ClickHouse/src/Functions/h3ToString.cpp
2021-08-09 18:01:08 +03:00

98 lines
2.6 KiB
C++

#if !defined(ARCADIA_BUILD)
# include "config_functions.h"
#endif
#if USE_H3
#include <Columns/ColumnString.h>
#include <DataTypes/DataTypeString.h>
#include <Functions/FunctionFactory.h>
#include <Functions/IFunction.h>
#include <Common/typeid_cast.h>
#include <h3api.h>
#define H3_INDEX_STRING_LENGTH 17 // includes \0 terminator
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
namespace
{
class FunctionH3ToString : public IFunction
{
public:
static constexpr auto name = "h3ToString";
static FunctionPtr create(ContextPtr) { return std::make_shared<FunctionH3ToString>(); }
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 UInt64",
arg->getName(), 1, getName());
return std::make_shared<DataTypeString>();
}
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t input_rows_count) const override
{
const auto * col_hindex = arguments[0].column.get();
auto col_res = ColumnString::create();
auto & vec_res = col_res->getChars();
auto & vec_offsets = col_res->getOffsets();
vec_offsets.resize(input_rows_count);
vec_res.resize_fill(input_rows_count * H3_INDEX_STRING_LENGTH, '\0');
char * begin = reinterpret_cast<char *>(vec_res.data());
char * pos = begin;
for (size_t i = 0; i < input_rows_count; ++i)
{
const UInt64 hindex = col_hindex->getUInt(i);
if (!isValidCell(hindex))
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT, "Invalid H3 index: {}", hindex);
h3ToString(hindex, pos, H3_INDEX_STRING_LENGTH);
// move to end of the index
while (*pos != '\0')
pos++;
vec_offsets[i] = ++pos - begin;
}
vec_res.resize(pos - begin);
return col_res;
}
};
}
void registerFunctionH3ToString(FunctionFactory & factory)
{
factory.registerFunction<FunctionH3ToString>();
}
}
#endif