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The C and C++ Include Header Files
/usr/include/c++/13/bits/stream_iterator.h
$ cat -n /usr/include/c++/13/bits/stream_iterator.h 1 // Stream iterators 2 3 // Copyright (C) 2001-2023 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 bits/stream_iterator.h 26 * This is an internal header file, included by other library headers. 27 * Do not attempt to use it directly. @headername{iterator} 28 */ 29 30 #ifndef _STREAM_ITERATOR_H 31 #define _STREAM_ITERATOR_H 1 32 33 #pragma GCC system_header 34 35 #include <iosfwd> 36 #include <bits/move.h> 37 #include <bits/stl_iterator_base_types.h> 38 #include <debug/debug.h> 39 40 namespace std _GLIBCXX_VISIBILITY(default) 41 { 42 _GLIBCXX_BEGIN_NAMESPACE_VERSION 43 44 /** 45 * @addtogroup iterators 46 * @{ 47 */ 48 49 // Ignore warnings about std::iterator. 50 #pragma GCC diagnostic push 51 #pragma GCC diagnostic ignored "-Wdeprecated-declarations" 52 53 /// Provides input iterator semantics for streams. 54 template<typename _Tp, typename _CharT = char, 55 typename _Traits = char_traits<_CharT>, typename _Dist = ptrdiff_t> 56 class istream_iterator 57 : public iterator<input_iterator_tag, _Tp, _Dist, const _Tp*, const _Tp&> 58 { 59 public: 60 typedef _CharT char_type; 61 typedef _Traits traits_type; 62 typedef basic_istream<_CharT, _Traits> istream_type; 63 64 private: 65 istream_type* _M_stream; 66 _Tp _M_value; 67 // This bool becomes false at end-of-stream. It should be sufficient to 68 // check _M_stream != nullptr instead, but historically we did not set 69 // _M_stream to null when reaching the end, so we need to keep this flag. 70 bool _M_ok; 71 72 public: 73 /// Construct end of input stream iterator. 74 _GLIBCXX_CONSTEXPR istream_iterator() 75 _GLIBCXX_NOEXCEPT_IF(is_nothrow_default_constructible<_Tp>::value) 76 : _M_stream(0), _M_value(), _M_ok(false) {} 77 78 /// Construct start of input stream iterator. 79 istream_iterator(istream_type& __s) 80 : _M_stream(std::__addressof(__s)), _M_ok(true) 81 { _M_read(); } 82 83 _GLIBCXX_CONSTEXPR 84 istream_iterator(const istream_iterator& __obj) 85 _GLIBCXX_NOEXCEPT_IF(is_nothrow_copy_constructible<_Tp>::value) 86 : _M_stream(__obj._M_stream), _M_value(__obj._M_value), 87 _M_ok(__obj._M_ok) 88 { } 89 90 #if __cplusplus > 201703L && __cpp_lib_concepts 91 constexpr 92 istream_iterator(default_sentinel_t) 93 noexcept(is_nothrow_default_constructible_v<_Tp>) 94 : istream_iterator() { } 95 #endif 96 97 #if __cplusplus >= 201103L 98 istream_iterator& operator=(const istream_iterator&) = default; 99 ~istream_iterator() = default; 100 #endif 101 102 _GLIBCXX_NODISCARD 103 const _Tp& 104 operator*() const _GLIBCXX_NOEXCEPT 105 { 106 __glibcxx_requires_cond(_M_ok, 107 _M_message(__gnu_debug::__msg_deref_istream) 108 ._M_iterator(*this)); 109 return _M_value; 110 } 111 112 _GLIBCXX_NODISCARD 113 const _Tp* 114 operator->() const _GLIBCXX_NOEXCEPT 115 { return std::__addressof((operator*())); } 116 117 istream_iterator& 118 operator++() 119 { 120 __glibcxx_requires_cond(_M_ok, 121 _M_message(__gnu_debug::__msg_inc_istream) 122 ._M_iterator(*this)); 123 _M_read(); 124 return *this; 125 } 126 127 istream_iterator 128 operator++(int) 129 { 130 __glibcxx_requires_cond(_M_ok, 131 _M_message(__gnu_debug::__msg_inc_istream) 132 ._M_iterator(*this)); 133 istream_iterator __tmp = *this; 134 _M_read(); 135 return __tmp; 136 } 137 138 private: 139 bool 140 _M_equal(const istream_iterator& __x) const _GLIBCXX_NOEXCEPT 141 { 142 // Ideally this would just return _M_stream == __x._M_stream, 143 // but code compiled with old versions never sets _M_stream to null. 144 return (_M_ok == __x._M_ok) && (!_M_ok || _M_stream == __x._M_stream); 145 } 146 147 void 148 _M_read() 149 { 150 if (_M_stream && !(*_M_stream >> _M_value)) 151 { 152 _M_stream = 0; 153 _M_ok = false; 154 } 155 } 156 157 /// Return true if the iterators refer to the same stream, 158 /// or are both at end-of-stream. 159 _GLIBCXX_NODISCARD 160 friend bool 161 operator==(const istream_iterator& __x, const istream_iterator& __y) 162 _GLIBCXX_NOEXCEPT 163 { return __x._M_equal(__y); } 164 165 #if __cpp_impl_three_way_comparison < 201907L 166 /// Return true if the iterators refer to different streams, 167 /// or if one is at end-of-stream and the other is not. 168 _GLIBCXX_NODISCARD 169 friend bool 170 operator!=(const istream_iterator& __x, const istream_iterator& __y) 171 _GLIBCXX_NOEXCEPT 172 { return !__x._M_equal(__y); } 173 #endif 174 175 #if __cplusplus > 201703L && __cpp_lib_concepts 176 [[nodiscard]] 177 friend bool 178 operator==(const istream_iterator& __i, default_sentinel_t) noexcept 179 { return !__i._M_stream; } 180 #endif 181 }; 182 183 /** 184 * @brief Provides output iterator semantics for streams. 185 * 186 * This class provides an iterator to write to an ostream. The type Tp is 187 * the only type written by this iterator and there must be an 188 * operator<<(Tp) defined. 189 * 190 * @tparam _Tp The type to write to the ostream. 191 * @tparam _CharT The ostream char_type. 192 * @tparam _Traits The ostream char_traits. 193 */ 194 template<typename _Tp, typename _CharT = char, 195 typename _Traits = char_traits<_CharT> > 196 class ostream_iterator 197 : public iterator<output_iterator_tag, void, void, void, void> 198 { 199 public: 200 ///@{ 201 /// Public typedef 202 #if __cplusplus > 201703L 203 using difference_type = ptrdiff_t; 204 #endif 205 typedef _CharT char_type; 206 typedef _Traits traits_type; 207 typedef basic_ostream<_CharT, _Traits> ostream_type; 208 ///@} 209 210 private: 211 ostream_type* _M_stream; 212 const _CharT* _M_string; 213 214 public: 215 /// Construct from an ostream. 216 ostream_iterator(ostream_type& __s) _GLIBCXX_NOEXCEPT 217 : _M_stream(std::__addressof(__s)), _M_string(0) {} 218 219 /** 220 * Construct from an ostream. 221 * 222 * The delimiter string @a c is written to the stream after every Tp 223 * written to the stream. The delimiter is not copied, and thus must 224 * not be destroyed while this iterator is in use. 225 * 226 * @param __s Underlying ostream to write to. 227 * @param __c CharT delimiter string to insert. 228 */ 229 ostream_iterator(ostream_type& __s, const _CharT* __c) _GLIBCXX_NOEXCEPT 230 : _M_stream(std::__addressof(__s)), _M_string(__c) { } 231 232 /// Copy constructor. 233 ostream_iterator(const ostream_iterator& __obj) _GLIBCXX_NOEXCEPT 234 : _M_stream(__obj._M_stream), _M_string(__obj._M_string) { } 235 236 #if __cplusplus >= 201103L 237 ostream_iterator& operator=(const ostream_iterator&) = default; 238 #endif 239 240 /// Writes @a value to underlying ostream using operator<<. If 241 /// constructed with delimiter string, writes delimiter to ostream. 242 ostream_iterator& 243 operator=(const _Tp& __value) 244 { 245 __glibcxx_requires_cond(_M_stream != 0, 246 _M_message(__gnu_debug::__msg_output_ostream) 247 ._M_iterator(*this)); 248 *_M_stream << __value; 249 if (_M_string) 250 *_M_stream << _M_string; 251 return *this; 252 } 253 254 _GLIBCXX_NODISCARD 255 ostream_iterator& 256 operator*() _GLIBCXX_NOEXCEPT 257 { return *this; } 258 259 ostream_iterator& 260 operator++() _GLIBCXX_NOEXCEPT 261 { return *this; } 262 263 ostream_iterator& 264 operator++(int) _GLIBCXX_NOEXCEPT 265 { return *this; } 266 }; 267 #pragma GCC diagnostic pop 268 269 /// @} group iterators 270 271 _GLIBCXX_END_NAMESPACE_VERSION 272 } // namespace 273 274 #endif
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