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#include <Columns/ColumnString.h>
#include <Columns/ColumnsNumber.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypeString.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionHelpers.h>
#include <Functions/IFunction.h>
#include <cstring>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_COLUMN;
extern const int TOO_LARGE_STRING_SIZE;
}
namespace
{
/// Prints whitespace n-times. Actually, space() could also be pushed down to repeat(). Chose a standalone-implementation because
/// we can do memset() whereas repeat() does memcpy().
class FunctionSpace : public IFunction
{
private:
static constexpr auto space = ' ';
/// Safety threshold against DoS.
static inline void checkRepeatTime(size_t repeat_time)
{
static constexpr auto max_repeat_times = 1'000'000uz;
if (repeat_time > max_repeat_times)
throw Exception(ErrorCodes::TOO_LARGE_STRING_SIZE, "Too many times to repeat ({}), maximum is: {}", repeat_time, max_repeat_times);
}
public:
static constexpr auto name = "space";
static FunctionPtr create(ContextPtr) { return std::make_shared<FunctionSpace>(); }
String getName() const override { return name; }
size_t getNumberOfArguments() const override { return 1; }
bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return true; }
DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
{
FunctionArgumentDescriptors args{
{"n", &isInteger<IDataType>, nullptr, "Integer"}
};
validateFunctionArgumentTypes(*this, arguments, args);
return std::make_shared<DataTypeString>();
}
template <typename DataType>
bool executeConstant(ColumnPtr col_times, ColumnString::Offsets & res_offsets, ColumnString::Chars & res_chars) const
{
const ColumnConst * col_times_const = checkAndGetColumn<ColumnConst>(col_times.get());
const ColumnPtr & col_times_const_internal = col_times_const->getDataColumnPtr();
if (!checkAndGetColumn<typename DataType::ColumnType>(col_times_const_internal.get()))
return false;
using T = typename DataType::FieldType;
T times = col_times_const->getValue<T>();
if (times < 1)
times = 0;
checkRepeatTime(times);
res_offsets.resize(col_times->size());
res_chars.resize(col_times->size() * (times + 1));
size_t pos = 0;
for (size_t i = 0; i < col_times->size(); ++i)
{
memset(res_chars.begin() + pos, space, times);
pos += times;
*(res_chars.begin() + pos) = '\0';
pos += 1;
res_offsets[i] = pos;
}
return true;
}
template <typename DataType>
bool executeVector(ColumnPtr col_times_, ColumnString::Offsets & res_offsets, ColumnString::Chars & res_chars) const
{
auto * col_times = checkAndGetColumn<typename DataType::ColumnType>(col_times_.get());
if (!col_times)
return false;
res_offsets.resize(col_times->size());
res_chars.resize(col_times->size() * 10); /// heuristic
const PaddedPODArray<typename DataType::FieldType> & times_data = col_times->getData();
size_t pos = 0;
for (size_t i = 0; i < col_times->size(); ++i)
{
typename DataType::FieldType times = times_data[i];
if (times < 1)
times = 0;
checkRepeatTime(times);
if (pos + times + 1 > res_chars.size())
res_chars.resize(std::max(2 * res_chars.size(), static_cast<size_t>(pos + times + 1)));
memset(res_chars.begin() + pos, space, times);
pos += times;
*(res_chars.begin() + pos) = '\0';
pos += 1;
res_offsets[i] = pos;
}
res_chars.resize(pos);
return true;
}
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t /*input_rows_count*/) const override
{
const auto & col_num = arguments[0].column;
auto col_res = ColumnString::create();
ColumnString::Offsets & res_offsets = col_res->getOffsets();
ColumnString::Chars & res_chars = col_res->getChars();
if (const ColumnConst * col_num_const = checkAndGetColumn<ColumnConst>(col_num.get()))
{
if ((executeConstant<DataTypeUInt8>(col_num, res_offsets, res_chars))
|| (executeConstant<DataTypeUInt16>(col_num, res_offsets, res_chars))
|| (executeConstant<DataTypeUInt32>(col_num, res_offsets, res_chars))
|| (executeConstant<DataTypeUInt64>(col_num, res_offsets, res_chars))
|| (executeConstant<DataTypeInt8>(col_num, res_offsets, res_chars))
|| (executeConstant<DataTypeInt16>(col_num, res_offsets, res_chars))
|| (executeConstant<DataTypeInt32>(col_num, res_offsets, res_chars))
|| (executeConstant<DataTypeInt64>(col_num, res_offsets, res_chars)))
return col_res;
}
else
{
if ((executeVector<DataTypeUInt8>(col_num, res_offsets, res_chars))
|| (executeVector<DataTypeUInt16>(col_num, res_offsets, res_chars))
|| (executeVector<DataTypeUInt32>(col_num, res_offsets, res_chars))
|| (executeVector<DataTypeUInt64>(col_num, res_offsets, res_chars))
|| (executeVector<DataTypeInt8>(col_num, res_offsets, res_chars))
|| (executeVector<DataTypeInt16>(col_num, res_offsets, res_chars))
|| (executeVector<DataTypeInt32>(col_num, res_offsets, res_chars))
|| (executeVector<DataTypeInt64>(col_num, res_offsets, res_chars)))
return col_res;
}
throw Exception(ErrorCodes::ILLEGAL_COLUMN, "Illegal column {} of argument of function {}", arguments[0].column->getName(), getName());
}
};
}
REGISTER_FUNCTION(Space)
{
factory.registerFunction<FunctionSpace>({}, FunctionFactory::CaseInsensitive);
}
}
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