/**
* \file simple_list.h
* Simple macros for type-safe, intrusive lists.
*
* Intended to work with a list sentinal which is created as an empty
* list. Insert & delete are O(1).
*
* \author
* (C) 1997, Keith Whitwell
*/
/*
* Mesa 3-D graphics library
*
* Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef _U_SIMPLE_LIST_H_
#define _U_SIMPLE_LIST_H_
/**
* Remove an element from list.
*
* \param elem element to remove.
*/
#define remove_from_list(elem) \
do { \
(elem)->next->prev = (elem)->prev; \
(elem)->prev->next = (elem)->next; \
(elem)->next = elem; \
(elem)->prev = elem; \
} while (0)
/**
* Insert an element to the list head.
*
* \param list list.
* \param elem element to insert.
*/
#define insert_at_head(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 insert_at_tail(list, elem) \
do { \
(elem)->next = list; \
(elem)->prev = (list)->prev; \
(list)->prev->next = elem; \
(list)->prev = elem; \
} while(0)
/**
* Move an element to the list head.
*
* \param list list.
* \param elem element to move.
*/
#define move_to_head(list, elem) \
do { \
remove_from_list(elem); \
insert_at_head(list, elem); \
} while (0)
/**
* Move an element to the list tail.
*
* \param list list.
* \param elem element to move.
*/
#define move_to_tail(list, elem) \
do { \
remove_from_list(elem); \
insert_at_tail(list, elem); \
} while (0)
/**
* Make a empty list empty.
*
* \param sentinal list (sentinal element).
*/
#define make_empty_list(sentinal) \
do { \
(sentinal)->next = sentinal; \
(sentinal)->prev = sentinal; \
} while (0)
/**
* Get list first element.
*
* \param list list.
*
* \return pointer to first element.
*/
#define first_elem(list) ((list)->next)
/**
* Get list last element.
*
* \param list list.
*
* \return pointer to last element.
*/
#define last_elem(list) ((list)->prev)
/**
* Get next element.
*
* \param elem element.
*
* \return pointer to next element.
*/
#define next_elem(elem) ((elem)->next)
/**
* Get previous element.
*
* \param elem element.
*
* \return pointer to previous element.
*/
#define prev_elem(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 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 is_empty_list(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 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 foreach_s(ptr, t, list) \
for(ptr=(list)->next,t=(ptr)->next; list != ptr; ptr=t, t=(t)->next)
#endif /* _U_SIMPLE_LIST_H_ */