/*
* 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 COPYRIGHT
* HOLDER 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_type and the
* user data (poor man's inheritance).
*/
typedef struct rbnode_type rbnode_type;
/**
* The rbnode_type struct definition.
*/
struct rbnode_type {
/** parent in rbtree, RBTREE_NULL for root */
rbnode_type *parent;
/** left node (smaller items) */
rbnode_type *left;
/** right node (larger items) */
rbnode_type *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_type rbtree_null_node;
/** An entire red black tree */
typedef struct rbtree_type rbtree_type;
/** definition for tree struct */
struct rbtree_type {
/** The root of the red-black tree */
rbnode_type *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_type *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_type *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_type *rbtree_insert(rbtree_type *rbtree, rbnode_type *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_type *rbtree_delete(rbtree_type *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_type *rbtree_search(rbtree_type *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_type *rbtree, const void *key,
rbnode_type **result);
/**
* Returns first (smallest) node in the tree
* @param rbtree: tree
* @return: smallest element or NULL if tree empty.
*/
rbnode_type *rbtree_first(rbtree_type *rbtree);
/**
* Returns last (largest) node in the tree
* @param rbtree: tree
* @return: largest element or NULL if tree empty.
*/
rbnode_type *rbtree_last(rbtree_type *rbtree);
/**
* Returns next larger node in the tree
* @param rbtree: tree
* @return: next larger element or NULL if no larger in tree.
*/
rbnode_type *rbtree_next(rbnode_type *rbtree);
/**
* Returns previous smaller node in the tree
* @param rbtree: tree
* @return: previous smaller element or NULL if no previous in tree.
*/
rbnode_type *rbtree_previous(rbnode_type *rbtree);
/**
* Call with node=variable of struct* with rbnode_type 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_type*)node != RBTREE_NULL; \
node = (type)rbtree_next((rbnode_type*)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_type* tree, void (*func)(rbnode_type*, void*),
void* arg);
#endif /* UTIL_RBTREE_H_ */
