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HashTable.h

//   -*- C++ -*-
/*****************************************************************************
 *
 *   |_|_|_  |_|_    |_    |_|_|_  |_                C O M M U N I C A T I O N
 * |_        |_  |_  |_  |_        |_                          N E T W O R K S
 * |_        |_  |_  |_  |_        |_                                C L A S S
 *   |_|_|_  |_    |_|_    |_|_|_  |_|_|_|_                      L I B R A R Y
 *
 * $Id: HashTable.h,v 1.4 2002/01/14 11:04:34 spee Exp $
 *
 * CNClass: CNHashTable --- Abstract base class for hash tables
 *
 *****************************************************************************
 * Copyright (C) 1992-2002   Communication Networks
 *                           Aachen University of Technology
 *                           D-52056 Aachen
 *                           Germany
 *                           Email: cncl-adm@comnets.rwth-aachen.de
 *****************************************************************************
 * This file is part of the CN class library. All files marked with
 * this header are free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.  This library is
 * distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
 * License for more details.  You should have received a copy of the GNU
 * Library General Public License along with this library; if not, write
 * to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
 * USA.
 *****************************************************************************/

#ifndef __HashTable_h
#define __HashTable_h

#include <CNCL/Class.h>
#include <CNCL/Param.h>

#include <CNCL/Object.h>                // Base class

extern CNClassDesc CN_HASHTABLE;        // CNClass CNHashTable description

#include <CNCL/Key.h>


const unsigned long DEFAULT_HASH_TABLE_CAPACITY = 101;


struct HashEntry {
    CNKey *he_CNKey;
    unsigned long he_HashValue;
};

// forwards
class CNHashIterator;

class CNHashTable : public CNObject
{
protected:
    friend class CNHashIterator;

    virtual struct HashEntry *HashTable() const = 0;

    enum rmKeyType
    {
        clearKeyOnly, freeMemOfKey, freeMemOfKeyAndObject
    };

public:
    virtual void store_key(CNKey *k) = 0;
    virtual void store_key(CNKey &k) = 0;
    
    virtual CNKey *get_key(const CNKey *k) const = 0;
    virtual CNKey *get_key(const CNKey &k) const = 0;
        
    virtual CNObject *get_object(const CNKey *k) const = 0;
    virtual CNObject *get_object(const CNKey &k) const = 0;
        
    virtual bool reset_absolutely() = 0;
    virtual bool reset_absolutely_w_obj() = 0;
    virtual bool delete_key(const CNKey *k) = 0;
    virtual bool delete_key(const CNKey &k) 
    { return delete_key(&k); }
    virtual bool delete_key_absolutely(const CNKey *k) = 0;
    virtual bool delete_key_absolutely(const CNKey &k) = 0;
    virtual bool delete_key_absolutely_w_obj(const CNKey *k) = 0;
    virtual bool delete_key_absolutely_w_obj(const CNKey &k) = 0;
        
    virtual bool is_full() const = 0;
    virtual bool is_empty() const = 0;
    virtual unsigned long get_capacity() const = 0;
    virtual unsigned long get_num_entries() const = 0;
        
    /****** Constructors ******************************************************/
public:
    CNHashTable() {}
    CNHashTable(CNParam *) {}                   

    /****** Member functions required by CNCL *********************************/
public:
    virtual CNClassDesc class_desc() const      // CNClass description
    {
        return CN_HASHTABLE;
    };
            
    virtual bool is_a(CNClassDesc desc) const
    {
        return desc == CN_HASHTABLE ? TRUE : CNObject::is_a(desc);
    };
        
    static CNHashTable *cast_from_object(CNObject *obj)
    {
#   ifdef NO_TYPE_CHECK
        return (CNHashTable *)obj;
#   else
        return (CNHashTable *)( !obj || obj->is_a(CN_HASHTABLE)
               ? obj : fatal_type(obj->class_desc(), CN_HASHTABLE) );
#   endif
    }
    
    virtual void print(ostream &strm = cout) const = 0;
    virtual void dump (ostream &strm = cout) const = 0;
};

#endif 

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