1 /** 2 * \file simple_list.h 3 * Simple macros for type-safe, intrusive lists. 4 * 5 * Intended to work with a list sentinal 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 37 #ifndef _SIMPLE_LIST_H 38 #define _SIMPLE_LIST_H 39 40 #ifdef __cplusplus 41 extern "C" { 42 #endif 43 44 struct simple_node { 45 struct simple_node *next; 46 struct simple_node *prev; 47 }; 48 49 /** 50 * Remove an element from list. 51 * 52 * \param elem element to remove. 53 */ 54 #define remove_from_list(elem) \ 55 do { \ 56 (elem)->next->prev = (elem)->prev; \ 57 (elem)->prev->next = (elem)->next; \ 58 } while (0) 59 60 /** 61 * Insert an element to the list head. 62 * 63 * \param list list. 64 * \param elem element to insert. 65 */ 66 #define insert_at_head(list, elem) \ 67 do { \ 68 (elem)->prev = list; \ 69 (elem)->next = (list)->next; \ 70 (list)->next->prev = elem; \ 71 (list)->next = elem; \ 72 } while(0) 73 74 /** 75 * Insert an element to the list tail. 76 * 77 * \param list list. 78 * \param elem element to insert. 79 */ 80 #define insert_at_tail(list, elem) \ 81 do { \ 82 (elem)->next = list; \ 83 (elem)->prev = (list)->prev; \ 84 (list)->prev->next = elem; \ 85 (list)->prev = elem; \ 86 } while(0) 87 88 /** 89 * Move an element to the list head. 90 * 91 * \param list list. 92 * \param elem element to move. 93 */ 94 #define move_to_head(list, elem) \ 95 do { \ 96 remove_from_list(elem); \ 97 insert_at_head(list, elem); \ 98 } while (0) 99 100 /** 101 * Move an element to the list tail. 102 * 103 * \param list list. 104 * \param elem element to move. 105 */ 106 #define move_to_tail(list, elem) \ 107 do { \ 108 remove_from_list(elem); \ 109 insert_at_tail(list, elem); \ 110 } while (0) 111 112 /** 113 * Make a empty list empty. 114 * 115 * \param sentinal list (sentinal element). 116 */ 117 #define make_empty_list(sentinal) \ 118 do { \ 119 (sentinal)->next = sentinal; \ 120 (sentinal)->prev = sentinal; \ 121 } while (0) 122 123 /** 124 * Get list first element. 125 * 126 * \param list list. 127 * 128 * \return pointer to first element. 129 */ 130 #define first_elem(list) ((list)->next) 131 132 /** 133 * Get list last element. 134 * 135 * \param list list. 136 * 137 * \return pointer to last element. 138 */ 139 #define last_elem(list) ((list)->prev) 140 141 /** 142 * Get next element. 143 * 144 * \param elem element. 145 * 146 * \return pointer to next element. 147 */ 148 #define next_elem(elem) ((elem)->next) 149 150 /** 151 * Get previous element. 152 * 153 * \param elem element. 154 * 155 * \return pointer to previous element. 156 */ 157 #define prev_elem(elem) ((elem)->prev) 158 159 /** 160 * Test whether element is at end of the list. 161 * 162 * \param list list. 163 * \param elem element. 164 * 165 * \return non-zero if element is at end of list, or zero otherwise. 166 */ 167 #define at_end(list, elem) ((elem) == (list)) 168 169 /** 170 * Test if a list is empty. 171 * 172 * \param list list. 173 * 174 * \return non-zero if list empty, or zero otherwise. 175 */ 176 #define is_empty_list(list) ((list)->next == (list)) 177 178 /** 179 * Walk through the elements of a list. 180 * 181 * \param ptr pointer to the current element. 182 * \param list list. 183 * 184 * \note It should be followed by a { } block or a single statement, as in a \c 185 * for loop. 186 */ 187 #define foreach(ptr, list) \ 188 for( ptr=(list)->next ; ptr!=list ; ptr=(ptr)->next ) 189 190 /** 191 * Walk through the elements of a list. 192 * 193 * Same as #foreach but lets you unlink the current value during a list 194 * traversal. Useful for freeing a list, element by element. 195 * 196 * \param ptr pointer to the current element. 197 * \param t temporary pointer. 198 * \param list list. 199 * 200 * \note It should be followed by a { } block or a single statement, as in a \c 201 * for loop. 202 */ 203 #define foreach_s(ptr, t, list) \ 204 for(ptr=(list)->next,t=(ptr)->next; list != ptr; ptr=t, t=(t)->next) 205 206 #ifdef __cplusplus 207 } 208 #endif 209 210 #endif 211