Add an external array type to support typed arrays.

runtime/lib/byte_buffer.cc

+// Copyright (c) 2011, 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.
+
+#include "vm/bootstrap_natives.h"
+
+#include "vm/assembler.h"
+#include "vm/assert.h"
+#include "vm/bigint_operations.h"
+#include "vm/exceptions.h"
+#include "vm/native_entry.h"
+#include "vm/object.h"
+
+namespace dart {
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_allocate, 2) {
+  const Instance& length_instance = Instance::CheckedHandle(arguments->At(1));
+  if (!length_instance.IsSmi()) {
+    GrowableArray<const Object*> args;
+    args.Add(&length_instance);
+    Exceptions::ThrowByType(Exceptions::kIllegalArgument, args);
+  }
+  Smi& length = Smi::Handle();
+  length ^= length_instance.raw();
+  if (length.IsNull() || (length.Value() < 0)) {
+    GrowableArray<const Object*> args;
+    args.Add(&length);
+    Exceptions::ThrowByType(Exceptions::kIllegalArgument, args);
+  }
+  uint8_t* data = new uint8_t[length.Value()];
+  const ByteBuffer& new_array =
+      ByteBuffer::Handle(ByteBuffer::New(data, length.Value()));
+  arguments->SetReturn(new_array);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_getLength, 1) {
+  const ByteBuffer& array = ByteBuffer::CheckedHandle(arguments->At(0));
+  if (array.IsNull()) {
+    // TODO(asiva): Need to handle error cases.
+    UNIMPLEMENTED();
+    return;
+  }
+  const Smi& length = Smi::Handle(Smi::New(array.Length()));
+  arguments->SetReturn(length);
+}
+
+
+template<typename ValueType, typename ObjectType>
+static void GetIndexed(NativeArguments* arguments) {
+  const ByteBuffer& buffer = ByteBuffer::CheckedHandle(arguments->At(0));
+  const Instance& index_instance = Instance::CheckedHandle(arguments->At(1));
+  if (!index_instance.IsSmi()) {
+    GrowableArray<const Object*> args;
+    args.Add(&index_instance);
+    Exceptions::ThrowByType(Exceptions::kIllegalArgument, args);
+  }
+  Smi& index = Smi::Handle();
+  index ^= index_instance.raw();
+  if (buffer.IsNull() || index.IsNull()) {
+    // TODO(asiva): Need to handle error cases.
+    UNIMPLEMENTED();
+    return;
+  }
+  if ((index.Value() < 0) || (index.Value() >= buffer.Length())) {

[Ivan Posva, 2011/11/10 22:31:02]

You can still potentially read past the end of the buffer, no? For example you
have a 3 element byte buffer, and read a int32 from offset 0.

[cshapiro, 2011/11/11 00:37:53]

Yes.  Fixed.

+    GrowableArray<const Object*> arguments;
+    arguments.Add(&index);
+    Exceptions::ThrowByType(Exceptions::kIndexOutOfRange, arguments);
+  }
+  arguments->SetReturn(
+      ObjectType::Handle(ObjectType::New(buffer.At<ValueType>(index.Value()))));

[Ivan Posva, 2011/11/10 22:31:02]

Why are you assuming aligned addresses here and not in the set case?

[cshapiro, 2011/11/11 00:37:53]

Indeed, that is an oversight.  Fixed.

+}
+
+
+template<typename T> static bool HasType(const Object& obj);
+
+
+template<>
+bool HasType<Smi>(const Object& obj) {
+  return obj.IsSmi();
+}
+
+
+template<>
+bool HasType<Integer>(const Object& obj) {
+  return obj.IsInteger();
+}
+
+
+template<>
+bool HasType<Double>(const Object& obj) {
+  return obj.IsDouble();
+}
+
+
+static intptr_t Value(const Smi& obj) {
+  return obj.Value();
+}
+
+
+static int64_t Value(const Integer& obj) {
+  return obj.AsInt64Value();
+}
+
+
+static double Value(const Double& obj) {
+  return obj.value();
+}
+
+
+template<typename ValueType, typename ObjectType>
+static void SetIndexed(const NativeArguments* arguments) {
+  const ByteBuffer& buffer = ByteBuffer::CheckedHandle(arguments->At(0));
+  const Instance& index_instance = Instance::CheckedHandle(arguments->At(1));
+  if (!index_instance.IsSmi()) {
+    GrowableArray<const Object*> args;
+    args.Add(&index_instance);
+    Exceptions::ThrowByType(Exceptions::kIllegalArgument, args);
+  }
+  Smi& index = Smi::Handle();
+  index ^= index_instance.raw();
+  const Instance& value_instance = Instance::CheckedHandle(arguments->At(2));
+  if (buffer.IsNull() || index.IsNull()) {
+    // TODO(asiva): Need to handle error cases.
+    UNIMPLEMENTED();
+    return;
+  }
+  if ((index.Value() < 0) || (index.Value() >= buffer.Length())) {

[Ivan Posva, 2011/11/10 22:31:02]

ditto

[cshapiro, 2011/11/11 00:37:53]

Fixed.  This is all over array.cc, which is the origin of this method.  I'll
submit a cleanup for that file after this is submitted.

+    GrowableArray<const Object*> arguments;
+    arguments.Add(&index);
+    Exceptions::ThrowByType(Exceptions::kIndexOutOfRange, arguments);
+  }
+  if (!HasType<ObjectType>(value_instance)) {
+    GrowableArray<const Object*> args;
+    args.Add(&value_instance);
+    Exceptions::ThrowByType(Exceptions::kIllegalArgument, args);
+  }
+  ObjectType& value = ObjectType::Handle();
+  value ^= value_instance.raw();
+  buffer.SetUnalignedAt<ValueType>(index.Value(), Value(value));
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_getInt8, 2) {
+  GetIndexed<int8_t, Smi>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_setInt8, 3) {
+  SetIndexed<int8_t, Smi>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_getUint8, 2) {
+  GetIndexed<uint8_t, Smi>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_setUint8, 3) {
+  SetIndexed<uint8_t, Smi>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_getInt16, 2) {
+  GetIndexed<int16_t, Smi>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_setInt16, 3) {
+  SetIndexed<int16_t, Smi>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_getUint16, 2) {
+  GetIndexed<uint16_t, Smi>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_setUint16, 3) {
+  SetIndexed<uint16_t, Smi>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_getInt32, 2) {
+  GetIndexed<int32_t, Integer>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_setInt32, 3) {
+  SetIndexed<int32_t, Integer>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_getUint32, 2) {
+  GetIndexed<uint32_t, Integer>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_setUint32, 3) {
+  SetIndexed<uint32_t, Integer>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_getInt64, 2) {
+  GetIndexed<int64_t, Integer>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_setInt64, 3) {
+  SetIndexed<int64_t, Integer>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_getUint64, 2) {
+  UNIMPLEMENTED();  // TODO(cshapiro): need getter implementation.
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_setUint64, 3) {
+  UNIMPLEMENTED();  // TODO(cshapiro): need setter implementation.
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_getFloat32, 2) {
+  GetIndexed<float, Double>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_setFloat32, 3) {
+  SetIndexed<float, Double>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_getFloat64, 2) {
+  GetIndexed<double, Double>(arguments);
+}
+
+
+DEFINE_NATIVE_ENTRY(ByteBuffer_setFloat64, 3) {
+  SetIndexed<double, Double>(arguments);
+}
+
+}  // namespace dart