ClickHouse/dbms/src/Functions/GatherUtils_createArraySource.cpp

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#include "GatherUtils.h"
namespace DB
{
/// Creates IArraySource from ColumnArray
template <typename... Types>
struct ArraySourceCreator;
template <typename Type, typename... Types>
struct ArraySourceCreator<Type, Types...>
{
static std::unique_ptr<IArraySource> create(const ColumnArray & col, const ColumnUInt8 * null_map, bool is_const, size_t total_rows)
{
if (typeid_cast<const ColumnVector<Type> *>(&col.getData()))
{
if (null_map)
{
if (is_const)
return std::make_unique<ConstSource<NullableArraySource<NumericArraySource<Type>>>>(col, *null_map, total_rows);
return std::make_unique<NullableArraySource<NumericArraySource<Type>>>(col, *null_map);
}
if (is_const)
return std::make_unique<ConstSource<NumericArraySource<Type>>>(col, total_rows);
return std::make_unique<NumericArraySource<Type>>(col);
}
return ArraySourceCreator<Types...>::create(col, null_map, is_const, total_rows);
}
};
template <>
struct ArraySourceCreator<>
{
static std::unique_ptr<IArraySource> create(const ColumnArray & col, const ColumnUInt8 * null_map, bool is_const, size_t total_rows)
{
if (null_map)
{
if (is_const)
return std::make_unique<ConstSource<NullableArraySource<GenericArraySource>>>(col, *null_map, total_rows);
return std::make_unique<NullableArraySource<GenericArraySource>>(col, *null_map);
}
if (is_const)
return std::make_unique<ConstSource<GenericArraySource>>(col, total_rows);
return std::make_unique<GenericArraySource>(col);
}
};
std::unique_ptr<IArraySource> createArraySource(const ColumnArray & col, bool is_const, size_t total_rows)
{
using Creator = typename ApplyTypeListForClass<ArraySourceCreator, TypeListNumbers>::Type;
if (auto column_nullable = typeid_cast<const ColumnNullable *>(&col.getData()))
{
auto column = ColumnArray::create(column_nullable->getNestedColumnPtr(), col.getOffsetsPtr());
return Creator::create(*column, &column_nullable->getNullMapColumn(), is_const, total_rows);
}
return Creator::create(col, nullptr, is_const, total_rows);
}
}