Add an external array type to support typed arrays.

runtime/vm/object_test.cc

Index: runtime/vm/object_test.cc
diff --git a/runtime/vm/object_test.cc b/runtime/vm/object_test.cc
index 8e2778d6371b2d9fd07a25edd40a449db84b6433..763bbacd242849c32a8e1e8ee82ca843ce551068 100644
--- a/runtime/vm/object_test.cc
+++ b/runtime/vm/object_test.cc
@@ -1593,6 +1593,40 @@ TEST_CASE(Array) {
 }
 
 
+TEST_CASE(ExternalArray) {
+  uint8_t data[] = { 253, 254, 255, 0, 1, 2, 3 };
+  intptr_t data_length = ARRAY_SIZE(data);
+
+  const ExternalArray& array1 =
+      ExternalArray::Handle(ExternalArray::New(data, data_length));
+  EXPECT(!array1.IsNull());
+  EXPECT_EQ(data_length, array1.Length());
+  EXPECT_EQ(-3, array1.Int8At(0));
+  EXPECT_EQ(253, array1.Uint8At(0));
+  EXPECT_EQ(-2, array1.Int8At(1));
+  EXPECT_EQ(254, array1.Uint8At(1));
+  EXPECT_EQ(-1, array1.Int8At(2));
+  EXPECT_EQ(255, array1.Uint8At(2));
+  EXPECT_EQ(0, array1.Int8At(3));
+  EXPECT_EQ(0, array1.Uint8At(3));
+  EXPECT_EQ(1, array1.Int8At(4));
+  EXPECT_EQ(1, array1.Uint8At(4));
+  EXPECT_EQ(2, array1.Int8At(5));
+  EXPECT_EQ(2, array1.Uint8At(5));

[siva, 2011/11/02 17:05:31]

We probably need unit tests for get/set of other types too, maybe have a
templatized version or something to avoid having to retype this again.

[cshapiro, 2011/11/04 18:16:21]

It is not entirely clear how to do this.  I have simplified the access routine
so the getter and setter is now templatized although I think you are suggesting
a more meaningful change.

+
+  const ExternalArray& array2 =
+      ExternalArray::Handle(ExternalArray::New(data, data_length));
+  EXPECT(!array1.IsNull());
+  EXPECT_EQ(data_length, array2.Length());
+  EXPECT(array1.Equals(array2));
+  EXPECT(array2.Equals(array1));
+  array1.SetUint8At(0, 123);
+  array2.SetInt8At(2, -123);
+  EXPECT(array1.Equals(array2));
+  EXPECT(array2.Equals(array1));

[siva, 2011/11/02 17:05:31]

We should set some different values and check that array1.Equals(array2) returns
false in that case.

[cshapiro, 2011/11/04 18:16:21]

Absolutely.  Done in the more recent patch set.

+}
+
+
 TEST_CASE(Script) {
   const char* url_chars = "builtin:test-case";
   const char* source_chars = "This will not compile.";