kszucs commented on a change in pull request #8088: URL: https://github.com/apache/arrow/pull/8088#discussion_r492187679
########## File path: cpp/src/arrow/util/converter.h ########## @@ -0,0 +1,348 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you 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. + +#include <string> +#include <utility> +#include <vector> + +#include "arrow/array.h" +#include "arrow/builder.h" +#include "arrow/chunked_array.h" +#include "arrow/status.h" +#include "arrow/type.h" +#include "arrow/type_traits.h" +#include "arrow/util/checked_cast.h" + +#include "arrow/visitor_inline.h" + +namespace arrow { +namespace internal { + +template <typename Input, typename Options, typename Self> +class Converter { + public: + using InputType = Input; + using OptionsType = Options; + + virtual ~Converter() = default; + + virtual Status Initialize(std::shared_ptr<DataType> type, + std::shared_ptr<ArrayBuilder> builder, + const std::vector<std::shared_ptr<Self>>& children, + OptionsType options) { + type_ = std::move(type); + builder_ = std::move(builder); + children_ = std::move(children); + options_ = std::move(options); + return Init(); + } + + virtual Status Init() { return Status::OK(); } + + virtual Status Append(InputType value) { + return Status::NotImplemented("Converter not implemented for type ", + type()->ToString()); + } + + const std::shared_ptr<ArrayBuilder>& builder() const { return builder_; } + + const std::shared_ptr<DataType>& type() const { return type_; } + + OptionsType options() const { return options_; } + + const std::vector<std::shared_ptr<Self>>& children() const { return children_; } + + Status Reserve(int64_t additional_capacity) { + return builder_->Reserve(additional_capacity); + } + + Status AppendNull() { return builder_->AppendNull(); } + + virtual Result<std::shared_ptr<Array>> ToArray() { return builder_->Finish(); } + + virtual Result<std::shared_ptr<Array>> ToArray(int64_t length) { + ARROW_ASSIGN_OR_RAISE(auto arr, this->ToArray()); + return arr->Slice(0, length); + } + + protected: + std::shared_ptr<DataType> type_; + std::shared_ptr<ArrayBuilder> builder_; + std::vector<std::shared_ptr<Self>> children_; + OptionsType options_; +}; + +template <typename T, typename BaseConverter> +class PrimitiveConverter : public BaseConverter { + public: + using BuilderType = typename TypeTraits<T>::BuilderType; + + Status Init() override { + primitive_type_ = checked_cast<const T*>(this->type_.get()); + primitive_builder_ = checked_cast<BuilderType*>(this->builder_.get()); + return Status::OK(); + } + + protected: + const T* primitive_type_; + BuilderType* primitive_builder_; +}; + +template <typename T, typename BaseConverter> +class ListConverter : public BaseConverter { Review comment: Updated. ########## File path: cpp/src/arrow/util/converter.h ########## @@ -0,0 +1,348 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you 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. + +#include <string> +#include <utility> +#include <vector> + +#include "arrow/array.h" +#include "arrow/builder.h" +#include "arrow/chunked_array.h" +#include "arrow/status.h" +#include "arrow/type.h" +#include "arrow/type_traits.h" +#include "arrow/util/checked_cast.h" + +#include "arrow/visitor_inline.h" + +namespace arrow { +namespace internal { + +template <typename Input, typename Options, typename Self> +class Converter { + public: + using InputType = Input; + using OptionsType = Options; + + virtual ~Converter() = default; + + virtual Status Initialize(std::shared_ptr<DataType> type, + std::shared_ptr<ArrayBuilder> builder, + const std::vector<std::shared_ptr<Self>>& children, + OptionsType options) { + type_ = std::move(type); + builder_ = std::move(builder); + children_ = std::move(children); + options_ = std::move(options); + return Init(); + } + + virtual Status Init() { return Status::OK(); } + + virtual Status Append(InputType value) { + return Status::NotImplemented("Converter not implemented for type ", + type()->ToString()); + } + + const std::shared_ptr<ArrayBuilder>& builder() const { return builder_; } + + const std::shared_ptr<DataType>& type() const { return type_; } + + OptionsType options() const { return options_; } + + const std::vector<std::shared_ptr<Self>>& children() const { return children_; } + + Status Reserve(int64_t additional_capacity) { + return builder_->Reserve(additional_capacity); + } + + Status AppendNull() { return builder_->AppendNull(); } + + virtual Result<std::shared_ptr<Array>> ToArray() { return builder_->Finish(); } + + virtual Result<std::shared_ptr<Array>> ToArray(int64_t length) { + ARROW_ASSIGN_OR_RAISE(auto arr, this->ToArray()); + return arr->Slice(0, length); + } + + protected: + std::shared_ptr<DataType> type_; + std::shared_ptr<ArrayBuilder> builder_; + std::vector<std::shared_ptr<Self>> children_; + OptionsType options_; +}; + +template <typename T, typename BaseConverter> +class PrimitiveConverter : public BaseConverter { + public: + using BuilderType = typename TypeTraits<T>::BuilderType; + + Status Init() override { + primitive_type_ = checked_cast<const T*>(this->type_.get()); + primitive_builder_ = checked_cast<BuilderType*>(this->builder_.get()); + return Status::OK(); + } + + protected: + const T* primitive_type_; + BuilderType* primitive_builder_; +}; + +template <typename T, typename BaseConverter> +class ListConverter : public BaseConverter { + public: + using BuilderType = typename TypeTraits<T>::BuilderType; + + Status Init() override { + list_type_ = checked_cast<const T*>(this->type_.get()); + list_builder_ = checked_cast<BuilderType*>(this->builder_.get()); + value_converter_ = this->children_[0]; + return Status::OK(); + } + + protected: + const T* list_type_; + BuilderType* list_builder_; + std::shared_ptr<BaseConverter> value_converter_; +}; + +template <typename BaseConverter> +class StructConverter : public BaseConverter { + public: + Status Init() override { + struct_type_ = checked_cast<const StructType*>(this->type_.get()); + struct_builder_ = checked_cast<StructBuilder*>(this->builder_.get()); + return Status::OK(); + } + + protected: + const StructType* struct_type_; + StructBuilder* struct_builder_; +}; + +template <typename U, typename BaseConverter> +class DictionaryConverter : public BaseConverter { + public: + using BuilderType = DictionaryBuilder<U>; + + Status Init() override { + dict_type_ = checked_cast<const DictionaryType*>(this->type_.get()); + value_type_ = checked_cast<const U*>(dict_type_->value_type().get()); + value_builder_ = checked_cast<BuilderType*>(this->builder_.get()); + return Status::OK(); + } + + protected: + const DictionaryType* dict_type_; + const U* value_type_; + BuilderType* value_builder_; +}; + +template <typename Converter, template <typename...> class ConverterTrait> +struct MakeConverterImpl; + +template <typename Converter, template <typename...> class ConverterTrait> +static Result<std::shared_ptr<Converter>> MakeConverter( + std::shared_ptr<DataType> type, MemoryPool* pool, + typename Converter::OptionsType options) { + std::shared_ptr<Converter> out; + MakeConverterImpl<Converter, ConverterTrait> visitor = {type, pool, options, &out}; + ARROW_RETURN_NOT_OK(VisitTypeInline(*type, &visitor)); + return out; +} Review comment: Updated. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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