Function BitLength

cpp/src/arrow/util/bitmap.h:453–458

  template <size_t N>
  static int64_t BitLength(const std::array<Bitmap, N>& bitmaps) {
    for (size_t i = 1; i < N; ++i) {
      assert(bitmaps[i].length() == bitmaps[0].length());
    }
    return bitmaps[0].length();
  }

  const uint8_t* data_ = NULLPTR;
  uint8_t* mutable_data_ = NULLPTR;