prev->next = new_element;    }  list->prev = new_element;  new_element->next = list;  return new_element;  }DLList *dlink_insert_index(DLList *list, vpointer data, int index)  {  DLList *new_element;  DLList *this_list;    if (index < 0)    {/* FIXME: Prehaps I should insert from end of list instead? */    return dlink_append(list, data);    }  else if (index == 0)    {    return dlink_prepend(list, data);    }    this_list = dlink_nth(list, index);  if (!this_list)    return dlink_append(list, data);    new_element = dlink_new();  new_element->data = data;    if (this_list->prev)    {    this_list->prev->next = new_element;    new_element->prev = this_list->prev;    }  new_element->next = this_list;  this_list->prev = new_element;    if (this_list == list)    return new_element;  else    return list;  }DLList *dlink_delete_all_data(DLList *list, vpointer data)  {              DLList *tmp=list;   while (tmp)    {    if (tmp->data == data)      {      if (tmp->prev) tmp->prev->next = tmp->next;      if (tmp->next) tmp->next->prev = tmp->prev;      if (list == tmp) list = list->next;      dlink_free(tmp);      }    tmp = tmp->next;    }  return list;  }DLList *dlink_delete_data(DLList *list, vpointer data)  {  DLList *tmp=list;    while (tmp)    {    if (tmp->data == data)      {      if (tmp->prev) tmp->prev->next = tmp->next;      if (tmp->next) tmp->next->prev = tmp->prev;	        if (list == tmp) list = list->next;	        dlink_free(tmp);	        return list;      }    tmp = tmp->next;    }  return list;  }DLList *dlink_delete_link(DLList *list, DLList *link)  {  if (!link) return NULL;  if (link->prev) link->prev->next = link->next;  if (link->next) link->next->prev = link->prev;        if (link == list) list = list->next;        link->prev = NULL;  link->next = NULL;    return list;  }DLList *dlink_clone(DLList *list)  {  DLList *new_element = NULL;  DLList *last;  if (!list) return NULL;  new_element = dlink_new();  new_element->data = list->data;  last = new_element;  list = list->next;  while (list)    {    last->next = dlink_new();    last->next->prev = last;    last = last->next;    last->data = list->data;    list = list->next;    }  return new_element;  }DLList *dlink_reverse(DLList *list)  {  DLList *last=NULL;    while (list)    {    last = list;    list = last->next;    last->next = last->prev;    last->prev = list;    }    return last;  }DLList *dlink_nth(DLList *list, const int index)  {    int	i=index;  while (i > 0 && list)    {    list = list->next;    i--;    }    return list;  }DLList *dlink_pth(DLList *list, const int index)  {  int	i=index;  while (i > 0 && list)    {    list = list->prev;    i--;    }    return list;  }vpointer dlink_nth_data(DLList *list, const int index)  {  list = dlink_nth(list, index);    return list?list->data:NULL;  }vpointer dlink_pth_data(DLList *list, const int index)  {  list = dlink_pth(list, index);    return list?list->data:NULL;  }DLList *dlink_find(DLList *list, vpointer data)  {  while (list && list->data != data)    list = list->next;    return list;  }DLList *dlink_find_custom(DLList *list, vpointer data, LLCompareFunc func)  {  if (!func) die("Null pointer to LLCompareFunc passed.");  while (list && func(list->data, data)==FALSE)    list = list->next;  return list;  }int dlink_index_link(DLList *list, DLList *link)  {  int i=0;  while (list)    {    if (list == link) return i;    i++;    list = list->next;    }  return -1;  }int dlink_index_data(DLList *list, vpointer data)  {  int i=0;  while (list)    {    if (list->data == data) return i;    i++;    list = list->next;    }  return -1;  }DLList *dlink_last(DLList *list)  {  if (!list) return NULL;  while (list->next)    list = list->next;    return list;  }DLList *dlink_first(DLList *list)  {  if (!list) return NULL;  while (list->prev) list = list->prev;    return list;  }int dlink_size(DLList *list)  {  int	size=0;    while (list)    {    size++;    list = list->next;    }    return size;  }boolean dlink_foreach(DLList *list, LLForeachFunc func, vpointer userdata)  {  if (!func) die("Null pointer to LLForeachFunc passed.");  while (list)    {    if ((*func)(list->data, userdata)) return TRUE;    list = list->next;    }  return FALSE;  }boolean dlink_foreach_reverse(DLList *list, LLForeachFunc func, vpointer userdata)  {  if (!func) die("Null pointer to LLForeachFunc passed.");  while (list)    {    if ((*func)(list->data, userdata)) return TRUE;    list = list->prev;    }  return FALSE;  }DLList *dlink_insert_sorted(DLList *list, vpointer data, LLCompareFunc func)  {  DLList *this_list;  DLList *prev_list;  DLList *new_element;  if (!func) die("Null pointer to LLCompareFunc passed.");  new_element = dlink_new();  new_element->data = data;  if (!list) return new_element;  this_list = list;  prev_list = NULL;  while (this_list && func(this_list->data, data)<0)    {    prev_list = this_list;    this_list = this_list->next;    }  new_element->prev = prev_list;  new_element->next = this_list;  if (this_list)    {    this_list->prev = new_element;    if (!prev_list) return new_element;    }  prev_list->next = new_element;  return list;  }/* * Testing: */void linkedlist_diagnostics(void)  {  printf("=== Linked list diagnostics ==================================\n");  printf("Version:                   %s\n", GA_VERSION_STRING);  printf("Build date:                %s\n", GA_BUILD_DATE_STRING);  printf("Compilation machine characteristics:\n%s\n", GA_UNAME_STRING);  printf("--------------------------------------------------------------\n");  printf("structure          sizeof\n");  printf("SLList             %lu\n", (unsigned long) sizeof(SLList));  printf("DLList             %lu\n", (unsigned long) sizeof(DLList));  printf("==============================================================\n");  return;  }static boolean test_list_print(vpointer a, vpointer b)  {  int val = *((int*)a);  printf("%d ", val);  return FALSE;  }static int test_list_compare_one(constvpointer a, constvpointer b)  {  int one = *((const int*)a);  int two = *((const int*)b);  return one-two;  }static int test_list_compare_two(constvpointer a, constvpointer b)  {  int one = *((const int*)a);  int two = *((const int*)b);  return two-one;  }/* * This function is 'borrowed' from glib. * This shows that the glib-emulation works. */#ifdef LINKEDLIST_COMPILE_MAINint main(int argc, char **argv)#elseboolean linkedlist_test(void)#endif#ifdef LINKEDLIST_EMULATE_GLIST  {  DLList *list, *t;  SLList *slist, *st;  int sorteddata[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };  int data[10] = { 8, 9, 7, 0, 3, 2, 5, 1, 4, 6 };  int i;  printf("Checking doubly linked lists...\n");  list = NULL;  for (i = 0; i < 10; i++)    list = g_list_append(list, &sorteddata[i]);  list = g_list_reverse(list);  for (i = 0; i < 10; i++)    {      t = g_list_nth (list, i);      if (*((int*) t->data) != (9 - i))	printf("Regular insert failed\n");    }  for (i = 0; i < 10; i++)    if(g_list_position(list, g_list_nth (list, i)) != i)      printf("g_list_position does not seem to be the inverse of g_list_nth\n");  g_list_free(list);  list = NULL;  for (i = 0; i < 10; i++)    list = g_list_insert_sorted(list, &data[i], test_list_compare_one);  g_list_foreach(list, test_list_print, NULL);  printf("\n");  for (i = 0; i < 10; i++)    {      t = g_list_nth(list, i);      if (*((int*) t->data) != i)         printf("Sorted insert failed\n");    }  g_list_free(list);  list = NULL;  for (i = 0; i < 10; i++)    list = g_list_insert_sorted(list, &data[i], test_list_compare_two);  g_list_foreach(list, test_list_print, NULL);  printf("\n");  for (i = 0; i < 10; i++)    {      t = g_list_nth(list, i);      if (*((int*) t->data) != (9 - i))         printf("Sorted insert failed\n");    }  g_list_free(list);  printf ("ok\n");  printf ("Checking singly linked lists...\n");  slist = NULL;  for (i = 0; i < 10; i++)    slist = g_slist_append(slist, &sorteddata[i]);  slist = g_slist_reverse(slist);  for (i = 0; i < 10; i++)    {      st = g_slist_nth(slist, i);      if (*((int*) st->data) != (9 - i))	printf ("failed\n");    }  g_slist_free(slist);  slist = NULL;  for (i = 0; i < 10; i++)    slist = g_slist_insert_sorted(slist, &data[i], test_list_compare_one);  g_slist_foreach(slist, test_list_print, NULL);  printf("\n");  for (i = 0; i < 10; i++)    {      st = g_slist_nth (slist, i);      if (*((int*) st->data) != i)         printf ("Sorted insert failed\n");    }  g_slist_free(slist);  slist = NULL;  for (i = 0; i < 10; i++)    slist = g_slist_insert_sorted(slist, &data[i], test_list_compare_two);  g_slist_foreach(slist, test_list_print, NULL);  printf("\n");  for (i = 0; i < 10; i++)    {      st = g_slist_nth(slist, i);      if (*((int*) st->data) != (9 - i))         printf("Sorted insert failed\n");    }  g_slist_free(slist);  printf("ok\n");#else  {  DLList *list, *t;  SLList *slist, *st;  int sorteddata[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };  int data[10] = { 8, 9, 7, 0, 3, 2, 5, 1, 4, 6 };  int i;  printf("Checking doubly linked lists...\n");  list = NULL;  for (i = 0; i < 10; i++)    list = dlink_append(list, &sorteddata[i]);  list = dlink_reverse(list);  for (i = 0; i < 10; i++)    {      t = dlink_nth(list, i);      if (*((int*) t->data) != (9 - i))	printf("Regular insert failed\n");    }  for (i = 0; i < 10; i++)    if(dlink_index_link(list, dlink_nth(list, i)) != (int) i)      printf("dlink_index_link does not seem to be the inverse of dlink_nth_data\n");  dlink_free_all(list);  list = NULL;  for (i = 0; i < 10; i++)    list = dlink_insert_sorted(list, &data[i], test_list_compare_one);  dlink_foreach(list, test_list_print, NULL);  printf("\n");  for (i = 0; i < 10; i++)    {      t = dlink_nth(list, i);      if (*((int*) t->data) != i)         printf("Sorted insert failed\n");    }  dlink_free_all(list);  list = NULL;  for (i = 0; i < 10; i++)    list = dlink_insert_sorted(list, &data[i], test_list_compare_two);  dlink_foreach(list, test_list_print, NULL);  printf("\n");  for (i = 0; i < 10; i++)    {      t = dlink_nth(list, i);      if (*((int*) t->data) != (9 - i))         printf("Sorted insert failed\n");    }  dlink_free_all(list);  printf ("ok\n");  printf ("Checking singly linked lists...\n");  slist = NULL;  for (i = 0; i < 10; i++)    slist = slink_append(slist, &sorteddata[i]);  slist = slink_reverse(slist);  for (i = 0; i < 10; i++)    {      st = slink_nth(slist, i);      if (*((int*) st->data) != (9 - i))	printf ("failed\n");    }  slink_free_all(slist);  slist = NULL;  for (i = 0; i < 10; i++)    slist = slink_insert_sorted(slist, &data[i], test_list_compare_one);  slink_foreach(slist, test_list_print, NULL);  printf("\n");  for (i = 0; i < 10; i++)    {      st = slink_nth(slist, i);      if (*((int*) st->data) != (int) i)         printf ("Sorted insert failed\n");    }  slink_free_all(slist);  slist = NULL;  for (i = 0; i < 10; i++)    slist = slink_insert_sorted(slist, &data[i], test_list_compare_two);  slink_foreach(slist, test_list_print, NULL);  printf("\n");  for (i = 0; i < 10; i++)    {      st = slink_nth(slist, i);      if (*((int*) st->data) != (9 - i))         printf("Sorted insert failed\n");    }  slink_free_all(slist);  printf("ok\n");#endif#ifdef LINKEDLIST_COMPILE_MAIN  exit(EXIT_SUCCESS);#else  return TRUE;#endif  }