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      1 // -*- C++ -*-
      2 
      3 // Copyright (C) 2005-2013 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 rb_tree_map_/erase_fn_imps.hpp
     38  * Contains an implementation for rb_tree_.
     39  */
     40 
     41 PB_DS_CLASS_T_DEC
     42 inline bool
     43 PB_DS_CLASS_C_DEC::
     44 erase(key_const_reference r_key)
     45 {
     46   point_iterator it = this->find(r_key);
     47   if (it == base_type::end())
     48     return false;
     49   erase(it);
     50   return true;
     51 }
     52 
     53 PB_DS_CLASS_T_DEC
     54 inline typename PB_DS_CLASS_C_DEC::iterator
     55 PB_DS_CLASS_C_DEC::
     56 erase(iterator it)
     57 {
     58   PB_DS_ASSERT_VALID((*this))
     59   if (it == base_type::end())
     60     return it;
     61 
     62   iterator ret_it = it;
     63   ++ret_it;
     64   erase_node(it.m_p_nd);
     65   PB_DS_ASSERT_VALID((*this))
     66   return ret_it;
     67 }
     68 
     69 PB_DS_CLASS_T_DEC
     70 inline typename PB_DS_CLASS_C_DEC::reverse_iterator
     71 PB_DS_CLASS_C_DEC::
     72 erase(reverse_iterator it)
     73 {
     74   PB_DS_ASSERT_VALID((*this))
     75   if (it.m_p_nd == base_type::m_p_head)
     76     return it;
     77 
     78   reverse_iterator ret_it = it;
     79   ++ret_it;
     80   erase_node(it.m_p_nd);
     81   PB_DS_ASSERT_VALID((*this))
     82   return ret_it;
     83 }
     84 
     85 PB_DS_CLASS_T_DEC
     86 template<typename Pred>
     87 inline typename PB_DS_CLASS_C_DEC::size_type
     88 PB_DS_CLASS_C_DEC::
     89 erase_if(Pred pred)
     90 {
     91   PB_DS_ASSERT_VALID((*this))
     92   size_type num_ersd = 0;
     93   iterator it = base_type::begin();
     94   while (it != base_type::end())
     95     {
     96       if (pred(*it))
     97         {
     98 	  ++num_ersd;
     99 	  it = erase(it);
    100         }
    101       else
    102 	++it;
    103     }
    104 
    105   PB_DS_ASSERT_VALID((*this))
    106   return num_ersd;
    107 }
    108 
    109 PB_DS_CLASS_T_DEC
    110 void
    111 PB_DS_CLASS_C_DEC::
    112 erase_node(node_pointer p_nd)
    113 {
    114   remove_node(p_nd);
    115   base_type::actual_erase_node(p_nd);
    116   PB_DS_ASSERT_VALID((*this))
    117 }
    118 
    119 PB_DS_CLASS_T_DEC
    120 void
    121 PB_DS_CLASS_C_DEC::
    122 remove_node(node_pointer p_z)
    123 {
    124   this->update_min_max_for_erased_node(p_z);
    125   node_pointer p_y = p_z;
    126   node_pointer p_x = 0;
    127   node_pointer p_new_x_parent = 0;
    128 
    129   if (p_y->m_p_left == 0)
    130     p_x = p_y->m_p_right;
    131   else if (p_y->m_p_right == 0)
    132     p_x = p_y->m_p_left;
    133   else
    134     {
    135       p_y = p_y->m_p_right;
    136       while (p_y->m_p_left != 0)
    137 	p_y = p_y->m_p_left;
    138       p_x = p_y->m_p_right;
    139     }
    140 
    141   if (p_y == p_z)
    142     {
    143       p_new_x_parent = p_y->m_p_parent;
    144       if (p_x != 0)
    145 	p_x->m_p_parent = p_y->m_p_parent;
    146 
    147       if (base_type::m_p_head->m_p_parent == p_z)
    148 	base_type::m_p_head->m_p_parent = p_x;
    149       else if (p_z->m_p_parent->m_p_left == p_z)
    150         {
    151 	  p_y->m_p_left = p_z->m_p_parent;
    152 	  p_z->m_p_parent->m_p_left = p_x;
    153         }
    154       else
    155         {
    156 	  p_y->m_p_left = 0;
    157 	  p_z->m_p_parent->m_p_right = p_x;
    158         }
    159     }
    160   else
    161     {
    162       p_z->m_p_left->m_p_parent = p_y;
    163       p_y->m_p_left = p_z->m_p_left;
    164       if (p_y != p_z->m_p_right)
    165         {
    166 	  p_new_x_parent = p_y->m_p_parent;
    167 	  if (p_x != 0)
    168 	    p_x->m_p_parent = p_y->m_p_parent;
    169 	  p_y->m_p_parent->m_p_left = p_x;
    170 	  p_y->m_p_right = p_z->m_p_right;
    171 	  p_z->m_p_right->m_p_parent = p_y;
    172         }
    173       else
    174 	p_new_x_parent = p_y;
    175 
    176       if (base_type::m_p_head->m_p_parent == p_z)
    177 	base_type::m_p_head->m_p_parent = p_y;
    178       else if (p_z->m_p_parent->m_p_left == p_z)
    179 	p_z->m_p_parent->m_p_left = p_y;
    180       else
    181 	p_z->m_p_parent->m_p_right = p_y;
    182 
    183       p_y->m_p_parent = p_z->m_p_parent;
    184       std::swap(p_y->m_red, p_z->m_red);
    185       p_y = p_z;
    186     }
    187 
    188   this->update_to_top(p_new_x_parent, (node_update* )this);
    189 
    190   if (p_y->m_red)
    191     return;
    192 
    193   remove_fixup(p_x, p_new_x_parent);
    194 }
    195 
    196 PB_DS_CLASS_T_DEC
    197 void
    198 PB_DS_CLASS_C_DEC::
    199 remove_fixup(node_pointer p_x, node_pointer p_new_x_parent)
    200 {
    201   _GLIBCXX_DEBUG_ASSERT(p_x == 0 || p_x->m_p_parent == p_new_x_parent);
    202 
    203   while (p_x != base_type::m_p_head->m_p_parent && is_effectively_black(p_x))
    204     if (p_x == p_new_x_parent->m_p_left)
    205       {
    206 	node_pointer p_w = p_new_x_parent->m_p_right;
    207 	if (p_w->m_red)
    208 	  {
    209 	    p_w->m_red = false;
    210 	    p_new_x_parent->m_red = true;
    211 	    base_type::rotate_left(p_new_x_parent);
    212 	    p_w = p_new_x_parent->m_p_right;
    213 	  }
    214 
    215 	if (is_effectively_black(p_w->m_p_left)
    216 	    && is_effectively_black(p_w->m_p_right))
    217 	  {
    218 	    p_w->m_red = true;
    219 	    p_x = p_new_x_parent;
    220 	    p_new_x_parent = p_new_x_parent->m_p_parent;
    221 	  }
    222 	else
    223 	  {
    224 	    if (is_effectively_black(p_w->m_p_right))
    225 	      {
    226 		if (p_w->m_p_left != 0)
    227 		  p_w->m_p_left->m_red = false;
    228 
    229 		p_w->m_red = true;
    230 		base_type::rotate_right(p_w);
    231 		p_w = p_new_x_parent->m_p_right;
    232 	      }
    233 
    234 	    p_w->m_red = p_new_x_parent->m_red;
    235 	    p_new_x_parent->m_red = false;
    236 
    237 	    if (p_w->m_p_right != 0)
    238 	      p_w->m_p_right->m_red = false;
    239 
    240 	    base_type::rotate_left(p_new_x_parent);
    241 	    this->update_to_top(p_new_x_parent, (node_update* )this);
    242 	    break;
    243 	  }
    244       }
    245     else
    246       {
    247 	node_pointer p_w = p_new_x_parent->m_p_left;
    248 	if (p_w->m_red == true)
    249 	  {
    250 	    p_w->m_red = false;
    251 	    p_new_x_parent->m_red = true;
    252 	    base_type::rotate_right(p_new_x_parent);
    253 	    p_w = p_new_x_parent->m_p_left;
    254 	  }
    255 
    256 	if (is_effectively_black(p_w->m_p_right)
    257 	    && is_effectively_black(p_w->m_p_left))
    258 	  {
    259 	    p_w->m_red = true;
    260 	    p_x = p_new_x_parent;
    261 	    p_new_x_parent = p_new_x_parent->m_p_parent;
    262 	  }
    263 	else
    264 	  {
    265 	    if (is_effectively_black(p_w->m_p_left))
    266 	      {
    267 		if (p_w->m_p_right != 0)
    268 		  p_w->m_p_right->m_red = false;
    269 
    270 		p_w->m_red = true;
    271 		base_type::rotate_left(p_w);
    272 		p_w = p_new_x_parent->m_p_left;
    273 	      }
    274 
    275 	    p_w->m_red = p_new_x_parent->m_red;
    276 	    p_new_x_parent->m_red = false;
    277 
    278 	    if (p_w->m_p_left != 0)
    279 	      p_w->m_p_left->m_red = false;
    280 
    281 	    base_type::rotate_right(p_new_x_parent);
    282 	    this->update_to_top(p_new_x_parent, (node_update* )this);
    283 	    break;
    284 	  }
    285       }
    286 
    287   if (p_x != 0)
    288     p_x->m_red = false;
    289 }
    290