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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 genericadt
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. #ifndef KERN_LIST_H_
  36. #define KERN_LIST_H_
  37.  
  38. #include <arch/types.h>
  39. #include <typedefs.h>
  40.  
  41. /** Doubly linked list head and link type. */
  42. typedef struct link {
  43.     struct link *prev;  /**< Pointer to the previous item in the list. */
  44.     struct link *next;  /**< Pointer to the next item in the list. */
  45. } link_t;
  46.  
  47. /** Declare and initialize statically allocated list.
  48.  *
  49.  * @param name Name of the new statically allocated list.
  50.  */
  51. #define LIST_INITIALIZE(name) \
  52.     link_t name = { .prev = &name, .next = &name }
  53.  
  54. /** Initialize doubly-linked circular list link
  55.  *
  56.  * Initialize doubly-linked list link.
  57.  *
  58.  * @param link Pointer to link_t structure to be initialized.
  59.  */
  60. static inline void link_initialize(link_t *link)
  61. {
  62.     link->prev = NULL;
  63.     link->next = NULL;
  64. }
  65.  
  66. /** Initialize doubly-linked circular list
  67.  *
  68.  * Initialize doubly-linked circular list.
  69.  *
  70.  * @param head Pointer to link_t structure representing head of the list.
  71.  */
  72. static inline void list_initialize(link_t *head)
  73. {
  74.     head->prev = head;
  75.     head->next = head;
  76. }
  77.  
  78. /** Add item to the beginning of doubly-linked circular list
  79.  *
  80.  * Add item to the beginning of doubly-linked circular list.
  81.  *
  82.  * @param link Pointer to link_t structure to be added.
  83.  * @param head Pointer to link_t structure representing head of the list.
  84.  */
  85. static inline void list_prepend(link_t *link, link_t *head)
  86. {
  87.     link->next = head->next;
  88.     link->prev = head;
  89.     head->next->prev = link;
  90.     head->next = link;
  91. }
  92.  
  93. /** Add item to the end of doubly-linked circular list
  94.  *
  95.  * Add item to the end of doubly-linked circular list.
  96.  *
  97.  * @param link Pointer to link_t structure to be added.
  98.  * @param head Pointer to link_t structure representing head of the list.
  99.  */
  100. static inline void list_append(link_t *link, link_t *head)
  101. {
  102.     link->prev = head->prev;
  103.     link->next = head;
  104.     head->prev->next = link;
  105.     head->prev = link;
  106. }
  107.  
  108. /** Remove item from doubly-linked circular list
  109.  *
  110.  * Remove item from doubly-linked circular list.
  111.  *
  112.  * @param link  Pointer to link_t structure to be removed from the list it is
  113.  *      contained in.
  114.  */
  115. static inline void list_remove(link_t *link)
  116. {
  117.     link->next->prev = link->prev;
  118.     link->prev->next = link->next;
  119.     link_initialize(link);
  120. }
  121.  
  122. /** Query emptiness of doubly-linked circular list
  123.  *
  124.  * Query emptiness of doubly-linked circular list.
  125.  *
  126.  * @param head Pointer to link_t structure representing head of the list.
  127.  */
  128. static inline bool list_empty(link_t *head)
  129. {
  130.     return head->next == head ? true : false;
  131. }
  132.  
  133.  
  134. /** Split or concatenate headless doubly-linked circular list
  135.  *
  136.  * Split or concatenate headless doubly-linked circular list.
  137.  *
  138.  * Note that the algorithm works both directions:
  139.  * concatenates splitted lists and splits concatenated lists.
  140.  *
  141.  * @param part1 Pointer to link_t structure leading the first (half of the
  142.  *      headless) list.
  143.  * @param part2 Pointer to link_t structure leading the second (half of the
  144.  *      headless) list.
  145.  */
  146. static inline void headless_list_split_or_concat(link_t *part1, link_t *part2)
  147. {
  148.     link_t *hlp;
  149.  
  150.     part1->prev->next = part2;
  151.     part2->prev->next = part1; 
  152.     hlp = part1->prev;
  153.     part1->prev = part2->prev;
  154.     part2->prev = hlp;
  155. }
  156.  
  157.  
  158. /** Split headless doubly-linked circular list
  159.  *
  160.  * Split headless doubly-linked circular list.
  161.  *
  162.  * @param part1 Pointer to link_t structure leading the first half of the
  163.  *      headless list.
  164.  * @param part2 Pointer to link_t structure leading the second half of the
  165.  *      headless list.
  166.  */
  167. static inline void headless_list_split(link_t *part1, link_t *part2)
  168. {
  169.     headless_list_split_or_concat(part1, part2);
  170. }
  171.  
  172. /** Concatenate two headless doubly-linked circular lists
  173.  *
  174.  * Concatenate two headless doubly-linked circular lists.
  175.  *
  176.  * @param part1 Pointer to link_t structure leading the first headless list.
  177.  * @param part2 Pointer to link_t structure leading the second headless list.
  178.  */
  179. static inline void headless_list_concat(link_t *part1, link_t *part2)
  180. {
  181.     headless_list_split_or_concat(part1, part2);
  182. }
  183.  
  184. #define list_get_instance(link, type, member) \
  185.     ((type *)(((uint8_t *)(link)) - ((uint8_t *)&(((type *)NULL)->member))))
  186.  
  187. extern bool list_member(const link_t *link, const link_t *head);
  188. extern void list_concat(link_t *head1, link_t *head2);
  189.  
  190. #endif
  191.  
  192. /** @}
  193.  */
  194.