Function GetDictDecoder

cpp/src/parquet/encoding_test.cc:879–902

template <typename T>
void GetDictDecoder(DictEncoder<T>* encoder, int64_t num_values,
                    std::shared_ptr<Buffer>* out_values,
                    std::shared_ptr<Buffer>* out_dict, const ColumnDescriptor* descr,
                    std::unique_ptr<TypedDecoder<T>>* out_decoder) {
  auto decoder = MakeDictDecoder<T>(descr);
  auto buf = encoder->FlushValues();
  auto dict_buf = AllocateBuffer(default_memory_pool(), encoder->dict_encoded_size());
  encoder->WriteDict(dict_buf->mutable_data());

  auto dict_decoder = MakeTypedDecoder<T>(Encoding::PLAIN, descr);
  dict_decoder->SetData(encoder->num_entries(), dict_buf->data(),
                        static_cast<int>(dict_buf->size()));

  decoder->SetData(static_cast<int>(num_values), buf->data(),
                   static_cast<int>(buf->size()));
  decoder->SetDict(dict_decoder.get());

  *out_values = buf;
  *out_dict = dict_buf;
  ASSERT_NE(decoder, nullptr);
  auto released = dynamic_cast<TypedDecoder<T>*>(decoder.release());
  ASSERT_NE(released, nullptr);
  *out_decoder = std::unique_ptr<TypedDecoder<T>>(released);
}

template <typename ParquetType>
class EncodingAdHocTyped : public ::testing::Test {