1 // RB tree utilities implementation -*- C++ -*-
3 // Copyright (C) 2003, 2005, 2009 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
27 * Copyright (c) 1996,1997
28 * Silicon Graphics Computer Systems, Inc.
30 * Permission to use, copy, modify, distribute and sell this software
31 * and its documentation for any purpose is hereby granted without fee,
32 * provided that the above copyright notice appear in all copies and
33 * that both that copyright notice and this permission notice appear
34 * in supporting documentation. Silicon Graphics makes no
35 * representations about the suitability of this software for any
36 * purpose. It is provided "as is" without express or implied warranty.
40 * Hewlett-Packard Company
42 * Permission to use, copy, modify, distribute and sell this software
43 * and its documentation for any purpose is hereby granted without fee,
44 * provided that the above copyright notice appear in all copies and
45 * that both that copyright notice and this permission notice appear
46 * in supporting documentation. Hewlett-Packard Company makes no
47 * representations about the suitability of this software for any
48 * purpose. It is provided "as is" without express or implied warranty.
53 #include <bits/stl_tree.h>
55 namespace std _GLIBCXX_VISIBILITY(default)
57 _GLIBCXX_BEGIN_NAMESPACE_VERSION
60 _Rb_tree_increment(_Rb_tree_node_base* __x) throw ()
62 if (__x->_M_right != 0)
65 while (__x->_M_left != 0)
70 _Rb_tree_node_base* __y = __x->_M_parent;
71 while (__x == __y->_M_right)
76 if (__x->_M_right != __y)
82 const _Rb_tree_node_base*
83 _Rb_tree_increment(const _Rb_tree_node_base* __x) throw ()
85 return _Rb_tree_increment(const_cast<_Rb_tree_node_base*>(__x));
89 _Rb_tree_decrement(_Rb_tree_node_base* __x) throw ()
91 if (__x->_M_color == _S_red
92 && __x->_M_parent->_M_parent == __x)
94 else if (__x->_M_left != 0)
96 _Rb_tree_node_base* __y = __x->_M_left;
97 while (__y->_M_right != 0)
103 _Rb_tree_node_base* __y = __x->_M_parent;
104 while (__x == __y->_M_left)
107 __y = __y->_M_parent;
114 const _Rb_tree_node_base*
115 _Rb_tree_decrement(const _Rb_tree_node_base* __x) throw ()
117 return _Rb_tree_decrement(const_cast<_Rb_tree_node_base*>(__x));
121 local_Rb_tree_rotate_left(_Rb_tree_node_base* const __x,
122 _Rb_tree_node_base*& __root)
124 _Rb_tree_node_base* const __y = __x->_M_right;
126 __x->_M_right = __y->_M_left;
127 if (__y->_M_left !=0)
128 __y->_M_left->_M_parent = __x;
129 __y->_M_parent = __x->_M_parent;
133 else if (__x == __x->_M_parent->_M_left)
134 __x->_M_parent->_M_left = __y;
136 __x->_M_parent->_M_right = __y;
138 __x->_M_parent = __y;
141 /* Static keyword was missing on _Rb_tree_rotate_left.
142 Export the symbol for backward compatibility until
145 _Rb_tree_rotate_left(_Rb_tree_node_base* const __x,
146 _Rb_tree_node_base*& __root)
148 local_Rb_tree_rotate_left (__x, __root);
152 local_Rb_tree_rotate_right(_Rb_tree_node_base* const __x,
153 _Rb_tree_node_base*& __root)
155 _Rb_tree_node_base* const __y = __x->_M_left;
157 __x->_M_left = __y->_M_right;
158 if (__y->_M_right != 0)
159 __y->_M_right->_M_parent = __x;
160 __y->_M_parent = __x->_M_parent;
164 else if (__x == __x->_M_parent->_M_right)
165 __x->_M_parent->_M_right = __y;
167 __x->_M_parent->_M_left = __y;
169 __x->_M_parent = __y;
172 /* Static keyword was missing on _Rb_tree_rotate_right
173 Export the symbol for backward compatibility until
176 _Rb_tree_rotate_right(_Rb_tree_node_base* const __x,
177 _Rb_tree_node_base*& __root)
179 local_Rb_tree_rotate_right (__x, __root);
183 _Rb_tree_insert_and_rebalance(const bool __insert_left,
184 _Rb_tree_node_base* __x,
185 _Rb_tree_node_base* __p,
186 _Rb_tree_node_base& __header) throw ()
188 _Rb_tree_node_base *& __root = __header._M_parent;
190 // Initialize fields in new node to insert.
191 __x->_M_parent = __p;
194 __x->_M_color = _S_red;
197 // Make new node child of parent and maintain root, leftmost and
199 // N.B. First node is always inserted left.
202 __p->_M_left = __x; // also makes leftmost = __x when __p == &__header
204 if (__p == &__header)
206 __header._M_parent = __x;
207 __header._M_right = __x;
209 else if (__p == __header._M_left)
210 __header._M_left = __x; // maintain leftmost pointing to min node
216 if (__p == __header._M_right)
217 __header._M_right = __x; // maintain rightmost pointing to max node
221 && __x->_M_parent->_M_color == _S_red)
223 _Rb_tree_node_base* const __xpp = __x->_M_parent->_M_parent;
225 if (__x->_M_parent == __xpp->_M_left)
227 _Rb_tree_node_base* const __y = __xpp->_M_right;
228 if (__y && __y->_M_color == _S_red)
230 __x->_M_parent->_M_color = _S_black;
231 __y->_M_color = _S_black;
232 __xpp->_M_color = _S_red;
237 if (__x == __x->_M_parent->_M_right)
239 __x = __x->_M_parent;
240 local_Rb_tree_rotate_left(__x, __root);
242 __x->_M_parent->_M_color = _S_black;
243 __xpp->_M_color = _S_red;
244 local_Rb_tree_rotate_right(__xpp, __root);
249 _Rb_tree_node_base* const __y = __xpp->_M_left;
250 if (__y && __y->_M_color == _S_red)
252 __x->_M_parent->_M_color = _S_black;
253 __y->_M_color = _S_black;
254 __xpp->_M_color = _S_red;
259 if (__x == __x->_M_parent->_M_left)
261 __x = __x->_M_parent;
262 local_Rb_tree_rotate_right(__x, __root);
264 __x->_M_parent->_M_color = _S_black;
265 __xpp->_M_color = _S_red;
266 local_Rb_tree_rotate_left(__xpp, __root);
270 __root->_M_color = _S_black;
274 _Rb_tree_rebalance_for_erase(_Rb_tree_node_base* const __z,
275 _Rb_tree_node_base& __header) throw ()
277 _Rb_tree_node_base *& __root = __header._M_parent;
278 _Rb_tree_node_base *& __leftmost = __header._M_left;
279 _Rb_tree_node_base *& __rightmost = __header._M_right;
280 _Rb_tree_node_base* __y = __z;
281 _Rb_tree_node_base* __x = 0;
282 _Rb_tree_node_base* __x_parent = 0;
284 if (__y->_M_left == 0) // __z has at most one non-null child. y == z.
285 __x = __y->_M_right; // __x might be null.
287 if (__y->_M_right == 0) // __z has exactly one non-null child. y == z.
288 __x = __y->_M_left; // __x is not null.
291 // __z has two non-null children. Set __y to
292 __y = __y->_M_right; // __z's successor. __x might be null.
293 while (__y->_M_left != 0)
299 // relink y in place of z. y is z's successor
300 __z->_M_left->_M_parent = __y;
301 __y->_M_left = __z->_M_left;
302 if (__y != __z->_M_right)
304 __x_parent = __y->_M_parent;
305 if (__x) __x->_M_parent = __y->_M_parent;
306 __y->_M_parent->_M_left = __x; // __y must be a child of _M_left
307 __y->_M_right = __z->_M_right;
308 __z->_M_right->_M_parent = __y;
314 else if (__z->_M_parent->_M_left == __z)
315 __z->_M_parent->_M_left = __y;
317 __z->_M_parent->_M_right = __y;
318 __y->_M_parent = __z->_M_parent;
319 std::swap(__y->_M_color, __z->_M_color);
321 // __y now points to node to be actually deleted
325 __x_parent = __y->_M_parent;
327 __x->_M_parent = __y->_M_parent;
331 if (__z->_M_parent->_M_left == __z)
332 __z->_M_parent->_M_left = __x;
334 __z->_M_parent->_M_right = __x;
335 if (__leftmost == __z)
337 if (__z->_M_right == 0) // __z->_M_left must be null also
338 __leftmost = __z->_M_parent;
339 // makes __leftmost == _M_header if __z == __root
341 __leftmost = _Rb_tree_node_base::_S_minimum(__x);
343 if (__rightmost == __z)
345 if (__z->_M_left == 0) // __z->_M_right must be null also
346 __rightmost = __z->_M_parent;
347 // makes __rightmost == _M_header if __z == __root
348 else // __x == __z->_M_left
349 __rightmost = _Rb_tree_node_base::_S_maximum(__x);
352 if (__y->_M_color != _S_red)
354 while (__x != __root && (__x == 0 || __x->_M_color == _S_black))
355 if (__x == __x_parent->_M_left)
357 _Rb_tree_node_base* __w = __x_parent->_M_right;
358 if (__w->_M_color == _S_red)
360 __w->_M_color = _S_black;
361 __x_parent->_M_color = _S_red;
362 local_Rb_tree_rotate_left(__x_parent, __root);
363 __w = __x_parent->_M_right;
365 if ((__w->_M_left == 0 ||
366 __w->_M_left->_M_color == _S_black) &&
367 (__w->_M_right == 0 ||
368 __w->_M_right->_M_color == _S_black))
370 __w->_M_color = _S_red;
372 __x_parent = __x_parent->_M_parent;
376 if (__w->_M_right == 0
377 || __w->_M_right->_M_color == _S_black)
379 __w->_M_left->_M_color = _S_black;
380 __w->_M_color = _S_red;
381 local_Rb_tree_rotate_right(__w, __root);
382 __w = __x_parent->_M_right;
384 __w->_M_color = __x_parent->_M_color;
385 __x_parent->_M_color = _S_black;
387 __w->_M_right->_M_color = _S_black;
388 local_Rb_tree_rotate_left(__x_parent, __root);
394 // same as above, with _M_right <-> _M_left.
395 _Rb_tree_node_base* __w = __x_parent->_M_left;
396 if (__w->_M_color == _S_red)
398 __w->_M_color = _S_black;
399 __x_parent->_M_color = _S_red;
400 local_Rb_tree_rotate_right(__x_parent, __root);
401 __w = __x_parent->_M_left;
403 if ((__w->_M_right == 0 ||
404 __w->_M_right->_M_color == _S_black) &&
405 (__w->_M_left == 0 ||
406 __w->_M_left->_M_color == _S_black))
408 __w->_M_color = _S_red;
410 __x_parent = __x_parent->_M_parent;
414 if (__w->_M_left == 0 || __w->_M_left->_M_color == _S_black)
416 __w->_M_right->_M_color = _S_black;
417 __w->_M_color = _S_red;
418 local_Rb_tree_rotate_left(__w, __root);
419 __w = __x_parent->_M_left;
421 __w->_M_color = __x_parent->_M_color;
422 __x_parent->_M_color = _S_black;
424 __w->_M_left->_M_color = _S_black;
425 local_Rb_tree_rotate_right(__x_parent, __root);
429 if (__x) __x->_M_color = _S_black;
435 _Rb_tree_black_count(const _Rb_tree_node_base* __node,
436 const _Rb_tree_node_base* __root) throw ()
440 unsigned int __sum = 0;
443 if (__node->_M_color == _S_black)
445 if (__node == __root)
447 __node = __node->_M_parent;
453 _GLIBCXX_END_NAMESPACE_VERSION