Use corerct conversions for DataView accessors.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index fbad080346e46bb8e1db5556871cb307d85872c2..116fe019bc0f41b9f78d2666e1c82148ff296bdb 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -1216,6 +1216,59 @@ DATA_VIEW_GETTER(Float64, double, NumberFromDouble)
 
 #undef DATA_VIEW_GETTER
 
+
+template <typename T>
+static T DataViewValueConverter(double value);

[titzer, 2013/07/12 16:37:02]

Can we name this function verb-ly, such as "ConvertDoubleToDataView"?

[Dmitry Lomov (no reviews), 2013/07/12 18:22:45]

Done.
ConvertValueToDataView is not a good name - we convert value to T, not to
DataView.
I called it DataViewConvertValue (similar to DataViewGetValue and
DataViewSetValue)
On 2013/07/12 16:37:02, titzer wrote:

+
+
+template <>
+int8_t DataViewValueConverter<int8_t>(double value) {
+  return static_cast<int8_t>(DoubleToInt32(value));
+}
+
+
+template <>
+int16_t DataViewValueConverter<int16_t>(double value) {
+  return static_cast<int16_t>(DoubleToInt32(value));
+}
+
+
+template <>
+int32_t DataViewValueConverter<int32_t>(double value) {
+  return DoubleToInt32(value);
+}
+
+
+template <>
+uint8_t DataViewValueConverter<uint8_t>(double value) {
+  return static_cast<uint8_t>(DoubleToUint32(value));
+}
+
+
+template <>
+uint16_t DataViewValueConverter<uint16_t>(double value) {
+  return static_cast<uint16_t>(DoubleToUint32(value));
+}
+
+
+template <>
+uint32_t DataViewValueConverter<uint32_t>(double value) {
+  return DoubleToUint32(value);
+}
+
+
+template <>
+float DataViewValueConverter<float>(double value) {
+  return static_cast<float>(value);
+}
+
+
+template <>
+double DataViewValueConverter<double>(double value) {
+  return value;
+}
+
+
 #define DATA_VIEW_SETTER(TypeName, Type)                                      \
   RUNTIME_FUNCTION(MaybeObject*, Runtime_DataViewSet##TypeName) {             \
     HandleScope scope(isolate);                                               \
@@ -1224,7 +1277,7 @@ DATA_VIEW_GETTER(Float64, double, NumberFromDouble)
     CONVERT_ARG_HANDLE_CHECKED(Object, offset, 1);                            \
     CONVERT_ARG_HANDLE_CHECKED(Object, value, 2);                             \
     CONVERT_BOOLEAN_ARG_CHECKED(is_little_endian, 3);                         \
-    Type v = static_cast<Type>(value->Number());                              \
+    Type v = DataViewValueConverter<Type>(value->Number());                   \
     if (DataViewSetValue(                                                     \
           isolate, holder, offset, is_little_endian, v)) {                    \
       return isolate->heap()->undefined_value();                              \