gty404 commented on code in PR #54: URL: https://github.com/apache/iceberg-cpp/pull/54#discussion_r2022288956
########## src/iceberg/transform.h: ########## @@ -0,0 +1,119 @@ +/* + * 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. + */ + +#pragma once + +/// \file iceberg/transform.h + +#include <cstdint> +#include <memory> + +#include "iceberg/arrow_c_data.h" +#include "iceberg/error.h" +#include "iceberg/expected.h" +#include "iceberg/iceberg_export.h" +#include "iceberg/type_fwd.h" +#include "iceberg/util/formattable.h" + +namespace iceberg { + +/// \brief Transform types used for partitioning +enum class TransformType { + /// Used to represent some customized transform that can't be recognized or supported + /// now. + kUnknown, + /// Equal to source value, unmodified + kIdentity, + /// Hash of value, mod `N` + kBucket, + /// Value truncated to width `W` + kTruncate, + /// Extract a date or timestamp year, as years from 1970 + kYear, + /// Extract a date or timestamp month, as months from 1970-01-01 + kMonth, + /// Extract a date or timestamp day, as days from 1970-01-01 + kDay, + /// Extract a timestamp hour, as hours from 1970-01-01 00:00:00 + kHour, + /// Always produces `null` + kVoid, +}; + +/// \brief Get the relative transform name +constexpr std::string_view ToString(TransformType type) { + switch (type) { + case TransformType::kUnknown: + return "Unknown"; + case TransformType::kIdentity: + return "Identity"; + case TransformType::kBucket: + return "Bucket"; + case TransformType::kTruncate: + return "Truncate"; + case TransformType::kYear: + return "Year"; + case TransformType::kMonth: + return "Month"; + case TransformType::kDay: + return "Day"; + case TransformType::kHour: + return "Hour"; + case TransformType::kVoid: + return "Void"; + default: + return "Invalid"; + } +} + +/// \brief A transform function used for partitioning. +class ICEBERG_EXPORT TransformFunction : public util::Formattable { + public: + explicit TransformFunction(TransformType type); + /// \brief Transform an input array to a new array + virtual expected<ArrowArray, Error> Transform(const ArrowArray& data) = 0; + /// \brief Get the transform type + virtual TransformType transform_type() const; + + std::string ToString() const override; + + friend bool operator==(const TransformFunction& lhs, const TransformFunction& rhs) { + return lhs.Equals(rhs); + } + + friend bool operator!=(const TransformFunction& lhs, const TransformFunction& rhs) { + return !(lhs == rhs); + } + + private: + /// \brief Compare two partition specs for equality. + [[nodiscard]] virtual bool Equals(const TransformFunction& other) const; + + TransformType transform_type_; +}; + +class IdentityTransformFunction : public TransformFunction { + public: + IdentityTransformFunction() : TransformFunction(TransformType::kIdentity) {} + expected<ArrowArray, Error> Transform(const ArrowArray& input) override { + return input; Review Comment: The implementation of identify transform is currently only used in test, I will implement these Transforms in the next pr. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
