ClickHouse/src/Functions/FunctionsStringSearchToString.h
2020-11-17 16:24:45 +03:00

88 lines
3.0 KiB
C++

#pragma once
#include <Columns/ColumnArray.h>
#include <Columns/ColumnConst.h>
#include <Columns/ColumnString.h>
#include <Columns/ColumnFixedString.h>
#include <Columns/ColumnVector.h>
#include <DataTypes/DataTypeArray.h>
#include <DataTypes/DataTypeString.h>
#include <DataTypes/DataTypesNumber.h>
#include <Functions/FunctionHelpers.h>
#include <Functions/IFunctionImpl.h>
#include <IO/WriteHelpers.h>
#include <Interpreters/Context.h>
#include <common/StringRef.h>
namespace DB
{
/** Applies regexp re2 and extracts:
* - the first subpattern, if the regexp has a subpattern;
* - the zero subpattern (the match part, otherwise);
* - if not match - an empty string.
* extract(haystack, pattern)
*/
namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
extern const int ILLEGAL_COLUMN;
}
template <typename Impl, typename Name>
class FunctionsStringSearchToString : public IFunction
{
public:
static constexpr auto name = Name::name;
static FunctionPtr create(const Context &) { return std::make_shared<FunctionsStringSearchToString>(); }
String getName() const override { return name; }
size_t getNumberOfArguments() const override { return 2; }
bool useDefaultImplementationForConstants() const override { return true; }
ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return {1}; }
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
if (!isString(arguments[0]))
throw Exception(
"Illegal type " + arguments[0]->getName() + " of argument of function " + getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
if (!isString(arguments[1]))
throw Exception(
"Illegal type " + arguments[1]->getName() + " of argument of function " + getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return std::make_shared<DataTypeString>();
}
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t /*input_rows_count*/) const override
{
const ColumnPtr column = arguments[0].column;
const ColumnPtr column_needle = arguments[1].column;
const ColumnConst * col_needle = typeid_cast<const ColumnConst *>(&*column_needle);
if (!col_needle)
throw Exception("Second argument of function " + getName() + " must be constant string", ErrorCodes::ILLEGAL_COLUMN);
if (const ColumnString * col = checkAndGetColumn<ColumnString>(column.get()))
{
auto col_res = ColumnString::create();
ColumnString::Chars & vec_res = col_res->getChars();
ColumnString::Offsets & offsets_res = col_res->getOffsets();
Impl::vector(col->getChars(), col->getOffsets(), col_needle->getValue<String>(), vec_res, offsets_res);
return col_res;
}
else
throw Exception(
"Illegal column " + arguments[0].column->getName() + " of argument of function " + getName(),
ErrorCodes::ILLEGAL_COLUMN);
}
};
}