1/////////////////////////////////////////////////////////////////////////////
2//
3// (C) Copyright Daniel K. O. 2005.
4// (C) Copyright Ion Gaztanaga 2007-2014
5//
6// Distributed under the Boost Software License, Version 1.0.
7// (See accompanying file LICENSE_1_0.txt or copy at
8// http://www.boost.org/LICENSE_1_0.txt)
9//
10// See http://www.boost.org/libs/intrusive for documentation.
11//
12/////////////////////////////////////////////////////////////////////////////
13
14#ifndef BOOST_INTRUSIVE_AVLTREE_ALGORITHMS_HPP
15#define BOOST_INTRUSIVE_AVLTREE_ALGORITHMS_HPP
16
17#include <boost/intrusive/detail/config_begin.hpp>
18#include <boost/intrusive/intrusive_fwd.hpp>
19
20#include <cstddef>
21
22#include <boost/intrusive/detail/assert.hpp>
23#include <boost/intrusive/detail/algo_type.hpp>
24#include <boost/intrusive/detail/ebo_functor_holder.hpp>
25#include <boost/intrusive/bstree_algorithms.hpp>
26
27#if defined(BOOST_HAS_PRAGMA_ONCE)
28# pragma once
29#endif
30
31
32namespace boost {
33namespace intrusive {
34
35/// @cond
36
37template<class NodeTraits, class F>
38struct avltree_node_cloner
39 //Use public inheritance to avoid MSVC bugs with closures
40 : public detail::ebo_functor_holder<F>
41{
42 typedef typename NodeTraits::node_ptr node_ptr;
43 typedef detail::ebo_functor_holder<F> base_t;
44
45 avltree_node_cloner(F f)
46 : base_t(f)
47 {}
48
49 node_ptr operator()(const node_ptr & p)
50 {
51 node_ptr n = base_t::get()(p);
52 NodeTraits::set_balance(n, NodeTraits::get_balance(p));
53 return n;
54 }
55
56 node_ptr operator()(const node_ptr & p) const
57 {
58 node_ptr n = base_t::get()(p);
59 NodeTraits::set_balance(n, NodeTraits::get_balance(p));
60 return n;
61 }
62};
63
64namespace detail {
65
66template<class ValueTraits, class NodePtrCompare, class ExtraChecker>
67struct avltree_node_checker
68 : public bstree_node_checker<ValueTraits, NodePtrCompare, ExtraChecker>
69{
70 typedef bstree_node_checker<ValueTraits, NodePtrCompare, ExtraChecker> base_checker_t;
71 typedef ValueTraits value_traits;
72 typedef typename value_traits::node_traits node_traits;
73 typedef typename node_traits::const_node_ptr const_node_ptr;
74
75 struct return_type
76 : public base_checker_t::return_type
77 {
78 return_type() : height(0) {}
79 int height;
80 };
81
82 avltree_node_checker(const NodePtrCompare& comp, ExtraChecker extra_checker)
83 : base_checker_t(comp, extra_checker)
84 {}
85
86 void operator () (const const_node_ptr& p,
87 const return_type& check_return_left, const return_type& check_return_right,
88 return_type& check_return)
89 {
90 const int height_diff = check_return_right.height - check_return_left.height; (void)height_diff;
91 BOOST_INTRUSIVE_INVARIANT_ASSERT(
92 (height_diff == -1 && node_traits::get_balance(p) == node_traits::negative()) ||
93 (height_diff == 0 && node_traits::get_balance(p) == node_traits::zero()) ||
94 (height_diff == 1 && node_traits::get_balance(p) == node_traits::positive())
95 );
96 check_return.height = 1 +
97 (check_return_left.height > check_return_right.height ? check_return_left.height : check_return_right.height);
98 base_checker_t::operator()(p, check_return_left, check_return_right, check_return);
99 }
100};
101
102} // namespace detail
103
104/// @endcond
105
106//! avltree_algorithms is configured with a NodeTraits class, which encapsulates the
107//! information about the node to be manipulated. NodeTraits must support the
108//! following interface:
109//!
110//! <b>Typedefs</b>:
111//!
112//! <tt>node</tt>: The type of the node that forms the binary search tree
113//!
114//! <tt>node_ptr</tt>: A pointer to a node
115//!
116//! <tt>const_node_ptr</tt>: A pointer to a const node
117//!
118//! <tt>balance</tt>: The type of the balance factor
119//!
120//! <b>Static functions</b>:
121//!
122//! <tt>static node_ptr get_parent(const_node_ptr n);</tt>
123//!
124//! <tt>static void set_parent(node_ptr n, node_ptr parent);</tt>
125//!
126//! <tt>static node_ptr get_left(const_node_ptr n);</tt>
127//!
128//! <tt>static void set_left(node_ptr n, node_ptr left);</tt>
129//!
130//! <tt>static node_ptr get_right(const_node_ptr n);</tt>
131//!
132//! <tt>static void set_right(node_ptr n, node_ptr right);</tt>
133//!
134//! <tt>static balance get_balance(const_node_ptr n);</tt>
135//!
136//! <tt>static void set_balance(node_ptr n, balance b);</tt>
137//!
138//! <tt>static balance negative();</tt>
139//!
140//! <tt>static balance zero();</tt>
141//!
142//! <tt>static balance positive();</tt>
143template<class NodeTraits>
144class avltree_algorithms
145 #ifndef BOOST_INTRUSIVE_DOXYGEN_INVOKED
146 : public bstree_algorithms<NodeTraits>
147 #endif
148{
149 public:
150 typedef typename NodeTraits::node node;
151 typedef NodeTraits node_traits;
152 typedef typename NodeTraits::node_ptr node_ptr;
153 typedef typename NodeTraits::const_node_ptr const_node_ptr;
154 typedef typename NodeTraits::balance balance;
155
156 /// @cond
157 private:
158 typedef bstree_algorithms<NodeTraits> bstree_algo;
159
160 /// @endcond
161
162 public:
163 //! This type is the information that will be
164 //! filled by insert_unique_check
165 typedef typename bstree_algo::insert_commit_data insert_commit_data;
166
167 #ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
168
169 //! @copydoc ::boost::intrusive::bstree_algorithms::get_header(const const_node_ptr&)
170 static node_ptr get_header(const const_node_ptr & n);
171
172 //! @copydoc ::boost::intrusive::bstree_algorithms::begin_node
173 static node_ptr begin_node(const const_node_ptr & header);
174
175 //! @copydoc ::boost::intrusive::bstree_algorithms::end_node
176 static node_ptr end_node(const const_node_ptr & header);
177
178 //! @copydoc ::boost::intrusive::bstree_algorithms::swap_tree
179 static void swap_tree(const node_ptr & header1, const node_ptr & header2);
180
181 #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
182
183 //! @copydoc ::boost::intrusive::bstree_algorithms::swap_nodes(const node_ptr&,const node_ptr&)
184 static void swap_nodes(const node_ptr & node1, const node_ptr & node2)
185 {
186 if(node1 == node2)
187 return;
188
189 node_ptr header1(bstree_algo::get_header(node1)), header2(bstree_algo::get_header(node2));
190 swap_nodes(node1, header1, node2, header2);
191 }
192
193 //! @copydoc ::boost::intrusive::bstree_algorithms::swap_nodes(const node_ptr&,const node_ptr&,const node_ptr&,const node_ptr&)
194 static void swap_nodes(const node_ptr & node1, const node_ptr & header1, const node_ptr & node2, const node_ptr & header2)
195 {
196 if(node1 == node2) return;
197
198 bstree_algo::swap_nodes(node1, header1, node2, header2);
199 //Swap balance
200 balance c = NodeTraits::get_balance(node1);
201 NodeTraits::set_balance(node1, NodeTraits::get_balance(node2));
202 NodeTraits::set_balance(node2, c);
203 }
204
205 //! @copydoc ::boost::intrusive::bstree_algorithms::replace_node(const node_ptr&,const node_ptr&)
206 static void replace_node(const node_ptr & node_to_be_replaced, const node_ptr & new_node)
207 {
208 if(node_to_be_replaced == new_node)
209 return;
210 replace_node(node_to_be_replaced, bstree_algo::get_header(node_to_be_replaced), new_node);
211 }
212
213 //! @copydoc ::boost::intrusive::bstree_algorithms::replace_node(const node_ptr&,const node_ptr&,const node_ptr&)
214 static void replace_node(const node_ptr & node_to_be_replaced, const node_ptr & header, const node_ptr & new_node)
215 {
216 bstree_algo::replace_node(node_to_be_replaced, header, new_node);
217 NodeTraits::set_balance(new_node, NodeTraits::get_balance(node_to_be_replaced));
218 }
219
220 //! @copydoc ::boost::intrusive::bstree_algorithms::unlink(const node_ptr&)
221 static void unlink(const node_ptr & node)
222 {
223 node_ptr x = NodeTraits::get_parent(node);
224 if(x){
225 while(!is_header(p: x))
226 x = NodeTraits::get_parent(x);
227 erase(header: x, z: node);
228 }
229 }
230
231 #ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
232 //! @copydoc ::boost::intrusive::bstree_algorithms::unlink_leftmost_without_rebalance
233 static node_ptr unlink_leftmost_without_rebalance(const node_ptr & header);
234
235 //! @copydoc ::boost::intrusive::bstree_algorithms::unique(const const_node_ptr&)
236 static bool unique(const const_node_ptr & node);
237
238 //! @copydoc ::boost::intrusive::bstree_algorithms::size(const const_node_ptr&)
239 static std::size_t size(const const_node_ptr & header);
240
241 //! @copydoc ::boost::intrusive::bstree_algorithms::next_node(const node_ptr&)
242 static node_ptr next_node(const node_ptr & node);
243
244 //! @copydoc ::boost::intrusive::bstree_algorithms::prev_node(const node_ptr&)
245 static node_ptr prev_node(const node_ptr & node);
246
247 //! @copydoc ::boost::intrusive::bstree_algorithms::init(const node_ptr&)
248 static void init(const node_ptr & node);
249 #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
250
251 //! <b>Requires</b>: node must not be part of any tree.
252 //!
253 //! <b>Effects</b>: Initializes the header to represent an empty tree.
254 //! unique(header) == true.
255 //!
256 //! <b>Complexity</b>: Constant.
257 //!
258 //! <b>Throws</b>: Nothing.
259 //!
260 //! <b>Nodes</b>: If node is inserted in a tree, this function corrupts the tree.
261 static void init_header(const node_ptr & header)
262 {
263 bstree_algo::init_header(header);
264 NodeTraits::set_balance(header, NodeTraits::zero());
265 }
266
267 //! @copydoc ::boost::intrusive::bstree_algorithms::erase(const node_ptr&,const node_ptr&)
268 static node_ptr erase(const node_ptr & header, const node_ptr & z)
269 {
270 typename bstree_algo::data_for_rebalance info;
271 bstree_algo::erase(header, z, info);
272 if(info.y != z){
273 NodeTraits::set_balance(info.y, NodeTraits::get_balance(z));
274 }
275 //Rebalance avltree
276 rebalance_after_erasure(header, x: info.x, x_parent: info.x_parent);
277 return z;
278 }
279
280 //! @copydoc ::boost::intrusive::bstree_algorithms::clone(const const_node_ptr&,const node_ptr&,Cloner,Disposer)
281 template <class Cloner, class Disposer>
282 static void clone
283 (const const_node_ptr & source_header, const node_ptr & target_header, Cloner cloner, Disposer disposer)
284 {
285 avltree_node_cloner<NodeTraits, Cloner> new_cloner(cloner);
286 bstree_algo::clone(source_header, target_header, new_cloner, disposer);
287 }
288
289 #ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
290 //! @copydoc ::boost::intrusive::bstree_algorithms::clear_and_dispose(const node_ptr&,Disposer)
291 template<class Disposer>
292 static void clear_and_dispose(const node_ptr & header, Disposer disposer);
293
294 //! @copydoc ::boost::intrusive::bstree_algorithms::lower_bound(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
295 template<class KeyType, class KeyNodePtrCompare>
296 static node_ptr lower_bound
297 (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp);
298
299 //! @copydoc ::boost::intrusive::bstree_algorithms::upper_bound(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
300 template<class KeyType, class KeyNodePtrCompare>
301 static node_ptr upper_bound
302 (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp);
303
304 //! @copydoc ::boost::intrusive::bstree_algorithms::find(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
305 template<class KeyType, class KeyNodePtrCompare>
306 static node_ptr find
307 (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp);
308
309 //! @copydoc ::boost::intrusive::bstree_algorithms::equal_range(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
310 template<class KeyType, class KeyNodePtrCompare>
311 static std::pair<node_ptr, node_ptr> equal_range
312 (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp);
313
314 //! @copydoc ::boost::intrusive::bstree_algorithms::bounded_range(const const_node_ptr&,const KeyType&,const KeyType&,KeyNodePtrCompare,bool,bool)
315 template<class KeyType, class KeyNodePtrCompare>
316 static std::pair<node_ptr, node_ptr> bounded_range
317 (const const_node_ptr & header, const KeyType &lower_key, const KeyType &upper_key, KeyNodePtrCompare comp
318 , bool left_closed, bool right_closed);
319
320 //! @copydoc ::boost::intrusive::bstree_algorithms::count(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
321 template<class KeyType, class KeyNodePtrCompare>
322 static std::size_t count(const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp);
323
324 #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
325
326 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal_upper_bound(const node_ptr&,const node_ptr&,NodePtrCompare)
327 template<class NodePtrCompare>
328 static node_ptr insert_equal_upper_bound
329 (const node_ptr & h, const node_ptr & new_node, NodePtrCompare comp)
330 {
331 bstree_algo::insert_equal_upper_bound(h, new_node, comp);
332 rebalance_after_insertion(header: h, x: new_node);
333 return new_node;
334 }
335
336 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal_lower_bound(const node_ptr&,const node_ptr&,NodePtrCompare)
337 template<class NodePtrCompare>
338 static node_ptr insert_equal_lower_bound
339 (const node_ptr & h, const node_ptr & new_node, NodePtrCompare comp)
340 {
341 bstree_algo::insert_equal_lower_bound(h, new_node, comp);
342 rebalance_after_insertion(header: h, x: new_node);
343 return new_node;
344 }
345
346 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal(const node_ptr&,const node_ptr&,const node_ptr&,NodePtrCompare)
347 template<class NodePtrCompare>
348 static node_ptr insert_equal
349 (const node_ptr & header, const node_ptr & hint, const node_ptr & new_node, NodePtrCompare comp)
350 {
351 bstree_algo::insert_equal(header, hint, new_node, comp);
352 rebalance_after_insertion(header, x: new_node);
353 return new_node;
354 }
355
356 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_before(const node_ptr&,const node_ptr&,const node_ptr&)
357 static node_ptr insert_before
358 (const node_ptr & header, const node_ptr & pos, const node_ptr & new_node)
359 {
360 bstree_algo::insert_before(header, pos, new_node);
361 rebalance_after_insertion(header, x: new_node);
362 return new_node;
363 }
364
365 //! @copydoc ::boost::intrusive::bstree_algorithms::push_back(const node_ptr&,const node_ptr&)
366 static void push_back(const node_ptr & header, const node_ptr & new_node)
367 {
368 bstree_algo::push_back(header, new_node);
369 rebalance_after_insertion(header, x: new_node);
370 }
371
372 //! @copydoc ::boost::intrusive::bstree_algorithms::push_front(const node_ptr&,const node_ptr&)
373 static void push_front(const node_ptr & header, const node_ptr & new_node)
374 {
375 bstree_algo::push_front(header, new_node);
376 rebalance_after_insertion(header, x: new_node);
377 }
378
379 #ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
380 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_check(const const_node_ptr&,const KeyType&,KeyNodePtrCompare,insert_commit_data&)
381 template<class KeyType, class KeyNodePtrCompare>
382 static std::pair<node_ptr, bool> insert_unique_check
383 (const const_node_ptr & header, const KeyType &key
384 ,KeyNodePtrCompare comp, insert_commit_data &commit_data);
385
386 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_check(const const_node_ptr&,const node_ptr&,const KeyType&,KeyNodePtrCompare,insert_commit_data&)
387 template<class KeyType, class KeyNodePtrCompare>
388 static std::pair<node_ptr, bool> insert_unique_check
389 (const const_node_ptr & header, const node_ptr &hint, const KeyType &key
390 ,KeyNodePtrCompare comp, insert_commit_data &commit_data);
391 #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
392
393 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_commit(const node_ptr&,const node_ptr&,const insert_commit_data &)
394 static void insert_unique_commit
395 (const node_ptr & header, const node_ptr & new_value, const insert_commit_data &commit_data)
396 {
397 bstree_algo::insert_unique_commit(header, new_value, commit_data);
398 rebalance_after_insertion(header, x: new_value);
399 }
400
401 //! @copydoc ::boost::intrusive::bstree_algorithms::is_header
402 static bool is_header(const const_node_ptr & p)
403 { return NodeTraits::get_balance(p) == NodeTraits::zero() && bstree_algo::is_header(p); }
404
405
406 /// @cond
407 static bool verify(const node_ptr &header)
408 {
409 std::size_t height;
410 std::size_t count;
411 return verify_recursion(n: NodeTraits::get_parent(header), count, height);
412 }
413
414 private:
415
416 static bool verify_recursion(node_ptr n, std::size_t &count, std::size_t &height)
417 {
418 if (!n){
419 count = 0;
420 height = 0;
421 return true;
422 }
423 std::size_t leftcount, rightcount;
424 std::size_t leftheight, rightheight;
425 if(!verify_recursion(n: NodeTraits::get_left (n), count&: leftcount, height&: leftheight) ||
426 !verify_recursion(n: NodeTraits::get_right(n), count&: rightcount, height&: rightheight) ){
427 return false;
428 }
429 count = 1u + leftcount + rightcount;
430 height = 1u + (leftheight > rightheight ? leftheight : rightheight);
431
432 //If equal height, balance must be zero
433 if(rightheight == leftheight){
434 if(NodeTraits::get_balance(n) != NodeTraits::zero()){
435 BOOST_ASSERT(0);
436 return false;
437 }
438 }
439 //If right is taller than left, then the difference must be at least 1 and the balance positive
440 else if(rightheight > leftheight){
441 if(rightheight - leftheight > 1 ){
442 BOOST_ASSERT(0);
443 return false;
444 }
445 else if(NodeTraits::get_balance(n) != NodeTraits::positive()){
446 BOOST_ASSERT(0);
447 return false;
448 }
449 }
450 //If left is taller than right, then the difference must be at least 1 and the balance negative
451 else{
452 if(leftheight - rightheight > 1 ){
453 BOOST_ASSERT(0);
454 return false;
455 }
456 else if(NodeTraits::get_balance(n) != NodeTraits::negative()){
457 BOOST_ASSERT(0);
458 return false;
459 }
460 }
461 return true;
462 }
463
464 static void rebalance_after_erasure(const node_ptr & header, node_ptr x, node_ptr x_parent)
465 {
466 for ( node_ptr root = NodeTraits::get_parent(header)
467 ; x != root
468 ; root = NodeTraits::get_parent(header), x_parent = NodeTraits::get_parent(x)) {
469 const balance x_parent_balance = NodeTraits::get_balance(x_parent);
470 //Don't cache x_is_leftchild or similar because x can be null and
471 //equal to both x_parent_left and x_parent_right
472 const node_ptr x_parent_left (NodeTraits::get_left(x_parent));
473 const node_ptr x_parent_right(NodeTraits::get_right(x_parent));
474
475 if(x_parent_balance == NodeTraits::zero()){
476 NodeTraits::set_balance( x_parent, x == x_parent_right ? NodeTraits::negative() : NodeTraits::positive() );
477 break; // the height didn't change, let's stop here
478 }
479 else if(x_parent_balance == NodeTraits::negative()){
480 if (x == x_parent_left) { ////x is left child or x and sibling are null
481 NodeTraits::set_balance(x_parent, NodeTraits::zero()); // balanced
482 x = x_parent;
483 }
484 else {
485 // x is right child (x_parent_left is the left child)
486 BOOST_INTRUSIVE_INVARIANT_ASSERT(x_parent_left);
487 if (NodeTraits::get_balance(x_parent_left) == NodeTraits::positive()) {
488 // x_parent_left MUST have a right child
489 BOOST_INTRUSIVE_INVARIANT_ASSERT(NodeTraits::get_right(x_parent_left));
490 x = avl_rotate_left_right(a: x_parent, a_oldleft: x_parent_left, hdr: header);
491 }
492 else {
493 avl_rotate_right(x: x_parent, x_oldleft: x_parent_left, hdr: header);
494 x = x_parent_left;
495 }
496
497 // if changed from negative to NodeTraits::positive(), no need to check above
498 if (NodeTraits::get_balance(x) == NodeTraits::positive()){
499 break;
500 }
501 }
502 }
503 else if(x_parent_balance == NodeTraits::positive()){
504 if (x == x_parent_right) { //x is right child or x and sibling are null
505 NodeTraits::set_balance(x_parent, NodeTraits::zero()); // balanced
506 x = x_parent;
507 }
508 else {
509 // x is left child (x_parent_right is the right child)
510 BOOST_INTRUSIVE_INVARIANT_ASSERT(x_parent_right);
511 if (NodeTraits::get_balance(x_parent_right) == NodeTraits::negative()) {
512 // x_parent_right MUST have then a left child
513 BOOST_INTRUSIVE_INVARIANT_ASSERT(NodeTraits::get_left(x_parent_right));
514 x = avl_rotate_right_left(a: x_parent, a_oldright: x_parent_right, hdr: header);
515 }
516 else {
517 avl_rotate_left(x: x_parent, x_oldright: x_parent_right, hdr: header);
518 x = x_parent_right;
519 }
520 // if changed from NodeTraits::positive() to negative, no need to check above
521 if (NodeTraits::get_balance(x) == NodeTraits::negative()){
522 break;
523 }
524 }
525 }
526 else{
527 BOOST_INTRUSIVE_INVARIANT_ASSERT(false); // never reached
528 }
529 }
530 }
531
532 static void rebalance_after_insertion(const node_ptr & header, node_ptr x)
533 {
534 NodeTraits::set_balance(x, NodeTraits::zero());
535 // Rebalance.
536 for(node_ptr root = NodeTraits::get_parent(header); x != root; root = NodeTraits::get_parent(header)){
537 node_ptr const x_parent(NodeTraits::get_parent(x));
538 node_ptr const x_parent_left(NodeTraits::get_left(x_parent));
539 const balance x_parent_balance = NodeTraits::get_balance(x_parent);
540 const bool x_is_leftchild(x == x_parent_left);
541 if(x_parent_balance == NodeTraits::zero()){
542 // if x is left, parent will have parent->bal_factor = negative
543 // else, parent->bal_factor = NodeTraits::positive()
544 NodeTraits::set_balance( x_parent, x_is_leftchild ? NodeTraits::negative() : NodeTraits::positive() );
545 x = x_parent;
546 }
547 else if(x_parent_balance == NodeTraits::positive()){
548 // if x is a left child, parent->bal_factor = zero
549 if (x_is_leftchild)
550 NodeTraits::set_balance(x_parent, NodeTraits::zero());
551 else{ // x is a right child, needs rebalancing
552 if (NodeTraits::get_balance(x) == NodeTraits::negative())
553 avl_rotate_right_left(a: x_parent, a_oldright: x, hdr: header);
554 else
555 avl_rotate_left(x: x_parent, x_oldright: x, hdr: header);
556 }
557 break;
558 }
559 else if(x_parent_balance == NodeTraits::negative()){
560 // if x is a left child, needs rebalancing
561 if (x_is_leftchild) {
562 if (NodeTraits::get_balance(x) == NodeTraits::positive())
563 avl_rotate_left_right(a: x_parent, a_oldleft: x, hdr: header);
564 else
565 avl_rotate_right(x: x_parent, x_oldleft: x, hdr: header);
566 }
567 else
568 NodeTraits::set_balance(x_parent, NodeTraits::zero());
569 break;
570 }
571 else{
572 BOOST_INTRUSIVE_INVARIANT_ASSERT(false); // never reached
573 }
574 }
575 }
576
577 static void left_right_balancing(const node_ptr & a, const node_ptr & b, const node_ptr & c)
578 {
579 // balancing...
580 const balance c_balance = NodeTraits::get_balance(c);
581 const balance zero_balance = NodeTraits::zero();
582 const balance posi_balance = NodeTraits::positive();
583 const balance nega_balance = NodeTraits::negative();
584 NodeTraits::set_balance(c, zero_balance);
585 if(c_balance == nega_balance){
586 NodeTraits::set_balance(a, posi_balance);
587 NodeTraits::set_balance(b, zero_balance);
588 }
589 else if(c_balance == zero_balance){
590 NodeTraits::set_balance(a, zero_balance);
591 NodeTraits::set_balance(b, zero_balance);
592 }
593 else if(c_balance == posi_balance){
594 NodeTraits::set_balance(a, zero_balance);
595 NodeTraits::set_balance(b, nega_balance);
596 }
597 else{
598 BOOST_INTRUSIVE_INVARIANT_ASSERT(false); // never reached
599 }
600 }
601
602 static node_ptr avl_rotate_left_right(const node_ptr a, const node_ptr a_oldleft, const node_ptr & hdr)
603 { // [note: 'a_oldleft' is 'b']
604 // | | //
605 // a(-2) c //
606 // / \ / \ //
607 // / \ ==> / \ //
608 // (pos)b [g] b a //
609 // / \ / \ / \ //
610 // [d] c [d] e f [g] //
611 // / \ //
612 // e f //
613 const node_ptr c = NodeTraits::get_right(a_oldleft);
614 bstree_algo::rotate_left_no_parent_fix(a_oldleft, c);
615 //No need to link c with a [NodeTraits::set_parent(c, a) + NodeTraits::set_left(a, c)]
616 //as c is not root and another rotation is coming
617 bstree_algo::rotate_right(a, c, NodeTraits::get_parent(a), hdr);
618 left_right_balancing(a, b: a_oldleft, c);
619 return c;
620 }
621
622 static node_ptr avl_rotate_right_left(const node_ptr a, const node_ptr a_oldright, const node_ptr & hdr)
623 { // [note: 'a_oldright' is 'b']
624 // | | //
625 // a(pos) c //
626 // / \ / \ //
627 // / \ / \ //
628 // [d] b(neg) ==> a b //
629 // / \ / \ / \ //
630 // c [g] [d] e f [g] //
631 // / \ //
632 // e f //
633 const node_ptr c (NodeTraits::get_left(a_oldright));
634 bstree_algo::rotate_right_no_parent_fix(a_oldright, c);
635 //No need to link c with a [NodeTraits::set_parent(c, a) + NodeTraits::set_right(a, c)]
636 //as c is not root and another rotation is coming.
637 bstree_algo::rotate_left(a, c, NodeTraits::get_parent(a), hdr);
638 left_right_balancing(a: a_oldright, b: a, c);
639 return c;
640 }
641
642 static void avl_rotate_left(const node_ptr &x, const node_ptr &x_oldright, const node_ptr & hdr)
643 {
644 bstree_algo::rotate_left(x, x_oldright, NodeTraits::get_parent(x), hdr);
645
646 // reset the balancing factor
647 if (NodeTraits::get_balance(x_oldright) == NodeTraits::positive()) {
648 NodeTraits::set_balance(x, NodeTraits::zero());
649 NodeTraits::set_balance(x_oldright, NodeTraits::zero());
650 }
651 else { // this doesn't happen during insertions
652 NodeTraits::set_balance(x, NodeTraits::positive());
653 NodeTraits::set_balance(x_oldright, NodeTraits::negative());
654 }
655 }
656
657 static void avl_rotate_right(const node_ptr &x, const node_ptr &x_oldleft, const node_ptr & hdr)
658 {
659 bstree_algo::rotate_right(x, x_oldleft, NodeTraits::get_parent(x), hdr);
660
661 // reset the balancing factor
662 if (NodeTraits::get_balance(x_oldleft) == NodeTraits::negative()) {
663 NodeTraits::set_balance(x, NodeTraits::zero());
664 NodeTraits::set_balance(x_oldleft, NodeTraits::zero());
665 }
666 else { // this doesn't happen during insertions
667 NodeTraits::set_balance(x, NodeTraits::negative());
668 NodeTraits::set_balance(x_oldleft, NodeTraits::positive());
669 }
670 }
671
672 /// @endcond
673};
674
675/// @cond
676
677template<class NodeTraits>
678struct get_algo<AvlTreeAlgorithms, NodeTraits>
679{
680 typedef avltree_algorithms<NodeTraits> type;
681};
682
683template <class ValueTraits, class NodePtrCompare, class ExtraChecker>
684struct get_node_checker<AvlTreeAlgorithms, ValueTraits, NodePtrCompare, ExtraChecker>
685{
686 typedef detail::avltree_node_checker<ValueTraits, NodePtrCompare, ExtraChecker> type;
687};
688
689/// @endcond
690
691} //namespace intrusive
692} //namespace boost
693
694#include <boost/intrusive/detail/config_end.hpp>
695
696#endif //BOOST_INTRUSIVE_AVLTREE_ALGORITHMS_HPP
697

source code of boost/boost/intrusive/avltree_algorithms.hpp