ClickHouse/dbms/src/Functions/h3ToString.cpp

87 lines
2.6 KiB
C++
Raw Normal View History

#include "config_functions.h"
#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
{
2020-02-25 18:10:48 +00:00
namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
class FunctionH3ToString : public IFunction
{
public:
static constexpr auto name = "h3ToString";
static FunctionPtr create(const Context &) { 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; }
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
auto arg = arguments[0].get();
if (!WhichDataType(arg).isUInt64())
throw Exception(
"Illegal type " + arg->getName() + " of argument " + std::to_string(1) + " of function " + getName() + ". Must be UInt64",
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return std::make_shared<DataTypeString>();
}
void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t input_rows_count) override
{
const auto col_hindex = block.getByPosition(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 (!h3IsValid(hindex))
{
throw Exception("Invalid H3 index: " + std::to_string(hindex), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
}
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);
block.getByPosition(result).column = std::move(col_res);
}
};
void registerFunctionH3ToString(FunctionFactory & factory)
{
factory.registerFunction<FunctionH3ToString>();
}
}
#endif