1// Temporary buffer implementation -*- C++ -*-
2
3// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
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 <memory>
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
173