Function TransferInt

cpp/src/parquet/arrow/reader_internal.cc:424–448

template <typename ArrowType, typename ParquetType>
Status TransferInt(RecordReader* reader,
                   std::unique_ptr<::parquet::ColumnChunkMetaData> metadata,
                   const ReaderContext* ctx, const std::shared_ptr<Field>& field,
                   Datum* out) {
  using ArrowCType = typename ArrowType::c_type;
  using ParquetCType = typename ParquetType::c_type;
  int64_t length = reader->values_written();
  ARROW_ASSIGN_OR_RAISE(auto data,
                        ::arrow::AllocateBuffer(length * sizeof(ArrowCType), ctx->pool));

  auto values = reinterpret_cast<const ParquetCType*>(reader->values());
  auto out_ptr = reinterpret_cast<ArrowCType*>(data->mutable_data());
  std::copy(values, values + length, out_ptr);
  int64_t null_count = 0;
  std::vector<std::shared_ptr<Buffer>> buffers = {nullptr, std::move(data)};
  if (field->nullable()) {
    null_count = reader->null_count();
    buffers[0] = reader->ReleaseIsValid();
  }
  auto array_data =
      ::arrow::ArrayData::Make(field->type(), length, std::move(buffers), null_count);
  AttachStatistics<ArrowType, ParquetType>(array_data.get(), std::move(metadata), ctx);
  *out = std::make_shared<ArrayType<ArrowType>>(std::move(array_data));
  return Status::OK();
}

template <typename ArrowType, typename ParquetType>
std::shared_ptr<Array> TransferZeroCopy(