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/*!
@file
Defines `boost::hana::zip_shortest_with`.
@copyright Louis Dionne 2013-2017
Distributed under the Boost Software License, Version 1.0.
(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
*/
#ifndef BOOST_HANA_ZIP_SHORTEST_WITH_HPP
#define BOOST_HANA_ZIP_SHORTEST_WITH_HPP
#include <boost/hana/fwd/zip_shortest_with.hpp>
#include <boost/hana/concept/sequence.hpp>
#include <boost/hana/core/dispatch.hpp>
#include <boost/hana/config.hpp>
#include <boost/hana/detail/algorithm.hpp>
#include <boost/hana/detail/fast_and.hpp>
#include <boost/hana/integral_constant.hpp>
#include <boost/hana/length.hpp>
#include <boost/hana/take_front.hpp>
#include <boost/hana/zip_with.hpp>
#include <cstddef>
BOOST_HANA_NAMESPACE_BEGIN
//! @cond
template <typename F, typename Xs, typename ...Ys>
constexpr auto
zip_shortest_with_t::operator()(F&& f, Xs&& xs, Ys&& ...ys) const {
#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
static_assert(detail::fast_and<
hana::Sequence<Xs>::value, hana::Sequence<Ys>::value...
>::value,
"hana::zip_shortest_with(f, xs, ys...) requires 'xs' and 'ys...' to be Sequences");
#endif
return zip_shortest_with_impl<typename hana::tag_of<Xs>::type>::apply(
static_cast<F&&>(f),
static_cast<Xs&&>(xs),
static_cast<Ys&&>(ys)...
);
}
//! @endcond
template <typename S, bool condition>
struct zip_shortest_with_impl<S, when<condition>> : default_ {
template <typename F, typename ...Xs>
static constexpr decltype(auto) apply(F&& f, Xs&& ...xs) {
constexpr std::size_t lengths[] = {
decltype(hana::length(xs))::value...
};
constexpr std::size_t min_len =
*detail::min_element(lengths, lengths + sizeof...(xs));
return hana::zip_with(static_cast<F&&>(f),
hana::take_front(static_cast<Xs&&>(xs), hana::size_c<min_len>)...
);
}
};
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_ZIP_SHORTEST_WITH_HPP
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