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      1 // <experimental/iterator> -*- C++ -*-
      2 
      3 // Copyright (C) 2015-2024 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 #pragma GCC system_header
     38 
     39 #include <bits/requires_hosted.h> // experimental is currently omitted
     40 
     41 #if __cplusplus >= 201402L
     42 
     43 #include <iterator>
     44 #include <iosfwd>
     45 #include <experimental/type_traits>
     46 
     47 namespace std _GLIBCXX_VISIBILITY(default)
     48 {
     49 _GLIBCXX_BEGIN_NAMESPACE_VERSION
     50 
     51 namespace experimental
     52 {
     53 inline namespace fundamentals_v2
     54 {
     55 #define __cpp_lib_experimental_ostream_joiner 201411
     56 
     57   /// Output iterator that inserts a delimiter between elements.
     58   template<typename _DelimT, typename _CharT = char,
     59 	   typename _Traits = char_traits<_CharT>>
     60   class ostream_joiner
     61   {
     62   public:
     63     typedef _CharT				char_type;
     64     typedef _Traits				traits_type;
     65     typedef basic_ostream<_CharT, _Traits>	ostream_type;
     66     typedef output_iterator_tag			iterator_category;
     67     typedef void				value_type;
     68     typedef void				difference_type;
     69     typedef void				pointer;
     70     typedef void				reference;
     71 
     72     ostream_joiner(ostream_type& __os, const _DelimT& __delimiter)
     73     noexcept(is_nothrow_copy_constructible_v<_DelimT>)
     74     : _M_out(std::__addressof(__os)), _M_delim(__delimiter)
     75     { }
     76 
     77     ostream_joiner(ostream_type& __os, _DelimT&& __delimiter)
     78     noexcept(is_nothrow_move_constructible_v<_DelimT>)
     79     : _M_out(std::__addressof(__os)), _M_delim(std::move(__delimiter))
     80     { }
     81 
     82     template<typename _Tp>
     83       ostream_joiner&
     84       operator=(const _Tp& __value)
     85       {
     86 	if (!_M_first)
     87 	  *_M_out << _M_delim;
     88 	_M_first = false;
     89 	*_M_out << __value;
     90 	return *this;
     91       }
     92 
     93     ostream_joiner& operator*() noexcept { return *this; }
     94     ostream_joiner& operator++() noexcept { return *this; }
     95     ostream_joiner& operator++(int) noexcept { return *this; }
     96 
     97   private:
     98     ostream_type* _M_out;
     99     _DelimT _M_delim;
    100     bool _M_first = true;
    101   };
    102 
    103   /// Object generator for ostream_joiner.
    104   template<typename _CharT, typename _Traits, typename _DelimT>
    105     inline ostream_joiner<decay_t<_DelimT>, _CharT, _Traits>
    106     make_ostream_joiner(basic_ostream<_CharT, _Traits>& __os,
    107 			_DelimT&& __delimiter)
    108     { return { __os, std::forward<_DelimT>(__delimiter) }; }
    109 } // namespace fundamentals_v2
    110 } // namespace experimental
    111 
    112 _GLIBCXX_END_NAMESPACE_VERSION
    113 } // namespace std
    114 
    115 #endif // __cplusplus <= 201103L
    116 
    117 #endif // _GLIBCXX_EXPERIMENTAL_ITERATOR
    118