Add h3kRing function

dbms/src/Functions/h3kRing.cpp

@@ -0,0 +1,103 @@
+#include "config_functions.h"
+#if USE_H3
+#    include <vector>
+#    include <Columns/ColumnArray.h>
+#    include <Columns/ColumnsNumber.h>
+#    include <DataTypes/DataTypeArray.h>
+#    include <DataTypes/DataTypesNumber.h>
+#    include <DataTypes/IDataType.h>
+#    include <Functions/FunctionFactory.h>
+#    include <Functions/IFunction.h>
+#    include <Common/typeid_cast.h>
+#    include <ext/range.h>
+
+extern "C" {
+#    ifdef __clang__
+#        pragma clang diagnostic push
+#        pragma clang diagnostic ignored "-Wdocumentation"
+#    endif
+
+#    include <h3api.h>
+
+#    ifdef __clang__
+#        pragma clang diagnostic pop
+#    endif
+}
+
+namespace DB
+{
+class FunctionH3KRing : public IFunction
+{
+public:
+    static constexpr auto name = "h3kRing";
+
+    static FunctionPtr create(const Context &) { return std::make_shared<FunctionH3KRing>(); }
+
+    std::string getName() const override { return name; }
+
+    size_t getNumberOfArguments() const override { return 2; }
+    bool useDefaultImplementationForConstants() const override { return true; }
+
+    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
+    {
+        auto arg = arguments[0].get();
+        if (!WhichDataType(arg).isUInt64())
+            throw Exception(
+                "Illegal type " + arg->getName() + " of argument " + std::to_string(1) + " of function " + getName() + ". Must be UInt64",
+                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
+
+        arg = arguments[1].get();
+        if (!isInteger(arg))
+            throw Exception(
+                "Illegal type " + arg->getName() + " of argument " + std::to_string(2) + " of function " + getName() + ". Must be integer",
+                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
+
+        return std::make_shared<DataTypeArray>(std::make_shared<DataTypeUInt64>());
+    }
+
+    void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t input_rows_count) override
+    {
+        const auto col_hindex = block.getByPosition(arguments[0]).column.get();
+        const auto col_k = block.getByPosition(arguments[1]).column.get();
+
+        auto dst = ColumnArray::create(ColumnUInt64::create());
+        auto & dst_data = dst->getData();
+        auto & dst_offsets = dst->getOffsets();
+        dst_offsets.resize(input_rows_count);
+        auto current_offset = 0;
+
+        std::vector<H3Index> hindex_vec;
+
+        for (const auto row : ext::range(0, input_rows_count))
+        {
+            const H3Index origin_hindex = col_hindex->getUInt(row);
+            const int k = col_k->getInt(row);
+
+            const auto vec_size = H3_EXPORT(maxKringSize)(k);
+            hindex_vec.resize(vec_size);
+            H3_EXPORT(kRing)(origin_hindex, k, hindex_vec.data());
+
+            dst_data.reserve(dst_data.size() + vec_size);
+            for (auto hindex : hindex_vec)
+            {
+                if (hindex != 0)
+                {
+                    current_offset++;
+                    dst_data.insert(hindex);
+                }
+            }
+            dst_offsets[row] = current_offset;
+        }
+
+        block.getByPosition(result).column = std::move(dst);
+    }
+};
+
+
+void registerFunctionH3KRing(FunctionFactory & factory)
+{
+    factory.registerFunction<FunctionH3KRing>();
+}
+
+}
+#endif

dbms/src/Functions/registerFunctionsGeo.cpp

@@ -16,6 +16,7 @@ void registerFunctionGeohashesInBox(FunctionFactory & factory);
 void registerFunctionGeoToH3(FunctionFactory &);
 void registerFunctionH3GetResolution(FunctionFactory &);
 void registerFunctionH3IsValid(FunctionFactory &);
+void registerFunctionH3KRing(FunctionFactory &);
 #endif
 
 void registerFunctionsGeo(FunctionFactory & factory)
@@ -31,6 +32,7 @@ void registerFunctionsGeo(FunctionFactory & factory)
     registerFunctionGeoToH3(factory);
 	registerFunctionH3GetResolution(factory);
 	registerFunctionH3IsValid(factory);
+	registerFunctionH3KRing(factory);
 #endif
 }
 

dbms/tests/queries/0_stateless/01042_h3_k_ring.reference

@@ -0,0 +1,3 @@
+[581250224954015743,581259021047037951,581267817140060159,581276613233082367,581500913605148671,581518505791193087,581764796395814911]
+[581276613233082367]
+[581276613233082367]

dbms/tests/queries/0_stateless/01042_h3_k_ring.sql

@@ -0,0 +1,3 @@
+SELECT arraySort(h3kRing(581276613233082367, 1));
+SELECT h3kRing(581276613233082367, 0);
+SELECT h3kRing(581276613233082367, -1);