1 | // |
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2 | // HashStatistic.h |
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3 | // |
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4 | // $Id: //poco/1.3/Foundation/include/Poco/HashStatistic.h#1 $ |
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5 | // |
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6 | // Library: Foundation |
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7 | // Package: Hashing |
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8 | // Module: HashStatistic |
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9 | // |
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10 | // Definition of the HashStatistic class. |
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11 | // |
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12 | // Copyright (c) 2006, Applied Informatics Software Engineering GmbH. |
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13 | // and Contributors. |
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14 | // |
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15 | // Permission is hereby granted, free of charge, to any person or organization |
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16 | // obtaining a copy of the software and accompanying documentation covered by |
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17 | // this license (the "Software") to use, reproduce, display, distribute, |
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18 | // execute, and transmit the Software, and to prepare derivative works of the |
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19 | // Software, and to permit third-parties to whom the Software is furnished to |
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20 | // do so, all subject to the following: |
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21 | // |
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22 | // The copyright notices in the Software and this entire statement, including |
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23 | // the above license grant, this restriction and the following disclaimer, |
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24 | // must be included in all copies of the Software, in whole or in part, and |
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25 | // all derivative works of the Software, unless such copies or derivative |
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26 | // works are solely in the form of machine-executable object code generated by |
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27 | // a source language processor. |
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28 | // |
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29 | // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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30 | // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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31 | // FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT |
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32 | // SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE |
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33 | // FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, |
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34 | // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
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35 | // DEALINGS IN THE SOFTWARE. |
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36 | // |
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37 | |
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38 | |
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39 | #ifndef Foundation_HashStatistic_INCLUDED |
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40 | #define Foundation_HashStatistic_INCLUDED |
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41 | |
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42 | |
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43 | #include "Poco/Foundation.h" |
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44 | #include <vector> |
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45 | |
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46 | |
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47 | namespace Poco { |
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48 | |
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49 | |
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50 | //@ deprecated |
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51 | class Foundation_API HashStatistic |
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52 | /// HashStatistic class bundles statistical information on the current state of a HashTable |
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53 | { |
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54 | public: |
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55 | HashStatistic( |
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56 | UInt32 tableSize, |
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57 | UInt32 numEntries, |
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58 | UInt32 numZeroEntries, |
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59 | UInt32 maxEntry, |
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60 | std::vector<UInt32> details = std::vector<UInt32>()); |
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61 | /// Creates the HashStatistic. |
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62 | |
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63 | virtual ~HashStatistic(); |
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64 | /// Destroys the HashStatistic. |
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65 | |
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66 | UInt32 maxPositionsOfTable() const; |
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67 | /// Returns the maximum number of different hash values possible for the table |
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68 | |
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69 | UInt32 numberOfEntries() const; |
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70 | /// Returns the total number of entries currently stored in the HashTable |
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71 | |
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72 | UInt32 numberOfZeroPositions() const; |
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73 | /// Returns the number of hash positions that contain no entry. |
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74 | |
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75 | double avgEntriesPerHash() const; |
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76 | /// Returns the average number of entries per position in the Hashtable, the higher this value the less efficient |
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77 | /// performs hashing. If a large value is returned and getNumberOfZeroPositions also returns a large value, this |
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78 | /// indicates an inefficient hashing function. If the number of zero entries is low, resizing the HashTable, should |
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79 | /// be enough to improve performance |
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80 | |
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81 | double avgEntriesPerHashExclZeroEntries() const; |
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82 | /// Same as getAvgEntriesPerHash but hash values that contain no entry are ignored, |
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83 | /// getAvgEntriesPerHashExclZeroEntries >= getAvgEntriesPerHash will always be true. |
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84 | |
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85 | UInt32 maxEntriesPerHash() const; |
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86 | /// Returns the maximum number of entries per hash value found in the current table. |
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87 | |
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88 | const std::vector<UInt32> detailedEntriesPerHash() const; |
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89 | /// Will either be an empty vector or will contain for each possible hash value, the number of entries currently stored |
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90 | |
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91 | std::string toString() const; |
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92 | /// Converts the whole data structure into a string. |
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93 | |
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94 | private: |
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95 | UInt32 _sizeOfTable; |
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96 | UInt32 _numberOfEntries; |
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97 | UInt32 _numZeroEntries; |
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98 | UInt32 _maxEntriesPerHash; |
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99 | std::vector<UInt32> _detailedEntriesPerHash; |
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100 | }; |
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101 | |
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102 | |
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103 | inline UInt32 HashStatistic::maxPositionsOfTable() const |
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104 | { |
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105 | return _sizeOfTable; |
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106 | } |
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107 | |
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108 | |
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109 | inline UInt32 HashStatistic::numberOfEntries() const |
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110 | { |
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111 | return _numberOfEntries; |
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112 | } |
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113 | |
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114 | |
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115 | inline UInt32 HashStatistic::numberOfZeroPositions() const |
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116 | { |
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117 | return _numZeroEntries; |
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118 | } |
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119 | |
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120 | |
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121 | inline double HashStatistic::avgEntriesPerHash() const |
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122 | { |
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123 | return ((double) numberOfEntries()) / maxPositionsOfTable(); |
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124 | } |
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125 | |
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126 | |
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127 | inline double HashStatistic::avgEntriesPerHashExclZeroEntries() const |
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128 | { |
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129 | return ((double) numberOfEntries()) / (maxPositionsOfTable() - numberOfZeroPositions()); |
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130 | } |
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131 | |
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132 | |
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133 | inline UInt32 HashStatistic::maxEntriesPerHash() const |
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134 | { |
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135 | return _maxEntriesPerHash; |
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136 | } |
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137 | |
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138 | |
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139 | inline const std::vector<UInt32> HashStatistic::detailedEntriesPerHash() const |
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140 | { |
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141 | return _detailedEntriesPerHash; |
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142 | } |
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143 | |
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144 | |
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145 | } // namespace Poco |
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146 | |
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147 | |
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148 | #endif // Foundation_HashStatistic_INCLUDED |
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