libstdc++
ext/iterator
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1 // HP/SGI iterator extensions -*- C++ -*-
2 
3 // Copyright (C) 2001-2025 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) 1996-1998
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/iterator
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_ITERATOR
57 #define _EXT_ITERATOR 1
58 
59 #ifdef _GLIBCXX_SYSHDR
60 #pragma GCC system_header
61 #endif
62 
63 #include <bits/concept_check.h>
64 #include <iterator>
65 
66 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
67 {
68 _GLIBCXX_BEGIN_NAMESPACE_VERSION
69 
70  // There are two signatures for distance. In addition to the one
71  // taking two iterators and returning a result, there is another
72  // taking two iterators and a reference-to-result variable, and
73  // returning nothing. The latter seems to be an SGI extension.
74  // -- pedwards
75  template<typename _InputIterator, typename _Distance>
76  inline void
77  __distance(_InputIterator __first, _InputIterator __last,
78  _Distance& __n, std::input_iterator_tag)
79  {
80  // concept requirements
81  __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
82  while (__first != __last)
83  {
84  ++__first;
85  ++__n;
86  }
87  }
88 
89  template<typename _RandomAccessIterator, typename _Distance>
90  inline void
91  __distance(_RandomAccessIterator __first, _RandomAccessIterator __last,
92  _Distance& __n, std::random_access_iterator_tag)
93  {
94  // concept requirements
95  __glibcxx_function_requires(_RandomAccessIteratorConcept<
96  _RandomAccessIterator>)
97  __n += __last - __first;
98  }
99 
100  /**
101  * This is an SGI extension.
102  * @ingroup SGIextensions
103  * @doctodo
104  */
105  template<typename _InputIterator, typename _Distance>
106  inline void
107  distance(_InputIterator __first, _InputIterator __last,
108  _Distance& __n)
109  {
110  // concept requirements -- taken care of in __distance
111  __distance(__first, __last, __n, std::__iterator_category(__first));
112  }
113 
114 _GLIBCXX_END_NAMESPACE_VERSION
115 } // namespace
116 
117 #endif
118