Go speed testing

go/builder.go

@@ -31,11 +31,38 @@ func NewBuilder(initialSize int) *Builder {
 	return b
 }
 
+// Reset truncates the underlying Builder buffer, facilitating alloc-free
+// reuse of a Builder.
+func (b *Builder) Reset() {
+	if b.Bytes != nil {
+		b.Bytes = b.Bytes[:cap(b.Bytes)]
+	}
+
+	if b.vtables != nil {
+		b.vtables = b.vtables[:0]
+	}
+
+	if b.vtable != nil {
+		b.vtable = b.vtable[:0]
+	}
+
+	b.head = UOffsetT(len(b.Bytes))
+	b.minalign = 1
+}
+
 // StartObject initializes bookkeeping for writing a new object.
 func (b *Builder) StartObject(numfields int) {
 	b.notNested()
 	// use 32-bit offsets so that arithmetic doesn't overflow.
-	b.vtable = make([]UOffsetT, numfields)
+	if cap(b.vtable) < numfields || b.vtable == nil {
+		b.vtable = make([]UOffsetT, numfields)
+	} else {
+		b.vtable = b.vtable[:numfields]
+		for i := 0; i < len(b.vtable); i++ {
+			b.vtable[i] = 0
+		}
+	}
+
 	b.objectEnd = b.Offset()
 	b.minalign = 1
 }
@@ -137,7 +164,7 @@ func (b *Builder) WriteVtable() (n UOffsetT) {
 			SOffsetT(existingVtable)-SOffsetT(objectOffset))
 	}
 
-	b.vtable = nil
+	b.vtable = b.vtable[:0]
 	return objectOffset
 }
 
@@ -155,13 +182,20 @@ func (b *Builder) growByteBuffer() {
 	if (int64(len(b.Bytes)) & int64(0xC0000000)) != 0 {
 		panic("cannot grow buffer beyond 2 gigabytes")
 	}
-	newSize := len(b.Bytes) * 2
-	if newSize == 0 {
-		newSize = 1
+	newLen := len(b.Bytes) * 2
+	if newLen == 0 {
+		newLen = 1
+	}
+
+	if cap(b.Bytes) >= newLen {
+		b.Bytes = b.Bytes[:newLen]
+	} else {
+		extension := make([]byte, newLen-len(b.Bytes))
+		b.Bytes = append(b.Bytes, extension...)
 	}
-	bytes2 := make([]byte, newSize)
-	copy(bytes2[newSize-len(b.Bytes):], b.Bytes)
-	b.Bytes = bytes2
+
+	middle := newLen / 2
+	copy(b.Bytes[middle:], b.Bytes[:middle])
 }
 
 // Head gives the start of useful data in the underlying byte buffer.
@@ -247,16 +281,20 @@ func (b *Builder) EndVector(vectorNumElems int) UOffsetT {
 
 // CreateString writes a null-terminated string as a vector.
 func (b *Builder) CreateString(s string) UOffsetT {
+	return b.CreateByteString([]byte(s))
+}
+
+// CreateByteString writes a byte slice as a string (null-terminated).
+func (b *Builder) CreateByteString(s []byte) UOffsetT {
 	b.Prep(int(SizeUOffsetT), (len(s)+1)*SizeByte)
 	b.PlaceByte(0)
 
-	x := []byte(s)
-	l := UOffsetT(len(x))
+	l := UOffsetT(len(s))
 
 	b.head -= l
-	copy(b.Bytes[b.head:b.head+l], x)
+	copy(b.Bytes[b.head:b.head+l], s)
 
-	return b.EndVector(len(x))
+	return b.EndVector(len(s))
 }
 
 // CreateByteVector writes a ubyte vector
@@ -274,7 +312,7 @@ func (b *Builder) CreateByteVector(v []byte) UOffsetT {
 func (b *Builder) notNested() {
 	// Check that no other objects are being built while making this
 	// object. If not, panic:
-	if b.vtable != nil {
+	if len(b.vtable) > 0 {
 		panic("non-inline data write inside of object")
 	}
 }

go/table.go

@@ -26,10 +26,15 @@ func (t *Table) Indirect(off UOffsetT) UOffsetT {
 
 // String gets a string from data stored inside the flatbuffer.
 func (t *Table) String(off UOffsetT) string {
+	return string(t.ByteVector(off))
+}
+
+// ByteVector gets a byte slice from data stored inside the flatbuffer.
+func (t *Table) ByteVector(off UOffsetT) []byte {
 	off += GetUOffsetT(t.Bytes[off:])
 	start := off + UOffsetT(SizeUOffsetT)
 	length := GetUOffsetT(t.Bytes[off:])
-	return string(t.Bytes[start : start+length])
+	return t.Bytes[start : start+length]
 }
 
 // VectorLen retrieves the length of the vector whose offset is stored at

src/idl_gen_go.cpp

@@ -144,6 +144,19 @@ static void GetVectorLen(const StructDef &struct_def,
   code += "\treturn 0\n}\n\n";
 }
 
+// Get a [ubyte] vector as a byte slice.
+static void GetUByteSlice(const StructDef &struct_def,
+                          const FieldDef &field,
+                          std::string *code_ptr) {
+  std::string &code = *code_ptr;
+
+  GenReceiver(struct_def, code_ptr);
+  code += " " + MakeCamel(field.name) + "Bytes(";
+  code += ") []byte " + OffsetPrefix(field);
+  code += "\t\treturn rcv._tab.ByteVector(o + rcv._tab.Pos)\n\t}\n";
+  code += "\treturn nil\n}\n\n";
+}
+
 // Get the value of a struct's scalar.
 static void GetScalarFieldOfStruct(const StructDef &struct_def,
                                    const FieldDef &field,
@@ -225,7 +238,7 @@ static void GetStringField(const StructDef &struct_def,
   code += " " +  MakeCamel(field.name);
   code += "() " + TypeName(field) + " ";
   code += OffsetPrefix(field) + "\t\treturn " + GenGetter(field.value.type);
-  code += "(o + rcv._tab.Pos)\n\t}\n\treturn \"\"\n";
+  code += "(o + rcv._tab.Pos)\n\t}\n\treturn nil\n";
   code += "}\n\n";
 }
 
@@ -288,7 +301,7 @@ static void GetMemberOfVectorOfNonStruct(const StructDef &struct_def,
   code += NumToString(InlineSize(vectortype)) + "))\n";
   code += "\t}\n";
   if (vectortype.base_type == BASE_TYPE_STRING) {
-    code += "\treturn \"\"\n";
+    code += "\treturn nil\n";
   } else {
     code += "\treturn 0\n";
   }
@@ -480,6 +493,9 @@ static void GenStructAccessor(const StructDef &struct_def,
   }
   if (field.value.type.base_type == BASE_TYPE_VECTOR) {
     GetVectorLen(struct_def, field, code_ptr);
+    if (field.value.type.element == BASE_TYPE_UCHAR) {
+      GetUByteSlice(struct_def, field, code_ptr);
+    }
   }
 }
 
@@ -557,7 +573,7 @@ static void GenEnum(const EnumDef &enum_def, std::string *code_ptr) {
 // Returns the function name that is able to read a value of the given type.
 static std::string GenGetter(const Type &type) {
   switch (type.base_type) {
-    case BASE_TYPE_STRING: return "rcv._tab.String";
+    case BASE_TYPE_STRING: return "rcv._tab.ByteVector";
     case BASE_TYPE_UNION: return "rcv._tab.Union";
     case BASE_TYPE_VECTOR: return GenGetter(type.VectorType());
     default:
@@ -610,7 +626,7 @@ static std::string GenTypeBasic(const Type &type) {
 static std::string GenTypePointer(const Type &type) {
   switch (type.base_type) {
     case BASE_TYPE_STRING:
-      return "string";
+      return "[]byte";
     case BASE_TYPE_VECTOR:
       return GenTypeGet(type.VectorType());
     case BASE_TYPE_STRUCT:

src/idl_parser.cpp

@@ -947,6 +947,8 @@ void Parser::ParseDecl() {
   CheckClash("Type", BASE_TYPE_UNION);
   CheckClash("_length", BASE_TYPE_VECTOR);
   CheckClash("Length", BASE_TYPE_VECTOR);
+  CheckClash("_byte_vector", BASE_TYPE_STRING);
+  CheckClash("ByteVector", BASE_TYPE_STRING);
   Expect('}');
 }
 

tests/GoTest.sh

@@ -43,6 +43,8 @@ GOPATH=${go_path} go test flatbuffers_test \
                      --test.coverpkg=github.com/google/flatbuffers/go \
                      --cpp_data=${test_dir}/monsterdata_test.mon \
                      --out_data=${test_dir}/monsterdata_go_wire.mon \
+                     --test.bench=. \
+                     --test.benchtime=3s \
                      --fuzz=true \
                      --fuzz_fields=4 \
                      --fuzz_objects=10000

tests/MyGame/Example/Monster.go

@@ -50,12 +50,12 @@ func (rcv *Monster) Hp() int16 {
 	return 100
 }
 
-func (rcv *Monster) Name() string {
+func (rcv *Monster) Name() []byte {
 	o := flatbuffers.UOffsetT(rcv._tab.Offset(10))
 	if o != 0 {
-		return rcv._tab.String(o + rcv._tab.Pos)
+		return rcv._tab.ByteVector(o + rcv._tab.Pos)
 	}
-	return ""
+	return nil
 }
 
 func (rcv *Monster) Inventory(j int) byte {
@@ -75,6 +75,14 @@ func (rcv *Monster) InventoryLength() int {
 	return 0
 }
 
+func (rcv *Monster) InventoryBytes() []byte {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(14))
+	if o != 0 {
+		return rcv._tab.ByteVector(o + rcv._tab.Pos)
+	}
+	return nil
+}
+
 func (rcv *Monster) Color() int8 {
 	o := flatbuffers.UOffsetT(rcv._tab.Offset(16))
 	if o != 0 {
@@ -122,13 +130,13 @@ func (rcv *Monster) Test4Length() int {
 	return 0
 }
 
-func (rcv *Monster) Testarrayofstring(j int) string {
+func (rcv *Monster) Testarrayofstring(j int) []byte {
 	o := flatbuffers.UOffsetT(rcv._tab.Offset(24))
 	if o != 0 {
 		a := rcv._tab.Vector(o)
-		return rcv._tab.String(a + flatbuffers.UOffsetT(j * 4))
+		return rcv._tab.ByteVector(a + flatbuffers.UOffsetT(j * 4))
 	}
-	return ""
+	return nil
 }
 
 func (rcv *Monster) TestarrayofstringLength() int {
@@ -194,6 +202,14 @@ func (rcv *Monster) TestnestedflatbufferLength() int {
 	return 0
 }
 
+func (rcv *Monster) TestnestedflatbufferBytes() []byte {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(30))
+	if o != 0 {
+		return rcv._tab.ByteVector(o + rcv._tab.Pos)
+	}
+	return nil
+}
+
 func (rcv *Monster) Testempty(obj *Stat) *Stat {
 	o := flatbuffers.UOffsetT(rcv._tab.Offset(32))
 	if o != 0 {

tests/MyGame/Example/Stat.go

@@ -14,12 +14,12 @@ func (rcv *Stat) Init(buf []byte, i flatbuffers.UOffsetT) {
 	rcv._tab.Pos = i
 }
 
-func (rcv *Stat) Id() string {
+func (rcv *Stat) Id() []byte {
 	o := flatbuffers.UOffsetT(rcv._tab.Offset(4))
 	if o != 0 {
-		return rcv._tab.String(o + rcv._tab.Pos)
+		return rcv._tab.ByteVector(o + rcv._tab.Pos)
 	}
-	return ""
+	return nil
 }
 
 func (rcv *Stat) Val() int64 {