src/rbtree.h

   1 /*
   2  * nao-ulib
   3  * Copyright 2011 Daniel Borkmann <dborkma@tik.ee.ethz.ch>
   4  * Subject to the GPL.
   5  * Nao-Team HTWK,
   6  * Faculty of Computer Science, Mathematics and Natural Sciences,
   7  * Leipzig University of Applied Sciences (HTWK Leipzig)
   8  */
   9
  10 /*
  11  * Red Black Trees
  12  * (C) 1999  Andrea Arcangeli <andrea@suse.de>
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  27  *
  28  * linux/include/linux/rbtree.h
  29  *
  30  * To use rbtrees you'll have to implement your own insert and search cores.
  31  * This will avoid us to use callbacks and to drop drammatically performances.
  32  * I know it's not the cleaner way,  but in C (not in C++) to get
  33  * performances and genericity...
  34  *
  35  * Some example of insert and search follows here. The search is a plain
  36  * normal search over an ordered tree. The insert instead must be implemented
  37  * int two steps: as first thing the code must insert the element in
  38  * order as a red leaf in the tree, then the support library function
  39  * rb_insert_color() must be called. Such function will do the
  40  * not trivial work to rebalance the rbtree if necessary.
  41  *
  42    -----------------------------------------------------------------------
  43    static inline struct page * rb_search_page_cache(struct inode * inode,
  44                                                  unsigned long offset)
  45    {
  46         struct rb_node * n = inode->i_rb_page_cache.rb_node;
  47         struct page * page;
  48
  49         while (n)
  50         {
  51                 page = rb_entry(n, struct page, rb_page_cache);
  52
  53                 if (offset < page->offset)
  54                         n = n->rb_left;
  55                 else if (offset > page->offset)
  56                         n = n->rb_right;
  57                 else
  58                         return page;
  59         }
  60         return NULL;
  61    }
  62
  63    static inline struct page * __rb_insert_page_cache(struct inode * inode,
  64                                                    unsigned long offset,
  65                                                    struct rb_node * node)
  66    {
  67         struct rb_node ** p = &inode->i_rb_page_cache.rb_node;
  68         struct rb_node * parent = NULL;
  69         struct page * page;
  70
  71         while (*p)
  72         {
  73                 parent = *p;
  74                 page = rb_entry(parent, struct page, rb_page_cache);
  75
  76                 if (offset < page->offset)
  77                         p = &(*p)->rb_left;
  78                 else if (offset > page->offset)
  79                         p = &(*p)->rb_right;
  80                 else
  81                         return page;
  82         }
  83
  84         rb_link_node(node, parent, p);
  85
  86         return NULL;
  87    }
  88
  89    static inline struct page * rb_insert_page_cache(struct inode * inode,
  90                                                  unsigned long offset,
  91                                                  struct rb_node * node)
  92    {
  93         struct page * ret;
  94         if ((ret = __rb_insert_page_cache(inode, offset, node)))
  95                 goto out;
  96         rb_insert_color(node, &inode->i_rb_page_cache);
  97     out:
  98         return ret;
  99    }
 100    -----------------------------------------------------------------------
 101  */
 102
 103 #ifndef RBTREE_H
 104 #define RBTREE_H
 105
 106 struct rb_node
 107 {
 108         unsigned long  rb_parent_color;
 109 #define RB_RED          0
 110 #define RB_BLACK        1
 111         struct rb_node *rb_right;
 112         struct rb_node *rb_left;
 113 } __attribute__((aligned(sizeof(long))));
 114 /* The alignment might seem pointless, but allegedly CRIS needs it */
 115
 116 struct rb_root
 117 {
 118         struct rb_node *rb_node;
 119 };
 120
 121 #define rb_parent(r)   ((struct rb_node *)((r)->rb_parent_color & ~3))
 122 #define rb_color(r)   ((r)->rb_parent_color & 1)
 123 #define rb_is_red(r)   (!rb_color(r))
 124 #define rb_is_black(r) rb_color(r)
 125 #define rb_set_red(r)  do { (r)->rb_parent_color &= ~1; } while (0)
 126 #define rb_set_black(r)  do { (r)->rb_parent_color |= 1; } while (0)
 127
 128 static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
 129 {
 130         rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p;
 131 }
 132 static inline void rb_set_color(struct rb_node *rb, int color)
 133 {
 134         rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
 135 }
 136
 137 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 138
 139 #define container_of(ptr, type, member) ({                      \
 140         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 141         (type *)( (char *)__mptr - offsetof(type,member) );})
 142
 143 #define RB_ROOT (struct rb_root) { NULL, }
 144 #define rb_entry(ptr, type, member) container_of(ptr, type, member)
 145
 146 #define RB_EMPTY_ROOT(root)     ((root)->rb_node == NULL)
 147 #define RB_EMPTY_NODE(node)     (rb_parent(node) == node)
 148 #define RB_CLEAR_NODE(node)     (rb_set_parent(node, node))
 149
 150 extern void rb_insert_color(struct rb_node *, struct rb_root *);
 151 extern void rb_erase(struct rb_node *, struct rb_root *);
 152
 153 /* Find logical next and previous nodes in a tree */
 154 extern struct rb_node *rb_next(struct rb_node *);
 155 extern struct rb_node *rb_prev(struct rb_node *);
 156 extern struct rb_node *rb_first(struct rb_root *);
 157 extern struct rb_node *rb_last(struct rb_root *);
 158
 159 /* Fast replacement of a single node without remove/rebalance/add/rebalance */
 160 extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
 161                             struct rb_root *root);
 162
 163 static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
 164                                 struct rb_node ** rb_link)
 165 {
 166         node->rb_parent_color = (unsigned long )parent;
 167         node->rb_left = node->rb_right = NULL;
 168
 169         *rb_link = node;
 170 }
 171
 172 #endif /* RBTREE_H */