src/zserio/HashCodeUtil.h
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1 | | #ifndef ZSERIO_HASH_CODE_UTIL_H_INC |
2 | | #define ZSERIO_HASH_CODE_UTIL_H_INC |
3 | | |
4 | | #include <memory> |
5 | | #include <string> |
6 | | #include <type_traits> |
7 | | #include <vector> |
8 | | |
9 | | #include "zserio/Enums.h" |
10 | | #include "zserio/FloatUtil.h" |
11 | | #include "zserio/OptionalHolder.h" |
12 | | #include "zserio/Types.h" |
13 | | |
14 | | namespace zserio |
15 | | { |
16 | | |
17 | | /** Prime number for hash calculation. */ |
18 | | static const uint32_t HASH_PRIME_NUMBER = 37; |
19 | | /** Initial seed for hash calculation. */ |
20 | | static const uint32_t HASH_SEED = 23; |
21 | | |
22 | | /** |
23 | | * Gets initial hash code calculated from the given seed value. |
24 | | * |
25 | | * \param seedValue Seed value (current hash code). |
26 | | * |
27 | | * \return Hash code. |
28 | | */ |
29 | | inline uint32_t calcHashCodeFirstTerm(uint32_t seedValue) |
30 | 74 | { |
31 | 74 | return HASH_PRIME_NUMBER * seedValue; |
32 | 74 | } |
33 | | |
34 | | /** |
35 | | * Calculates hash code of the given integral value using the given seed value. |
36 | | * |
37 | | * \param seedValue Seed value (current hash code). |
38 | | * \param value Value for which to calculate the hash code. |
39 | | * |
40 | | * \return Calculated hash code. |
41 | | */ |
42 | | template <typename T> |
43 | | inline typename std::enable_if<std::is_integral<T>::value && (sizeof(T) <= 4), uint32_t>::type calcHashCode( |
44 | | uint32_t seedValue, T value) |
45 | 71 | { |
46 | 71 | return calcHashCodeFirstTerm(seedValue) + static_cast<uint32_t>(value); |
47 | 71 | } |
48 | | |
49 | | /** |
50 | | * Calculates hash code of the given integral value using the given seed value. |
51 | | * |
52 | | * \param seedValue Seed value (current hash code). |
53 | | * \param value Value for which to calculate the hash code. |
54 | | * |
55 | | * \return Calculated hash code. |
56 | | */ |
57 | | template <typename T> |
58 | | inline typename std::enable_if<std::is_integral<T>::value && (sizeof(T) > 4), uint32_t>::type calcHashCode( |
59 | | uint32_t seedValue, T value) |
60 | 3 | { |
61 | 3 | const auto unsignedValue = static_cast<typename std::make_unsigned<T>::type>(value); |
62 | 3 | return calcHashCodeFirstTerm(seedValue) + static_cast<uint32_t>(unsignedValue ^ (unsignedValue >> 32U)); |
63 | 3 | } |
64 | | |
65 | | /** |
66 | | * Calculates hash code of the given float value using the given seed value. |
67 | | * |
68 | | * \param seedValue Seed value (current hash code). |
69 | | * \param value Value for which to calculate the hash code. |
70 | | * |
71 | | * \return Calculated hash code. |
72 | | */ |
73 | | inline uint32_t calcHashCode(uint32_t seedValue, float value) |
74 | 1 | { |
75 | 1 | return calcHashCode(seedValue, convertFloatToUInt32(value)); |
76 | 1 | } |
77 | | |
78 | | /** |
79 | | * Calculates hash code of the given double value using the given seed value. |
80 | | * |
81 | | * \param seedValue Seed value (current hash code). |
82 | | * \param value Value for which to calculate the hash code. |
83 | | * |
84 | | * \return Calculated hash code. |
85 | | */ |
86 | | inline uint32_t calcHashCode(uint32_t seedValue, double value) |
87 | 1 | { |
88 | 1 | return calcHashCode(seedValue, convertDoubleToUInt64(value)); |
89 | 1 | } |
90 | | |
91 | | /** |
92 | | * Calculates hash code of the given string value using the given seed value. |
93 | | * |
94 | | * \param seedValue Seed value (current hash code). |
95 | | * \param stringValue Value for which to calculate the hash code. |
96 | | * |
97 | | * \return Calculated hash code. |
98 | | */ |
99 | | template <typename ALLOC> |
100 | | inline uint32_t calcHashCode( |
101 | | uint32_t seedValue, const std::basic_string<char, std::char_traits<char>, ALLOC>& stringValue) |
102 | 2 | { |
103 | 2 | uint32_t result = seedValue; |
104 | 2 | for (auto element : stringValue) |
105 | 2 | { |
106 | 2 | result = calcHashCode(result, element); |
107 | 2 | } |
108 | | |
109 | 2 | return result; |
110 | 2 | } |
111 | | |
112 | | /** |
113 | | * Calculates hash code of the given enum item using the given seed value. |
114 | | * |
115 | | * \param seedValue Seed value (current hash code). |
116 | | * \param enumValue Enum item for which to calculate the hash code. |
117 | | * |
118 | | * \return Calculated hash code. |
119 | | */ |
120 | | template <typename ENUM_TYPE> |
121 | | inline typename std::enable_if<std::is_enum<ENUM_TYPE>::value, uint32_t>::type calcHashCode( |
122 | | uint32_t seedValue, ENUM_TYPE enumValue) |
123 | 5 | { |
124 | 5 | return calcHashCode(seedValue, enumHashCode(enumValue)); |
125 | 5 | } |
126 | | |
127 | | /** |
128 | | * Calculates hash code of the given Zserio object (structure, choice, ...) using the given seed value. |
129 | | * |
130 | | * \param seedValue Seed value (current hash code). |
131 | | * \param object Object for which to calculate the hash code. |
132 | | * |
133 | | * \return Calculated hash code. |
134 | | */ |
135 | | template <typename OBJECT> |
136 | | inline typename std::enable_if<!std::is_enum<OBJECT>::value && !std::is_integral<OBJECT>::value, uint32_t>::type |
137 | | calcHashCode(uint32_t seedValue, const OBJECT& object) |
138 | 14 | { |
139 | 14 | return calcHashCode(seedValue, object.hashCode()); |
140 | 14 | } |
141 | | |
142 | | /** |
143 | | * Calculates hash code of the given Zserio array using the given seed value. |
144 | | * |
145 | | * \param seedValue Seed value (current hash code). |
146 | | * \param array Array for which to calculate the hash code. |
147 | | * |
148 | | * \return Calculated hash code. |
149 | | */ |
150 | | template <typename ARRAY_ELEMENT, typename ALLOC> |
151 | | inline uint32_t calcHashCode(uint32_t seedValue, const std::vector<ARRAY_ELEMENT, ALLOC>& array) |
152 | 11 | { |
153 | 11 | uint32_t result = seedValue; |
154 | 11 | for (const ARRAY_ELEMENT& element : array) |
155 | 16 | { |
156 | 16 | result = calcHashCode(result, element); |
157 | 16 | } |
158 | | |
159 | 11 | return result; |
160 | 11 | } |
161 | | |
162 | | // must be last because of the two-phase lookup |
163 | | // - we can have optional array (OptionalHolder<std::vector<T>>), but we cannot have array of optionals |
164 | | /** |
165 | | * Calculates hash code of the given Zserio optional field using the given seed value. |
166 | | * |
167 | | * \param seedValue Seed value (current hash code). |
168 | | * \param optionalHolder Optional field for which to calculate the hash code. |
169 | | * |
170 | | * \return Calculated hash code. |
171 | | */ |
172 | | template <typename FIELD> |
173 | | inline uint32_t calcHashCode(uint32_t seedValue, const InplaceOptionalHolder<FIELD>& optionalHolder) |
174 | 5 | { |
175 | 5 | if (!optionalHolder) |
176 | 1 | { |
177 | 1 | return calcHashCode(seedValue, 0); |
178 | 1 | } |
179 | | |
180 | 4 | return calcHashCode(seedValue, *optionalHolder); |
181 | 5 | } |
182 | | |
183 | | /** |
184 | | * Calculates hash code of the given Zserio optional field using the given seed value. |
185 | | * |
186 | | * \param seedValue Seed value (current hash code). |
187 | | * \param optionalHolder Optional field for which to calculate the hash code. |
188 | | * |
189 | | * \return Calculated hash code. |
190 | | */ |
191 | | template <typename FIELD, typename ALLOC> |
192 | | inline uint32_t calcHashCode(uint32_t seedValue, const HeapOptionalHolder<FIELD, ALLOC>& optionalHolder) |
193 | 2 | { |
194 | 2 | if (!optionalHolder) |
195 | 1 | { |
196 | 1 | return calcHashCode(seedValue, 0); |
197 | 1 | } |
198 | | |
199 | 1 | return calcHashCode(seedValue, *optionalHolder); |
200 | 2 | } |
201 | | |
202 | | } // namespace zserio |
203 | | |
204 | | #endif // ZSERIO_HASH_CODE_UTIL_H_INC |