- implement IsNegative for class Double

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 4777 matching lines @@
   static RawMixinAppType* New();
 
   FINAL_HEAP_OBJECT_IMPLEMENTATION(MixinAppType, AbstractType);
   friend class Class;
 };
 
 
 class Number : public Instance {
  public:
   // TODO(iposva): Fill in a useful Number interface.
-  virtual bool IsZero() const {
-    // Number is an abstract class.
-    UNREACHABLE();
-    return false;
-  }
   virtual bool IsNegative() const {
     // Number is an abstract class.
     UNREACHABLE();
     return false;
   }
+
+ private:
   OBJECT_IMPLEMENTATION(Number, Instance);
   friend class Class;
 };
 
 
 class Integer : public Number {
  public:
   static RawInteger* New(const String& str, Heap::Space space = Heap::kNew);
   static RawInteger* NewFromUint64(
       uint64_t value, Heap::Space space = Heap::kNew);
 
   // Returns a canonical Integer object allocated in the old gen space.
   static RawInteger* NewCanonical(const String& str);
 
   // Do not throw JavascriptIntegerOverflow if 'silent' is true.
   static RawInteger* New(int64_t value,
                          Heap::Space space = Heap::kNew,
                          const bool silent = false);
 
+  // Integer is an abstract class.
+  virtual bool IsZero() const {
+    UNREACHABLE();
+    return false;
+  }
   virtual double AsDoubleValue() const;
   virtual int64_t AsInt64Value() const;
   virtual uint32_t AsTruncatedUint32Value() const;
 
   // Returns 0, -1 or 1.
   virtual int CompareWith(const Integer& other) const;
 
   // Return the most compact presentation of an integer.
   RawInteger* AsValidInteger() const;
 
@@ skipping 236 matching lines @@
 // Class Double represents class Double in corelib_impl, which implements
 // abstract class double in corelib.
 class Double : public Number {
  public:
   double value() const {
     return raw_ptr()->value_;
   }
 
   bool EqualsToDouble(double value) const;
   virtual bool Equals(const Instance& other) const;
+  virtual bool IsNegative() const {
+    double dval = value();
+    return (signbit(dval) && !isnan(dval));
+  }
 
   static RawDouble* New(double d, Heap::Space space = Heap::kNew);
 
   static RawDouble* New(const String& str, Heap::Space space = Heap::kNew);
 
   // Returns a canonical double object allocated in the old gen space.
   static RawDouble* NewCanonical(double d);
 
   // Returns a canonical double object (allocated in the old gen space) or
   // Double::null() if str points to a string that does not convert to a
@@ skipping 1883 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_