Changed lobby & chatMsg IDs to from uint to ushort, added a utility class that handles the wrap around of IDs

2017-02-05 22:55:19 +02:00
parent 9bda79036a
commit 4b8d1054b1
7 changed files with 94 additions and 42 deletions
--- a/Subsurface/Source/Networking/NetIdUtils.cs
+++ b/Subsurface/Source/Networking/NetIdUtils.cs
@@ -0,0 +1,57 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Barotrauma.Networking
+{
+    static class NetIdUtils
+    {
+        /// <summary>
+        /// Is newID more recent than oldID
+        /// </summary>
+        public static bool IdMoreRecent(ushort newID, ushort oldID)
+        {
+            uint id1 = newID;
+            uint id2 = oldID;
+
+            return
+                (id1 > id2) && (id1 - id2 <= ushort.MaxValue / 2)
+                   ||
+                (id2 > id1) && (id2 - id1 > ushort.MaxValue / 2);
+        }
+
+        public static ushort Clamp(ushort id, ushort min, ushort max)
+        {
+            if (IdMoreRecent(min, max))
+            {
+                throw new ArgumentException("Min cannot be larger than max");
+            }
+
+            if (!IdMoreRecent(id, min))
+            {
+                return min;
+            }
+            else if (IdMoreRecent(id, max))
+            {
+                return max;
+            }
+
+            return id;
+        }
+
+#if DEBUG
+        public static void Test()
+        {
+            Debug.Assert(NetIdUtils.IdMoreRecent((ushort)2, (ushort)1));
+            Debug.Assert(NetIdUtils.IdMoreRecent((ushort)2, (ushort)(ushort.MaxValue - 5)));
+            Debug.Assert(!NetIdUtils.IdMoreRecent((ushort)ushort.MaxValue, (ushort)5));
+
+            Debug.Assert(Clamp((ushort)5, (ushort)1, (ushort)10) == 5);
+            Debug.Assert(Clamp((ushort)(ushort.MaxValue - 5), (ushort)(ushort.MaxValue - 2), (ushort)3) == (ushort)(ushort.MaxValue - 2));
+        }
+#endif
+    }
+}