uspace/libc/generic/libadt/list.c

   1 /*
   2  * Copyright (c) 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 #include <libadt/list.h>
  36
  37
  38 /** Check for membership
  39  *
  40  * Check whether link is contained in the list head.
  41  * The membership is defined as pointer equivalence.
  42  *
  43  * @param link Item to look for.
  44  * @param head List to look in.
  45  *
  46  * @return true if link is contained in head, false otherwise.
  47  *
  48  */
  49 int list_member(const link_t *link, const link_t *head)
  50 {
  51         int found = false;
  52         link_t *hlp = head->next;
  53
  54         while (hlp != head) {
  55                 if (hlp == link) {
  56                         found = true;
  57                         break;
  58                 }
  59                 hlp = hlp->next;
  60         }
  61
  62         return found;
  63 }
  64
  65
  66 /** Concatenate two lists
  67  *
  68  * Concatenate lists head1 and head2, producing a single
  69  * list head1 containing items from both (in head1, head2
  70  * order) and empty list head2.
  71  *
  72  * @param head1 First list and concatenated output
  73  * @param head2 Second list and empty output.
  74  *
  75  */
  76 void list_concat(link_t *head1, link_t *head2)
  77 {
  78         if (list_empty(head2))
  79                 return;
  80
  81         head2->next->prev = head1->prev;
  82         head2->prev->next = head1;
  83         head1->prev->next = head2->next;
  84         head1->prev = head2->prev;
  85         list_initialize(head2);
  86 }
  87
  88 /** @}
  89  */