include/AD/contain/hashbag.h

   1 //////////////////////////////////////////////////////////////////////////////
   2 // NOTICE:
   3 //
   4 // ADLib, Prop and their related set of tools and documentation are in the
   5 // public domain.   The author(s) of this software reserve no copyrights on
   6 // the source code and any code generated using the tools.  You are encouraged
   7 // to use ADLib and Prop to develop software, in both academic and commercial
   8 // settings, and are free to incorporate any part of ADLib and Prop into
   9 // your programs.
  10 //
  11 // Although you are under no obligation to do so, we strongly recommend that
  12 // you give away all software developed using our tools.
  13 //
  14 // We also ask that credit be given to us when ADLib and/or Prop are used in
  15 // your programs, and that this notice be preserved intact in all the source
  16 // code.
  17 //
  18 // This software is still under development and we welcome any suggestions
  19 // and help from the users.
  20 //
  21 // Allen Leung
  22 // 1994
  23 //////////////////////////////////////////////////////////////////////////////
  24
  25 #ifndef hash_table_based_bag_h
  26 #define hash_table_based_bag_h
  27
  28 ////////////////////////////////////////////////////////////////////////////
  29 // Bag (or Multisets) derived from a hash table
  30 ////////////////////////////////////////////////////////////////////////////
  31 #include <AD/contain/bag.h>  // Generic bags
  32
  33 template<class T, class H>
  34    class HashBag : public Bag<T> {
  35
  36       H bag;
  37
  38    public:
  39       //////////////////////////////////////////////////////////////////////
  40       // Inherit types
  41       //////////////////////////////////////////////////////////////////////
  42       typedef Bag<T>         Super;
  43       typedef Super::Element Element;
  44
  45       //////////////////////////////////////////////////////////////////////
  46       // Constructors and destructor
  47       //////////////////////////////////////////////////////////////////////
  48       HashBag(int size = Collection_default_size) : bag(size) {}
  49       HashBag(const HashBag& b) : Bag<T>(b.size()), bag(b.bag) {}
  50       HashBag(const Bag<T>& b) : bag(b.size()) { *this = b; }
  51      ~HashBag() {}
  52
  53       //////////////////////////////////////////////////////////////////////
  54       // Assignment
  55       //////////////////////////////////////////////////////////////////////
  56       // void operator = (const Bag<T>& b); // inherit
  57       void operator = (const HashBag<T,H>& b) { *this = (Bag<T>&)b; }
  58
  59       //////////////////////////////////////////////////////////////////////
  60       // Selectors:
  61       //    size()       return the number of elements within the bag.
  62       //    capacity()   return the current capacity.
  63       //    is_empty()   is the bag empty?
  64       //    contains()   does the bag contains the said element
  65       //    count()      returns the number of occurance of an element.
  66       //////////////////////////////////////////////////////////////////////
  67       // int  size() const;    // inherited
  68       // Bool is_empty() const; // inherited
  69       inline int  capacity() const           { return bag.capacity(); }
  70       inline Ix   lookup(const T& e) const   { return bag.lookup(e); }
  71       inline Bool contains(const T& e) const { return bag.contains(e); }
  72       inline int  count(const T& e) const
  73          { Ix i; return (i = bag.lookup(e)) ? 0 : bag.value(i); }
  74
  75       //////////////////////////////////////////////////////////////////////
  76       // In place multiset operations
  77       //////////////////////////////////////////////////////////////////////
  78       inline void clear()                  { bag.clear(); tally = 0; }
  79       Ix   insert(const T& e, int count);
  80       Bool remove(const T& e, int count);
  81       // Ix   insert(const T& e);      // inherited
  82       // Bool remove(const T& e);      // inherited
  83       // void Union      (const Bag<T>&); // inherited
  84       // void Difference (const Bag<T>&); // inherited
  85
  86       //////////////////////////////////////////////////////////////////////
  87       //  Iteration
  88       //////////////////////////////////////////////////////////////////////
  89       inline Ix  first()                 const { return bag.first(); }
  90       inline Ix  next(Ix i)              const { return bag.next(i); }
  91       inline const T& operator () (Ix i) const { return (T&)bag.key(i); }
  92       inline       T& operator () (Ix i)       { return (T&)bag.key(i); }
  93       inline int occurrence(Ix i)        const { return bag.value(i); }
  94
  95       //////////////////////////////////////////////////////////////////////
  96       //  Class name
  97       //////////////////////////////////////////////////////////////////////
  98       const char * myName() const { return "HashBag"; }
  99    };
 100
 101 //////////////////////////////////////////////////////////////////////
 102 // Insert a new element into the bag
 103 //////////////////////////////////////////////////////////////////////
 104 template <class T, class H>
 105    Ix HashBag<T, H>::insert(const T& e, int n)
 106    {  Ix total = bag.lookup(e);
 107       if (total) bag.value(total) += n; else total = bag.insert(e,n);
 108       tally += n;
 109       return total;
 110    }
 111
 112 //////////////////////////////////////////////////////////////////////
 113 // Remove an element
 114 //////////////////////////////////////////////////////////////////////
 115 template <class T, class H>
 116    Bool HashBag<T, H>::remove(const T& e, int n)
 117    {  Ix total = bag.lookup(e);
 118       if (total) {
 119          if (bag.value(total) > n) { bag.value(total) -= n; tally -= n; }
 120          else { tally -= bag.value(total); bag.remove(e); }
 121          return true;
 122       } else return false;
 123    }
 124
 125 #endif