ParquetTimeEncoder.h

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/*
 * Copyright 2022 HEAVY.AI, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include "ParquetInPlaceEncoder.h"

namespace foreign_storage {

// The following semantics apply to the templated types below.
//
// V - type of omnisci data
// T - physical type of parquet data
// conversion_denominator - the denominator constant used in converting parquet to omnisci
// data
// NullType - type of encoded null
//
// The `conversion_denominator` template is used instead of a class member to
// specify it at compile-time versus run-time. In testing this has a major
// impact on the runtime of the conversion performed by this encoder since the
// compiler can significantly optimize if this is known at compile time.
template <typename V, typename T, T conversion_denominator, typename NullType = V>
class ParquetTimeEncoder : public TypedParquetInPlaceEncoder<V, T, NullType> {
 public:
  ParquetTimeEncoder(Data_Namespace::AbstractBuffer* buffer,
                     const ColumnDescriptor* column_desciptor,
                     const parquet::ColumnDescriptor* parquet_column_descriptor)
      : TypedParquetInPlaceEncoder<V, T, NullType>(buffer,
                                                   column_desciptor,
                                                   parquet_column_descriptor) {
    CHECK(parquet_column_descriptor->logical_type()->is_time());
  }

  void encodeAndCopy(const int8_t* parquet_data_bytes,
                     int8_t* omnisci_data_bytes) override {
    const auto& parquet_data_value = reinterpret_cast<const T*>(parquet_data_bytes)[0];
    auto& omnisci_data_value = reinterpret_cast<V*>(omnisci_data_bytes)[0];
    omnisci_data_value = parquet_data_value / conversion_denominator;
  }
};

}  // namespace foreign_storage