include/linux/prio_tree.h

   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
  14 struct raw_prio_tree_node {
  15         struct prio_tree_node   *left;
  16         struct prio_tree_node   *right;
  17         struct prio_tree_node   *parent;
  18 };
  19
  20 struct 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
  28 struct 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
  38 struct 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
  49 static 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)        \
  59 do {                                    \
  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)                                \
  69 do {                                                            \
  70         (ptr)->left = (ptr)->right = (ptr)->parent = (ptr);     \
  71 } while (0)
  72
  73 #define INIT_PRIO_TREE_ITER(ptr)        \
  74 do {                                    \
  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
  84 static inline int prio_tree_empty(const struct prio_tree_root *root)
  85 {
  86         return root->prio_tree_node == NULL;
  87 }
  88
  89 static inline int prio_tree_root(const struct prio_tree_node *node)
  90 {
  91         return node->parent == node;
  92 }
  93
  94 static inline int prio_tree_left_empty(const struct prio_tree_node *node)
  95 {
  96         return node->left == node;
  97 }
  98
  99 static inline int prio_tree_right_empty(const struct prio_tree_node *node)
 100 {
 101         return node->right == node;
 102 }
 103
 104
 105 struct prio_tree_node *prio_tree_replace(struct prio_tree_root *root,
 106                 struct prio_tree_node *old, struct prio_tree_node *node);
 107 struct prio_tree_node *prio_tree_insert(struct prio_tree_root *root,
 108                 struct prio_tree_node *node);
 109 void prio_tree_remove(struct prio_tree_root *root, struct prio_tree_node *node);
 110 struct 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 */