Add levenshtein and hamming_distance functions

be/src/exprs/function/function_hamming_distance.cpp

@@ -0,0 +1,320 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include <algorithm>
+#include <vector>
+
+#include "common/status.h"
+#include "core/column/column_nullable.h"
+#include "core/column/column_string.h"
+#include "core/data_type/data_type_number.h"
+#include "core/string_ref.h"
+#include "exprs/function/simple_function_factory.h"
+#include "util/simd/vstring_function.h"
+
+namespace doris {
+
+class FunctionHammingDistance : public IFunction {
+public:
+ using ResultDataType = DataTypeInt64;
+ using ResultPaddedPODArray = PaddedPODArray<Int64>;
+ using ResultColumnType = ColumnVector<ResultDataType::PType>;
+
+ static constexpr auto name = "hamming_distance";
+
+ static FunctionPtr create() { return std::make_shared<FunctionHammingDistance>(); }
+
+ String get_name() const override { return name; }
+ size_t get_number_of_arguments() const override { return 2; }
+
+ DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {
+ const bool has_nullable = std::ranges::any_of(
+ arguments, [](const DataTypePtr& type) { return type->is_nullable(); });
+ if (has_nullable) {
+ return make_nullable(std::make_shared<ResultDataType>());
+ }
+ return std::make_shared<ResultDataType>();
+ }
+
+ bool use_default_implementation_for_nulls() const override { return false; }
+
+ Status execute_impl(FunctionContext* /*context*/, Block& block, const ColumnNumbers& arguments,
+ uint32_t result, size_t input_rows_count) const override {
+ const auto& [left_col, left_const] =
+ unpack_if_const(block.get_by_position(arguments[0]).column);
+ const auto& [right_col, right_const] =
+ unpack_if_const(block.get_by_position(arguments[1]).column);
+
+ const auto* left_nullable = check_and_get_column<ColumnNullable>(left_col.get());
+ const auto* right_nullable = check_and_get_column<ColumnNullable>(right_col.get());
+
+ const IColumn* left_nested =
+ left_nullable ? &left_nullable->get_nested_column() : left_col.get();
+ const IColumn* right_nested =
+ right_nullable ? &right_nullable->get_nested_column() : right_col.get();
+
+ const auto* left_str_col = assert_cast<const ColumnString*>(left_nested);
+ const auto* right_str_col = assert_cast<const ColumnString*>(right_nested);
+
+ auto res_col = ResultColumnType::create(input_rows_count);
+ auto& res_data = res_col->get_data();
+
+ const NullMap* left_null_map =
+ left_nullable ? &left_nullable->get_null_map_data() : nullptr;
+ const NullMap* right_null_map =
+ right_nullable ? &right_nullable->get_null_map_data() : nullptr;
+ const bool has_nullable = left_null_map != nullptr || right_null_map != nullptr;
+
+ if (!has_nullable) {
+ if (left_const) {
+ RETURN_IF_ERROR(scalar_vector(left_str_col->get_data_at(0).trim_tail_padding_zero(),
+ *right_str_col, res_data));
+ } else if (right_const) {
+ RETURN_IF_ERROR(vector_scalar(
+ *left_str_col, right_str_col->get_data_at(0).trim_tail_padding_zero(),
+ res_data));
+ } else {
+ RETURN_IF_ERROR(vector_vector(*left_str_col, *right_str_col, res_data));
+ }
+ block.replace_by_position(result, std::move(res_col));
+ return Status::OK();
+ }
+
+ auto null_col = ColumnUInt8::create(input_rows_count, 0);
+ auto& null_map = null_col->get_data();
+ if (left_const) {
+ if (left_null_map && (*left_null_map)[0]) {
+ std::fill(null_map.begin(), null_map.end(), 1);
+ block.replace_by_position(
+ result, ColumnNullable::create(std::move(res_col), std::move(null_col)));
+ return Status::OK();
+ }
+
+ const auto left = left_str_col->get_data_at(0).trim_tail_padding_zero();
+ RETURN_IF_ERROR(scalar_vector_nullable(left, *right_str_col, right_null_map, res_data,
+ null_map));
+ } else if (right_const) {
+ if (right_null_map && (*right_null_map)[0]) {
+ std::fill(null_map.begin(), null_map.end(), 1);
+ block.replace_by_position(
+ result, ColumnNullable::create(std::move(res_col), std::move(null_col)));
+ return Status::OK();
+ }
+
+ RETURN_IF_ERROR(vector_scalar_nullable(
+ *left_str_col, right_str_col->get_data_at(0).trim_tail_padding_zero(),
+ left_null_map, res_data, null_map));
+ } else {
+ for (size_t i = 0; i < input_rows_count; ++i) {
+ const bool left_is_null = left_null_map && (*left_null_map)[i];
+ const bool right_is_null = right_null_map && (*right_null_map)[i];
+ if (left_is_null || right_is_null) {
+ null_map[i] = 1;
+ res_data[i] = 0;
+ continue;
+ }
+
+ RETURN_IF_ERROR(hamming_distance(
+ left_str_col->get_data_at(i).trim_tail_padding_zero(),
+ right_str_col->get_data_at(i).trim_tail_padding_zero(), res_data[i], i));
+ }
+ }
+
+ block.replace_by_position(result,
+ ColumnNullable::create(std::move(res_col), std::move(null_col)));
+ return Status::OK();
+ }
+
+private:
+ static Status vector_vector(const ColumnString& lcol, const ColumnString& rcol,
+ ResultPaddedPODArray& res) {
+ DCHECK_EQ(lcol.size(), rcol.size());
+
+ const size_t size = lcol.size();
+ res.resize(size);
+ std::vector<size_t> left_offsets;
+ std::vector<size_t> right_offsets;
+ for (size_t i = 0; i < size; ++i) {
+ const auto left = lcol.get_data_at(i).trim_tail_padding_zero();
+ const auto right = rcol.get_data_at(i).trim_tail_padding_zero();
+ RETURN_IF_ERROR(hamming_distance_with_offsets(
+ left, left_offsets, false, simd::VStringFunctions::is_ascii(left), right,
+ right_offsets, false, simd::VStringFunctions::is_ascii(right), res[i], i));
+ }
+ return Status::OK();
+ }
+
+ static Status vector_scalar(const ColumnString& lcol, const StringRef& rdata,
+ ResultPaddedPODArray& res) {
+ const size_t size = lcol.size();
+ res.resize(size);
+ const bool right_ascii = simd::VStringFunctions::is_ascii(rdata);
+ std::vector<size_t> right_offsets;
+ simd::VStringFunctions::get_utf8_char_offsets(rdata, right_offsets);
+ std::vector<size_t> left_offsets;
+ for (size_t i = 0; i < size; ++i) {
+ const auto left = lcol.get_data_at(i).trim_tail_padding_zero();
+ RETURN_IF_ERROR(hamming_distance_with_offsets(
+ left, left_offsets, false, simd::VStringFunctions::is_ascii(left), rdata,
+ right_offsets, true, right_ascii, res[i], i));
+ }
+ return Status::OK();
+ }
+
+ static Status scalar_vector(const StringRef& ldata, const ColumnString& rcol,
+ ResultPaddedPODArray& res) {
+ const size_t size = rcol.size();
+ res.resize(size);
+ const bool left_ascii = simd::VStringFunctions::is_ascii(ldata);
+ std::vector<size_t> left_offsets;
+ simd::VStringFunctions::get_utf8_char_offsets(ldata, left_offsets);
+ std::vector<size_t> right_offsets;
+ for (size_t i = 0; i < size; ++i) {
+ const auto right = rcol.get_data_at(i).trim_tail_padding_zero();
+ RETURN_IF_ERROR(hamming_distance_with_offsets(
+ ldata, left_offsets, true, left_ascii, right, right_offsets, false,
+ simd::VStringFunctions::is_ascii(right), res[i], i));
+ }
+ return Status::OK();
+ }
+
+ static Status vector_scalar_nullable(const ColumnString& lcol, const StringRef& rdata,
+ const NullMap* left_null_map, ResultPaddedPODArray& res,
+ NullMap& null_map) {
+ const size_t size = lcol.size();
+ res.resize(size);
+ const bool right_ascii = simd::VStringFunctions::is_ascii(rdata);
+ std::vector<size_t> right_offsets;
+ simd::VStringFunctions::get_utf8_char_offsets(rdata, right_offsets);
+ std::vector<size_t> left_offsets;
+ for (size_t i = 0; i < size; ++i) {
+ if (left_null_map && (*left_null_map)[i]) {
+ null_map[i] = 1;
+ res[i] = 0;
+ continue;
+ }
+
+ const auto left = lcol.get_data_at(i).trim_tail_padding_zero();
+ RETURN_IF_ERROR(hamming_distance_with_offsets(
+ left, left_offsets, false, simd::VStringFunctions::is_ascii(left), rdata,
+ right_offsets, true, right_ascii, res[i], i));
+ }
+ return Status::OK();
+ }
+
+ static Status scalar_vector_nullable(const StringRef& ldata, const ColumnString& rcol,
+ const NullMap* right_null_map, ResultPaddedPODArray& res,
+ NullMap& null_map) {
+ const size_t size = rcol.size();
+ res.resize(size);
+ const bool left_ascii = simd::VStringFunctions::is_ascii(ldata);
+ std::vector<size_t> left_offsets;
+ simd::VStringFunctions::get_utf8_char_offsets(ldata, left_offsets);
+ std::vector<size_t> right_offsets;
+ for (size_t i = 0; i < size; ++i) {
+ if (right_null_map && (*right_null_map)[i]) {
+ null_map[i] = 1;
+ res[i] = 0;
+ continue;
+ }
+
+ const auto right = rcol.get_data_at(i).trim_tail_padding_zero();
+ RETURN_IF_ERROR(hamming_distance_with_offsets(
+ ldata, left_offsets, true, left_ascii, right, right_offsets, false,
+ simd::VStringFunctions::is_ascii(right), res[i], i));
+ }
+ return Status::OK();
+ }
+
+ static Status hamming_distance_ascii(const StringRef& left, const StringRef& right,
+ Int64& result, size_t row) {
+ if (left.size != right.size) {
+ return Status::InvalidArgument(
+ "hamming_distance requires strings of the same length at row {}", row);
+ }
+
+ Int64 distance = 0;
+ for (size_t i = 0; i < left.size; ++i) {
+ distance += static_cast<Int64>(left.data[i] != right.data[i]);
+ }
+ result = distance;
+ return Status::OK();
+ }
+
+ static Status hamming_distance_utf8(const StringRef& left,
+ const std::vector<size_t>& left_offsets,
+ const StringRef& right,
+ const std::vector<size_t>& right_offsets, Int64& result,
+ size_t row) {
+ if (left_offsets.size() != right_offsets.size()) {
+ return Status::InvalidArgument(
+ "hamming_distance requires strings of the same length at row {}", row);
+ }
+
+ Int64 distance = 0;
+ const size_t len = left_offsets.size();
+ for (size_t i = 0; i + 1 < len; ++i) {
+ const size_t left_off = left_offsets[i];
+ const size_t left_next = left_offsets[i + 1];
+ const size_t right_off = right_offsets[i];
+ const size_t right_next = right_offsets[i + 1];
+ distance += static_cast<Int64>(!simd::VStringFunctions::utf8_char_equal(
+ left, left_off, left_next, right, right_off, right_next));
+ }
+ if (len > 0) {
+ const size_t left_off = left_offsets[len - 1];
+ const size_t right_off = right_offsets[len - 1];
+ distance += static_cast<Int64>(!simd::VStringFunctions::utf8_char_equal(
+ left, left_off, left.size, right, right_off, right.size));
+ }
+
+ result = distance;
+ return Status::OK();
+ }
+
+ static Status hamming_distance_with_offsets(
+ const StringRef& left, std::vector<size_t>& left_offsets, bool left_offsets_ready,
+ bool left_ascii, const StringRef& right, std::vector<size_t>& right_offsets,
+ bool right_offsets_ready, bool right_ascii, Int64& result, size_t row) {
+ if (left_ascii && right_ascii) {
+ return hamming_distance_ascii(left, right, result, row);
+ }
+
+ if (!left_offsets_ready) {
+ simd::VStringFunctions::get_utf8_char_offsets(left, left_offsets);
+ }
+ if (!right_offsets_ready) {
+ simd::VStringFunctions::get_utf8_char_offsets(right, right_offsets);
+ }
+ return hamming_distance_utf8(left, left_offsets, right, right_offsets, result, row);
+ }
+
+ static Status hamming_distance(const StringRef& left, const StringRef& right, Int64& result,
+ size_t row) {
+ std::vector<size_t> left_offsets;
+ std::vector<size_t> right_offsets;
+ return hamming_distance_with_offsets(
+ left, left_offsets, false, simd::VStringFunctions::is_ascii(left), right,
+ right_offsets, false, simd::VStringFunctions::is_ascii(right), result, row);
+ }
+};
+
+void register_function_hamming_distance(SimpleFunctionFactory& factory) {
+ factory.register_function<FunctionHammingDistance>();
+}
+
+} // namespace doris