diff options
Diffstat (limited to 'include/linux/rbtree.h')
| -rw-r--r-- | include/linux/rbtree.h | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h index d7db17996322..e0b300de8f3f 100644 --- a/include/linux/rbtree.h +++ b/include/linux/rbtree.h @@ -158,4 +158,194 @@ static inline void rb_replace_node_cached(struct rb_node *victim, rb_replace_node(victim, new, &root->rb_root); } +/* + * The below helper functions use 2 operators with 3 different + * calling conventions. The operators are related like: + * + * comp(a->key,b) < 0 := less(a,b) + * comp(a->key,b) > 0 := less(b,a) + * comp(a->key,b) == 0 := !less(a,b) && !less(b,a) + * + * If these operators define a partial order on the elements we make no + * guarantee on which of the elements matching the key is found. See + * rb_find(). + * + * The reason for this is to allow the find() interface without requiring an + * on-stack dummy object, which might not be feasible due to object size. + */ + +/** + * rb_add_cached() - insert @node into the leftmost cached tree @tree + * @node: node to insert + * @tree: leftmost cached tree to insert @node into + * @less: operator defining the (partial) node order + */ +static __always_inline void +rb_add_cached(struct rb_node *node, struct rb_root_cached *tree, + bool (*less)(struct rb_node *, const struct rb_node *)) +{ + struct rb_node **link = &tree->rb_root.rb_node; + struct rb_node *parent = NULL; + bool leftmost = true; + + while (*link) { + parent = *link; + if (less(node, parent)) { + link = &parent->rb_left; + } else { + link = &parent->rb_right; + leftmost = false; + } + } + + rb_link_node(node, parent, link); + rb_insert_color_cached(node, tree, leftmost); +} + +/** + * rb_add() - insert @node into @tree + * @node: node to insert + * @tree: tree to insert @node into + * @less: operator defining the (partial) node order + */ +static __always_inline void +rb_add(struct rb_node *node, struct rb_root *tree, + bool (*less)(struct rb_node *, const struct rb_node *)) +{ + struct rb_node **link = &tree->rb_node; + struct rb_node *parent = NULL; + + while (*link) { + parent = *link; + if (less(node, parent)) + link = &parent->rb_left; + else + link = &parent->rb_right; + } + + rb_link_node(node, parent, link); + rb_insert_color(node, tree); +} + +/** + * rb_find_add() - find equivalent @node in @tree, or add @node + * @node: node to look-for / insert + * @tree: tree to search / modify + * @cmp: operator defining the node order + * + * Returns the rb_node matching @node, or NULL when no match is found and @node + * is inserted. + */ +static __always_inline struct rb_node * +rb_find_add(struct rb_node *node, struct rb_root *tree, + int (*cmp)(struct rb_node *, const struct rb_node *)) +{ + struct rb_node **link = &tree->rb_node; + struct rb_node *parent = NULL; + int c; + + while (*link) { + parent = *link; + c = cmp(node, parent); + + if (c < 0) + link = &parent->rb_left; + else if (c > 0) + link = &parent->rb_right; + else + return parent; + } + + rb_link_node(node, parent, link); + rb_insert_color(node, tree); + return NULL; +} + +/** + * rb_find() - find @key in tree @tree + * @key: key to match + * @tree: tree to search + * @cmp: operator defining the node order + * + * Returns the rb_node matching @key or NULL. + */ +static __always_inline struct rb_node * +rb_find(const void *key, const struct rb_root *tree, + int (*cmp)(const void *key, const struct rb_node *)) +{ + struct rb_node *node = tree->rb_node; + + while (node) { + int c = cmp(key, node); + + if (c < 0) + node = node->rb_left; + else if (c > 0) + node = node->rb_right; + else + return node; + } + + return NULL; +} + +/** + * rb_find_first() - find the first @key in @tree + * @key: key to match + * @tree: tree to search + * @cmp: operator defining node order + * + * Returns the leftmost node matching @key, or NULL. + */ +static __always_inline struct rb_node * +rb_find_first(const void *key, const struct rb_root *tree, + int (*cmp)(const void *key, const struct rb_node *)) +{ + struct rb_node *node = tree->rb_node; + struct rb_node *match = NULL; + + while (node) { + int c = cmp(key, node); + + if (c <= 0) { + if (!c) + match = node; + node = node->rb_left; + } else if (c > 0) { + node = node->rb_right; + } + } + + return match; +} + +/** + * rb_next_match() - find the next @key in @tree + * @key: key to match + * @tree: tree to search + * @cmp: operator defining node order + * + * Returns the next node matching @key, or NULL. + */ +static __always_inline struct rb_node * +rb_next_match(const void *key, struct rb_node *node, + int (*cmp)(const void *key, const struct rb_node *)) +{ + node = rb_next(node); + if (node && cmp(key, node)) + node = NULL; + return node; +} + +/** + * rb_for_each() - iterates a subtree matching @key + * @node: iterator + * @key: key to match + * @tree: tree to search + * @cmp: operator defining node order + */ +#define rb_for_each(node, key, tree, cmp) \ + for ((node) = rb_find_first((key), (tree), (cmp)); \ + (node); (node) = rb_next_match((key), (node), (cmp))) + #endif /* _LINUX_RBTREE_H */ |