Add h3getResolution function

dbms/src/Functions/h3GetResolution.cpp

@@ -0,0 +1,77 @@
+#include "config_functions.h"
+#if USE_H3
+#    include <Columns/ColumnsNumber.h>
+#    include <DataTypes/DataTypesNumber.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 FunctionH3GetResolution : public IFunction
+{
+public:
+    static constexpr auto name = "h3GetResolution";
+
+    static FunctionPtr create(const Context &) { return std::make_shared<FunctionH3GetResolution>(); }
+
+    std::string getName() const override { return name; }
+
+    size_t getNumberOfArguments() const override { return 1; }
+    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);
+
+        return std::make_shared<DataTypeUInt8>();
+    }
+
+    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();
+
+        auto dst = ColumnVector<UInt8>::create();
+        auto & dst_data = dst->getData();
+        dst_data.resize(input_rows_count);
+
+        for (const auto row : ext::range(0, input_rows_count))
+        {
+            const UInt64 hindex = col_hindex->getUInt(row);
+
+            UInt8 res = H3_EXPORT(h3GetResolution)(hindex);
+
+            dst_data[row] = res;
+        }
+
+        block.getByPosition(result).column = std::move(dst);
+    }
+};
+
+
+void registerFunctionH3GetResolution(FunctionFactory & factory)
+{
+    factory.registerFunction<FunctionH3GetResolution>();
+}
+
+}
+#endif

dbms/src/Functions/registerFunctionsGeo.cpp

@@ -14,6 +14,7 @@ void registerFunctionGeohashesInBox(FunctionFactory & factory);
 
 #if USE_H3
 void registerFunctionGeoToH3(FunctionFactory &);
+void registerFunctionH3GetResolution(FunctionFactory &);
 #endif
 
 void registerFunctionsGeo(FunctionFactory & factory)
@@ -27,6 +28,7 @@ void registerFunctionsGeo(FunctionFactory & factory)
 
 #if USE_H3
     registerFunctionGeoToH3(factory);
+	registerFunctionH3GetResolution(factory);
 #endif
 }
 

dbms/tests/queries/0_stateless/01040_h3_get_resolution.reference

@@ -0,0 +1,3 @@
+1
+10
+15

dbms/tests/queries/0_stateless/01040_h3_get_resolution.sql

@@ -0,0 +1,3 @@
+SELECT h3GetResolution(581276613233082367);
+SELECT h3GetResolution(621807531097128959);
+SELECT h3GetResolution(644325529233966508);