Merge pull request #248 from aeneid/master

Added Java and C# mutators

.gitignore

@@ -31,10 +31,15 @@ proguard-project.txt
 linklint_results
 Makefile
 flatc
+flatc.exe
 flathash
+flathash.exe
 flattests
+flattests.exe
 flatsamplebinary
+flatsamplebinary.exe
 flatsampletext
+flatsampletext.exe
 snapshot.sh
 tests/go_gen
 tests/monsterdata_java_wire.mon
@@ -50,3 +55,4 @@ java/.idea
 java/*.iml
 java/target
 **/*.pyc
+.idea
\ No newline at end of file

docs/source/JavaUsage.md

@@ -177,3 +177,48 @@ There currently is no support for parsing text (Schema's and JSON) directly
 from Java or C#, though you could use the C++ parser through native call
 interfaces available to each language. Please see the
 C++ documentation for more on text parsing.
+
+### Mutating FlatBuffers
+
+As you saw above, typically once you have created a FlatBuffer, it is
+read-only from that moment on. There are however cases where you have just
+received a FlatBuffer, and you'd like to modify something about it before
+sending it on to another recipient. With the above functionality, you'd have
+to generate an entirely new FlatBuffer, while tracking what you modify in your
+own data structures. This is inconvenient.
+
+For this reason FlatBuffers can also be mutated in-place. While this is great
+for making small fixes to an existing buffer, you generally want to create
+buffers from scratch whenever possible, since it is much more efficient and
+the API is much more general purpose.
+
+To get non-const accessors, invoke `flatc` with `--gen-mutable`.
+
+You now can:
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~{.java}
+    Monster monster = Monster.getRootAsMonster(bb);
+    monster.mutateHp(10);            // Set table field.
+    monster.pos().mutateZ(4);        // Set struct field.
+    monster.mutateInventory(0, 1);   // Set vector element.
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+We use the somewhat verbose term `mutate` instead of `set` to indicate that
+this is a special use case, not to be confused with the default way of
+constructing FlatBuffer data.
+
+After the above mutations, you can send on the FlatBuffer to a new recipient
+without any further work!
+
+Note that any `mutate` functions on tables return a boolean, which is false
+if the field we're trying to set isn't present in the buffer. Fields are not
+present if they weren't set, or even if they happen to be equal to the
+default value. For example, in the creation code above we set the `mana` field
+to `150`, which is the default value, so it was never stored in the buffer.
+Trying to call mutateMana() on such data will return false, and the value won't
+actually be modified!
+
+One way to solve this is to call `forceDefaults()` on a
+`FlatBufferBuilder` to force all fields you set to actually be written. This
+of course increases the size of the buffer somewhat, but this may be
+acceptable for a mutable buffer.

net/FlatBuffers/ByteBuffer.cs

@@ -35,10 +35,17 @@ namespace FlatBuffers
 
         public byte[] Data { get { return _buffer; } }
 
-        public ByteBuffer(byte[] buffer)
+        public ByteBuffer(byte[] buffer) : this(buffer, 0) { }
+
+        public ByteBuffer(byte[] buffer, int pos)
         {
             _buffer = buffer;
-            _pos = 0;
+            _pos = pos;
+        }
+
+        public int Position {
+            get { return _pos; }
+            set { _pos = value; }
         }
 
         public void Reset()
@@ -46,8 +53,6 @@ namespace FlatBuffers
             _pos = 0;
         }
 
-        public int Position { get { return _pos; } }
-
         // Pre-allocated helper arrays for convertion.
         private float[] floathelper = new[] { 0.0f };
         private int[] inthelper = new[] { 0 };
@@ -97,7 +102,6 @@ namespace FlatBuffers
                     _buffer[offset + count - 1 - i] = (byte)(data >> i * 8);
                 }
             }
-            _pos = offset;
         }
 
         protected ulong ReadLittleEndian(int offset, int count)
@@ -134,14 +138,18 @@ namespace FlatBuffers
         {
             AssertOffsetAndLength(offset, sizeof(sbyte));
             _buffer[offset] = (byte)value;
-            _pos = offset;
         }
 
         public void PutByte(int offset, byte value)
         {
             AssertOffsetAndLength(offset, sizeof(byte));
             _buffer[offset] = value;
-            _pos = offset;
+        }
+
+        // this method exists in order to conform with Java ByteBuffer standards
+        public void Put(int offset, byte value)
+        {
+            PutByte(offset, value);
         }
 
 #if UNSAFE_BYTEBUFFER

net/FlatBuffers/FlatBufferBuilder.cs

@@ -86,8 +86,7 @@ namespace FlatBuffers
 
             Buffer.BlockCopy(oldBuf, 0, newBuf, newBufSize - oldBufSize,
                              oldBufSize);
-
-            _bb = new ByteBuffer(newBuf);
+            _bb = new ByteBuffer(newBuf, newBufSize);
         }
 
         // Prepare to write an element of `size` after `additional_bytes`
@@ -370,6 +369,7 @@ namespace FlatBuffers
         {
             Prep(_minAlign, sizeof(int));
             AddOffset(rootTable);
+            _bb.Position = _space;
         }
 
         public ByteBuffer DataBuffer { get { return _bb; } }
@@ -398,7 +398,7 @@ namespace FlatBuffers
              {
                 AddByte((byte)fileIdentifier[i]);
              }
-             AddOffset(rootTable);
+             Finish(rootTable);
         }
 
 

src/idl_gen_general.cpp

@@ -363,6 +363,33 @@ static std::string DestinationValue(const LanguageParameters &lang,
   }
 }
 
+// Cast statements for mutator method parameters.
+// In Java, parameters representing unsigned numbers need to be cast down to their respective type.
+// For example, a long holding an unsigned int value would be cast down to int before being put onto the buffer.
+// In C#, one cast directly cast an Enum to its underlying type, which is essential before putting it onto the buffer.
+static std::string SourceCast(const LanguageParameters &lang,
+                              const Type &type) {
+  if (type.base_type == BASE_TYPE_VECTOR) {
+    return SourceCast(lang, type.VectorType());
+  } else {
+    switch (lang.language) {
+      case GeneratorOptions::kJava:
+        if (type.base_type == BASE_TYPE_UINT) return "(int)";
+        else if (type.base_type == BASE_TYPE_USHORT) return "(short)";
+        else if (type.base_type == BASE_TYPE_UCHAR) return "(byte)";
+        break;
+      case GeneratorOptions::kCSharp:
+        if (type.enum_def != nullptr && 
+            type.base_type != BASE_TYPE_UNION) 
+          return "(" + GenTypeGet(lang, type) + ")";
+        break;
+      default:
+        break;
+    }
+    return "";
+  }
+}
+
 static std::string GenDefaultValue(const LanguageParameters &lang, const Value &value, bool for_buffer) {
   if(lang.language == GeneratorOptions::kCSharp && !for_buffer) {
     switch(value.type.base_type) {
@@ -474,6 +501,22 @@ static std::string GenGetter(const LanguageParameters &lang,
   }
 }
 
+// Direct mutation is only allowed for scalar fields.
+// Hence a setter method will only be generated for such fields.
+static std::string GenSetter(const LanguageParameters &lang,
+                             const Type &type) {
+  if (IsScalar(type.base_type)) {
+    std::string setter = "bb." + FunctionStart(lang, 'P') + "ut";
+    if (GenTypeBasic(lang, type) != "byte" && 
+        type.base_type != BASE_TYPE_BOOL) {
+      setter += MakeCamel(GenTypeGet(lang, type));
+    }
+    return setter;
+  } else {
+    return "";
+  }
+}
+
 // Returns the method name for use with add/put calls.
 static std::string GenMethod(const LanguageParameters &lang, const Type &type) {
   return IsScalar(type.base_type)
@@ -539,7 +582,8 @@ static void GenStructBody(const LanguageParameters &lang,
 }
 
 static void GenStruct(const LanguageParameters &lang, const Parser &parser,
-                      StructDef &struct_def, std::string *code_ptr) {
+                      StructDef &struct_def, const GeneratorOptions &opts,
+                      std::string *code_ptr) {
   if (struct_def.generated) return;
   std::string &code = *code_ptr;
 
@@ -599,8 +643,10 @@ static void GenStruct(const LanguageParameters &lang, const Parser &parser,
     std::string type_name_dest = GenTypeNameDest(lang, field.value.type);
     std::string dest_mask = DestinationMask(lang, field.value.type, true);
     std::string dest_cast = DestinationCast(lang, field.value.type);
+    std::string src_cast = SourceCast(lang, field.value.type);
     std::string method_start = "  public " + type_name_dest + " " +
                                MakeCamel(field.name, lang.first_camel_upper);
+
     // Most field accessors need to retrieve and test the field offset first,
     // this is the prefix code for that:
     auto offset_prefix = " { int o = __offset(" +
@@ -744,6 +790,41 @@ static void GenStruct(const LanguageParameters &lang, const Parser &parser,
                           InlineSize(field.value.type.VectorType()));
       code += "); }\n";
     }
+
+    // generate mutators for scalar fields or vectors of scalars
+    if (opts.mutable_buffer) {
+      auto underlying_type = field.value.type.base_type == BASE_TYPE_VECTOR
+                    ? field.value.type.VectorType()
+                    : field.value.type;
+      // boolean parameters have to be explicitly converted to byte representation
+      auto setter_parameter = underlying_type.base_type == BASE_TYPE_BOOL ? "(byte)(" + field.name + " ? 1 : 0)" : field.name;
+      auto mutator_prefix = MakeCamel("mutate", lang.first_camel_upper);
+      //a vector mutator also needs the index of the vector element it should mutate
+      auto mutator_params = (field.value.type.base_type == BASE_TYPE_VECTOR ? "(int j, " : "(") +
+                            GenTypeNameDest(lang, underlying_type) + " " + 
+                            field.name + ") { ";
+      auto setter_index = field.value.type.base_type == BASE_TYPE_VECTOR
+                    ? "__vector(o) + j * " + NumToString(InlineSize(underlying_type))
+                    : (struct_def.fixed ? "bb_pos + " + NumToString(field.value.offset) : "o + bb_pos");
+      
+
+      if (IsScalar(field.value.type.base_type) || 
+          (field.value.type.base_type == BASE_TYPE_VECTOR &&
+          IsScalar(field.value.type.VectorType().base_type))) {
+        code += "  public ";
+        code += struct_def.fixed ? "void " : lang.bool_type;
+        code += mutator_prefix + MakeCamel(field.name, true);
+        code += mutator_params;
+        if (struct_def.fixed) {
+          code += GenSetter(lang, underlying_type) + "(" + setter_index + ", ";
+          code += src_cast + setter_parameter + "); }\n";
+        } else {
+          code += "int o = __offset(" + NumToString(field.value.offset) + ");";
+          code += " if (o != 0) { " + GenSetter(lang, underlying_type);
+          code += "(" + setter_index + ", " + src_cast + setter_parameter + "); return true; } else { return false; } }\n";
+        }
+      }
+    }
   }
   code += "\n";
   if (struct_def.fixed) {
@@ -980,7 +1061,7 @@ bool GenerateGeneral(const Parser &parser,
   for (auto it = parser.structs_.vec.begin();
        it != parser.structs_.vec.end(); ++it) {
     std::string declcode;
-    GenStruct(lang, parser, **it, &declcode);
+    GenStruct(lang, parser, **it, opts, &declcode);
     if (opts.one_file) {
       one_file_code += declcode;
     }

tests/FlatBuffers.Test/FlatBuffersExampleTests.cs

@@ -65,7 +65,6 @@ namespace FlatBuffers.Test
             fbb.AddOffset(test1.Value);
             var testArrayOfString = fbb.EndVector();
 
-
             Monster.StartMonster(fbb);
             Monster.AddPos(fbb, Vec3.CreateVec3(fbb, 1.0f, 2.0f, 3.0f, 3.0,
                                                      Color.Green, (short)5, (sbyte)6));
@@ -79,7 +78,8 @@ namespace FlatBuffers.Test
             Monster.AddTestbool(fbb, false);
             var mon = Monster.EndMonster(fbb);
 
-            fbb.Finish(mon.Value);
+            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))
@@ -90,6 +90,51 @@ namespace FlatBuffers.Test
 
             // Now assert the buffer
             TestBuffer(fbb.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);
+
+            // mana is optional and does not exist in the buffer so the mutation should fail
+            // the mana field should retain its default value
+            Assert.AreEqual(monster.MutateMana((short)10), false);
+            Assert.AreEqual(monster.Mana, (short)150);
+
+            // testType is an existing field and mutating it should succeed
+            Assert.AreEqual(monster.TestType, Any.Monster);
+            Assert.AreEqual(monster.MutateTestType(Any.NONE), true);
+            Assert.AreEqual(monster.TestType, Any.NONE);
+            Assert.AreEqual(monster.MutateTestType(Any.Monster), true);
+            Assert.AreEqual(monster.TestType, Any.Monster);
+
+            //mutate the inventory vector
+            Assert.AreEqual(monster.MutateInventory(0, 1), true);
+            Assert.AreEqual(monster.MutateInventory(1, 2), true);
+            Assert.AreEqual(monster.MutateInventory(2, 3), true);
+            Assert.AreEqual(monster.MutateInventory(3, 4), true);
+            Assert.AreEqual(monster.MutateInventory(4, 5), true);
+
+            for (int i = 0; i < monster.InventoryLength; i++)
+            {
+                Assert.AreEqual(monster.GetInventory(i), i + 1);
+            }
+
+            //reverse mutation
+            Assert.AreEqual(monster.MutateInventory(0, 0), true);
+            Assert.AreEqual(monster.MutateInventory(1, 1), true);
+            Assert.AreEqual(monster.MutateInventory(2, 2), true);
+            Assert.AreEqual(monster.MutateInventory(3, 3), true);
+            Assert.AreEqual(monster.MutateInventory(4, 4), true);
+
+            // get a struct field and edit one of its fields
+            Vec3 pos = monster.Pos;
+            Assert.AreEqual(pos.X, 1.0f);
+            pos.MutateX(55.0f);
+            Assert.AreEqual(pos.X, 55.0f);
+            pos.MutateX(1.0f);
+            Assert.AreEqual(pos.X, 1.0f);
+
+            TestBuffer(fbb.DataBuffer);
         }
 
         private void TestBuffer(ByteBuffer bb)

tests/FlatBuffers.Test/Program.cs

@@ -56,6 +56,7 @@ namespace FlatBuffers.Test
 
             }
 
+            Console.WriteLine("FlatBuffers test: completed successfully");
             return 0;
         }
     }

tests/JavaTest.java

@@ -81,6 +81,7 @@ class JavaTest {
         Monster.addTest4(fbb, test4);
         Monster.addTestarrayofstring(fbb, testArrayOfString);
         Monster.addTestbool(fbb, false);
+        Monster.addTesthashu32Fnv1(fbb, Integer.MAX_VALUE + 1L);
         int mon = Monster.endMonster(fbb);
 
         Monster.finishMonsterBuffer(fbb, mon);
@@ -101,15 +102,59 @@ class JavaTest {
         }
 
         // Test it:
-        TestBuffer(fbb.dataBuffer());
+        TestExtendedBuffer(fbb.dataBuffer());
 
         // Make sure it also works with read only ByteBuffers. This is slower,
         // since creating strings incurs an additional copy
         // (see Table.__string).
-        TestBuffer(fbb.dataBuffer().asReadOnlyBuffer());
+        TestExtendedBuffer(fbb.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());
+
+        // mana is optional and does not exist in the buffer so the mutation should fail
+        // the mana field should retain its default value
+        TestEq(monster.mutateMana((short)10), false);
+        TestEq(monster.mana(), (short)150);
+
+        // testType is an existing field and mutating it should succeed
+        TestEq(monster.testType(), (byte)Any.Monster);
+        TestEq(monster.mutateTestType(Any.NONE), true);
+        TestEq(monster.testType(), (byte)Any.NONE);
+        TestEq(monster.mutateTestType(Any.Monster), true);
+        TestEq(monster.testType(), (byte)Any.Monster);
+
+        //mutate the inventory vector
+        TestEq(monster.mutateInventory(0, 1), true);
+        TestEq(monster.mutateInventory(1, 2), true);
+        TestEq(monster.mutateInventory(2, 3), true);
+        TestEq(monster.mutateInventory(3, 4), true);
+        TestEq(monster.mutateInventory(4, 5), true);
+
+        for (int i = 0; i < monster.inventoryLength(); i++) {
+            TestEq(monster.inventory(i), i + 1);
+        }
+
+        //reverse mutation
+        TestEq(monster.mutateInventory(0, 0), true);
+        TestEq(monster.mutateInventory(1, 1), true);
+        TestEq(monster.mutateInventory(2, 2), true);
+        TestEq(monster.mutateInventory(3, 3), true);
+        TestEq(monster.mutateInventory(4, 4), true);
+
+        // get a struct field and edit one of its fields
+        Vec3 pos = monster.pos();
+        TestEq(pos.x(), 1.0f);
+        pos.mutateX(55.0f);
+        TestEq(pos.x(), 55.0f);
+        pos.mutateX(1.0f);
+        TestEq(pos.x(), 1.0f);
+
+        TestExtendedBuffer(fbb.dataBuffer().asReadOnlyBuffer());
+
         System.out.println("FlatBuffers test: completed successfully");
     }
 
@@ -171,6 +216,16 @@ class JavaTest {
         TestEq(monster.testbool(), false);
     }
 
+    // this method checks additional fields not present in the binary buffer read from file
+    // these new tests are performed on top of the regular tests
+    static void TestExtendedBuffer(ByteBuffer bb) {
+        TestBuffer(bb);
+
+        Monster monster = Monster.getRootAsMonster(bb);
+
+        TestEq(monster.testhashu32Fnv1(), Integer.MAX_VALUE + 1L);
+    }
+
     static <T> void TestEq(T a, T b) {
         if (!a.equals(b)) {
             System.out.println("" + a.getClass().getName() + " " + b.getClass().getName());

tests/MyGame/Example/Monster.cs

@@ -14,12 +14,17 @@ public sealed class Monster : Table {
   public Vec3 Pos { get { return GetPos(new Vec3()); } }
   public Vec3 GetPos(Vec3 obj) { int o = __offset(4); return o != 0 ? obj.__init(o + bb_pos, bb) : null; }
   public short Mana { get { int o = __offset(6); return o != 0 ? bb.GetShort(o + bb_pos) : (short)150; } }
+  public bool MutateMana(short mana) { int o = __offset(6); if (o != 0) { bb.PutShort(o + bb_pos, mana); return true; } else { return false; } }
   public short Hp { get { int o = __offset(8); return o != 0 ? bb.GetShort(o + bb_pos) : (short)100; } }
+  public bool MutateHp(short hp) { int o = __offset(8); if (o != 0) { bb.PutShort(o + bb_pos, hp); return true; } else { return false; } }
   public string Name { get { int o = __offset(10); return o != 0 ? __string(o + bb_pos) : null; } }
   public byte GetInventory(int j) { int o = __offset(14); return o != 0 ? bb.Get(__vector(o) + j * 1) : (byte)0; }
   public int InventoryLength { get { int o = __offset(14); return o != 0 ? __vector_len(o) : 0; } }
+  public bool MutateInventory(int j, byte inventory) { int o = __offset(14); if (o != 0) { bb.Put(__vector(o) + j * 1, inventory); return true; } else { return false; } }
   public Color Color { get { int o = __offset(16); return o != 0 ? (Color)bb.GetSbyte(o + bb_pos) : (Color)8; } }
+  public bool MutateColor(Color color) { int o = __offset(16); if (o != 0) { bb.PutSbyte(o + bb_pos, (sbyte)color); return true; } else { return false; } }
   public Any TestType { get { int o = __offset(18); return o != 0 ? (Any)bb.Get(o + bb_pos) : (Any)0; } }
+  public bool MutateTestType(Any test_type) { int o = __offset(18); if (o != 0) { bb.Put(o + bb_pos, (byte)test_type); return true; } else { return false; } }
   public TTable GetTest<TTable>(TTable obj) where TTable : Table { int o = __offset(20); return o != 0 ? __union(obj, o) : null; }
   public Test GetTest4(int j) { return GetTest4(new Test(), j); }
   public Test GetTest4(Test obj, int j) { int o = __offset(22); return o != 0 ? obj.__init(__vector(o) + j * 4, bb) : null; }
@@ -35,17 +40,27 @@ public sealed class Monster : Table {
   public Monster GetEnemy(Monster obj) { int o = __offset(28); return o != 0 ? obj.__init(__indirect(o + bb_pos), bb) : null; }
   public byte GetTestnestedflatbuffer(int j) { int o = __offset(30); return o != 0 ? bb.Get(__vector(o) + j * 1) : (byte)0; }
   public int TestnestedflatbufferLength { get { int o = __offset(30); return o != 0 ? __vector_len(o) : 0; } }
+  public bool MutateTestnestedflatbuffer(int j, byte testnestedflatbuffer) { int o = __offset(30); if (o != 0) { bb.Put(__vector(o) + j * 1, testnestedflatbuffer); return true; } else { return false; } }
   public Stat Testempty { get { return GetTestempty(new Stat()); } }
   public Stat GetTestempty(Stat obj) { int o = __offset(32); return o != 0 ? obj.__init(__indirect(o + bb_pos), bb) : null; }
   public bool Testbool { get { int o = __offset(34); return o != 0 ? 0!=bb.Get(o + bb_pos) : (bool)false; } }
+  public bool MutateTestbool(bool testbool) { int o = __offset(34); if (o != 0) { bb.Put(o + bb_pos, (byte)(testbool ? 1 : 0)); return true; } else { return false; } }
   public int Testhashs32Fnv1 { get { int o = __offset(36); return o != 0 ? bb.GetInt(o + bb_pos) : (int)0; } }
+  public bool MutateTesthashs32Fnv1(int testhashs32_fnv1) { int o = __offset(36); if (o != 0) { bb.PutInt(o + bb_pos, testhashs32_fnv1); return true; } else { return false; } }
   public uint Testhashu32Fnv1 { get { int o = __offset(38); return o != 0 ? bb.GetUint(o + bb_pos) : (uint)0; } }
+  public bool MutateTesthashu32Fnv1(uint testhashu32_fnv1) { int o = __offset(38); if (o != 0) { bb.PutUint(o + bb_pos, testhashu32_fnv1); return true; } else { return false; } }
   public long Testhashs64Fnv1 { get { int o = __offset(40); return o != 0 ? bb.GetLong(o + bb_pos) : (long)0; } }
+  public bool MutateTesthashs64Fnv1(long testhashs64_fnv1) { int o = __offset(40); if (o != 0) { bb.PutLong(o + bb_pos, testhashs64_fnv1); return true; } else { return false; } }
   public ulong Testhashu64Fnv1 { get { int o = __offset(42); return o != 0 ? bb.GetUlong(o + bb_pos) : (ulong)0; } }
+  public bool MutateTesthashu64Fnv1(ulong testhashu64_fnv1) { int o = __offset(42); if (o != 0) { bb.PutUlong(o + bb_pos, testhashu64_fnv1); return true; } else { return false; } }
   public int Testhashs32Fnv1a { get { int o = __offset(44); return o != 0 ? bb.GetInt(o + bb_pos) : (int)0; } }
+  public bool MutateTesthashs32Fnv1a(int testhashs32_fnv1a) { int o = __offset(44); if (o != 0) { bb.PutInt(o + bb_pos, testhashs32_fnv1a); return true; } else { return false; } }
   public uint Testhashu32Fnv1a { get { int o = __offset(46); return o != 0 ? bb.GetUint(o + bb_pos) : (uint)0; } }
+  public bool MutateTesthashu32Fnv1a(uint testhashu32_fnv1a) { int o = __offset(46); if (o != 0) { bb.PutUint(o + bb_pos, testhashu32_fnv1a); return true; } else { return false; } }
   public long Testhashs64Fnv1a { get { int o = __offset(48); return o != 0 ? bb.GetLong(o + bb_pos) : (long)0; } }
+  public bool MutateTesthashs64Fnv1a(long testhashs64_fnv1a) { int o = __offset(48); if (o != 0) { bb.PutLong(o + bb_pos, testhashs64_fnv1a); return true; } else { return false; } }
   public ulong Testhashu64Fnv1a { get { int o = __offset(50); return o != 0 ? bb.GetUlong(o + bb_pos) : (ulong)0; } }
+  public bool MutateTesthashu64Fnv1a(ulong testhashu64_fnv1a) { int o = __offset(50); if (o != 0) { bb.PutUlong(o + bb_pos, testhashu64_fnv1a); return true; } else { return false; } }
 
   public static void StartMonster(FlatBufferBuilder builder) { builder.StartObject(24); }
   public static void AddPos(FlatBufferBuilder builder, Offset<Vec3> posOffset) { builder.AddStruct(0, posOffset.Value, 0); }

tests/MyGame/Example/Monster.java

@@ -16,14 +16,19 @@ public final class Monster extends Table {
   public Vec3 pos() { return pos(new Vec3()); }
   public Vec3 pos(Vec3 obj) { int o = __offset(4); return o != 0 ? obj.__init(o + bb_pos, bb) : null; }
   public short mana() { int o = __offset(6); return o != 0 ? bb.getShort(o + bb_pos) : 150; }
+  public boolean mutateMana(short mana) { int o = __offset(6); if (o != 0) { bb.putShort(o + bb_pos, mana); return true; } else { return false; } }
   public short hp() { int o = __offset(8); return o != 0 ? bb.getShort(o + bb_pos) : 100; }
+  public boolean mutateHp(short hp) { int o = __offset(8); if (o != 0) { bb.putShort(o + bb_pos, hp); return true; } else { return false; } }
   public String name() { int o = __offset(10); return o != 0 ? __string(o + bb_pos) : null; }
   public ByteBuffer nameAsByteBuffer() { return __vector_as_bytebuffer(10, 1); }
   public int inventory(int j) { int o = __offset(14); return o != 0 ? bb.get(__vector(o) + j * 1) & 0xFF : 0; }
   public int inventoryLength() { int o = __offset(14); return o != 0 ? __vector_len(o) : 0; }
   public ByteBuffer inventoryAsByteBuffer() { return __vector_as_bytebuffer(14, 1); }
+  public boolean mutateInventory(int j, int inventory) { int o = __offset(14); if (o != 0) { bb.put(__vector(o) + j * 1, (byte)inventory); return true; } else { return false; } }
   public byte color() { int o = __offset(16); return o != 0 ? bb.get(o + bb_pos) : 8; }
+  public boolean mutateColor(byte color) { int o = __offset(16); if (o != 0) { bb.put(o + bb_pos, color); return true; } else { return false; } }
   public byte testType() { int o = __offset(18); return o != 0 ? bb.get(o + bb_pos) : 0; }
+  public boolean mutateTestType(byte test_type) { int o = __offset(18); if (o != 0) { bb.put(o + bb_pos, test_type); return true; } else { return false; } }
   public Table test(Table obj) { int o = __offset(20); return o != 0 ? __union(obj, o) : null; }
   public Test test4(int j) { return test4(new Test(), j); }
   public Test test4(Test obj, int j) { int o = __offset(22); return o != 0 ? obj.__init(__vector(o) + j * 4, bb) : null; }
@@ -42,17 +47,27 @@ public final class Monster extends Table {
   public int testnestedflatbuffer(int j) { int o = __offset(30); return o != 0 ? bb.get(__vector(o) + j * 1) & 0xFF : 0; }
   public int testnestedflatbufferLength() { int o = __offset(30); return o != 0 ? __vector_len(o) : 0; }
   public ByteBuffer testnestedflatbufferAsByteBuffer() { return __vector_as_bytebuffer(30, 1); }
+  public boolean mutateTestnestedflatbuffer(int j, int testnestedflatbuffer) { int o = __offset(30); if (o != 0) { bb.put(__vector(o) + j * 1, (byte)testnestedflatbuffer); return true; } else { return false; } }
   public Stat testempty() { return testempty(new Stat()); }
   public Stat testempty(Stat obj) { int o = __offset(32); return o != 0 ? obj.__init(__indirect(o + bb_pos), bb) : null; }
   public boolean testbool() { int o = __offset(34); return o != 0 ? 0!=bb.get(o + bb_pos) : false; }
+  public boolean mutateTestbool(boolean testbool) { int o = __offset(34); if (o != 0) { bb.put(o + bb_pos, (byte)(testbool ? 1 : 0)); return true; } else { return false; } }
   public int testhashs32Fnv1() { int o = __offset(36); return o != 0 ? bb.getInt(o + bb_pos) : 0; }
+  public boolean mutateTesthashs32Fnv1(int testhashs32_fnv1) { int o = __offset(36); if (o != 0) { bb.putInt(o + bb_pos, testhashs32_fnv1); return true; } else { return false; } }
   public long testhashu32Fnv1() { int o = __offset(38); return o != 0 ? (long)bb.getInt(o + bb_pos) & 0xFFFFFFFFL : 0; }
+  public boolean mutateTesthashu32Fnv1(long testhashu32_fnv1) { int o = __offset(38); if (o != 0) { bb.putInt(o + bb_pos, (int)testhashu32_fnv1); return true; } else { return false; } }
   public long testhashs64Fnv1() { int o = __offset(40); return o != 0 ? bb.getLong(o + bb_pos) : 0; }
+  public boolean mutateTesthashs64Fnv1(long testhashs64_fnv1) { int o = __offset(40); if (o != 0) { bb.putLong(o + bb_pos, testhashs64_fnv1); return true; } else { return false; } }
   public long testhashu64Fnv1() { int o = __offset(42); return o != 0 ? bb.getLong(o + bb_pos) : 0; }
+  public boolean mutateTesthashu64Fnv1(long testhashu64_fnv1) { int o = __offset(42); if (o != 0) { bb.putLong(o + bb_pos, testhashu64_fnv1); return true; } else { return false; } }
   public int testhashs32Fnv1a() { int o = __offset(44); return o != 0 ? bb.getInt(o + bb_pos) : 0; }
+  public boolean mutateTesthashs32Fnv1a(int testhashs32_fnv1a) { int o = __offset(44); if (o != 0) { bb.putInt(o + bb_pos, testhashs32_fnv1a); return true; } else { return false; } }
   public long testhashu32Fnv1a() { int o = __offset(46); return o != 0 ? (long)bb.getInt(o + bb_pos) & 0xFFFFFFFFL : 0; }
+  public boolean mutateTesthashu32Fnv1a(long testhashu32_fnv1a) { int o = __offset(46); if (o != 0) { bb.putInt(o + bb_pos, (int)testhashu32_fnv1a); return true; } else { return false; } }
   public long testhashs64Fnv1a() { int o = __offset(48); return o != 0 ? bb.getLong(o + bb_pos) : 0; }
+  public boolean mutateTesthashs64Fnv1a(long testhashs64_fnv1a) { int o = __offset(48); if (o != 0) { bb.putLong(o + bb_pos, testhashs64_fnv1a); return true; } else { return false; } }
   public long testhashu64Fnv1a() { int o = __offset(50); return o != 0 ? bb.getLong(o + bb_pos) : 0; }
+  public boolean mutateTesthashu64Fnv1a(long testhashu64_fnv1a) { int o = __offset(50); if (o != 0) { bb.putLong(o + bb_pos, testhashu64_fnv1a); return true; } else { return false; } }
 
   public static void startMonster(FlatBufferBuilder builder) { builder.startObject(24); }
   public static void addPos(FlatBufferBuilder builder, int posOffset) { builder.addStruct(0, posOffset, 0); }

tests/MyGame/Example/Stat.cs

@@ -12,7 +12,9 @@ public sealed class Stat : Table {
 
   public string Id { get { int o = __offset(4); return o != 0 ? __string(o + bb_pos) : null; } }
   public long Val { get { int o = __offset(6); return o != 0 ? bb.GetLong(o + bb_pos) : (long)0; } }
+  public bool MutateVal(long val) { int o = __offset(6); if (o != 0) { bb.PutLong(o + bb_pos, val); return true; } else { return false; } }
   public ushort Count { get { int o = __offset(8); return o != 0 ? bb.GetUshort(o + bb_pos) : (ushort)0; } }
+  public bool MutateCount(ushort count) { int o = __offset(8); if (o != 0) { bb.PutUshort(o + bb_pos, count); return true; } else { return false; } }
 
   public static Offset<Stat> CreateStat(FlatBufferBuilder builder,
       StringOffset id = default(StringOffset),

tests/MyGame/Example/Stat.java

@@ -15,7 +15,9 @@ public final class Stat extends Table {
   public String id() { int o = __offset(4); return o != 0 ? __string(o + bb_pos) : null; }
   public ByteBuffer idAsByteBuffer() { return __vector_as_bytebuffer(4, 1); }
   public long val() { int o = __offset(6); return o != 0 ? bb.getLong(o + bb_pos) : 0; }
+  public boolean mutateVal(long val) { int o = __offset(6); if (o != 0) { bb.putLong(o + bb_pos, val); return true; } else { return false; } }
   public int count() { int o = __offset(8); return o != 0 ? bb.getShort(o + bb_pos) & 0xFFFF : 0; }
+  public boolean mutateCount(int count) { int o = __offset(8); if (o != 0) { bb.putShort(o + bb_pos, (short)count); return true; } else { return false; } }
 
   public static int createStat(FlatBufferBuilder builder,
       int id,

tests/MyGame/Example/Test.cs

@@ -9,7 +9,9 @@ public sealed class Test : Struct {
   public Test __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; return this; }
 
   public short A { get { return bb.GetShort(bb_pos + 0); } }
+  public void MutateA(short a) { bb.PutShort(bb_pos + 0, a); }
   public sbyte B { get { return bb.GetSbyte(bb_pos + 2); } }
+  public void MutateB(sbyte b) { bb.PutSbyte(bb_pos + 2, b); }
 
   public static Offset<Test> CreateTest(FlatBufferBuilder builder, short A, sbyte B) {
     builder.Prep(2, 4);

tests/MyGame/Example/Test.java

@@ -11,7 +11,9 @@ public final class Test extends Struct {
   public Test __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; return this; }
 
   public short a() { return bb.getShort(bb_pos + 0); }
+  public void mutateA(short a) { bb.putShort(bb_pos + 0, a); }
   public byte b() { return bb.get(bb_pos + 2); }
+  public void mutateB(byte b) { bb.put(bb_pos + 2, b); }
 
   public static int createTest(FlatBufferBuilder builder, short a, byte b) {
     builder.prep(2, 4);

tests/MyGame/Example/Vec3.cs

@@ -9,10 +9,15 @@ public sealed class Vec3 : Struct {
   public Vec3 __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; return this; }
 
   public float X { get { return bb.GetFloat(bb_pos + 0); } }
+  public void MutateX(float x) { bb.PutFloat(bb_pos + 0, x); }
   public float Y { get { return bb.GetFloat(bb_pos + 4); } }
+  public void MutateY(float y) { bb.PutFloat(bb_pos + 4, y); }
   public float Z { get { return bb.GetFloat(bb_pos + 8); } }
+  public void MutateZ(float z) { bb.PutFloat(bb_pos + 8, z); }
   public double Test1 { get { return bb.GetDouble(bb_pos + 16); } }
+  public void MutateTest1(double test1) { bb.PutDouble(bb_pos + 16, test1); }
   public Color Test2 { get { return (Color)bb.GetSbyte(bb_pos + 24); } }
+  public void MutateTest2(Color test2) { bb.PutSbyte(bb_pos + 24, (sbyte)test2); }
   public Test Test3 { get { return GetTest3(new Test()); } }
   public Test GetTest3(Test obj) { return obj.__init(bb_pos + 26, bb); }
 

tests/MyGame/Example/Vec3.java

@@ -11,10 +11,15 @@ public final class Vec3 extends Struct {
   public Vec3 __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; return this; }
 
   public float x() { return bb.getFloat(bb_pos + 0); }
+  public void mutateX(float x) { bb.putFloat(bb_pos + 0, x); }
   public float y() { return bb.getFloat(bb_pos + 4); }
+  public void mutateY(float y) { bb.putFloat(bb_pos + 4, y); }
   public float z() { return bb.getFloat(bb_pos + 8); }
+  public void mutateZ(float z) { bb.putFloat(bb_pos + 8, z); }
   public double test1() { return bb.getDouble(bb_pos + 16); }
+  public void mutateTest1(double test1) { bb.putDouble(bb_pos + 16, test1); }
   public byte test2() { return bb.get(bb_pos + 24); }
+  public void mutateTest2(byte test2) { bb.put(bb_pos + 24, test2); }
   public Test test3() { return test3(new Test()); }
   public Test test3(Test obj) { return obj.__init(bb_pos + 26, bb); }