Base type safety in C#. Clear FlatBufferBuilder in C#.

net/FlatBuffers/ByteBuffer.cs

@@ -41,6 +41,11 @@ namespace FlatBuffers
             _pos = 0;
         }
 
+        public void Reset()
+        {
+            _pos = 0;
+        }
+
         public int Position { get { return _pos; } }
 
         // Pre-allocated helper arrays for convertion.

net/FlatBuffers/FlatBufferBuilder.cs

@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright 2014 Google Inc. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -49,6 +49,17 @@ namespace FlatBuffers
             _bb = new ByteBuffer(new byte[initialSize]);
         }
 
+        public void Clear()
+        {
+            _space = _bb.Length;
+            _bb.Reset();
+            _minAlign = 1;
+            _vtable = null;
+            _objectStart = 0;
+            _vtables = new int[16];
+            _numVtables = 0;
+            _vectorNumElems = 0;
+        }
 
         public int Offset { get { return _bb.Length - _space; } }
 
@@ -196,10 +207,10 @@ namespace FlatBuffers
             Prep(alignment, elemSize * count); // Just in case alignment > int.
         }
 
-        public int EndVector()
+        public VectorOffset EndVector()
         {
             PutInt(_vectorNumElems);
-            return Offset;
+            return new VectorOffset(Offset);
         }
 
         public void Nested(int obj)
@@ -250,7 +261,7 @@ namespace FlatBuffers
         public void AddDouble(int o, double x, double d) { if (x != d) { AddDouble(x); Slot(o); } }
         public void AddOffset(int o, int x, int d) { if (x != d) { AddOffset(x); Slot(o); } }
 
-        public int CreateString(string s)
+        public StringOffset CreateString(string s)
         {
             NotNested();
             byte[] utf8 = Encoding.UTF8.GetBytes(s);
@@ -258,7 +269,7 @@ namespace FlatBuffers
             StartVector(1, utf8.Length, 1);
             Buffer.BlockCopy(utf8, 0, _bb.Data, _space -= utf8.Length,
                              utf8.Length);
-            return EndVector();
+            return new StringOffset(EndVector().Value);
         }
 
         // Structs are stored inline, so nothing additional is being added.

net/FlatBuffers/FlatBuffers.csproj

@@ -37,6 +37,7 @@
     <Compile Include="ByteBuffer.cs" />
     <Compile Include="FlatBufferBuilder.cs" />
     <Compile Include="FlatBufferConstants.cs" />
+    <Compile Include="Offset.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Struct.cs" />
     <Compile Include="Table.cs" />

net/FlatBuffers/Offset.cs

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2014 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace FlatBuffers
+{
+    /// <summary>
+    /// Offset class for typesafe assignments.
+    /// </summary>
+    public struct Offset<T> where T : class
+    {
+        public int Value;
+        public Offset(int value)
+        {
+            Value = value;
+        }
+    }
+
+    public struct StringOffset
+    {
+        public int Value;
+        public StringOffset(int value)
+        {
+            Value = value;
+        }
+    }
+
+    public struct VectorOffset
+    {
+        public int Value;
+        public VectorOffset(int value)
+        {
+            Value = value;
+        }
+    }
+}