nptl/sysdeps/pthread/list.h

   1 /* Copyright (C) 2002, 2009, 2011 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _LIST_H
  21
  22 #ifndef __need_list_t
  23 # define _LIST_H        1
  24 #endif
  25
  26 /* The definitions of this file are adopted from those which can be
  27    found in the Linux kernel headers to enable people familiar with
  28    the latter find their way in these sources as well.  */
  29
  30
  31 #if defined __need_list_t || defined _LIST_H
  32 # ifndef __list_t_defined
  33 #  define __list_t_defined
  34 /* Basic type for the double-link list.  */
  35 typedef struct list_head
  36 {
  37   struct list_head *next;
  38   struct list_head *prev;
  39 } list_t;
  40 # endif
  41 # undef __need_list_t
  42 #endif
  43
  44 #ifdef _LIST_H
  45
  46 # include <atomic.h>
  47
  48 /* Define a variable with the head and tail of the list.  */
  49 # define LIST_HEAD(name) \
  50   list_t name = { &(name), &(name) }
  51
  52 /* Initialize a new list head.  */
  53 # define INIT_LIST_HEAD(ptr) \
  54   (ptr)->next = (ptr)->prev = (ptr)
  55
  56
  57 /* Add new element at the head of the list.  */
  58 static inline void
  59 list_add (list_t *newp, list_t *head)
  60 {
  61   newp->next = head->next;
  62   newp->prev = head;
  63   head->next->prev = newp;
  64   atomic_write_barrier ();
  65   head->next = newp;
  66 }
  67
  68
  69 /* Remove element from list.  */
  70 static inline void
  71 list_del (list_t *elem)
  72 {
  73   elem->next->prev = elem->prev;
  74   elem->prev->next = elem->next;
  75 }
  76
  77
  78 /* Join two lists.  */
  79 static inline void
  80 list_splice (list_t *add, list_t *head)
  81 {
  82   /* Do nothing if the list which gets added is empty.  */
  83   if (add != add->next)
  84     {
  85       add->next->prev = head;
  86       add->prev->next = head->next;
  87       head->next->prev = add->prev;
  88       head->next = add->next;
  89     }
  90 }
  91
  92
  93 /* Get typed element from list at a given position.  */
  94 # define list_entry(ptr, type, member) \
  95   ((type *) ((char *) (ptr) - (unsigned long) (&((type *) 0)->member)))
  96
  97
  98
  99 /* Iterate forward over the elements of the list.  */
 100 # define list_for_each(pos, head) \
 101   for (pos = (head)->next; pos != (head); pos = pos->next)
 102
 103
 104 /* Iterate forward over the elements of the list.  */
 105 # define list_for_each_prev(pos, head) \
 106   for (pos = (head)->prev; pos != (head); pos = pos->prev)
 107
 108
 109 /* Iterate backwards over the elements list.  The list elements can be
 110    removed from the list while doing this.  */
 111 # define list_for_each_prev_safe(pos, p, head) \
 112   for (pos = (head)->prev, p = pos->prev; \
 113        pos != (head); \
 114        pos = p, p = pos->prev)
 115
 116 #endif /* _LIST_H */
 117
 118 #endif  /* list.h */