/* GLIB - Library of useful routines for C programming

 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 02111-1307, USA.

 */

/*

 * Modified by the GLib Team and others 1997-2000.  See the AUTHORS

 * file for a list of people on the GLib Team.  See the ChangeLog

 * files for a list of changes.  These files are distributed with

 * GLib at ftp://ftp.gtk.org/pub/gtk/.

 */

/*

 * MT safe

 */

#include "config.h"

#include "glist.h"

#include "gslice.h"

#include "gtestutils.h"

/**

 * SECTION:linked_lists_double

 * @title: Doubly-Linked Lists

 * @short_description: linked lists that can be iterated over in both directions

 *

 * The #GList structure and its associated functions provide a standard

 * doubly-linked list data structure.

 *

 * Each element in the list contains a piece of data, together with

 * pointers which link to the previous and next elements in the list.

 * Using these pointers it is possible to move through the list in both

 * directions (unlike the 

 * linkend="glib-Singly-Linked-Lists">Singly-Linked Lists</link> which

 * only allows movement through the list in the forward direction).

 *

 * The data contained in each element can be either integer values, by

 * using one of the <link linkend="glib-Type-Conversion-Macros">Type

 * Conversion Macros</link>, or simply pointers to any type of data.

 *

 * List elements are allocated from the 

 * linkend="glib-Memory-Slices">slice allocator</link>, which is more

 * efficient than allocating elements individually.

 *

 * Note that most of the #GList functions expect to be passed a pointer

 * to the first element in the list. The functions which insert

 * elements return the new start of the list, which may have changed.

 *

 * There is no function to create a #GList. %NULL is considered to be

 * the empty list so you simply set a #GList* to %NULL.

 *

 * To add elements, use g_list_append(), g_list_prepend(),

 * g_list_insert() and g_list_insert_sorted().

 *

 * To remove elements, use g_list_remove().

 *

 * To find elements in the list use g_list_first(), g_list_last(),

 * g_list_next(), g_list_previous(), g_list_nth(), g_list_nth_data(),

 * g_list_find() and g_list_find_custom().

 *

 * To find the index of an element use g_list_position() and

 * g_list_index().

 *

 * To call a function for each element in the list use g_list_foreach().

 *

 * To free the entire list, use g_list_free().

 **/

/**

 * GList:

 * @data: holds the element's data, which can be a pointer to any kind

 *        of data, or any integer value using the 

 *        linkend="glib-Type-Conversion-Macros">Type Conversion

 *        Macros</link>.

 * @next: contains the link to the next element in the list.

 * @prev: contains the link to the previous element in the list.

 *

 * The #GList struct is used for each element in a doubly-linked list.

 **/

/**

 * g_list_previous:

 * @list: an element in a #GList.

 * @Returns: the previous element, or %NULL if there are no previous

 *           elements.

 *

 * A convenience macro to get the previous element in a #GList.

 **/

/**

 * g_list_next:

 * @list: an element in a #GList.

 * @Returns: the next element, or %NULL if there are no more elements.

 *

 * A convenience macro to get the next element in a #GList.

 **/

#define _g_list_alloc()         g_slice_new (GList)

#define _g_list_alloc0()        g_slice_new0 (GList)

#define _g_list_free1(list)     g_slice_free (GList, list)

/**

 * g_list_alloc:

 * @Returns: a pointer to the newly-allocated #GList element.

 *

 * Allocates space for one #GList element. It is called by

 * g_list_append(), g_list_prepend(), g_list_insert() and

 * g_list_insert_sorted() and so is rarely used on its own.

 **/

GList*

g_list_alloc (void)

{

  return _g_list_alloc0 ();

}

/**

 * g_list_free: 

 * @list: a #GList

 *

 * Frees all of the memory used by a #GList.

 * The freed elements are returned to the slice allocator.

 *

 * <note><para>

 * If list elements contain dynamically-allocated memory, 

 * you should either use g_list_free_full() or free them manually

 * first.

 * </para></note>

 */

void

g_list_free (GList *list)

{

  g_slice_free_chain (GList, list, next);

}

/**

 * g_list_free_1:

 * @list: a #GList element

 *

 * Frees one #GList element.

 * It is usually used after g_list_remove_link().

 */

/**

 * g_list_free1:

 *

 * Another name for g_list_free_1().

 **/

void

g_list_free_1 (GList *list)

{

  _g_list_free1 (list);

}

/**

 * g_list_free_full:

 * @list: a pointer to a #GList

 * @free_func: the function to be called to free each element's data

 *

 * Convenience method, which frees all the memory used by a #GList, and

 * calls the specified destroy function on every element's data.

 *

 * Since: 2.28

 */

void

g_list_free_full (GList          *list,

		  GDestroyNotify  free_func)

{

  g_list_foreach (list, (GFunc) free_func, NULL);

  g_list_free (list);

}

/**

 * g_list_append:

 * @list: a pointer to a #GList

 * @data: the data for the new element

 *

 * Adds a new element on to the end of the list.

 *

 * <note><para>

 * The return value is the new start of the list, which 

 * may have changed, so make sure you store the new value.

 * </para></note>

 *

 * <note><para>

 * Note that g_list_append() has to traverse the entire list 

 * to find the end, which is inefficient when adding multiple 

 * elements. A common idiom to avoid the inefficiency is to prepend 

 * the elements and reverse the list when all elements have been added.

 * </para></note>

 *

 * |[

 * /* Notice that these are initialized to the empty list. */

 * GList *list = NULL, *number_list = NULL;

 *

 * /* This is a list of strings. */

 * list = g_list_append (list, "first");

 * list = g_list_append (list, "second");

 * 

 * /* This is a list of integers. */

 * number_list = g_list_append (number_list, GINT_TO_POINTER (27));

 * number_list = g_list_append (number_list, GINT_TO_POINTER (14));

 * ]|

 *

 * Returns: the new start of the #GList

 */

GList*

g_list_append (GList	*list,

	       gpointer	 data)

{

  GList *new_list;

  GList *last;

  new_list = _g_list_alloc ();

  new_list->data = data;

  new_list->next = NULL;

  if (list)

    {

      last = g_list_last (list);

      /* g_assert (last != NULL); */

      last->next = new_list;

      new_list->prev = last;

      return list;

    }

  else

    {

      new_list->prev = NULL;

      return new_list;

    }

}

/**

 * g_list_prepend:

 * @list: a pointer to a #GList

 * @data: the data for the new element

 *

 * Adds a new element on to the start of the list.

 *

 * <note><para>

 * The return value is the new start of the list, which 

 * may have changed, so make sure you store the new value.

 * </para></note>

 *

 * |[ 

 * /* Notice that it is initialized to the empty list. */

 * GList *list = NULL;

 * list = g_list_prepend (list, "last");

 * list = g_list_prepend (list, "first");

 * ]|

 *

 * Returns: the new start of the #GList

 */

GList*

g_list_prepend (GList	 *list,

		gpointer  data)

{

  GList *new_list;

  new_list = _g_list_alloc ();

  new_list->data = data;

  new_list->next = list;

  if (list)

    {

      new_list->prev = list->prev;

      if (list->prev)

	list->prev->next = new_list;

      list->prev = new_list;

    }

  else

    new_list->prev = NULL;

  return new_list;

}

/**

 * g_list_insert:

 * @list: a pointer to a #GList

 * @data: the data for the new element

 * @position: the position to insert the element. If this is 

 *     negative, or is larger than the number of elements in the 

 *     list, the new element is added on to the end of the list.

 * 

 * Inserts a new element into the list at the given position.

 *

 * Returns: the new start of the #GList

 */

GList*

g_list_insert (GList	*list,

	       gpointer	 data,

	       gint	 position)

{

  GList *new_list;

  GList *tmp_list;

  if (position < 0)

    return g_list_append (list, data);

  else if (position == 0)

    return g_list_prepend (list, data);

  tmp_list = g_list_nth (list, position);

  if (!tmp_list)

    return g_list_append (list, data);

  new_list = _g_list_alloc ();

  new_list->data = data;

  new_list->prev = tmp_list->prev;

  tmp_list->prev->next = new_list;

  new_list->next = tmp_list;

  tmp_list->prev = new_list;

  return list;

}

/**

 * g_list_insert_before:

 * @list: a pointer to a #GList

 * @sibling: the list element before which the new element 

 *     is inserted or %NULL to insert at the end of the list

 * @data: the data for the new element

 *

 * Inserts a new element into the list before the given position.

 *

 * Returns: the new start of the #GList

 */

GList*

g_list_insert_before (GList   *list,

		      GList   *sibling,

		      gpointer data)

{

  if (!list)

    {

      list = g_list_alloc ();

      list->data = data;

      g_return_val_if_fail (sibling == NULL, list);

      return list;

    }

  else if (sibling)

    {

      GList *node;

      node = _g_list_alloc ();

      node->data = data;

      node->prev = sibling->prev;

      node->next = sibling;

      sibling->prev = node;

      if (node->prev)

	{

	  node->prev->next = node;

	  return list;

	}

      else

	{

	  g_return_val_if_fail (sibling == list, node);

	  return node;

	}

    }

  else

    {

      GList *last;

      last = list;

      while (last->next)

	last = last->next;

      last->next = _g_list_alloc ();

      last->next->data = data;

      last->next->prev = last;

      last->next->next = NULL;

      return list;

    }

}

/**

 * g_list_concat:

 * @list1: a #GList

 * @list2: the #GList to add to the end of the first #GList

 *

 * Adds the second #GList onto the end of the first #GList.

 * Note that the elements of the second #GList are not copied.

 * They are used directly.

 *

 * Returns: the start of the new #GList

 */

GList *

g_list_concat (GList *list1, GList *list2)

{

  GList *tmp_list;

  if (list2)

    {

      tmp_list = g_list_last (list1);

      if (tmp_list)

	tmp_list->next = list2;

      else

	list1 = list2;

      list2->prev = tmp_list;

    }

  return list1;

}

/**

 * g_list_remove:

 * @list: a #GList

 * @data: the data of the element to remove

 *

 * Removes an element from a #GList.

 * If two elements contain the same data, only the first is removed.

 * If none of the elements contain the data, the #GList is unchanged.

 *

 * Returns: the new start of the #GList

 */

GList*

g_list_remove (GList	     *list,

	       gconstpointer  data)

{

  GList *tmp;

  tmp = list;

  while (tmp)

    {

      if (tmp->data != data)

	tmp = tmp->next;

      else

	{

	  if (tmp->prev)

	    tmp->prev->next = tmp->next;

	  if (tmp->next)

	    tmp->next->prev = tmp->prev;

	  if (list == tmp)

	    list = list->next;

	  _g_list_free1 (tmp);

	  break;

	}

    }

  return list;

}

/**

 * g_list_remove_all:

 * @list: a #GList

 * @data: data to remove

 *

 * Removes all list nodes with data equal to @data. 

 * Returns the new head of the list. Contrast with 

 * g_list_remove() which removes only the first node 

 * matching the given data.

 *

 * Returns: new head of @list

 */

GList*

g_list_remove_all (GList	*list,

		   gconstpointer data)

{

  GList *tmp = list;

  while (tmp)

    {

      if (tmp->data != data)

	tmp = tmp->next;

      else

	{

	  GList *next = tmp->next;

	  if (tmp->prev)

	    tmp->prev->next = next;

	  else

	    list = next;

	  if (next)

	    next->prev = tmp->prev;

	  _g_list_free1 (tmp);

	  tmp = next;

	}

    }

  return list;

}

static inline GList*

_g_list_remove_link (GList *list,

		     GList *link)

{

  if (link)

    {

      if (link->prev)

	link->prev->next = link->next;

      if (link->next)

	link->next->prev = link->prev;

      if (link == list)

	list = list->next;

      link->next = NULL;

      link->prev = NULL;

    }

  return list;

}

/**

 * g_list_remove_link:

 * @list: a #GList

 * @llink: an element in the #GList

 *

 * Removes an element from a #GList, without freeing the element.

 * The removed element's prev and next links are set to %NULL, so 

 * that it becomes a self-contained list with one element.

 *

 * Returns: the new start of the #GList, without the element

 */

GList*

g_list_remove_link (GList *list,

		    GList *llink)

{

  return _g_list_remove_link (list, llink);

}

/**

 * g_list_delete_link:

 * @list: a #GList

 * @link_: node to delete from @list

 *

 * Removes the node link_ from the list and frees it. 

 * Compare this to g_list_remove_link() which removes the node 

 * without freeing it.

 *

 * Returns: the new head of @list

 */

GList*

g_list_delete_link (GList *list,

		    GList *link_)

{

  list = _g_list_remove_link (list, link_);

  _g_list_free1 (link_);

  return list;

}

/**

 * g_list_copy:

 * @list: a #GList

 *

 * Copies a #GList.

 *

 * <note><para>

 * Note that this is a "shallow" copy. If the list elements 

 * consist of pointers to data, the pointers are copied but 

 * the actual data is not.

 * </para></note>

 *

 * Returns: a copy of @list

 */

GList*

g_list_copy (GList *list)

{

  GList *new_list = NULL;

  if (list)

    {

      GList *last;

      new_list = _g_list_alloc ();

      new_list->data = list->data;

      new_list->prev = NULL;

      last = new_list;

      list = list->next;

      while (list)

	{

	  last->next = _g_list_alloc ();

	  last->next->prev = last;

	  last = last->next;

	  last->data = list->data;

	  list = list->next;

	}

      last->next = NULL;

    }

  return new_list;

}

/**

 * g_list_reverse:

 * @list: a #GList

 *

 * Reverses a #GList.

 * It simply switches the next and prev pointers of each element.

 *

 * Returns: the start of the reversed #GList

 */

GList*

g_list_reverse (GList *list)

{

  GList *last;

  last = NULL;

  while (list)

    {

      last = list;

      list = last->next;

      last->next = last->prev;

      last->prev = list;

    }

  return last;

}

/**

 * g_list_nth:

 * @list: a #GList

 * @n: the position of the element, counting from 0

 *

 * Gets the element at the given position in a #GList.

 *

 * Returns: the element, or %NULL if the position is off 

 *     the end of the #GList

 */

GList*

g_list_nth (GList *list,

	    guint  n)

{

  while ((n-- > 0) && list)

    list = list->next;

  return list;

}

/**

 * g_list_nth_prev:

 * @list: a #GList

 * @n: the position of the element, counting from 0

 *

 * Gets the element @n places before @list.

 *

 * Returns: the element, or %NULL if the position is 

 *     off the end of the #GList

 */

GList*

g_list_nth_prev (GList *list,

		 guint  n)

{

  while ((n-- > 0) && list)

    list = list->prev;

  return list;

}

/**

 * g_list_nth_data:

 * @list: a #GList

 * @n: the position of the element

 *

 * Gets the data of the element at the given position.

 *

 * Returns: the element's data, or %NULL if the position 

 *     is off the end of the #GList

 */

gpointer

g_list_nth_data (GList     *list,

		 guint      n)

{

  while ((n-- > 0) && list)

    list = list->next;

  return list ? list->data : NULL;

}

/**

 * g_list_find:

 * @list: a #GList

 * @data: the element data to find

 *

 * Finds the element in a #GList which 

 * contains the given data.

 *

 * Returns: the found #GList element, 

 *     or %NULL if it is not found

 */

GList*

g_list_find (GList         *list,

	     gconstpointer  data)

{

  while (list)

    {

      if (list->data == data)

	break;

      list = list->next;

    }

  return list;

}

/**

 * g_list_find_custom:

 * @list: a #GList

 * @data: user data passed to the function

 * @func: the function to call for each element. 

 *     It should return 0 when the desired element is found

 *

 * Finds an element in a #GList, using a supplied function to 

 * find the desired element. It iterates over the list, calling 

 * the given function which should return 0 when the desired 

 * element is found. The function takes two #gconstpointer arguments, 

 * the #GList element's data as the first argument and the 

 * given user data.

 *

 * Returns: the found #GList element, or %NULL if it is not found

 */

GList*

g_list_find_custom (GList         *list,

		    gconstpointer  data,

		    GCompareFunc   func)

{

  g_return_val_if_fail (func != NULL, list);

  while (list)

    {

      if (! func (list->data, data))

	return list;

      list = list->next;

    }

  return NULL;

}

/**

 * g_list_position:

 * @list: a #GList

 * @llink: an element in the #GList

 *

 * Gets the position of the given element 

 * in the #GList (starting from 0).

 *

 * Returns: the position of the element in the #GList, 

 *     or -1 if the element is not found

 */

gint

g_list_position (GList *list,

		 GList *llink)

{

  gint i;

  i = 0;

  while (list)

    {

      if (list == llink)

	return i;

      i++;

      list = list->next;

    }

  return -1;

}

/**

 * g_list_index:

 * @list: a #GList

 * @data: the data to find

 *

 * Gets the position of the element containing 

 * the given data (starting from 0).

 *

 * Returns: the index of the element containing the data, 

 *     or -1 if the data is not found

 */

gint

g_list_index (GList         *list,

	      gconstpointer  data)

{

  gint i;

  i = 0;

  while (list)

    {

      if (list->data == data)

	return i;

      i++;

      list = list->next;

    }

  return -1;

}

/**

 * g_list_last:

 * @list: a #GList

 *

 * Gets the last element in a #GList.

 *

 * Returns: the last element in the #GList, 

 *     or %NULL if the #GList has no elements

 */

GList*

g_list_last (GList *list)

{

  if (list)

    {

      while (list->next)

	list = list->next;

    }

  return list;

}

/**

 * g_list_first:

 * @list: a #GList

 *

 * Gets the first element in a #GList.

 *

 * Returns: the first element in the #GList, 

 *     or %NULL if the #GList has no elements

 */

GList*

g_list_first (GList *list)

{

  if (list)

    {

      while (list->prev)

	list = list->prev;

    }

  return list;

}

/**

 * g_list_length:

 * @list: a #GList

 *

 * Gets the number of elements in a #GList.

 *

 * <note><para>

 * This function iterates over the whole list to 

 * count its elements.

 * </para></note>

 *

 * Returns: the number of elements in the #GList

 */

guint

g_list_length (GList *list)

{

  guint length;

  length = 0;

  while (list)

    {

      length++;

      list = list->next;

    }

  return length;

}

/**

 * g_list_foreach:

 * @list: a #GList

 * @func: the function to call with each element's data

 * @user_data: user data to pass to the function

 *