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Diffstat (limited to 'util/rbtree.h')
| -rw-r--r-- | util/rbtree.h | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/util/rbtree.h b/util/rbtree.h new file mode 100644 index 000000000000..879804dd8600 --- /dev/null +++ b/util/rbtree.h @@ -0,0 +1,192 @@ +/* + * rbtree.h -- generic red-black tree + * + * Copyright (c) 2001-2007, NLnet Labs. All rights reserved. + * + * This software is open source. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * 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. + * + * Neither the name of the NLNET LABS nor the names of its contributors may + * be used to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "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 REGENTS OR CONTRIBUTORS 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. + * + */ + +/** + * \file + * Red black tree. Implementation taken from NSD 3.0.5, adjusted for use + * in unbound (memory allocation, logging and so on). + */ + +#ifndef UTIL_RBTREE_H_ +#define UTIL_RBTREE_H_ + +/** + * This structure must be the first member of the data structure in + * the rbtree. This allows easy casting between an rbnode_t and the + * user data (poor man's inheritance). + */ +typedef struct rbnode_t rbnode_t; +/** + * The rbnode_t struct definition. + */ +struct rbnode_t { + /** parent in rbtree, RBTREE_NULL for root */ + rbnode_t *parent; + /** left node (smaller items) */ + rbnode_t *left; + /** right node (larger items) */ + rbnode_t *right; + /** pointer to sorting key */ + const void *key; + /** colour of this node */ + uint8_t color; +}; + +/** The nullpointer, points to empty node */ +#define RBTREE_NULL &rbtree_null_node +/** the global empty node */ +extern rbnode_t rbtree_null_node; + +/** An entire red black tree */ +typedef struct rbtree_t rbtree_t; +/** definition for tree struct */ +struct rbtree_t { + /** The root of the red-black tree */ + rbnode_t *root; + + /** The number of the nodes in the tree */ + size_t count; + + /** + * Key compare function. <0,0,>0 like strcmp. + * Return 0 on two NULL ptrs. + */ + int (*cmp) (const void *, const void *); +}; + +/** + * Create new tree (malloced) with given key compare function. + * @param cmpf: compare function (like strcmp) takes pointers to two keys. + * @return: new tree, empty. + */ +rbtree_t *rbtree_create(int (*cmpf)(const void *, const void *)); + +/** + * Init a new tree (malloced by caller) with given key compare function. + * @param rbtree: uninitialised memory for new tree, returned empty. + * @param cmpf: compare function (like strcmp) takes pointers to two keys. + */ +void rbtree_init(rbtree_t *rbtree, int (*cmpf)(const void *, const void *)); + +/** + * Insert data into the tree. + * @param rbtree: tree to insert to. + * @param data: element to insert. + * @return: data ptr or NULL if key already present. + */ +rbnode_t *rbtree_insert(rbtree_t *rbtree, rbnode_t *data); + +/** + * Delete element from tree. + * @param rbtree: tree to delete from. + * @param key: key of item to delete. + * @return: node that is now unlinked from the tree. User to delete it. + * returns 0 if node not present + */ +rbnode_t *rbtree_delete(rbtree_t *rbtree, const void *key); + +/** + * Find key in tree. Returns NULL if not found. + * @param rbtree: tree to find in. + * @param key: key that must match. + * @return: node that fits or NULL. + */ +rbnode_t *rbtree_search(rbtree_t *rbtree, const void *key); + +/** + * Find, but match does not have to be exact. + * @param rbtree: tree to find in. + * @param key: key to find position of. + * @param result: set to the exact node if present, otherwise to element that + * precedes the position of key in the tree. NULL if no smaller element. + * @return: true if exact match in result. Else result points to <= element, + * or NULL if key is smaller than the smallest key. + */ +int rbtree_find_less_equal(rbtree_t *rbtree, const void *key, + rbnode_t **result); + +/** + * Returns first (smallest) node in the tree + * @param rbtree: tree + * @return: smallest element or NULL if tree empty. + */ +rbnode_t *rbtree_first(rbtree_t *rbtree); + +/** + * Returns last (largest) node in the tree + * @param rbtree: tree + * @return: largest element or NULL if tree empty. + */ +rbnode_t *rbtree_last(rbtree_t *rbtree); + +/** + * Returns next larger node in the tree + * @param rbtree: tree + * @return: next larger element or NULL if no larger in tree. + */ +rbnode_t *rbtree_next(rbnode_t *rbtree); + +/** + * Returns previous smaller node in the tree + * @param rbtree: tree + * @return: previous smaller element or NULL if no previous in tree. + */ +rbnode_t *rbtree_previous(rbnode_t *rbtree); + +/** + * Call with node=variable of struct* with rbnode_t as first element. + * with type is the type of a pointer to that struct. + */ +#define RBTREE_FOR(node, type, rbtree) \ + for(node=(type)rbtree_first(rbtree); \ + (rbnode_t*)node != RBTREE_NULL; \ + node = (type)rbtree_next((rbnode_t*)node)) + +/** + * Call function for all elements in the redblack tree, such that + * leaf elements are called before parent elements. So that all + * elements can be safely free()d. + * Note that your function must not remove the nodes from the tree. + * Since that may trigger rebalances of the rbtree. + * @param tree: the tree + * @param func: function called with element and user arg. + * The function must not alter the rbtree. + * @param arg: user argument. + */ +void traverse_postorder(rbtree_t* tree, void (*func)(rbnode_t*, void*), + void* arg); + +#endif /* UTIL_RBTREE_H_ */ |