Sprout/sprout/variant/hash.hpp
2016-02-25 18:48:28 +09:00

61 lines
1.7 KiB
C++

/*=============================================================================
Copyright (c) 2011-2016 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
#ifndef SPROUT_VARIANT_HASH_HPP
#define SPROUT_VARIANT_HASH_HPP
#include <functional>
#include <sprout/config.hpp>
#include <sprout/workaround/std/cstddef.hpp>
#include <sprout/functional/hash.hpp>
#include <sprout/variant/variant.hpp>
#include <sprout/variant/static_visitor.hpp>
#include <sprout/variant/apply_visitor.hpp>
namespace sprout {
namespace detail {
class variant_hash_visitor
: public sprout::static_visitor<std::size_t>
{
public:
template<typename T>
SPROUT_CONSTEXPR std::size_t operator()(T const& t) const {
return sprout::to_hash(t);
}
};
} // namespace detail
//
// hash_value
//
template<typename... Types>
inline SPROUT_CONSTEXPR std::size_t
hash_value(sprout::variant<Types...> const& v) {
return sprout::hash_combine(
sprout::apply_visitor(sprout::detail::variant_hash_visitor(), v),
v.which()
);
}
} // namespace sprout
namespace std {
#if defined(__clang__)
# pragma clang diagnostic push
# pragma clang diagnostic ignored "-Wmismatched-tags"
#endif
//
// hash
//
template<typename... Types>
struct hash<sprout::variant<Types...> >
: public sprout::hash<sprout::variant<Types...> >
{};
#if defined(__clang__)
# pragma clang diagnostic pop
#endif
} // namespace std
#endif // #ifndef SPROUT_VARIANT_HASH_HPP