1 /* 2 Red Black Trees 3 (C) 1999 Andrea Arcangeli <[email protected]> 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 #include <linux/rcupdate.h> 35 36 struct rb_node { 37 unsigned long __rb_parent_color; 38 struct rb_node *rb_right; 39 struct rb_node *rb_left; 40 } __attribute__((aligned(sizeof(long)))); 41 /* The alignment might seem pointless, but allegedly CRIS needs it */ 42 43 struct rb_root { 44 struct rb_node *rb_node; 45 }; 46 47 48 #define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3)) 49 50 #define RB_ROOT (struct rb_root) { NULL, } 51 #define rb_entry(ptr, type, member) container_of(ptr, type, member) 52 53 #define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL) 54 55 /* 'empty' nodes are nodes that are known not to be inserted in an rbtree */ 56 #define RB_EMPTY_NODE(node) \ 57 ((node)->__rb_parent_color == (unsigned long)(node)) 58 #define RB_CLEAR_NODE(node) \ 59 ((node)->__rb_parent_color = (unsigned long)(node)) 60 61 62 extern void rb_insert_color(struct rb_node *, struct rb_root *); 63 extern void rb_erase(struct rb_node *, struct rb_root *); 64 65 66 /* Find logical next and previous nodes in a tree */ 67 extern struct rb_node *rb_next(const struct rb_node *); 68 extern struct rb_node *rb_prev(const struct rb_node *); 69 extern struct rb_node *rb_first(const struct rb_root *); 70 extern struct rb_node *rb_last(const struct rb_root *); 71 72 /* Postorder iteration - always visit the parent after its children */ 73 extern struct rb_node *rb_first_postorder(const struct rb_root *); 74 extern struct rb_node *rb_next_postorder(const struct rb_node *); 75 76 /* Fast replacement of a single node without remove/rebalance/add/rebalance */ 77 extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, 78 struct rb_root *root); 79 80 static inline void rb_link_node(struct rb_node *node, struct rb_node *parent, 81 struct rb_node **rb_link) 82 { 83 node->__rb_parent_color = (unsigned long)parent; 84 node->rb_left = node->rb_right = NULL; 85 86 *rb_link = node; 87 } 88 89 static inline void rb_link_node_rcu(struct rb_node *node, struct rb_node *parent, 90 struct rb_node **rb_link) 91 { 92 node->__rb_parent_color = (unsigned long)parent; 93 node->rb_left = node->rb_right = NULL; 94 95 rcu_assign_pointer(*rb_link, node); 96 } 97 98 #define rb_entry_safe(ptr, type, member) \ 99 ({ typeof(ptr) ____ptr = (ptr); \ 100 ____ptr ? rb_entry(____ptr, type, member) : NULL; \ 101 }) 102 103 /** 104 * rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of 105 * given type safe against removal of rb_node entry 106 * 107 * @pos: the 'type *' to use as a loop cursor. 108 * @n: another 'type *' to use as temporary storage 109 * @root: 'rb_root *' of the rbtree. 110 * @field: the name of the rb_node field within 'type'. 111 */ 112 #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \ 113 for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \ 114 pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \ 115 typeof(*pos), field); 1; }); \ 116 pos = n) 117 118 #endif /* _LINUX_RBTREE_H */ 119