ClickHouse/src/Functions/lengthUTF8.cpp
Li Yin 4088c0a7f3 Automated function registration
Automated register all functions with below naming convention by
iterating through the symbols:
void DB::registerXXX(DB::FunctionFactory &)
2022-07-29 15:39:50 +08:00

81 lines
2.4 KiB
C++

#include <DataTypes/DataTypeString.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionStringOrArrayToT.h>
#include <Common/UTF8Helpers.h>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
namespace
{
/** If the string is UTF-8 encoded text, it returns the length of the text in code points.
* (not in characters: the length of the text "ё" can be either 1 or 2, depending on the normalization)
* (not in characters: the length of the text "" can be either 1 or 2, depending on the normalization)
* Otherwise, the behavior is undefined.
*/
struct LengthUTF8Impl
{
static constexpr auto is_fixed_to_constant = false;
static void vector(const ColumnString::Chars & data, const ColumnString::Offsets & offsets, PaddedPODArray<UInt64> & res)
{
size_t size = offsets.size();
ColumnString::Offset prev_offset = 0;
for (size_t i = 0; i < size; ++i)
{
res[i] = UTF8::countCodePoints(&data[prev_offset], offsets[i] - prev_offset - 1);
prev_offset = offsets[i];
}
}
static void vectorFixedToConstant(const ColumnString::Chars & /*data*/, size_t /*n*/, UInt64 & /*res*/)
{
}
static void vectorFixedToVector(const ColumnString::Chars & data, size_t n, PaddedPODArray<UInt64> & res)
{
size_t size = data.size() / n;
for (size_t i = 0; i < size; ++i)
{
res[i] = UTF8::countCodePoints(&data[i * n], n);
}
}
[[noreturn]] static void array(const ColumnString::Offsets &, PaddedPODArray<UInt64> &)
{
throw Exception("Cannot apply function lengthUTF8 to Array argument", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
}
[[noreturn]] static void uuid(const ColumnUUID::Container &, size_t &, PaddedPODArray<UInt64> &)
{
throw Exception("Cannot apply function lengthUTF8 to UUID argument", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
}
};
struct NameLengthUTF8
{
static constexpr auto name = "lengthUTF8";
};
using FunctionLengthUTF8 = FunctionStringOrArrayToT<LengthUTF8Impl, NameLengthUTF8, UInt64>;
}
REGISTER_FUNCTION(LengthUTF8)
{
factory.registerFunction<FunctionLengthUTF8>();
/// Compatibility aliases.
factory.registerFunction<FunctionLengthUTF8>("CHAR_LENGTH", FunctionFactory::CaseInsensitive);
factory.registerFunction<FunctionLengthUTF8>("CHARACTER_LENGTH", FunctionFactory::CaseInsensitive);
}
}