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/**
* 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.
*/
#ifndef ORC_SCHEMA_EVOLUTION_HH
#define ORC_SCHEMA_EVOLUTION_HH
#include "orc/Type.hh"
#include <unordered_map>
#include <unordered_set>
namespace orc {
/**
* Utility class to compare read type and file type to match their columns
* and check type conversion.
*/
class SchemaEvolution {
public:
SchemaEvolution(const std::shared_ptr<Type>& readType, const Type* fileType);
// get read type by column id from file type. or return the file type if
// read type is not provided (i.e. no schema evolution requested).
const Type* getReadType(const Type& fileType) const;
// check if we need to convert file type to read type for primitive type.
bool needConvert(const Type& fileType) const;
// check if the PPD conversion is safe
bool isSafePPDConversion(uint64_t columnId) const;
// return selected read type
const Type* getReadType() const {
return readType.get();
}
private:
void buildConversion(const Type* readType, const Type* fileType);
void buildSafePPDConversionMap(const Type* readType, const Type* fileType);
private:
const std::shared_ptr<Type> readType;
std::unordered_map<uint64_t, const Type*> readTypeMap;
std::unordered_set<uint64_t> safePPDConversionMap;
};
} // namespace orc
#endif // ORC_SCHEMA_EVOLUTION_HH
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