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c17b0a1c | 1 | // TR1 functional_hash.h header -*- C++ -*- |
e9a9931d | 2 | |
f1717362 | 3 | // Copyright (C) 2007-2016 Free Software Foundation, Inc. |
e9a9931d | 4 | // |
5 | // This file is part of the GNU ISO C++ Library. This library is free | |
6 | // software; you can redistribute it and/or modify it under the | |
7 | // terms of the GNU General Public License as published by the | |
6bc9506f | 8 | // Free Software Foundation; either version 3, or (at your option) |
e9a9931d | 9 | // any later version. |
10 | ||
11 | // This library is distributed in the hope that it will be useful, | |
12 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | // GNU General Public License for more details. | |
15 | ||
6bc9506f | 16 | // Under Section 7 of GPL version 3, you are granted additional |
17 | // permissions described in the GCC Runtime Library Exception, version | |
18 | // 3.1, as published by the Free Software Foundation. | |
19 | ||
20 | // You should have received a copy of the GNU General Public License and | |
21 | // a copy of the GCC Runtime Library Exception along with this program; | |
22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 | // <http://www.gnu.org/licenses/>. | |
e9a9931d | 24 | |
25 | /** @file tr1/functional_hash.h | |
26 | * This is an internal header file, included by other library headers. | |
5846aeac | 27 | * Do not attempt to use it directly. @headername{tr1/functional} |
e9a9931d | 28 | */ |
29 | ||
c17b0a1c | 30 | #ifndef _GLIBCXX_TR1_FUNCTIONAL_HASH_H |
31 | #define _GLIBCXX_TR1_FUNCTIONAL_HASH_H 1 | |
e9a9931d | 32 | |
c17b0a1c | 33 | #pragma GCC system_header |
e9a9931d | 34 | |
2948dd21 | 35 | namespace std _GLIBCXX_VISIBILITY(default) |
95757e52 | 36 | { |
37 | namespace tr1 | |
38 | { | |
2948dd21 | 39 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
40 | ||
95757e52 | 41 | /// Class template hash. |
42 | // Declaration of default hash functor std::tr1::hash. The types for | |
43 | // which std::tr1::hash<T> is well-defined is in clause 6.3.3. of the PDTR. | |
44 | template<typename _Tp> | |
45 | struct hash : public std::unary_function<_Tp, size_t> | |
46 | { | |
47 | size_t | |
48 | operator()(_Tp __val) const; | |
49 | }; | |
50 | ||
51 | /// Partial specializations for pointer types. | |
52 | template<typename _Tp> | |
53 | struct hash<_Tp*> : public std::unary_function<_Tp*, size_t> | |
54 | { | |
55 | size_t | |
56 | operator()(_Tp* __p) const | |
57 | { return reinterpret_cast<size_t>(__p); } | |
58 | }; | |
59 | ||
60 | /// Explicit specializations for integer types. | |
61 | #define _TR1_hashtable_define_trivial_hash(_Tp) \ | |
62 | template<> \ | |
63 | inline size_t \ | |
64 | hash<_Tp>::operator()(_Tp __val) const \ | |
65 | { return static_cast<size_t>(__val); } | |
66 | ||
67 | _TR1_hashtable_define_trivial_hash(bool); | |
68 | _TR1_hashtable_define_trivial_hash(char); | |
69 | _TR1_hashtable_define_trivial_hash(signed char); | |
70 | _TR1_hashtable_define_trivial_hash(unsigned char); | |
71 | _TR1_hashtable_define_trivial_hash(wchar_t); | |
72 | _TR1_hashtable_define_trivial_hash(short); | |
73 | _TR1_hashtable_define_trivial_hash(int); | |
74 | _TR1_hashtable_define_trivial_hash(long); | |
75 | _TR1_hashtable_define_trivial_hash(long long); | |
76 | _TR1_hashtable_define_trivial_hash(unsigned short); | |
77 | _TR1_hashtable_define_trivial_hash(unsigned int); | |
78 | _TR1_hashtable_define_trivial_hash(unsigned long); | |
79 | _TR1_hashtable_define_trivial_hash(unsigned long long); | |
80 | ||
81 | #undef _TR1_hashtable_define_trivial_hash | |
82 | ||
83 | // Fowler / Noll / Vo (FNV) Hash (type FNV-1a) | |
84 | // (Used by the next specializations of std::tr1::hash.) | |
85 | ||
86 | /// Dummy generic implementation (for sizeof(size_t) != 4, 8). | |
3103d73c | 87 | template<size_t> |
88 | struct _Fnv_hash_base | |
95757e52 | 89 | { |
5d279b6d | 90 | template<typename _Tp> |
91 | static size_t | |
92 | hash(const _Tp* __ptr, size_t __clength) | |
93 | { | |
94 | size_t __result = 0; | |
95 | const char* __cptr = reinterpret_cast<const char*>(__ptr); | |
96 | for (; __clength; --__clength) | |
97 | __result = (__result * 131) + *__cptr++; | |
98 | return __result; | |
99 | } | |
95757e52 | 100 | }; |
101 | ||
102 | template<> | |
3103d73c | 103 | struct _Fnv_hash_base<4> |
95757e52 | 104 | { |
5d279b6d | 105 | template<typename _Tp> |
106 | static size_t | |
107 | hash(const _Tp* __ptr, size_t __clength) | |
108 | { | |
109 | size_t __result = static_cast<size_t>(2166136261UL); | |
110 | const char* __cptr = reinterpret_cast<const char*>(__ptr); | |
111 | for (; __clength; --__clength) | |
112 | { | |
113 | __result ^= static_cast<size_t>(*__cptr++); | |
114 | __result *= static_cast<size_t>(16777619UL); | |
115 | } | |
116 | return __result; | |
117 | } | |
95757e52 | 118 | }; |
119 | ||
120 | template<> | |
3103d73c | 121 | struct _Fnv_hash_base<8> |
95757e52 | 122 | { |
5d279b6d | 123 | template<typename _Tp> |
124 | static size_t | |
125 | hash(const _Tp* __ptr, size_t __clength) | |
126 | { | |
127 | size_t __result | |
128 | = static_cast<size_t>(14695981039346656037ULL); | |
129 | const char* __cptr = reinterpret_cast<const char*>(__ptr); | |
130 | for (; __clength; --__clength) | |
131 | { | |
132 | __result ^= static_cast<size_t>(*__cptr++); | |
133 | __result *= static_cast<size_t>(1099511628211ULL); | |
134 | } | |
135 | return __result; | |
136 | } | |
95757e52 | 137 | }; |
138 | ||
3103d73c | 139 | struct _Fnv_hash |
140 | : public _Fnv_hash_base<sizeof(size_t)> | |
141 | { | |
142 | using _Fnv_hash_base<sizeof(size_t)>::hash; | |
143 | ||
144 | template<typename _Tp> | |
145 | static size_t | |
146 | hash(const _Tp& __val) | |
5d279b6d | 147 | { return hash(&__val, sizeof(__val)); } |
3103d73c | 148 | }; |
149 | ||
95757e52 | 150 | /// Explicit specializations for float. |
151 | template<> | |
152 | inline size_t | |
153 | hash<float>::operator()(float __val) const | |
154 | { | |
95757e52 | 155 | // 0 and -0 both hash to zero. |
3103d73c | 156 | return __val != 0.0f ? std::tr1::_Fnv_hash::hash(__val) : 0; |
2c63b18a | 157 | } |
95757e52 | 158 | |
159 | /// Explicit specializations for double. | |
160 | template<> | |
161 | inline size_t | |
162 | hash<double>::operator()(double __val) const | |
163 | { | |
3103d73c | 164 | // 0 and -0 both hash to zero. |
165 | return __val != 0.0 ? std::tr1::_Fnv_hash::hash(__val) : 0; | |
2c63b18a | 166 | } |
95757e52 | 167 | |
168 | /// Explicit specializations for long double. | |
169 | template<> | |
170 | _GLIBCXX_PURE size_t | |
171 | hash<long double>::operator()(long double __val) const; | |
172 | ||
173 | /// Explicit specialization of member operator for non-builtin types. | |
174 | template<> | |
175 | _GLIBCXX_PURE size_t | |
176 | hash<string>::operator()(string) const; | |
177 | ||
178 | template<> | |
179 | _GLIBCXX_PURE size_t | |
180 | hash<const string&>::operator()(const string&) const; | |
181 | ||
182 | #ifdef _GLIBCXX_USE_WCHAR_T | |
183 | template<> | |
184 | _GLIBCXX_PURE size_t | |
185 | hash<wstring>::operator()(wstring) const; | |
e9a9931d | 186 | |
95757e52 | 187 | template<> |
188 | _GLIBCXX_PURE size_t | |
189 | hash<const wstring&>::operator()(const wstring&) const; | |
e9a9931d | 190 | #endif |
2948dd21 | 191 | |
192 | _GLIBCXX_END_NAMESPACE_VERSION | |
95757e52 | 193 | } |
194 | } | |
c17b0a1c | 195 | |
196 | #endif // _GLIBCXX_TR1_FUNCTIONAL_HASH_H |