src: convert BE-utf16-string to LE before search

On Big Endian platforms v8 strings are need to converted
to Little Endian before searching in utf16le buffer

Fixes: #3283
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: Michael Dawson <mhdawson@ca.ibm.com>
PR-URL: #3295

src/node_buffer.cc

@@ -842,11 +842,27 @@ void IndexOfString(const FunctionCallbackInfo<Value>& args) {
  return args.GetReturnValue().Set(-1);
  }
 
- result = SearchString(reinterpret_cast<const uint16_t*>(haystack),
- haystack_length / 2,
- reinterpret_cast<const uint16_t*>(*needle_value),
- needle_value.length(),
- offset / 2);
+ if (IsBigEndian()) {
+ StringBytes::InlineDecoder decoder;
+ decoder.Decode(Environment::GetCurrent(args), needle, args[3], UCS2);
+ const uint16_t* decoded_string =
+ reinterpret_cast<const uint16_t*>(decoder.out());
+
+ if (decoded_string == nullptr)
+ return args.GetReturnValue().Set(-1);
+
+ result = SearchString(reinterpret_cast<const uint16_t*>(haystack),
+ haystack_length / 2,
+ decoded_string,
+ decoder.size() / 2,
+ offset / 2);
+ } else {
+ result = SearchString(reinterpret_cast<const uint16_t*>(haystack),
+ haystack_length / 2,
+ reinterpret_cast<const uint16_t*>(*needle_value),
+ needle_value.length(),
+ offset / 2);
+ }
  result *= 2;
  } else if (enc == UTF8) {
  String::Utf8Value needle_value(needle);