include/AD/contain/linklist.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 doubly_linked_list_h
  26 #define doubly_linked_list_h
  27
  28 ///////////////////////////////////////////////////////////////////////////
  29 // Doubly linked list
  30 ///////////////////////////////////////////////////////////////////////////
  31
  32 #include <AD/generic/generic.h>  // Generic definitions
  33
  34 template <class T> class LinkedListIter;
  35
  36 template <class T>
  37    class LinkedList {
  38
  39       friend class LinkedListIter<T>;
  40
  41       struct Node {
  42          T element; Node * last, * next;
  43          Node (const T& e, Node * prev, Node * succ)
  44             : element(e), last(prev), next(succ) {}
  45       };
  46
  47       Node * front;                     // pointer to the beginning
  48       Node * back;                      // pointer to the end
  49       int size;                         // length of list
  50
  51       LinkedList(const LinkedList &);               // No copy constructor
  52       LinkedList& operator = (const LinkedList&);   // No assignment
  53
  54    public:
  55       class Unimplemented{};
  56
  57       LinkedList() : front(0), back(0), size(0) {}
  58      ~LinkedList();
  59
  60       int length() const                { return size; }
  61       Bool is_empty() const             { return size == 0; }
  62       T& head() const                   { return front->element; }
  63       T& tail() const                   { return back->element; }
  64       LinkedListIter<T> headPos() const { return LinkedListIter<T>(front); }
  65       LinkedListIter<T> tailPos() const { return LinkedListIter<T>(back); }
  66
  67       LinkedList& insert_before (const T& e, LinkedListIter<T>& i);
  68       LinkedList& insert_after  (const T& e, LinkedListIter<T>& i);
  69       LinkedList& delete_before (LinkedListIter<T>& i);
  70       LinkedList& delete_after  (LinkedListIter<T>& i);
  71
  72       LinkedList& insert_head (const T& e);
  73       LinkedList& insert_tail (const T& e);
  74       LinkedList& delete_head ();
  75       LinkedList& delete_tail ();
  76
  77       LinkedList& operator += (const T& e) { return insert_tail(e); }
  78    };
  79
  80 template <class T>
  81    class LinkedListIter {
  82       friend class LinkedList<T>;
  83       typename LinkedList<T>::Node * cursor;
  84       LinkedListIter(typename LinkedList<T>::Node * c) : cursor(c) {}
  85    public:
  86       LinkedListIter() : cursor(0) {}
  87       LinkedListIter(LinkedList<T>& list) : cursor(list.front) {}
  88      ~LinkedListIter() {}
  89
  90       void operator = (LinkedList<T>& list)   { cursor = list.front; }
  91       void operator = (LinkedListIter& i)           { cursor = i.cursor; }
  92
  93       operator typename LinkedList<T>::Node * () const { return cursor; }
  94
  95       void operator ++ (int)                  { cursor = cursor->next; }
  96       void operator ++ ()                     { cursor = cursor->next; }
  97       void operator -- (int)                  { cursor = cursor->last; }
  98       void operator -- ()                     { cursor = cursor->last; }
  99       T& operator () () const           { return cursor->element; }
 100    };
 101
 102
 103 ///////////////////////////////////////////////////////////////////////////
 104 // Implementation of the template methods
 105 ///////////////////////////////////////////////////////////////////////////
 106
 107 template <class T>
 108    LinkedList<T>::~LinkedList()
 109    {  Node * current, * succ;
 110       for (current = front; current; current = succ) {
 111          succ = current->next;
 112          delete current;
 113       }
 114    }
 115
 116 template <class T>
 117    inline LinkedList<T>& LinkedList<T>::insert_head(const T& e)
 118    {  Node * n = new Node(e,0,front);
 119       if (front) front->last = n;
 120       else back = n;
 121       front = n;
 122       size++;
 123       return *this;
 124    }
 125
 126 template <class T>
 127    inline LinkedList<T>& LinkedList<T>::insert_tail(const T& e)
 128    {  Node * n = new Node(e,back,0);
 129       if (back) back->next = n;
 130       else front = n;
 131       back = n;
 132       size++;
 133       return *this;
 134    }
 135
 136 template <class T>
 137    inline LinkedList<T>& LinkedList<T>::delete_head()
 138    {  Node * garbage = front;
 139       if (front == back) front = back = 0;
 140       else { front = front->next; front->last = 0; }
 141       delete garbage;
 142       size--;
 143       return *this;
 144    }
 145
 146 template <class T>
 147    inline LinkedList<T>& LinkedList<T>::delete_tail()
 148    {  Node * garbage = back;
 149       if (front == back) front = back = 0;
 150       else { back = back->last; back->next = 0; }
 151       delete garbage;
 152       size--;
 153       return *this;
 154    }
 155
 156 template <class T>
 157    LinkedList<T>& LinkedList<T>::insert_before
 158        (const T& e, LinkedListIter<T>& i)
 159    {  Node * n = new Node(e,i.cursor->last,i.cursor);
 160       i.cursor->last->next = n;
 161       i.cursor->last = n;
 162       size++;
 163       return *this;
 164    }
 165
 166 template <class T>
 167    LinkedList<T>& LinkedList<T>::insert_after
 168        (const T& e, LinkedListIter<T>& i)
 169    {  Node * n = new Node(e,i.cursor,i.cursor->next);
 170       i.cursor->next->last = n;
 171       i.cursor->next = n;
 172       size++;
 173       return *this;
 174    }
 175
 176 template <class T>
 177    LinkedList<T>& LinkedList<T>::delete_before(LinkedListIter<T>& i)
 178    {
 179       size--;
 180       return *this;
 181    }
 182
 183 template <class T>
 184    LinkedList<T>& LinkedList<T>::delete_after(LinkedListIter<T>& i)
 185    {
 186       size--;
 187       return *this;
 188    }
 189
 190 #endif