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 __TOOLS_LINUX_PERF_RBTREE_H 30 #define __TOOLS_LINUX_PERF_RBTREE_H 31 32 #include <linux/kernel.h> 33 #include <linux/stddef.h> 34 35 struct rb_node { 36 unsigned long __rb_parent_color; 37 struct rb_node *rb_right; 38 struct rb_node *rb_left; 39 } __attribute__((aligned(sizeof(long)))); 40 /* The alignment might seem pointless, but allegedly CRIS needs it */ 41 42 struct rb_root { 43 struct rb_node *rb_node; 44 }; 45 46 /* 47 * Leftmost-cached rbtrees. 48 * 49 * We do not cache the rightmost node based on footprint 50 * size vs number of potential users that could benefit 51 * from O(1) rb_last(). Just not worth it, users that want 52 * this feature can always implement the logic explicitly. 53 * Furthermore, users that want to cache both pointers may 54 * find it a bit asymmetric, but that's ok. 55 */ 56 struct rb_root_cached { 57 struct rb_root rb_root; 58 struct rb_node *rb_leftmost; 59 }; 60 61 #define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3)) 62 63 #define RB_ROOT (struct rb_root) { NULL, } 64 #define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL } 65 #define rb_entry(ptr, type, member) container_of(ptr, type, member) 66 67 #define RB_EMPTY_ROOT(root) (READ_ONCE((root)->rb_node) == NULL) 68 69 /* 'empty' nodes are nodes that are known not to be inserted in an rbtree */ 70 #define RB_EMPTY_NODE(node) \ 71 ((node)->__rb_parent_color == (unsigned long)(node)) 72 #define RB_CLEAR_NODE(node) \ 73 ((node)->__rb_parent_color = (unsigned long)(node)) 74 75 76 extern void rb_insert_color(struct rb_node *, struct rb_root *); 77 extern void rb_erase(struct rb_node *, struct rb_root *); 78 79 80 /* Find logical next and previous nodes in a tree */ 81 extern struct rb_node *rb_next(const struct rb_node *); 82 extern struct rb_node *rb_prev(const struct rb_node *); 83 extern struct rb_node *rb_first(const struct rb_root *); 84 extern struct rb_node *rb_last(const struct rb_root *); 85 86 extern void rb_insert_color_cached(struct rb_node *, 87 struct rb_root_cached *, bool); 88 extern void rb_erase_cached(struct rb_node *node, struct rb_root_cached *); 89 /* Same as rb_first(), but O(1) */ 90 #define rb_first_cached(root) (root)->rb_leftmost 91 92 /* Postorder iteration - always visit the parent after its children */ 93 extern struct rb_node *rb_first_postorder(const struct rb_root *); 94 extern struct rb_node *rb_next_postorder(const struct rb_node *); 95 96 /* Fast replacement of a single node without remove/rebalance/add/rebalance */ 97 extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, 98 struct rb_root *root); 99 extern void rb_replace_node_cached(struct rb_node *victim, struct rb_node *new, 100 struct rb_root_cached *root); 101 102 static inline void rb_link_node(struct rb_node *node, struct rb_node *parent, 103 struct rb_node **rb_link) 104 { 105 node->__rb_parent_color = (unsigned long)parent; 106 node->rb_left = node->rb_right = NULL; 107 108 *rb_link = node; 109 } 110 111 #define rb_entry_safe(ptr, type, member) \ 112 ({ typeof(ptr) ____ptr = (ptr); \ 113 ____ptr ? rb_entry(____ptr, type, member) : NULL; \ 114 }) 115 116 /** 117 * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of 118 * given type allowing the backing memory of @pos to be invalidated 119 * 120 * @pos: the 'type *' to use as a loop cursor. 121 * @n: another 'type *' to use as temporary storage 122 * @root: 'rb_root *' of the rbtree. 123 * @field: the name of the rb_node field within 'type'. 124 * 125 * rbtree_postorder_for_each_entry_safe() provides a similar guarantee as 126 * list_for_each_entry_safe() and allows the iteration to continue independent 127 * of changes to @pos by the body of the loop. 128 * 129 * Note, however, that it cannot handle other modifications that re-order the 130 * rbtree it is iterating over. This includes calling rb_erase() on @pos, as 131 * rb_erase() may rebalance the tree, causing us to miss some nodes. 132 */ 133 #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \ 134 for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \ 135 pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \ 136 typeof(*pos), field); 1; }); \ 137 pos = n) 138 139 static inline void rb_erase_init(struct rb_node *n, struct rb_root *root) 140 { 141 rb_erase(n, root); 142 RB_CLEAR_NODE(n); 143 } 144 #endif /* __TOOLS_LINUX_PERF_RBTREE_H */ 145