topical media & game development

topical media & game development

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lib-of-vs-libs-Poco-include-Poco-HashStatistic.h / h


  //
  // HashStatistic.h
  //
  //  $Id: //poco/1.3/Foundation/include/Poco/HashStatistic.h#1$ 
  //
  // 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 <vector>
  
  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<UInt32> details = std::vector<UInt32>()); 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<UInt32> 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<UInt32> _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<UInt32> HashStatistic::detailedEntriesPerHash() const
  {
          return _detailedEntriesPerHash;
  }
  
  } // namespace Poco
  
  endif // Foundation_HashStatistic_INCLUDED

[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

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