stream_iterator.h
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// 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()
: _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)
: _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
const _Tp&
operator*() const
{
__glibcxx_requires_cond(_M_ok,
_M_message(__gnu_debug::__msg_deref_istream)
._M_iterator(*this));
return _M_value;
}
const _Tp*
operator->() const { 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
{
// 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.
friend bool
operator==(const istream_iterator& __x, const istream_iterator& __y)
{ return __x._M_equal(__y); }
/// Return true if the iterators refer to different streams,
/// or if one is at end-of-stream and the other is not.
friend bool
operator!=(const istream_iterator& __x, const istream_iterator& __y)
{ return !__x._M_equal(__y); }
#if __cplusplus > 201703L && __cpp_lib_concepts
friend bool
operator==(const istream_iterator& __i, default_sentinel_t)
{ 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:
#if __cplusplus > 201703L
constexpr ostream_iterator() noexcept
: _M_stream(nullptr), _M_string(nullptr) { }
#endif
/// Construct from an ostream.
ostream_iterator(ostream_type& __s)
: _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)
: _M_stream(std::__addressof(__s)), _M_string(__c) { }
/// Copy constructor.
ostream_iterator(const ostream_iterator& __obj)
: _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;
}
ostream_iterator&
operator*()
{ return *this; }
ostream_iterator&
operator++()
{ return *this; }
ostream_iterator&
operator++(int)
{ return *this; }
};
/// @} group iterators
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
#endif
debug.h
std::__addressof
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
Definition: move.h:49
std
ISO C++ entities toplevel namespace is std.
std::basic_istream
Template class basic_istream.
Definition: istream:59
std::basic_ostream
Template class basic_ostream.
Definition: ostream:59
std::iterator
Common iterator class.
Definition: stl_iterator_base_types.h:128
std::iterator< output_iterator_tag, void, void, void, void >::difference_type
void difference_type
Distance between iterators is represented as this type.
Definition: stl_iterator_base_types.h:134
std::istream_iterator
Provides input iterator semantics for streams.
Definition: stream_iterator.h:51
std::istream_iterator::operator!=
friend bool operator!=(const istream_iterator &__x, const istream_iterator &__y)
Return true if the iterators refer to different streams, or if one is at end-of-stream and the other ...
Definition: stream_iterator.h:153
std::istream_iterator::istream_iterator
istream_iterator(istream_type &__s)
Construct start of input stream iterator.
Definition: stream_iterator.h:71
std::istream_iterator::istream_iterator
constexpr istream_iterator()
Construct end of input stream iterator.
Definition: stream_iterator.h:67
std::istream_iterator::operator==
friend bool operator==(const istream_iterator &__x, const istream_iterator &__y)
Return true if the iterators refer to the same stream, or are both at end-of-stream.
Definition: stream_iterator.h:147
std::ostream_iterator
Provides output iterator semantics for streams.
Definition: stream_iterator.h:178
std::ostream_iterator::char_type
_CharT char_type
Public typedef.
Definition: stream_iterator.h:185
std::ostream_iterator::operator=
ostream_iterator & operator=(const _Tp &__value)
Writes value to underlying ostream using operator<<. If constructed with delimiter string,...
Definition: stream_iterator.h:228
std::ostream_iterator::ostream_iterator
ostream_iterator(ostream_type &__s)
Construct from an ostream.
Definition: stream_iterator.h:201
std::ostream_iterator::traits_type
_Traits traits_type
Public typedef.
Definition: stream_iterator.h:186
std::ostream_iterator::ostream_iterator
ostream_iterator(const ostream_iterator &__obj)
Copy constructor.
Definition: stream_iterator.h:218
std::ostream_iterator::ostream_type
basic_ostream< _CharT, _Traits > ostream_type
Public typedef.
Definition: stream_iterator.h:187
std::ostream_iterator::ostream_iterator
ostream_iterator(ostream_type &__s, const _CharT *__c)
Definition: stream_iterator.h:214