An efficient way to convert ByteData in Dart to unsigned char* in C++?

Question

I'm doing it in this way:

Pointer<Uint8> _byteDataToPointer(ByteData byteData) {
  final uint8List = byteData.buffer.asUint8List();
  final length = uint8List.lengthInBytes;
  final result = allocate<Uint8>(count: length);

  for (var i = 0; i < length; ++i) {
    result[i] = uint8List[i];
  }

  return result;
}

Is there a more efficient way like JNIEnv::GetByteArrayRegion in JNI?

Thank you very much!

Answer 1

This is always going to involve a copy, so is there something more efficient than your for loop? Maybe.

After allocating your Uint8Pointer use asTypedList to convert it to a Uint8List . Now you have access to its copy primitive like setAll and setRange to copy from the source to the destination.

What's the original source of the ByteData ? If you knew the size in advance, could you allocate the Uint8Pointer first, convert to typed data and then read directly into that?