legoHash.H

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/**************************************************************************
 *
 * File:         legoHash.H
 * Author:       Bill Havanki
 * Description:  Describes a generic hash table.
 *
 * 10/17/97 WAH: Added notfound field and associated methods.
 * 10/24/97 WAH: Converted implementation to use STL map container.
 * 10/30/97 WAH: Added DeleteAll method.
 * 1/6/98 WAH:   Removed old implementation.
 **************************************************************************/

#ifndef LEGOHASH_H
#define LEGOHASH_H

//#define LEGOHASH_DEBUG

#include <iostream.h>
#include <stl.h>
#include "legoErr.H"

/*
 * class legoHash
 *
 * This class describes a single hash table of arbitrary size.
 */
template <class T1, class T2, class T3>
class legoHash
{
  map <T1, T2, T3> *table;
  map <T1, T2, T3>::iterator it;
  int notfound;

public:
  legoHash() { table = new map <T1, T2, T3>; }
  ~legoHash() { delete table; }

  T2 Lookup (T1 key)
  {
    map<T1, T2, T3>::iterator i;

    i = table->find (key);
    if (i == table->end())
      notfound = 1;
    else
      notfound = 0;
    return (*i).second;
  } // end Lookup

  int NotFound (void) { return notfound; }

  void Set (T1 key, T2 value)
  {
    (*table)[key] = value;
  } // end Set

  void Delete (T1 key)
  {
    table->erase (key);
  } // end Delete

  void DeleteAll (void)
  {
    table->erase (table->begin(), table->end());
  } // end DeleteAll

  // Iterator functions

  void Start (void)
  {
    it = table->begin();
  }
  void Next (void) { it++; }
  int AtEnd (void) { return (it == table->end()); } 
  T1 GetCurrentKey (void) { return (*it).first; }
  T2 LookupCurrent (void) { return (*it).second; }

}; // end class legoHash

// Comparison functions required for hash table usage.
struct legoHash_lt_string
{
  bool operator()(const char* s1, const char* s2) const
  {
    return strcmp(s1, s2) < 0;
  }
};

struct legoHash_lt_int
{
  bool operator()(const int i1, const int i2) const
  {
    return (i1 < i2);
  }
};

struct legoHash_lt_pointer
{
  bool operator()(const void *i1, const void *i2) const
  {
    return ((unsigned long) i1 < (unsigned long) i2);
  }
};

#endif

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