Function MaskToBitmap

python/pyarrow/src/arrow/python/numpy_to_arrow.cc:158–173

Returns null count

// Returns null count
int64_t MaskToBitmap(PyArrayObject* mask, int64_t length, uint8_t* bitmap) {
  int64_t null_count = 0;

  if (!PyArray_Check(mask)) return -1;

  Ndarray1DIndexer<uint8_t> mask_values(mask);
  for (int i = 0; i < length; ++i) {
    if (mask_values[i]) {
      ++null_count;
      bit_util::ClearBit(bitmap, i);
    } else {
      bit_util::SetBit(bitmap, i);
    }
  }
  return null_count;
}

}  // namespace