libstdc++
experimental/iterator
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1 // <experimental/iterator> -*- C++ -*-
2 
3 // Copyright (C) 2015-2025 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 /** @file experimental/iterator
26  * This is a TS C++ Library header.
27  * @ingroup libfund-ts
28  */
29 
30 //
31 // N4336 Working Draft, C++ Extensions for Library Fundamentals, Version 2
32 //
33 
34 #ifndef _GLIBCXX_EXPERIMENTAL_ITERATOR
35 #define _GLIBCXX_EXPERIMENTAL_ITERATOR 1
36 
37 #ifdef _GLIBCXX_SYSHDR
38 #pragma GCC system_header
39 #endif
40 
41 #include <bits/requires_hosted.h> // experimental is currently omitted
42 
43 #if __cplusplus >= 201402L
44 
45 #include <iterator>
46 #include <iosfwd>
47 #include <experimental/type_traits>
48 
49 namespace std _GLIBCXX_VISIBILITY(default)
50 {
51 _GLIBCXX_BEGIN_NAMESPACE_VERSION
52 
53 namespace experimental
54 {
55 inline namespace fundamentals_v2
56 {
57 #define __cpp_lib_experimental_ostream_joiner 201411
58 
59  /// Output iterator that inserts a delimiter between elements.
60  template<typename _DelimT, typename _CharT = char,
61  typename _Traits = char_traits<_CharT>>
62  class ostream_joiner
63  {
64  public:
65  typedef _CharT char_type;
66  typedef _Traits traits_type;
67  typedef basic_ostream<_CharT, _Traits> ostream_type;
68  typedef output_iterator_tag iterator_category;
69  typedef void value_type;
70  typedef void difference_type;
71  typedef void pointer;
72  typedef void reference;
73 
74  ostream_joiner(ostream_type& __os, const _DelimT& __delimiter)
75  noexcept(is_nothrow_copy_constructible_v<_DelimT>)
76  : _M_out(std::__addressof(__os)), _M_delim(__delimiter)
77  { }
78 
79  ostream_joiner(ostream_type& __os, _DelimT&& __delimiter)
80  noexcept(is_nothrow_move_constructible_v<_DelimT>)
81  : _M_out(std::__addressof(__os)), _M_delim(std::move(__delimiter))
82  { }
83 
84  template<typename _Tp>
85  ostream_joiner&
86  operator=(const _Tp& __value)
87  {
88  if (!_M_first)
89  *_M_out << _M_delim;
90  _M_first = false;
91  *_M_out << __value;
92  return *this;
93  }
94 
95  ostream_joiner& operator*() noexcept { return *this; }
96  ostream_joiner& operator++() noexcept { return *this; }
97  ostream_joiner& operator++(int) noexcept { return *this; }
98 
99  private:
100  ostream_type* _M_out;
101  _DelimT _M_delim;
102  bool _M_first = true;
103  };
104 
105  /// Object generator for ostream_joiner.
106  template<typename _CharT, typename _Traits, typename _DelimT>
107  inline ostream_joiner<decay_t<_DelimT>, _CharT, _Traits>
108  make_ostream_joiner(basic_ostream<_CharT, _Traits>& __os,
109  _DelimT&& __delimiter)
110  { return { __os, std::forward<_DelimT>(__delimiter) }; }
111 } // namespace fundamentals_v2
112 } // namespace experimental
113 
114 _GLIBCXX_END_NAMESPACE_VERSION
115 } // namespace std
116 
117 #endif // __cplusplus <= 201103L
118 
119 #endif // _GLIBCXX_EXPERIMENTAL_ITERATOR