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HashFunctions.h
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1// -*- mode: c++; c-basic-offset: 4 -*-
2/*
3 * Copyright (C) 2005, 2006, 2008 Apple Inc. All rights reserved.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
14 *
15 * You should have received a copy of the GNU Library General Public License
16 * along with this library; see the file COPYING.LIB. If not, write to
17 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
18 * Boston, MA 02110-1301, USA.
19 *
20 */
21
22#ifndef WTF_HashFunctions_h
23#define WTF_HashFunctions_h
24
25#include "RefPtr.h"
26#include <kjs/global.h>
27#ifdef HAVE_STDINT_H
28#include <stdint.h>
29#endif
30
31namespace WTF {
32
33 template<size_t size> struct IntTypes;
34 template<> struct IntTypes<1> { typedef int8_t SignedType; typedef uint8_t UnsignedType; };
35 template<> struct IntTypes<2> { typedef int16_t SignedType; typedef uint16_t UnsignedType; };
36 template<> struct IntTypes<4> { typedef int32_t SignedType; typedef uint32_t UnsignedType; };
37 template<> struct IntTypes<8> { typedef int64_t SignedType; typedef uint64_t UnsignedType; };
38
39 // integer hash function
40
41 // Thomas Wang's 32 Bit Mix Function: http://www.cris.com/~Ttwang/tech/inthash.htm
42 inline unsigned intHash(uint8_t key8)
43 {
44 unsigned key = key8;
45 key += ~(key << 15);
46 key ^= (key >> 10);
47 key += (key << 3);
48 key ^= (key >> 6);
49 key += ~(key << 11);
50 key ^= (key >> 16);
51 return key;
52 }
53
54 // Thomas Wang's 32 Bit Mix Function: http://www.cris.com/~Ttwang/tech/inthash.htm
55 inline unsigned intHash(uint16_t key16)
56 {
57 unsigned key = key16;
58 key += ~(key << 15);
59 key ^= (key >> 10);
60 key += (key << 3);
61 key ^= (key >> 6);
62 key += ~(key << 11);
63 key ^= (key >> 16);
64 return key;
65 }
66
67 // Thomas Wang's 32 Bit Mix Function: http://www.cris.com/~Ttwang/tech/inthash.htm
68 inline unsigned intHash(uint32_t key)
69 {
70 key += ~(key << 15);
71 key ^= (key >> 10);
72 key += (key << 3);
73 key ^= (key >> 6);
74 key += ~(key << 11);
75 key ^= (key >> 16);
76 return key;
77 }
78
79 // Thomas Wang's 64 bit Mix Function: http://www.cris.com/~Ttwang/tech/inthash.htm
80 inline unsigned intHash(uint64_t key)
81 {
82 key += ~(key << 32);
83 key ^= (key >> 22);
84 key += ~(key << 13);
85 key ^= (key >> 8);
86 key += (key << 3);
87 key ^= (key >> 15);
88 key += ~(key << 27);
89 key ^= (key >> 31);
90 return static_cast<unsigned>(key);
91 }
92
93 template<typename T> struct IntHash {
94 static unsigned hash(T key) { return intHash(static_cast<typename IntTypes<sizeof(T)>::UnsignedType>(key)); }
95 static bool equal(T a, T b) { return a == b; }
96 static const bool safeToCompareToEmptyOrDeleted = true;
97 };
98
99 template<typename T> struct FloatHash {
100 static unsigned hash(T key) { return intHash(*reinterpret_cast<typename IntTypes<sizeof(T)>::UnsignedType*>(&key)); }
101 static bool equal(T a, T b) { return a == b; }
102 static const bool safeToCompareToEmptyOrDeleted = true;
103 };
104
105 // pointer identity hash function
106
107 template<typename T> struct PtrHash {
108 static unsigned hash(T key)
109 {
110#if COMPILER(MSVC)
111#pragma warning(push)
112#pragma warning(disable: 4244) // work around what seems to be a bug in MSVC's conversion warnings
113#endif
114 return IntHash<uintptr_t>::hash(reinterpret_cast<uintptr_t>(key));
115#if COMPILER(MSVC)
116#pragma warning(pop)
117#endif
118 }
119 static bool equal(T a, T b) { return a == b; }
120 static const bool safeToCompareToEmptyOrDeleted = true;
121 };
122 template<typename P> struct PtrHash<RefPtr<P> > : PtrHash<P*> {
123 using PtrHash<P*>::hash;
124 static unsigned hash(const RefPtr<P>& key) { return hash(key.get()); }
125 using PtrHash<P*>::equal;
126 static bool equal(const RefPtr<P>& a, const RefPtr<P>& b) { return a == b; }
127 static bool equal(P* a, const RefPtr<P>& b) { return a == b; }
128 static bool equal(const RefPtr<P>& a, P* b) { return a == b; }
129 };
130
131 // default hash function for each type
132
133 template<typename T> struct DefaultHash;
134
135 template<typename T, typename U> struct PairHash {
136 static unsigned hash(const std::pair<T, U>& p)
137 {
138 return intHash((static_cast<uint64_t>(DefaultHash<T>::Hash::hash(p.first)) << 32 | DefaultHash<U>::Hash::hash(p.second)));
139 }
140 static bool equal(const std::pair<T, U>& a, const std::pair<T, U>& b)
141 {
142 return DefaultHash<T>::Hash::equal(a.first, b.first) && DefaultHash<U>::Hash::equal(a.second, b.second);
143 }
144 static const bool safeToCompareToEmptyOrDeleted = DefaultHash<T>::Hash::safeToCompareToEmptyOrDeleted
145 && DefaultHash<U>::Hash::safeToCompareToEmptyOrDeleted;
146 };
147
148 // make IntHash the default hash function for many integer types
149
150 template<> struct DefaultHash<short> { typedef IntHash<unsigned> Hash; };
151 template<> struct DefaultHash<unsigned short> { typedef IntHash<unsigned> Hash; };
152 template<> struct DefaultHash<int> { typedef IntHash<unsigned> Hash; };
153 template<> struct DefaultHash<unsigned> { typedef IntHash<unsigned> Hash; };
154 template<> struct DefaultHash<long> { typedef IntHash<unsigned long> Hash; };
155 template<> struct DefaultHash<unsigned long> { typedef IntHash<unsigned long> Hash; };
156 template<> struct DefaultHash<long long> { typedef IntHash<unsigned long long> Hash; };
157 template<> struct DefaultHash<unsigned long long> { typedef IntHash<unsigned long long> Hash; };
158
159#if !COMPILER(MSVC) || defined(_NATIVE_WCHAR_T_DEFINED)
160 template<> struct DefaultHash<wchar_t> { typedef IntHash<wchar_t> Hash; };
161#endif
162
163 template<> struct DefaultHash<float> { typedef FloatHash<float> Hash; };
164 template<> struct DefaultHash<double> { typedef FloatHash<double> Hash; };
165
166 // make PtrHash the default hash function for pointer types that don't specialize
167
168 template<typename P> struct DefaultHash<P*> { typedef PtrHash<P*> Hash; };
169 template<typename P> struct DefaultHash<RefPtr<P> > { typedef PtrHash<RefPtr<P> > Hash; };
170
171 template<typename T, typename U> struct DefaultHash<std::pair<T, U> > { typedef PairHash<T, U> Hash; };
172
173} // namespace WTF
174
175using WTF::DefaultHash;
176using WTF::IntHash;
177using WTF::PtrHash;
178
179#endif // WTF_HashFunctions_h
RefPtr.h
WTF::RefPtr
Definition: RefPtr.h:37
WTF::RefPtr::get
T * get() const
Definition: RefPtr.h:56
int
WTF
Definition: ASCIICType.h:45
WTF::intHash
unsigned intHash(uint8_t key8)
Definition: HashFunctions.h:42
WTF::DefaultHash< P * >::Hash
PtrHash< P * > Hash
Definition: HashFunctions.h:168
WTF::DefaultHash< RefPtr< P > >::Hash
PtrHash< RefPtr< P > > Hash
Definition: HashFunctions.h:169
WTF::DefaultHash< double >::Hash
FloatHash< double > Hash
Definition: HashFunctions.h:164
WTF::DefaultHash< float >::Hash
FloatHash< float > Hash
Definition: HashFunctions.h:163
WTF::DefaultHash< int >::Hash
IntHash< unsigned > Hash
Definition: HashFunctions.h:152
WTF::DefaultHash< long >::Hash
IntHash< unsigned long > Hash
Definition: HashFunctions.h:154
WTF::DefaultHash< long long >::Hash
IntHash< unsigned long long > Hash
Definition: HashFunctions.h:156
WTF::DefaultHash< short >::Hash
IntHash< unsigned > Hash
Definition: HashFunctions.h:150
WTF::DefaultHash< std::pair< T, U > >::Hash
PairHash< T, U > Hash
Definition: HashFunctions.h:171
WTF::DefaultHash< unsigned >::Hash
IntHash< unsigned > Hash
Definition: HashFunctions.h:153
WTF::DefaultHash< unsigned long >::Hash
IntHash< unsigned long > Hash
Definition: HashFunctions.h:155
WTF::DefaultHash< unsigned long long >::Hash
IntHash< unsigned long long > Hash
Definition: HashFunctions.h:157
WTF::DefaultHash< unsigned short >::Hash
IntHash< unsigned > Hash
Definition: HashFunctions.h:151
WTF::DefaultHash< wchar_t >::Hash
IntHash< wchar_t > Hash
Definition: HashFunctions.h:160
WTF::DefaultHash
Definition: HashFunctions.h:133
WTF::FloatHash
Definition: HashFunctions.h:99
WTF::FloatHash::hash
static unsigned hash(T key)
Definition: HashFunctions.h:100
WTF::FloatHash::equal
static bool equal(T a, T b)
Definition: HashFunctions.h:101
WTF::FloatHash::safeToCompareToEmptyOrDeleted
static const bool safeToCompareToEmptyOrDeleted
Definition: HashFunctions.h:102
WTF::IntHash
Definition: HashFunctions.h:93
WTF::IntHash::equal
static bool equal(T a, T b)
Definition: HashFunctions.h:95
WTF::IntHash::safeToCompareToEmptyOrDeleted
static const bool safeToCompareToEmptyOrDeleted
Definition: HashFunctions.h:96
WTF::IntHash::hash
static unsigned hash(T key)
Definition: HashFunctions.h:94
WTF::IntTypes< 1 >::SignedType
int8_t SignedType
Definition: HashFunctions.h:34
WTF::IntTypes< 1 >::UnsignedType
uint8_t UnsignedType
Definition: HashFunctions.h:34
WTF::IntTypes< 2 >::SignedType
int16_t SignedType
Definition: HashFunctions.h:35
WTF::IntTypes< 2 >::UnsignedType
uint16_t UnsignedType
Definition: HashFunctions.h:35
WTF::IntTypes< 4 >::UnsignedType
uint32_t UnsignedType
Definition: HashFunctions.h:36
WTF::IntTypes< 4 >::SignedType
int32_t SignedType
Definition: HashFunctions.h:36
WTF::IntTypes< 8 >::UnsignedType
uint64_t UnsignedType
Definition: HashFunctions.h:37
WTF::IntTypes< 8 >::SignedType
int64_t SignedType
Definition: HashFunctions.h:37
WTF::IntTypes
Definition: HashFunctions.h:33
WTF::PairHash
Definition: HashFunctions.h:135
WTF::PairHash::safeToCompareToEmptyOrDeleted
static const bool safeToCompareToEmptyOrDeleted
Definition: HashFunctions.h:144
WTF::PairHash::equal
static bool equal(const std::pair< T, U > &a, const std::pair< T, U > &b)
Definition: HashFunctions.h:140
WTF::PairHash::hash
static unsigned hash(const std::pair< T, U > &p)
Definition: HashFunctions.h:136
WTF::PtrHash< RefPtr< P > >::hash
static unsigned hash(const RefPtr< P > &key)
Definition: HashFunctions.h:124
WTF::PtrHash< RefPtr< P > >::equal
static bool equal(const RefPtr< P > &a, const RefPtr< P > &b)
Definition: HashFunctions.h:126
WTF::PtrHash< RefPtr< P > >::equal
static bool equal(const RefPtr< P > &a, P *b)
Definition: HashFunctions.h:128
WTF::PtrHash< RefPtr< P > >::equal
static bool equal(P *a, const RefPtr< P > &b)
Definition: HashFunctions.h:127
WTF::PtrHash
Definition: HashFunctions.h:107
WTF::PtrHash::safeToCompareToEmptyOrDeleted
static const bool safeToCompareToEmptyOrDeleted
Definition: HashFunctions.h:120
WTF::PtrHash::hash
static unsigned hash(T key)
Definition: HashFunctions.h:108
WTF::PtrHash::equal
static bool equal(T a, T b)
Definition: HashFunctions.h:119
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