1/* Copyright 2003-2022 Joaquin M Lopez Munoz.
2 * Distributed under the Boost Software License, Version 1.0.
3 * (See accompanying file LICENSE_1_0.txt or copy at
4 * http://www.boost.org/LICENSE_1_0.txt)
5 *
6 * See http://www.boost.org/libs/multi_index for library home page.
7 */
8
9#ifndef BOOST_MULTI_INDEX_DETAIL_HASH_INDEX_ARGS_HPP
10#define BOOST_MULTI_INDEX_DETAIL_HASH_INDEX_ARGS_HPP
11
12#if defined(_MSC_VER)
13#pragma once
14#endif
15
16#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
17#include <boost/container_hash/hash.hpp>
18#include <boost/mpl/aux_/na.hpp>
19#include <boost/mpl/eval_if.hpp>
20#include <boost/mpl/identity.hpp>
21#include <boost/mpl/if.hpp>
22#include <boost/multi_index/tag.hpp>
23#include <boost/static_assert.hpp>
24#include <boost/type_traits/is_same.hpp>
25#include <functional>
26
27namespace boost{
28
29namespace multi_index{
30
31namespace detail{
32
33/* Hashed index specifiers can be instantiated in two forms:
34 *
35 * (hashed_unique|hashed_non_unique)<
36 * KeyFromValue,
37 * Hash=boost::hash<KeyFromValue::result_type>,
38 * Pred=std::equal_to<KeyFromValue::result_type> >
39 * (hashed_unique|hashed_non_unique)<
40 * TagList,
41 * KeyFromValue,
42 * Hash=boost::hash<KeyFromValue::result_type>,
43 * Pred=std::equal_to<KeyFromValue::result_type> >
44 *
45 * hashed_index_args implements the machinery to accept this
46 * argument-dependent polymorphism.
47 */
48
49template<typename KeyFromValue>
50struct index_args_default_hash
51{
52 typedef ::boost::hash<typename KeyFromValue::result_type> type;
53};
54
55template<typename KeyFromValue>
56struct index_args_default_pred
57{
58 typedef std::equal_to<typename KeyFromValue::result_type> type;
59};
60
61template<typename Arg1,typename Arg2,typename Arg3,typename Arg4>
62struct hashed_index_args
63{
64 typedef is_tag<Arg1> full_form;
65
66 typedef typename mpl::if_<
67 full_form,
68 Arg1,
69 tag< > >::type tag_list_type;
70 typedef typename mpl::if_<
71 full_form,
72 Arg2,
73 Arg1>::type key_from_value_type;
74 typedef typename mpl::if_<
75 full_form,
76 Arg3,
77 Arg2>::type supplied_hash_type;
78 typedef typename mpl::eval_if<
79 mpl::is_na<supplied_hash_type>,
80 index_args_default_hash<key_from_value_type>,
81 mpl::identity<supplied_hash_type>
82 >::type hash_type;
83 typedef typename mpl::if_<
84 full_form,
85 Arg4,
86 Arg3>::type supplied_pred_type;
87 typedef typename mpl::eval_if<
88 mpl::is_na<supplied_pred_type>,
89 index_args_default_pred<key_from_value_type>,
90 mpl::identity<supplied_pred_type>
91 >::type pred_type;
92
93 BOOST_STATIC_ASSERT(is_tag<tag_list_type>::value);
94 BOOST_STATIC_ASSERT(!mpl::is_na<key_from_value_type>::value);
95 BOOST_STATIC_ASSERT(!mpl::is_na<hash_type>::value);
96 BOOST_STATIC_ASSERT(!mpl::is_na<pred_type>::value);
97};
98
99} /* namespace multi_index::detail */
100
101} /* namespace multi_index */
102
103} /* namespace boost */
104
105#endif
106