Document the ByteArray types and reconcile with the implementation.

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/bigint_operations.h"
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
@@ skipping 43 matching lines @@
   GETTER_ARGUMENTS(ArrayT, ValueT);                                     \
   RangeCheck(array, index.Value(), sizeof(ValueT));                     \
   ValueT result;                                                        \
   ByteArray::Copy(&result, array, index.Value(), sizeof(ValueT));       \
   arguments->SetReturn(ObjectT::Handle(ObjectT::New(result)));
 
 
 #define UNALIGNED_SETTER(ArrayT, ObjectT, Getter, ValueT)               \
   SETTER_ARGUMENTS(ArrayT, ObjectT, ValueT);                            \
   RangeCheck(array, index.Value(), sizeof(ValueT));                     \
-  ValueT src = value_object.Getter();                                  \
-  ByteArray::Copy(array, index.Value(), &src, sizeof(ValueT));
+  ValueT src = value_object.Getter();                                   \
+  ByteArray::Copy(array, index.Value(), &src, sizeof(ValueT));          \
+  Integer& result = Integer::Handle();                                  \
+  result ^= Integer::New(index.Value() + sizeof(ValueT));               \
+  arguments->SetReturn(result);
 
 
 #define UINT64_TO_INTEGER(value, integer)                               \
   if (value > static_cast<uint64_t>(Mint::kMaxValue)) {                 \
     result = BigintOperations::NewFromUint64(value);                    \
   } else if (value > static_cast<uint64_t>(Smi::kMaxValue)) {           \
     result = Mint::New(value);                                          \
   } else {                                                              \
     result = Smi::New(value);                                           \
   }
@@ skipping 38 matching lines @@
   uint64_t value;                                                       \
   INTEGER_TO_UINT64(value_object, value);                               \
   array.SetAt(index.Value(), value);
 
 
 #define UNALIGNED_SETTER_UINT64(ArrayT)                                 \
   SETTER_ARGUMENTS(ArrayT, Integer, uint64_t);                          \
   RangeCheck(array, index.Value(), sizeof(uint64_t));                   \
   uint64_t value;                                                       \
   INTEGER_TO_UINT64(value_object, value);                               \
-  ByteArray::Copy(array, index.Value(), &value, sizeof(uint64_t));
+  ByteArray::Copy(array, index.Value(), &value, sizeof(uint64_t));      \
+  Integer& result = Integer::Handle();                                  \
+  result ^= Integer::New(index.Value() + sizeof(uint64_t));             \
+  arguments->SetReturn(result);
 
 
 DEFINE_NATIVE_ENTRY(ByteArray_getLength, 1) {
   GET_NATIVE_ARGUMENT(ByteArray, array, arguments->At(0));
   const Smi& length = Smi::Handle(Smi::New(array.Length()));
   arguments->SetReturn(length);
 }
 
 
 DEFINE_NATIVE_ENTRY(ByteArray_getInt8, 2) {
@@ skipping 478 matching lines @@
 DEFINE_NATIVE_ENTRY(ExternalFloat64Array_getIndexed, 2) {
   GETTER(ExternalFloat64Array, Double, double);
 }
 
 
 DEFINE_NATIVE_ENTRY(ExternalFloat64Array_setIndexed, 3) {
   SETTER(ExternalFloat64Array, Double, value, double);
 }
 
 }  // namespace dart