Java/C#/Python prefixed size support (#4445)

* initial changes to support size prefixed buffers in Java

* add slice equivalent to CSharp ByteBuffer

* resolve TODO for slicing in CSharp code generation

* add newly generated Java and CSharp test sources

* fix typo in comment

* add FinishSizePrefixed methods to CSharp FlatBufferBuilder as well

* add option to allow writing the prefix as well

* generate size-prefixed monster binary as well

* extend JavaTest to test the size prefixed binary as well

* use constants for size prefix length

* fuse common code for getRootAs and getSizePrefixedRootAs

* pulled file identifier out of if

* add FinishSizePrefixed, GetSizePrefixedRootAs support for Python

* Revert "extend JavaTest to test the size prefixed binary as well"

This reverts commit 68be4420dda47e8d0600bb19691f03be71503a68.

* Revert "generate size-prefixed monster binary as well"

This reverts commit 2939516fdf78df4f061c627221e232b312301417.

* fix ByteBuffer.cs Slice() method; add proper CSharp and Java tests

* fix unused parameter

* increment version number

* pulled out generated methods into separate utility class

* pulled out generated methods into separate utility class for Python

* fix indentation

* remove unnecessary comment

* fix newline and copyright

* add ByteBufferUtil to csproj compilation

* hide ByteBuffer's internal data; track offset into parent's array

* test unsafe versions as well; compile and run in debug mode

* clarify help text for size prefix

* move ByteBuffer slicing behavior to subclass

* fix protection levels

* add size prefix support for text generation

* add ByteBufferSlice to csproj compilation

* revert size prefix handling for nested buffers

* use duplicate instead of slice for removing size prefix

* remove slice subclass and use duplicate for removing size prefix

* remove slice specific tests

* remove superfluous command line option
diff --git a/tests/FlatBuffers.Test/ByteBufferTests.cs b/tests/FlatBuffers.Test/ByteBufferTests.cs
index 3324f12..58bd71e 100644
--- a/tests/FlatBuffers.Test/ByteBufferTests.cs
+++ b/tests/FlatBuffers.Test/ByteBufferTests.cs
@@ -44,8 +44,7 @@
         [FlatBuffersTestMethod]
         public void ByteBuffer_PutByteCannotPutAtOffsetPastLength()
         {
-            var buffer = new byte[1];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(1);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.PutByte(1, 99));
         }
 #endif
@@ -66,8 +65,7 @@
         [FlatBuffersTestMethod]
         public void ByteBuffer_PutShortCannotPutAtOffsetPastLength()
         {
-            var buffer = new byte[2];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(2);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.PutShort(2, 99));
         }
 #endif
@@ -76,16 +74,14 @@
         [FlatBuffersTestMethod]
         public void ByteBuffer_PutShortChecksLength()
         {
-            var buffer = new byte[1];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(1);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.PutShort(0, 99));
         }
 
         [FlatBuffersTestMethod]
         public void ByteBuffer_PutShortChecksLengthAndOffset()
         {
-            var buffer = new byte[2];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(2);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.PutShort(1, 99));
         }
 #endif
@@ -108,24 +104,21 @@
         [FlatBuffersTestMethod]
         public void ByteBuffer_PutIntCannotPutAtOffsetPastLength()
         {
-            var buffer = new byte[4];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(4);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.PutInt(2, 0x0A0B0C0D));
         }
 
         [FlatBuffersTestMethod]
         public void ByteBuffer_PutIntChecksLength()
         {
-            var buffer = new byte[1];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(1);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.PutInt(0, 0x0A0B0C0D));
         }
 
         [FlatBuffersTestMethod]
         public void ByteBuffer_PutIntChecksLengthAndOffset()
         {
-            var buffer = new byte[4];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(4);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.PutInt(2, 0x0A0B0C0D));
         }
 #endif
@@ -152,24 +145,21 @@
         [FlatBuffersTestMethod]
         public void ByteBuffer_PutLongCannotPutAtOffsetPastLength()
         {
-            var buffer = new byte[8];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(8);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.PutLong(2, 0x010203040A0B0C0D));
         }
 
         [FlatBuffersTestMethod]
         public void ByteBuffer_PutLongChecksLength()
         {
-            var buffer = new byte[1];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(1);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.PutLong(0, 0x010203040A0B0C0D));
         }
 
         [FlatBuffersTestMethod]
         public void ByteBuffer_PutLongChecksLengthAndOffset()
         {
-            var buffer = new byte[8];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(8);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.PutLong(2, 0x010203040A0B0C0D));
         }
 #endif
@@ -187,8 +177,7 @@
         [FlatBuffersTestMethod]
         public void ByteBuffer_GetByteChecksOffset()
         {
-            var buffer = new byte[1];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(1);
             Assert.Throws<ArgumentOutOfRangeException>(()=>uut.Get(1));
         }
 #endif
@@ -207,16 +196,14 @@
         [FlatBuffersTestMethod]
         public void ByteBuffer_GetShortChecksOffset()
         {
-            var buffer = new byte[2];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(2);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.GetShort(2));
         }
 
         [FlatBuffersTestMethod]
         public void ByteBuffer_GetShortChecksLength()
         {
-            var buffer = new byte[2];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(2);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.GetShort(1));
         }
 #endif
@@ -237,16 +224,14 @@
         [FlatBuffersTestMethod]
         public void ByteBuffer_GetIntChecksOffset()
         {
-            var buffer = new byte[4];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(4);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.GetInt(4));
         }
 
         [FlatBuffersTestMethod]
         public void ByteBuffer_GetIntChecksLength()
         {
-            var buffer = new byte[2];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(2);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.GetInt(0));
         }
 #endif
@@ -271,16 +256,14 @@
         [FlatBuffersTestMethod]
         public void ByteBuffer_GetLongChecksOffset()
         {
-            var buffer = new byte[8];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(8);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.GetLong(8));
         }
 
         [FlatBuffersTestMethod]
         public void ByteBuffer_GetLongChecksLength()
         {
-            var buffer = new byte[7];
-            var uut = new ByteBuffer(buffer);
+            var uut = new ByteBuffer(7);
             Assert.Throws<ArgumentOutOfRangeException>(() => uut.GetLong(0));
         }
 #endif
@@ -317,5 +300,49 @@
             var rereverse = ByteBuffer.ReverseBytes(reverse);
             Assert.AreEqual(original, rereverse);
         }
+
+        [FlatBuffersTestMethod]
+        public void ByteBuffer_ToFullArray_MatchesBuffer()
+        {
+            var buffer = new byte[4];
+            buffer[0] = 0x0D;
+            buffer[1] = 0x0C;
+            buffer[2] = 0x0B;
+            buffer[3] = 0x0A;
+            var uut = new ByteBuffer(buffer);
+            Assert.ArrayEqual(buffer, uut.ToFullArray());
+        }
+
+        [FlatBuffersTestMethod]
+        public void ByteBuffer_ToSizedArray_MatchesBuffer()
+        {
+            var buffer = new byte[4];
+            buffer[0] = 0x0D;
+            buffer[1] = 0x0C;
+            buffer[2] = 0x0B;
+            buffer[3] = 0x0A;
+            var uut = new ByteBuffer(buffer);
+            Assert.ArrayEqual(buffer, uut.ToFullArray());
+        }
+
+        [FlatBuffersTestMethod]
+        public void ByteBuffer_Duplicate_MatchesBuffer()
+        {
+            var buffer = new byte[4];
+            buffer[0] = 0x0D;
+            buffer[1] = 0x0C;
+            buffer[2] = 0x0B;
+            buffer[3] = 0x0A;
+            var uut = new ByteBuffer(buffer);
+            Assert.AreEqual(0x0A0B0C0D, uut.GetInt(0));
+
+            // Advance by two bytes
+            uut.Position = 2; uut = uut.Duplicate();
+            Assert.AreEqual(0x0A0B, uut.GetShort(2));
+
+            // Advance by one more byte
+            uut.Position = 1; uut = uut.Duplicate();
+            Assert.AreEqual(0x0A, uut.Get(3));
+        }
     }
 }
diff --git a/tests/FlatBuffers.Test/FlatBuffers.Test.csproj b/tests/FlatBuffers.Test/FlatBuffers.Test.csproj
index 38d62d6..7c67274 100644
--- a/tests/FlatBuffers.Test/FlatBuffers.Test.csproj
+++ b/tests/FlatBuffers.Test/FlatBuffers.Test.csproj
@@ -41,6 +41,9 @@
     <Compile Include="..\..\net\FlatBuffers\ByteBuffer.cs">
       <Link>FlatBuffers\ByteBuffer.cs</Link>
     </Compile>
+    <Compile Include="..\..\net\FlatBuffers\ByteBufferUtil.cs">
+      <Link>FlatBuffers\ByteBufferUtil.cs</Link>
+    </Compile>
     <Compile Include="..\..\net\FlatBuffers\IFlatbufferObject.cs">
       <Link>FlatBuffers\IFlatbufferObject.cs</Link>
     </Compile>
diff --git a/tests/FlatBuffers.Test/FlatBuffersExampleTests.cs b/tests/FlatBuffers.Test/FlatBuffersExampleTests.cs
index ccd5b05..82d4fdf 100644
--- a/tests/FlatBuffers.Test/FlatBuffersExampleTests.cs
+++ b/tests/FlatBuffers.Test/FlatBuffersExampleTests.cs
@@ -33,6 +33,12 @@
         [FlatBuffersTestMethod]
         public void CanCreateNewFlatBufferFromScratch()
         {
+            CanCreateNewFlatBufferFromScratch(true);
+            CanCreateNewFlatBufferFromScratch(false);
+        }
+
+        private void CanCreateNewFlatBufferFromScratch(bool sizePrefix)
+        {
             // Second, let's create a FlatBuffer from scratch in C#, and test it also.
             // We use an initial size of 1 to exercise the reallocation algorithm,
             // normally a size larger than the typical FlatBuffer you generate would be
@@ -95,22 +101,40 @@
             Monster.AddTestarrayoftables(fbb, sortMons);
             var mon = Monster.EndMonster(fbb);
 
-            Monster.FinishMonsterBuffer(fbb, mon);
+            if (sizePrefix)
+            {
+                Monster.FinishSizePrefixedMonsterBuffer(fbb, mon);
+            }
+            else
+            {
+                Monster.FinishMonsterBuffer(fbb, mon);
+            }
 
 
             // Dump to output directory so we can inspect later, if needed
-            using (var ms = new MemoryStream(fbb.DataBuffer.Data, fbb.DataBuffer.Position, fbb.Offset))
+            using (var ms = fbb.DataBuffer.ToMemoryStream(fbb.DataBuffer.Position, fbb.Offset))
             {
                 var data = ms.ToArray();
-                File.WriteAllBytes(@"Resources/monsterdata_cstest.mon",data);
+                string filename = @"Resources/monsterdata_cstest" + (sizePrefix ? "_sp" : "") + ".mon";
+                File.WriteAllBytes(filename, data);
+            }
+
+            // Remove the size prefix if necessary for further testing
+            ByteBuffer dataBuffer = fbb.DataBuffer;
+            if (sizePrefix)
+            {
+                Assert.AreEqual(ByteBufferUtil.GetSizePrefix(dataBuffer) + FlatBufferConstants.SizePrefixLength,
+                                dataBuffer.Length - dataBuffer.Position);
+                dataBuffer = ByteBufferUtil.RemoveSizePrefix(dataBuffer);
             }
 
             // Now assert the buffer
-            TestBuffer(fbb.DataBuffer);
+            TestBuffer(dataBuffer);
 
             //Attempt to mutate Monster fields and check whether the buffer has been mutated properly
             // revert to original values after testing
-            Monster monster = Monster.GetRootAsMonster(fbb.DataBuffer);
+            Monster monster = Monster.GetRootAsMonster(dataBuffer);
+            
 
             // mana is optional and does not exist in the buffer so the mutation should fail
             // the mana field should retain its default value
@@ -161,12 +185,12 @@
             pos.MutateX(1.0f);
             Assert.AreEqual(pos.X, 1.0f);
 
-            TestBuffer(fbb.DataBuffer);
+            TestBuffer(dataBuffer);
         }
 
         private void TestBuffer(ByteBuffer bb)
         {
-            var monster = Monster.GetRootAsMonster(bb);
+            Monster monster = Monster.GetRootAsMonster(bb);
 
             Assert.AreEqual(80, monster.Hp);
             Assert.AreEqual(150, monster.Mana);
diff --git a/tests/FlatBuffers.Test/FlatBuffersFuzzTests.cs b/tests/FlatBuffers.Test/FlatBuffersFuzzTests.cs
index d933246..2d411a2 100644
--- a/tests/FlatBuffers.Test/FlatBuffersFuzzTests.cs
+++ b/tests/FlatBuffers.Test/FlatBuffersFuzzTests.cs
@@ -33,21 +33,21 @@
         public void TestNumbers()
         {
             var builder = new FlatBufferBuilder(1);
-            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.ToFullArray());
             builder.AddBool(true);
-            Assert.ArrayEqual(new byte[] { 1 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 1 }, builder.DataBuffer.ToFullArray());
             builder.AddSbyte(-127);
-            Assert.ArrayEqual(new byte[] { 129, 1 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 129, 1 }, builder.DataBuffer.ToFullArray());
             builder.AddByte(255);
-            Assert.ArrayEqual(new byte[] { 0, 255, 129, 1 }, builder.DataBuffer.Data); // First pad
+            Assert.ArrayEqual(new byte[] { 0, 255, 129, 1 }, builder.DataBuffer.ToFullArray()); // First pad
             builder.AddShort(-32222);
-            Assert.ArrayEqual(new byte[] { 0, 0, 0x22, 0x82, 0, 255, 129, 1 }, builder.DataBuffer.Data); // Second pad
+            Assert.ArrayEqual(new byte[] { 0, 0, 0x22, 0x82, 0, 255, 129, 1 }, builder.DataBuffer.ToFullArray()); // Second pad
             builder.AddUshort(0xFEEE);
-            Assert.ArrayEqual(new byte[] { 0xEE, 0xFE, 0x22, 0x82, 0, 255, 129, 1 }, builder.DataBuffer.Data); // no pad
+            Assert.ArrayEqual(new byte[] { 0xEE, 0xFE, 0x22, 0x82, 0, 255, 129, 1 }, builder.DataBuffer.ToFullArray()); // no pad
             builder.AddInt(-53687092);
-            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 204, 204, 204, 252, 0xEE, 0xFE, 0x22, 0x82, 0, 255, 129, 1 }, builder.DataBuffer.Data); // third pad
+            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 204, 204, 204, 252, 0xEE, 0xFE, 0x22, 0x82, 0, 255, 129, 1 }, builder.DataBuffer.ToFullArray()); // third pad
             builder.AddUint(0x98765432);
-            Assert.ArrayEqual(new byte[] { 0x32, 0x54, 0x76, 0x98, 204, 204, 204, 252, 0xEE, 0xFE, 0x22, 0x82, 0, 255, 129, 1 }, builder.DataBuffer.Data); // no pad
+            Assert.ArrayEqual(new byte[] { 0x32, 0x54, 0x76, 0x98, 204, 204, 204, 252, 0xEE, 0xFE, 0x22, 0x82, 0, 255, 129, 1 }, builder.DataBuffer.ToFullArray()); // no pad
         }
 
         [FlatBuffersTestMethod]
@@ -55,11 +55,11 @@
         {
             var builder = new FlatBufferBuilder(1);
             builder.AddUlong(0x1122334455667788);
-            Assert.ArrayEqual(new byte[] { 0x88, 0x77, 0x66, 0x55, 0x44, 0x33, 0x22, 0x11 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0x88, 0x77, 0x66, 0x55, 0x44, 0x33, 0x22, 0x11 }, builder.DataBuffer.ToFullArray());
 
             builder = new FlatBufferBuilder(1);
             builder.AddLong(0x1122334455667788);
-            Assert.ArrayEqual(new byte[] { 0x88, 0x77, 0x66, 0x55, 0x44, 0x33, 0x22, 0x11 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0x88, 0x77, 0x66, 0x55, 0x44, 0x33, 0x22, 0x11 }, builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -67,11 +67,11 @@
         {
             var builder = new FlatBufferBuilder(1);
             builder.StartVector(sizeof(byte), 1, 1);
-            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0 }, builder.DataBuffer.ToFullArray());
             builder.AddByte(1);
-            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 1, 0, 0, 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 1, 0, 0, 0 }, builder.DataBuffer.ToFullArray());
             builder.EndVector();
-            Assert.ArrayEqual(new byte[] { 1, 0, 0, 0, 1, 0, 0, 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 1, 0, 0, 0, 1, 0, 0, 0 }, builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -79,13 +79,13 @@
         {
             var builder = new FlatBufferBuilder(1);
             builder.StartVector(sizeof(byte), 2, 1);
-            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0 }, builder.DataBuffer.ToFullArray());
             builder.AddByte(1);
-            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0, 1, 0, 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0, 1, 0, 0 }, builder.DataBuffer.ToFullArray());
             builder.AddByte(2);
-            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 2, 1, 0, 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 2, 1, 0, 0 }, builder.DataBuffer.ToFullArray());
             builder.EndVector();
-            Assert.ArrayEqual(new byte[] { 2, 0, 0, 0, 2, 1, 0, 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 2, 0, 0, 0, 2, 1, 0, 0 }, builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -93,11 +93,11 @@
         {
             var builder = new FlatBufferBuilder(1);
             builder.StartVector(sizeof(ushort), 1, 1);
-            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0 }, builder.DataBuffer.ToFullArray());
             builder.AddUshort(1);
-            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 1, 0, 0, 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 1, 0, 0, 0 }, builder.DataBuffer.ToFullArray());
             builder.EndVector();
-            Assert.ArrayEqual(new byte[] { 1, 0, 0, 0, 1, 0, 0, 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 1, 0, 0, 0, 1, 0, 0, 0 }, builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -105,13 +105,13 @@
         {
             var builder = new FlatBufferBuilder(1);
             builder.StartVector(sizeof(ushort), 2, 1);
-            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0 }, builder.DataBuffer.ToFullArray());
             builder.AddUshort(0xABCD);
-            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0, 0, 0xCD, 0xAB }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0, 0, 0xCD, 0xAB }, builder.DataBuffer.ToFullArray());
             builder.AddUshort(0xDCBA);
-            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0xBA, 0xDC, 0xCD, 0xAB }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0, 0, 0, 0, 0xBA, 0xDC, 0xCD, 0xAB }, builder.DataBuffer.ToFullArray());
             builder.EndVector();
-            Assert.ArrayEqual(new byte[] { 2, 0, 0, 0, 0xBA, 0xDC, 0xCD, 0xAB }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 2, 0, 0, 0, 0xBA, 0xDC, 0xCD, 0xAB }, builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -119,7 +119,7 @@
         {
             var builder = new FlatBufferBuilder(1);
             builder.CreateString("foo");
-            Assert.ArrayEqual(new byte[] { 3, 0, 0, 0, (byte)'f', (byte)'o', (byte)'o', 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 3, 0, 0, 0, (byte)'f', (byte)'o', (byte)'o', 0 }, builder.DataBuffer.ToFullArray());
 
             builder.CreateString("moop");
             Assert.ArrayEqual(new byte[]
@@ -132,7 +132,7 @@
                 0, 0, 0, 0, // zero terminator with 3 byte pad
                 3, 0, 0, 0,
                 (byte)'f', (byte)'o', (byte)'o', 0
-            }, builder.DataBuffer.Data);
+            }, builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -144,7 +144,7 @@
             {
                 3, 0, 0, 0,
                 0x01, 0x02, 0x03, 0
-            }, builder.DataBuffer.Data); // No padding
+            }, builder.DataBuffer.ToFullArray()); // No padding
             builder.CreateString("\x04\x05\x06\x07");
             Assert.ArrayEqual(new byte[]
             {
@@ -156,7 +156,7 @@
                 0, 0, 0, 0, // zero terminator with 3 byte pad
                 3, 0, 0, 0,
                 0x01, 0x02, 0x03, 0
-            }, builder.DataBuffer.Data); // No padding
+            }, builder.DataBuffer.ToFullArray()); // No padding
         }
 
         [FlatBuffersTestMethod]
@@ -164,14 +164,14 @@
         {
             var builder = new FlatBufferBuilder(1);
             builder.StartObject(0);
-            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.ToFullArray());
             builder.EndObject();
             Assert.ArrayEqual(new byte[]
             {
                 4, 0, 4, 0,
                 4, 0, 0, 0
             },
-                builder.DataBuffer.Data);
+                builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -179,7 +179,7 @@
         {
             var builder = new FlatBufferBuilder(1);
             builder.StartObject(1);
-            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.ToFullArray());
             builder.AddBool(0, true, false);
             builder.EndObject();
             Assert.ArrayEqual(new byte[]
@@ -192,7 +192,7 @@
                 0, 0, 0, // padding
                 1, // value 0
             },
-                builder.DataBuffer.Data);
+                builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -200,7 +200,7 @@
         {
             var builder = new FlatBufferBuilder(1);
             builder.StartObject(1);
-            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.ToFullArray());
             builder.AddBool(0, false, false);
             builder.EndObject();
             Assert.ArrayEqual(new byte[]
@@ -211,7 +211,7 @@
                 // entry 0 is not stored (trimmed end of vtable)
                 4, 0, 0, 0, // int32 offset for start of vtable
             },
-                builder.DataBuffer.Data);
+                builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -219,7 +219,7 @@
         {
             var builder = new FlatBufferBuilder(1);
             builder.StartObject(1);
-            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.ToFullArray());
             builder.AddShort(0, 0x789A, 0);
             builder.EndObject();
             Assert.ArrayEqual(new byte[]
@@ -232,7 +232,7 @@
                 0, 0, // padding
                 0x9A, 0x78, //value 0
             },
-                builder.DataBuffer.Data);
+                builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -240,7 +240,7 @@
         {
             var builder = new FlatBufferBuilder(1);
             builder.StartObject(2);
-            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.ToFullArray());
             builder.AddShort(0, 0x3456, 0);
             builder.AddShort(1, 0x789A, 0);
             builder.EndObject();
@@ -254,7 +254,7 @@
                 0x9A, 0x78, // value 1
                 0x56, 0x34, // value 0
             },
-                builder.DataBuffer.Data);
+                builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -262,7 +262,7 @@
         {
             var builder = new FlatBufferBuilder(1);
             builder.StartObject(2);
-            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.Data);
+            Assert.ArrayEqual(new byte[] { 0 }, builder.DataBuffer.ToFullArray());
             builder.AddShort(0, 0x3456, 0);
             builder.AddBool(1, true, false);
             builder.EndObject();
@@ -276,7 +276,7 @@
                 0, 1, // padding + value 1
                 0x56, 0x34, // value 0
             },
-                builder.DataBuffer.Data);
+                builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -303,7 +303,7 @@
                 4, 0, 0, 0,
                 0, 0, 0, 0,
             },
-                builder.DataBuffer.Data);
+                builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -330,7 +330,7 @@
                 0, 0, 55, 0, // value 0
                 0, 0, 0, 0, // length of vector (not in sctruc)
             },
-                builder.DataBuffer.Data);
+                builder.DataBuffer.ToFullArray());
         }
 
 
@@ -361,7 +361,7 @@
                 0x78, 0x56,       // vector value 0
                 0x34, 0x12,       // vector value 1
             },
-                builder.DataBuffer.Data);
+                builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -391,7 +391,7 @@
                 0x00, 0x00, 0x34, 0x12, // struct value 1
                 0x00, 0x00, 0x00, 55, // struct value 0
             },
-                builder.DataBuffer.Data);
+                builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -425,7 +425,7 @@
                 44, // vector 0, 1
                 33, // vector 0, 0
             },
-                builder.DataBuffer.Data);
+                builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -438,7 +438,7 @@
             var off = builder.EndObject();
             builder.Finish(off);
 
-            Assert.ArrayEqual(new byte[]
+            byte[] padded = new byte[]
             {
                 0, 0, 0, 0,
                 0, 0, 0, 0,
@@ -452,8 +452,13 @@
                 66, 0, // value 1
                 0, 33, // value 0
 
-            },
-                builder.DataBuffer.Data);
+            };
+            Assert.ArrayEqual(padded, builder.DataBuffer.ToFullArray());
+
+            // no padding in sized array
+            byte[] unpadded = new byte[padded.Length - 12];
+            Buffer.BlockCopy(padded, 12, unpadded, 0, unpadded.Length);
+            Assert.ArrayEqual(unpadded, builder.DataBuffer.ToSizedArray());
         }
 
         [FlatBuffersTestMethod]
@@ -504,7 +509,7 @@
                 44, // value 1, 0
                 33,
             },
-                builder.DataBuffer.Data);
+                builder.DataBuffer.ToFullArray());
         }
 
         [FlatBuffersTestMethod]
@@ -519,7 +524,7 @@
             var off = builder.EndObject();
             builder.Finish(off);
 
-            Assert.ArrayEqual(new byte[]
+            byte[] padded = new byte[]
             {
                 0, 0, 0, 0,
                 0, 0, 0, 0,
@@ -546,8 +551,61 @@
                 1, 1, 1, 1,  // values
                 1, 1, 1, 1,
 
-            },
-                builder.DataBuffer.Data);
+            };
+            Assert.ArrayEqual(padded, builder.DataBuffer.ToFullArray());
+
+            // no padding in sized array
+            byte[] unpadded = new byte[padded.Length - 28];
+            Buffer.BlockCopy(padded, 28, unpadded, 0, unpadded.Length);
+            Assert.ArrayEqual(unpadded, builder.DataBuffer.ToSizedArray());
+        }
+
+        [FlatBuffersTestMethod]
+        public void TestBunchOfBoolsSizePrefixed()
+        {
+            var builder = new FlatBufferBuilder(1);
+            builder.StartObject(8);
+            for (var i = 0; i < 8; i++)
+            {
+                builder.AddBool(i, true, false);
+            }
+            var off = builder.EndObject();
+            builder.FinishSizePrefixed(off);
+
+            byte[] padded = new byte[]
+            {
+                0, 0, 0, 0,
+                0, 0, 0, 0,
+                0, 0, 0, 0,
+                0, 0, 0, 0,
+                0, 0, 0, 0,
+                0, 0, 0, 0,      // padding to 64 bytes
+
+                36, 0, 0, 0,     // size prefix
+                24, 0, 0, 0,     // root of table, pointing to vtable offset (obj0)
+                20, 0, // vtable bytes
+                12, 0, // object length
+                11, 0, // start of value 0
+                10, 0, // start of value 1
+                9, 0, // start of value 2
+                8, 0, // start of value 3
+                7, 0, // start of value 4
+                6, 0, // start of value 5
+                5, 0, // start of value 6
+                4, 0, // start of value 7
+
+                20, 0, 0, 0, // int32 offset for start of vtable
+
+                1, 1, 1, 1,  // values
+                1, 1, 1, 1,
+
+            };
+            Assert.ArrayEqual(padded, builder.DataBuffer.ToFullArray());
+
+            // no padding in sized array
+            byte[] unpadded = new byte[padded.Length - 24];
+            Buffer.BlockCopy(padded, 24, unpadded, 0, unpadded.Length);
+            Assert.ArrayEqual(unpadded, builder.DataBuffer.ToSizedArray());
         }
 
         [FlatBuffersTestMethod]
@@ -569,7 +627,7 @@
                 0, 0, 128, 63,  // value
 
             },
-                builder.DataBuffer.Data);
+                builder.DataBuffer.ToFullArray());
         }
 
         private void CheckObjects(int fieldCount, int objectCount)
diff --git a/tests/FlatBuffers.Test/NetTest.sh b/tests/FlatBuffers.Test/NetTest.sh
index ea16e47..6201549 100644
--- a/tests/FlatBuffers.Test/NetTest.sh
+++ b/tests/FlatBuffers.Test/NetTest.sh
@@ -2,8 +2,22 @@
 
 # Testing C# on Linux using Mono.
 
-mcs -out:fbnettest.exe ../../net/FlatBuffers/*.cs ../MyGame/Example/*.cs FlatBuffersTestClassAttribute.cs FlatBuffersTestMethodAttribute.cs Assert.cs FlatBuffersExampleTests.cs Program.cs ByteBufferTests.cs FlatBufferBuilderTests.cs FlatBuffersFuzzTests.cs FuzzTestData.cs Lcg.cs TestTable.cs
-./fbnettest.exe
+mcs -debug -out:./fbnettest.exe \
+  ../../net/FlatBuffers/*.cs ../MyGame/Example/*.cs ../MyGame/*.cs \
+  FlatBuffersTestClassAttribute.cs FlatBuffersTestMethodAttribute.cs Assert.cs FlatBuffersExampleTests.cs Program.cs ByteBufferTests.cs FlatBufferBuilderTests.cs FlatBuffersFuzzTests.cs FuzzTestData.cs Lcg.cs TestTable.cs
+mono --debug ./fbnettest.exe
 rm fbnettest.exe
 rm Resources/monsterdata_cstest.mon
+rm Resources/monsterdata_cstest_sp.mon
+
+# Repeat with unsafe versions
+
+mcs -debug -out:./fbnettest.exe \
+  -unsafe -d:UNSAFE_BYTEBUFFER \
+  ../../net/FlatBuffers/*.cs ../MyGame/Example/*.cs ../MyGame/*.cs \
+  FlatBuffersTestClassAttribute.cs FlatBuffersTestMethodAttribute.cs Assert.cs FlatBuffersExampleTests.cs Program.cs ByteBufferTests.cs FlatBufferBuilderTests.cs FlatBuffersFuzzTests.cs FuzzTestData.cs Lcg.cs TestTable.cs
+mono --debug ./fbnettest.exe
+rm fbnettest.exe
+rm Resources/monsterdata_cstest.mon
+rm Resources/monsterdata_cstest_sp.mon
 
diff --git a/tests/JavaTest.java b/tests/JavaTest.java
index 9a5b676..a9dedf9 100644
--- a/tests/JavaTest.java
+++ b/tests/JavaTest.java
@@ -21,6 +21,8 @@
 import MyGame.Example.*;
 import NamespaceA.*;
 import NamespaceA.NamespaceB.*;
+import com.google.flatbuffers.ByteBufferUtil;
+import static com.google.flatbuffers.Constants.*;
 import com.google.flatbuffers.FlatBufferBuilder;
 
 class JavaTest {
@@ -53,7 +55,8 @@
         // better for performance.
         FlatBufferBuilder fbb = new FlatBufferBuilder(1);
 
-        TestBuilderBasics(fbb);
+        TestBuilderBasics(fbb, true);
+        TestBuilderBasics(fbb, false);
 
         TestExtendedBuffer(fbb.dataBuffer().asReadOnlyBuffer());
 
@@ -244,14 +247,14 @@
 
         FlatBufferBuilder fbb = new FlatBufferBuilder(1, new MappedByteBufferFactory());
 
-        TestBuilderBasics(fbb);
+        TestBuilderBasics(fbb, false);
     }
 
     static void TestSizedInputStream() {
         // Test on default FlatBufferBuilder that uses HeapByteBuffer
         FlatBufferBuilder fbb = new FlatBufferBuilder(1);
 
-        TestBuilderBasics(fbb);
+        TestBuilderBasics(fbb, false);
 
         InputStream in = fbb.sizedInputStream();
         byte[] array = fbb.sizedByteArray();
@@ -271,7 +274,7 @@
         TestEq(count, array.length);
     }
 
-    static void TestBuilderBasics(FlatBufferBuilder fbb) {
+    static void TestBuilderBasics(FlatBufferBuilder fbb, boolean sizePrefix) {
         int[] names = {fbb.createString("Frodo"), fbb.createString("Barney"), fbb.createString("Wilma")};
         int[] off = new int[3];
         Monster.startMonster(fbb);
@@ -321,7 +324,11 @@
         Monster.addTestarrayoftables(fbb, sortMons);
         int mon = Monster.endMonster(fbb);
 
-        Monster.finishMonsterBuffer(fbb, mon);
+        if (sizePrefix) {
+            Monster.finishSizePrefixedMonsterBuffer(fbb, mon);
+        } else {
+            Monster.finishMonsterBuffer(fbb, mon);
+        }
 
         // Write the result to a file for debugging purposes:
         // Note that the binaries are not necessarily identical, since the JSON
@@ -329,7 +336,8 @@
         // Java code. They are functionally equivalent though.
 
         try {
-            FileChannel fc = new FileOutputStream("monsterdata_java_wire.mon").getChannel();
+            String filename = "monsterdata_java_wire" + (sizePrefix ? "_sp" : "") + ".mon";
+            FileChannel fc = new FileOutputStream(filename).getChannel();
             fc.write(fbb.dataBuffer().duplicate());
             fc.close();
         } catch(java.io.IOException e) {
@@ -338,18 +346,24 @@
         }
 
         // Test it:
-        TestExtendedBuffer(fbb.dataBuffer());
+        ByteBuffer dataBuffer = fbb.dataBuffer();
+        if (sizePrefix) {
+            TestEq(ByteBufferUtil.getSizePrefix(dataBuffer) + SIZE_PREFIX_LENGTH,
+                   dataBuffer.remaining());
+            dataBuffer = ByteBufferUtil.removeSizePrefix(dataBuffer);
+        }
+        TestExtendedBuffer(dataBuffer);
 
         // Make sure it also works with read only ByteBuffers. This is slower,
         // since creating strings incurs an additional copy
         // (see Table.__string).
-        TestExtendedBuffer(fbb.dataBuffer().asReadOnlyBuffer());
+        TestExtendedBuffer(dataBuffer.asReadOnlyBuffer());
 
         TestEnums();
 
         //Attempt to mutate Monster fields and check whether the buffer has been mutated properly
         // revert to original values after testing
-        Monster monster = Monster.getRootAsMonster(fbb.dataBuffer());
+        Monster monster = Monster.getRootAsMonster(dataBuffer);
 
         // mana is optional and does not exist in the buffer so the mutation should fail
         // the mana field should retain its default value
diff --git a/tests/MyGame/Example/Monster.cs b/tests/MyGame/Example/Monster.cs
index c554c3c..b7844fb 100644
--- a/tests/MyGame/Example/Monster.cs
+++ b/tests/MyGame/Example/Monster.cs
@@ -203,6 +203,7 @@
     return new Offset<Monster>(o);
   }
   public static void FinishMonsterBuffer(FlatBufferBuilder builder, Offset<Monster> offset) { builder.Finish(offset.Value, "MONS"); }
+  public static void FinishSizePrefixedMonsterBuffer(FlatBufferBuilder builder, Offset<Monster> offset) { builder.FinishSizePrefixed(offset.Value, "MONS"); }
 
   public static VectorOffset CreateSortedVectorOfMonster(FlatBufferBuilder builder, Offset<Monster>[] offsets) {
     Array.Sort(offsets, (Offset<Monster> o1, Offset<Monster> o2) => Table.CompareStrings(Table.__offset(10, o1.Value, builder.DataBuffer), Table.__offset(10, o2.Value, builder.DataBuffer), builder.DataBuffer));
diff --git a/tests/MyGame/Example/Monster.java b/tests/MyGame/Example/Monster.java
index 6048dc7..8a5bb0e 100644
--- a/tests/MyGame/Example/Monster.java
+++ b/tests/MyGame/Example/Monster.java
@@ -228,6 +228,7 @@
     return o;
   }
   public static void finishMonsterBuffer(FlatBufferBuilder builder, int offset) { builder.finish(offset, "MONS"); }
+  public static void finishSizePrefixedMonsterBuffer(FlatBufferBuilder builder, int offset) { builder.finishSizePrefixed(offset, "MONS"); }
 
   @Override
   protected int keysCompare(Integer o1, Integer o2, ByteBuffer _bb) { return compareStrings(__offset(10, o1, _bb), __offset(10, o2, _bb), _bb); }
diff --git a/tests/monster_test.bfbs b/tests/monster_test.bfbs
index 0093def..7605728 100644
--- a/tests/monster_test.bfbs
+++ b/tests/monster_test.bfbs
Binary files differ
diff --git a/tests/namespace_test/namespace_test2_generated.ts b/tests/namespace_test/namespace_test2_generated.ts
index 61cf631..aa623a8 100644
--- a/tests/namespace_test/namespace_test2_generated.ts
+++ b/tests/namespace_test/namespace_test2_generated.ts
@@ -1,6 +1,6 @@
 // automatically generated by the FlatBuffers compiler, do not modify
 
-import * as NS39599748 from "./namespace_test1_generated";
+import * as NS4989953370203581498 from "./namespace_test1_generated";
 /**
  * @constructor
  */
@@ -39,24 +39,24 @@
  * @param {NamespaceA.NamespaceB.TableInNestedNS=} obj
  * @returns {NamespaceA.NamespaceB.TableInNestedNS|null}
  */
-fooTable(obj?:NS39599748.NamespaceA.NamespaceB.TableInNestedNS):NS39599748.NamespaceA.NamespaceB.TableInNestedNS|null {
+fooTable(obj?:NS4989953370203581498.NamespaceA.NamespaceB.TableInNestedNS):NS4989953370203581498.NamespaceA.NamespaceB.TableInNestedNS|null {
   var offset = this.bb!.__offset(this.bb_pos, 4);
-  return offset ? (obj || new NS39599748.NamespaceA.NamespaceB.TableInNestedNS).__init(this.bb!.__indirect(this.bb_pos + offset), this.bb!) : null;
+  return offset ? (obj || new NS4989953370203581498.NamespaceA.NamespaceB.TableInNestedNS).__init(this.bb!.__indirect(this.bb_pos + offset), this.bb!) : null;
 };
 
 /**
  * @returns {NamespaceA.NamespaceB.EnumInNestedNS}
  */
-fooEnum():NS39599748.NamespaceA.NamespaceB.EnumInNestedNS {
+fooEnum():NS4989953370203581498.NamespaceA.NamespaceB.EnumInNestedNS {
   var offset = this.bb!.__offset(this.bb_pos, 6);
-  return offset ? /** @type {NamespaceA.NamespaceB.EnumInNestedNS} */ (this.bb!.readInt8(this.bb_pos + offset)) : NS39599748.NamespaceA.NamespaceB.EnumInNestedNS.A;
+  return offset ? /** @type {NamespaceA.NamespaceB.EnumInNestedNS} */ (this.bb!.readInt8(this.bb_pos + offset)) : NS4989953370203581498.NamespaceA.NamespaceB.EnumInNestedNS.A;
 };
 
 /**
  * @param {NamespaceA.NamespaceB.EnumInNestedNS} value
  * @returns {boolean}
  */
-mutate_foo_enum(value:NS39599748.NamespaceA.NamespaceB.EnumInNestedNS):boolean {
+mutate_foo_enum(value:NS4989953370203581498.NamespaceA.NamespaceB.EnumInNestedNS):boolean {
   var offset = this.bb!.__offset(this.bb_pos, 6);
 
   if (offset === 0) {
@@ -71,9 +71,9 @@
  * @param {NamespaceA.NamespaceB.StructInNestedNS=} obj
  * @returns {NamespaceA.NamespaceB.StructInNestedNS|null}
  */
-fooStruct(obj?:NS39599748.NamespaceA.NamespaceB.StructInNestedNS):NS39599748.NamespaceA.NamespaceB.StructInNestedNS|null {
+fooStruct(obj?:NS4989953370203581498.NamespaceA.NamespaceB.StructInNestedNS):NS4989953370203581498.NamespaceA.NamespaceB.StructInNestedNS|null {
   var offset = this.bb!.__offset(this.bb_pos, 8);
-  return offset ? (obj || new NS39599748.NamespaceA.NamespaceB.StructInNestedNS).__init(this.bb_pos + offset, this.bb!) : null;
+  return offset ? (obj || new NS4989953370203581498.NamespaceA.NamespaceB.StructInNestedNS).__init(this.bb_pos + offset, this.bb!) : null;
 };
 
 /**
@@ -95,8 +95,8 @@
  * @param {flatbuffers.Builder} builder
  * @param {NamespaceA.NamespaceB.EnumInNestedNS} fooEnum
  */
-static addFooEnum(builder:flatbuffers.Builder, fooEnum:NS39599748.NamespaceA.NamespaceB.EnumInNestedNS) {
-  builder.addFieldInt8(1, fooEnum, NS39599748.NamespaceA.NamespaceB.EnumInNestedNS.A);
+static addFooEnum(builder:flatbuffers.Builder, fooEnum:NS4989953370203581498.NamespaceA.NamespaceB.EnumInNestedNS) {
+  builder.addFieldInt8(1, fooEnum, NS4989953370203581498.NamespaceA.NamespaceB.EnumInNestedNS.A);
 };
 
 /**
diff --git a/tests/py_test.py b/tests/py_test.py
index aeef729..1b76b61 100644
--- a/tests/py_test.py
+++ b/tests/py_test.py
@@ -25,6 +25,7 @@
 
 
 from flatbuffers import compat
+from flatbuffers import util
 from flatbuffers.compat import range_func as compat_range
 from flatbuffers.compat import NumpyRequiredForThisFeature
 
@@ -56,9 +57,11 @@
 class TestWireFormat(unittest.TestCase):
     def test_wire_format(self):
         # Verify that using the generated Python code builds a buffer without
-        # returning errors, and is interpreted correctly:
-        gen_buf, gen_off = make_monster_from_generated_code()
-        CheckReadBuffer(gen_buf, gen_off)
+        # returning errors, and is interpreted correctly, for size prefixed
+        # representation and regular:
+        for sizePrefix in [True, False]:
+            gen_buf, gen_off = make_monster_from_generated_code(sizePrefix = sizePrefix)
+            CheckReadBuffer(gen_buf, gen_off, sizePrefix = sizePrefix)
 
         # Verify that the canonical flatbuffer file is readable by the
         # generated Python code. Note that context managers are not part of
@@ -74,7 +77,7 @@
         f.close()
 
 
-def CheckReadBuffer(buf, offset):
+def CheckReadBuffer(buf, offset, sizePrefix = False):
     ''' CheckReadBuffer checks that the given buffer is evaluated correctly
         as the example Monster. '''
 
@@ -83,6 +86,11 @@
         if not stmt:
             raise AssertionError('CheckReadBuffer case failed')
 
+    if sizePrefix:
+        size = util.GetSizePrefix(buf, offset)
+        # taken from the size of monsterdata_python_wire.mon, minus 4
+        asserter(size == 348)
+        buf, offset = util.RemoveSizePrefix(buf, offset)
     monster = MyGame.Example.Monster.Monster.GetRootAsMonster(buf, offset)
 
     asserter(monster.Hp() == 80)
@@ -810,7 +818,7 @@
         ])
 
 
-def make_monster_from_generated_code():
+def make_monster_from_generated_code(sizePrefix = False):
     ''' Use generated code to build the example Monster. '''
 
     b = flatbuffers.Builder(0)
@@ -871,7 +879,10 @@
     MyGame.Example.Monster.MonsterAddVectorOfDoubles(b, VectorOfDoubles)
     mon = MyGame.Example.Monster.MonsterEnd(b)
 
-    b.Finish(mon)
+    if sizePrefix:
+        b.FinishSizePrefixed(mon)
+    else:
+        b.Finish(mon)
 
     return b.Bytes, b.Head()