aboutsummaryrefslogtreecommitdiff
path: root/paludis/util/hashes.hh
blob: e700f23f67f8aa773fa5cf49a5d759a0bc8aad1a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
/* vim: set sw=4 sts=4 et foldmethod=syntax : */

/*
 * Copyright (c) 2008, 2010, 2011 Ciaran McCreesh
 *
 * This file is part of the Paludis package manager. Paludis is free software;
 * you can redistribute it and/or modify it under the terms of the GNU General
 * Public License version 2, as published by the Free Software Foundation.
 *
 * Paludis is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef PALUDIS_GUARD_PALUDIS_UTIL_HASHES_HH
#define PALUDIS_GUARD_PALUDIS_UTIL_HASHES_HH 1

#include <paludis/util/attributes.hh>
#include <paludis/util/wrapped_value-fwd.hh>
#include <paludis/util/fs_path-fwd.hh>
#include <cstddef>
#include <tuple>
#include <utility>
#include <string>
#include <type_traits>
#include <memory>

namespace paludis
{
    namespace hash_internals
    {
        template <typename T_, bool is_numeric_>
        struct DefaultHash
        {
            static std::size_t hash(const T_ & t)
            {
                return static_cast<std::size_t>(t);
            }
        };

        template <typename T_>
        struct DefaultHash<T_, false>
        {
            static std::size_t hash(const T_ & t)
            {
                return t.hash();
            }
        };
    }

    template <typename T_>
    class Hash
    {
        public:
            std::size_t operator() (const T_ & t) const
            {
                return hash_internals::DefaultHash<T_, std::is_integral<T_>::value || std::is_enum<T_>::value>::hash(t);
            }
    };

    template <>
    struct PALUDIS_VISIBLE Hash<std::string>
    {
        std::size_t operator() (const std::string &) const PALUDIS_ATTRIBUTE((warn_unused_result));
    };

    template <>
    struct PALUDIS_VISIBLE Hash<FSPath>
    {
        std::size_t operator() (const FSPath &) const PALUDIS_ATTRIBUTE((warn_unused_result));
    };

    template <typename T_, typename U_>
    struct Hash<std::pair<T_, U_> >
    {
        std::size_t operator() (const std::pair<T_, U_> & p) const
        {
            return Hash<T_>()(p.first) ^ Hash<U_>()(p.second);
        }
    };

    template <unsigned n_, typename... Keys_>
    std::size_t single_tuple_hash(const std::tuple<Keys_...> & p)
    {
        return Hash<typename std::tuple_element<n_, std::tuple<Keys_...> >::type>()(std::get<n_>(p));
    }

    struct FinishedHashingTuple
    {
    };

    struct NotFinishedHashingTuple
    {
    };

    template <unsigned n_, typename... Keys_>
    std::size_t accumulate_tuple_hash(const std::tuple<Keys_...> &, std::size_t v, const FinishedHashingTuple &)
    {
        return v;
    }

    template <unsigned n_, typename... Keys_>
    std::size_t accumulate_tuple_hash(const std::tuple<Keys_...> & p, std::size_t v, const NotFinishedHashingTuple &)
    {
        return accumulate_tuple_hash<n_ + 1, Keys_...>(p, (v << 8) ^ single_tuple_hash<n_>(p),
                typename std::conditional<std::tuple_size<std::tuple<Keys_...> >::value == n_ + 1,
                    FinishedHashingTuple, NotFinishedHashingTuple>::type());
    }

    template <typename... Keys_>
    struct Hash<std::tuple<Keys_...> >
    {
        std::size_t operator() (const std::tuple<Keys_...> & p) const
        {
            return accumulate_tuple_hash<0, Keys_...>(p, 0, NotFinishedHashingTuple());
        }
    };

    template <typename Tag_>
    struct Hash<WrappedValue<Tag_> >
    {
        std::size_t operator() (const WrappedValue<Tag_> & v) const
        {
            return Hash<typename WrappedValueTraits<Tag_>::UnderlyingType>()(v.value());
        }
    };

    template <typename T_>
    struct Hash<const T_>
    {
        std::size_t operator() (const T_ & t) const
        {
            return Hash<T_>()(t);
        }
    };

    template <typename T_>
    struct Hash<T_ &>
    {
        std::size_t operator() (const T_ & t) const
        {
            return Hash<T_>()(t);
        }
    };

    template <typename T_>
    struct Hash<T_ *>
    {
        std::size_t operator() (const T_ * const t) const
        {
            return Hash<T_>(*t);
        }
    };

    template <typename T_>
    struct Hash<std::shared_ptr<T_> >
    {
        std::size_t operator() (const std::shared_ptr<const T_> & t) const
        {
            return Hash<T_>()(*t);
        }
    };
}

#endif