Method ReadAt

cpp/src/arrow/io/file.cc:136–144

  }

  Result<int64_t> ReadAt(int64_t position, int64_t nbytes, void* out) {
    RETURN_NOT_OK(CheckClosed());
    RETURN_NOT_OK(internal::ValidateRange(position, nbytes));
    // ReadAt() leaves the file position undefined, so require that we seek
    // before calling Read() or Write().
    need_seeking_.store(true);
    return ::arrow::internal::FileReadAt(fd_.fd(), reinterpret_cast<uint8_t*>(out),
                                         position, nbytes);
  }

  Status Seek(int64_t pos) {
    RETURN_NOT_OK(CheckClosed());