libosmocore  0.9.3
Osmocom core library
include/osmocom/core/linuxrbtree.h
00001 /*
00002   Red Black Trees
00003   (C) 1999  Andrea Arcangeli <andrea@suse.de>
00004   
00005   This program is free software; you can redistribute it and/or modify
00006   it under the terms of the GNU General Public License as published by
00007   the Free Software Foundation; either version 2 of the License, or
00008   (at your option) any later version.
00009 
00010   This program is distributed in the hope that it will be useful,
00011   but WITHOUT ANY WARRANTY; without even the implied warranty of
00012   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00013   GNU General Public License for more details.
00014 
00015   You should have received a copy of the GNU General Public License
00016   along with this program; if not, write to the Free Software
00017   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00018 
00019   linux/include/linux/rbtree.h
00020 
00021   To use rbtrees you'll have to implement your own insert and search cores.
00022   This will avoid us to use callbacks and to drop drammatically performances.
00023   I know it's not the cleaner way,  but in C (not in C++) to get
00024   performances and genericity...
00025 
00026   Some example of insert and search follows here. The search is a plain
00027   normal search over an ordered tree. The insert instead must be implemented
00028   int two steps: as first thing the code must insert the element in
00029   order as a red leaf in the tree, then the support library function
00030   rb_insert_color() must be called. Such function will do the
00031   not trivial work to rebalance the rbtree if necessary.
00032 
00033 -----------------------------------------------------------------------
00034 static inline struct page * rb_search_page_cache(struct inode * inode,
00035                                                  unsigned long offset)
00036 {
00037         struct rb_node * n = inode->i_rb_page_cache.rb_node;
00038         struct page * page;
00039 
00040         while (n)
00041         {
00042                 page = rb_entry(n, struct page, rb_page_cache);
00043 
00044                 if (offset < page->offset)
00045                         n = n->rb_left;
00046                 else if (offset > page->offset)
00047                         n = n->rb_right;
00048                 else
00049                         return page;
00050         }
00051         return NULL;
00052 }
00053 
00054 static inline struct page * __rb_insert_page_cache(struct inode * inode,
00055                                                    unsigned long offset,
00056                                                    struct rb_node * node)
00057 {
00058         struct rb_node ** p = &inode->i_rb_page_cache.rb_node;
00059         struct rb_node * parent = NULL;
00060         struct page * page;
00061 
00062         while (*p)
00063         {
00064                 parent = *p;
00065                 page = rb_entry(parent, struct page, rb_page_cache);
00066 
00067                 if (offset < page->offset)
00068                         p = &(*p)->rb_left;
00069                 else if (offset > page->offset)
00070                         p = &(*p)->rb_right;
00071                 else
00072                         return page;
00073         }
00074 
00075         rb_link_node(node, parent, p);
00076 
00077         return NULL;
00078 }
00079 
00080 static inline struct page * rb_insert_page_cache(struct inode * inode,
00081                                                  unsigned long offset,
00082                                                  struct rb_node * node)
00083 {
00084         struct page * ret;
00085         if ((ret = __rb_insert_page_cache(inode, offset, node)))
00086                 goto out;
00087         rb_insert_color(node, &inode->i_rb_page_cache);
00088  out:
00089         return ret;
00090 }
00091 -----------------------------------------------------------------------
00092 */
00093 
00094 #pragma once
00095 
00096 #include <stdlib.h>
00097 
00098 struct rb_node
00099 {
00100         unsigned long  rb_parent_color;
00101 #define RB_RED          0
00102 #define RB_BLACK        1
00103         struct rb_node *rb_right;
00104         struct rb_node *rb_left;
00105 } __attribute__((aligned(sizeof(long))));
00106     /* The alignment might seem pointless, but allegedly CRIS needs it */
00107 
00108 struct rb_root
00109 {
00110         struct rb_node *rb_node;
00111 };
00112 
00113 
00114 #define rb_parent(r)   ((struct rb_node *)((r)->rb_parent_color & ~3))
00115 #define rb_color(r)   ((r)->rb_parent_color & 1)
00116 #define rb_is_red(r)   (!rb_color(r))
00117 #define rb_is_black(r) rb_color(r)
00118 #define rb_set_red(r)  do { (r)->rb_parent_color &= ~1; } while (0)
00119 #define rb_set_black(r)  do { (r)->rb_parent_color |= 1; } while (0)
00120 
00121 static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
00122 {
00123         rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p;
00124 }
00125 static inline void rb_set_color(struct rb_node *rb, int color)
00126 {
00127         rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
00128 }
00129 
00130 #define RB_ROOT { NULL, }
00131 #define rb_entry(ptr, type, member) container_of(ptr, type, member)
00132 
00133 #define RB_EMPTY_ROOT(root)     ((root)->rb_node == NULL)
00134 #define RB_EMPTY_NODE(node)     (rb_parent(node) == node)
00135 #define RB_CLEAR_NODE(node)     (rb_set_parent(node, node))
00136 
00137 extern void rb_insert_color(struct rb_node *, struct rb_root *);
00138 extern void rb_erase(struct rb_node *, struct rb_root *);
00139 
00140 /* Find logical next and previous nodes in a tree */
00141 extern struct rb_node *rb_next(const struct rb_node *);
00142 extern struct rb_node *rb_prev(const struct rb_node *);
00143 extern struct rb_node *rb_first(const struct rb_root *);
00144 extern struct rb_node *rb_last(const struct rb_root *);
00145 
00146 /* Fast replacement of a single node without remove/rebalance/add/rebalance */
00147 extern void rb_replace_node(struct rb_node *victim, struct rb_node *_new, 
00148                             struct rb_root *root);
00149 
00150 static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
00151                                 struct rb_node ** rb_link)
00152 {
00153         node->rb_parent_color = (unsigned long )parent;
00154         node->rb_left = node->rb_right = NULL;
00155 
00156         *rb_link = node;
00157 }