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1#ifndef _LINUX_PRIO_TREE_H
2#define _LINUX_PRIO_TREE_H
3
4/*
5 * K&R 2nd ed. A8.3 somewhat obliquely hints that initial sequences of struct
6 * fields with identical types should end up at the same location. We'll use
7 * this until we can scrap struct raw_prio_tree_node.
8 *
9 * Note: all this could be done more elegantly by using unnamed union/struct
10 * fields. However, gcc 2.95.3 and apparently also gcc 3.0.4 don't support this
11 * language extension.
12 */
13
14struct raw_prio_tree_node {
15 struct prio_tree_node *left;
16 struct prio_tree_node *right;
17 struct prio_tree_node *parent;
18};
19
20struct prio_tree_node {
21 struct prio_tree_node *left;
22 struct prio_tree_node *right;
23 struct prio_tree_node *parent;
24 unsigned long start;
25 unsigned long last; /* last location _in_ interval */
26};
27
28struct prio_tree_root {
29 struct prio_tree_node *prio_tree_node;
30 unsigned short index_bits;
31 unsigned short raw;
32 /*
33 * 0: nodes are of type struct prio_tree_node
34 * 1: nodes are of type raw_prio_tree_node
35 */
36};
37
38struct prio_tree_iter {
39 struct prio_tree_node *cur;
40 unsigned long mask;
41 unsigned long value;
42 int size_level;
43
44 struct prio_tree_root *root;
45 pgoff_t r_index;
46 pgoff_t h_index;
47};
48
49static inline void prio_tree_iter_init(struct prio_tree_iter *iter,
50 struct prio_tree_root *root, pgoff_t r_index, pgoff_t h_index)
51{
52 iter->root = root;
53 iter->r_index = r_index;
54 iter->h_index = h_index;
55 iter->cur = NULL;
56}
57
58#define __INIT_PRIO_TREE_ROOT(ptr, _raw) \
59do { \
60 (ptr)->prio_tree_node = NULL; \
61 (ptr)->index_bits = 1; \
62 (ptr)->raw = (_raw); \
63} while (0)
64
65#define INIT_PRIO_TREE_ROOT(ptr) __INIT_PRIO_TREE_ROOT(ptr, 0)
66#define INIT_RAW_PRIO_TREE_ROOT(ptr) __INIT_PRIO_TREE_ROOT(ptr, 1)
67
68#define INIT_PRIO_TREE_NODE(ptr) \
69do { \
70 (ptr)->left = (ptr)->right = (ptr)->parent = (ptr); \
71} while (0)
72
73#define INIT_PRIO_TREE_ITER(ptr) \
74do { \
75 (ptr)->cur = NULL; \
76 (ptr)->mask = 0UL; \
77 (ptr)->value = 0UL; \
78 (ptr)->size_level = 0; \
79} while (0)
80
81#define prio_tree_entry(ptr, type, member) \
82 ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
83
84static inline int prio_tree_empty(const struct prio_tree_root *root)
85{
86 return root->prio_tree_node == NULL;
87}
88
89static inline int prio_tree_root(const struct prio_tree_node *node)
90{
91 return node->parent == node;
92}
93
94static inline int prio_tree_left_empty(const struct prio_tree_node *node)
95{
96 return node->left == node;
97}
98
99static inline int prio_tree_right_empty(const struct prio_tree_node *node)
100{
101 return node->right == node;
102}
103
104
105struct prio_tree_node *prio_tree_replace(struct prio_tree_root *root,
106 struct prio_tree_node *old, struct prio_tree_node *node);
107struct prio_tree_node *prio_tree_insert(struct prio_tree_root *root,
108 struct prio_tree_node *node);
109void prio_tree_remove(struct prio_tree_root *root, struct prio_tree_node *node);
110struct prio_tree_node *prio_tree_next(struct prio_tree_iter *iter);
111
112#define raw_prio_tree_replace(root, old, node) \
113 prio_tree_replace(root, (struct prio_tree_node *) (old), \
114 (struct prio_tree_node *) (node))
115#define raw_prio_tree_insert(root, node) \
116 prio_tree_insert(root, (struct prio_tree_node *) (node))
117#define raw_prio_tree_remove(root, node) \
118 prio_tree_remove(root, (struct prio_tree_node *) (node))
119
120#endif /* _LINUX_PRIO_TREE_H */