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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. #ifndef __LIST_H__
  30. #define __LIST_H__
  31.  
  32. #include <arch/types.h>
  33. #include <typedefs.h>
  34.  
  35. /** Doubly linked list head and link type. */
  36. struct link {
  37.     link_t *prev;   /**< Pointer to the previous item in the list. */
  38.     link_t *next;   /**< Pointer to the next item in the list. */
  39. };
  40.  
  41. /** Declare and initialize statically allocated list.
  42.  *
  43.  * @param name Name of the new statically allocated list.
  44.  */
  45. #define LIST_INITIALIZE(name)       link_t name = { .prev = &name, .next = &name }
  46.  
  47. /** Initialize doubly-linked circular list link
  48.  *
  49.  * Initialize doubly-linked list link.
  50.  *
  51.  * @param link Pointer to link_t structure to be initialized.
  52.  */
  53. static inline void link_initialize(link_t *link)
  54. {
  55.     link->prev = NULL;
  56.     link->next = NULL;
  57. }
  58.  
  59. /** Initialize doubly-linked circular list
  60.  *
  61.  * Initialize doubly-linked circular list.
  62.  *
  63.  * @param head Pointer to link_t structure representing head of the list.
  64.  */
  65. static inline void list_initialize(link_t *head)
  66. {
  67.     head->prev = head;
  68.     head->next = head;
  69. }
  70.  
  71. /** Add item to the beginning of doubly-linked circular list
  72.  *
  73.  * Add item to the beginning of doubly-linked circular list.
  74.  *
  75.  * @param link Pointer to link_t structure to be added.
  76.  * @param head Pointer to link_t structure representing head of the list.
  77.  */
  78. static inline void list_prepend(link_t *link, link_t *head)
  79. {
  80.     link->next = head->next;
  81.     link->prev = head;
  82.     head->next->prev = link;
  83.     head->next = link;
  84. }
  85.  
  86. /** Add item to the end of doubly-linked circular list
  87.  *
  88.  * Add item to the end of doubly-linked circular list.
  89.  *
  90.  * @param link Pointer to link_t structure to be added.
  91.  * @param head Pointer to link_t structure representing head of the list.
  92.  */
  93. static inline void list_append(link_t *link, link_t *head)
  94. {
  95.     link->prev = head->prev;
  96.     link->next = head;
  97.     head->prev->next = link;
  98.     head->prev = link;
  99. }
  100.  
  101. /** Remove item from doubly-linked circular list
  102.  *
  103.  * Remove item from doubly-linked circular list.
  104.  *
  105.  * @param link Pointer to link_t structure to be removed from the list it is contained in.
  106.  */
  107. static inline void list_remove(link_t *link)
  108. {
  109.     link->next->prev = link->prev;
  110.     link->prev->next = link->next;
  111.     link_initialize(link);
  112. }
  113.  
  114. /** Query emptiness of doubly-linked circular list
  115.  *
  116.  * Query emptiness of doubly-linked circular list.
  117.  *
  118.  * @param head Pointer to link_t structure representing head of the list.
  119.  */
  120. static inline bool list_empty(link_t *head)
  121. {
  122.     return head->next == head ? true : false;
  123. }
  124.  
  125.  
  126. /** Split or concatenate headless doubly-linked circular list
  127.  *
  128.  * Split or concatenate headless doubly-linked circular list.
  129.  *
  130.  * Note that the algorithm works both directions:
  131.  * concatenates splitted lists and splits concatenated lists.
  132.  *
  133.  * @param part1 Pointer to link_t structure leading the first (half of the headless) list.
  134.  * @param part2 Pointer to link_t structure leading the second (half of the headless) list.
  135.  */
  136. static inline void headless_list_split_or_concat(link_t *part1, link_t *part2)
  137. {
  138.     link_t *hlp;
  139.  
  140.     part1->prev->next = part2;
  141.     part2->prev->next = part1; 
  142.     hlp = part1->prev;
  143.     part1->prev = part2->prev;
  144.     part2->prev = hlp;
  145. }
  146.  
  147.  
  148. /** Split headless doubly-linked circular list
  149.  *
  150.  * Split headless doubly-linked circular list.
  151.  *
  152.  * @param part1 Pointer to link_t structure leading the first half of the headless list.
  153.  * @param part2 Pointer to link_t structure leading the second half of the headless list.
  154.  */
  155. static inline void headless_list_split(link_t *part1, link_t *part2)
  156. {
  157.     headless_list_split_or_concat(part1, part2);
  158. }
  159.  
  160. /** Concatenate two headless doubly-linked circular lists
  161.  *
  162.  * Concatenate two headless doubly-linked circular lists.
  163.  *
  164.  * @param part1 Pointer to link_t structure leading the first headless list.
  165.  * @param part2 Pointer to link_t structure leading the second headless list.
  166.  */
  167. static inline void headless_list_concat(link_t *part1, link_t *part2)
  168. {
  169.     headless_list_split_or_concat(part1, part2);
  170. }
  171.  
  172. #define list_get_instance(link,type,member) (type *)(((__u8*)(link))-((__u8*)&(((type *)NULL)->member)))
  173.  
  174. extern bool list_member(const link_t *link, const link_t *head);
  175. extern void list_concat(link_t *head1, link_t *head2);
  176.  
  177. #endif
  178.