Use ByteArray's native for Socket and File.

runtime/lib/byte_array.cc

 // 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.
 
 #include "vm/bootstrap_natives.h"
 
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 
@@ skipping 12 matching lines @@
     GrowableArray<const Object*> args;
     args.Add(&length);
     Exceptions::ThrowByType(Exceptions::kIllegalArgument, args);
   }
   const InternalByteArray& new_array =
       InternalByteArray::Handle(InternalByteArray::New(length.Value()));
   arguments->SetReturn(new_array);
 }
 
 
+DEFINE_NATIVE_ENTRY(ByteArray_copyFromByteArray, 5) {
+  ByteArray& dst = ByteArray::CheckedHandle(arguments->At(0));
+  GET_NATIVE_ARGUMENT(ByteArray, src, arguments->At(1));
+  GET_NATIVE_ARGUMENT(Smi, src_start, arguments->At(2));
+  GET_NATIVE_ARGUMENT(Smi, dst_start, arguments->At(3));
+  GET_NATIVE_ARGUMENT(Smi, count, arguments->At(4));
+  intptr_t icount = count.Value();

[cshapiro, 2012/01/27 23:00:04]

I think the Value() calls are compiled away so you do not need to do the
subexpression elimination on your own.

[Anders Johnsen, 2012/01/27 23:42:39]

Done.

+  if (icount < 0) {
+    GrowableArray<const Object*> args;
+    Exceptions::ThrowByType(Exceptions::kIllegalArgument, args);
+  }
+  if (icount == 0) {
+    return;
+  }
+  intptr_t isrc_start = src_start.Value();
+  intptr_t idst_start = dst_start.Value();
+  if ((isrc_start < 0) || ((isrc_start + icount) > src.Length())) {
+    GrowableArray<const Object*> arguments;
+    arguments.Add(&src_start);
+    Exceptions::ThrowByType(Exceptions::kIndexOutOfRange, arguments);
+  }
+  if ((idst_start < 0) || ((idst_start + icount) > dst.Length())) {
+    GrowableArray<const Object*> arguments;
+    arguments.Add(&dst_start);
+    Exceptions::ThrowByType(Exceptions::kIndexOutOfRange, arguments);
+  }
+  ByteArray::Copy(dst, idst_start, src, isrc_start, icount);
+}
+
+
 static void RangeCheck(const ByteArray& array, const Smi& index,
                        intptr_t num_bytes) {
   if ((index.Value() < 0) || ((index.Value() + num_bytes) > array.Length())) {
     GrowableArray<const Object*> arguments;
     arguments.Add(&index);
     Exceptions::ThrowByType(Exceptions::kIndexOutOfRange, arguments);
   }
 }
 
 
@@ skipping 206 matching lines @@
 DEFINE_NATIVE_ENTRY(ExternalByteArray_getFloat64, 2) {
   GETTER(ExternalByteArray, Double, double);
 }
 
 
 DEFINE_NATIVE_ENTRY(ExternalByteArray_setFloat64, 3) {
   SETTER(ExternalByteArray, Double, value, double);
 }
 
 }  // namespace dart