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

   1 // Compatibility symbols for previous versions, list bits -*- C++ -*-
   2
   3 // Copyright (C) 2010-2024 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 #include <bits/move.h>
  26
  27 #ifndef _GLIBCXX_BEGIN_NAMESPACE_COMPAT
  28 # define _GLIBCXX_BEGIN_NAMESPACE_COMPAT
  29 #endif
  30
  31 #ifndef _GLIBCXX_END_NAMESPACE_COMPAT
  32 # define _GLIBCXX_END_NAMESPACE_COMPAT
  33 #endif
  34
  35 namespace std _GLIBCXX_VISIBILITY(default)
  36 {
  37 _GLIBCXX_BEGIN_NAMESPACE_COMPAT
  38
  39   struct _List_node_base
  40   {
  41     _List_node_base* _M_next;
  42     _List_node_base* _M_prev;
  43
  44     static void
  45     swap(_List_node_base& __x, _List_node_base& __y) throw ();
  46
  47     void
  48     transfer(_List_node_base * const __first,
  49              _List_node_base * const __last) throw ();
  50
  51     void
  52     reverse() throw ();
  53
  54     void
  55     hook(_List_node_base * const __position) throw ();
  56
  57     void
  58     unhook() throw ();
  59   };
  60
  61   void
  62   _List_node_base::swap(_List_node_base& __x, _List_node_base& __y) throw()
  63   {
  64     if ( __x._M_next != &__x )
  65       {
  66         if ( __y._M_next != &__y )
  67           {
  68             // Both __x and __y are not empty.
  69             std::swap(__x._M_next,__y._M_next);
  70             std::swap(__x._M_prev,__y._M_prev);
  71             __x._M_next->_M_prev = __x._M_prev->_M_next = &__x;
  72             __y._M_next->_M_prev = __y._M_prev->_M_next = &__y;
  73           }
  74         else
  75           {
  76             // __x is not empty, __y is empty.
  77             __y._M_next = __x._M_next;
  78             __y._M_prev = __x._M_prev;
  79             __y._M_next->_M_prev = __y._M_prev->_M_next = &__y;
  80             __x._M_next = __x._M_prev = &__x;
  81           }
  82       }
  83     else if ( __y._M_next != &__y )
  84       {
  85         // __x is empty, __y is not empty.
  86         __x._M_next = __y._M_next;
  87         __x._M_prev = __y._M_prev;
  88         __x._M_next->_M_prev = __x._M_prev->_M_next = &__x;
  89         __y._M_next = __y._M_prev = &__y;
  90       }
  91   }
  92
  93   void
  94   _List_node_base::transfer(_List_node_base * const __first,
  95                             _List_node_base * const __last) throw ()
  96   {
  97     if (this != __last)
  98     {
  99       // Remove [first, last) from its old position.
 100       __last->_M_prev->_M_next  = this;
 101       __first->_M_prev->_M_next = __last;
 102       this->_M_prev->_M_next    = __first;
 103
 104       // Splice [first, last) into its new position.
 105       _List_node_base* const __tmp = this->_M_prev;
 106       this->_M_prev                = __last->_M_prev;
 107       __last->_M_prev              = __first->_M_prev;
 108       __first->_M_prev             = __tmp;
 109     }
 110   }
 111
 112   void
 113   _List_node_base::reverse() throw ()
 114   {
 115     _List_node_base* __tmp = this;
 116     do
 117     {
 118       std::swap(__tmp->_M_next, __tmp->_M_prev);
 119
 120       // Old next node is now prev.
 121       __tmp = __tmp->_M_prev;
 122     }
 123     while (__tmp != this);
 124   }
 125
 126   void
 127   _List_node_base::hook(_List_node_base* const __position) throw ()
 128   {
 129     this->_M_next = __position;
 130     this->_M_prev = __position->_M_prev;
 131     __position->_M_prev->_M_next = this;
 132     __position->_M_prev = this;
 133   }
 134
 135   void
 136   _List_node_base::unhook() throw ()
 137   {
 138     _List_node_base* const __next_node = this->_M_next;
 139     _List_node_base* const __prev_node = this->_M_prev;
 140     __prev_node->_M_next = __next_node;
 141     __next_node->_M_prev = __prev_node;
 142   }
 143
 144 _GLIBCXX_END_NAMESPACE_COMPAT
 145
 146 } // namespace std