LCOV - code coverage report
Current view: top level - root/cov/dir/include - rbtree.h (source / functions) Hit Total Coverage
Test: a simple test Lines: 3 3 100.0 %
Date: 2024-06-05 20:10:43 Functions: 0 0 -
Legend: Lines: hit not hit

          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             :     /* 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             : 
     134             : /* Newer gcc versions take care of exporting this */
     135             : #ifndef offsetof
     136             : #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
     137             : #endif
     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_entry(ptr, type, member) container_of(ptr, type, member)
     144             : 
     145             : #define RB_EMPTY_ROOT(root)     ((root)->rb_node == NULL)
     146             : #define RB_EMPTY_NODE(node)     (rb_parent(node) == node)
     147             : #define RB_CLEAR_NODE(node)     (rb_set_parent(node, node))
     148             : 
     149             : extern void rb_insert_color(struct rb_node *, struct rb_root *);
     150             : extern void rb_erase(struct rb_node *, struct rb_root *);
     151             : 
     152             : /* Find logical next and previous nodes in a tree */
     153             : extern struct rb_node *rb_next(struct rb_node *);
     154             : extern struct rb_node *rb_prev(struct rb_node *);
     155             : extern struct rb_node *rb_first(struct rb_root *);
     156             : extern struct rb_node *rb_last(struct rb_root *);
     157             : 
     158             : /* Postorder iteration - always visit the parent after its children */
     159             : extern struct rb_node *rb_first_postorder(const struct rb_root *);
     160             : extern struct rb_node *rb_next_postorder(const struct rb_node *);
     161             : 
     162             : #define rb_entry_safe(ptr, type, member) \
     163             :         ({ typeof(ptr) ____ptr = (ptr); \
     164             :            ____ptr ? rb_entry(____ptr, type, member) : NULL; \
     165             :         })
     166             : 
     167             : /**
     168             :  * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of
     169             :  * given type allowing the backing memory of @pos to be invalidated
     170             :  *
     171             :  * @pos:        the 'type *' to use as a loop cursor.
     172             :  * @n:          another 'type *' to use as temporary storage
     173             :  * @root:       'rb_root *' of the rbtree.
     174             :  * @field:      the name of the rb_node field within 'type'.
     175             :  *
     176             :  * rbtree_postorder_for_each_entry_safe() provides a similar guarantee as
     177             :  * list_for_each_entry_safe() and allows the iteration to continue independent
     178             :  * of changes to @pos by the body of the loop.
     179             :  *
     180             :  * Note, however, that it cannot handle other modifications that re-order the
     181             :  * rbtree it is iterating over. This includes calling rb_erase() on @pos, as
     182             :  * rb_erase() may rebalance the tree, causing us to miss some nodes.
     183             :  */
     184             : #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
     185             :         for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
     186             :              pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
     187             :                         typeof(*pos), field); 1; }); \
     188             :              pos = n)
     189             : 
     190             : /* Fast replacement of a single node without remove/rebalance/add/rebalance */
     191             : extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
     192             :                             struct rb_root *root);
     193             : 
     194             : static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
     195             :                                 struct rb_node ** rb_link)
     196             : {
     197  2814638130 :         node->rb_parent_color = (unsigned long )parent;
     198  2814638130 :         node->rb_left = node->rb_right = NULL;
     199             : 
     200  2814638130 :         *rb_link = node;
     201             : }
     202             : 
     203             : #endif  /* _LINUX_RBTREE_H */

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