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/*
* Copyright (C) 2010 Joseph Adams <joeyadams3.14159@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef CCAN_AVL_H
#define CCAN_AVL_H
#include <stdbool.h>
#include <stddef.h>
#include <ccan/order/order.h>
typedef struct AVL AVL;
typedef struct AvlNode AvlNode;
typedef struct AvlIter AvlIter;
AVL *avl_new(total_order_noctx_cb compare);
/* Create a new AVL tree sorted with the given comparison function. */
void avl_free(AVL *avl);
/* Free an AVL tree. */
void *avl_lookup(const AVL *avl, const void *key);
/* O(log n). Lookup a value at a key. Return NULL if the key is not present. */
#define avl_member(avl, key) (!!avl_lookup_node(avl, key))
/* O(log n). See if a key is present. */
size_t avl_count(const AVL *avl);
/* O(1). Return the number of elements in the tree. */
bool avl_insert(AVL *avl, const void *key, const void *value);
/*
* O(log n). Insert a key/value pair, or replace it if already present.
*
* Return false if the insertion replaced an existing key/value.
*/
bool avl_remove(AVL *avl, const void *key);
/*
* O(log n). Remove a key/value pair (if present).
*
* Return true if it was removed.
*/
bool avl_check_invariants(AVL *avl);
/* For testing purposes. This function will always return true :-) */
/************************* Traversal *************************/
#define avl_foreach(iter, avl) avl_traverse(iter, avl, FORWARD)
/*
* O(n). Traverse an AVL tree in order.
*
* Example:
*
* AvlIter i;
*
* avl_foreach(i, avl)
* printf("%s -> %s\n", i.key, i.value);
*/
#define avl_foreach_reverse(iter, avl) avl_traverse(iter, avl, BACKWARD)
/* O(n). Traverse an AVL tree in reverse order. */
typedef enum AvlDirection {FORWARD = 0, BACKWARD = 1} AvlDirection;
struct AvlIter {
void *key;
void *value;
AvlNode *node;
/* private */
AvlNode *stack[100];
int stack_index;
AvlDirection direction;
};
void avl_iter_begin(AvlIter *iter, AVL *avl, AvlDirection dir);
void avl_iter_next(AvlIter *iter);
#define avl_traverse(iter, avl, direction) \
for (avl_iter_begin(&(iter), avl, direction); \
(iter).node != NULL; \
avl_iter_next(&iter))
/***************** Internal data structures ******************/
struct AVL {
total_order_noctx_cb compare;
AvlNode *root;
size_t count;
};
struct AvlNode {
const void *key;
const void *value;
AvlNode *lr[2];
int balance; /* -1, 0, or 1 */
};
AvlNode *avl_lookup_node(const AVL *avl, const void *key);
/* O(log n). Lookup an AVL node by key. Return NULL if not present. */
#endif
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