libstdc++
ext/memory
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1 // Memory extensions -*- C++ -*-
2 
3 // Copyright (C) 2002-2025 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 /*
26  *
27  * Copyright (c) 1994
28  * Hewlett-Packard Company
29  *
30  * Permission to use, copy, modify, distribute and sell this software
31  * and its documentation for any purpose is hereby granted without fee,
32  * provided that the above copyright notice appear in all copies and
33  * that both that copyright notice and this permission notice appear
34  * in supporting documentation. Hewlett-Packard Company makes no
35  * representations about the suitability of this software for any
36  * purpose. It is provided "as is" without express or implied warranty.
37  *
38  *
39  * Copyright (c) 1996
40  * Silicon Graphics Computer Systems, Inc.
41  *
42  * Permission to use, copy, modify, distribute and sell this software
43  * and its documentation for any purpose is hereby granted without fee,
44  * provided that the above copyright notice appear in all copies and
45  * that both that copyright notice and this permission notice appear
46  * in supporting documentation. Silicon Graphics makes no
47  * representations about the suitability of this software for any
48  * purpose. It is provided "as is" without express or implied warranty.
49  */
50 
51 /** @file ext/memory
52  * This file is a GNU extension to the Standard C++ Library (possibly
53  * containing extensions from the HP/SGI STL subset).
54  */
55 
56 #ifndef _EXT_MEMORY
57 #define _EXT_MEMORY 1
58 
59 #ifdef _GLIBCXX_SYSHDR
60 #pragma GCC system_header
61 #endif
62 
63 #include <bits/requires_hosted.h> // GNU extensions are currently omitted
64 
65 #include <memory>
66 #include <bits/stl_tempbuf.h>
67 
68 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
69 {
70 _GLIBCXX_BEGIN_NAMESPACE_VERSION
71 
72  using std::_Temporary_buffer;
73 
74  template<typename _InputIter, typename _Size, typename _ForwardIter>
75  std::pair<_InputIter, _ForwardIter>
76  __uninitialized_copy_n(_InputIter __first, _Size __count,
77  _ForwardIter __result, std::input_iterator_tag)
78  {
79  _ForwardIter __cur = __result;
80  __try
81  {
82  for (; __count > 0 ; --__count, ++__first, ++__cur)
83  std::_Construct(&*__cur, *__first);
84  return std::pair<_InputIter, _ForwardIter>(__first, __cur);
85  }
86  __catch(...)
87  {
88  std::_Destroy(__result, __cur);
89  __throw_exception_again;
90  }
91  }
92 
93  template<typename _RandomAccessIter, typename _Size, typename _ForwardIter>
94  inline std::pair<_RandomAccessIter, _ForwardIter>
95  __uninitialized_copy_n(_RandomAccessIter __first, _Size __count,
96  _ForwardIter __result,
97  std::random_access_iterator_tag)
98  {
99  _RandomAccessIter __last = __first + __count;
100  return (std::pair<_RandomAccessIter, _ForwardIter>
101  (__last, std::uninitialized_copy(__first, __last, __result)));
102  }
103 
104  template<typename _InputIter, typename _Size, typename _ForwardIter>
105  inline std::pair<_InputIter, _ForwardIter>
106  __uninitialized_copy_n(_InputIter __first, _Size __count,
107  _ForwardIter __result)
108  {
109  return __gnu_cxx::__uninitialized_copy_n(__first, __count, __result,
110  std::__iterator_category(__first));
111  }
112 
113  /**
114  * @brief Copies the range [first,last) into result.
115  * @param __first An input iterator.
116  * @param __count Length
117  * @param __result An output iterator.
118  * @return __result + (__first + __count)
119  * @ingroup SGIextensions
120  *
121  * Like copy(), but does not require an initialized output range.
122  */
123  template<typename _InputIter, typename _Size, typename _ForwardIter>
124  inline std::pair<_InputIter, _ForwardIter>
125  uninitialized_copy_n(_InputIter __first, _Size __count,
126  _ForwardIter __result)
127  {
128  return __gnu_cxx::__uninitialized_copy_n(__first, __count, __result,
129  std::__iterator_category(__first));
130  }
131 
132 
133  // An alternative version of uninitialized_copy_n that constructs
134  // and destroys objects with a user-provided allocator.
135  template<typename _InputIter, typename _Size, typename _ForwardIter,
136  typename _Allocator>
137  std::pair<_InputIter, _ForwardIter>
138  __uninitialized_copy_n_a(_InputIter __first, _Size __count,
139  _ForwardIter __result,
140  _Allocator __alloc)
141  {
142  _ForwardIter __cur = __result;
143  __try
144  {
145  for (; __count > 0 ; --__count, ++__first, ++__cur)
146  __alloc.construct(&*__cur, *__first);
147  return std::pair<_InputIter, _ForwardIter>(__first, __cur);
148  }
149  __catch(...)
150  {
151  std::_Destroy(__result, __cur, __alloc);
152  __throw_exception_again;
153  }
154  }
155 
156  template<typename _InputIter, typename _Size, typename _ForwardIter,
157  typename _Tp>
158  inline std::pair<_InputIter, _ForwardIter>
159  __uninitialized_copy_n_a(_InputIter __first, _Size __count,
160  _ForwardIter __result,
161  std::allocator<_Tp>)
162  {
163  return __gnu_cxx::uninitialized_copy_n(__first, __count, __result);
164  }
165 
166  /**
167  * This class provides similar behavior and semantics of the standard
168  * functions get_temporary_buffer() and return_temporary_buffer(), but
169  * encapsulated in a type vaguely resembling a standard container.
170  *
171  * By default, a temporary_buffer<Iter> stores space for objects of
172  * whatever type the Iter iterator points to. It is constructed from a
173  * typical [first,last) range, and provides the begin(), end(), size()
174  * functions, as well as requested_size(). For non-trivial types, copies
175  * of *first will be used to initialize the storage.
176  *
177  * @c malloc is used to obtain underlying storage.
178  *
179  * Like get_temporary_buffer(), not all the requested memory may be
180  * available. Ideally, the created buffer will be large enough to hold a
181  * copy of [first,last), but if size() is less than requested_size(),
182  * then this didn't happen.
183  *
184  * @ingroup SGIextensions
185  */
186  template <class _ForwardIterator, class _Tp
187  = typename std::iterator_traits<_ForwardIterator>::value_type >
188  struct temporary_buffer : public _Temporary_buffer<_ForwardIterator, _Tp>
189  {
190  /// Requests storage large enough to hold a copy of [first,last).
191  temporary_buffer(_ForwardIterator __first, _ForwardIterator __last)
192  : _Temporary_buffer<_ForwardIterator, _Tp>(__first,
193  std::distance(__first, __last))
194  { }
195 
196  /// Destroys objects and frees storage.
197  ~temporary_buffer() { }
198  };
199 
200 _GLIBCXX_END_NAMESPACE_VERSION
201 } // namespace
202 
203 #endif
204