/*
 * Copyright (c) 2007 Daniel Borca  All rights reserved.
 *
 * 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 program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */


#ifndef LIST_H_included
#define LIST_H_included

/**
 * Remove an element from list.
 *
 * \param elem element to remove.
 */
#define list_remove(elem)			\
do {						\
    (elem)->next->prev = (elem)->prev;		\
    (elem)->prev->next = (elem)->next;		\
} while (0)

/**
 * Insert an element to the list head.
 *
 * \param list list.
 * \param elem element to insert.
 */
#define list_prepend(list, elem)		\
do {						\
    (elem)->prev = list;			\
    (elem)->next = (list)->next;		\
    (list)->next->prev = elem;			\
    (list)->next = elem;			\
} while(0)

/**
 * Insert an element to the list tail.
 *
 * \param list list.
 * \param elem element to insert.
 */
#define list_append(list, elem)			\
do {						\
    (elem)->next = list;			\
    (elem)->prev = (list)->prev;		\
    (list)->prev->next = elem;			\
    (list)->prev = elem;			\
} while(0)

/**
 * Make a empty list empty.
 *
 * \param sentinel list (sentinel element).
 */
#define list_create(sentinel)			\
do {						\
    (sentinel)->next = sentinel;		\
    (sentinel)->prev = sentinel;		\
} while (0)

/**
 * Get list first element.
 *
 * \param list list.
 *
 * \return pointer to first element.
 */
#define list_first(list)	((list)->next)

/**
 * Get list last element.
 *
 * \param list list.
 *
 * \return pointer to last element.
 */
#define list_last(list)		((list)->prev)

/**
 * Get next element.
 *
 * \param elem element.
 *
 * \return pointer to next element.
 */
#define list_next(elem)		((elem)->next)

/**
 * Get previous element.
 *
 * \param elem element.
 *
 * \return pointer to previous element.
 */
#define list_prev(elem)		((elem)->prev)

/**
 * Test whether element is at end of the list.
 *
 * \param list list.
 * \param elem element.
 *
 * \return non-zero if element is at end of list, or zero otherwise.
 */
#define list_at_end(list, elem)	((elem) == (list))

/**
 * Test if a list is empty.
 *
 * \param list list.
 *
 * \return non-zero if list empty, or zero otherwise.
 */
#define list_is_empty(list)	((list)->next == (list))

/**
 * Walk through the elements of a list.
 *
 * \param ptr pointer to the current element.
 * \param list list.
 *
 * \note It should be followed by a { } block or a single statement, as in a \c
 * for loop.
 */
#define list_foreach(ptr, list)\
    for (ptr = (list)->next; ptr != list;  ptr = (ptr)->next)

/**
 * Walk through the elements of a list.
 *
 * Same as #foreach but lets you unlink the current value during a list
 * traversal.  Useful for freeing a list, element by element.
 *
 * \param ptr pointer to the current element.
 * \param t temporary pointer.
 * \param list list.
 *
 * \note It should be followed by a { } block or a single statement, as in a \c
 * for loop.
 */
#define list_foreach_s(ptr, t, list)\
    for (ptr = (list)->next, t = (ptr)->next; list != ptr; ptr = t, t = (t)->next)

#endif