Method executeImpl

src/Functions/array/arrayShuffle.cpp:111–143

template <typename Traits>
ColumnPtr FunctionArrayShuffleImpl<Traits>::executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t) const
{
    auto col = arguments[0].column->convertToFullColumnIfConst();
    const ColumnArray * array = checkAndGetColumn<ColumnArray>(col.get());
    if (!array)
        throw Exception(
            ErrorCodes::ILLEGAL_COLUMN, "Illegal column {} of first argument of function {}", arguments[0].column->getName(), getName());

    const auto seed = [&]() -> uint64_t
    {
        // If present, seed comes as the last argument
        if (arguments.size() != Traits::max_num_params)
            return randomSeed();
        const auto * val = arguments[Traits::seed_param_idx].column.get();
        return val->getUInt(0);
    }();
    pcg64_fast rng(seed);

    size_t limit = [&]() -> size_t
    {
        if constexpr (Traits::has_limit)
        {
            if (arguments.size() > 1)
            {
                const auto * val = arguments[1].column.get();
                return val->getUInt(0);
            }
        }
        return 0;
    }();

    return executeGeneric(*array, rng, limit);
}

template <typename Traits>
ColumnPtr FunctionArrayShuffleImpl<Traits>::executeGeneric(const ColumnArray & array, pcg64_fast & rng, size_t limit [[maybe_unused]])