LCOV - code coverage report
Current view: top level - include/linux - rbtree.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 1 1 100.0 %
Date: 2017-01-25 Functions: 0 0 -

          Line data    Source code
       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             :   Some example of insert and search follows here. The search is a plain
      27             :   normal search over an ordered tree. The insert instead must be implemented
      28             :   int two steps: as first thing the code must insert the element in
      29             :   order as a red leaf in the tree, then the support library function
      30             :   rb_insert_color() must be called. Such function will do the
      31             :   not trivial work to rebalance the rbtree if necessary.
      32             : 
      33             : -----------------------------------------------------------------------
      34             : static inline struct page * rb_search_page_cache(struct inode * inode,
      35             :                                                  unsigned long offset)
      36             : {
      37             :         struct rb_node * n = inode->i_rb_page_cache.rb_node;
      38             :         struct page * page;
      39             : 
      40             :         while (n)
      41             :         {
      42             :                 page = rb_entry(n, struct page, rb_page_cache);
      43             : 
      44             :                 if (offset < page->offset)
      45             :                         n = n->rb_left;
      46             :                 else if (offset > page->offset)
      47             :                         n = n->rb_right;
      48             :                 else
      49             :                         return page;
      50             :         }
      51             :         return NULL;
      52             : }
      53             : 
      54             : static inline struct page * __rb_insert_page_cache(struct inode * inode,
      55             :                                                    unsigned long offset,
      56             :                                                    struct rb_node * node)
      57             : {
      58             :         struct rb_node ** p = &inode->i_rb_page_cache.rb_node;
      59             :         struct rb_node * parent = NULL;
      60             :         struct page * page;
      61             : 
      62             :         while (*p)
      63             :         {
      64             :                 parent = *p;
      65             :                 page = rb_entry(parent, struct page, rb_page_cache);
      66             : 
      67             :                 if (offset < page->offset)
      68             :                         p = &(*p)->rb_left;
      69             :                 else if (offset > page->offset)
      70             :                         p = &(*p)->rb_right;
      71             :                 else
      72             :                         return page;
      73             :         }
      74             : 
      75             :         rb_link_node(node, parent, p);
      76             : 
      77             :         return NULL;
      78             : }
      79             : 
      80             : static inline struct page * rb_insert_page_cache(struct inode * inode,
      81             :                                                  unsigned long offset,
      82             :                                                  struct rb_node * node)
      83             : {
      84             :         struct page * ret;
      85             :         if ((ret = __rb_insert_page_cache(inode, offset, node)))
      86             :                 goto out;
      87             :         rb_insert_color(node, &inode->i_rb_page_cache);
      88             :  out:
      89             :         return ret;
      90             : }
      91             : -----------------------------------------------------------------------
      92             : */
      93             : 
      94             : #ifndef _LINUX_RBTREE_H
      95             : #define _LINUX_RBTREE_H
      96             : 
      97             : #include <linux/kernel.h>
      98             : #include <linux/stddef.h>
      99             : 
     100             : struct rb_node
     101             : {
     102             :         unsigned long  rb_parent_color;
     103             : #define RB_RED          0
     104             : #define RB_BLACK        1
     105             :         struct rb_node *rb_right;
     106             :         struct rb_node *rb_left;
     107             : } __attribute__((aligned(sizeof(long))));
     108           1 :     /* The alignment might seem pointless, but allegedly CRIS needs it */
     109             : 
     110             : struct rb_root
     111             : {
     112             :         struct rb_node *rb_node;
     113             : };
     114             : 
     115             : 
     116             : #define rb_parent(r)   ((struct rb_node *)((r)->rb_parent_color & ~3))
     117             : #define rb_color(r)   ((r)->rb_parent_color & 1)
     118             : #define rb_is_red(r)   (!rb_color(r))
     119             : #define rb_is_black(r) rb_color(r)
     120             : #define rb_set_red(r)  do { (r)->rb_parent_color &= ~1; } while (0)
     121             : #define rb_set_black(r)  do { (r)->rb_parent_color |= 1; } while (0)
     122             : 
     123             : static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
     124             : {
     125             :         rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p;
     126             : }
     127             : static inline void rb_set_color(struct rb_node *rb, int color)
     128             : {
     129             :         rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
     130             : }
     131             : 
     132             : #define RB_ROOT (struct rb_root) { NULL, }
     133             : #define rb_entry(ptr, type, member) container_of(ptr, type, member)
     134             : 
     135             : #define RB_EMPTY_ROOT(root)     ((root)->rb_node == NULL)
     136             : #define RB_EMPTY_NODE(node)     (rb_parent(node) == node)
     137             : #define RB_CLEAR_NODE(node)     (rb_set_parent(node, node))
     138             : 
     139             : extern void rb_insert_color(struct rb_node *, struct rb_root *);
     140             : extern void rb_erase(struct rb_node *, struct rb_root *);
     141             : 
     142             : /* Find logical next and previous nodes in a tree */
     143             : extern struct rb_node *rb_next(const struct rb_node *);
     144             : extern struct rb_node *rb_prev(const struct rb_node *);
     145             : extern struct rb_node *rb_first(const struct rb_root *);
     146             : extern struct rb_node *rb_last(const struct rb_root *);
     147             : 
     148             : /* Fast replacement of a single node without remove/rebalance/add/rebalance */
     149             : extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, 
     150             :                             struct rb_root *root);
     151             : 
     152             : static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
     153             :                                 struct rb_node ** rb_link)
     154             : {
     155             :         node->rb_parent_color = (unsigned long )parent;
     156             :         node->rb_left = node->rb_right = NULL;
     157             : 
     158             :         *rb_link = node;
     159             : }
     160             : 
     161             : #endif  /* _LINUX_RBTREE_H */

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