experimental/iterator

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// <experimental/iterator> -*- C++ -*-
 
// Copyright (C) 2015-2025 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
 
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
 
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.
 
/** @file experimental/iterator
 *  This is a TS C++ Library header.
 *  @ingroup libfund-ts
 */
 
//
// N4336 Working Draft, C++ Extensions for Library Fundamentals, Version 2
//
 
#ifndef _GLIBCXX_EXPERIMENTAL_ITERATOR
#define _GLIBCXX_EXPERIMENTAL_ITERATOR 1
 
#ifdef _GLIBCXX_SYSHDR
#pragma GCC system_header
#endif
 
#include <bits/requires_hosted.h> // experimental is currently omitted
 
#if __cplusplus >= 201402L
 
#include <iterator>
#include <iosfwd>
#include <experimental/type_traits>
 
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
 
namespace experimental
{
inline namespace fundamentals_v2
{
#define __cpp_lib_experimental_ostream_joiner 201411
 
  /// Output iterator that inserts a delimiter between elements.
  template<typename _DelimT, typename _CharT = char,
           typename _Traits = char_traits<_CharT>>
  class ostream_joiner
  {
  public:
    typedef _CharT                              char_type;
    typedef _Traits                             traits_type;
    typedef basic_ostream<_CharT, _Traits>      ostream_type;
    typedef output_iterator_tag                 iterator_category;
    typedef void                                value_type;
    typedef void                                difference_type;
    typedef void                                pointer;
    typedef void                                reference;
 
    ostream_joiner(ostream_type& __os, const _DelimT& __delimiter)
    noexcept(is_nothrow_copy_constructible_v<_DelimT>)
    : _M_out(std::__addressof(__os)), _M_delim(__delimiter)
    { }
 
    ostream_joiner(ostream_type& __os, _DelimT&& __delimiter)
    noexcept(is_nothrow_move_constructible_v<_DelimT>)
    : _M_out(std::__addressof(__os)), _M_delim(std::move(__delimiter))
    { }
 
    template<typename _Tp>
      ostream_joiner&
      operator=(const _Tp& __value)
      {
        if (!_M_first)
          *_M_out << _M_delim;
        _M_first = false;
        *_M_out << __value;
        return *this;
      }
 
    ostream_joiner& operator*() noexcept { return *this; }
    ostream_joiner& operator++() noexcept { return *this; }
    ostream_joiner& operator++(int) noexcept { return *this; }
 
  private:
    ostream_type* _M_out;
    _DelimT _M_delim;
    bool _M_first = true;
  };
 
  /// Object generator for ostream_joiner.
  template<typename _CharT, typename _Traits, typename _DelimT>
    inline ostream_joiner<decay_t<_DelimT>, _CharT, _Traits>
    make_ostream_joiner(basic_ostream<_CharT, _Traits>& __os,
                        _DelimT&& __delimiter)
    { return { __os, std::forward<_DelimT>(__delimiter) }; }
} // namespace fundamentals_v2
} // namespace experimental
 
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
 
#endif // __cplusplus <= 201103L
 
#endif // _GLIBCXX_EXPERIMENTAL_ITERATOR