FlattenExecutor.h

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/*****************************************************************************
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 *  Copyright 2018 Rice University                                           *
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#ifndef FLATTEN_QUERY_EXEC_H
#define FLATTEN_QUERY_EXEC_H

#include "ComputeExecutor.h"
#include "TupleSetMachine.h"
#include "TupleSet.h"
#include <vector>


namespace pdb {

// runs an appending 1 operation
class FlattenExecutor : public ComputeExecutor {

private:
    // this is the output TupleSet that we return
    TupleSetPtr output;

    // the attribute to operate on
    int whichAtt;

    // the output attribute
    int outAtt;

    // to setup the output tuple set
    TupleSetSetupMachine myMachine;

    // the list of counts for matches of each of the input tuples
    std::vector<uint32_t> counts;

public:
    // currently, we just ignore the extra parameter to the filter if we get it
    FlattenExecutor(TupleSpec& inputSchema,
                    TupleSpec& attsToOperateOn,
                    TupleSpec& attsToIncludeInOutput,
                    ComputeInfoPtr)
        : myMachine(inputSchema, attsToIncludeInOutput) {

        // this is the input attribute that we will process
        output = std::make_shared<TupleSet>();
        std::vector<int> matches = myMachine.match(attsToOperateOn);
        whichAtt = matches[0];
        outAtt = attsToIncludeInOutput.getAtts().size();
    }

    FlattenExecutor(TupleSpec& inputSchema,
                    TupleSpec& attsToOperateOn,
                    TupleSpec& attsToIncludeInOutput)
        : myMachine(inputSchema, attsToIncludeInOutput) {

        // this is the input attribute that we will process
        output = std::make_shared<TupleSet>();
        std::vector<int> matches = myMachine.match(attsToOperateOn);
        whichAtt = matches[0];
        outAtt = attsToIncludeInOutput.getAtts().size();
    }

    TupleSetPtr process(TupleSetPtr input) override {

        // std :: cout << "FlattenExecutor: to process a tuple set" << std :: endl;

        std::vector<Vector<Handle<Object>>> inputVecData =
            input->getColumn<Vector<Handle<Object>>>(whichAtt);

        // redo the vector of counts if it's not the correct size
        if (counts.size() != inputVecData.size()) {
            counts.resize(inputVecData.size());
        }

        // get counts for replication
        int numFlattenedRows = 0;
        for (int i = 0; i < inputVecData.size(); i++) {
            Vector<Handle<Object>>& myVec = inputVecData[i];
            int mySize = myVec.size();
            // std :: cout << "mySize is" << mySize << std :: endl;
            counts[i] = mySize;
            numFlattenedRows += mySize;
        }

        // replicates other columns
        myMachine.replicate(input, output, counts, 0);

        // add new column
        if (!output->hasColumn(outAtt)) {
            std::vector<Handle<Object>>* outColumn = new std::vector<Handle<Object>>();
            output->addColumn(outAtt, outColumn, true);
        }

        // get the output column
        std::vector<Handle<Object>>& outColumn = output->getColumn<Handle<Object>>(outAtt);
        // loop over to set the rows
        outColumn.resize(numFlattenedRows);
        int overallCounter = 0;
        size_t mySize = inputVecData.size();
        for (int i = 0; i < mySize; i++) {
            Vector<Handle<Object>>& myVec = inputVecData[i];
            Handle<Object>* myRawData = myVec.c_ptr();
            size_t myVecSize = myVec.size();
            for (int j = 0; j < myVecSize; j++) {
                outColumn[overallCounter] = myRawData[j];
                overallCounter++;
            }
        }

        return output;
    }


    std::string getType() override {
        return "FLATTEN";
    }
};
}

#endif