libstdc++-v3/src/c++98/list.cc

   1 // std::list utilities implementation -*- C++ -*-
   2
   3 // Copyright (C) 2003-2025 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
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  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.
  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 /*
  26  *
  27  * Copyright (c) 1994
  28  * Hewlett-Packard Company
  29  *
  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.  Hewlett-Packard Company makes no
  35  * representations about the suitability of this software for any
  36  * purpose.  It is provided "as is" without express or implied warranty.
  37  *
  38  *
  39  * Copyright (c) 1996,1997
  40  * Silicon Graphics Computer Systems, Inc.
  41  *
  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.  Silicon Graphics makes no
  47  * representations about the suitability of this software for any
  48  * purpose.  It is provided "as is" without express or implied warranty.
  49  */
  50
  51 #include <list>
  52
  53 namespace std _GLIBCXX_VISIBILITY(default)
  54 {
  55 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  56
  57   namespace __detail
  58   {
  59     void
  60     _List_node_base::swap(_List_node_base& __x,
  61                           _List_node_base& __y) _GLIBCXX_USE_NOEXCEPT
  62     {
  63       if ( __x._M_next != &__x )
  64         {
  65           if ( __y._M_next != &__y )
  66             {
  67               // Both __x and __y are not empty.
  68               std::swap(__x._M_next,__y._M_next);
  69               std::swap(__x._M_prev,__y._M_prev);
  70               __x._M_next->_M_prev = __x._M_prev->_M_next = &__x;
  71               __y._M_next->_M_prev = __y._M_prev->_M_next = &__y;
  72             }
  73           else
  74             {
  75               // __x is not empty, __y is empty.
  76               __y._M_next = __x._M_next;
  77               __y._M_prev = __x._M_prev;
  78               __y._M_next->_M_prev = __y._M_prev->_M_next = &__y;
  79               __x._M_next = __x._M_prev = &__x;
  80             }
  81         }
  82       else if ( __y._M_next != &__y )
  83         {
  84           // __x is empty, __y is not empty.
  85           __x._M_next = __y._M_next;
  86           __x._M_prev = __y._M_prev;
  87           __x._M_next->_M_prev = __x._M_prev->_M_next = &__x;
  88           __y._M_next = __y._M_prev = &__y;
  89         }
  90     }
  91
  92     void
  93     _List_node_base::
  94     _M_transfer(_List_node_base * const __first,
  95                 _List_node_base * const __last) _GLIBCXX_USE_NOEXCEPT
  96     {
  97       __glibcxx_assert(__first != __last);
  98
  99       if (this != __last)
 100         {
 101           // Remove [first, last) from its old position.
 102           __last->_M_prev->_M_next  = this;
 103           __first->_M_prev->_M_next = __last;
 104           this->_M_prev->_M_next    = __first;
 105
 106           // Splice [first, last) into its new position.
 107           _List_node_base* const __tmp = this->_M_prev;
 108           this->_M_prev                = __last->_M_prev;
 109           __last->_M_prev              = __first->_M_prev;
 110           __first->_M_prev             = __tmp;
 111         }
 112     }
 113
 114     void
 115     _List_node_base::_M_reverse() _GLIBCXX_USE_NOEXCEPT
 116     {
 117       _List_node_base* __tmp = this;
 118       do
 119         {
 120           std::swap(__tmp->_M_next, __tmp->_M_prev);
 121
 122           // Old next node is now prev.
 123           __tmp = __tmp->_M_prev;
 124         }
 125       while (__tmp != this);
 126     }
 127
 128     void
 129     _List_node_base::
 130     _M_hook(_List_node_base* const __position) _GLIBCXX_USE_NOEXCEPT
 131     {
 132       this->_M_next = __position;
 133       this->_M_prev = __position->_M_prev;
 134       __position->_M_prev->_M_next = this;
 135       __position->_M_prev = this;
 136     }
 137
 138     void
 139     _List_node_base::_M_unhook() _GLIBCXX_USE_NOEXCEPT
 140     {
 141       _List_node_base* const __next_node = this->_M_next;
 142       _List_node_base* const __prev_node = this->_M_prev;
 143       __prev_node->_M_next = __next_node;
 144       __next_node->_M_prev = __prev_node;
 145     }
 146   } // namespace __detail
 147
 148 _GLIBCXX_END_NAMESPACE_VERSION
 149 } // namespace std