include/linux/rbtree.h

   1 /*
   2   Red Black Trees
   3   (C) 1999  Andrea Arcangeli <andrea@suse.de>
   4
   5   This program is free software; you can redistribute it and/or modify
   6   it under the terms of the GNU General Public License as published by
   7   the Free Software Foundation; either version 2 of the License, or
   8   (at your option) any later version.
   9
  10   This program 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
  13   GNU General Public License for more details.
  14
  15   You should have received a copy of the GNU General Public License
  16   along with this program; if not, write to the Free Software
  17   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18
  19   linux/include/linux/rbtree.h
  20
  21   To use rbtrees you'll have to implement your own insert and search cores.
  22   This will avoid us to use callbacks and to drop drammatically performances.
  23   I know it's not the cleaner way,  but in C (not in C++) to get
  24   performances and genericity...
  25
  26   See Documentation/rbtree.txt for documentation and samples.
  27 */
  28
  29 #ifndef _LINUX_RBTREE_H
  30 #define _LINUX_RBTREE_H
  31
  32 #include <linux/kernel.h>
  33 #include <linux/stddef.h>
  34
  35 struct rb_node {
  36         unsigned long  __rb_parent_color;
  37         struct rb_node *rb_right;
  38         struct rb_node *rb_left;
  39 } __attribute__((aligned(sizeof(long))));
  40     /* The alignment might seem pointless, but allegedly CRIS needs it */
  41
  42 struct rb_root {
  43         struct rb_node *rb_node;
  44 };
  45
  46
  47 #define rb_parent(r)   ((struct rb_node *)((r)->__rb_parent_color & ~3))
  48
  49 #define RB_ROOT (struct rb_root) { NULL, }
  50 #define rb_entry(ptr, type, member) container_of(ptr, type, member)
  51
  52 #define RB_EMPTY_ROOT(root)  ((root)->rb_node == NULL)
  53
  54 /* 'empty' nodes are nodes that are known not to be inserted in an rbree */
  55 #define RB_EMPTY_NODE(node)  \
  56         ((node)->__rb_parent_color == (unsigned long)(node))
  57 #define RB_CLEAR_NODE(node)  \
  58         ((node)->__rb_parent_color = (unsigned long)(node))
  59
  60
  61 extern void rb_insert_color(struct rb_node *, struct rb_root *);
  62 extern void rb_erase(struct rb_node *, struct rb_root *);
  63
  64
  65 /* Find logical next and previous nodes in a tree */
  66 extern struct rb_node *rb_next(const struct rb_node *);
  67 extern struct rb_node *rb_prev(const struct rb_node *);
  68 extern struct rb_node *rb_first(const struct rb_root *);
  69 extern struct rb_node *rb_last(const struct rb_root *);
  70
  71 /* Fast replacement of a single node without remove/rebalance/add/rebalance */
  72 extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
  73                             struct rb_root *root);
  74
  75 static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
  76                                 struct rb_node ** rb_link)
  77 {
  78         node->__rb_parent_color = (unsigned long)parent;
  79         node->rb_left = node->rb_right = NULL;
  80
  81         *rb_link = node;
  82 }
  83
  84 #endif  /* _LINUX_RBTREE_H */