1/////////////////////////////////////////////////////////////////////////////
2//
3// (C) Copyright Ion Gaztanaga 2007-2014
4//
5// Distributed under the Boost Software License, Version 1.0.
6// (See accompanying file LICENSE_1_0.txt or copy at
7// http://www.boost.org/LICENSE_1_0.txt)
8//
9// See http://www.boost.org/libs/intrusive for documentation.
10//
11/////////////////////////////////////////////////////////////////////////////
12// The implementation of splay trees is based on the article and code published
13// in C++ Users Journal "Implementing Splay Trees in C++" (September 1, 2005).
14//
15// The splay code has been modified and (supposedly) improved by Ion Gaztanaga.
16//
17// Here is the copyright notice of the original file containing the splay code:
18//
19// splay_tree.h -- implementation of a STL compatible splay tree.
20//
21// Copyright (c) 2004 Ralf Mattethat
22//
23// Permission to copy, use, modify, sell and distribute this software
24// is granted provided this copyright notice appears in all copies.
25// This software is provided "as is" without express or implied
26// warranty, and with no claim as to its suitability for any purpose.
27//
28/////////////////////////////////////////////////////////////////////////////
29
30#ifndef BOOST_INTRUSIVE_SPLAYTREE_ALGORITHMS_HPP
31#define BOOST_INTRUSIVE_SPLAYTREE_ALGORITHMS_HPP
32
33#include <boost/intrusive/detail/config_begin.hpp>
34#include <boost/intrusive/intrusive_fwd.hpp>
35#include <boost/intrusive/detail/assert.hpp>
36#include <boost/intrusive/detail/algo_type.hpp>
37#include <boost/intrusive/detail/uncast.hpp>
38#include <boost/intrusive/bstree_algorithms.hpp>
39
40#include <cstddef>
41
42#if defined(BOOST_HAS_PRAGMA_ONCE)
43# pragma once
44#endif
45
46namespace boost {
47namespace intrusive {
48
49/// @cond
50namespace detail {
51
52template<class NodeTraits>
53struct splaydown_assemble_and_fix_header
54{
55 typedef typename NodeTraits::node_ptr node_ptr;
56
57 splaydown_assemble_and_fix_header(const node_ptr & t, const node_ptr & header, const node_ptr &leftmost, const node_ptr &rightmost)
58 : t_(t)
59 , null_node_(header)
60 , l_(null_node_)
61 , r_(null_node_)
62 , leftmost_(leftmost)
63 , rightmost_(rightmost)
64 {}
65
66 ~splaydown_assemble_and_fix_header()
67 {
68 this->assemble();
69
70 //Now recover the original header except for the
71 //splayed root node.
72 //"t_" is the current root and "null_node_" is the header node
73 NodeTraits::set_parent(null_node_, t_);
74 NodeTraits::set_parent(t_, null_node_);
75 //Recover leftmost/rightmost pointers
76 NodeTraits::set_left (null_node_, leftmost_);
77 NodeTraits::set_right(null_node_, rightmost_);
78 }
79
80 private:
81
82 void assemble()
83 {
84 //procedure assemble;
85 // left(r), right(l) := right(t), left(t);
86 // left(t), right(t) := right(null), left(null);
87 //end assemble;
88 { // left(r), right(l) := right(t), left(t);
89
90 node_ptr const old_t_left = NodeTraits::get_left(t_);
91 node_ptr const old_t_right = NodeTraits::get_right(t_);
92 NodeTraits::set_right(l_, old_t_left);
93 NodeTraits::set_left (r_, old_t_right);
94 if(old_t_left){
95 NodeTraits::set_parent(old_t_left, l_);
96 }
97 if(old_t_right){
98 NodeTraits::set_parent(old_t_right, r_);
99 }
100 }
101 { // left(t), right(t) := right(null), left(null);
102 node_ptr const null_right = NodeTraits::get_right(null_node_);
103 node_ptr const null_left = NodeTraits::get_left(null_node_);
104 NodeTraits::set_left (t_, null_right);
105 NodeTraits::set_right(t_, null_left);
106 if(null_right){
107 NodeTraits::set_parent(null_right, t_);
108 }
109 if(null_left){
110 NodeTraits::set_parent(null_left, t_);
111 }
112 }
113 }
114
115 public:
116 node_ptr t_, null_node_, l_, r_, leftmost_, rightmost_;
117};
118
119} //namespace detail {
120/// @endcond
121
122//! A splay tree is an implementation of a binary search tree. The tree is
123//! self balancing using the splay algorithm as described in
124//!
125//! "Self-Adjusting Binary Search Trees
126//! by Daniel Dominic Sleator and Robert Endre Tarjan
127//! AT&T Bell Laboratories, Murray Hill, NJ
128//! Journal of the ACM, Vol 32, no 3, July 1985, pp 652-686
129//!
130//! splaytree_algorithms is configured with a NodeTraits class, which encapsulates the
131//! information about the node to be manipulated. NodeTraits must support the
132//! following interface:
133//!
134//! <b>Typedefs</b>:
135//!
136//! <tt>node</tt>: The type of the node that forms the binary search tree
137//!
138//! <tt>node_ptr</tt>: A pointer to a node
139//!
140//! <tt>const_node_ptr</tt>: A pointer to a const node
141//!
142//! <b>Static functions</b>:
143//!
144//! <tt>static node_ptr get_parent(const_node_ptr n);</tt>
145//!
146//! <tt>static void set_parent(node_ptr n, node_ptr parent);</tt>
147//!
148//! <tt>static node_ptr get_left(const_node_ptr n);</tt>
149//!
150//! <tt>static void set_left(node_ptr n, node_ptr left);</tt>
151//!
152//! <tt>static node_ptr get_right(const_node_ptr n);</tt>
153//!
154//! <tt>static void set_right(node_ptr n, node_ptr right);</tt>
155template<class NodeTraits>
156class splaytree_algorithms
157 #ifndef BOOST_INTRUSIVE_DOXYGEN_INVOKED
158 : public bstree_algorithms<NodeTraits>
159 #endif
160{
161 /// @cond
162 private:
163 typedef bstree_algorithms<NodeTraits> bstree_algo;
164 /// @endcond
165
166 public:
167 typedef typename NodeTraits::node node;
168 typedef NodeTraits node_traits;
169 typedef typename NodeTraits::node_ptr node_ptr;
170 typedef typename NodeTraits::const_node_ptr const_node_ptr;
171
172 //! This type is the information that will be
173 //! filled by insert_unique_check
174 typedef typename bstree_algo::insert_commit_data insert_commit_data;
175
176 public:
177 #ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
178 //! @copydoc ::boost::intrusive::bstree_algorithms::get_header(const const_node_ptr&)
179 static node_ptr get_header(const const_node_ptr & n);
180
181 //! @copydoc ::boost::intrusive::bstree_algorithms::begin_node
182 static node_ptr begin_node(const const_node_ptr & header);
183
184 //! @copydoc ::boost::intrusive::bstree_algorithms::end_node
185 static node_ptr end_node(const const_node_ptr & header);
186
187 //! @copydoc ::boost::intrusive::bstree_algorithms::swap_tree
188 static void swap_tree(const node_ptr & header1, const node_ptr & header2);
189
190 //! @copydoc ::boost::intrusive::bstree_algorithms::swap_nodes(const node_ptr&,const node_ptr&)
191 static void swap_nodes(const node_ptr & node1, const node_ptr & node2);
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 //! @copydoc ::boost::intrusive::bstree_algorithms::replace_node(const node_ptr&,const node_ptr&)
197 static void replace_node(const node_ptr & node_to_be_replaced, const node_ptr & new_node);
198
199 //! @copydoc ::boost::intrusive::bstree_algorithms::replace_node(const node_ptr&,const node_ptr&,const node_ptr&)
200 static void replace_node(const node_ptr & node_to_be_replaced, const node_ptr & header, const node_ptr & new_node);
201
202 //! @copydoc ::boost::intrusive::bstree_algorithms::unlink(const node_ptr&)
203 static void unlink(const node_ptr & node);
204
205 //! @copydoc ::boost::intrusive::bstree_algorithms::unlink_leftmost_without_rebalance
206 static node_ptr unlink_leftmost_without_rebalance(const node_ptr & header);
207
208 //! @copydoc ::boost::intrusive::bstree_algorithms::unique(const const_node_ptr&)
209 static bool unique(const const_node_ptr & node);
210
211 //! @copydoc ::boost::intrusive::bstree_algorithms::size(const const_node_ptr&)
212 static std::size_t size(const const_node_ptr & header);
213
214 //! @copydoc ::boost::intrusive::bstree_algorithms::next_node(const node_ptr&)
215 static node_ptr next_node(const node_ptr & node);
216
217 //! @copydoc ::boost::intrusive::bstree_algorithms::prev_node(const node_ptr&)
218 static node_ptr prev_node(const node_ptr & node);
219
220 //! @copydoc ::boost::intrusive::bstree_algorithms::init(const node_ptr&)
221 static void init(const node_ptr & node);
222
223 //! @copydoc ::boost::intrusive::bstree_algorithms::init_header(const node_ptr&)
224 static void init_header(const node_ptr & header);
225
226 #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
227
228 //! @copydoc ::boost::intrusive::bstree_algorithms::erase(const node_ptr&,const node_ptr&)
229 //! Additional notes: the previous node of z is splayed to speed up range deletions.
230 static void erase(const node_ptr & header, const node_ptr & z)
231 {
232 //posibility 1
233 if(NodeTraits::get_left(z)){
234 splay_up(node: bstree_algo::prev_node(z), header);
235 }
236
237 //possibility 2
238 //if(NodeTraits::get_left(z)){
239 // node_ptr l = NodeTraits::get_left(z);
240 // splay_up(l, header);
241 //}
242
243 //if(NodeTraits::get_left(z)){
244 // node_ptr l = bstree_algo::prev_node(z);
245 // splay_up_impl(l, z);
246 //}
247
248 //possibility 4
249 //splay_up(z, header);
250
251 bstree_algo::erase(header, z);
252 }
253
254 #ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
255 //! @copydoc ::boost::intrusive::bstree_algorithms::clone(const const_node_ptr&,const node_ptr&,Cloner,Disposer)
256 template <class Cloner, class Disposer>
257 static void clone
258 (const const_node_ptr & source_header, const node_ptr & target_header, Cloner cloner, Disposer disposer);
259
260 //! @copydoc ::boost::intrusive::bstree_algorithms::clear_and_dispose(const node_ptr&,Disposer)
261 template<class Disposer>
262 static void clear_and_dispose(const node_ptr & header, Disposer disposer);
263
264 #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
265 //! @copydoc ::boost::intrusive::bstree_algorithms::count(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
266 //! Additional notes: an element with key `key` is splayed.
267 template<class KeyType, class KeyNodePtrCompare>
268 static std::size_t count
269 (const node_ptr & header, const KeyType &key, KeyNodePtrCompare comp)
270 {
271 std::pair<node_ptr, node_ptr> ret = equal_range(header, key, comp);
272 std::size_t n = 0;
273 while(ret.first != ret.second){
274 ++n;
275 ret.first = next_node(ret.first);
276 }
277 return n;
278 }
279
280 //! @copydoc ::boost::intrusive::bstree_algorithms::count(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
281 //! Additional note: no splaying is performed
282 template<class KeyType, class KeyNodePtrCompare>
283 static std::size_t count
284 (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp)
285 { return bstree_algo::count(header, key, comp); }
286
287 //! @copydoc ::boost::intrusive::bstree_algorithms::lower_bound(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
288 //! Additional notes: the first node of the range is splayed.
289 template<class KeyType, class KeyNodePtrCompare>
290 static node_ptr lower_bound
291 (const node_ptr & header, const KeyType &key, KeyNodePtrCompare comp)
292 {
293 splay_down(detail::uncast(header), key, comp);
294 node_ptr y = bstree_algo::lower_bound(header, key, comp);
295 //splay_up(y, detail::uncast(header));
296 return y;
297 }
298
299 //! @copydoc ::boost::intrusive::bstree_algorithms::lower_bound(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
300 //! Additional note: no splaying is performed
301 template<class KeyType, class KeyNodePtrCompare>
302 static node_ptr lower_bound
303 (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp)
304 { return bstree_algo::lower_bound(header, key, comp); }
305
306 //! @copydoc ::boost::intrusive::bstree_algorithms::upper_bound(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
307 //! Additional notes: the first node of the range is splayed.
308 template<class KeyType, class KeyNodePtrCompare>
309 static node_ptr upper_bound
310 (const node_ptr & header, const KeyType &key, KeyNodePtrCompare comp)
311 {
312 splay_down(detail::uncast(header), key, comp);
313 node_ptr y = bstree_algo::upper_bound(header, key, comp);
314 //splay_up(y, detail::uncast(header));
315 return y;
316 }
317
318 //! @copydoc ::boost::intrusive::bstree_algorithms::upper_bound(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
319 //! Additional note: no splaying is performed
320 template<class KeyType, class KeyNodePtrCompare>
321 static node_ptr upper_bound
322 (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp)
323 { return bstree_algo::upper_bound(header, key, comp); }
324
325 //! @copydoc ::boost::intrusive::bstree_algorithms::find(const const_node_ptr&, const KeyType&,KeyNodePtrCompare)
326 //! Additional notes: the found node of the lower bound is splayed.
327 template<class KeyType, class KeyNodePtrCompare>
328 static node_ptr find
329 (const node_ptr & header, const KeyType &key, KeyNodePtrCompare comp)
330 {
331 splay_down(detail::uncast(header), key, comp);
332 return bstree_algo::find(header, key, comp);
333 }
334
335 //! @copydoc ::boost::intrusive::bstree_algorithms::find(const const_node_ptr&, const KeyType&,KeyNodePtrCompare)
336 //! Additional note: no splaying is performed
337 template<class KeyType, class KeyNodePtrCompare>
338 static node_ptr find
339 (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp)
340 { return bstree_algo::find(header, key, comp); }
341
342 //! @copydoc ::boost::intrusive::bstree_algorithms::equal_range(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
343 //! Additional notes: the first node of the range is splayed.
344 template<class KeyType, class KeyNodePtrCompare>
345 static std::pair<node_ptr, node_ptr> equal_range
346 (const node_ptr & header, const KeyType &key, KeyNodePtrCompare comp)
347 {
348 splay_down(detail::uncast(header), key, comp);
349 std::pair<node_ptr, node_ptr> ret = bstree_algo::equal_range(header, key, comp);
350 //splay_up(ret.first, detail::uncast(header));
351 return ret;
352 }
353
354 //! @copydoc ::boost::intrusive::bstree_algorithms::equal_range(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
355 //! Additional note: no splaying is performed
356 template<class KeyType, class KeyNodePtrCompare>
357 static std::pair<node_ptr, node_ptr> equal_range
358 (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp)
359 { return bstree_algo::equal_range(header, key, comp); }
360
361 //! @copydoc ::boost::intrusive::bstree_algorithms::lower_bound_range(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
362 //! Additional notes: the first node of the range is splayed.
363 template<class KeyType, class KeyNodePtrCompare>
364 static std::pair<node_ptr, node_ptr> lower_bound_range
365 (const node_ptr & header, const KeyType &key, KeyNodePtrCompare comp)
366 {
367 splay_down(detail::uncast(header), key, comp);
368 std::pair<node_ptr, node_ptr> ret = bstree_algo::lower_bound_range(header, key, comp);
369 //splay_up(ret.first, detail::uncast(header));
370 return ret;
371 }
372
373 //! @copydoc ::boost::intrusive::bstree_algorithms::lower_bound_range(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
374 //! Additional note: no splaying is performed
375 template<class KeyType, class KeyNodePtrCompare>
376 static std::pair<node_ptr, node_ptr> lower_bound_range
377 (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp)
378 { return bstree_algo::lower_bound_range(header, key, comp); }
379
380 //! @copydoc ::boost::intrusive::bstree_algorithms::bounded_range(const const_node_ptr&,const KeyType&,const KeyType&,KeyNodePtrCompare,bool,bool)
381 //! Additional notes: the first node of the range is splayed.
382 template<class KeyType, class KeyNodePtrCompare>
383 static std::pair<node_ptr, node_ptr> bounded_range
384 (const node_ptr & header, const KeyType &lower_key, const KeyType &upper_key, KeyNodePtrCompare comp
385 , bool left_closed, bool right_closed)
386 {
387 splay_down(detail::uncast(header), lower_key, comp);
388 std::pair<node_ptr, node_ptr> ret =
389 bstree_algo::bounded_range(header, lower_key, upper_key, comp, left_closed, right_closed);
390 //splay_up(ret.first, detail::uncast(header));
391 return ret;
392 }
393
394 //! @copydoc ::boost::intrusive::bstree_algorithms::bounded_range(const const_node_ptr&,const KeyType&,const KeyType&,KeyNodePtrCompare,bool,bool)
395 //! Additional note: no splaying is performed
396 template<class KeyType, class KeyNodePtrCompare>
397 static std::pair<node_ptr, node_ptr> bounded_range
398 (const const_node_ptr & header, const KeyType &lower_key, const KeyType &upper_key, KeyNodePtrCompare comp
399 , bool left_closed, bool right_closed)
400 { return bstree_algo::bounded_range(header, lower_key, upper_key, comp, left_closed, right_closed); }
401
402 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal_upper_bound(const node_ptr&,const node_ptr&,NodePtrCompare)
403 //! Additional note: the inserted node is splayed
404 template<class NodePtrCompare>
405 static node_ptr insert_equal_upper_bound
406 (const node_ptr & header, const node_ptr & new_node, NodePtrCompare comp)
407 {
408 splay_down(header, new_node, comp);
409 return bstree_algo::insert_equal_upper_bound(header, new_node, comp);
410 }
411
412 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal_lower_bound(const node_ptr&,const node_ptr&,NodePtrCompare)
413 //! Additional note: the inserted node is splayed
414 template<class NodePtrCompare>
415 static node_ptr insert_equal_lower_bound
416 (const node_ptr & header, const node_ptr & new_node, NodePtrCompare comp)
417 {
418 splay_down(header, new_node, comp);
419 return bstree_algo::insert_equal_lower_bound(header, new_node, comp);
420 }
421
422 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal(const node_ptr&,const node_ptr&,const node_ptr&,NodePtrCompare)
423 //! Additional note: the inserted node is splayed
424 template<class NodePtrCompare>
425 static node_ptr insert_equal
426 (const node_ptr & header, const node_ptr & hint, const node_ptr & new_node, NodePtrCompare comp)
427 {
428 splay_down(header, new_node, comp);
429 return bstree_algo::insert_equal(header, hint, new_node, comp);
430 }
431
432 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_before(const node_ptr&,const node_ptr&,const node_ptr&)
433 //! Additional note: the inserted node is splayed
434 static node_ptr insert_before
435 (const node_ptr & header, const node_ptr & pos, const node_ptr & new_node)
436 {
437 bstree_algo::insert_before(header, pos, new_node);
438 splay_up(node: new_node, header);
439 return new_node;
440 }
441
442 //! @copydoc ::boost::intrusive::bstree_algorithms::push_back(const node_ptr&,const node_ptr&)
443 //! Additional note: the inserted node is splayed
444 static void push_back(const node_ptr & header, const node_ptr & new_node)
445 {
446 bstree_algo::push_back(header, new_node);
447 splay_up(node: new_node, header);
448 }
449
450 //! @copydoc ::boost::intrusive::bstree_algorithms::push_front(const node_ptr&,const node_ptr&)
451 //! Additional note: the inserted node is splayed
452 static void push_front(const node_ptr & header, const node_ptr & new_node)
453 {
454 bstree_algo::push_front(header, new_node);
455 splay_up(node: new_node, header);
456 }
457
458 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_check(const const_node_ptr&,const KeyType&,KeyNodePtrCompare,insert_commit_data&)
459 //! Additional note: nodes with the given key are splayed
460 template<class KeyType, class KeyNodePtrCompare>
461 static std::pair<node_ptr, bool> insert_unique_check
462 (const node_ptr & header, const KeyType &key
463 ,KeyNodePtrCompare comp, insert_commit_data &commit_data)
464 {
465 splay_down(header, key, comp);
466 return bstree_algo::insert_unique_check(header, key, comp, commit_data);
467 }
468
469 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_check(const const_node_ptr&,const node_ptr&,const KeyType&,KeyNodePtrCompare,insert_commit_data&)
470 //! Additional note: nodes with the given key are splayed
471 template<class KeyType, class KeyNodePtrCompare>
472 static std::pair<node_ptr, bool> insert_unique_check
473 (const node_ptr & header, const node_ptr &hint, const KeyType &key
474 ,KeyNodePtrCompare comp, insert_commit_data &commit_data)
475 {
476 splay_down(header, key, comp);
477 return bstree_algo::insert_unique_check(header, hint, key, comp, commit_data);
478 }
479
480 #ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
481 //! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_commit(const node_ptr&,const node_ptr&,const insert_commit_data&)
482 static void insert_unique_commit
483 (const node_ptr & header, const node_ptr & new_value, const insert_commit_data &commit_data);
484
485 //! @copydoc ::boost::intrusive::bstree_algorithms::is_header
486 static bool is_header(const const_node_ptr & p);
487
488 //! @copydoc ::boost::intrusive::bstree_algorithms::rebalance
489 static void rebalance(const node_ptr & header);
490
491 //! @copydoc ::boost::intrusive::bstree_algorithms::rebalance_subtree
492 static node_ptr rebalance_subtree(const node_ptr & old_root);
493
494 #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
495
496 // bottom-up splay, use data_ as parent for n | complexity : logarithmic | exception : nothrow
497 static void splay_up(const node_ptr & node, const node_ptr & header)
498 { priv_splay_up<true>(node, header); }
499
500 // top-down splay | complexity : logarithmic | exception : strong, note A
501 template<class KeyType, class KeyNodePtrCompare>
502 static node_ptr splay_down(const node_ptr & header, const KeyType &key, KeyNodePtrCompare comp, bool *pfound = 0)
503 { return priv_splay_down<true>(header, key, comp, pfound); }
504
505 private:
506
507 /// @cond
508
509 // bottom-up splay, use data_ as parent for n | complexity : logarithmic | exception : nothrow
510 template<bool SimpleSplay>
511 static void priv_splay_up(const node_ptr & node, const node_ptr & header)
512 {
513 // If (node == header) do a splay for the right most node instead
514 // this is to boost performance of equal_range/count on equivalent containers in the case
515 // where there are many equal elements at the end
516 node_ptr n((node == header) ? NodeTraits::get_right(header) : node);
517 node_ptr t(header);
518
519 if( n == t ) return;
520
521 for( ;; ){
522 node_ptr p(NodeTraits::get_parent(n));
523 node_ptr g(NodeTraits::get_parent(p));
524
525 if( p == t ) break;
526
527 if( g == t ){
528 // zig
529 rotate(n);
530 }
531 else if ((NodeTraits::get_left(p) == n && NodeTraits::get_left(g) == p) ||
532 (NodeTraits::get_right(p) == n && NodeTraits::get_right(g) == p) ){
533 // zig-zig
534 rotate(n: p);
535 rotate(n);
536 }
537 else {
538 // zig-zag
539 rotate(n);
540 if(!SimpleSplay){
541 rotate(n);
542 }
543 }
544 }
545 }
546
547 template<bool SimpleSplay, class KeyType, class KeyNodePtrCompare>
548 static node_ptr priv_splay_down(const node_ptr & header, const KeyType &key, KeyNodePtrCompare comp, bool *pfound = 0)
549 {
550 //Most splay tree implementations use a dummy/null node to implement.
551 //this function. This has some problems for a generic library like Intrusive:
552 //
553 // * The node might not have a default constructor.
554 // * The default constructor could throw.
555 //
556 //We already have a header node. Leftmost and rightmost nodes of the tree
557 //are not changed when splaying (because the invariants of the tree don't
558 //change) We can back up them, use the header as the null node and
559 //reassign old values after the function has been completed.
560 node_ptr const old_root = NodeTraits::get_parent(header);
561 node_ptr const leftmost = NodeTraits::get_left(header);
562 node_ptr const rightmost = NodeTraits::get_right(header);
563 if(leftmost == rightmost){ //Empty or unique node
564 if(pfound){
565 *pfound = old_root && !comp(key, old_root) && !comp(old_root, key);
566 }
567 return old_root ? old_root : header;
568 }
569 else{
570 //Initialize "null node" (the header in our case)
571 NodeTraits::set_left (header, node_ptr());
572 NodeTraits::set_right(header, node_ptr());
573 //Class that will backup leftmost/rightmost from header, commit the assemble(),
574 //and will restore leftmost/rightmost to header even if "comp" throws
575 detail::splaydown_assemble_and_fix_header<NodeTraits> commit(old_root, header, leftmost, rightmost);
576 bool found = false;
577
578 for( ;; ){
579 if(comp(key, commit.t_)){
580 node_ptr const t_left = NodeTraits::get_left(commit.t_);
581 if(!t_left)
582 break;
583 if(comp(key, t_left)){
584 bstree_algo::rotate_right_no_parent_fix(commit.t_, t_left);
585 commit.t_ = t_left;
586 if( !NodeTraits::get_left(commit.t_) )
587 break;
588 link_right(t&: commit.t_, r&: commit.r_);
589 }
590 else{
591 link_right(t&: commit.t_, r&: commit.r_);
592 if(!SimpleSplay && comp(t_left, key)){
593 if( !NodeTraits::get_right(commit.t_) )
594 break;
595 link_left(t&: commit.t_, l&: commit.l_);
596 }
597 }
598 }
599 else if(comp(commit.t_, key)){
600 node_ptr const t_right = NodeTraits::get_right(commit.t_);
601 if(!t_right)
602 break;
603
604 if(comp(t_right, key)){
605 bstree_algo::rotate_left_no_parent_fix(commit.t_, t_right);
606 commit.t_ = t_right;
607 if( !NodeTraits::get_right(commit.t_) )
608 break;
609 link_left(t&: commit.t_, l&: commit.l_);
610 }
611 else{
612 link_left(t&: commit.t_, l&: commit.l_);
613 if(!SimpleSplay && comp(key, t_right)){
614 if( !NodeTraits::get_left(commit.t_) )
615 break;
616 link_right(t&: commit.t_, r&: commit.r_);
617 }
618 }
619 }
620 else{
621 found = true;
622 break;
623 }
624 }
625
626 //commit.~splaydown_assemble_and_fix_header<NodeTraits>() will first
627 //"assemble()" + link the new root & recover header's leftmost & rightmost
628 if(pfound){
629 *pfound = found;
630 }
631 return commit.t_;
632 }
633 }
634
635 // break link to left child node and attach it to left tree pointed to by l | complexity : constant | exception : nothrow
636 static void link_left(node_ptr & t, node_ptr & l)
637 {
638 //procedure link_left;
639 // t, l, right(l) := right(t), t, t
640 //end link_left
641 NodeTraits::set_right(l, t);
642 NodeTraits::set_parent(t, l);
643 l = t;
644 t = NodeTraits::get_right(t);
645 }
646
647 // break link to right child node and attach it to right tree pointed to by r | complexity : constant | exception : nothrow
648 static void link_right(node_ptr & t, node_ptr & r)
649 {
650 //procedure link_right;
651 // t, r, left(r) := left(t), t, t
652 //end link_right;
653 NodeTraits::set_left(r, t);
654 NodeTraits::set_parent(t, r);
655 r = t;
656 t = NodeTraits::get_left(t);
657 }
658
659 // rotate n with its parent | complexity : constant | exception : nothrow
660 static void rotate(const node_ptr & n)
661 {
662 //procedure rotate_left;
663 // t, right(t), left(right(t)) := right(t), left(right(t)), t
664 //end rotate_left;
665 node_ptr p = NodeTraits::get_parent(n);
666 node_ptr g = NodeTraits::get_parent(p);
667 //Test if g is header before breaking tree
668 //invariants that would make is_header invalid
669 bool g_is_header = bstree_algo::is_header(g);
670
671 if(NodeTraits::get_left(p) == n){
672 NodeTraits::set_left(p, NodeTraits::get_right(n));
673 if(NodeTraits::get_left(p))
674 NodeTraits::set_parent(NodeTraits::get_left(p), p);
675 NodeTraits::set_right(n, p);
676 }
677 else{ // must be ( p->right == n )
678 NodeTraits::set_right(p, NodeTraits::get_left(n));
679 if(NodeTraits::get_right(p))
680 NodeTraits::set_parent(NodeTraits::get_right(p), p);
681 NodeTraits::set_left(n, p);
682 }
683
684 NodeTraits::set_parent(p, n);
685 NodeTraits::set_parent(n, g);
686
687 if(g_is_header){
688 if(NodeTraits::get_parent(g) == p)
689 NodeTraits::set_parent(g, n);
690 else{//must be ( g->right == p )
691 BOOST_INTRUSIVE_INVARIANT_ASSERT(false);
692 NodeTraits::set_right(g, n);
693 }
694 }
695 else{
696 if(NodeTraits::get_left(g) == p)
697 NodeTraits::set_left(g, n);
698 else //must be ( g->right == p )
699 NodeTraits::set_right(g, n);
700 }
701 }
702
703 /// @endcond
704};
705
706/// @cond
707
708template<class NodeTraits>
709struct get_algo<SplayTreeAlgorithms, NodeTraits>
710{
711 typedef splaytree_algorithms<NodeTraits> type;
712};
713
714template <class ValueTraits, class NodePtrCompare, class ExtraChecker>
715struct get_node_checker<SplayTreeAlgorithms, ValueTraits, NodePtrCompare, ExtraChecker>
716{
717 typedef detail::bstree_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_SPLAYTREE_ALGORITHMS_HPP
728

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