3 * Simple macros for type-safe, intrusive lists.
5 * Intended to work with a list sentinal which is created as an empty
6 * list. Insert & delete are O(1).
9 * (C) 1997, Keith Whitwell
13 * Mesa 3-D graphics library
16 * Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
18 * Permission is hereby granted, free of charge, to any person obtaining a
19 * copy of this software and associated documentation files (the "Software"),
20 * to deal in the Software without restriction, including without limitation
21 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
22 * and/or sell copies of the Software, and to permit persons to whom the
23 * Software is furnished to do so, subject to the following conditions:
25 * The above copyright notice and this permission notice shall be included
26 * in all copies or substantial portions of the Software.
28 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
29 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
30 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
31 * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
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33 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
37 #ifndef _SIMPLE_LIST_H
38 #define _SIMPLE_LIST_H
45 struct simple_node
*next
;
46 struct simple_node
*prev
;
50 * Remove an element from list.
52 * \param elem element to remove.
54 #define remove_from_list(elem) \
56 (elem)->next->prev = (elem)->prev; \
57 (elem)->prev->next = (elem)->next; \
61 * Insert an element to the list head.
64 * \param elem element to insert.
66 #define insert_at_head(list, elem) \
68 (elem)->prev = list; \
69 (elem)->next = (list)->next; \
70 (list)->next->prev = elem; \
71 (list)->next = elem; \
75 * Insert an element to the list tail.
78 * \param elem element to insert.
80 #define insert_at_tail(list, elem) \
82 (elem)->next = list; \
83 (elem)->prev = (list)->prev; \
84 (list)->prev->next = elem; \
85 (list)->prev = elem; \
89 * Move an element to the list head.
92 * \param elem element to move.
94 #define move_to_head(list, elem) \
96 remove_from_list(elem); \
97 insert_at_head(list, elem); \
101 * Move an element to the list tail.
104 * \param elem element to move.
106 #define move_to_tail(list, elem) \
108 remove_from_list(elem); \
109 insert_at_tail(list, elem); \
113 * Make a empty list empty.
115 * \param sentinal list (sentinal element).
117 #define make_empty_list(sentinal) \
119 (sentinal)->next = sentinal; \
120 (sentinal)->prev = sentinal; \
124 * Get list first element.
128 * \return pointer to first element.
130 #define first_elem(list) ((list)->next)
133 * Get list last element.
137 * \return pointer to last element.
139 #define last_elem(list) ((list)->prev)
144 * \param elem element.
146 * \return pointer to next element.
148 #define next_elem(elem) ((elem)->next)
151 * Get previous element.
153 * \param elem element.
155 * \return pointer to previous element.
157 #define prev_elem(elem) ((elem)->prev)
160 * Test whether element is at end of the list.
163 * \param elem element.
165 * \return non-zero if element is at end of list, or zero otherwise.
167 #define at_end(list, elem) ((elem) == (list))
170 * Test if a list is empty.
174 * \return non-zero if list empty, or zero otherwise.
176 #define is_empty_list(list) ((list)->next == (list))
179 * Walk through the elements of a list.
181 * \param ptr pointer to the current element.
184 * \note It should be followed by a { } block or a single statement, as in a \c
187 #define foreach(ptr, list) \
188 for( ptr=(list)->next ; ptr!=list ; ptr=(ptr)->next )
191 * Walk through the elements of a list.
193 * Same as #foreach but lets you unlink the current value during a list
194 * traversal. Useful for freeing a list, element by element.
196 * \param ptr pointer to the current element.
197 * \param t temporary pointer.
200 * \note It should be followed by a { } block or a single statement, as in a \c
203 #define foreach_s(ptr, t, list) \
204 for(ptr=(list)->next,t=(ptr)->next; list != ptr; ptr=t, t=(t)->next)