+            var svc = new PacketEncoderService(new NumberEncoderService(), new DataEncoderService());
+
+            var packet = new PacketBuilder(PacketFamily.Quest, PacketAction.Accept)
+                .AddShort(0)
+                .AddShort(0)
+                .AddShort(111)
+                .AddShort(127)
+                .AddChar((byte)DialogReply.Link)
+                .AddChar(1)
+                .Build();
+
+            var encoded = svc.Encode(packet, 5);
+
+            Assert.That(encoded, Has.All.Not.EqualTo(0));
+        }
+
+        [Test]
+        public void PacketEncoderService_Encode_0Byte_DoesNotProduceAny128ValueBytes()
+        {
+            var svc = new PacketEncoderService(new NumberEncoderService(), new DataEncoderService());
+
+            var packet = new PacketBuilder(PacketFamily.Quest, PacketAction.Accept)
+                .AddByte(0)
+                .Build();
+
+            var encoded = svc.Encode(packet, 5);
+
+            Assert.That(encoded, Has.All.Not.EqualTo(128));
+        }
+    }
+}