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 * 15 * Copyright (C) 1999-2001 Brian Paul All Rights Reserved. 16 * 17 * Permission is hereby granted, free of charge, to any person obtaining a 18 * copy of this software and associated documentation files (the "Software"), 19 * to deal in the Software without restriction, including without limitation 20 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 21 * and/or sell copies of the Software, and to permit persons to whom the 22 * Software is furnished to do so, subject to the following conditions: 23 * 24 * The above copyright notice and this permission notice shall be included 25 * in all copies or substantial portions of the Software. 26 * 27 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 28 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 29 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 30 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 31 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 32 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 33 * 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 make_empty_list(elem); \ 59 } while (0) 60 61 /** 62 * Insert an element to the list head. 63 * 64 * \param list list. 65 * \param elem element to insert. 66 */ 67 #define insert_at_head(list, elem) \ 68 do { \ 69 (elem)->prev = list; \ 70 (elem)->next = (list)->next; \ 71 (list)->next->prev = elem; \ 72 (list)->next = elem; \ 73 } while(0) 74 75 /** 76 * Insert an element to the list tail. 77 * 78 * \param list list. 79 * \param elem element to insert. 80 */ 81 #define insert_at_tail(list, elem) \ 82 do { \ 83 (elem)->next = list; \ 84 (elem)->prev = (list)->prev; \ 85 (list)->prev->next = elem; \ 86 (list)->prev = elem; \ 87 } while(0) 88 89 /** 90 * Move an element to the list head. 91 * 92 * \param list list. 93 * \param elem element to move. 94 */ 95 #define move_to_head(list, elem) \ 96 do { \ 97 remove_from_list(elem); \ 98 insert_at_head(list, elem); \ 99 } while (0) 100 101 /** 102 * Move an element to the list tail. 103 * 104 * \param list list. 105 * \param elem element to move. 106 */ 107 #define move_to_tail(list, elem) \ 108 do { \ 109 remove_from_list(elem); \ 110 insert_at_tail(list, elem); \ 111 } while (0) 112 113 /** 114 * Make a empty list empty. 115 * 116 * \param sentinal list (sentinal element). 117 */ 118 #define make_empty_list(sentinal) \ 119 do { \ 120 (sentinal)->next = sentinal; \ 121 (sentinal)->prev = sentinal; \ 122 } while (0) 123 124 /** 125 * Get list first element. 126 * 127 * \param list list. 128 * 129 * \return pointer to first element. 130 */ 131 #define first_elem(list) ((list)->next) 132 133 /** 134 * Get list last element. 135 * 136 * \param list list. 137 * 138 * \return pointer to last element. 139 */ 140 #define last_elem(list) ((list)->prev) 141 142 /** 143 * Get next element. 144 * 145 * \param elem element. 146 * 147 * \return pointer to next element. 148 */ 149 #define next_elem(elem) ((elem)->next) 150 151 /** 152 * Get previous element. 153 * 154 * \param elem element. 155 * 156 * \return pointer to previous element. 157 */ 158 #define prev_elem(elem) ((elem)->prev) 159 160 /** 161 * Test whether element is at end of the list. 162 * 163 * \param list list. 164 * \param elem element. 165 * 166 * \return non-zero if element is at end of list, or zero otherwise. 167 */ 168 #define at_end(list, elem) ((elem) == (list)) 169 170 /** 171 * Test if a list is empty. 172 * 173 * \param list list. 174 * 175 * \return non-zero if list empty, or zero otherwise. 176 */ 177 #define is_empty_list(list) ((list)->next == (list)) 178 179 /** 180 * Walk through the elements of a list. 181 * 182 * \param ptr pointer to the current element. 183 * \param list list. 184 * 185 * \note It should be followed by a { } block or a single statement, as in a \c 186 * for loop. 187 */ 188 #define foreach(ptr, list) \ 189 for( ptr=(list)->next ; ptr!=list ; ptr=(ptr)->next ) 190 191 /** 192 * Walk through the elements of a list. 193 * 194 * Same as #foreach but lets you unlink the current value during a list 195 * traversal. Useful for freeing a list, element by element. 196 * 197 * \param ptr pointer to the current element. 198 * \param t temporary pointer. 199 * \param list list. 200 * 201 * \note It should be followed by a { } block or a single statement, as in a \c 202 * for loop. 203 */ 204 #define foreach_s(ptr, t, list) \ 205 for(ptr=(list)->next,t=(ptr)->next; list != ptr; ptr=t, t=(t)->next) 206 207 #ifdef __cplusplus 208 } 209 #endif 210 211 #endif 212
