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119 lines
4.0 KiB
C++
119 lines
4.0 KiB
C++
#include <Columns/ColumnString.h>
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#include <Columns/ColumnArray.h>
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#include <Columns/ColumnConst.h>
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#include <DataTypes/DataTypeArray.h>
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#include <DataTypes/DataTypeString.h>
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#include <Functions/FunctionFactory.h>
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#include <Functions/FunctionHelpers.h>
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#include <Functions/Regexps.h>
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#include <memory>
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#include <string>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int BAD_ARGUMENTS;
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}
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namespace
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{
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/** Match all groups of given input string with given re, return array of arrays of matches.
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*
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* SELECT extractGroups('hello abc=111 world', '("[^"]+"|\\w+)=("[^"]+"|\\w+)')
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* should produce:
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* ['abc', '111']
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*/
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class FunctionExtractGroups : public IFunction
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{
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public:
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static constexpr auto name = "extractGroups";
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static FunctionPtr create(ContextPtr) { return std::make_shared<FunctionExtractGroups>(); }
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String getName() const override { return name; }
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size_t getNumberOfArguments() const override { return 2; }
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bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return true; }
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bool useDefaultImplementationForConstants() const override { return false; }
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ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return {1}; }
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DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
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{
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FunctionArgumentDescriptors args{
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{"haystack", &isStringOrFixedString<IDataType>, nullptr, "const String or const FixedString"},
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{"needle", &isStringOrFixedString<IDataType>, isColumnConst, "const String or const FixedString"},
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};
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validateFunctionArgumentTypes(*this, arguments, args);
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return std::make_shared<DataTypeArray>(std::make_shared<DataTypeString>());
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}
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ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t input_rows_count) const override
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{
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const ColumnPtr column_haystack = arguments[0].column;
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const ColumnPtr column_needle = arguments[1].column;
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const auto needle = typeid_cast<const ColumnConst &>(*column_needle).getValue<String>();
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if (needle.empty())
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throw Exception(ErrorCodes::BAD_ARGUMENTS, "{} length of 'needle' argument must be greater than 0.", getName());
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const Regexps::Regexp regexp = Regexps::createRegexp<false, false, false>(needle);
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const auto & re2 = regexp.getRE2();
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if (!re2)
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throw Exception(ErrorCodes::BAD_ARGUMENTS, "There are no groups in regexp: {}", needle);
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const size_t groups_count = re2->NumberOfCapturingGroups();
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if (!groups_count)
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throw Exception(ErrorCodes::BAD_ARGUMENTS, "There are no groups in regexp: {}", needle);
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// Including 0-group, which is the whole regexp.
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PODArrayWithStackMemory<std::string_view, 128> matched_groups(groups_count + 1);
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ColumnArray::ColumnOffsets::MutablePtr offsets_col = ColumnArray::ColumnOffsets::create();
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ColumnString::MutablePtr data_col = ColumnString::create();
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auto & offsets_data = offsets_col->getData();
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offsets_data.resize(input_rows_count);
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ColumnArray::Offset current_offset = 0;
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for (size_t i = 0; i < input_rows_count; ++i)
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{
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std::string_view current_row = column_haystack->getDataAt(i).toView();
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if (re2->Match({current_row.data(), current_row.size()},
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0, current_row.size(), re2_st::RE2::UNANCHORED, matched_groups.data(),
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static_cast<int>(matched_groups.size())))
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{
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// 1 is to exclude group #0 which is whole re match.
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for (size_t group = 1; group <= groups_count; ++group)
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data_col->insertData(matched_groups[group].data(), matched_groups[group].size());
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current_offset += groups_count;
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}
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offsets_data[i] = current_offset;
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}
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return ColumnArray::create(std::move(data_col), std::move(offsets_col));
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}
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};
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}
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REGISTER_FUNCTION(ExtractGroups)
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{
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factory.registerFunction<FunctionExtractGroups>();
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}
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}
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