- Create an all static TypedDataView class which uses implicit field offset

runtime/vm/object.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 3414 matching lines @@
   }
   void SetFieldAtOffset(intptr_t offset, const Object& value) const {
     StorePointer(FieldAddrAtOffset(offset), value.raw());
   }
   bool IsValidFieldOffset(int offset) const;
 
   // TODO(iposva): Determine if this gets in the way of Smi.
   HEAP_OBJECT_IMPLEMENTATION(Instance, Object);
   friend class Class;
   friend class Closure;
+  friend class TypedDataView;
 };
 
 
 // AbstractType is an abstract superclass.
 // Subclasses of AbstractType are Type and TypeParameter.
 class AbstractType : public Instance {
  public:
   virtual bool IsFinalized() const;
   virtual bool IsBeingFinalized() const;
   virtual bool IsMalformed() const;
@@ skipping 1638 matching lines @@
   static RawTypedData* New(intptr_t class_id,
                            intptr_t len,
                            Heap::Space space = Heap::kNew);
 
   static void Copy(const TypedData& dst,
                    intptr_t dst_offset_in_bytes,
                    const TypedData& src,
                    intptr_t src_offset_in_bytes,
                    intptr_t length_in_bytes);
 
+  static bool IsTypedData(const Instance& obj) {
+    ASSERT(!obj.IsNull());
+    intptr_t cid = obj.raw()->GetClassId();
+    return RawObject::IsTypedDataClassId(cid);
+  }
+
  protected:
   void SetLength(intptr_t value) const {
     raw_ptr()->length_ = Smi::New(value);
   }
 
  private:
   static const intptr_t element_size[];
 
   FINAL_HEAP_OBJECT_IMPLEMENTATION(TypedData, Instance);
   friend class Class;
   friend class ExternalTypedData;
+  friend class TypedDataView;
 };
 
 
 class ExternalTypedData : public Instance {
  public:
   intptr_t Length() const {
     ASSERT(!IsNull());
     return Smi::Value(raw_ptr()->length_);
   }
 
@@ skipping 64 matching lines @@
                                    uint8_t* data,
                                    intptr_t len,
                                    Heap::Space space = Heap::kNew);
 
   static void Copy(const ExternalTypedData& dst,
                    intptr_t dst_offset_in_bytes,
                    const ExternalTypedData& src,
                    intptr_t src_offset_in_bytes,
                    intptr_t length_in_bytes);
 
+  static bool IsExternalTypedData(const Instance& obj) {
+    ASSERT(!obj.IsNull());
+    intptr_t cid = obj.raw()->GetClassId();
+    return RawObject::IsExternalTypedDataClassId(cid);
+  }
+
  protected:
   void SetLength(intptr_t value) const {
     raw_ptr()->length_ = Smi::New(value);
   }
 
   void SetData(uint8_t* data) const {
     raw_ptr()->data_ = data;
   }
 
   void SetPeer(void* peer) const {
     raw_ptr()->peer_ = peer;
   }
 
  private:
   FINAL_HEAP_OBJECT_IMPLEMENTATION(ExternalTypedData, Instance);
   friend class Class;
 };
 
 
+class TypedDataView : public AllStatic {
+ public:
+  static intptr_t ElementSizeInBytes(const Instance& view_obj) {
+    ASSERT(!view_obj.IsNull());
+    intptr_t cid = view_obj.raw()->GetClassId();
+    return ElementSizeInBytes(cid);
+  }
+
+  static RawInstance* Data(const Instance& view_obj) {
+    ASSERT(!view_obj.IsNull());
+    return *reinterpret_cast<RawInstance**>(view_obj.raw_ptr() + kDataOffset);
+  }
+
+  static RawSmi* OffsetInBytes(const Instance& view_obj) {
+    ASSERT(!view_obj.IsNull());
+    return *reinterpret_cast<RawSmi**>(
+        view_obj.raw_ptr() + kOffsetInBytesOffset);
+  }
+
+  static RawSmi* Length(const Instance& view_obj) {
+    ASSERT(!view_obj.IsNull());
+    return *reinterpret_cast<RawSmi**>(view_obj.raw_ptr() + kLengthOffset);
+  }
+
+  static bool IsExternalTypedDataView(const Instance& view_obj) {
+    const Instance& data = Instance::Handle(Data(view_obj));
+    intptr_t cid = data.raw()->GetClassId();
+    ASSERT(RawObject::IsTypedDataClassId(cid) ||
+           RawObject::IsExternalTypedDataClassId(cid));
+    return RawObject::IsExternalTypedDataClassId(cid);
+  }
+
+  static intptr_t NumberOfFields() {
+    return (kLengthOffset - kTypeArguments);
+  }
+
+  static intptr_t data_offset() {
+    return kWordSize * kDataOffset;
+  }
+
+  static intptr_t offset_in_bytes_offset() {
+    return kWordSize * kOffsetInBytesOffset;
+  }
+
+  static intptr_t length_offset() {
+    return kWordSize * kLengthOffset;
+  }
+
+  static intptr_t ElementSizeInBytes(intptr_t class_id) {
+    ASSERT(RawObject::IsTypedDataViewClassId(class_id));
+    return (class_id == kByteDataViewCid) ?
+        TypedData::element_size[kTypedDataInt8ArrayCid] :
+        TypedData::element_size[class_id - kTypedDataInt8ArrayViewCid];
+  }
+
+ private:
+  enum {
+    kTypeArguments = 1,
+    kDataOffset = 2,
+    kOffsetInBytesOffset = 3,
+    kLengthOffset = 4,
+  };
+};
+
+
 // DartFunction represents the abstract Dart class 'Function'.
 class DartFunction : public Instance {
  private:
   FINAL_HEAP_OBJECT_IMPLEMENTATION(DartFunction, Instance);
   friend class Class;
   friend class Instance;
 };
 
 
 class Closure : public AllStatic {
@@ skipping 350 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_