v8 typed arrays: add DataView type

test/cctest/test-api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2592 matching lines @@
   CHECK_EQ(100, result->Int32Value());
   CHECK_EQ(0xBB, my_data[0]);
   CHECK_EQ(0xCC, my_data[1]);
   my_data[0] = 0xCC;
   my_data[1] = 0x11;
   result = CompileRun("u8_b[0] + u8_b[1]");
   CHECK_EQ(0xDD, result->Int32Value());
 }
 
 
+THREADED_TEST(DataView) {
+  i::FLAG_harmony_data_view = true;
+  i::FLAG_harmony_typed_arrays = true;
+
+  LocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+  v8::HandleScope handle_scope(isolate);
+
+  char data[1024];
+  const int kByteOffset = 256;
+  const int kByteLength = sizeof(data) - kByteOffset;
+
+  Local<v8::ArrayBuffer> array_buffer =
+      v8::ArrayBuffer::New(data, sizeof(data));
+  Local<v8::DataView> data_view =
+      v8::DataView::New(array_buffer, kByteOffset, kByteLength);
+  HEAP->CollectAllGarbage(i::Heap::kNoGCFlags);
+
+  CHECK_EQ(kByteOffset, data_view->ByteOffset());
+  CHECK_EQ(kByteLength, data_view->ByteLength());
+  CHECK_EQ(static_cast<void*>(data + kByteOffset), data_view->Data());
+
+  data_view->SetUint32(0, 0x12345678, false);             // Big-endian
+  CHECK_EQ(0x12, data_view->GetUint8(0));
+  CHECK_EQ(0x34, data_view->GetUint8(1));
+  CHECK_EQ(0x56, data_view->GetUint8(2));
+  CHECK_EQ(0x78, data_view->GetUint8(3));
+  CHECK_EQ(0x1234, data_view->GetUint16(0));              // Big-endian
+  CHECK_EQ(0x5678, data_view->GetUint16(2));              // Big-endian
+  CHECK_EQ(0x1234, data_view->GetUint16(0, false));       // Big-endian
+  CHECK_EQ(0x3412, data_view->GetUint16(0, true));        // Little-endian
+  CHECK_EQ(0x5678, data_view->GetUint16(2, false));       // Big-endian
+  CHECK_EQ(0x7856, data_view->GetUint16(2, true));        // Little-endian
+  CHECK_EQ(0x12345678, data_view->GetUint32(0));          // Big-endian
+  CHECK_EQ(0x12345678, data_view->GetUint32(0, false));   // Big-endian
+  CHECK_EQ(0x78563412, data_view->GetUint32(0, true));    // Little-endian
+
+  data_view->SetUint32(0, 0x12345678, true);              // Little-endian
+  CHECK_EQ(0x78, data_view->GetUint8(0));
+  CHECK_EQ(0x56, data_view->GetUint8(1));
+  CHECK_EQ(0x34, data_view->GetUint8(2));
+  CHECK_EQ(0x12, data_view->GetUint8(3));
+  CHECK_EQ(0x7856, data_view->GetUint16(0));              // Big-endian
+  CHECK_EQ(0x3412, data_view->GetUint16(2));              // Big-endian
+  CHECK_EQ(0x7856, data_view->GetUint16(0, false));       // Big-endian
+  CHECK_EQ(0x5678, data_view->GetUint16(0, true));        // Little-endian
+  CHECK_EQ(0x3412, data_view->GetUint16(2, false));       // Big-endian
+  CHECK_EQ(0x1234, data_view->GetUint16(2, true));        // Little-endian
+  CHECK_EQ(0x78563412, data_view->GetUint32(0));          // Big-endian.
+  CHECK_EQ(0x78563412, data_view->GetUint32(0, false));   // Big-endian.
+  CHECK_EQ(0x12345678, data_view->GetUint32(0, true));    // Little-endian.
+
+  data_view->SetFloat32(0, 123.456f);
+  data_view->SetFloat64(4, 123.456);
+  CHECK_EQ(123.456f, data_view->GetFloat32(0));
+  CHECK_EQ(123.456, data_view->GetFloat64(4));

[bnoordhuis, 2013/05/23 22:59:04]

But if you decide to keep the API functions, there should probably be some
discussion on how to handle NaNs and other edge cases.  The DataView spec leaves
that remarkably wide open, the only requirement is that it's valid IEEE 754:

" When the not-a-number (NaN) value is stored into a Float32Array or
Float64Array, or into a DataView using the setFloat32 or setFloat64 methods, the
bit pattern written into the underlying ArrayBuffer is not specified, but shall
be one of the IEEE 754 bit patterns that represent NaN [IEEE-754].

When a bit pattern representing an IEEE 754 NaN is loaded from a Float32Array or
Float64Array, or from a DataView using the getFloat32 or getFloat64 methods, the
language binding (for example, ECMAScript) may use an alternative bit pattern to
represent the NaN value."

+}
+
+
 THREADED_TEST(HiddenProperties) {
   LocalContext env;
   v8::HandleScope scope(env->GetIsolate());
 
   v8::Local<v8::Object> obj = v8::Object::New();
   v8::Local<v8::String> key = v8_str("api-test::hidden-key");
   v8::Local<v8::String> empty = v8_str("");
   v8::Local<v8::String> prop_name = v8_str("prop_name");
 
   HEAP->CollectAllGarbage(i::Heap::kNoGCFlags);
@@ skipping 16678 matching lines @@
   i::Semaphore* sem_;
   volatile int sem_value_;
 };
 
 
 THREADED_TEST(SemaphoreInterruption) {
   ThreadInterruptTest().RunTest();
 }
 
 #endif  // WIN32