/
splitByRegexp.cpp
158 lines (127 loc) · 3.99 KB
/
splitByRegexp.cpp
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#include <Columns/ColumnConst.h>
#include <Functions/FunctionHelpers.h>
#include <Functions/FunctionTokens.h>
#include <Functions/FunctionFactory.h>
#include <Functions/Regexps.h>
#include <Common/StringUtils/StringUtils.h>
#include <Common/assert_cast.h>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_COLUMN;
}
/** Functions that split strings into an array of strings or vice versa.
*
* splitByRegexp(regexp, s[, max_substrings])
*/
namespace
{
using Pos = const char *;
class SplitByRegexpImpl
{
private:
Regexps::RegexpPtr re;
OptimizedRegularExpression::MatchVec matches;
Pos pos;
Pos end;
std::optional<size_t> max_splits;
size_t splits;
bool max_substrings_includes_remaining_string;
public:
static constexpr auto name = "splitByRegexp";
static bool isVariadic() { return true; }
static size_t getNumberOfArguments() { return 0; }
static ColumnNumbers getArgumentsThatAreAlwaysConstant() { return {0, 2}; }
static void checkArguments(const IFunction & func, const ColumnsWithTypeAndName & arguments)
{
checkArgumentsWithSeparatorAndOptionalMaxSubstrings(func, arguments);
}
static constexpr auto strings_argument_position = 1uz;
void init(const ColumnsWithTypeAndName & arguments, bool max_substrings_includes_remaining_string_)
{
const ColumnConst * col = checkAndGetColumnConstStringOrFixedString(arguments[0].column.get());
if (!col)
throw Exception(ErrorCodes::ILLEGAL_COLUMN, "Illegal column {} of first argument of function {}. "
"Must be constant string.", arguments[0].column->getName(), name);
if (!col->getValue<String>().empty())
re = std::make_shared<OptimizedRegularExpression>(Regexps::createRegexp<false, false, false>(col->getValue<String>()));
max_substrings_includes_remaining_string = max_substrings_includes_remaining_string_;
max_splits = extractMaxSplits(arguments, 2);
}
/// Called for each next string.
void set(Pos pos_, Pos end_)
{
pos = pos_;
end = end_;
splits = 0;
}
/// Get the next token, if any, or return false.
bool get(Pos & token_begin, Pos & token_end)
{
if (!re)
{
if (pos == end)
return false;
token_begin = pos;
if (max_splits)
{
if (max_substrings_includes_remaining_string)
{
if (splits == *max_splits - 1)
{
token_end = end;
pos = end;
return true;
}
}
else
if (splits == *max_splits)
return false;
}
pos += 1;
token_end = pos;
++splits;
}
else
{
if (!pos || pos > end)
return false;
token_begin = pos;
if (max_splits)
{
if (max_substrings_includes_remaining_string)
{
if (splits == *max_splits - 1)
{
token_end = end;
pos = nullptr;
return true;
}
}
else
if (splits == *max_splits)
return false;
}
if (!re->match(pos, end - pos, matches) || !matches[0].length)
{
token_end = end;
pos = end + 1;
}
else
{
token_end = pos + matches[0].offset;
pos = token_end + matches[0].length;
++splits;
}
}
return true;
}
};
using FunctionSplitByRegexp = FunctionTokens<SplitByRegexpImpl>;
}
REGISTER_FUNCTION(SplitByRegexp)
{
factory.registerFunction<FunctionSplitByRegexp>();
}
}