193 lines
6.1 KiB
C
193 lines
6.1 KiB
C
/*
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* rbtree.h -- generic red-black tree
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*
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* Copyright (c) 2001-2007, NLnet Labs. All rights reserved.
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*
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* This software is open source.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* Neither the name of the NLNET LABS nor the names of its contributors may
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* be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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/**
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* \file
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* Red black tree. Implementation taken from NSD 3.0.5, adjusted for use
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* in unbound (memory allocation, logging and so on).
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*/
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#ifndef UTIL_RBTREE_H_
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#define UTIL_RBTREE_H_
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/**
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* This structure must be the first member of the data structure in
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* the rbtree. This allows easy casting between an rbnode_t and the
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* user data (poor man's inheritance).
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*/
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typedef struct rbnode_t rbnode_t;
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/**
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* The rbnode_t struct definition.
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*/
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struct rbnode_t {
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/** parent in rbtree, RBTREE_NULL for root */
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rbnode_t *parent;
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/** left node (smaller items) */
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rbnode_t *left;
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/** right node (larger items) */
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rbnode_t *right;
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/** pointer to sorting key */
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const void *key;
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/** colour of this node */
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uint8_t color;
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};
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/** The nullpointer, points to empty node */
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#define RBTREE_NULL &rbtree_null_node
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/** the global empty node */
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extern rbnode_t rbtree_null_node;
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/** An entire red black tree */
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typedef struct rbtree_t rbtree_t;
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/** definition for tree struct */
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struct rbtree_t {
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/** The root of the red-black tree */
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rbnode_t *root;
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/** The number of the nodes in the tree */
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size_t count;
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/**
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* Key compare function. <0,0,>0 like strcmp.
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* Return 0 on two NULL ptrs.
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*/
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int (*cmp) (const void *, const void *);
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};
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/**
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* Create new tree (malloced) with given key compare function.
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* @param cmpf: compare function (like strcmp) takes pointers to two keys.
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* @return: new tree, empty.
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*/
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rbtree_t *rbtree_create(int (*cmpf)(const void *, const void *));
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/**
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* Init a new tree (malloced by caller) with given key compare function.
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* @param rbtree: uninitialised memory for new tree, returned empty.
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* @param cmpf: compare function (like strcmp) takes pointers to two keys.
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*/
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void rbtree_init(rbtree_t *rbtree, int (*cmpf)(const void *, const void *));
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/**
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* Insert data into the tree.
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* @param rbtree: tree to insert to.
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* @param data: element to insert.
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* @return: data ptr or NULL if key already present.
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*/
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rbnode_t *rbtree_insert(rbtree_t *rbtree, rbnode_t *data);
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/**
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* Delete element from tree.
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* @param rbtree: tree to delete from.
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* @param key: key of item to delete.
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* @return: node that is now unlinked from the tree. User to delete it.
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* returns 0 if node not present
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*/
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rbnode_t *rbtree_delete(rbtree_t *rbtree, const void *key);
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/**
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* Find key in tree. Returns NULL if not found.
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* @param rbtree: tree to find in.
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* @param key: key that must match.
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* @return: node that fits or NULL.
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*/
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rbnode_t *rbtree_search(rbtree_t *rbtree, const void *key);
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/**
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* Find, but match does not have to be exact.
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* @param rbtree: tree to find in.
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* @param key: key to find position of.
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* @param result: set to the exact node if present, otherwise to element that
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* precedes the position of key in the tree. NULL if no smaller element.
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* @return: true if exact match in result. Else result points to <= element,
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* or NULL if key is smaller than the smallest key.
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*/
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int rbtree_find_less_equal(rbtree_t *rbtree, const void *key,
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rbnode_t **result);
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/**
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* Returns first (smallest) node in the tree
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* @param rbtree: tree
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* @return: smallest element or NULL if tree empty.
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*/
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rbnode_t *rbtree_first(rbtree_t *rbtree);
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/**
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* Returns last (largest) node in the tree
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* @param rbtree: tree
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* @return: largest element or NULL if tree empty.
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*/
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rbnode_t *rbtree_last(rbtree_t *rbtree);
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/**
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* Returns next larger node in the tree
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* @param rbtree: tree
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* @return: next larger element or NULL if no larger in tree.
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*/
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rbnode_t *rbtree_next(rbnode_t *rbtree);
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/**
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* Returns previous smaller node in the tree
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* @param rbtree: tree
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* @return: previous smaller element or NULL if no previous in tree.
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*/
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rbnode_t *rbtree_previous(rbnode_t *rbtree);
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/**
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* Call with node=variable of struct* with rbnode_t as first element.
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* with type is the type of a pointer to that struct.
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*/
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#define RBTREE_FOR(node, type, rbtree) \
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for(node=(type)rbtree_first(rbtree); \
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(rbnode_t*)node != RBTREE_NULL; \
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node = (type)rbtree_next((rbnode_t*)node))
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/**
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* Call function for all elements in the redblack tree, such that
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* leaf elements are called before parent elements. So that all
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* elements can be safely free()d.
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* Note that your function must not remove the nodes from the tree.
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* Since that may trigger rebalances of the rbtree.
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* @param tree: the tree
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* @param func: function called with element and user arg.
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* The function must not alter the rbtree.
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* @param arg: user argument.
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*/
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void traverse_postorder(rbtree_t* tree, void (*func)(rbnode_t*, void*),
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void* arg);
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#endif /* UTIL_RBTREE_H_ */
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