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Diffstat (limited to 'kern/rbtree.h')
| -rw-r--r-- | kern/rbtree.h | 306 |
1 files changed, 306 insertions, 0 deletions
diff --git a/kern/rbtree.h b/kern/rbtree.h new file mode 100644 index 0000000..f885fe7 --- /dev/null +++ b/kern/rbtree.h @@ -0,0 +1,306 @@ +/* + * Copyright (c) 2010, 2011 Richard Braun. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * + * Red-black tree. + */ + +#ifndef _KERN_RBTREE_H +#define _KERN_RBTREE_H + +#include <stddef.h> +#include <kern/assert.h> +#include <kern/macros.h> +#include <sys/types.h> + +/* + * Indexes of the left and right nodes in the children array of a node. + */ +#define RBTREE_LEFT 0 +#define RBTREE_RIGHT 1 + +/* + * Red-black node. + */ +struct rbtree_node; + +/* + * Red-black tree. + */ +struct rbtree; + +/* + * Static tree initializer. + */ +#define RBTREE_INITIALIZER { NULL } + +#include "rbtree_i.h" + +/* + * Initialize a tree. + */ +static inline void rbtree_init(struct rbtree *tree) +{ + tree->root = NULL; +} + +/* + * Initialize a node. + * + * A node is in no tree when its parent points to itself. + */ +static inline void rbtree_node_init(struct rbtree_node *node) +{ + assert(rbtree_check_alignment(node)); + + node->parent = (unsigned long)node | RBTREE_COLOR_RED; + node->children[RBTREE_LEFT] = NULL; + node->children[RBTREE_RIGHT] = NULL; +} + +/* + * Return true if node is in no tree. + */ +static inline int rbtree_node_unlinked(const struct rbtree_node *node) +{ + return rbtree_parent(node) == node; +} + +/* + * Macro that evaluates to the address of the structure containing the + * given node based on the given type and member. + */ +#define rbtree_entry(node, type, member) structof(node, type, member) + +/* + * Return true if tree is empty. + */ +static inline int rbtree_empty(const struct rbtree *tree) +{ + return tree->root == NULL; +} + +/* + * Look up a node in a tree. + * + * Note that implementing the lookup algorithm as a macro gives two benefits: + * First, it avoids the overhead of a callback function. Next, the type of the + * cmp_fn parameter isn't rigid. The only guarantee offered by this + * implementation is that the key parameter is the first parameter given to + * cmp_fn. This way, users can pass only the value they need for comparison + * instead of e.g. allocating a full structure on the stack. + * + * See rbtree_insert(). + */ +#define rbtree_lookup(tree, key, cmp_fn) \ +MACRO_BEGIN \ + struct rbtree_node *___cur; \ + int ___diff; \ + \ + ___cur = (tree)->root; \ + \ + while (___cur != NULL) { \ + ___diff = cmp_fn(key, ___cur); \ + \ + if (___diff == 0) \ + break; \ + \ + ___cur = ___cur->children[rbtree_d2i(___diff)]; \ + } \ + \ + ___cur; \ +MACRO_END + +/* + * Look up a node or one of its nearest nodes in a tree. + * + * This macro essentially acts as rbtree_lookup() but if no entry matched + * the key, an additional step is performed to obtain the next or previous + * node, depending on the direction (left or right). + * + * The constraints that apply to the key parameter are the same as for + * rbtree_lookup(). + */ +#define rbtree_lookup_nearest(tree, key, cmp_fn, dir) \ +MACRO_BEGIN \ + struct rbtree_node *___cur, *___prev; \ + int ___diff, ___index; \ + \ + ___prev = NULL; \ + ___index = -1; \ + ___cur = (tree)->root; \ + \ + while (___cur != NULL) { \ + ___diff = cmp_fn(key, ___cur); \ + \ + if (___diff == 0) \ + break; \ + \ + ___prev = ___cur; \ + ___index = rbtree_d2i(___diff); \ + ___cur = ___cur->children[___index]; \ + } \ + \ + if (___cur == NULL) \ + ___cur = rbtree_nearest(___prev, ___index, dir); \ + \ + ___cur; \ +MACRO_END + +/* + * Insert a node in a tree. + * + * This macro performs a standard lookup to obtain the insertion point of + * the given node in the tree (it is assumed that the inserted node never + * compares equal to any other entry in the tree) and links the node. It + * then checks red-black rules violations, and rebalances the tree if + * necessary. + * + * Unlike rbtree_lookup(), the cmp_fn parameter must compare two complete + * entries, so it is suggested to use two different comparison inline + * functions, such as myobj_cmp_lookup() and myobj_cmp_insert(). There is no + * guarantee about the order of the nodes given to the comparison function. + * + * See rbtree_lookup(). + */ +#define rbtree_insert(tree, node, cmp_fn) \ +MACRO_BEGIN \ + struct rbtree_node *___cur, *___prev; \ + int ___diff, ___index; \ + \ + ___prev = NULL; \ + ___index = -1; \ + ___cur = (tree)->root; \ + \ + while (___cur != NULL) { \ + ___diff = cmp_fn(node, ___cur); \ + assert(___diff != 0); \ + ___prev = ___cur; \ + ___index = rbtree_d2i(___diff); \ + ___cur = ___cur->children[___index]; \ + } \ + \ + rbtree_insert_rebalance(tree, ___prev, ___index, node); \ +MACRO_END + +/* + * Look up a node/slot pair in a tree. + * + * This macro essentially acts as rbtree_lookup() but in addition to a node, + * it also returns a slot, which identifies an insertion point in the tree. + * If the returned node is null, the slot can be used by rbtree_insert_slot() + * to insert without the overhead of an additional lookup. The slot is a + * simple unsigned long integer. + * + * The constraints that apply to the key parameter are the same as for + * rbtree_lookup(). + */ +#define rbtree_lookup_slot(tree, key, cmp_fn, slot) \ +MACRO_BEGIN \ + struct rbtree_node *___cur, *___prev; \ + int ___diff, ___index; \ + \ + ___prev = NULL; \ + ___index = 0; \ + ___cur = (tree)->root; \ + \ + while (___cur != NULL) { \ + ___diff = cmp_fn(key, ___cur); \ + \ + if (___diff == 0) \ + break; \ + \ + ___prev = ___cur; \ + ___index = rbtree_d2i(___diff); \ + ___cur = ___cur->children[___index]; \ + } \ + \ + (slot) = rbtree_slot(___prev, ___index); \ + ___cur; \ +MACRO_END + +/* + * Insert a node at an insertion point in a tree. + * + * This macro essentially acts as rbtree_insert() except that it doesn't + * obtain the insertion point with a standard lookup. The insertion point + * is obtained by calling rbtree_lookup_slot(). In addition, the new node + * must not compare equal to an existing node in the tree (i.e. the slot + * must denote a null node). + */ +static inline void +rbtree_insert_slot(struct rbtree *tree, unsigned long slot, + struct rbtree_node *node) +{ + struct rbtree_node *parent; + int index; + + parent = rbtree_slot_parent(slot); + index = rbtree_slot_index(slot); + rbtree_insert_rebalance(tree, parent, index, node); +} + +/* + * Remove a node from a tree. + * + * After completion, the node is stale. + */ +void rbtree_remove(struct rbtree *tree, struct rbtree_node *node); + +/* + * Return the first node of a tree. + */ +#define rbtree_first(tree) rbtree_firstlast(tree, RBTREE_LEFT) + +/* + * Return the last node of a tree. + */ +#define rbtree_last(tree) rbtree_firstlast(tree, RBTREE_RIGHT) + +/* + * Return the node previous to the given node. + */ +#define rbtree_prev(node) rbtree_walk(node, RBTREE_LEFT) + +/* + * Return the node next to the given node. + */ +#define rbtree_next(node) rbtree_walk(node, RBTREE_RIGHT) + +/* + * Forge a loop to process all nodes of a tree, removing them when visited. + * + * This macro can only be used to destroy a tree, so that the resources used + * by the entries can be released by the user. It basically removes all nodes + * without doing any color checking. + * + * After completion, all nodes and the tree root member are stale. + */ +#define rbtree_for_each_remove(tree, node, tmp) \ +for (node = rbtree_postwalk_deepest(tree), \ + tmp = rbtree_postwalk_unlink(node); \ + node != NULL; \ + node = tmp, tmp = rbtree_postwalk_unlink(node)) + +#endif /* _KERN_RBTREE_H */ |