Method GenerateComments

cpp/src/arrow/acero/tpch_node.cc:316–340

}

Result<Datum> TpchPseudotext::GenerateComments(size_t num_comments, size_t min_length,
                                               size_t max_length,
                                               random::pcg32_fast& rng) {
  RETURN_NOT_OK(EnsureInitialized(rng));
  std::uniform_int_distribution<size_t> length_dist(min_length, max_length);
  ARROW_ASSIGN_OR_RAISE(std::unique_ptr<Buffer> offset_buffer,
                        AllocateBuffer(sizeof(int32_t) * (num_comments + 1)));
  int32_t* offsets = reinterpret_cast<int32_t*>(offset_buffer->mutable_data());
  offsets[0] = 0;
  for (size_t i = 1; i <= num_comments; i++)
    offsets[i] = offsets[i - 1] + static_cast<int32_t>(length_dist(rng));

  ARROW_ASSIGN_OR_RAISE(std::unique_ptr<Buffer> comment_buffer,
                        AllocateBuffer(offsets[num_comments]));
  char* comments = reinterpret_cast<char*>(comment_buffer->mutable_data());
  for (size_t i = 0; i < num_comments; i++) {
    size_t length = offsets[i + 1] - offsets[i];
    std::uniform_int_distribution<size_t> offset_dist(0, kTextBytes - length);
    size_t offset_in_text = offset_dist(rng);
    std::memcpy(comments + offsets[i], text_->data() + offset_in_text, length);
  }
  ArrayData ad(utf8(), num_comments,
               {nullptr, std::move(offset_buffer), std::move(comment_buffer)});
  return ad;
}

bool TpchPseudotext::GenerateWord(int64_t& offset, random::pcg32_fast& rng, char* arr,
                                  const char** words, size_t num_choices) {