/* * 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 #include #include #include /* * 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 */