libstdc++-v3/include/bits/stl_tempbuf.h

   1 // Temporary buffer implementation -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 2, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING.  If not, write to the Free
  19 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  20 // USA.
  21
  22 // As a special exception, you may use this file as part of a free software
  23 // library without restriction.  Specifically, if other files instantiate
  24 // templates or use macros or inline functions from this file, or you compile
  25 // this file and link it with other files to produce an executable, this
  26 // file does not by itself cause the resulting executable to be covered by
  27 // the GNU General Public License.  This exception does not however
  28 // invalidate any other reasons why the executable file might be covered by
  29 // the GNU General Public License.
  30
  31 /*
  32  *
  33  * Copyright (c) 1994
  34  * Hewlett-Packard Company
  35  *
  36  * Permission to use, copy, modify, distribute and sell this software
  37  * and its documentation for any purpose is hereby granted without fee,
  38  * provided that the above copyright notice appear in all copies and
  39  * that both that copyright notice and this permission notice appear
  40  * in supporting documentation.  Hewlett-Packard Company makes no
  41  * representations about the suitability of this software for any
  42  * purpose.  It is provided "as is" without express or implied warranty.
  43  *
  44  *
  45  * Copyright (c) 1996,1997
  46  * Silicon Graphics Computer Systems, Inc.
  47  *
  48  * Permission to use, copy, modify, distribute and sell this software
  49  * and its documentation for any purpose is hereby granted without fee,
  50  * provided that the above copyright notice appear in all copies and
  51  * that both that copyright notice and this permission notice appear
  52  * in supporting documentation.  Silicon Graphics makes no
  53  * representations about the suitability of this software for any
  54  * purpose.  It is provided "as is" without express or implied warranty.
  55  */
  56
  57 /** @file stl_tempbuf.h
  58  *  This is an internal header file, included by other library headers.
  59  *  You should not attempt to use it directly.
  60  */
  61
  62 #ifndef _TEMPBUF_H
  63 #define _TEMPBUF_H 1
  64
  65 #include <bits/stl_memory.h>
  66
  67 _GLIBCXX_BEGIN_NAMESPACE(std)
  68
  69   /**
  70    *  @if maint
  71    *  This class is used in two places: stl_algo.h and ext/memory,
  72    *  where it is wrapped as the temporary_buffer class.  See
  73    *  temporary_buffer docs for more notes.
  74    *  @endif
  75    */
  76   template<typename _ForwardIterator, typename _Tp>
  77     class _Temporary_buffer
  78     {
  79       // concept requirements
  80       __glibcxx_class_requires(_ForwardIterator, _ForwardIteratorConcept)
  81
  82     public:
  83       typedef _Tp         value_type;
  84       typedef value_type* pointer;
  85       typedef pointer     iterator;
  86       typedef ptrdiff_t   size_type;
  87
  88     protected:
  89       size_type  _M_original_len;
  90       size_type  _M_len;
  91       pointer    _M_buffer;
  92
  93       void
  94       _M_initialize_buffer(const _Tp&, __true_type) { }
  95
  96       void
  97       _M_initialize_buffer(const _Tp& __val, __false_type)
  98       { std::uninitialized_fill_n(_M_buffer, _M_len, __val); }
  99
 100     public:
 101       /// As per Table mumble.
 102       size_type
 103       size() const
 104       { return _M_len; }
 105
 106       /// Returns the size requested by the constructor; may be >size().
 107       size_type
 108       requested_size() const
 109       { return _M_original_len; }
 110
 111       /// As per Table mumble.
 112       iterator
 113       begin()
 114       { return _M_buffer; }
 115
 116       /// As per Table mumble.
 117       iterator
 118       end()
 119       { return _M_buffer + _M_len; }
 120
 121       /**
 122        * Constructs a temporary buffer of a size somewhere between
 123        * zero and the size of the given range.
 124        */
 125       _Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last);
 126
 127       ~_Temporary_buffer()
 128       {
 129         std::_Destroy(_M_buffer, _M_buffer + _M_len);
 130         std::return_temporary_buffer(_M_buffer);
 131       }
 132
 133     private:
 134       // Disable copy constructor and assignment operator.
 135       _Temporary_buffer(const _Temporary_buffer&);
 136
 137       void
 138       operator=(const _Temporary_buffer&);
 139     };
 140
 141
 142   template<typename _ForwardIterator, typename _Tp>
 143     _Temporary_buffer<_ForwardIterator, _Tp>::
 144     _Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last)
 145     : _M_original_len(std::distance(__first, __last)),
 146       _M_len(0), _M_buffer(0)
 147     {
 148       // Workaround for a __type_traits bug in the pre-7.3 compiler.
 149       typedef typename std::__is_scalar<_Tp>::__type _Trivial;
 150
 151       try
 152         {
 153           pair<pointer, size_type> __p(get_temporary_buffer<
 154                                        value_type>(_M_original_len));
 155           _M_buffer = __p.first;
 156           _M_len = __p.second;
 157           if (_M_len > 0)
 158             _M_initialize_buffer(*__first, _Trivial());
 159         }
 160       catch(...)
 161         {
 162           std::return_temporary_buffer(_M_buffer);
 163           _M_buffer = 0;
 164           _M_len = 0;
 165           __throw_exception_again;
 166         }
 167     }
 168
 169 _GLIBCXX_END_NAMESPACE
 170
 171 #endif /* _TEMPBUF_H */
 172