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  1. /*
  2.  * Copyright (c) 2001-2004 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup libc
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. #ifndef LIBC_LIST_H_
  36. #define LIBC_LIST_H_
  37.  
  38. #include <unistd.h>
  39.  
  40. #ifndef true
  41. # define true 1
  42. #endif
  43. #ifndef false
  44. # define false 0
  45. #endif
  46.  
  47. typedef struct link link_t;
  48.  
  49. /** Doubly linked list head and link type. */
  50. struct link {
  51.     link_t *prev;   /**< Pointer to the previous item in the list. */
  52.     link_t *next;   /**< Pointer to the next item in the list. */
  53. };
  54.  
  55. /** Declare and initialize statically allocated list.
  56.  *
  57.  * @param name Name of the new statically allocated list.
  58.  */
  59. #define LIST_INITIALIZE(name)       link_t name = { .prev = &name, .next = &name }
  60.  
  61. /** Initialize doubly-linked circular list link
  62.  *
  63.  * Initialize doubly-linked list link.
  64.  *
  65.  * @param link Pointer to link_t structure to be initialized.
  66.  */
  67. static inline void link_initialize(link_t *link)
  68. {
  69.     link->prev = NULL;
  70.     link->next = NULL;
  71. }
  72.  
  73. /** Initialize doubly-linked circular list
  74.  *
  75.  * Initialize doubly-linked circular list.
  76.  *
  77.  * @param head Pointer to link_t structure representing head of the list.
  78.  */
  79. static inline void list_initialize(link_t *head)
  80. {
  81.     head->prev = head;
  82.     head->next = head;
  83. }
  84.  
  85. /** Add item to the beginning of doubly-linked circular list
  86.  *
  87.  * Add item to the beginning of doubly-linked circular list.
  88.  *
  89.  * @param link Pointer to link_t structure to be added.
  90.  * @param head Pointer to link_t structure representing head of the list.
  91.  */
  92. static inline void list_prepend(link_t *link, link_t *head)
  93. {
  94.     link->next = head->next;
  95.     link->prev = head;
  96.     head->next->prev = link;
  97.     head->next = link;
  98. }
  99.  
  100. /** Add item to the end of doubly-linked circular list
  101.  *
  102.  * Add item to the end of doubly-linked circular list.
  103.  *
  104.  * @param link Pointer to link_t structure to be added.
  105.  * @param head Pointer to link_t structure representing head of the list.
  106.  */
  107. static inline void list_append(link_t *link, link_t *head)
  108. {
  109.     link->prev = head->prev;
  110.     link->next = head;
  111.     head->prev->next = link;
  112.     head->prev = link;
  113. }
  114.  
  115. /** Insert item before another item in doubly-linked circular list. */
  116. static inline void list_insert_before(link_t *l, link_t *r)
  117. {
  118.     list_append(l, r);
  119. }
  120.  
  121. /** Insert item after another item in doubly-linked circular list. */
  122. static inline void list_insert_after(link_t *r, link_t *l)
  123. {
  124.     list_prepend(l, r);
  125. }
  126.  
  127. /** Remove item from doubly-linked circular list
  128.  *
  129.  * Remove item from doubly-linked circular list.
  130.  *
  131.  * @param link Pointer to link_t structure to be removed from the list it is contained in.
  132.  */
  133. static inline void list_remove(link_t *link)
  134. {
  135.     link->next->prev = link->prev;
  136.     link->prev->next = link->next;
  137.     link_initialize(link);
  138. }
  139.  
  140. /** Query emptiness of doubly-linked circular list
  141.  *
  142.  * Query emptiness of doubly-linked circular list.
  143.  *
  144.  * @param head Pointer to link_t structure representing head of the list.
  145.  */
  146. static inline int list_empty(link_t *head)
  147. {
  148.     return head->next == head ? true : false;
  149. }
  150.  
  151.  
  152. /** Split or concatenate headless doubly-linked circular list
  153.  *
  154.  * Split or concatenate headless doubly-linked circular list.
  155.  *
  156.  * Note that the algorithm works both directions:
  157.  * concatenates splitted lists and splits concatenated lists.
  158.  *
  159.  * @param part1 Pointer to link_t structure leading the first (half of the headless) list.
  160.  * @param part2 Pointer to link_t structure leading the second (half of the headless) list.
  161.  */
  162. static inline void headless_list_split_or_concat(link_t *part1, link_t *part2)
  163. {
  164.     link_t *hlp;
  165.  
  166.     part1->prev->next = part2;
  167.     part2->prev->next = part1; 
  168.     hlp = part1->prev;
  169.     part1->prev = part2->prev;
  170.     part2->prev = hlp;
  171. }
  172.  
  173.  
  174. /** Split headless doubly-linked circular list
  175.  *
  176.  * Split headless doubly-linked circular list.
  177.  *
  178.  * @param part1 Pointer to link_t structure leading the first half of the headless list.
  179.  * @param part2 Pointer to link_t structure leading the second half of the headless list.
  180.  */
  181. static inline void headless_list_split(link_t *part1, link_t *part2)
  182. {
  183.     headless_list_split_or_concat(part1, part2);
  184. }
  185.  
  186. /** Concatenate two headless doubly-linked circular lists
  187.  *
  188.  * Concatenate two headless doubly-linked circular lists.
  189.  *
  190.  * @param part1 Pointer to link_t structure leading the first headless list.
  191.  * @param part2 Pointer to link_t structure leading the second headless list.
  192.  */
  193. static inline void headless_list_concat(link_t *part1, link_t *part2)
  194. {
  195.     headless_list_split_or_concat(part1, part2);
  196. }
  197.  
  198. #define list_get_instance(link,type,member) (type *)(((char *)(link))-((char *)&(((type *)NULL)->member)))
  199.  
  200. extern int list_member(const link_t *link, const link_t *head);
  201. extern void list_concat(link_t *head1, link_t *head2);
  202.  
  203. #endif
  204.  
  205. /** @}
  206.  */
  207.