libstdc++
pairing_heap_/erase_fn_imps.hpp
Go to the documentation of this file.
1 // -*- C++ -*-
2 
3 // Copyright (C) 2005-2017 Free Software Foundation, Inc.
4 //
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 terms
7 // of the GNU General Public License as published by the Free Software
8 // Foundation; either version 3, or (at your option) any later
9 // version.
10 
11 // This library is distributed in the hope that it will be useful, but
12 // WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 // General Public License for more details.
15 
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.
19 
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/>.
24 
25 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
26 
27 // Permission to use, copy, modify, sell, and distribute this software
28 // is hereby granted without fee, provided that the above copyright
29 // notice appears in all copies, and that both that copyright notice
30 // and this permission notice appear in supporting documentation. None
31 // of the above authors, nor IBM Haifa Research Laboratories, make any
32 // representation about the suitability of this software for any
33 // purpose. It is provided "as is" without express or implied
34 // warranty.
35 
36 /**
37  * @file pairing_heap_/erase_fn_imps.hpp
38  * Contains an implementation class for a pairing heap.
39  */
40 
41 PB_DS_CLASS_T_DEC
42 void
43 PB_DS_CLASS_C_DEC::
44 pop()
45 {
46  PB_DS_ASSERT_VALID((*this))
47  _GLIBCXX_DEBUG_ASSERT(!base_type::empty());
48 
49  node_pointer p_new_root = join_node_children(base_type::m_p_root);
50  PB_DS_ASSERT_NODE_CONSISTENT(p_new_root, false)
51  if (p_new_root != 0)
52  p_new_root->m_p_prev_or_parent = 0;
53 
54  base_type::actual_erase_node(base_type::m_p_root);
55  base_type::m_p_root = p_new_root;
56  PB_DS_ASSERT_VALID((*this))
57 }
58 
59 PB_DS_CLASS_T_DEC
60 void
61 PB_DS_CLASS_C_DEC::
62 erase(point_iterator it)
63 {
64  PB_DS_ASSERT_VALID((*this))
65  _GLIBCXX_DEBUG_ASSERT(!base_type::empty());
66  remove_node(it.m_p_nd);
67  base_type::actual_erase_node(it.m_p_nd);
68  PB_DS_ASSERT_VALID((*this))
69 }
70 
71 PB_DS_CLASS_T_DEC
72 void
73 PB_DS_CLASS_C_DEC::
74 remove_node(node_pointer p_nd)
75 {
76  PB_DS_ASSERT_VALID((*this))
77  _GLIBCXX_DEBUG_ASSERT(!base_type::empty());
78  node_pointer p_new_child = join_node_children(p_nd);
79 
80  PB_DS_ASSERT_NODE_CONSISTENT(p_new_child, false)
81 
82  if (p_nd == base_type::m_p_root)
83  {
84  if (p_new_child != 0)
85  p_new_child->m_p_prev_or_parent = 0;
86  base_type::m_p_root = p_new_child;
87  PB_DS_ASSERT_NODE_CONSISTENT(base_type::m_p_root, false)
88  return;
89  }
90 
91  _GLIBCXX_DEBUG_ASSERT(p_nd->m_p_prev_or_parent != 0);
92  if (p_nd->m_p_prev_or_parent->m_p_l_child == p_nd)
93  {
94  if (p_new_child != 0)
95  {
96  p_new_child->m_p_prev_or_parent = p_nd->m_p_prev_or_parent;
97  p_new_child->m_p_next_sibling = p_nd->m_p_next_sibling;
98  if (p_new_child->m_p_next_sibling != 0)
99  p_new_child->m_p_next_sibling->m_p_prev_or_parent = p_new_child;
100  p_nd->m_p_prev_or_parent->m_p_l_child = p_new_child;
101  PB_DS_ASSERT_NODE_CONSISTENT(p_nd->m_p_prev_or_parent, false)
102  return;
103  }
104 
105  p_nd->m_p_prev_or_parent->m_p_l_child = p_nd->m_p_next_sibling;
106  if (p_nd->m_p_next_sibling != 0)
107  p_nd->m_p_next_sibling->m_p_prev_or_parent = p_nd->m_p_prev_or_parent;
108  PB_DS_ASSERT_NODE_CONSISTENT(p_nd->m_p_prev_or_parent, false)
109  return;
110  }
111 
112  if (p_new_child != 0)
113  {
114  p_new_child->m_p_prev_or_parent = p_nd->m_p_prev_or_parent;
115  p_new_child->m_p_next_sibling = p_nd->m_p_next_sibling;
116  if (p_new_child->m_p_next_sibling != 0)
117  p_new_child->m_p_next_sibling->m_p_prev_or_parent = p_new_child;
118  p_new_child->m_p_prev_or_parent->m_p_next_sibling = p_new_child;
119  PB_DS_ASSERT_NODE_CONSISTENT(p_nd->m_p_prev_or_parent, false)
120  return;
121  }
122 
123  p_nd->m_p_prev_or_parent->m_p_next_sibling = p_nd->m_p_next_sibling;
124  if (p_nd->m_p_next_sibling != 0)
125  p_nd->m_p_next_sibling->m_p_prev_or_parent = p_nd->m_p_prev_or_parent;
126  PB_DS_ASSERT_NODE_CONSISTENT(p_nd->m_p_prev_or_parent, false)
127 }
128 
129 PB_DS_CLASS_T_DEC
130 typename PB_DS_CLASS_C_DEC::node_pointer
131 PB_DS_CLASS_C_DEC::
132 join_node_children(node_pointer p_nd)
133 {
134  _GLIBCXX_DEBUG_ASSERT(p_nd != 0);
135  node_pointer p_ret = p_nd->m_p_l_child;
136  if (p_ret == 0)
137  return 0;
138  while (p_ret->m_p_next_sibling != 0)
139  p_ret = forward_join(p_ret, p_ret->m_p_next_sibling);
140  while (p_ret->m_p_prev_or_parent != p_nd)
141  p_ret = back_join(p_ret->m_p_prev_or_parent, p_ret);
142  PB_DS_ASSERT_NODE_CONSISTENT(p_ret, false)
143  return p_ret;
144 }
145 
146 PB_DS_CLASS_T_DEC
147 typename PB_DS_CLASS_C_DEC::node_pointer
148 PB_DS_CLASS_C_DEC::
149 forward_join(node_pointer p_nd, node_pointer p_next)
150 {
151  _GLIBCXX_DEBUG_ASSERT(p_nd != 0);
152  _GLIBCXX_DEBUG_ASSERT(p_nd->m_p_next_sibling == p_next);
153  if (Cmp_Fn::operator()(p_nd->m_value, p_next->m_value))
154  {
155  p_next->m_p_prev_or_parent = p_nd->m_p_prev_or_parent;
156  base_type::make_child_of(p_nd, p_next);
157  return p_next->m_p_next_sibling == 0
158  ? p_next : p_next->m_p_next_sibling;
159  }
160 
161  if (p_next->m_p_next_sibling != 0)
162  {
163  p_next->m_p_next_sibling->m_p_prev_or_parent = p_nd;
164  p_nd->m_p_next_sibling = p_next->m_p_next_sibling;
165  base_type::make_child_of(p_next, p_nd);
166  return p_nd->m_p_next_sibling;
167  }
168 
169  p_nd->m_p_next_sibling = 0;
170  base_type::make_child_of(p_next, p_nd);
171  PB_DS_ASSERT_NODE_CONSISTENT(p_nd, false)
172  return p_nd;
173 }
174 
175 PB_DS_CLASS_T_DEC
176 typename PB_DS_CLASS_C_DEC::node_pointer
177 PB_DS_CLASS_C_DEC::
178 back_join(node_pointer p_nd, node_pointer p_next)
179 {
180  _GLIBCXX_DEBUG_ASSERT(p_nd != 0);
181  _GLIBCXX_DEBUG_ASSERT(p_next->m_p_next_sibling == 0);
182 
183  if (Cmp_Fn::operator()(p_nd->m_value, p_next->m_value))
184  {
185  p_next->m_p_prev_or_parent = p_nd->m_p_prev_or_parent;
186  base_type::make_child_of(p_nd, p_next);
187  PB_DS_ASSERT_NODE_CONSISTENT(p_next, false)
188  return p_next;
189  }
190 
191  p_nd->m_p_next_sibling = 0;
192  base_type::make_child_of(p_next, p_nd);
193  PB_DS_ASSERT_NODE_CONSISTENT(p_nd, false)
194  return p_nd;
195 }
196 
197 PB_DS_CLASS_T_DEC
198 template<typename Pred>
199 typename PB_DS_CLASS_C_DEC::size_type
200 PB_DS_CLASS_C_DEC::
201 erase_if(Pred pred)
202 {
203  PB_DS_ASSERT_VALID((*this))
204  if (base_type::empty())
205  {
206  PB_DS_ASSERT_VALID((*this))
207  return 0;
208  }
209  base_type::to_linked_list();
210  node_pointer p_out = base_type::prune(pred);
211  size_type ersd = 0;
212  while (p_out != 0)
213  {
214  ++ersd;
215  node_pointer p_next = p_out->m_p_next_sibling;
216  base_type::actual_erase_node(p_out);
217  p_out = p_next;
218  }
219 
220  node_pointer p_cur = base_type::m_p_root;
221  base_type::m_p_root = 0;
222  while (p_cur != 0)
223  {
224  node_pointer p_next = p_cur->m_p_next_sibling;
225  p_cur->m_p_l_child = p_cur->m_p_next_sibling = p_cur->m_p_prev_or_parent = 0;
226 
227  push_imp(p_cur);
228  p_cur = p_next;
229  }
230  PB_DS_ASSERT_VALID((*this))
231  return ersd;
232 }
233