1 /* 2 Red Black Trees 3 (C) 1999 Andrea Arcangeli <andrea@suse.de> 4 5 * SPDX-License-Identifier: GPL-2.0+ 6 7 linux/include/linux/rbtree.h 8 9 To use rbtrees you'll have to implement your own insert and search cores. 10 This will avoid us to use callbacks and to drop drammatically performances. 11 I know it's not the cleaner way, but in C (not in C++) to get 12 performances and genericity... 13 14 See Documentation/rbtree.txt for documentation and samples. 15 */ 16 17 #ifndef _LINUX_RBTREE_H 18 #define _LINUX_RBTREE_H 19 20 #ifndef __UBOOT__ 21 #include <linux/kernel.h> 22 #endif 23 #include <linux/stddef.h> 24 25 struct rb_node { 26 unsigned long __rb_parent_color; 27 struct rb_node *rb_right; 28 struct rb_node *rb_left; 29 } __attribute__((aligned(sizeof(long)))); 30 /* The alignment might seem pointless, but allegedly CRIS needs it */ 31 32 struct rb_root { 33 struct rb_node *rb_node; 34 }; 35 36 37 #define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3)) 38 39 #define RB_ROOT (struct rb_root) { NULL, } 40 #define rb_entry(ptr, type, member) container_of(ptr, type, member) 41 42 #define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL) 43 44 /* 'empty' nodes are nodes that are known not to be inserted in an rbree */ 45 #define RB_EMPTY_NODE(node) \ 46 ((node)->__rb_parent_color == (unsigned long)(node)) 47 #define RB_CLEAR_NODE(node) \ 48 ((node)->__rb_parent_color = (unsigned long)(node)) 49 50 51 extern void rb_insert_color(struct rb_node *, struct rb_root *); 52 extern void rb_erase(struct rb_node *, struct rb_root *); 53 54 55 /* Find logical next and previous nodes in a tree */ 56 extern struct rb_node *rb_next(const struct rb_node *); 57 extern struct rb_node *rb_prev(const struct rb_node *); 58 extern struct rb_node *rb_first(const struct rb_root *); 59 extern struct rb_node *rb_last(const struct rb_root *); 60 61 /* Postorder iteration - always visit the parent after its children */ 62 extern struct rb_node *rb_first_postorder(const struct rb_root *); 63 extern struct rb_node *rb_next_postorder(const struct rb_node *); 64 65 /* Fast replacement of a single node without remove/rebalance/add/rebalance */ 66 extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, 67 struct rb_root *root); 68 69 static inline void rb_link_node(struct rb_node * node, struct rb_node * parent, 70 struct rb_node ** rb_link) 71 { 72 node->__rb_parent_color = (unsigned long)parent; 73 node->rb_left = node->rb_right = NULL; 74 75 *rb_link = node; 76 } 77 78 #define rb_entry_safe(ptr, type, member) \ 79 ({ typeof(ptr) ____ptr = (ptr); \ 80 ____ptr ? rb_entry(____ptr, type, member) : NULL; \ 81 }) 82 83 /** 84 * rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of 85 * given type safe against removal of rb_node entry 86 * 87 * @pos: the 'type *' to use as a loop cursor. 88 * @n: another 'type *' to use as temporary storage 89 * @root: 'rb_root *' of the rbtree. 90 * @field: the name of the rb_node field within 'type'. 91 */ 92 #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \ 93 for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \ 94 pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \ 95 typeof(*pos), field); 1; }); \ 96 pos = n) 97 98 #endif /* _LINUX_RBTREE_H */ 99