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 inline avltree_node_cloner(F f)
46 : base_t(f)
47 {}
48
49 node_ptr operator()(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()(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_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_node_ptr)
170 static node_ptr get_header(const_node_ptr n) BOOST_NOEXCEPT;
171
172 //! @copydoc ::boost::intrusive::bstree_algorithms::begin_node
173 static node_ptr begin_node(const_node_ptr header) BOOST_NOEXCEPT;
174
175 //! @copydoc ::boost::intrusive::bstree_algorithms::end_node
176 static node_ptr end_node(const_node_ptr header) BOOST_NOEXCEPT;
177
178 //! @copydoc ::boost::intrusive::bstree_algorithms::swap_tree
179 static void swap_tree(node_ptr header1, node_ptr header2) BOOST_NOEXCEPT;
180
181 #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
182
183 //! @copydoc ::boost::intrusive::bstree_algorithms::swap_nodes(node_ptr,node_ptr)
184 static void swap_nodes(node_ptr node1, node_ptr node2) BOOST_NOEXCEPT
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(node_ptr,node_ptr,node_ptr,node_ptr)
194 static void swap_nodes(node_ptr node1, node_ptr header1, node_ptr node2, node_ptr header2) BOOST_NOEXCEPT
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(node_ptr,node_ptr)
206 static void replace_node(node_ptr node_to_be_replaced, node_ptr new_node) BOOST_NOEXCEPT
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(node_ptr,node_ptr,node_ptr)
214 static void replace_node(node_ptr node_to_be_replaced, node_ptr header, node_ptr new_node) BOOST_NOEXCEPT
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(node_ptr)
221 static void unlink(node_ptr n) BOOST_NOEXCEPT
222 {
223 node_ptr x = NodeTraits::get_parent(n);
224 if(x){
225 while(!is_header(p: x))
226 x = NodeTraits::get_parent(x);
227 erase(header: x, z: n);
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(node_ptr header) BOOST_NOEXCEPT;
234
235 //! @copydoc ::boost::intrusive::bstree_algorithms::unique(const_node_ptr)
236 static bool unique(const_node_ptr n) BOOST_NOEXCEPT;
237
238 //! @copydoc ::boost::intrusive::bstree_algorithms::size(const_node_ptr)
239 static std::size_t size(const_node_ptr header) BOOST_NOEXCEPT;
240
241 //! @copydoc ::boost::intrusive::bstree_algorithms::next_node(node_ptr)
242 static node_ptr next_node(node_ptr n) BOOST_NOEXCEPT;
243
244 //! @copydoc ::boost::intrusive::bstree_algorithms::prev_node(node_ptr)
245 static node_ptr prev_node(node_ptr n) BOOST_NOEXCEPT;
246
247 //! @copydoc ::boost::intrusive::bstree_algorithms::init(node_ptr)
248 static void init(node_ptr n) BOOST_NOEXCEPT;
249 #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
250
251 //! <b>Requires</b>: header 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 header is inserted in a tree, this function corrupts the tree.
261 static void init_header(node_ptr header) BOOST_NOEXCEPT
262 {
263 bstree_algo::init_header(header);
264 NodeTraits::set_balance(header, NodeTraits::zero());
265 }
266
267 //! @copydoc ::boost::intrusive::bstree_algorithms::erase(node_ptr,node_ptr)
268 static node_ptr erase(node_ptr header, node_ptr z) BOOST_NOEXCEPT
269 {
270 typename bstree_algo::data_for_rebalance info;
271 bstree_algo::erase(header, z, info);
272 rebalance_after_erasure(header, z, info);
273 return z;
274 }
275
276 //! @copydoc ::boost::intrusive::bstree_algorithms::transfer_unique
277 template<class NodePtrCompare>
278 static bool transfer_unique
279 (node_ptr header1, NodePtrCompare comp, node_ptr header2, node_ptr z)
280 {
281 typename bstree_algo::data_for_rebalance info;
282 bool const transferred = bstree_algo::transfer_unique(header1, comp, header2, z, info);
283 if(transferred){
284 rebalance_after_erasure(header: header2, z, info);
285 rebalance_after_insertion(header: header1, x: z);
286 }
287 return transferred;
288 }
289
290 //! @copydoc ::boost::intrusive::bstree_algorithms::transfer_equal
291 template<class NodePtrCompare>
292 static void transfer_equal
293 (node_ptr header1, NodePtrCompare comp, node_ptr header2, node_ptr z)
294 {
295 typename bstree_algo::data_for_rebalance info;
296 bstree_algo::transfer_equal(header1, comp, header2, z, info);
297 rebalance_after_erasure(header: header2, z, info);
298 rebalance_after_insertion(header: header1, x: z);
299 }
300
301 //! @copydoc ::boost::intrusive::bstree_algorithms::clone(const_node_ptr,node_ptr,Cloner,Disposer)
302 template <class Cloner, class Disposer>
303 static void clone
304 (const_node_ptr source_header, node_ptr target_header, Cloner cloner, Disposer disposer)
305 {
306 avltree_node_cloner<NodeTraits, Cloner> new_cloner(cloner);
307 bstree_algo::clone(source_header, target_header, new_cloner, disposer);
308 }
309
310 #ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
311 //! @copydoc ::boost::intrusive::bstree_algorithms::clear_and_dispose(node_ptr,Disposer)
312 template<class Disposer>
313 static void clear_and_dispose(node_ptr header, Disposer disposer) BOOST_NOEXCEPT;
314
315 //! @copydoc ::boost::intrusive::bstree_algorithms::lower_bound(const_node_ptr,const KeyType&,KeyNodePtrCompare)
316 template<class KeyType, class KeyNodePtrCompare>
317 static node_ptr lower_bound
318 (const_node_ptr header, const KeyType &key, KeyNodePtrCompare comp);
319
320 //! @copydoc ::boost::intrusive::bstree_algorithms::upper_bound(const_node_ptr,const KeyType&,KeyNodePtrCompare)
321 template<class KeyType, class KeyNodePtrCompare>
322 static node_ptr upper_bound
323 (const_node_ptr header, const KeyType &key, KeyNodePtrCompare comp);
324
325 //! @copydoc ::boost::intrusive::bstree_algorithms::find(const_node_ptr,const KeyType&,KeyNodePtrCompare)
326 template<class KeyType, class KeyNodePtrCompare>
327 static node_ptr find
328 (const_node_ptr header, const KeyType &key, KeyNodePtrCompare comp);
329
330 //! @copydoc ::boost::intrusive::bstree_algorithms::equal_range(const_node_ptr,const KeyType&,KeyNodePtrCompare)
331 template<class KeyType, class KeyNodePtrCompare>
332 static std::pair<node_ptr, node_ptr> equal_range
333 (const_node_ptr header, const KeyType &key, KeyNodePtrCompare comp);
334
335 //! @copydoc ::boost::intrusive::bstree_algorithms::bounded_range(const_node_ptr,const KeyType&,const KeyType&,KeyNodePtrCompare,bool,bool)
336 template<class KeyType, class KeyNodePtrCompare>
337 static std::pair<node_ptr, node_ptr> bounded_range
338 (const_node_ptr header, const KeyType &lower_key, const KeyType &upper_key, KeyNodePtrCompare comp
339 , bool left_closed, bool right_closed);
340
341 //! @copydoc ::boost::intrusive::bstree_algorithms::count(const_node_ptr,const KeyType&,KeyNodePtrCompare)
342 template<class KeyType, class KeyNodePtrCompare>
343 static std::size_t count(const_node_ptr header, const KeyType &key, KeyNodePtrCompare comp);
344
345 #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
346
347 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal_upper_bound(node_ptr,node_ptr,NodePtrCompare)
348 template<class NodePtrCompare>
349 static node_ptr insert_equal_upper_bound
350 (node_ptr h, node_ptr new_node, NodePtrCompare comp)
351 {
352 bstree_algo::insert_equal_upper_bound(h, new_node, comp);
353 rebalance_after_insertion(header: h, x: new_node);
354 return new_node;
355 }
356
357 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal_lower_bound(node_ptr,node_ptr,NodePtrCompare)
358 template<class NodePtrCompare>
359 static node_ptr insert_equal_lower_bound
360 (node_ptr h, node_ptr new_node, NodePtrCompare comp)
361 {
362 bstree_algo::insert_equal_lower_bound(h, new_node, comp);
363 rebalance_after_insertion(header: h, x: new_node);
364 return new_node;
365 }
366
367 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal(node_ptr,node_ptr,node_ptr,NodePtrCompare)
368 template<class NodePtrCompare>
369 static node_ptr insert_equal
370 (node_ptr header, node_ptr hint, node_ptr new_node, NodePtrCompare comp)
371 {
372 bstree_algo::insert_equal(header, hint, new_node, comp);
373 rebalance_after_insertion(header, x: new_node);
374 return new_node;
375 }
376
377 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_before(node_ptr,node_ptr,node_ptr)
378 static node_ptr insert_before
379 (node_ptr header, node_ptr pos, node_ptr new_node) BOOST_NOEXCEPT
380 {
381 bstree_algo::insert_before(header, pos, new_node);
382 rebalance_after_insertion(header, x: new_node);
383 return new_node;
384 }
385
386 //! @copydoc ::boost::intrusive::bstree_algorithms::push_back(node_ptr,node_ptr)
387 static void push_back(node_ptr header, node_ptr new_node) BOOST_NOEXCEPT
388 {
389 bstree_algo::push_back(header, new_node);
390 rebalance_after_insertion(header, x: new_node);
391 }
392
393 //! @copydoc ::boost::intrusive::bstree_algorithms::push_front(node_ptr,node_ptr)
394 static void push_front(node_ptr header, node_ptr new_node) BOOST_NOEXCEPT
395 {
396 bstree_algo::push_front(header, new_node);
397 rebalance_after_insertion(header, x: new_node);
398 }
399
400 #ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
401 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_check(const_node_ptr,const KeyType&,KeyNodePtrCompare,insert_commit_data&)
402 template<class KeyType, class KeyNodePtrCompare>
403 static std::pair<node_ptr, bool> insert_unique_check
404 (const_node_ptr header, const KeyType &key
405 ,KeyNodePtrCompare comp, insert_commit_data &commit_data);
406
407 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_check(const_node_ptr,node_ptr,const KeyType&,KeyNodePtrCompare,insert_commit_data&)
408 template<class KeyType, class KeyNodePtrCompare>
409 static std::pair<node_ptr, bool> insert_unique_check
410 (const_node_ptr header, node_ptr hint, const KeyType &key
411 ,KeyNodePtrCompare comp, insert_commit_data &commit_data);
412 #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
413
414 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_commit(node_ptr,node_ptr,const insert_commit_data &)
415 static void insert_unique_commit
416 (node_ptr header, node_ptr new_value, const insert_commit_data &commit_data) BOOST_NOEXCEPT
417 {
418 bstree_algo::insert_unique_commit(header, new_value, commit_data);
419 rebalance_after_insertion(header, x: new_value);
420 }
421
422 //! @copydoc ::boost::intrusive::bstree_algorithms::is_header
423 static bool is_header(const_node_ptr p) BOOST_NOEXCEPT
424 { return NodeTraits::get_balance(p) == NodeTraits::zero() && bstree_algo::is_header(p); }
425
426
427 /// @cond
428 static bool verify(node_ptr header)
429 {
430 std::size_t height;
431 std::size_t count;
432 return verify_recursion(n: NodeTraits::get_parent(header), count, height);
433 }
434
435 private:
436
437 static bool verify_recursion(node_ptr n, std::size_t &count, std::size_t &height)
438 {
439 if (!n){
440 count = 0;
441 height = 0;
442 return true;
443 }
444 std::size_t leftcount, rightcount;
445 std::size_t leftheight, rightheight;
446 if(!verify_recursion(n: NodeTraits::get_left (n), count&: leftcount, height&: leftheight) ||
447 !verify_recursion(n: NodeTraits::get_right(n), count&: rightcount, height&: rightheight) ){
448 return false;
449 }
450 count = 1u + leftcount + rightcount;
451 height = 1u + (leftheight > rightheight ? leftheight : rightheight);
452
453 //If equal height, balance must be zero
454 if(rightheight == leftheight){
455 if(NodeTraits::get_balance(n) != NodeTraits::zero()){
456 BOOST_ASSERT(0);
457 return false;
458 }
459 }
460 //If right is taller than left, then the difference must be at least 1 and the balance positive
461 else if(rightheight > leftheight){
462 if(rightheight - leftheight > 1 ){
463 BOOST_ASSERT(0);
464 return false;
465 }
466 else if(NodeTraits::get_balance(n) != NodeTraits::positive()){
467 BOOST_ASSERT(0);
468 return false;
469 }
470 }
471 //If left is taller than right, then the difference must be at least 1 and the balance negative
472 else{
473 if(leftheight - rightheight > 1 ){
474 BOOST_ASSERT(0);
475 return false;
476 }
477 else if(NodeTraits::get_balance(n) != NodeTraits::negative()){
478 BOOST_ASSERT(0);
479 return false;
480 }
481 }
482 return true;
483 }
484
485 static void rebalance_after_erasure
486 ( node_ptr header, node_ptr z, const typename bstree_algo::data_for_rebalance &info) BOOST_NOEXCEPT
487 {
488 if(info.y != z){
489 NodeTraits::set_balance(info.y, NodeTraits::get_balance(z));
490 }
491 //Rebalance avltree
492 rebalance_after_erasure_restore_invariants(header, x: info.x, x_parent: info.x_parent);
493 }
494
495 static void rebalance_after_erasure_restore_invariants(node_ptr header, node_ptr x, node_ptr x_parent) BOOST_NOEXCEPT
496 {
497 for ( node_ptr root = NodeTraits::get_parent(header)
498 ; x != root
499 ; root = NodeTraits::get_parent(header), x_parent = NodeTraits::get_parent(x)) {
500 const balance x_parent_balance = NodeTraits::get_balance(x_parent);
501 //Don't cache x_is_leftchild or similar because x can be null and
502 //equal to both x_parent_left and x_parent_right
503 const node_ptr x_parent_left (NodeTraits::get_left(x_parent));
504 const node_ptr x_parent_right(NodeTraits::get_right(x_parent));
505
506 if(x_parent_balance == NodeTraits::zero()){
507 NodeTraits::set_balance( x_parent, x == x_parent_right ? NodeTraits::negative() : NodeTraits::positive() );
508 break; // the height didn't change, let's stop here
509 }
510 else if(x_parent_balance == NodeTraits::negative()){
511 if (x == x_parent_left) { ////x is left child or x and sibling are null
512 NodeTraits::set_balance(x_parent, NodeTraits::zero()); // balanced
513 x = x_parent;
514 }
515 else {
516 // x is right child (x_parent_left is the left child)
517 BOOST_INTRUSIVE_INVARIANT_ASSERT(x_parent_left);
518 if (NodeTraits::get_balance(x_parent_left) == NodeTraits::positive()) {
519 // x_parent_left MUST have a right child
520 BOOST_INTRUSIVE_INVARIANT_ASSERT(NodeTraits::get_right(x_parent_left));
521 x = avl_rotate_left_right(a: x_parent, a_oldleft: x_parent_left, hdr: header);
522 }
523 else {
524 avl_rotate_right(x: x_parent, x_oldleft: x_parent_left, hdr: header);
525 x = x_parent_left;
526 }
527
528 // if changed from negative to NodeTraits::positive(), no need to check above
529 if (NodeTraits::get_balance(x) == NodeTraits::positive()){
530 break;
531 }
532 }
533 }
534 else if(x_parent_balance == NodeTraits::positive()){
535 if (x == x_parent_right) { //x is right child or x and sibling are null
536 NodeTraits::set_balance(x_parent, NodeTraits::zero()); // balanced
537 x = x_parent;
538 }
539 else {
540 // x is left child (x_parent_right is the right child)
541 BOOST_INTRUSIVE_INVARIANT_ASSERT(x_parent_right);
542 if (NodeTraits::get_balance(x_parent_right) == NodeTraits::negative()) {
543 // x_parent_right MUST have then a left child
544 BOOST_INTRUSIVE_INVARIANT_ASSERT(NodeTraits::get_left(x_parent_right));
545 x = avl_rotate_right_left(a: x_parent, a_oldright: x_parent_right, hdr: header);
546 }
547 else {
548 avl_rotate_left(x: x_parent, x_oldright: x_parent_right, hdr: header);
549 x = x_parent_right;
550 }
551 // if changed from NodeTraits::positive() to negative, no need to check above
552 if (NodeTraits::get_balance(x) == NodeTraits::negative()){
553 break;
554 }
555 }
556 }
557 else{
558 BOOST_INTRUSIVE_INVARIANT_ASSERT(false); // never reached
559 }
560 }
561 }
562
563 static void rebalance_after_insertion(node_ptr header, node_ptr x) BOOST_NOEXCEPT
564 {
565 NodeTraits::set_balance(x, NodeTraits::zero());
566 // Rebalance.
567 for(node_ptr root = NodeTraits::get_parent(header); x != root; root = NodeTraits::get_parent(header)){
568 node_ptr const x_parent(NodeTraits::get_parent(x));
569 node_ptr const x_parent_left(NodeTraits::get_left(x_parent));
570 const balance x_parent_balance = NodeTraits::get_balance(x_parent);
571 const bool x_is_leftchild(x == x_parent_left);
572 if(x_parent_balance == NodeTraits::zero()){
573 // if x is left, parent will have parent->bal_factor = negative
574 // else, parent->bal_factor = NodeTraits::positive()
575 NodeTraits::set_balance( x_parent, x_is_leftchild ? NodeTraits::negative() : NodeTraits::positive() );
576 x = x_parent;
577 }
578 else if(x_parent_balance == NodeTraits::positive()){
579 // if x is a left child, parent->bal_factor = zero
580 if (x_is_leftchild)
581 NodeTraits::set_balance(x_parent, NodeTraits::zero());
582 else{ // x is a right child, needs rebalancing
583 if (NodeTraits::get_balance(x) == NodeTraits::negative())
584 avl_rotate_right_left(a: x_parent, a_oldright: x, hdr: header);
585 else
586 avl_rotate_left(x: x_parent, x_oldright: x, hdr: header);
587 }
588 break;
589 }
590 else if(x_parent_balance == NodeTraits::negative()){
591 // if x is a left child, needs rebalancing
592 if (x_is_leftchild) {
593 if (NodeTraits::get_balance(x) == NodeTraits::positive())
594 avl_rotate_left_right(a: x_parent, a_oldleft: x, hdr: header);
595 else
596 avl_rotate_right(x: x_parent, x_oldleft: x, hdr: header);
597 }
598 else
599 NodeTraits::set_balance(x_parent, NodeTraits::zero());
600 break;
601 }
602 else{
603 BOOST_INTRUSIVE_INVARIANT_ASSERT(false); // never reached
604 }
605 }
606 }
607
608 static void left_right_balancing(node_ptr a, node_ptr b, node_ptr c) BOOST_NOEXCEPT
609 {
610 // balancing...
611 const balance c_balance = NodeTraits::get_balance(c);
612 const balance zero_balance = NodeTraits::zero();
613 const balance posi_balance = NodeTraits::positive();
614 const balance nega_balance = NodeTraits::negative();
615 NodeTraits::set_balance(c, zero_balance);
616 if(c_balance == nega_balance){
617 NodeTraits::set_balance(a, posi_balance);
618 NodeTraits::set_balance(b, zero_balance);
619 }
620 else if(c_balance == zero_balance){
621 NodeTraits::set_balance(a, zero_balance);
622 NodeTraits::set_balance(b, zero_balance);
623 }
624 else if(c_balance == posi_balance){
625 NodeTraits::set_balance(a, zero_balance);
626 NodeTraits::set_balance(b, nega_balance);
627 }
628 else{
629 BOOST_INTRUSIVE_INVARIANT_ASSERT(false); // never reached
630 }
631 }
632
633 static node_ptr avl_rotate_left_right(const node_ptr a, const node_ptr a_oldleft, node_ptr hdr) BOOST_NOEXCEPT
634 { // [note: 'a_oldleft' is 'b']
635 // | | //
636 // a(-2) c //
637 // / \ / \ //
638 // / \ ==> / \ //
639 // (pos)b [g] b a //
640 // / \ / \ / \ //
641 // [d] c [d] e f [g] //
642 // / \ //
643 // e f //
644 const node_ptr c = NodeTraits::get_right(a_oldleft);
645 bstree_algo::rotate_left_no_parent_fix(a_oldleft, c);
646 //No need to link c with a [NodeTraits::set_parent(c, a) + NodeTraits::set_left(a, c)]
647 //as c is not root and another rotation is coming
648 bstree_algo::rotate_right(a, c, NodeTraits::get_parent(a), hdr);
649 left_right_balancing(a, b: a_oldleft, c);
650 return c;
651 }
652
653 static node_ptr avl_rotate_right_left(const node_ptr a, const node_ptr a_oldright, node_ptr hdr) BOOST_NOEXCEPT
654 { // [note: 'a_oldright' is 'b']
655 // | | //
656 // a(pos) c //
657 // / \ / \ //
658 // / \ / \ //
659 // [d] b(neg) ==> a b //
660 // / \ / \ / \ //
661 // c [g] [d] e f [g] //
662 // / \ //
663 // e f //
664 const node_ptr c (NodeTraits::get_left(a_oldright));
665 bstree_algo::rotate_right_no_parent_fix(a_oldright, c);
666 //No need to link c with a [NodeTraits::set_parent(c, a) + NodeTraits::set_right(a, c)]
667 //as c is not root and another rotation is coming.
668 bstree_algo::rotate_left(a, c, NodeTraits::get_parent(a), hdr);
669 left_right_balancing(a: a_oldright, b: a, c);
670 return c;
671 }
672
673 static void avl_rotate_left(node_ptr x, node_ptr x_oldright, node_ptr hdr) BOOST_NOEXCEPT
674 {
675 bstree_algo::rotate_left(x, x_oldright, NodeTraits::get_parent(x), hdr);
676
677 // reset the balancing factor
678 if (NodeTraits::get_balance(x_oldright) == NodeTraits::positive()) {
679 NodeTraits::set_balance(x, NodeTraits::zero());
680 NodeTraits::set_balance(x_oldright, NodeTraits::zero());
681 }
682 else { // this doesn't happen during insertions
683 NodeTraits::set_balance(x, NodeTraits::positive());
684 NodeTraits::set_balance(x_oldright, NodeTraits::negative());
685 }
686 }
687
688 static void avl_rotate_right(node_ptr x, node_ptr x_oldleft, node_ptr hdr) BOOST_NOEXCEPT
689 {
690 bstree_algo::rotate_right(x, x_oldleft, NodeTraits::get_parent(x), hdr);
691
692 // reset the balancing factor
693 if (NodeTraits::get_balance(x_oldleft) == NodeTraits::negative()) {
694 NodeTraits::set_balance(x, NodeTraits::zero());
695 NodeTraits::set_balance(x_oldleft, NodeTraits::zero());
696 }
697 else { // this doesn't happen during insertions
698 NodeTraits::set_balance(x, NodeTraits::negative());
699 NodeTraits::set_balance(x_oldleft, NodeTraits::positive());
700 }
701 }
702
703 /// @endcond
704};
705
706/// @cond
707
708template<class NodeTraits>
709struct get_algo<AvlTreeAlgorithms, NodeTraits>
710{
711 typedef avltree_algorithms<NodeTraits> type;
712};
713
714template <class ValueTraits, class NodePtrCompare, class ExtraChecker>
715struct get_node_checker<AvlTreeAlgorithms, ValueTraits, NodePtrCompare, ExtraChecker>
716{
717 typedef detail::avltree_node_checker<ValueTraits, NodePtrCompare, ExtraChecker> type;
718};
719
720/// @endcond
721
722} //namespace intrusive
723} //namespace boost
724
725#include <boost/intrusive/detail/config_end.hpp>
726
727#endif //BOOST_INTRUSIVE_AVLTREE_ALGORITHMS_HPP
728

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