// Stream iterators // Copyright (C) 2001-2020 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