ClickHouse/src/Functions/regexpQuoteMeta.cpp
Nikolai Kochetov 384718e6c3 Part 8.
2020-10-19 18:27:41 +03:00

119 lines
3.5 KiB
C++

#include <Columns/ColumnString.h>
#include <DataTypes/DataTypeString.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionHelpers.h>
#include <common/find_symbols.h>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_COLUMN;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
namespace
{
class FunctionRegexpQuoteMeta : public IFunction
{
public:
static constexpr auto name = "regexpQuoteMeta";
static FunctionPtr create(const Context &)
{
return std::make_shared<FunctionRegexpQuoteMeta>();
}
String getName() const override
{
return name;
}
size_t getNumberOfArguments() const override
{
return 1;
}
bool useDefaultImplementationForConstants() const override
{
return true;
}
DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
{
if (!WhichDataType(arguments[0].type).isString())
throw Exception(
"Illegal type " + arguments[0].type->getName() + " of 1 argument of function " + getName() + ". Must be String.",
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return std::make_shared<DataTypeString>();
}
ColumnPtr executeImpl(ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t input_rows_count) const override
{
const ColumnPtr & column_string = arguments[0].column;
const ColumnString * input = checkAndGetColumn<ColumnString>(column_string.get());
if (!input)
throw Exception(
"Illegal column " + arguments[0].column->getName() + " of first argument of function " + getName(),
ErrorCodes::ILLEGAL_COLUMN);
auto dst_column = ColumnString::create();
auto & dst_data = dst_column->getChars();
auto & dst_offsets = dst_column->getOffsets();
dst_offsets.resize(input_rows_count);
const ColumnString::Offsets & src_offsets = input->getOffsets();
const auto * src_begin = reinterpret_cast<const char *>(input->getChars().data());
const auto * src_pos = src_begin;
for (size_t row_idx = 0; row_idx < input_rows_count; ++row_idx)
{
/// NOTE This implementation slightly differs from re2::RE2::QuoteMeta.
/// It escapes zero byte as \0 instead of \x00
/// and it escapes only required characters.
/// This is Ok. Look at comments in re2.cc
const char * src_end = src_begin + src_offsets[row_idx] - 1;
while (true)
{
const char * next_src_pos = find_first_symbols<'\0', '\\', '|', '(', ')', '^', '$', '.', '[', ']', '?', '*', '+', '{', ':', '-'>(src_pos, src_end);
size_t bytes_to_copy = next_src_pos - src_pos;
size_t old_dst_size = dst_data.size();
dst_data.resize(old_dst_size + bytes_to_copy);
memcpySmallAllowReadWriteOverflow15(dst_data.data() + old_dst_size, src_pos, bytes_to_copy);
src_pos = next_src_pos + 1;
if (next_src_pos == src_end)
{
dst_data.emplace_back('\0');
break;
}
dst_data.emplace_back('\\');
dst_data.emplace_back(*next_src_pos);
}
dst_offsets[row_idx] = dst_data.size();
}
return dst_column;
}
};
}
void registerFunctionRegexpQuoteMeta(FunctionFactory & factory)
{
factory.registerFunction<FunctionRegexpQuoteMeta>();
}
}