release v3.0.3

## Nino.Serialization v3.0.3
- [Fix] Consists serialization strategy for unmanaged polymorphic structs
- [Fix] Fix Unity unable to serialize unmanaged list correctly
- [Fix] Add check endianness to ensure collection can be serialized appropriately on big endian architectures

src/Nino.Core/Reader.cs

@@ -32,6 +32,10 @@ public bool ReadCollectionHeader(out int length)
 
             //if value is 0 or sign bit is not set, then it's a null collection
             Read(out uint value);
+#if BIGENDIAN
+            length = (int)(value & 0x7FFFFFFF);
+            return true;
+#else
 #if NET5_0_OR_GREATER
             value = System.Buffers.Binary.BinaryPrimitives.ReverseEndianness(value);
 #else
@@ -40,6 +44,7 @@ public bool ReadCollectionHeader(out int length)
 #endif
             length = (int)(value & 0x7FFFFFFF);
             return true;
+#endif
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]

src/Nino.Core/TypeCollector.cs

@@ -15,11 +15,15 @@ public static uint GetCollectionHeader(int size)
         {
             // set sign bit to 1 - indicates that this is a collection and not null
             uint ret = (uint)size | 0x80000000;
+#if BIGENDIAN
+            return ret;
+#else
             //to big endian
 #if NET5_0_OR_GREATER
             return System.Buffers.Binary.BinaryPrimitives.ReverseEndianness(ret);
 #else
             return (ret << 24) | (ret >> 24) | ((ret & 0x0000FF00) << 8) | ((ret & 0x00FF0000) >> 8);
+#endif
 #endif
         }
 

src/Nino.Core/Writer.cs

@@ -97,22 +97,29 @@ public void Write<T>(List<T> value) where T : unmanaged
                 Write(TypeCollector.NullCollection);
                 return;
             }
-            
+
 #if NET6_0_OR_GREATER
             Write(CollectionsMarshal.AsSpan(value));
 #else
             ref var lst = ref Unsafe.As<List<T>, TypeCollector.ListView<T>>(ref value);
-            Write(lst._items);
+            Write(lst._items.AsSpan(0, lst._size));
 #endif
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Write<T>(List<T?> value) where T : unmanaged
         {
+            if (value == null)
+            {
+                Write(TypeCollector.NullCollection);
+                return;
+            }
+
 #if NET6_0_OR_GREATER
             Write(CollectionsMarshal.AsSpan(value));
 #else
-            Write((ICollection<T>)value);
+            ref var lst = ref Unsafe.As<List<T?>, TypeCollector.ListView<T?>>(ref value);
+            Write(lst._items.AsSpan(0, lst._size));
 #endif
         }