libstdc++-v3/src/list.cc

   1 // std::list utilities implementation -*- C++ -*-
   2
   3 // Copyright (C) 2003 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 2, 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 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 /*
  31  *
  32  * Copyright (c) 1994
  33  * Hewlett-Packard Company
  34  *
  35  * Permission to use, copy, modify, distribute and sell this software
  36  * and its documentation for any purpose is hereby granted without fee,
  37  * provided that the above copyright notice appear in all copies and
  38  * that both that copyright notice and this permission notice appear
  39  * in supporting documentation.  Hewlett-Packard Company makes no
  40  * representations about the suitability of this software for any
  41  * purpose.  It is provided "as is" without express or implied warranty.
  42  *
  43  *
  44  * Copyright (c) 1996,1997
  45  * Silicon Graphics Computer Systems, Inc.
  46  *
  47  * Permission to use, copy, modify, distribute and sell this software
  48  * and its documentation for any purpose is hereby granted without fee,
  49  * provided that the above copyright notice appear in all copies and
  50  * that both that copyright notice and this permission notice appear
  51  * in supporting documentation.  Silicon Graphics makes no
  52  * representations about the suitability of this software for any
  53  * purpose.  It is provided "as is" without express or implied warranty.
  54  */
  55
  56 #include <list>
  57
  58 namespace _GLIBCXX_STD
  59 {
  60   void
  61   _List_node_base::swap(_List_node_base& __x, _List_node_base& __y)
  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::transfer(_List_node_base * const __first,
  94                             _List_node_base * const __last)
  95   {
  96     if (this != __last)
  97     {
  98       // Remove [first, last) from its old position.
  99       __last->_M_prev->_M_next  = this;
 100       __first->_M_prev->_M_next = __last;
 101       this->_M_prev->_M_next    = __first;
 102
 103       // Splice [first, last) into its new position.
 104       _List_node_base* const __tmp = this->_M_prev;
 105       this->_M_prev                = __last->_M_prev;
 106       __last->_M_prev              = __first->_M_prev;
 107       __first->_M_prev             = __tmp;
 108     }
 109   }
 110
 111   void
 112   _List_node_base::reverse()
 113   {
 114     _List_node_base* __tmp = this;
 115     do
 116     {
 117       std::swap(__tmp->_M_next, __tmp->_M_prev);
 118       __tmp = __tmp->_M_prev;     // Old next node is now prev.
 119     }
 120     while (__tmp != this);
 121   }
 122
 123   void
 124   _List_node_base::hook(_List_node_base* const __position)
 125   {
 126     this->_M_next = __position;
 127     this->_M_prev = __position->_M_prev;
 128     __position->_M_prev->_M_next = this;
 129     __position->_M_prev = this;
 130   }
 131
 132   void
 133   _List_node_base::unhook()
 134   {
 135     _List_node_base* const __next_node = this->_M_next;
 136     _List_node_base* const __prev_node = this->_M_prev;
 137     __prev_node->_M_next = __next_node;
 138     __next_node->_M_prev = __prev_node;
 139   }
 140 } // namespace std
 141