fix: encode versional size position

Author: Jooty

src/Imcodec.ObjectProperty/Property.cs

@@ -159,7 +159,7 @@ private static bool EncodeElement(BitWriter writer, ObjectSerializer serializer,
             return Property<T>.EncodeEnum(writer, val!, serializer);
         }
         else if (StreamPropertyCodec.TryGetWriter(InnerType, out var codec)) {
-            codec.Invoke(writer, (T) val!);
+            codec.Invoke(writer, val!);
 
             return true;
         }

src/Imcodec.ObjectProperty/PropertyClass.cs

@@ -133,6 +133,7 @@ internal bool Decode(BitReader reader, ObjectSerializer serializer) {
     }
 
     private bool EncodeVersionable(BitWriter writer, ObjectSerializer serializer) {
+        var objectStart = writer.BitPos();
         writer.WriteUInt32(0); // Placeholder for the size.
 
         foreach (var property in Properties) {
@@ -141,27 +142,25 @@ private bool EncodeVersionable(BitWriter writer, ObjectSerializer serializer) {
             }
 
             // Write the hash and size of the property.
+            var sizeStart = writer.BitPos();
             writer.WriteUInt32(0); // Placeholder for the size.
             writer.WriteUInt32(property.Hash);
 
-            var sizeBitPos = writer.BitPos();
+            var preEncodeBitPos = writer.BitPos();
             var encodeSuccess = property.Encode(writer, serializer);
-            if (!encodeSuccess) {
-                return false;
-            }
 
             // Write the size of the property.
-            var size = writer.BitPos() - sizeBitPos;
-            writer.SeekBit(sizeBitPos);
+            var size = writer.BitPos() - preEncodeBitPos;
+            writer.SeekBit(sizeStart);
             writer.WriteUInt32((uint)size);
-            writer.SeekBit(sizeBitPos + size);
+            writer.SeekBit(preEncodeBitPos + size);
         }
 
         // Write the size of the object.
-        var objectSize = writer.BitPos();
-        writer.SeekBit(0);
+        var objectSize = writer.BitPos() - objectStart;
+        writer.SeekBit(objectStart);
         writer.WriteUInt32((uint)objectSize);
-        writer.SeekBit(objectSize);
+        writer.SeekBit(objectStart + objectSize);
 
         return true;
     }
@@ -180,6 +179,11 @@ private bool DecodeVersionable(BitReader reader, ObjectSerializer serializer) {
             var propertySize = reader.ReadUInt32();
             var propertyHash = reader.ReadUInt32();
 
+            // A property size of 0 would cause an infinite loop.
+            if (propertySize == 0) {
+                return false;
+            }
+
             // Ensure that the property exists. If it does, decode it.
             if (propMap.TryGetValue(propertyHash, out var property)) {
                 property.Decode(reader, serializer);