linux/include/linux/prio_tree.h
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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 */
 121
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