list.h

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#ifndef LIST_CLASS
#define LIST_CLASS

/*****************************************************************************\
*                                                                             *
*  Name   : list                                                              *
*  Author : Chris Koeritz                                                     *
*                                                                             *
*******************************************************************************
* Copyright (c) 1998-$now By Author.  This program is free software; you can  *
* redistribute it and/or modify it under the terms of the GNU General Public  *
* License as published by the Free Software Foundation; either version 2 of   *
* the License or (at your option) any later version.  This is online at:      *
*     http://www.fsf.org/copyleft/gpl.html                                    *
* Please send any updates to: fred@gruntose.com                               *
\*****************************************************************************/

#include "node_dll.h"

namespace nodes {

class node;  // forward.


class NODES_CLASS_STYLE list
{
public:
  list();

  ~list();

  int elements() const;

  bool empty() const;



  class NODES_CLASS_STYLE iterator {
  public:
    iterator(const list *mgr, node *start) : _cursor(start), _manager(mgr) {}

    void operator ++();  
    void operator --();  
    void operator ++(int) { ++(*this); }  
    void operator --(int) { --(*this); }  

  
    inline void next() { (*this)++; }  
    inline void previous() { (*this)--; }  

    bool operator ==(const iterator &to_compare) const;
    bool operator !=(const iterator &tc) const { return !(*this == tc); }

    bool is_head() const;

    bool is_tail() const;

    void jump_head();  
    void jump_tail();  

    const node *observe();  

    node *access();  

  private:
    node *_cursor;  
    friend class list;  
    const list *_manager;  
  };

  iterator head() const { return iterator(this, _head); }
  iterator tail() const { return iterator(this, _tail); }

  int index(const iterator &it) const { return items_from_head(it); }

  bool set_index(iterator &to_set, int new_index);

  // storage and retrieval actions.
  // Note: all of these methods shift the iterator onto the next valid node
  // if it is positioned at the beginning or end of the list.

  void append(iterator &where, node *new_node);

  void insert(iterator &where, node *new_node);

  node *remove(iterator &where);

  void zap(iterator &where);

  void zap_all();

  // the following positioning functions could fail if the request is out of
  // bounds.  for example, forward cannot go beyond the end of the list.  in
  // such cases, false is returned and the list pointer is not moved.

  bool forward(iterator &where, int count);

  bool backward(iterator &where, int count);

  int items_from_head(const iterator &where) const;

  int items_from_tail(const iterator &where) const;

private:
  friend class iterator;
  node *_head;  
  node *_tail;  

  bool skip_or_ignore(iterator &where, int count);

  // not permitted.
  list(const list &);
  list &operator =(const list &);
};

} // namespace.

#endif

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