Method Sum

r/src/altrep.cpp:383–415

  static SEXP Max(SEXP alt, Rboolean narm) { return MinMax<false>(alt, narm); }

  static SEXP Sum(SEXP alt, Rboolean narm) {
    if (IsMaterialized(alt)) {
      return nullptr;
    }

    using data_type = typename std::conditional<sexp_type == REALSXP, double, int>::type;

    const auto& chunked_array = GetChunkedArray(alt);
    bool na_rm = narm == TRUE;
    auto null_count = chunked_array->null_count();

    if (!na_rm && null_count > 0) {
      return cpp11::as_sexp(cpp11::na<data_type>());
    }
    auto options = NaRmOptions(na_rm);

    const auto& sum =
        ValueOrStop(arrow::compute::CallFunction("sum", {chunked_array}, options.get()));

    if (sexp_type == INTSXP) {
      // When calling the "sum" function on an int32 array, we get an Int64 scalar
      // in case of overflow, make it a double like R
      int64_t value = internal::checked_cast<const Int64Scalar&>(*sum.scalar()).value;
      if (value <= INT32_MIN || value > INT32_MAX) {
        return Rf_ScalarReal(static_cast<double>(value));
      } else {
        return Rf_ScalarInteger(static_cast<int>(value));
      }
    } else {
      return Rf_ScalarReal(
          internal::checked_cast<const DoubleScalar&>(*sum.scalar()).value);
    }
  }
};
template <int sexp_type>
R_altrep_class_t AltrepVectorPrimitive<sexp_type>::class_t;