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HashMap.h

//
// HashMap.h
//
// $Id: //poco/1.3/Foundation/include/Poco/HashMap.h#1 $
//
// Library: Foundation
// Package: Hashing
// Module:  HashMap
//
// Definition of the HashMap 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_HashMap_INCLUDED
#define Foundation_HashMap_INCLUDED


#include "Poco/Foundation.h"
#include "Poco/LinearHashTable.h"
#include "Poco/Exception.h"
#include <utility>


namespace Poco {


template <class Key, class Value>
00053 struct HashMapEntry
      /// This class template is used internally by HashMap.
{
      Key   first;
      Value second;
      
      HashMapEntry():
            first(),
            second()
      {
      }
      
      HashMapEntry(const Key& key):
            first(key),
            second()
      {
      }

      HashMapEntry(const Key& key, const Value& value):
            first(key),
            second(value)
      {
      }
      
      bool operator == (const HashMapEntry& entry) const
      {
            return first == entry.first;
      }

      bool operator != (const HashMapEntry& entry) const
      {
            return first != entry.first;
      }
};


template <class HME, class KeyHashFunc>
00090 struct HashMapEntryHash
      /// This class template is used internally by HashMap.
{
      std::size_t operator () (const HME& entry) const
      {
            return _func(entry.first);
      }

private:
      KeyHashFunc _func;
};


template <class Key, class Mapped, class HashFunc = Hash<Key> >
00104 class HashMap
      /// This class implements a map using a LinearHashTable.
      ///
      /// A HashMap can be used just like a std::map.
{
public:
      typedef Key                 KeyType;
      typedef Mapped              MappedType;
      typedef Mapped&             Reference;
      typedef const Mapped&       ConstReference;
      typedef Mapped*             Pointer;
      typedef const Mapped*       ConstPointer;
      
      typedef HashMapEntry<Key, Mapped>      ValueType;
      typedef std::pair<KeyType, MappedType> PairType;
      
      typedef HashMapEntryHash<ValueType, HashFunc> HashType;
      typedef LinearHashTable<ValueType, HashType>  HashTable;
      
      typedef typename HashTable::Iterator      Iterator;
      typedef typename HashTable::ConstIterator ConstIterator;
      
00126       HashMap()
            /// Creates an empty HashMap.
      {
      }
      
      HashMap(std::size_t initialReserve):
            _table(initialReserve)
            /// Creates the HashMap with room for initialReserve entries.
      {
      }
      
00137       HashMap& operator = (const HashMap& map)
            /// Assigns another HashMap.
      {
            HashMap tmp(map);
            swap(tmp);
            return *this;
      }
      
00145       void swap(HashMap& map)
            /// Swaps the HashMap with another one.
      {
            _table.swap(map._table);
      }
      
      ConstIterator begin() const
      {
            return _table.begin();
      }
      
      ConstIterator end() const
      {
            return _table.end();
      }
      
      Iterator begin()
      {
            return _table.begin();
      }
      
      Iterator end()
      {
            return _table.end();
      }
      
      ConstIterator find(const KeyType& key) const
      {
            ValueType value(key);
            return _table.find(value);
      }

      Iterator find(const KeyType& key)
      {
            ValueType value(key);
            return _table.find(value);
      }

      std::pair<Iterator, bool> insert(const PairType& pair)
      {
            ValueType value(pair.first, pair.second);
            return _table.insert(value);
      }

      std::pair<Iterator, bool> insert(const ValueType& value)
      {
            return _table.insert(value);
      }
      
      void erase(Iterator it)
      {
            _table.erase(it);
      }
      
      void erase(const KeyType& key)
      {
            Iterator it = find(key);
            _table.erase(it);
      }
      
      void clear()
      {
            _table.clear();
      }

      std::size_t size() const
      {
            return _table.size();
      }

      bool empty() const
      {
            return _table.empty();
      }

      ConstReference operator [] (const KeyType& key) const
      {
            ConstIterator it = _table.find(key);
            if (it != _table.end())
                  return it->second;
            else
                  throw NotFoundException();
      }

      Reference operator [] (const KeyType& key)
      {
            ValueType value(key);
            std::pair<Iterator, bool> res = _table.insert(value);
            return res.first->second;
      }

private:
      HashTable _table;
};


} // namespace Poco


#endif // Foundation_HashMap_INCLUDED

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