text: /**********************************************************************
   * File:        elst.h  (Formerly elist.h)
   * Description: Embedded list module include file.
   * Author:      Phil Cheatle
   * Created:     Mon Jan 07 08:35:34 GMT 1991
   *
   * (C) Copyright 1991, Hewlett-Packard Ltd.
   ** Licensed under the Apache License, Version 2.0 (the "License");
   ** you may not use this file except in compliance with the License.
   ** You may obtain a copy of the License at
   ** http://www.apache.org/licenses/LICENSE-2.0
   ** Unless required by applicable law or agreed to in writing, software
   ** distributed under the License is distributed on an "AS IS" BASIS,
   ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   ** See the License for the specific language governing permissions and
   ** limitations under the License.
   *
   **********************************************************************/
  
  #ifndef ELST_H
  #define ELST_H
  
  #include <stdio.h>
  #include "host.h"
  #include "serialis.h"
  #include "lsterr.h"
  
  class ELIST_ITERATOR;
  
  /**********************************************************************
  This module implements list classes and iterators.
  The following list types and iterators are provided:
  
    List type        List Class      Iterator Class     Element Class
    ---------         ----------      --------------      -------------
  
      Embedded list       ELIST
                ELIST_ITERATOR
                ELIST_LINK
      (Single linked)
  
      Embedded list       ELIST2
                ELIST2_ITERATOR
                ELIST2_LINK
      (Double linked)
  
      Cons List           CLIST
                CLIST_ITERATOR
                CLIST_LINK
      (Single linked)
  
      Cons List           CLIST2
                CLIST2_ITERATOR
                CLIST2_LINK
      (Double linked)
  
  An embedded list is where the list pointers are provided by a generic class.
  Data types to be listed inherit from the generic class.  Data is thus linked
  in only ONE list at any one time.
  
  A cons list has a separate structure for a "cons cell".  This contains the
  list pointer(s) AND a pointer to the data structure held on the list.  A
  structure can be on many cons lists at the same time, and the structure does
  not need to inherit from any generic class in order to be on the list.
  
  The implementation of lists is very careful about space and speed overheads.
  This is why many embedded lists are provided. The same concerns mean that
  in-line type coercion is done, rather than use virtual functions.  This is
  cumbersome in that each data type to be listed requires its own iterator and
  list class - though macros can gererate these.  It also prevents heterogenous
  lists.
  **********************************************************************/
  
  /**********************************************************************
   *                          CLASS - ELIST_LINK
   *
   *                          Generic link class for singly linked lists with embedded links
   *
   *  Note:  No destructor - elements are assumed to be destroyed EITHER after
   *  they have been extracted from a list OR by the ELIST destructor which
   *  walks the list.
   **********************************************************************/
  
  class DLLSYM ELIST_LINK
  {
    friend class ELIST_ITERATOR;
    friend class ELIST;
  
    ELIST_LINK *next;
  
    public:
      ELIST_LINK() {
        next = NULL;
      }
      //constructor
  
      ELIST_LINK(                       //copy constructor
                 const ELIST_LINK &) {  //dont copy link
        next = NULL;
      }
  
      void operator= (             //dont copy links
      const ELIST_LINK &) {
        next = NULL;
      }
  
      void serialise_asc(  //serialise to ascii
                         FILE *f);
      void de_serialise_asc(  //de-serialise from ascii
                            FILE *f);
  
      /* NOTE that none of the serialise member functions are required for
      ELIST_LINKS as they are never serialised.  (We demand that the derived
      class terminates recursion - just to make sure that it defines the member
      functions anyway.)
      */
  };
  
  /**********************************************************************
   * CLASS - ELIST
   *
   * Generic list class for singly linked lists with embedded links
   **********************************************************************/
  
  class DLLSYM ELIST
  {
    friend class ELIST_ITERATOR;
  
    ELIST_LINK *last;              //End of list
    //(Points to head)
    ELIST_LINK *First() {  // return first
      return last ? last->next : NULL;
    }
  
    public:
      ELIST() {  //constructor
        last = NULL;
      }
  
      void internal_clear (        //destroy all links
                                   //ptr to zapper functn
        void (*zapper) (ELIST_LINK *));
  
      BOOL8 empty() {  //is list empty?
        return !last;
      }
  
      BOOL8 singleton() {
        return last ? (last == last->next) : FALSE;
      }
  
      void shallow_copy(                     //dangerous!!
                        ELIST *from_list) {  //beware destructors!!
        last = from_list->last;
      }
  
                                   //ptr to copier functn
      void internal_deep_copy (ELIST_LINK * (*copier) (ELIST_LINK *),
        const ELIST * list);       //list being copied
  
      void assign_to_sublist(                           //to this list
                             ELIST_ITERATOR *start_it,  //from list start
                             ELIST_ITERATOR *end_it);   //from list end
  
      inT32 length();  //# elements in list
  
      void sort (                  //sort elements
        int comparator (           //comparison routine
        const void *, const void *));
  
      // Assuming list has been sorted already, insert new_link to
      // keep the list sorted according to the same comparison function.
      // Comparision function is the same as used by sort, i.e. uses double
      // indirection. Time is O(1) to add to beginning or end.
      // Time is linear to add pre-sorted items to an empty list.
      void add_sorted(int comparator(const void*, const void*),
                      ELIST_LINK* new_link);
  
      void internal_dump (         //serialise each elem
        FILE * f,                  //to this file
        void element_serialiser (  //using this function
        FILE *, ELIST_LINK *));
  
      void internal_de_dump (      //de_serial each elem
        FILE * f,                  //from this file
                                   //using this function
        ELIST_LINK * element_de_serialiser (
        FILE *));
  
      void prep_serialise();  //change last to count
  
      /*  Note that dump() and de_dump() are not required as calls to dump/de_dump a
        list class should be handled by a class derived from this.
  
        make_serialise is not required for a similar reason.
      */
  };
  
  /***********************************************************************
   *                          CLASS - ELIST_ITERATOR
   *
   *                          Generic iterator class for singly linked lists with embedded links
   **********************************************************************/
  
  class DLLSYM ELIST_ITERATOR
  {
    friend void ELIST::assign_to_sublist(ELIST_ITERATOR *, ELIST_ITERATOR *);
  
    ELIST *list;                   //List being iterated
    ELIST_LINK *prev;              //prev element
    ELIST_LINK *current;           //current element
    ELIST_LINK *next;              //next element
    BOOL8 ex_current_was_last;     //current extracted
    //was end of list
    BOOL8 ex_current_was_cycle_pt; //current extracted
    //was cycle point
    ELIST_LINK *cycle_pt;          //point we are cycling
    //the list to.
    BOOL8 started_cycling;         //Have we moved off
    //the start?
  
    ELIST_LINK *extract_sublist(                            //from this current...
                                ELIST_ITERATOR *other_it);  //to other current
  
    public:
      ELIST_ITERATOR() {  //constructor
        list = NULL;
      }                            //unassigned list
  
      ELIST_ITERATOR(  //constructor
                     ELIST *list_to_iterate);
  
      void set_to_list(  //change list
                       ELIST *list_to_iterate);
  
      void add_after_then_move(                        //add after current &
                               ELIST_LINK *new_link);  //move to new
  
      void add_after_stay_put(                        //add after current &
                              ELIST_LINK *new_link);  //stay at current
  
      void add_before_then_move(                        //add before current &
                                ELIST_LINK *new_link);  //move to new
  
      void add_before_stay_put(                        //add before current &
                               ELIST_LINK *new_link);  //stay at current
  
      void add_list_after(                      //add a list &
                          ELIST *list_to_add);  //stay at current
  
      void add_list_before(                      //add a list &
                           ELIST *list_to_add);  //move to it 1st item
  
      ELIST_LINK *data() {  //get current data
      #ifndef NDEBUG
        if (!list)
          NO_LIST.error ("ELIST_ITERATOR::data", ABORT, NULL);
        if (!current)
          NULL_DATA.error ("ELIST_ITERATOR::data", ABORT, NULL);
      #endif
        return current;
      }
  
      ELIST_LINK *data_relative(               //get data + or - ...
                                inT8 offset);  //offset from current
  
      ELIST_LINK *forward();  //move to next element
  
      ELIST_LINK *extract();  //remove from list
  
      ELIST_LINK *move_to_first();  //go to start of list
  
      ELIST_LINK *move_to_last();  //go to end of list
  
      void mark_cycle_pt();  //remember current
  
      BOOL8 empty() {  //is list empty?
      #ifndef NDEBUG
        if (!list)
          NO_LIST.error ("ELIST_ITERATOR::empty", ABORT, NULL);
      #endif
        return list->empty ();
      }
  
      BOOL8 current_extracted() {  //current extracted?
        return !current;
      }
  
      BOOL8 at_first();  //Current is first?
  
      BOOL8 at_last();  //Current is last?
  
      BOOL8 cycled_list();  //Completed a cycle?
  
      void add_to_end(                        //add at end &
                      ELIST_LINK *new_link);  //dont move
  
      void exchange(                            //positions of 2 links
                    ELIST_ITERATOR *other_it);  //other iterator
  
      inT32 length();  //# elements in list
  
      void sort (                  //sort elements
        int comparator (           //comparison routine
        const void *, const void *));
  
  };
  
  /***********************************************************************
   *                          ELIST_ITERATOR::set_to_list
   *
   *  (Re-)initialise the iterator to point to the start of the list_to_iterate
   *  over.
   **********************************************************************/
  
  inline void ELIST_ITERATOR::set_to_list(  //change list
                                          ELIST *list_to_iterate) {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::set_to_list", ABORT, NULL);
    if (!list_to_iterate)
      BAD_PARAMETER.error ("ELIST_ITERATOR::set_to_list", ABORT,
        "list_to_iterate is NULL");
    #endif
  
    list = list_to_iterate;
    prev = list->last;
    current = list->First ();
    next = current ? current->next : NULL;
    cycle_pt = NULL;               //await explicit set
    started_cycling = FALSE;
    ex_current_was_last = FALSE;
    ex_current_was_cycle_pt = FALSE;
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::ELIST_ITERATOR
   *
   *  CONSTRUCTOR - set iterator to specified list;
   **********************************************************************/
  
  inline ELIST_ITERATOR::ELIST_ITERATOR(ELIST *list_to_iterate) {
    set_to_list(list_to_iterate);
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::add_after_then_move
   *
   *  Add a new element to the list after the current element and move the
   *  iterator to the new element.
   **********************************************************************/
  
  inline void ELIST_ITERATOR::add_after_then_move(  // element to add
                                                  ELIST_LINK *new_element) {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::add_after_then_move", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::add_after_then_move", ABORT, NULL);
    if (!new_element)
      BAD_PARAMETER.error ("ELIST_ITERATOR::add_after_then_move", ABORT,
        "new_element is NULL");
    if (new_element->next)
      STILL_LINKED.error ("ELIST_ITERATOR::add_after_then_move", ABORT, NULL);
    #endif
  
    if (list->empty ()) {
      new_element->next = new_element;
      list->last = new_element;
      prev = next = new_element;
    }
    else {
      new_element->next = next;
  
      if (current) {               //not extracted
        current->next = new_element;
        prev = current;
        if (current == list->last)
          list->last = new_element;
      }
      else {                       //current extracted
        prev->next = new_element;
        if (ex_current_was_last)
          list->last = new_element;
        if (ex_current_was_cycle_pt)
          cycle_pt = new_element;
      }
    }
    current = new_element;
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::add_after_stay_put
   *
   *  Add a new element to the list after the current element but do not move
   *  the iterator to the new element.
   **********************************************************************/
  
  inline void ELIST_ITERATOR::add_after_stay_put(  // element to add
                                                 ELIST_LINK *new_element) {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::add_after_stay_put", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::add_after_stay_put", ABORT, NULL);
    if (!new_element)
      BAD_PARAMETER.error ("ELIST_ITERATOR::add_after_stay_put", ABORT,
        "new_element is NULL");
    if (new_element->next)
      STILL_LINKED.error ("ELIST_ITERATOR::add_after_stay_put", ABORT, NULL);
    #endif
  
    if (list->empty ()) {
      new_element->next = new_element;
      list->last = new_element;
      prev = next = new_element;
      ex_current_was_last = FALSE;
      current = NULL;
    }
    else {
      new_element->next = next;
  
      if (current) {               //not extracted
        current->next = new_element;
        if (prev == current)
          prev = new_element;
        if (current == list->last)
          list->last = new_element;
      }
      else {                       //current extracted
        prev->next = new_element;
        if (ex_current_was_last) {
          list->last = new_element;
          ex_current_was_last = FALSE;
        }
      }
      next = new_element;
    }
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::add_before_then_move
   *
   *  Add a new element to the list before the current element and move the
   *  iterator to the new element.
   **********************************************************************/
  
  inline void ELIST_ITERATOR::add_before_then_move(  // element to add
                                                   ELIST_LINK *new_element) {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::add_before_then_move", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::add_before_then_move", ABORT, NULL);
    if (!new_element)
      BAD_PARAMETER.error ("ELIST_ITERATOR::add_before_then_move", ABORT,
        "new_element is NULL");
    if (new_element->next)
      STILL_LINKED.error ("ELIST_ITERATOR::add_before_then_move", ABORT, NULL);
    #endif
  
    if (list->empty ()) {
      new_element->next = new_element;
      list->last = new_element;
      prev = next = new_element;
    }
    else {
      prev->next = new_element;
      if (current) {               //not extracted
        new_element->next = current;
        next = current;
      }
      else {                       //current extracted
        new_element->next = next;
        if (ex_current_was_last)
          list->last = new_element;
        if (ex_current_was_cycle_pt)
          cycle_pt = new_element;
      }
    }
    current = new_element;
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::add_before_stay_put
   *
   *  Add a new element to the list before the current element but dont move the
   *  iterator to the new element.
   **********************************************************************/
  
  inline void ELIST_ITERATOR::add_before_stay_put(  // element to add
                                                  ELIST_LINK *new_element) {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::add_before_stay_put", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::add_before_stay_put", ABORT, NULL);
    if (!new_element)
      BAD_PARAMETER.error ("ELIST_ITERATOR::add_before_stay_put", ABORT,
        "new_element is NULL");
    if (new_element->next)
      STILL_LINKED.error ("ELIST_ITERATOR::add_before_stay_put", ABORT, NULL);
    #endif
  
    if (list->empty ()) {
      new_element->next = new_element;
      list->last = new_element;
      prev = next = new_element;
      ex_current_was_last = TRUE;
      current = NULL;
    }
    else {
      prev->next = new_element;
      if (current) {               //not extracted
        new_element->next = current;
        if (next == current)
          next = new_element;
      }
      else {                       //current extracted
        new_element->next = next;
        if (ex_current_was_last)
          list->last = new_element;
      }
      prev = new_element;
    }
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::add_list_after
   *
   *  Insert another list to this list after the current element but dont move the
   *  iterator.
   **********************************************************************/
  
  inline void ELIST_ITERATOR::add_list_after(ELIST *list_to_add) {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::add_list_after", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::add_list_after", ABORT, NULL);
    if (!list_to_add)
      BAD_PARAMETER.error ("ELIST_ITERATOR::add_list_after", ABORT,
        "list_to_add is NULL");
    #endif
  
    if (!list_to_add->empty ()) {
      if (list->empty ()) {
        list->last = list_to_add->last;
        prev = list->last;
        next = list->First ();
        ex_current_was_last = TRUE;
        current = NULL;
      }
      else {
        if (current) {             //not extracted
          current->next = list_to_add->First ();
          if (current == list->last)
            list->last = list_to_add->last;
          list_to_add->last->next = next;
          next = current->next;
        }
        else {                     //current extracted
          prev->next = list_to_add->First ();
          if (ex_current_was_last) {
            list->last = list_to_add->last;
            ex_current_was_last = FALSE;
          }
          list_to_add->last->next = next;
          next = prev->next;
        }
      }
      list_to_add->last = NULL;
    }
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::add_list_before
   *
   *  Insert another list to this list before the current element. Move the
   *  iterator to the start of the inserted elements
   *  iterator.
   **********************************************************************/
  
  inline void ELIST_ITERATOR::add_list_before(ELIST *list_to_add) {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::add_list_before", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::add_list_before", ABORT, NULL);
    if (!list_to_add)
      BAD_PARAMETER.error ("ELIST_ITERATOR::add_list_before", ABORT,
        "list_to_add is NULL");
    #endif
  
    if (!list_to_add->empty ()) {
      if (list->empty ()) {
        list->last = list_to_add->last;
        prev = list->last;
        current = list->First ();
        next = current->next;
        ex_current_was_last = FALSE;
      }
      else {
        prev->next = list_to_add->First ();
        if (current) {             //not extracted
          list_to_add->last->next = current;
        }
        else {                     //current extracted
          list_to_add->last->next = next;
          if (ex_current_was_last)
            list->last = list_to_add->last;
          if (ex_current_was_cycle_pt)
            cycle_pt = prev->next;
        }
        current = prev->next;
        next = current->next;
      }
      list_to_add->last = NULL;
    }
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::extract
   *
   *  Do extraction by removing current from the list, returning it to the
   *  caller, but NOT updating the iterator.  (So that any calling loop can do
   *  this.)   The iterator's current points to NULL.  If the extracted element
   *  is to be deleted, this is the callers responsibility.
   **********************************************************************/
  
  inline ELIST_LINK *ELIST_ITERATOR::extract() {
    ELIST_LINK *extracted_link;
  
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::extract", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::extract", ABORT, NULL);
    if (!current)                  //list empty or
                                   //element extracted
      NULL_CURRENT.error ("ELIST_ITERATOR::extract",
        ABORT, NULL);
    #endif
  
    if (list->singleton()) {
      // Special case where we do need to change the iterator.
      prev = next = list->last = NULL;
    } else {
      prev->next = next;           //remove from list
  
      if (current == list->last) {
        list->last = prev;
        ex_current_was_last = TRUE;
      } else {
        ex_current_was_last = FALSE;
      }
    }
    // Always set ex_current_was_cycle_pt so an add/forward will work in a loop.
    ex_current_was_cycle_pt = (current == cycle_pt) ? TRUE : FALSE;
    extracted_link = current;
    extracted_link->next = NULL;   //for safety
    current = NULL;
    return extracted_link;
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::move_to_first()
   *
   *  Move current so that it is set to the start of the list.
   *  Return data just in case anyone wants it.
   **********************************************************************/
  
  inline ELIST_LINK *ELIST_ITERATOR::move_to_first() {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::move_to_first", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::move_to_first", ABORT, NULL);
    #endif
  
    current = list->First ();
    prev = list->last;
    next = current ? current->next : NULL;
    return current;
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::mark_cycle_pt()
   *
   *  Remember the current location so that we can tell whether we've returned
   *  to this point later.
   *
   *  If the current point is deleted either now, or in the future, the cycle
   *  point will be set to the next item which is set to current.  This could be
   *  by a forward, add_after_then_move or add_after_then_move.
   **********************************************************************/
  
  inline void ELIST_ITERATOR::mark_cycle_pt() {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::mark_cycle_pt", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::mark_cycle_pt", ABORT, NULL);
    #endif
  
    if (current)
      cycle_pt = current;
    else
      ex_current_was_cycle_pt = TRUE;
    started_cycling = FALSE;
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::at_first()
   *
   *  Are we at the start of the list?
   *
   **********************************************************************/
  
  inline BOOL8 ELIST_ITERATOR::at_first() {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::at_first", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::at_first", ABORT, NULL);
    #endif
  
                                   //we're at a deleted
    return ((list->empty ()) || (current == list->First ()) || ((current == NULL) &&
      (prev == list->last) &&      //NON-last pt between
      !ex_current_was_last));      //first and last
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::at_last()
   *
   *  Are we at the end of the list?
   *
   **********************************************************************/
  
  inline BOOL8 ELIST_ITERATOR::at_last() {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::at_last", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::at_last", ABORT, NULL);
    #endif
  
                                   //we're at a deleted
    return ((list->empty ()) || (current == list->last) || ((current == NULL) &&
      (prev == list->last) &&      //last point between
      ex_current_was_last));       //first and last
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::cycled_list()
   *
   *  Have we returned to the cycle_pt since it was set?
   *
   **********************************************************************/
  
  inline BOOL8 ELIST_ITERATOR::cycled_list() {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::cycled_list", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::cycled_list", ABORT, NULL);
    #endif
  
    return ((list->empty ()) || ((current == cycle_pt) && started_cycling));
  
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::length()
   *
   *  Return the length of the list
   *
   **********************************************************************/
  
  inline inT32 ELIST_ITERATOR::length() {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::length", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::length", ABORT, NULL);
    #endif
  
    return list->length ();
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::sort()
   *
   *  Sort the elements of the list, then reposition at the start.
   *
   **********************************************************************/
  
  inline void
  ELIST_ITERATOR::sort (           //sort elements
  int comparator (                 //comparison routine
  const void *, const void *)) {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::sort", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::sort", ABORT, NULL);
    #endif
  
    list->sort (comparator);
    move_to_first();
  }
  
  
  /***********************************************************************
   *                          ELIST_ITERATOR::add_to_end
   *
   *  Add a new element to the end of the list without moving the iterator.
   *  This is provided because a single linked list cannot move to the last as
   *  the iterator couldn't set its prev pointer.  Adding to the end is
   *  essential for implementing
                queues.
  **********************************************************************/
  
  inline void ELIST_ITERATOR::add_to_end(  // element to add
                                         ELIST_LINK *new_element) {
    #ifndef NDEBUG
    if (!this)
      NULL_OBJECT.error ("ELIST_ITERATOR::add_to_end", ABORT, NULL);
    if (!list)
      NO_LIST.error ("ELIST_ITERATOR::add_to_end", ABORT, NULL);
    if (!new_element)
      BAD_PARAMETER.error ("ELIST_ITERATOR::add_to_end", ABORT,
        "new_element is NULL");
    if (new_element->next)
      STILL_LINKED.error ("ELIST_ITERATOR::add_to_end", ABORT, NULL);
    #endif
  
    if (this->at_last ()) {
      this->add_after_stay_put (new_element);
    }
    else {
      if (this->at_first ()) {
        this->add_before_stay_put (new_element);
        list->last = new_element;
      }
      else {                       //Iteratr is elsewhere
        new_element->next = list->last->next;
        list->last->next = new_element;
        list->last = new_element;
      }
    }
  }
  
  
  /***********************************************************************
   ********************    MACROS    **************************************
   ***********************************************************************/
  
  /***********************************************************************
    QUOTE_IT   MACRO DEFINITION
    ===========================
  Replace <parm> with "<parm>".  <parm> may be an arbitrary number of tokens
  ***********************************************************************/
  
  #define QUOTE_IT( parm ) #parm
  
  /***********************************************************************
    ELISTIZE( CLASSNAME ) MACROS
    ============================
  
  CLASSNAME is assumed to be the name of a class which has a baseclass of
  ELIST_LINK.
  
  NOTE:  Because we dont use virtual functions in the list code, the list code
  will NOT work correctly for classes derived from this.
  
  The macros generate:
    - An element deletion function:      CLASSNAME##_zapper
    - An element serialiser function"    CLASSNAME##_serialiser
    - An element de-serialiser function" CLASSNAME##_de_serialiser
    - An E_LIST subclass: CLASSNAME##_LIST
    - An E_LIST_ITERATOR subclass:       CLASSNAME##_IT
  
  NOTE: Generated names are DELIBERATELY designed to clash with those for
  ELIST2IZE but NOT with those for CLISTIZE and CLIST2IZE
  
  Four macros are provided: ELISTIZE, ELISTIZE_S, ELISTIZEH and ELISTIZEH_S
  The ...IZEH macros just define the class names for use in .h files
  The ...IZE macros define the code use in .c files
  The _S versions define lists which can be serialised.  They assume that
  the make_serialise() macro is used in the list element class derived from
  ELIST_LINK to define serialise() and de_serialise() members for the list
  elements.
  ***********************************************************************/
  
  /***********************************************************************
    ELISTIZEH( CLASSNAME )  and  ELISTIZEH_S( CLASSNAME ) MACROS
  
  These macros are constructed from 3 fragments ELISTIZEH_A, ELISTIZEH_B and
  ELISTIZEH_C.  ELISTIZEH is simply a concatenation of these parts.
  ELISTIZEH_S has some additional bits thrown in the gaps.
  ***********************************************************************/
  
  #define ELISTIZEH_A(CLASSNAME)                                               \
                                                                               \
  extern DLLSYM void CLASSNAME##_zapper(ELIST_LINK* link);
  
  #define ELISTIZEH_B(CLASSNAME)                                               \
                                                                               \
  /***********************************************************************        \
  *                           CLASS - CLASSNAME##_LIST                                                                    \
  *                                                                                                       \
  *                           List class for class CLASSNAME                                                          \
  *                                                                                                       \
  **********************************************************************/         \
                                                                                                          \
  class DLLSYM                CLASSNAME##_LIST : public ELIST                         \
  {                                                                                                       \
  public:                                                                                             \
                              CLASSNAME##_LIST():ELIST() {}\
                                                          /* constructor */       \
                                                                                                          \
                              CLASSNAME##_LIST(           /* dont construct */ \
      const CLASSNAME##_LIST&)                            /*by initial assign*/\
      { DONT_CONSTRUCT_LIST_BY_COPY.error( QUOTE_IT( CLASSNAME##_LIST ),      \
                                                          ABORT, NULL ); }                            \
                                                                                                          \
  void                        clear()                     /* delete elements */\
      { ELIST::internal_clear( &CLASSNAME##_zapper ); }                               \
                                                                                                          \
                                      ~CLASSNAME##_LIST() /* destructor */        \
      { clear(); }                                                                                \
  \
  /* Become a deep copy of src_list*/ \
  void deep_copy(const CLASSNAME##_LIST* src_list, \
                 CLASSNAME* (*copier)(const CLASSNAME*)); \
  \
  void                        operator=(                  /* prevent assign */    \
      const CLASSNAME##_LIST&)                                                                \
      { DONT_ASSIGN_LISTS.error( QUOTE_IT( CLASSNAME##_LIST ),                        \
                                              ABORT, NULL ); }
  
  #define ELISTIZEH_C( CLASSNAME )                                                        \
  };                                                                                                      \
                                                                                                          \
                                                                                                          \
                                                                                                          \
  /***********************************************************************        \
  *                           CLASS - CLASSNAME##_IT                                                                      \
  *                                                                                                       \
  *                           Iterator class for class CLASSNAME##_LIST                                           \
  *                                                                                                       \
  *  Note: We don't need to coerce pointers to member functions input             \
  *  parameters as these are automatically converted to the type of the base      \
  *  type. ("A ptr to a class may be converted to a pointer to a public base      \
  *  class of that class")                                                                        \
  **********************************************************************/         \
                                                                                                          \
  class DLLSYM                CLASSNAME##_IT : public ELIST_ITERATOR                  \
  {                                                                                                       \
  public:                                                                                             \
                                  CLASSNAME##_IT():ELIST_ITERATOR(){}                     \
                                                                                                          \
                                  CLASSNAME##_IT(                                             \
  CLASSNAME##_LIST*           list):ELIST_ITERATOR(list){}                                \
                                                                                                          \
      CLASSNAME*          data()                                                          \
          { return (CLASSNAME*) ELIST_ITERATOR::data(); }                             \
                                                                                                          \
      CLASSNAME*          data_relative(                                                  \
      inT8                    offset)                                                         \
          { return (CLASSNAME*) ELIST_ITERATOR::data_relative( offset ); }        \
                                                                                                          \
      CLASSNAME*          forward()                                                       \
          { return (CLASSNAME*) ELIST_ITERATOR::forward(); }                          \
                                                                                                          \
      CLASSNAME*          extract()                                                       \
          { return (CLASSNAME*) ELIST_ITERATOR::extract(); }                          \
                                                                                                          \
      CLASSNAME*          move_to_first()                                             \
          { return (CLASSNAME*) ELIST_ITERATOR::move_to_first(); }                    \
                                                                                                          \
      CLASSNAME*          move_to_last()                                                  \
          { return (CLASSNAME*) ELIST_ITERATOR::move_to_last(); }                 \
  };
  
  #define ELISTIZEH( CLASSNAME )                                                      \
                                                                                                          \
  ELISTIZEH_A( CLASSNAME )                                                                        \
                                                                                                          \
  ELISTIZEH_B( CLASSNAME )                                                                        \
                                                                                                          \
  ELISTIZEH_C( CLASSNAME )
  
  #define ELISTIZEH_S( CLASSNAME )                                                        \
                                                                                                          \
  ELISTIZEH_A( CLASSNAME )                                                                        \
                                                                                                          \
  extern DLLSYM void          CLASSNAME##_serialiser(                                     \
  FILE*                       f,                                                                  \
  ELIST_LINK*                 element);                                                       \
                                                                                                          \
  extern DLLSYM ELIST_LINK*   CLASSNAME##_de_serialiser(                                  \
  FILE*                       f);                                                             \
                                                                                                          \
  ELISTIZEH_B( CLASSNAME )                                                                        \
                                                                                                          \
      void                    dump(                       /* dump to file */   \
      FILE*                   f)                                                                  \
      { ELIST::internal_dump( f, &CLASSNAME##_serialiser );}                      \
                                                                                                          \
      void                    de_dump(                    /* get from file */  \
      FILE*                   f)                                                                  \
      { ELIST::internal_de_dump( f, &CLASSNAME##_de_serialiser );}                \
                                                                                                          \
      void                    serialise_asc(              /*dump to ascii*/       \
      FILE*                   f);                                                                 \
      void                    de_serialise_asc(           /*de-dump from ascii*/\
      FILE*                   f);                                                                 \
                                                                                                          \
  make_serialise( CLASSNAME##_LIST )                                                  \
                                                                                                          \
  ELISTIZEH_C( CLASSNAME )
  
  /***********************************************************************
    ELISTIZE( CLASSNAME )  and   ELISTIZE_S( CLASSNAME )  MACROS
  ELISTIZE_S is a simple extension to ELISTIZE
  ***********************************************************************/
  
  #define ELISTIZE(CLASSNAME)                                                 \
                                                                              \
  /***********************************************************************    \
  *                           CLASSNAME##_zapper                              \
  *                                                                           \
  *  A function which can delete a CLASSNAME element.  This is passed to the  \
  *  generic clear list member function so that when a list is cleared the    \
  *  elements on the list are properly destroyed from the base class, even    \
  *  though we dont use a virtual destructor function.                        \
  **********************************************************************/     \
                                                                              \
  DLLSYM void CLASSNAME##_zapper(ELIST_LINK* link) {                          \
    delete reinterpret_cast<CLASSNAME*>(link);                                \
  }                                                                           \
                                                                              \
  /* Become a deep copy of src_list*/                                         \
  void CLASSNAME##_LIST::deep_copy(const CLASSNAME##_LIST* src_list,          \
                 CLASSNAME* (*copier)(const CLASSNAME*)) {                    \
                                                                              \
    CLASSNAME##_IT from_it(const_cast<CLASSNAME##_LIST*>(src_list));          \
    CLASSNAME##_IT to_it(this);                                               \
                                                                              \
    for (from_it.mark_cycle_pt(); !from_it.cycled_list(); from_it.forward())  \
      to_it.add_after_then_move((*copier)(from_it.data()));                   \
  }
  
  #define ELISTIZE_S(CLASSNAME)                                               \
                                                                              \
  ELISTIZE(CLASSNAME)                                                         \
                                                                              \
  void                  CLASSNAME##_LIST::serialise_asc(FILE* f) {            \
    CLASSNAME##_IT      it(this);                                             \
                                                                              \
    serialise_INT32(f, length());                                             \
    for (it.mark_cycle_pt(); !it.cycled_list(); it.forward())                 \
        it.data()->serialise_asc(f);                /*serialise the list*/    \
  }                                                                           \
                                                                              \
  void                  CLASSNAME##_LIST::de_serialise_asc(FILE* f) {         \
    inT32               len;                        /*length to retrive*/     \
    CLASSNAME##_IT      it;                                                   \
    CLASSNAME*          new_elt = NULL;               /*list element*/        \
                                                                              \
    len = de_serialise_INT32(f);                                              \
    it.set_to_list(this);                                                     \
    for (; len > 0; len--) {                                                  \
      new_elt = new CLASSNAME;                                                \
      new_elt->de_serialise_asc(f);                                           \
      it.add_to_end(new_elt);                     /*put on the list*/         \
    }                                                                         \
    return;                                                                   \
  }                                                                           \
                                                                              \
                                                                              \
  /***********************************************************************   \
  *                           CLASSNAME##_serialiser                         \
  *                                                                          \
  *  A function which can serialise an element                               \
  *  This is passed to the generic dump member function so that when a list is  \
  *  serialised the elements on the list are properly serialised.            \
  **********************************************************************/    \
                                                                             \
  DLLSYM void CLASSNAME##_serialiser(FILE* f, ELIST_LINK* element) {         \
    reinterpret_cast<CLASSNAME*>(element)->serialise(f);                     \
  }                                                                          \
                                                                             \
                                                                             \
                                                                             \
  /***********************************************************************   \
  *                           CLASSNAME##_de_serialiser                      \
  *                                                                          \
  *  A function which can de-serialise an element                            \
  *  This is passed to the generic de-dump member function so that when a list  \
  *  is de-serialised the elements on the list are properly de-serialised.   \
  **********************************************************************/    \
                                                                             \
  DLLSYM ELIST_LINK* CLASSNAME##_de_serialiser(FILE* f) {                  \
    return (ELIST_LINK*) CLASSNAME::de_serialise(f);                       \
  }
  #endif
  