Function test_arrow_altrep_copy_by_region

r/src/altrep.cpp:1199–1231

[[arrow::export]]

// [[arrow::export]]
sexp test_arrow_altrep_copy_by_region(sexp x, R_xlen_t region_size) {
  if (!is_arrow_altrep(x)) {
    stop("x is not arrow ALTREP");
  }

  R_xlen_t n = Rf_xlength(x);

  if (TYPEOF(x) == INTSXP) {
    cpp11::writable::integers out(Rf_xlength(x));
    cpp11::writable::integers buf_shelter(region_size);
    int* buf = INTEGER(buf_shelter);
    for (R_xlen_t i = 0; i < n; i++) {
      if ((i % region_size) == 0) {
        INTEGER_GET_REGION(x, i, region_size, buf);
      }
      out[i] = buf[i % region_size];
    }
    return out;
  } else if (TYPEOF(x) == REALSXP) {
    cpp11::writable::doubles out(Rf_xlength(x));
    cpp11::writable::doubles buf_shelter(region_size);
    double* buf = REAL(buf_shelter);
    for (R_xlen_t i = 0; i < n; i++) {
      if ((i % region_size) == 0) {
        REAL_GET_REGION(x, i, region_size, buf);
      }
      out[i] = buf[i % region_size];
    }
    return out;
  } else {
    return R_NilValue;
  }
}

// [[arrow::export]]
sexp test_arrow_altrep_copy_by_dataptr(sexp x) {