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The C and C++ Include Header Files
cat -n /usr/include/c++/15/bits/stream_iterator.h
1 // Stream iterators 2 3 // Copyright (C) 2001-2025 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 #ifdef _GLIBCXX_SYSHDR 34 #pragma GCC system_header 35 #endif 36 37 #include <iosfwd> 38 #include <bits/move.h> 39 #include <bits/stl_iterator_base_types.h> 40 #include <debug/debug.h> 41 42 namespace std _GLIBCXX_VISIBILITY(default) 43 { 44 _GLIBCXX_BEGIN_NAMESPACE_VERSION 45 46 /** 47 * @addtogroup iterators 48 * @{ 49 */ 50 51 // Ignore warnings about std::iterator. 52 #pragma GCC diagnostic push 53 #pragma GCC diagnostic ignored "-Wdeprecated-declarations" 54 55 /// Provides input iterator semantics for streams. 56 template<typename _Tp, typename _CharT = char, 57 typename _Traits = char_traits<_CharT>, typename _Dist = ptrdiff_t> 58 class istream_iterator 59 : public iterator<input_iterator_tag, _Tp, _Dist, const _Tp*, const _Tp&> 60 { 61 public: 62 typedef _CharT char_type; 63 typedef _Traits traits_type; 64 typedef basic_istream<_CharT, _Traits> istream_type; 65 66 private: 67 istream_type* _M_stream; 68 _Tp _M_value; 69 // This bool becomes false at end-of-stream. It should be sufficient to 70 // check _M_stream != nullptr instead, but historically we did not set 71 // _M_stream to null when reaching the end, so we need to keep this flag. 72 bool _M_ok; 73 74 public: 75 /// Construct end of input stream iterator. 76 _GLIBCXX_CONSTEXPR istream_iterator() 77 _GLIBCXX_NOEXCEPT_IF(is_nothrow_default_constructible<_Tp>::value) 78 : _M_stream(0), _M_value(), _M_ok(false) {} 79 80 /// Construct start of input stream iterator. 81 istream_iterator(istream_type& __s) 82 : _M_stream(std::__addressof(__s)), _M_ok(true) 83 { _M_read(); } 84 85 _GLIBCXX_CONSTEXPR 86 istream_iterator(const istream_iterator& __obj) 87 _GLIBCXX_NOEXCEPT_IF(is_nothrow_copy_constructible<_Tp>::value) 88 : _M_stream(__obj._M_stream), _M_value(__obj._M_value), 89 _M_ok(__obj._M_ok) 90 { } 91 92 #if __cplusplus > 201703L && __cpp_lib_concepts 93 constexpr 94 istream_iterator(default_sentinel_t) 95 noexcept(is_nothrow_default_constructible_v<_Tp>) 96 : istream_iterator() { } 97 #endif 98 99 #if __cplusplus >= 201103L 100 istream_iterator& operator=(const istream_iterator&) = default; 101 ~istream_iterator() = default; 102 #endif 103 104 _GLIBCXX_NODISCARD 105 const _Tp& 106 operator*() const _GLIBCXX_NOEXCEPT 107 { 108 __glibcxx_requires_cond(_M_ok, 109 _M_message(__gnu_debug::__msg_deref_istream) 110 ._M_iterator(*this)); 111 return _M_value; 112 } 113 114 _GLIBCXX_NODISCARD 115 const _Tp* 116 operator->() const _GLIBCXX_NOEXCEPT 117 { return std::__addressof((operator*())); } 118 119 istream_iterator& 120 operator++() 121 { 122 __glibcxx_requires_cond(_M_ok, 123 _M_message(__gnu_debug::__msg_inc_istream) 124 ._M_iterator(*this)); 125 _M_read(); 126 return *this; 127 } 128 129 istream_iterator 130 operator++(int) 131 { 132 __glibcxx_requires_cond(_M_ok, 133 _M_message(__gnu_debug::__msg_inc_istream) 134 ._M_iterator(*this)); 135 istream_iterator __tmp = *this; 136 _M_read(); 137 return __tmp; 138 } 139 140 private: 141 bool 142 _M_equal(const istream_iterator& __x) const _GLIBCXX_NOEXCEPT 143 { 144 // Ideally this would just return _M_stream == __x._M_stream, 145 // but code compiled with old versions never sets _M_stream to null. 146 return (_M_ok == __x._M_ok) && (!_M_ok || _M_stream == __x._M_stream); 147 } 148 149 void 150 _M_read() 151 { 152 if (_M_stream && !(*_M_stream >> _M_value)) 153 { 154 _M_stream = 0; 155 _M_ok = false; 156 } 157 } 158 159 /// Return true if the iterators refer to the same stream, 160 /// or are both at end-of-stream. 161 _GLIBCXX_NODISCARD 162 friend bool 163 operator==(const istream_iterator& __x, const istream_iterator& __y) 164 _GLIBCXX_NOEXCEPT 165 { return __x._M_equal(__y); } 166 167 #if __cpp_impl_three_way_comparison < 201907L 168 /// Return true if the iterators refer to different streams, 169 /// or if one is at end-of-stream and the other is not. 170 _GLIBCXX_NODISCARD 171 friend bool 172 operator!=(const istream_iterator& __x, const istream_iterator& __y) 173 _GLIBCXX_NOEXCEPT 174 { return !__x._M_equal(__y); } 175 #endif 176 177 #if __cplusplus > 201703L && __cpp_lib_concepts 178 [[nodiscard]] 179 friend bool 180 operator==(const istream_iterator& __i, default_sentinel_t) noexcept 181 { return !__i._M_stream; } 182 #endif 183 }; 184 185 /** 186 * @brief Provides output iterator semantics for streams. 187 * 188 * This class provides an iterator to write to an ostream. The type Tp is 189 * the only type written by this iterator and there must be an 190 * operator<<(Tp) defined. 191 * 192 * @tparam _Tp The type to write to the ostream. 193 * @tparam _CharT The ostream char_type. 194 * @tparam _Traits The ostream char_traits. 195 */ 196 template<typename _Tp, typename _CharT = char, 197 typename _Traits = char_traits<_CharT> > 198 class ostream_iterator 199 : public iterator<output_iterator_tag, void, void, void, void> 200 { 201 public: 202 ///@{ 203 /// Public typedef 204 #if __cplusplus > 201703L 205 using difference_type = ptrdiff_t; 206 #endif 207 typedef _CharT char_type; 208 typedef _Traits traits_type; 209 typedef basic_ostream<_CharT, _Traits> ostream_type; 210 ///@} 211 212 private: 213 ostream_type* _M_stream; 214 const _CharT* _M_string; 215 216 public: 217 /// Construct from an ostream. 218 ostream_iterator(ostream_type& __s) _GLIBCXX_NOEXCEPT 219 : _M_stream(std::__addressof(__s)), _M_string(0) {} 220 221 /** 222 * Construct from an ostream. 223 * 224 * The delimiter string @a c is written to the stream after every Tp 225 * written to the stream. The delimiter is not copied, and thus must 226 * not be destroyed while this iterator is in use. 227 * 228 * @param __s Underlying ostream to write to. 229 * @param __c CharT delimiter string to insert. 230 */ 231 ostream_iterator(ostream_type& __s, const _CharT* __c) _GLIBCXX_NOEXCEPT 232 : _M_stream(std::__addressof(__s)), _M_string(__c) { } 233 234 /// Copy constructor. 235 ostream_iterator(const ostream_iterator& __obj) _GLIBCXX_NOEXCEPT 236 : _M_stream(__obj._M_stream), _M_string(__obj._M_string) { } 237 238 #if __cplusplus >= 201103L 239 ostream_iterator& operator=(const ostream_iterator&) = default; 240 #endif 241 242 /// Writes @a value to underlying ostream using operator<<. If 243 /// constructed with delimiter string, writes delimiter to ostream. 244 ostream_iterator& 245 operator=(const _Tp& __value) 246 { 247 __glibcxx_requires_cond(_M_stream != 0, 248 _M_message(__gnu_debug::__msg_output_ostream) 249 ._M_iterator(*this)); 250 *_M_stream << __value; 251 if (_M_string) 252 *_M_stream << _M_string; 253 return *this; 254 } 255 256 _GLIBCXX_NODISCARD 257 ostream_iterator& 258 operator*() _GLIBCXX_NOEXCEPT 259 { return *this; } 260 261 ostream_iterator& 262 operator++() _GLIBCXX_NOEXCEPT 263 { return *this; } 264 265 ostream_iterator& 266 operator++(int) _GLIBCXX_NOEXCEPT 267 { return *this; } 268 }; 269 #pragma GCC diagnostic pop 270 271 /// @} group iterators 272 273 _GLIBCXX_END_NAMESPACE_VERSION 274 } // namespace 275 276 #endif
