rbtree.h 3.1 KB

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