1 // Stream iterators 2 3 // Copyright (C) 2001-2019 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 <debug/debug.h> 36 37 namespace std _GLIBCXX_VISIBILITY(default) 38 { 39 _GLIBCXX_BEGIN_NAMESPACE_VERSION 40 41 /** 42 * @addtogroup iterators 43 * @{ 44 */ 45 46 /// Provides input iterator semantics for streams. 47 template<typename _Tp, typename _CharT = char, 48 typename _Traits = char_traits<_CharT>, typename _Dist = ptrdiff_t> 49 class istream_iterator 50 : public iterator<input_iterator_tag, _Tp, _Dist, const _Tp*, const _Tp&> 51 { 52 public: 53 typedef _CharT char_type; 54 typedef _Traits traits_type; 55 typedef basic_istream<_CharT, _Traits> istream_type; 56 57 private: 58 istream_type* _M_stream; 59 _Tp _M_value; 60 bool _M_ok; 61 62 public: 63 /// Construct end of input stream iterator. 64 _GLIBCXX_CONSTEXPR istream_iterator() 65 : _M_stream(0), _M_value(), _M_ok(false) {} 66 67 /// Construct start of input stream iterator. 68 istream_iterator(istream_type& __s) 69 : _M_stream(std::__addressof(__s)) 70 { _M_read(); } 71 72 istream_iterator(const istream_iterator& __obj) 73 : _M_stream(__obj._M_stream), _M_value(__obj._M_value), 74 _M_ok(__obj._M_ok) 75 { } 76 77 #if __cplusplus >= 201103L 78 istream_iterator& operator=(const istream_iterator&) = default; 79 #endif 80 81 const _Tp& 82 operator*() const 83 { 84 __glibcxx_requires_cond(_M_ok, 85 _M_message(__gnu_debug::__msg_deref_istream) 86 ._M_iterator(*this)); 87 return _M_value; 88 } 89 90 const _Tp* 91 operator->() const { return std::__addressof((operator*())); } 92 93 istream_iterator& 94 operator++() 95 { 96 __glibcxx_requires_cond(_M_ok, 97 _M_message(__gnu_debug::__msg_inc_istream) 98 ._M_iterator(*this)); 99 _M_read(); 100 return *this; 101 } 102 103 istream_iterator 104 operator++(int) 105 { 106 __glibcxx_requires_cond(_M_ok, 107 _M_message(__gnu_debug::__msg_inc_istream) 108 ._M_iterator(*this)); 109 istream_iterator __tmp = *this; 110 _M_read(); 111 return __tmp; 112 } 113 114 bool 115 _M_equal(const istream_iterator& __x) const 116 { return (_M_ok == __x._M_ok) && (!_M_ok || _M_stream == __x._M_stream); } 117 118 private: 119 void 120 _M_read() 121 { 122 _M_ok = (_M_stream && *_M_stream) ? true : false; 123 if (_M_ok) 124 { 125 *_M_stream >> _M_value; 126 _M_ok = *_M_stream ? true : false; 127 } 128 } 129 }; 130 131 /// Return true if x and y are both end or not end, or x and y are the same. 132 template<typename _Tp, typename _CharT, typename _Traits, typename _Dist> 133 inline bool 134 operator==(const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __x, 135 const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __y) 136 { return __x._M_equal(__y); } 137 138 /// Return false if x and y are both end or not end, or x and y are the same. 139 template <class _Tp, class _CharT, class _Traits, class _Dist> 140 inline bool 141 operator!=(const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __x, 142 const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __y) 143 { return !__x._M_equal(__y); } 144 145 /** 146 * @brief Provides output iterator semantics for streams. 147 * 148 * This class provides an iterator to write to an ostream. The type Tp is 149 * the only type written by this iterator and there must be an 150 * operator<<(Tp) defined. 151 * 152 * @tparam _Tp The type to write to the ostream. 153 * @tparam _CharT The ostream char_type. 154 * @tparam _Traits The ostream char_traits. 155 */ 156 template<typename _Tp, typename _CharT = char, 157 typename _Traits = char_traits<_CharT> > 158 class ostream_iterator 159 : public iterator<output_iterator_tag, void, void, void, void> 160 { 161 public: 162 //@{ 163 /// Public typedef 164 typedef _CharT char_type; 165 typedef _Traits traits_type; 166 typedef basic_ostream<_CharT, _Traits> ostream_type; 167 //@} 168 169 private: 170 ostream_type* _M_stream; 171 const _CharT* _M_string; 172 173 public: 174 /// Construct from an ostream. 175 ostream_iterator(ostream_type& __s) 176 : _M_stream(std::__addressof(__s)), _M_string(0) {} 177 178 /** 179 * Construct from an ostream. 180 * 181 * The delimiter string @a c is written to the stream after every Tp 182 * written to the stream. The delimiter is not copied, and thus must 183 * not be destroyed while this iterator is in use. 184 * 185 * @param __s Underlying ostream to write to. 186 * @param __c CharT delimiter string to insert. 187 */ 188 ostream_iterator(ostream_type& __s, const _CharT* __c) 189 : _M_stream(&__s), _M_string(__c) { } 190 191 /// Copy constructor. 192 ostream_iterator(const ostream_iterator& __obj) 193 : _M_stream(__obj._M_stream), _M_string(__obj._M_string) { } 194 195 #if __cplusplus >= 201103L 196 ostream_iterator& operator=(const ostream_iterator&) = default; 197 #endif 198 199 /// Writes @a value to underlying ostream using operator<<. If 200 /// constructed with delimiter string, writes delimiter to ostream. 201 ostream_iterator& 202 operator=(const _Tp& __value) 203 { 204 __glibcxx_requires_cond(_M_stream != 0, 205 _M_message(__gnu_debug::__msg_output_ostream) 206 ._M_iterator(*this)); 207 *_M_stream << __value; 208 if (_M_string) *_M_stream << _M_string; 209 return *this; 210 } 211 212 ostream_iterator& 213 operator*() 214 { return *this; } 215 216 ostream_iterator& 217 operator++() 218 { return *this; } 219 220 ostream_iterator& 221 operator++(int) 222 { return *this; } 223 }; 224 225 // @} group iterators 226 227 _GLIBCXX_END_NAMESPACE_VERSION 228 } // namespace 229 230 #endif 231