libstdc++: memory Source File

libstdc++

ext/memory
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1// Memory extensions -*- C++ -*-
2
3// Copyright (C) 2002-2026 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
68namespace __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
requires_hosted.h
stl_tempbuf.h
__gnu_cxx::uninitialized_copy_n
std::pair< _InputIter, _ForwardIter > uninitialized_copy_n(_InputIter __first, _Size __count, _ForwardIter __result)
Copies the range [first,last) into result.
Definition ext/memory:125
__gnu_cxx::distance
void distance(_InputIterator __first, _InputIterator __last, _Distance &__n)
Definition ext/iterator:107
std::uninitialized_copy
constexpr _ForwardIterator uninitialized_copy(_InputIterator __first, _InputIterator __last, _ForwardIterator __result)
Copies the range [first,last) into result.
Definition stl_uninitialized.h:252
std::pair::pair
pair(_T1, _T2) -> pair< _T1, _T2 >
Two pairs are equal iff their members are equal.
std
ISO C++ entities toplevel namespace is std.
std::_Construct
constexpr void _Construct(_Tp *__p, _Args &&... __args)
Definition stl_construct.h:123
std::_Destroy
constexpr void _Destroy(_ForwardIterator __first, _ForwardIterator __last)
Definition stl_construct.h:219
__gnu_cxx
GNU extensions for public use.
std::pair
Struct holding two objects (or references) of arbitrary type.
Definition stl_pair.h:307
std::_Temporary_buffer::_Temporary_buffer
_Temporary_buffer(_ForwardIterator __seed, size_type __original_len)
Definition stl_tempbuf.h:322
__gnu_cxx::temporary_buffer::temporary_buffer
temporary_buffer(_ForwardIterator __first, _ForwardIterator __last)
Requests storage large enough to hold a copy of [first,last).
Definition ext/memory:191
__gnu_cxx::temporary_buffer::~temporary_buffer
~temporary_buffer()
Destroys objects and frees storage.
Definition ext/memory:197
memory