gnu/dist/gcc4/libstdc++-v3/include/bits/stl_tempbuf.h

   1 // Temporary buffer implementation -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2004, 2005 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  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 /** @file stl_tempbuf.h
  57  *  This is an internal header file, included by other library headers.
  58  *  You should not attempt to use it directly.
  59  */
  60
  61 #ifndef _TEMPBUF_H
  62 #define _TEMPBUF_H 1
  63
  64 #include <memory>
  65
  66 namespace std
  67 {
  68   /**
  69    *  @if maint
  70    *  This class is used in two places: stl_algo.h and ext/memory,
  71    *  where it is wrapped as the temporary_buffer class.  See
  72    *  temporary_buffer docs for more notes.
  73    *  @endif
  74    */
  75   template<typename _ForwardIterator, typename _Tp>
  76     class _Temporary_buffer
  77     {
  78       // concept requirements
  79       __glibcxx_class_requires(_ForwardIterator, _ForwardIteratorConcept)
  80
  81         public:
  82       typedef _Tp         value_type;
  83       typedef value_type* pointer;
  84       typedef pointer     iterator;
  85       typedef ptrdiff_t   size_type;
  86
  87     protected:
  88       size_type  _M_original_len;
  89       size_type  _M_len;
  90       pointer    _M_buffer;
  91
  92       void
  93       _M_initialize_buffer(const _Tp&, __true_type) { }
  94
  95       void
  96       _M_initialize_buffer(const _Tp& val, __false_type)
  97       { std::uninitialized_fill_n(_M_buffer, _M_len, val); }
  98
  99     public:
 100       /// As per Table mumble.
 101       size_type
 102       size() const
 103       { return _M_len; }
 104
 105       /// Returns the size requested by the constructor; may be >size().
 106       size_type
 107       requested_size() const
 108       { return _M_original_len; }
 109
 110       /// As per Table mumble.
 111       iterator
 112       begin()
 113       { return _M_buffer; }
 114
 115       /// As per Table mumble.
 116       iterator
 117       end()
 118       { return _M_buffer + _M_len; }
 119
 120       /**
 121        * Constructs a temporary buffer of a size somewhere between
 122        * zero and the size of the given range.
 123        */
 124       _Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last);
 125
 126       ~_Temporary_buffer()
 127       {
 128         std::_Destroy(_M_buffer, _M_buffer + _M_len);
 129         std::return_temporary_buffer(_M_buffer);
 130       }
 131
 132     private:
 133       // Disable copy constructor and assignment operator.
 134       _Temporary_buffer(const _Temporary_buffer&);
 135
 136       void
 137       operator=(const _Temporary_buffer&);
 138     };
 139
 140
 141   template<typename _ForwardIterator, typename _Tp>
 142     _Temporary_buffer<_ForwardIterator, _Tp>::
 143     _Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last)
 144     : _M_original_len(std::distance(__first, __last)),
 145       _M_len(0), _M_buffer(0)
 146     {
 147       // Workaround for a __type_traits bug in the pre-7.3 compiler.
 148       typedef typename std::__is_scalar<_Tp>::__type _Trivial;
 149
 150       try
 151         {
 152           pair<pointer, size_type> __p(get_temporary_buffer<
 153                                        value_type>(_M_original_len));
 154           _M_buffer = __p.first;
 155           _M_len = __p.second;
 156           if (_M_len > 0)
 157             _M_initialize_buffer(*__first, _Trivial());
 158         }
 159       catch(...)
 160         {
 161           std::return_temporary_buffer(_M_buffer);
 162           _M_buffer = 0;
 163           _M_len = 0;
 164           __throw_exception_again;
 165         }
 166     }
 167 } // namespace std
 168
 169 #endif /* _TEMPBUF_H */
 170