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package com.clickhouse.client.api.data_formats;

import com.clickhouse.client.api.data_formats.internal.AbstractBinaryFormatReader;
import com.clickhouse.client.api.data_formats.internal.BinaryStreamReader;
import com.clickhouse.client.api.query.QuerySettings;
import com.clickhouse.data.ClickHouseColumn;

import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * For the backward compatibility server will not send TZ id in column type. Client should send version to a server
 * to get the correct column type.
 * (see: https://github.com/ClickHouse/ClickHouse/issues/38209)
 */
public class NativeFormatReader extends AbstractBinaryFormatReader {

    private Block currentBlock;

    private int blockRowIndex;

    public NativeFormatReader(InputStream inputStream, QuerySettings settings,
                              BinaryStreamReader.ByteBufferAllocator byteBufferAllocator) {
        super(inputStream, settings, null, byteBufferAllocator);
        readNextRecord();
    }

    @Override
    public boolean readRecord(Map record) throws IOException {
        if (currentBlock == null || blockRowIndex >= currentBlock.getnRows()) {
            if (!readBlock()) {
                return false;
            }
        }

        currentBlock.fillRecord(blockRowIndex, record);
        blockRowIndex++;
        return true;
    }

    private boolean readBlock() throws IOException {
        int nColumns;
        try {
            nColumns = BinaryStreamReader.readVarInt(input);
        } catch (EOFException e) {
            endReached();
            return false;
        }
        int nRows = BinaryStreamReader.readVarInt(input);

        List names = new ArrayList<>(nColumns);
        List types = new ArrayList<>(nColumns);
        currentBlock = new Block(names, types, nRows);
        for (int i = 0; i < nColumns; i++) {
            ClickHouseColumn column = ClickHouseColumn.of(BinaryStreamReader.readString(input),
                    BinaryStreamReader.readString(input));
            names.add(column.getColumnName());
            types.add(column.getDataType().name());

            List values = new ArrayList<>(nRows);
            for (int j = 0; j < nRows; j++) {
                Object value = binaryStreamReader.readValue(column);
                values.add(value);
            }
            currentBlock.add(values);
        }
        blockRowIndex = 0;
        return true;
    }

    @Override
    public  T readValue(int colIndex) {
        return (T) currentRecord.get(getSchema().indexToName(colIndex));
    }

    @Override
    public  T readValue(String colName) {
        return (T) currentRecord.get(colName);
    }

    private static class Block {
        final List names;
        final List types;

        final List> values = new ArrayList<>();
        final int nRows;

        Block(List names, List types, int nRows) {
            this.names = names;
            this.types = types;
            this.nRows = nRows;
        }

        public void add(List values) {
            this.values.add(values);
        }

        public int getnRows() {
            return nRows;
        }

        private void fillRecord(int index, Map record) {
            int colIndex = 0;
            for (String name : names) {
                record.put(name, values.get(colIndex).get(index));
                colIndex++;
            }
        }
    }
}
    

    

    

            

    

            



    
    






    
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