ClickHouse/src/Functions/s2GetNeighbors.cpp
2021-08-10 14:31:15 +03:00

114 lines
2.8 KiB
C++

#if !defined(ARCADIA_BUILD)
# include "config_functions.h"
#endif
#if USE_S2_GEOMETRY
#include <Columns/ColumnArray.h>
#include <Columns/ColumnsNumber.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypeArray.h>
#include <Functions/FunctionFactory.h>
#include <Common/typeid_cast.h>
#include <common/range.h>
#include "s2_fwd.h"
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
extern const int BAD_ARGUMENTS;
}
namespace
{
/**
* Each cell in s2 library is a quadrilateral bounded by four geodesics.
* So, each cell has 4 neighbors
*/
class FunctionS2GetNeighbors : public IFunction
{
public:
static constexpr auto name = "s2GetNeighbors";
static FunctionPtr create(ContextPtr)
{
return std::make_shared<FunctionS2GetNeighbors>();
}
std::string getName() const override
{
return name;
}
size_t getNumberOfArguments() const override { return 1; }
bool useDefaultImplementationForConstants() const override { return true; }
bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return true; }
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
const auto * arg = arguments[0].get();
if (!WhichDataType(arg).isUInt64())
throw Exception(
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
"Illegal type {} of argument {} of function {}. Must be Float64",
arg->getName(), 1, getName());
return std::make_shared<DataTypeArray>(std::make_shared<DataTypeUInt64>());
}
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t input_rows_count) const override
{
const auto * col_id = arguments[0].column.get();
auto dst = ColumnArray::create(ColumnUInt64::create());
auto & dst_data = dst->getData();
auto & dst_offsets = dst->getOffsets();
dst_offsets.resize(input_rows_count);
size_t current_offset = 0;
for (const auto row : collections::range(0, input_rows_count))
{
const UInt64 id = col_id->getUInt(row);
S2CellId cell_id(id);
if (!cell_id.is_valid())
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Cell is not valid");
S2CellId neighbors[4];
cell_id.GetEdgeNeighbors(neighbors);
dst_data.reserve(dst_data.size() + 4);
for (auto & neighbor : neighbors)
{
++current_offset;
dst_data.insert(neighbor.id());
}
dst_offsets[row] = current_offset;
}
return dst;
}
};
}
void registerFunctionS2GetNeighbors(FunctionFactory & factory)
{
factory.registerFunction<FunctionS2GetNeighbors>();
}
}
#endif