ClickHouse/src/Functions/polygonsDistance.cpp

#include <Functions/FunctionFactory.h>
#include <Functions/geometryConverters.h>

#include <boost/geometry.hpp>
#include <boost/geometry/geometries/point_xy.hpp>
#include <boost/geometry/geometries/polygon.hpp>

#include <common/logger_useful.h>

#include <Columns/ColumnArray.h>
#include <Columns/ColumnTuple.h>
#include <Columns/ColumnConst.h>
#include <Columns/ColumnsNumber.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypeArray.h>
#include <DataTypes/DataTypeTuple.h>
#include <DataTypes/DataTypeCustomGeo.h>

#include <memory>
#include <utility>

namespace DB
{

template <typename Point>
class FunctionPolygonsDistance : public IFunction
{
public:
    static inline const char * name;

    explicit FunctionPolygonsDistance() = default;

    static FunctionPtr create(const Context &)
    {
        return std::make_shared<FunctionPolygonsDistance>();
    }

    String getName() const override
    {
        return name;
    }

    bool isVariadic() const override
    {
        return false;
    }

    size_t getNumberOfArguments() const override
    {
        return 2;
    }

    DataTypePtr getReturnTypeImpl(const DataTypes &) const override
    {
        return std::make_shared<DataTypeFloat64>();
    }

    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & /*result_type*/, size_t input_rows_count) const override
    {
        auto first_parser = getConverterBasedOnType<Point>(arguments[0]);
        auto second_parser = getConverterBasedOnType<Point>(arguments[1]);     

        auto first = parseFigure(first_parser);
        auto second = parseFigure(second_parser);

        auto res_column = ColumnFloat64::create();
        auto & res_data = res_column->getData();
        res_data.reserve(input_rows_count);

        for (size_t i = 0; i < input_rows_count; i++)
        {
            boost::geometry::correct(first[i]);
            boost::geometry::correct(second[i]);

            res_data.emplace_back(boost::geometry::distance(first[i], second[i]));
        }

        return res_column;
    }

    bool useDefaultImplementationForConstants() const override
    {
        return true;
    }
};

template <>
const char * FunctionPolygonsDistance<CartesianPoint>::name = "polygonsDistanceCartesian";

template <>
const char * FunctionPolygonsDistance<GeographicPoint>::name = "polygonsDistanceGeographic";


void registerFunctionPolygonsDistance(FunctionFactory & factory)
{
    factory.registerFunction<FunctionPolygonsDistance<CartesianPoint>>();
    factory.registerFunction<FunctionPolygonsDistance<GeographicPoint>>();
}


}