Embedded Template Library 1.0
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pearson.h
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1
2
3/******************************************************************************
4The MIT License(MIT)
5
6Embedded Template Library.
7https://github.com/ETLCPP/etl
8https://www.etlcpp.com
9
10Copyright(c) 2014 John Wellbelove
11
12Permission is hereby granted, free of charge, to any person obtaining a copy
13of this software and associated documentation files(the "Software"), to deal
14in the Software without restriction, including without limitation the rights
15to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
16copies of the Software, and to permit persons to whom the Software is
17furnished to do so, subject to the following conditions :
18
19The above copyright notice and this permission notice shall be included in all
20copies or substantial portions of the Software.
21
22THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
25AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
27OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
28SOFTWARE.
29******************************************************************************/
30
31#ifndef ETL_PEARSON_INCLUDED
32#define ETL_PEARSON_INCLUDED
33
34#include "platform.h"
35#include "static_assert.h"
36#include "type_traits.h"
37#include "ihash.h"
38#include "array.h"
39#include "iterator.h"
40
41#include <stdint.h>
42
43ETL_STATIC_ASSERT(ETL_USING_8BIT_TYPES, "This file does not currently support targets with no 8bit type");
44
45#if defined(ETL_COMPILER_KEIL)
46#pragma diag_suppress 1300
47#endif
48
51
52namespace etl
53{
54 //***************************************************************************
58 //***************************************************************************
59 template <size_t HASH_LENGTH>
60 class pearson
61 {
62 public:
63
65
66 //*************************************************************************
68 //*************************************************************************
70 : first(true)
71 {
72 reset();
73 }
74
75 //*************************************************************************
79 //*************************************************************************
80 template<typename TIterator>
82 : first(true)
83 {
84 ETL_STATIC_ASSERT(sizeof(typename etl::iterator_traits<TIterator>::value_type) == 1, "Type not supported");
85
86 reset();
87 add(begin, end);
88 }
89
90 //*************************************************************************
92 //*************************************************************************
93 void reset()
94 {
95 hash.fill(0);
96 }
97
98 //*************************************************************************
102 //*************************************************************************
103 template<typename TIterator>
105 {
106 ETL_STATIC_ASSERT(sizeof(typename etl::iterator_traits<TIterator>::value_type) == 1, "Type not supported");
107
108 while (begin != end)
109 {
110 add(*begin);
111 ++begin;
112 }
113 }
114
115 //*************************************************************************
117 //*************************************************************************
119 {
120 static ETL_CONSTANT uint8_t PEARSON_LOOKUP[] =
121 {
122 228, 39, 61, 95, 227, 187, 0, 197, 31, 189, 161, 222, 34, 15, 221, 246,
123 19, 234, 6, 50, 113, 3, 91, 63, 77, 245, 144, 2, 183, 196, 25, 226,
124 97, 126, 48, 59, 217, 4, 100, 145, 12, 88, 203, 149, 80, 154, 38, 27,
125 224, 218, 158, 115, 202, 79, 53, 83, 242, 36, 139, 131, 136, 191, 42, 170,
126 23, 99, 156, 51, 143, 60, 233, 206, 62, 108, 17, 67, 81, 71, 93, 195,
127 26, 231, 247, 96, 24, 200, 176, 209, 152, 212, 138, 165, 75, 185, 130, 248,
128 125, 110, 10, 116, 201, 90, 69, 204, 85, 251, 78, 157, 47, 184, 169, 141,
129 134, 230, 89, 21, 146, 46, 55, 128, 148, 207, 216, 11, 114, 199, 103, 102,
130 166, 244, 5, 104, 225, 160, 132, 28, 172, 65, 121, 140, 153, 119, 198, 210,
131 58, 87, 117, 177, 33, 22, 13, 37, 49, 174, 109, 40, 73, 211, 18, 167,
132 164, 252, 168, 74, 30, 173, 35, 98, 66, 193, 94, 175, 86, 54, 179, 122,
133 220, 151, 192, 29, 133, 254, 155, 127, 240, 232, 190, 180, 8, 68, 236, 20,
134 137, 92, 219, 208, 52, 250, 147, 142, 111, 112, 120, 45, 135, 255, 123, 229,
135 57, 182, 243, 124, 186, 253, 7, 237, 9, 16, 70, 171, 235, 107, 223, 118,
136 215, 178, 194, 181, 43, 188, 106, 105, 64, 241, 84, 238, 159, 44, 32, 76,
137 213, 163, 150, 101, 129, 14, 249, 205, 214, 1, 41, 56, 162, 72, 239, 82
138 };
139
140 if (first)
141 {
142 for (size_t i = 0UL; i < HASH_LENGTH; ++i)
143 {
144 hash[i] = PEARSON_LOOKUP[(uint32_t(value_) + i) % 256];
145 }
146
147 first = false;
148 }
149 else
150 {
151 for (size_t i = 0UL; i < HASH_LENGTH; ++i)
152 {
153 hash[i] = PEARSON_LOOKUP[hash[i] ^ value_];
154 }
155 }
156 }
157
158 //*************************************************************************
160 //*************************************************************************
162 {
163 return hash;
164 }
165
166 //*************************************************************************
168 //*************************************************************************
169 operator value_type () const
170 {
171 return value();
172 }
173
174 private:
175
176 bool first;
177 value_type hash;
178 };
179}
180
181#endif
ETL_CONSTEXPR14 void fill(parameter_t value)
Definition array.h:374
void add(uint8_t value_)
Definition pearson.h:118
void reset()
Resets the hash to the initial state.
Definition pearson.h:93
value_type value() const
Gets the hash value.
Definition pearson.h:161
void add(TIterator begin, const TIterator end)
Definition pearson.h:104
pearson(TIterator begin, const TIterator end)
Definition pearson.h:81
pearson()
Default constructor.
Definition pearson.h:69
Definition pearson.h:61
bitset_ext
Definition absolute.h:38
ETL_CONSTEXPR TContainer::iterator begin(TContainer &container)
Definition iterator.h:962
ETL_CONSTEXPR TContainer::iterator end(TContainer &container)
Definition iterator.h:992
pair holds two objects of arbitrary type
Definition utility.h:164