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