ClickHouse/libs/libcommon/include/ext/make_array_n.hpp

#pragma once

#include <utility>
#include <type_traits>
#include <array>

namespace ext
{

	namespace detail
	{

		template<std::size_t size, typename T, std::size_t... indexes>
		constexpr auto make_array_n_impl(T && value, std::index_sequence<indexes...>)
		{
			return std::array<std::decay_t<T>, size>{ (static_cast<void>(indexes), value)..., std::forward<T>(value) };
		}

	}

	template<typename T>
	constexpr auto make_array_n(std::integral_constant<std::size_t, 0>, T &&)
	{
		return std::array<std::decay_t<T>, 0>{};
	}

	template<std::size_t size, typename T>
	constexpr auto make_array_n(std::integral_constant<std::size_t, size>, T && value)
	{
		return detail::make_array_n_impl<size>(std::forward<T>(value), std::make_index_sequence<size - 1>{});
	}

	template<std::size_t size, typename T>
	constexpr auto make_array_n(T && value)
	{
		return make_array_n(std::integral_constant<std::size_t, size>{}, std::forward<T>(value));
	}
}