1/** 2 * \file simple_list.h 3 * Simple macros for type-safe, intrusive lists. 4 * 5 * Intended to work with a list sentinel which is created as an empty 6 * list. Insert & delete are O(1). 7 * 8 * \author 9 * (C) 1997, Keith Whitwell 10 */ 11 12/* 13 * Mesa 3-D graphics library 14 * Version: 3.5 15 * 16 * Copyright (C) 1999-2001 Brian Paul All Rights Reserved. 17 * 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: 24 * 25 * The above copyright notice and this permission notice shall be included 26 * in all copies or substantial portions of the Software. 27 * 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 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN 32 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 33 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 34 */ 35 36#ifndef _SIMPLE_LIST_H 37#define _SIMPLE_LIST_H 38 39struct simple_node { 40 struct simple_node *next; 41 struct simple_node *prev; 42}; 43 44/** 45 * Remove an element from list. 46 * 47 * \param elem element to remove. 48 */ 49#define remove_from_list(elem) \ 50do { \ 51 (elem)->next->prev = (elem)->prev; \ 52 (elem)->prev->next = (elem)->next; \ 53} while (0) 54 55/** 56 * Insert an element to the list head. 57 * 58 * \param list list. 59 * \param elem element to insert. 60 */ 61#define insert_at_head(list, elem) \ 62do { \ 63 (elem)->prev = list; \ 64 (elem)->next = (list)->next; \ 65 (list)->next->prev = elem; \ 66 (list)->next = elem; \ 67} while(0) 68 69/** 70 * Insert an element to the list tail. 71 * 72 * \param list list. 73 * \param elem element to insert. 74 */ 75#define insert_at_tail(list, elem) \ 76do { \ 77 (elem)->next = list; \ 78 (elem)->prev = (list)->prev; \ 79 (list)->prev->next = elem; \ 80 (list)->prev = elem; \ 81} while(0) 82 83/** 84 * Move an element to the list head. 85 * 86 * \param list list. 87 * \param elem element to move. 88 */ 89#define move_to_head(list, elem) \ 90do { \ 91 remove_from_list(elem); \ 92 insert_at_head(list, elem); \ 93} while (0) 94 95/** 96 * Move an element to the list tail. 97 * 98 * \param list list. 99 * \param elem element to move. 100 */ 101#define move_to_tail(list, elem) \ 102do { \ 103 remove_from_list(elem); \ 104 insert_at_tail(list, elem); \ 105} while (0) 106 107/** 108 * Make a empty list empty. 109 * 110 * \param sentinel list (sentinel element). 111 */ 112#define make_empty_list(sentinel) \ 113do { \ 114 (sentinel)->next = sentinel; \ 115 (sentinel)->prev = sentinel; \ 116} while (0) 117 118/** 119 * Get list first element. 120 * 121 * \param list list. 122 * 123 * \return pointer to first element. 124 */ 125#define first_elem(list) ((list)->next) 126 127/** 128 * Get list last element. 129 * 130 * \param list list. 131 * 132 * \return pointer to last element. 133 */ 134#define last_elem(list) ((list)->prev) 135 136/** 137 * Get next element. 138 * 139 * \param elem element. 140 * 141 * \return pointer to next element. 142 */ 143#define next_elem(elem) ((elem)->next) 144 145/** 146 * Get previous element. 147 * 148 * \param elem element. 149 * 150 * \return pointer to previous element. 151 */ 152#define prev_elem(elem) ((elem)->prev) 153 154/** 155 * Test whether element is at end of the list. 156 * 157 * \param list list. 158 * \param elem element. 159 * 160 * \return non-zero if element is at end of list, or zero otherwise. 161 */ 162#define at_end(list, elem) ((elem) == (list)) 163 164/** 165 * Test if a list is empty. 166 * 167 * \param list list. 168 * 169 * \return non-zero if list empty, or zero otherwise. 170 */ 171#define is_empty_list(list) ((list)->next == (list)) 172 173/** 174 * Walk through the elements of a list. 175 * 176 * \param ptr pointer to the current element. 177 * \param list list. 178 * 179 * \note It should be followed by a { } block or a single statement, as in a \c 180 * for loop. 181 */ 182#define foreach(ptr, list) \ 183 for( ptr=(list)->next ; ptr!=list ; ptr=(ptr)->next ) 184 185/** 186 * Walk through the elements of a list. 187 * 188 * Same as #foreach but lets you unlink the current value during a list 189 * traversal. Useful for freeing a list, element by element. 190 * 191 * \param ptr pointer to the current element. 192 * \param t temporary pointer. 193 * \param list list. 194 * 195 * \note It should be followed by a { } block or a single statement, as in a \c 196 * for loop. 197 */ 198#define foreach_s(ptr, t, list) \ 199 for(ptr=(list)->next,t=(ptr)->next; list != ptr; ptr=t, t=(t)->next) 200 201#endif 202