// utl_list.h,v 1.4 1998/10/20 02:32:48 levine Exp

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 *Copyright 1992 Sun Microsystems, Inc.
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#ifndef _UTL_LIST_UTL_LIST_HH
#define _UTL_LIST_UTL_LIST_HH

// utl_list.hh
//
// General single-linked lists

/*
** DEPENDENCIES: NONE
**
** USE: Included from util.hh
*/

// Forward declare active iterator for UTL_List
template<class L, class T> class UTL_ListActiveIterator;

template<class L, class T>
class   UTL_List
{
public:
  // Operations

  // Constructor(s)
  UTL_List(T *c, L *l);
  virtual ~UTL_List() {}

  // Smash last cdr pointer in "this" with l
  void                  nconc(L *l);

  // Copy the list starting at "this"
  L                     *copy();

  // Get list element
  T                     *head();

  // Get next list
  L                     *tail();

  // Set the list element
  void                  set_head(T *t);

  // Set next list
  void                  set_tail(L *l);

  // How long is this list?
  long                  length();

private:
  // Data
  T                     *pd_car_data;   // The next list
  L                     *pd_cdr_data;   // The next list

  // Operations
  long                  list_length(long n); // How long is it?

  // Friend class
  friend class          UTL_ListActiveIterator<L, T>; // Friend class

};

// Active iterator for lists
template<class L, class T>
class   UTL_ListActiveIterator
{
public:
  // Operations

  // Constructor(s)
  UTL_ListActiveIterator(UTL_List<L, T> *s);
  virtual ~UTL_ListActiveIterator() {}

  // Get current item
  T                     *item();

  // Get next list
  virtual void          next();

  // Are we at the end of this list?
  virtual long          is_done();

protected:
  // Data
  UTL_List<L, T>                *source;                // On what to iterate?
};

#endif           // _UTL_LIST_UTL_LIST_HH
