Function BM_DecodingByteArraySpaced

cpp/src/parquet/encoding_benchmark.cc:859–894

BENCHMARK(BM_DeltaLengthDecodingByteArray)->Apply(ByteArrayCustomArguments);

static void BM_DecodingByteArraySpaced(benchmark::State& state, Encoding::type encoding) {
  const double null_percent = 0.02;

  auto rand = ::arrow::random::RandomArrayGenerator(0);
  int32_t max_length = static_cast<int32_t>(state.range(0));
  int32_t num_values = static_cast<int32_t>(state.range(1));
  const auto array = rand.String(num_values, /* min_length */ 0,
                                 /* max_length */ max_length, null_percent);
  const auto valid_bits = array->null_bitmap_data();
  const int null_count = static_cast<int>(array->null_count());
  const auto array_actual =
      ::arrow::internal::checked_pointer_cast<::arrow::StringArray>(array);

  std::vector<ByteArray> byte_arrays;
  byte_arrays.reserve(array_actual->length());
  for (int i = 0; i < array_actual->length(); ++i) {
    byte_arrays.emplace_back(array_actual->GetView(i));
  }

  auto encoder = MakeTypedEncoder<ByteArrayType>(encoding);
  encoder->PutSpaced(byte_arrays.data(), num_values, valid_bits, 0);
  std::shared_ptr<Buffer> buf = encoder->FlushValues();

  auto decoder = MakeTypedDecoder<ByteArrayType>(encoding);
  std::vector<uint8_t> decode_values(num_values * sizeof(ByteArray));
  auto decode_buf = reinterpret_cast<ByteArray*>(decode_values.data());
  for (auto _ : state) {
    decoder->SetData(num_values - null_count, buf->data(), static_cast<int>(buf->size()));
    decoder->DecodeSpaced(decode_buf, num_values, null_count, valid_bits, 0);
    ::benchmark::DoNotOptimize(decode_buf);
  }
  state.counters["null_percent"] = null_percent * 100;
  state.SetItemsProcessed(state.iterations() * array_actual->length());
  state.SetBytesProcessed(state.iterations() * (array_actual->value_data()->size() +
                                                array_actual->value_offsets()->size()));
}

static void BM_PlainDecodingSpacedByteArray(benchmark::State& state) {
  BM_DecodingByteArraySpaced(state, Encoding::PLAIN);