// // HashStatistic.h // // $Id: //poco/1.4/Foundation/include/Poco/HashStatistic.h#1 $ // // Library: Foundation // Package: Hashing // Module: HashStatistic // // Definition of the HashStatistic class. // // Copyright (c) 2006, Applied Informatics Software Engineering GmbH. // and Contributors. // // Permission is hereby granted, free of charge, to any person or organization // obtaining a copy of the software and accompanying documentation covered by // this license (the "Software") to use, reproduce, display, distribute, // execute, and transmit the Software, and to prepare derivative works of the // Software, and to permit third-parties to whom the Software is furnished to // do so, all subject to the following: // // The copyright notices in the Software and this entire statement, including // the above license grant, this restriction and the following disclaimer, // must be included in all copies of the Software, in whole or in part, and // all derivative works of the Software, unless such copies or derivative // works are solely in the form of machine-executable object code generated by // a source language processor. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT // SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE // FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER // DEALINGS IN THE SOFTWARE. // #ifndef Foundation_HashStatistic_INCLUDED #define Foundation_HashStatistic_INCLUDED #include "Poco/Foundation.h" #include namespace Poco { //@ deprecated class Foundation_API HashStatistic /// HashStatistic class bundles statistical information on the current state of a HashTable { public: HashStatistic( UInt32 tableSize, UInt32 numEntries, UInt32 numZeroEntries, UInt32 maxEntry, std::vector details = std::vector()); /// Creates the HashStatistic. virtual ~HashStatistic(); /// Destroys the HashStatistic. UInt32 maxPositionsOfTable() const; /// Returns the maximum number of different hash values possible for the table UInt32 numberOfEntries() const; /// Returns the total number of entries currently stored in the HashTable UInt32 numberOfZeroPositions() const; /// Returns the number of hash positions that contain no entry. double avgEntriesPerHash() const; /// Returns the average number of entries per position in the Hashtable, the higher this value the less efficient /// performs hashing. If a large value is returned and getNumberOfZeroPositions also returns a large value, this /// indicates an inefficient hashing function. If the number of zero entries is low, resizing the HashTable, should /// be enough to improve performance double avgEntriesPerHashExclZeroEntries() const; /// Same as getAvgEntriesPerHash but hash values that contain no entry are ignored, /// getAvgEntriesPerHashExclZeroEntries >= getAvgEntriesPerHash will always be true. UInt32 maxEntriesPerHash() const; /// Returns the maximum number of entries per hash value found in the current table. const std::vector detailedEntriesPerHash() const; /// Will either be an empty vector or will contain for each possible hash value, the number of entries currently stored std::string toString() const; /// Converts the whole data structure into a string. private: UInt32 _sizeOfTable; UInt32 _numberOfEntries; UInt32 _numZeroEntries; UInt32 _maxEntriesPerHash; std::vector _detailedEntriesPerHash; }; inline UInt32 HashStatistic::maxPositionsOfTable() const { return _sizeOfTable; } inline UInt32 HashStatistic::numberOfEntries() const { return _numberOfEntries; } inline UInt32 HashStatistic::numberOfZeroPositions() const { return _numZeroEntries; } inline double HashStatistic::avgEntriesPerHash() const { return ((double) numberOfEntries()) / maxPositionsOfTable(); } inline double HashStatistic::avgEntriesPerHashExclZeroEntries() const { return ((double) numberOfEntries()) / (maxPositionsOfTable() - numberOfZeroPositions()); } inline UInt32 HashStatistic::maxEntriesPerHash() const { return _maxEntriesPerHash; } inline const std::vector HashStatistic::detailedEntriesPerHash() const { return _detailedEntriesPerHash; } } // namespace Poco #endif // Foundation_HashStatistic_INCLUDED