1//-----------------------------------------------------------------------------
2// boost variant/detail/hash_variant.hpp header file
3// See http://www.boost.org for updates, documentation, and revision history.
4//-----------------------------------------------------------------------------
5//
6// Copyright (c) 2011-2023 Antony Polukhin
7//
8// Distributed under the Boost Software License, Version 1.0. (See
9// accompanying file LICENSE_1_0.txt or copy at
10// http://www.boost.org/LICENSE_1_0.txt)
11
12
13#ifndef BOOST_HASH_VARIANT_FUNCTION_HPP
14#define BOOST_HASH_VARIANT_FUNCTION_HPP
15
16#if defined(_MSC_VER)
17# pragma once
18#endif
19
20#include <boost/variant/variant_fwd.hpp>
21#include <boost/variant/static_visitor.hpp>
22#include <boost/variant/apply_visitor.hpp>
23#include <boost/functional/hash_fwd.hpp>
24
25namespace boost {
26
27 namespace detail { namespace variant {
28 struct variant_hasher: public boost::static_visitor<std::size_t> {
29 template <class T>
30 std::size_t operator()(T const& val) const {
31 boost::hash<T> hasher;
32 return hasher(val);
33 }
34 };
35 }}
36
37 template < BOOST_VARIANT_ENUM_PARAMS(typename T) >
38 std::size_t hash_value(variant< BOOST_VARIANT_ENUM_PARAMS(T) > const& val) {
39 std::size_t seed = boost::apply_visitor(detail::variant::variant_hasher(), val);
40 hash_combine(seed, val.which());
41 return seed;
42 }
43}
44
45#endif
46
47