Function BM_EncodingSpaced

cpp/src/parquet/encoding_benchmark.cc:256–282

template <typename ParquetType>
static void BM_EncodingSpaced(benchmark::State& state, Encoding::type encoding) {
  using ArrowType = typename BM_SpacedEncodingTraits<ParquetType>::ArrowType;
  using ArrayType = typename BM_SpacedEncodingTraits<ParquetType>::ArrayType;
  using CType = typename BM_SpacedEncodingTraits<ParquetType>::CType;

  const int num_values = static_cast<int>(state.range(0));
  const double null_percent = static_cast<double>(state.range(1)) / 10000.0;

  auto rand = ::arrow::random::RandomArrayGenerator(1923);
  const auto array = rand.Numeric<ArrowType>(num_values, -100, 100, null_percent);
  const auto valid_bits = array->null_bitmap_data();
  const auto array_actual = ::arrow::internal::checked_pointer_cast<ArrayType>(array);
  const auto raw_values = array_actual->raw_values();
  // Guarantee the type cast between raw_values and input of PutSpaced.
  static_assert(sizeof(CType) == sizeof(*raw_values), "Type mismatch");
  // Cast only happens for BooleanType as it use UInt8 for the array data to match a bool*
  // input to PutSpaced.
  const auto src = reinterpret_cast<const CType*>(raw_values);

  auto encoder = MakeTypedEncoder<ParquetType>(encoding);
  for (auto _ : state) {
    encoder->PutSpaced(src, num_values, valid_bits, 0);
    encoder->FlushValues();
  }
  state.counters["null_percent"] = null_percent * 100;
  state.SetBytesProcessed(state.iterations() * num_values * sizeof(CType));
}

template <>
void BM_EncodingSpaced<BooleanType>(benchmark::State& state, Encoding::type encoding) {