1/*
2 * Copyright (C) 2010 Joseph Adams <joeyadams3.14159@gmail.com>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 * copies of the Software, and to permit persons to whom the Software is
9 * furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20 * THE SOFTWARE.
21 */
22
23#ifndef CCAN_AVL_H
24#define CCAN_AVL_H
25
26#include <stdbool.h>
27#include <stddef.h>
28
29struct sm_state;
30
31typedef struct AvlNode       AvlNode;
32typedef struct AvlIter       AvlIter;
33
34struct stree {
35	AvlNode    *root;
36	struct stree *base_stree;
37	char *has_states;
38	size_t      count;
39	int stree_id;
40	int references;
41};
42
43void free_stree(struct stree **avl);
44	/* Free an stree tree. */
45
46struct sm_state *avl_lookup(const struct stree *avl, const struct sm_state *sm);
47	/* O(log n). Lookup a sm.  Return NULL if the sm is not present. */
48
49#define avl_member(avl, sm) (!!avl_lookup_node(avl, sm))
50	/* O(log n). See if a sm is present. */
51
52size_t stree_count(const struct stree *avl);
53	/* O(1). Return the number of elements in the tree. */
54
55bool avl_insert(struct stree **avl, const struct sm_state *sm);
56	/*
57	 * O(log n). Insert an sm or replace it if already present.
58	 *
59	 * Return false if the insertion replaced an existing sm.
60	 */
61
62bool avl_remove(struct stree **avl, const struct sm_state *sm);
63	/*
64	 * O(log n). Remove an sm (if present).
65	 *
66	 * Return true if it was removed.
67	 */
68
69bool avl_check_invariants(struct stree *avl);
70	/* For testing purposes.  This function will always return true :-) */
71
72
73/************************* Traversal *************************/
74
75#define avl_foreach(iter, avl)         avl_traverse(iter, avl, FORWARD)
76	/*
77	 * O(n). Traverse an stree tree in order.
78	 *
79	 * Example:
80	 *
81	 * AvlIter i;
82	 *
83	 * avl_foreach(i, avl)
84	 *     printf("%s -> %s\n", i.sm->name, i.sm->state->name);
85	 */
86
87#define FOR_EACH_SM(avl, _sm) {			\
88	AvlIter _i;				\
89	avl_foreach(_i, avl) {			\
90		_sm = _i.sm;
91
92#define END_FOR_EACH_SM(_sm) }}
93
94#define FOR_EACH_MY_SM(_owner, avl, _sm) {	\
95	AvlIter _i;				\
96	avl_foreach(_i, avl) {			\
97		_sm = _i.sm;			\
98		if (_sm->owner != _owner)	\
99			continue;		\
100
101#define avl_foreach_reverse(iter, avl) avl_traverse(iter, avl, BACKWARD)
102	/* O(n). Traverse an stree tree in reverse order. */
103
104typedef enum AvlDirection {FORWARD = 0, BACKWARD = 1} AvlDirection;
105
106struct AvlIter {
107	struct sm_state *sm;
108	AvlNode      *node;
109
110	/* private */
111	AvlNode      *stack[100];
112	int           stack_index;
113	AvlDirection  direction;
114};
115
116void avl_iter_begin(AvlIter *iter, struct stree *avl, AvlDirection dir);
117void avl_iter_next(AvlIter *iter);
118#define avl_traverse(iter, avl, direction)        \
119	for (avl_iter_begin(&(iter), avl, direction); \
120	     (iter).node != NULL;                     \
121	     avl_iter_next(&iter))
122
123
124/***************** Internal data structures ******************/
125
126struct AvlNode {
127	const struct sm_state *sm;
128
129	AvlNode    *lr[2];
130	int         balance; /* -1, 0, or 1 */
131};
132
133AvlNode *avl_lookup_node(const struct stree *avl, const struct sm_state *sm);
134	/* O(log n). Lookup an stree node by sm.  Return NULL if not present. */
135
136struct stree *clone_stree(struct stree *orig);
137
138void set_stree_id(struct stree **stree, int id);
139int get_stree_id(struct stree *stree);
140
141#endif
142