libstdc++-v3/include/bits/stream_iterator.h - gcc - Git at Google

 // Stream iterators

 // Copyright (C) 2001-2021 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 bits/stream_iterator.h
  *  This is an internal header file, included by other library headers.
  *  Do not attempt to use it directly. @headername{iterator}
  */

 #ifndef _STREAM_ITERATOR_H
 #define _STREAM_ITERATOR_H 1

 #pragma GCC system_header

 #include <debug/debug.h>

 namespace std _GLIBCXX_VISIBILITY(default)
 {
 _GLIBCXX_BEGIN_NAMESPACE_VERSION

   /**
    * @addtogroup iterators
    * @{
    */

   /// Provides input iterator semantics for streams.
   template<typename _Tp, typename _CharT = char,
            typename _Traits = char_traits<_CharT>, typename _Dist = ptrdiff_t>
     class istream_iterator
     : public iterator<input_iterator_tag, _Tp, _Dist, const _Tp*, const _Tp&>
     {
     public:
       typedef _CharT                         char_type;
       typedef _Traits                        traits_type;
       typedef basic_istream<_CharT, _Traits> istream_type;

     private:
       istream_type*	_M_stream;
       _Tp		_M_value;
       // This bool becomes false at end-of-stream. It should be sufficient to
       // check _M_stream != nullptr instead, but historically we did not set
       // _M_stream to null when reaching the end, so we need to keep this flag.
       bool		_M_ok;

     public:
       ///  Construct end of input stream iterator.
       _GLIBCXX_CONSTEXPR istream_iterator()
       _GLIBCXX_NOEXCEPT_IF(is_nothrow_default_constructible<_Tp>::value)
       : _M_stream(0), _M_value(), _M_ok(false) {}

       ///  Construct start of input stream iterator.
       istream_iterator(istream_type& __s)
       : _M_stream(std::__addressof(__s)), _M_ok(true)
       { _M_read(); }

       istream_iterator(const istream_iterator& __obj)
       _GLIBCXX_NOEXCEPT_IF(is_nothrow_copy_constructible<_Tp>::value)
       : _M_stream(__obj._M_stream), _M_value(__obj._M_value),
         _M_ok(__obj._M_ok)
       { }

 #if __cplusplus > 201703L && __cpp_lib_concepts
       constexpr
       istream_iterator(default_sentinel_t)
       noexcept(is_nothrow_default_constructible_v<_Tp>)
       : istream_iterator() { }
 #endif

 #if __cplusplus >= 201103L
       istream_iterator& operator=(const istream_iterator&) = default;
       ~istream_iterator() = default;
 #endif

       _GLIBCXX_NODISCARD
       const _Tp&
       operator*() const _GLIBCXX_NOEXCEPT
       {
 	__glibcxx_requires_cond(_M_ok,
 				_M_message(__gnu_debug::__msg_deref_istream)
 				._M_iterator(*this));
 	return _M_value;
       }

       _GLIBCXX_NODISCARD
       const _Tp*
       operator->() const _GLIBCXX_NOEXCEPT
       { return std::__addressof((operator*())); }

       istream_iterator&
       operator++()
       {
 	__glibcxx_requires_cond(_M_ok,
 				_M_message(__gnu_debug::__msg_inc_istream)
 				._M_iterator(*this));
 	_M_read();
 	return *this;
       }

       istream_iterator
       operator++(int)
       {
 	__glibcxx_requires_cond(_M_ok,
 				_M_message(__gnu_debug::__msg_inc_istream)
 				._M_iterator(*this));
 	istream_iterator __tmp = *this;
 	_M_read();
 	return __tmp;
       }

     private:
       bool
       _M_equal(const istream_iterator& __x) const _GLIBCXX_NOEXCEPT
       {
 	// Ideally this would just return _M_stream == __x._M_stream,
 	// but code compiled with old versions never sets _M_stream to null.
 	return (_M_ok == __x._M_ok) && (!_M_ok || _M_stream == __x._M_stream);
       }

       void
       _M_read()
       {
         if (_M_stream && !(*_M_stream >> _M_value))
           {
             _M_stream = 0;
             _M_ok = false;
           }
       }

       /// Return true if the iterators refer to the same stream,
       /// or are both at end-of-stream.
       _GLIBCXX_NODISCARD
       friend bool
       operator==(const istream_iterator& __x, const istream_iterator& __y)
       _GLIBCXX_NOEXCEPT
       { return __x._M_equal(__y); }

 #if __cpp_impl_three_way_comparison < 201907L
       /// Return true if the iterators refer to different streams,
       /// or if one is at end-of-stream and the other is not.
       _GLIBCXX_NODISCARD
       friend bool
       operator!=(const istream_iterator& __x, const istream_iterator& __y)
       _GLIBCXX_NOEXCEPT
       { return !__x._M_equal(__y); }
 #endif

 #if __cplusplus > 201703L && __cpp_lib_concepts
       [[nodiscard]]
       friend bool
       operator==(const istream_iterator& __i, default_sentinel_t) noexcept
       { return !__i._M_stream; }
 #endif
     };

   /**
    *  @brief  Provides output iterator semantics for streams.
    *
    *  This class provides an iterator to write to an ostream.  The type Tp is
    *  the only type written by this iterator and there must be an
    *  operator<<(Tp) defined.
    *
    *  @tparam  _Tp  The type to write to the ostream.
    *  @tparam  _CharT  The ostream char_type.
    *  @tparam  _Traits  The ostream char_traits.
   */
   template<typename _Tp, typename _CharT = char,
            typename _Traits = char_traits<_CharT> >
     class ostream_iterator
     : public iterator<output_iterator_tag, void, void, void, void>
     {
     public:
       ///@{
       /// Public typedef
 #if __cplusplus > 201703L
       using difference_type = ptrdiff_t;
 #endif
       typedef _CharT                         char_type;
       typedef _Traits                        traits_type;
       typedef basic_ostream<_CharT, _Traits> ostream_type;
       ///@}

     private:
       ostream_type*	_M_stream;
       const _CharT*	_M_string;

     public:
       /// Construct from an ostream.
       ostream_iterator(ostream_type& __s) _GLIBCXX_NOEXCEPT
       : _M_stream(std::__addressof(__s)), _M_string(0) {}

       /**
        *  Construct from an ostream.
        *
        *  The delimiter string @a c is written to the stream after every Tp
        *  written to the stream.  The delimiter is not copied, and thus must
        *  not be destroyed while this iterator is in use.
        *
        *  @param  __s  Underlying ostream to write to.
        *  @param  __c  CharT delimiter string to insert.
       */
       ostream_iterator(ostream_type& __s, const _CharT* __c) _GLIBCXX_NOEXCEPT
       : _M_stream(std::__addressof(__s)), _M_string(__c)  { }

       /// Copy constructor.
       ostream_iterator(const ostream_iterator& __obj) _GLIBCXX_NOEXCEPT
       : _M_stream(__obj._M_stream), _M_string(__obj._M_string)  { }

 #if __cplusplus >= 201103L
       ostream_iterator& operator=(const ostream_iterator&) = default;
 #endif

       /// Writes @a value to underlying ostream using operator<<.  If
       /// constructed with delimiter string, writes delimiter to ostream.
       ostream_iterator&
       operator=(const _Tp& __value)
       {
 	__glibcxx_requires_cond(_M_stream != 0,
 				_M_message(__gnu_debug::__msg_output_ostream)
 				._M_iterator(*this));
 	*_M_stream << __value;
 	if (_M_string)
           *_M_stream << _M_string;
 	return *this;
       }

       _GLIBCXX_NODISCARD
       ostream_iterator&
       operator*() _GLIBCXX_NOEXCEPT
       { return *this; }

       ostream_iterator&
       operator++() _GLIBCXX_NOEXCEPT
       { return *this; }

       ostream_iterator&
       operator++(int) _GLIBCXX_NOEXCEPT
       { return *this; }
     };

   /// @} group iterators

 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace

 #endif
	// Stream iterators

	// Copyright (C) 2001-2021 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 bits/stream_iterator.h
	* This is an internal header file, included by other library headers.
	* Do not attempt to use it directly. @headername{iterator}
	*/

	#ifndef _STREAM_ITERATOR_H
	#define _STREAM_ITERATOR_H 1

	#pragma GCC system_header

	#include <debug/debug.h>

	namespace std _GLIBCXX_VISIBILITY(default)
	{
	_GLIBCXX_BEGIN_NAMESPACE_VERSION

	/**
	* @addtogroup iterators
	* @{
	*/

	/// Provides input iterator semantics for streams.
	template<typename _Tp, typename _CharT = char,
	typename _Traits = char_traits<_CharT>, typename _Dist = ptrdiff_t>
	class istream_iterator
	: public iterator<input_iterator_tag, _Tp, _Dist, const _Tp*, const _Tp&>
	{
	public:
	typedef _CharT char_type;
	typedef _Traits traits_type;
	typedef basic_istream<_CharT, _Traits> istream_type;

	private:
	istream_type* _M_stream;
	_Tp _M_value;
	// This bool becomes false at end-of-stream. It should be sufficient to
	// check _M_stream != nullptr instead, but historically we did not set
	// _M_stream to null when reaching the end, so we need to keep this flag.
	bool _M_ok;

	public:
	/// Construct end of input stream iterator.
	_GLIBCXX_CONSTEXPR istream_iterator()
	_GLIBCXX_NOEXCEPT_IF(is_nothrow_default_constructible<_Tp>::value)
	: _M_stream(0), _M_value(), _M_ok(false) {}

	/// Construct start of input stream iterator.
	istream_iterator(istream_type& __s)
	: _M_stream(std::__addressof(__s)), _M_ok(true)
	{ _M_read(); }

	istream_iterator(const istream_iterator& __obj)
	_GLIBCXX_NOEXCEPT_IF(is_nothrow_copy_constructible<_Tp>::value)
	: _M_stream(__obj._M_stream), _M_value(__obj._M_value),
	_M_ok(__obj._M_ok)
	{ }

	#if __cplusplus > 201703L && __cpp_lib_concepts
	constexpr
	istream_iterator(default_sentinel_t)
	noexcept(is_nothrow_default_constructible_v<_Tp>)
	: istream_iterator() { }
	#endif

	#if __cplusplus >= 201103L
	istream_iterator& operator=(const istream_iterator&) = default;
	~istream_iterator() = default;
	#endif

	_GLIBCXX_NODISCARD
	const _Tp&
	operator*() const _GLIBCXX_NOEXCEPT
	{
	__glibcxx_requires_cond(_M_ok,
	_M_message(__gnu_debug::__msg_deref_istream)
	._M_iterator(*this));
	return _M_value;
	}

	_GLIBCXX_NODISCARD
	const _Tp*
	operator->() const _GLIBCXX_NOEXCEPT
	{ return std::__addressof((operator*())); }

	istream_iterator&
	operator++()
	{
	__glibcxx_requires_cond(_M_ok,
	_M_message(__gnu_debug::__msg_inc_istream)
	._M_iterator(*this));
	_M_read();
	return *this;
	}

	istream_iterator
	operator++(int)
	{
	__glibcxx_requires_cond(_M_ok,
	_M_message(__gnu_debug::__msg_inc_istream)
	._M_iterator(*this));
	istream_iterator __tmp = *this;
	_M_read();
	return __tmp;
	}

	private:
	bool
	_M_equal(const istream_iterator& __x) const _GLIBCXX_NOEXCEPT
	{
	// Ideally this would just return _M_stream == __x._M_stream,
	// but code compiled with old versions never sets _M_stream to null.
	return (_M_ok == __x._M_ok) && (!_M_ok \|\| _M_stream == __x._M_stream);
	}

	void
	_M_read()
	{
	if (_M_stream && !(*_M_stream >> _M_value))
	{
	_M_stream = 0;
	_M_ok = false;
	}
	}

	/// Return true if the iterators refer to the same stream,
	/// or are both at end-of-stream.
	_GLIBCXX_NODISCARD
	friend bool
	operator==(const istream_iterator& __x, const istream_iterator& __y)
	_GLIBCXX_NOEXCEPT
	{ return __x._M_equal(__y); }

	#if __cpp_impl_three_way_comparison < 201907L
	/// Return true if the iterators refer to different streams,
	/// or if one is at end-of-stream and the other is not.
	_GLIBCXX_NODISCARD
	friend bool
	operator!=(const istream_iterator& __x, const istream_iterator& __y)
	_GLIBCXX_NOEXCEPT
	{ return !__x._M_equal(__y); }
	#endif

	#if __cplusplus > 201703L && __cpp_lib_concepts
	[[nodiscard]]
	friend bool
	operator==(const istream_iterator& __i, default_sentinel_t) noexcept
	{ return !__i._M_stream; }
	#endif
	};

	/**
	* @brief Provides output iterator semantics for streams.
	*
	* This class provides an iterator to write to an ostream. The type Tp is
	* the only type written by this iterator and there must be an
	* operator<<(Tp) defined.
	*
	* @tparam _Tp The type to write to the ostream.
	* @tparam _CharT The ostream char_type.
	* @tparam _Traits The ostream char_traits.
	*/
	template<typename _Tp, typename _CharT = char,
	typename _Traits = char_traits<_CharT> >
	class ostream_iterator
	: public iterator<output_iterator_tag, void, void, void, void>
	{
	public:
	///@{
	/// Public typedef
	#if __cplusplus > 201703L
	using difference_type = ptrdiff_t;
	#endif
	typedef _CharT char_type;
	typedef _Traits traits_type;
	typedef basic_ostream<_CharT, _Traits> ostream_type;
	///@}

	private:
	ostream_type* _M_stream;
	const _CharT* _M_string;

	public:
	/// Construct from an ostream.
	ostream_iterator(ostream_type& __s) _GLIBCXX_NOEXCEPT
	: _M_stream(std::__addressof(__s)), _M_string(0) {}

	/**
	* Construct from an ostream.
	*
	* The delimiter string @a c is written to the stream after every Tp
	* written to the stream. The delimiter is not copied, and thus must
	* not be destroyed while this iterator is in use.
	*
	* @param __s Underlying ostream to write to.
	* @param __c CharT delimiter string to insert.
	*/
	ostream_iterator(ostream_type& __s, const _CharT* __c) _GLIBCXX_NOEXCEPT
	: _M_stream(std::__addressof(__s)), _M_string(__c) { }

	/// Copy constructor.
	ostream_iterator(const ostream_iterator& __obj) _GLIBCXX_NOEXCEPT
	: _M_stream(__obj._M_stream), _M_string(__obj._M_string) { }

	#if __cplusplus >= 201103L
	ostream_iterator& operator=(const ostream_iterator&) = default;
	#endif

	/// Writes @a value to underlying ostream using operator<<. If
	/// constructed with delimiter string, writes delimiter to ostream.
	ostream_iterator&
	operator=(const _Tp& __value)
	{
	__glibcxx_requires_cond(_M_stream != 0,
	_M_message(__gnu_debug::__msg_output_ostream)
	._M_iterator(*this));
	*_M_stream << __value;
	if (_M_string)
	*_M_stream << _M_string;
	return *this;
	}

	_GLIBCXX_NODISCARD
	ostream_iterator&
	operator*() _GLIBCXX_NOEXCEPT
	{ return *this; }

	ostream_iterator&
	operator++() _GLIBCXX_NOEXCEPT
	{ return *this; }

	ostream_iterator&
	operator++(int) _GLIBCXX_NOEXCEPT
	{ return *this; }
	};

	/// @} group iterators

	_GLIBCXX_END_NAMESPACE_VERSION
	} // namespace

	#endif